Medical treatment system using a plurality of fluid lines

Abstract

To enhance patient comfort and ease of use.SOLUTION: A peritoneal dialysis system may include a control system that can adjust the volume of fluid infused into the peritoneal cavity to prevent the intraperitoneal fluid volume from exceeding a predetermined amount. The control system can adjust, by adding one or more therapy cycles, allowing for filling volumes during each cycle to be reduced. The control system may continue to allow the fluid to drain from the peritoneal cavity as completely as possible before starting the next therapy cycle. The control system may also adjust a dwelling time of fluid within the peritoneal cavity during therapy cycles to complete a therapy within a scheduled time period.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to medical systems and methods that use multiple fluid lines. [Background technology]

[0002] Peritoneal dialysis (PD) involves the periodic infusion of sterile water dialysate (called peritoneal dialysate or dialysate) into a patient's peritoneal cavity. Diffusion and osmosis exchanges occur between the dialysate and the bloodstream across natural body membranes. These exchanges transfer waste products into the dialysate, which the kidneys normally excrete. The waste products typically consist of solutes, such as sodium and chloride ions, and other compounds normally excreted through the kidneys, such as urea, creatinine, and water. The diffusion of water across the peritoneal membrane during dialysis is called ultrafiltration.

[0003] Conventional peritoneal dialysis fluid contains glucose in a concentration sufficient to generate the osmotic pressure necessary to remove water from the patient through ultrafiltration. Continuous ambulatory peritoneal dialysis (CAPD) is a common form of PD. Patients perform CAPD manually approximately four times per day. During the drainage / induction procedure for CAPD, the patient first drains used peritoneal dialysis fluid from their peritoneal cavity and then injects fresh peritoneal dialysis fluid into their peritoneal cavity. This drainage and induction procedure typically takes about an hour.

[0004] Automated peritoneal dialysis (APD) is another common form of PD. APD uses a dialysis machine called a cycler to automatically introduce, dwell, and withdraw peritoneal dialysate to and from the patient's peritoneal cavity. APD is particularly attractive to PD patients because it can be performed overnight while the patient sleeps. This relieves the patient from the daily demands of CAPD during their waking and working hours.

[0005] An APD sequence typically lasts several hours. It often begins with an initial drain phase, which emptys spent dialysate from the peritoneal cavity. The APD sequence then progresses through a series of induction, dwell, and drain phases, which are repeated repeatedly. Each induction / dwell / drain sequence is referred to as a cycle.

[0006] During the inlet phase, the cycler transfers a predetermined volume of warmed, fresh dialysate to the patient's peritoneal cavity. The dialysate remains (or "dwells") in the cavity for a period of time, referred to as the dwell phase. During the outlet phase, the cycler removes used dialysate from the peritoneal cavity.

[0007] The number of fill / dwell / drain cycles required during a given APD session depends on the total volume of dialysate prescribed for the patient's APD therapy and is either entered as part of the treatment prescription or calculated by the cycler.

[0008] APD can be and is implemented in a variety of ways. Continuous cyclic peritoneal dialysis (CCPD) is one commonly used method of APD. During each induction / dwell / drain phase of CCPD, a cycler introduces a defined volume of dialysate. After a defined dwell period, the cycler completely withdraws this fluid volume from the patient, emptying or "drying" the peritoneal cavity. Typically, CCPD employs four to eight induction / dwell / drain cycles to achieve the defined treatment volume.

[0009] After the last prescribed induction / dwell / delivery cycle during CCPD, the cycler delivers a final induction volume. The final induction volume remains in the patient for an extended period of time. It is delivered at the beginning of the next CCPD session overnight or during a midday exchange. The final induction volume can contain a different glucose concentration than the induction volumes of successive CCPD induction / dwell / delivery induction cycles delivered by the cycler.

[0010] Intermittent peritoneal dialysis (IPD) is another APD procedure. IPD is typically used in emergencies when a patient suddenly enters dialysis treatment. IPD cannot replace CAPD or be performed at home, but can also be used when a patient requires PD.

[0011] Like CCPD, IPD involves a series of fill / dwell / drain cycles. Unlike CCPD, IPD does not have a final fill stage. In IPD, the patient's peritoneal cavity is left empty of dialysate (or "dry") between APD treatment sessions.

[0012] Tidal peritoneal dialysis (TPD) is another APD procedure. Like CCPD, TPD involves a series of infusion / dwell / drain cycles. Unlike CCPD, TPD does not completely drain dialysate from the peritoneal cavity during each drain phase. Instead, TPD establishes a base volume during the first infusion phase and drains only a portion of this volume during the first drain phase. Subsequent infusion / dwell / drain cycles introduce and then drain an exchange volume above the base volume. The final drain phase removes all dialysate from the peritoneal cavity.

[0013] There is a variation in TPD with cycles being completely withdrawn from the patient and a new complete base volume of dialysis being introduced. A TPD can have a final induction cycle, like a CCPD, or alternatively, a TPD can avoid a final induction cycle, like an IPD. Summary of the Invention [Problem to be solved by the invention]

[0014] APD offers flexibility and improved quality of life to those who require dialysis. APD can relieve patients from the fatigue and inconvenience that the daily practice of CAPD presents to some individuals. APD can give patients back work hours that do not require dialysis exchanges.

[0015] However, the complexity and size of past dialysis machines and associated consumables for various APD procedures has hindered widespread patient acceptance of APD as an alternative to manual peritoneal dialysis methods. [Means for solving the problem]

[0016] Aspects of the invention relate to various components, systems, and methods used in medical applications, including medical infusion procedures such as peritoneal dialysis. In some cases, aspects of the invention are limited to peritoneal dialysis applications, while other aspects are limited to more general dialysis applications (e.g., hemodialysis) or infusion applications, and other aspects are limited to more general methods or processes. Thus, while many of the exemplary embodiments described relate to APD, aspects of the invention are not necessarily limited to APD systems and methods.

[0017] In one aspect of the present invention, a dialysis system can include a tube condition detector that detects the presence or absence of a tubing segment, such as a portion of a patient line connected to a patient access portion to supply dialysate to a peritoneal cavity. The tube condition detector can include a first light emitter having a first optical axis directed toward a space in which the tubing segment is located, and a second light emitter adjacent to the first light emitter and having a second optical axis directed toward the space. An optical sensor is positioned on a side of the space opposite the first and second light emitters and is positioned to receive light emitted by the first and second light emitters to determine the presence or absence of the tubing segment in the space.

[0018] In one embodiment, the first optical axis may be substantially collinear with the sensor optical axis of the optical sensor and pass through an approximate center of the tube segment when the tube segment is disposed in space. In contrast, the second optical axis may be substantially parallel to the first optical axis, and thus the second optical axis may be offset from the center of the tube segment and the sensor optical axis.

[0019] The optical sensor can be positioned to detect a range of light levels when the tube segment is present in the space (e.g., higher and / or lower light levels than the light levels detected when the tube segment is not present in the space). However, the optical sensor can detect a lower light level from the second light emitter when the tube segment is present in the space than the light level detected when the tube segment is not present in the space. For example, when the tube segment is present in the space, the light levels detected for both the first and second light emitters can be within about 15-20% of the calibrated light level for the first and second light emitters, the calibrated light level being the level detected when the tube segment is known not to be present in the space. However, when the tube segment is not present in the space, the light level detected for the second light emitter can be about 15-20% or less of the calibrated light level for the second light emitter. This low light level detection can be used to determine the presence of a tube segment in the space.

[0020] In another embodiment, the tube condition detector can be positioned to detect whether there is liquid in the tube segment, e.g., whether the patient line is properly prepared for use. For example, the detector can include a third light emitter having a third optical axis positioned at an oblique angle relative to the sensor optical axis. The oblique angle can be between 90 and 180 degrees (e.g., approximately 110 and 120 degrees). The optical sensor and third light emitter can be positioned such that when the tube segment is present in the space and does not contain liquid, the light level detected by the optical sensor is greater than or equal to approximately 150% of the calibrated light level detected when the tube segment is not present in the space. Additionally, when the tube segment is present in the space and contains liquid, the optical sensor can detect a light level from the third light emitter that is less than or equal to approximately 125% of the calibrated light level. In this manner, the optical sensor and third light emitter can be positioned such that when the tube segment is present in the space and does not contain liquid, the light level detected by the optical sensor is greater than or equal to a threshold value, and when the tube segment is present in the space and contains liquid, the light level detected by the optical sensor is less than or equal to the threshold value. This configuration may allow the detector to determine whether liquid is contained in the patient line, for example, whether the patient line is properly primed. In one embodiment, the third light emitter and optical sensor can be positioned such that the optical sensor receives light from the third light emitter both when the tube compartment in the space is filled with liquid and when the tube compartment in the space is empty of liquid. In this way, the presence or absence of liquid in the tube compartment can be determined based on the detected light intensity rather than the presence or absence of light. This can help the system avoid false state detections that may occur if the detector uses the absence of detected light to indicate a condition such as the presence of liquid in the tube compartment. That is, because the optical sensor detects light from the third light emitter regardless of the presence of liquid, the optical sensor can determine whether the third light emitter is operating properly (or not operating at all).The space in which the tube segment is held can be arranged to receive and hold the tube segment, which may have a cylindrical outer surface, without substantially deforming the tube segment. In this way, the detector can operate without deforming the tube segment, thereby avoiding potential problems such as pinching, reduced flow, etc. in the tube segment.

[0021] In another aspect of the present invention, a tube condition detector for detecting whether a tube segment contains liquid can include a fill state light emitter having an optical axis positioned to pass through a space in which the tube segment is disposed. The space can be configured to receive a tube segment having a cylindrical outer surface and retain the tube segment without substantially deforming the tube segment. In this manner, the detector may be usable with common tubing frequently used in dialysis systems without requiring special-purpose connectors or other components. An optical sensor can be positioned on the side of the space opposite the fill state light emitter and configured to receive light emitted by the fill state light emitter to determine the presence or absence of liquid in the tube segment. In one embodiment, the optical sensor can have a sensor optical axis positioned at an oblique angle to the optical axis of the fill state light emitter and configured to detect whether liquid is present in the tube segment. The oblique angle can be between 90 and 180 degrees (e.g., approximately 110 and 120 degrees), and the optical sensor can be configured to receive light from the fill state light emitter whether or not liquid is present in the tube segment.

[0022] The optical sensor and fill-state light emitter can be positioned such that when the tube segment is present in the space and does not contain liquid, the light level detected by the optical sensor is above a threshold level, and when the tube segment is present in the space and contains liquid, the light level detected by the optical sensor is below the threshold level. In this manner, if the optical sensor detects a light level below the threshold (e.g., below about 125-150% of the light level detected when no tube segment is present in the space), a determination can be made that the tube segment is filled with liquid. The fill-state light emitter (e.g., with other light emitters) can be light-emitting diodes or other electromagnetic-emitting components, such as devices that emit infrared, ultraviolet, visible, or other light in the visible and / or invisible spectrum.

[0023] In one embodiment, the tube status detector can include a first light emitter having a first optical axis directed toward the space and a second light emitter having a second optical axis directed toward the space. The second light emitter can be adjacent to the first light emitter, and the second optical axis can be parallel to the first optical axis. An optical sensor can be positioned on a side of the space opposite the first and second light emitters and can be positioned to receive light emitted by the first and second light emitters to determine the presence or absence of a tube segment within the space. For example, the first and second light emitters can be positioned relative to each other and the optical sensor as described above (e.g., the first optical axis can pass through the center of the tube segment within the space, the second optical axis can be offset from the center of the tube segment, etc.).

[0024] In another aspect of the invention, a peritoneal dialysis system can include at least one pump configured to pump dialysate for delivery to a patient's peritoneal cavity and a patient line fluidly coupled to the at least one pump so that the dialysate delivered from the pump is directed to the patient line. The patient line can have a tip configured for connection to a patient (e.g., for connection to a patient access port that delivers dialysate to the patient's peritoneal cavity). A patient line status detector can be associated with the patient line and configured to detect both the presence of the patient line and its primed state. For example, the patient line status detector can be configured to receive the tip of the patient line and detect the presence of the tip and whether the tip is filled with fluid. This configuration can be useful to allow the system and the patient to verify that the patient line is sufficiently filled with dialysate before connecting the patient line to the patient access port.

[0025] The patient line condition detector can include a cavity that receives the tip of the patient line, one or more light emitters associated with the cavity and positioned to direct light into the cavity, and one or more photodetectors positioned to detect the light emitted by the one or more light emitters. In one embodiment, a single photodetector can be used to determine both whether liquid is in the patient line and the presence or absence of a patient line. The patient line condition detector can be arranged in any manner in which the tube condition detector described above can be arranged. For example, the first and second light emitters can be positioned adjacent to each other and on sides of the cavity that receive the patient line opposite the optical sensor. The third light emitter can be positioned with its optical axis positioned at an oblique angle relative to the sensor axis of the optical sensor, thereby enabling detection of liquid in the patient line. Other features of the tube condition detector described above can be incorporated into the patient line condition detector, including detection and use of relative light source levels to indicate the presence of a patient line and / or the presence of liquid in the patient line.

[0026] In another aspect of the invention, a method for detecting the presence of a tube segment includes emitting a first light along a first optical axis toward a space in which the tube segment is optionally disposed and emitting a second light along a second optical axis toward the space, the first and second lights being emitted from a first side of the space. At least portions of the first and second lights can be detected on a second side of the space opposite the first side, and the presence or absence of the tube segment in the space can be determined based on the detected portions of the first and second lights. The second optical axis can be substantially parallel to the first optical axis, and the first optical axis can pass through the center of the tube segment. In one embodiment, a first calibrated level of the first light can be detected when no tube segment is present in the space, and a first light source level can be detected for the first light when the tube segment is present in the space. The first light source level can be higher or lower than the first calibrated level. However, a second calibrated level of the second light may be detected when no tube segments are present in the space, and a second light source level may be detected for the second light when tube segments are present in the space, the second light source level being lower than the second calibrated level. Thus, detection of a second light source level lower than the second calibrated level may indicate the presence of tube segments in the space. In one embodiment, the second light source level detected for the second light may be about 15-20% or less of the second calibrated level when tube segments are present in the space.

[0027] In another aspect of the invention, a method for detecting the presence of liquid in a tube segment can include emitting light along an optical axis toward a space in which the tube segment is disposed, the tube segment having a cylindrical outer surface, and detecting the light along a sensor optical axis extending into the space, the sensor optical axis being disposed at an oblique angle (e.g., approximately 110-120°) relative to the optical axis. The presence or absence of liquid in the tube segment within the space can be determined based on a detected light source level detected along the sensor optical axis. For example, if the light source level detected along the sensor optical axis is equal to or greater than a threshold level, a determination can be made that fluid is not in the tube segment, and if the light source level detected along the sensor optical axis is equal to or less than the threshold level, a determination can be made that fluid is in the tube segment. The threshold level can be approximately equal to approximately 125-150% of the light source level detected along the sensor optical axis when no tube segment is present within the space.

[0028] In one aspect of the present invention, a disposable fluid-carrying cassette usable with an APD cycler or other infusion device includes a generally planar body having at least one pump chamber recessed in a first side thereof and a plurality of fluid flow paths with channels. A patient line port is positioned for connection to a patient line and can be in fluid communication with at least one pump chamber via at least one fluid path, and a membrane can be attached to the first side of the body across the at least one pump chamber. In one embodiment, the membrane can have a pump chamber portion with an unloaded shape that generally conforms to the pump chamber recess in the body and is operatively positioned for fluid movement within the available space of the pump chamber. If the cassette body includes two or more pump chamber recesses, the membrane can similarly include two or more preformed pump portions. In other embodiments, the membrane need not be included with the cassette; for example, a cycler control surface interacts with the cassette to control pumping and / or valving.

[0029] In another embodiment, the pumping chamber can include one or more spacer elements extending from the inner wall of the recess to, for example, help prevent the membrane from contacting the inner wall, thereby preventing blocking of the inlet / outlet of the pumping chamber, help remove or trap air within the pumping chamber, and / or prevent adhesion of the membrane to the inner wall. The spacer elements can be positioned to minimize deformation of the membrane at the edges of the spacer elements when the membrane is pressed against the spacer elements.

[0030] In another embodiment, the patient line port and the drain line port are disposed at a first end of the body and are fluidly connected to at least one pump chamber via at least one fluid pathway. Meanwhile, multiple dialysate line spikes are disposed at a second end of the body opposite the first end, each of the dialysate line spikes being fluidly connected to at least one pump chamber via at least one fluid pathway. This configuration may enable automatic connection of the dialysate line to the cassette and / or individual occlusion of the patient line and / or drain line relative to the dialysate line. In one embodiment, a heater bag line port is also disposed at the first end of the body and is fluidly connected to at least one pump chamber via at least one fluid pathway. Flexible patient, drain, and heater bag lines can be connected to the patient line port, the drain line port, and the heater bag line port, respectively.

[0031] In another embodiment, the body can include a vacuum vent gap recess formed adjacent to at least one pump chamber. This recess can assist in the removal of fluid (gas and / or liquid) between the membrane and a corresponding control surface of the cycler, for example, by a vacuum port in the control surface. That is, the recess can help ensure that the membrane is not pressed against the vacuum port, leaving the port open to draw fluid into the collection chamber when needed.

[0032] In one embodiment, one or more ports, such as an outlet line port and a heater bag line port, and / or one or more dialysate line spikes, can communicate with a common fluid pathway channel of the cassette base. Optionally, multiple valves can be positioned to control flow in each fluid pathway between at least one pump chamber, a patient line port, an outlet line port, and multiple dialysate line spikes. In one embodiment, a membrane segment can be positioned across each valve and operable to open and close each valve. Similarly, flow through an opening to a pump chamber can be controlled by a corresponding valve that is opened or closed by operation of one or more membrane segments.

[0033] In some embodiments, the membrane can close at least some of the fluid paths in the body, i.e., the body can have open flow channels formed therein that are closed on at least one side by the membrane. In one embodiment, the body can have fluid paths formed on an opposing planar side, and at least some of the fluid paths on the first side can communicate with the fluid paths on the second side.

[0034] In one embodiment, one or more spikes on the cassette (eg, that receives the dialysate) can be covered by a removable spike cap that seals the spike.

[0035] In another aspect of the present invention, a disposable fluid transfer cassette for use with a reusable automated peritoneal dialysis cycler device includes a generally planar body having at least one pump chamber formed as a recess in a first side of the body, a plurality of fluid flow paths including channels, a patient line port positioned for connection to a patient line, the patient line port in fluid communication with the at least one pump chamber via at least one fluid pathway, and a flexible membrane attached to the first side of the body across the at least one pump chamber. A pump chamber portion of the membrane across the at least one pump chamber can have an unloaded shape that generally conforms to a usable area of ​​the pump chamber recess in the body and can be operably positioned for movement of fluid within the pump chamber. In one embodiment, the cassette is configured for operably engaging with a reusable automated peritoneal dialysis cycler device.

[0036] The cassette may include an outlet line port in fluid communication with at least one pump chamber via at least one fluid path and / or a plurality of dialysate line spikes in fluid communication with at least one pump chamber via at least one fluid path, arranged for connection to an outlet line. The pump chamber portion of the membrane may be generally dome-shaped and may include two pump chamber portions having shapes that generally conform to the usable area of ​​the corresponding pump chamber recess. In one embodiment, the volume of the pump chamber portion may be in the range of 85-110% of the usable volume of the pump chamber recess. In another embodiment, the pump chamber portion may be arranged to be 85-110% of the depth of the usable area of ​​the pump chamber recess. In another embodiment, the pump chamber portion may be arranged to have a size in the range of 85-100% of the perimeter of the usable area of ​​the pump chamber recess. The usable area of ​​the pump chamber may be at least partially defined by one or more spacer elements extending from the inner wall of the recess. In one embodiment, the plurality of spacer elements may have progressive lengths or varying heights that define a generally dome-shaped area or other shape. The spacer elements can be arranged in a concentric elliptical pattern or other shape when viewed in a plan view. One or more breaks in the pattern can be provided, for example, to allow for void communication. In one embodiment, the spacer elements can be arranged to minimize deformation of the membrane at the edges of the spacer elements when the membrane is pressed against the spacer elements. In another embodiment, one or more spacers can be configured to prohibit the membrane from covering the fluid inlet and / or outlet in the pump chamber.

[0037] In another aspect of the present invention, a fluid delivery cassette for use with a fluid delivery system of a medical infusion device comprises a generally planar body having at least one pump chamber formed as a recess in a first side of the body and a plurality of flow paths for fluid with channels, the at least one pump chamber having one or more spacer elements extending from an inner wall of the recess; a patient line port arranged for connection to a patient line, the patient line port being in fluid communication with the at least one pump chamber via at least one fluid pathway; a drain line port arranged for connection to a drain line, the drain line port being in fluid communication with the at least one pump chamber via at least one fluid pathway; and a plurality of dialysate line spikes in fluid communication with the at least one pump chamber via at least one fluid pathway.

[0038] In one aspect of the present invention, a disposable component system for use with a fluid line connection system of a peritoneal dialysis system includes a fluid carrying cassette having a generally planar body with at least one pump chamber formed as a recess in a first side of the body and a plurality of fluid flow paths, a dialysate line spike disposed at a first end of the body and in fluid communication with the at least one pump chamber via at least one fluid path, and a spike cap configured to removably cover the dialysate line spike, the cap including at least one raised feature (e.g., an asymmetric or symmetric flange) to assist in removal of the cap for connection to a dialysate line prior to initiation of peritoneal dialysis treatment.

[0039] In one embodiment, the cassette includes a skirt disposed around the spike to receive the end of the spike cap, and there may be a recess between the skirt and the spike positioned to assist in forming a seal between the spike cap and the skirt.

[0040] In another embodiment, a dialysate line cap can be removably connected to the dialysate line, and the dialysate line cap can include a recessed feature (e.g., a symmetrical or asymmetrical groove). At least a portion of the dialysate line cap can comprise a flexible material, such as silicone rubber. The recessed feature can aid in removal of the spike cap from the cassette.

[0041] In another embodiment, the spike cap includes a second raised feature that may act as a stopper for the dialysate line cap. In another embodiment, the major axis of the one or more spikes is substantially in the same plane as the generally planar body of the fluid carrying cassette.

[0042] In another aspect of the invention, a fluid carrying cassette for use with a peritoneal dialysis system includes a generally planar body having at least one pumping chamber formed as a recess in a first side of the body and a plurality of fluid flow paths, and a spike disposed at a first end of the body for engagement with a dialysate line. The spike is in fluid communication with the at least one pumping chamber via the at least one fluid path and can include a distal tip and a lumen disposed such that the distal tip of the spike is disposed substantially near a longitudinal axis of the spike. In one embodiment, the lumen can be disposed substantially offset from the longitudinal axis.

[0043] In another aspect of the present invention, a disposable component system for use with a fluid line connection system of a peritoneal dialysis system includes a spike cap configured to removably cover a spike of a fluid carrying cassette. The cap can include at least one feature that assists in removal of the cap for connection to a dialysate line prior to initiation of peritoneal dialysis treatment. The feature can be a raised feature or a recessed feature and can be configured for engagement with the dialysate line cap.

[0044] In another aspect of the present invention, a disposable component system for use with a fluid line connection system of a peritoneal dialysis system includes a dialysate line cap for removably attaching to a dialysate line, the dialysate line cap including at least one feature that assists in removal of a spike cap to enable connection between the dialysate line and a spike prior to initiation of peritoneal dialysis therapy. The feature can be a raised or recessed feature and can be configured for engagement with the spike cap. Indicia can be associated with the dialysate line such that, for example, a dialysate associated with the line is identified and can affect at least one function of the peritoneal dialysis system.

[0045] In another aspect of the present invention, a medical infusion fluid delivery system, such as an APD system, can be configured to remove caps from one or more lines (e.g., dialysate lines) with one or more spikes or other connection ports on a fluid delivery cassette and connect these lines. This feature can provide advantages, such as reduced potential for contamination, because no human interaction is required to remove the caps and connect the lines to the spikes. For example, the APD system can include a carriage configured to receive multiple dialysate lines, each having a connector end and a cap. The carriage can be configured to move along a first direction to move the connector ends of the dialysate lines along the first direction, and a cap stripper can be configured to engage caps on the dialysate lines on the carriage. The cap stripper can be configured to move with the carriage along the first direction and also to move in a second direction intersecting the first direction. For example, the carriage can be moved in the first direction toward a cassette of an APD cycler to engage caps on the dialysate lines with caps on spikes on the cassette. The cap stripper can engage the cap (e.g., by moving transversely to the movement of the carriage) and then move with the carriage as it moves away from the cassette to remove the cap from the spike. The carriage can then pull the connector end of the dialysate line from the cap on the cap stripper, which can then be retracted to allow the now-exposed connector end of the dialysate line to engage the exposed spike on the cassette.

[0046] In one embodiment, the carriage can include a plurality of grooves, each receiving a corresponding dialysate line. By positioning the dialysate lines in the corresponding grooves, each line can be more easily individually identified, for example, by reading a barcode or other identifier on the line and controlling the system accordingly. The carriage can be attached to a door of the cycler housing, and the carriage drive can move the carriage along a first direction. In one embodiment, the carriage drive can engage the carriage when the door is moved to a closed position and disengage from the carriage when the door is moved to an open position.

[0047] In one embodiment, the cap stripper can include a plurality of fork-shaped elements positioned to engage corresponding caps on dialysate lines carried by the carriage. The fork-shaped elements retain the caps when removed from the dialysate lines, and each dialysate line cap can itself retain a spike cap. In another embodiment, the cap stripper can include a plurality of rocker arms, each associated with a fork-shaped element. Each rocker arm can be positioned to move to engage a spike cap, for example, to assist in removing the spike cap from the corresponding spike. Each rocker arm can be positioned to engage a corresponding spike cap only when the associated fork-shaped element engages a cap on the dialysate line. In this manner, the cap stripper can avoid engaging or removing spike caps from a cassette in a position where there is no corresponding dialysate line to connect to the spike.

[0048] In another aspect of the invention, a method of connecting fluid lines in a medical infusion fluid delivery system, such as an APD cycler, can include placing a dialysate line and a cassette spike in an enclosed space away from human contact. The dialysate line and / or spike can have their caps removed and the line connected to the spike while in the enclosed space, thus providing a connection and minimizing potential contamination of the connection, for example, by fingers carrying pathogens or other potentially harmful substances. For example, one method according to this aspect of the invention includes providing a plurality of dialysate lines, each having a connector end and a cap; providing a fluid carrying cassette having a plurality of spikes, each covered by a spike cap; surrounding the connector ends of the plurality of dialysate lines with the caps covering the connector ends and surrounding the plurality of spikes with spike caps covering the spikes within a space that prevents human contact with the caps or the spike caps; removing the caps from the connector ends of the plurality of dialysate lines without removing the caps or connector ends from the space; removing the spike caps from the spikes without removing the spike caps or spikes from the space; engaging a cap with a respective one of the spike caps; and fluidly connecting the plurality of connector ends to the corresponding spikes while maintaining the connector ends and spikes within the space and protecting them from human contact.

[0049] In one embodiment, the dialysate line cap and spike cap can be engaged with each other before their removal from the line or spike, and then removed from both the line and spike while still engaged with each other. This technique can simplify cap removal / cap installation and allow for easier storage of the cap.

[0050] In another embodiment, the dialysate line can be disconnected from the spike and the connector end of the line and spike can be reattached to the cap, for example, after treatment is completed.

[0051] In another aspect of the invention, a dialysis machine can include a fluid carrying cassette having a plurality of spikes and a plurality of spike caps covering the respective spikes, a plurality of dialysate lines each having a cap covering a connector end of the respective line, and a cap stripper configured to remove one or more caps from the connector ends of the dialysate lines and to remove one or more spike caps from the spikes on the cassette while the one or more caps are secured to a corresponding one of the spike caps. As discussed above, the dialysis machine can be configured to automatically fluidly connect the connector ends of the dialysate lines to the corresponding spikes after the caps are removed.

[0052] In another aspect of the invention, a dialysis machine, such as an APD system, can include a cassette having a plurality of fluid spikes and a plurality of spike caps covering the respective spikes, a carriage positioned to receive a plurality of dialysate lines, each having a cap covering a connector end of the line, and a cap stripper positioned to engage one or more caps covering the connector ends of the lines. The carriage and cap stripper can be configured to engage the one or more caps on the connector ends of the lines while the one or more caps engage corresponding spike caps covering the spikes on the cassette, remove the spike caps from the spikes, remove the caps from the connector ends of the dialysate lines, and fluidly connect the spikes and the connector ends of the dialysate lines after the caps are removed.

[0053] In another aspect of the invention, the dialysis machine can include a cap stripper positioned to remove one or more caps on the connector ends of the dialysate lines, remove one or more spike caps from the spikes on the fluid carrying cassette, and retain and reattach the caps to the dialysate lines and the spike caps to the spikes on the cassette.

[0054] In another aspect of the invention, a fluid line connection system for a peritoneal dialysis system includes a fluid carrying cassette having a generally planar body with at least one pump chamber and a plurality of fluid flow paths formed as recesses in a first side of the body, a plurality of dialysate line spikes disposed at a first end of the body, the dialysate line spikes fluidly communicating with the at least one pump chamber via at least one fluid path, the spikes disposed so as to be generally flush with the generally planar body of the fluid carrying cassette, and a carriage disposed to receive a plurality of dialysate lines, each dialysate line having a connector end. The carriage is capable of being disposed to automatically fluidly connect the connector ends of the dialysate lines to a corresponding spike.

[0055] In one embodiment, the carriage is positioned to move the dialysate lines and their respective caps along a first direction substantially parallel to the generally planar body of the fluid carrying cassette. A carriage drive for moving the carriage only in the first direction can include a drive element and a pneumatic bladder or screw drive for moving the drive element along the first direction. A cap stripper can be provided that is positioned to remove one or more caps from the connector ends of the dialysate lines and one or more spike caps from the spikes on the cassette while the one or more caps are secured to corresponding ones of the spike caps. In one embodiment, the cap stripper can be positioned to retain and reattach the caps to the dialysate lines and the spike caps to the spikes on the cassette.

[0056] In another aspect of the present invention, a peritoneal dialysis system can include a cycler device having components suitable for controlling the delivery of dialysate to a patient's peritoneal cavity. The cycler device can have a housing enclosing at least some of the components and can include a heater bag receptacle (the term "heater bag" is used herein to refer to any suitable container for heating dialysate, such as a flexible or rigid container made from a polymer, metal, or other suitable material). A cap can be attached to the housing and movable between an open position in which the heater bag can be placed in the heater bag receptacle and a closed position in which the cap covers the heater bag receptacle. Such a configuration can allow for faster or more efficient heating of the dialysate in the heater bag, for example, because heat can be retained by the cap. Additionally, the cap can help prevent human contact with potentially hot surfaces.

[0057] In one embodiment, a dialysis system can include a fluid delivery cassette having a heater bag port attached to a heater bag line, a patient port attached to a patient line, and at least one pump chamber for moving fluid through the patient line and the heater bag line. A heater bag can be attached to the heater bag line and configured for placement in the heater bag receptacle.

[0058] In another embodiment, the system can include an interface (such as a visual display with a touchscreen component) movably mounted on the housing, the interface being movable between a first position in which the interface is received within the heater bag receptacle and a second position in which the interface is located outside the heater bag receptacle (e.g., a position where a user may interact with the interface). In this manner, the interface can be hidden from view when the system is idle, allowing the interface to be protected. Storing the interface in the heater bag receptacle also allows the system to be more compact, at least in the "stored" state.

[0059] In another aspect of the present invention, a dialysis system includes a source of air pressure and / or vacuum suitable for controlling pneumatically operated components of the system; a pneumatically operated component fluidly connected to the source of air pressure and / or vacuum; and a control system that provides air pressure or vacuum to the pneumatically operated component and subsequently isolates the pneumatically operated component from the source of air pressure or vacuum for a substantial period of time before again providing air pressure or vacuum to the pneumatically operated component. Such a configuration can be useful for components that operate relatively infrequently, such as the occlusion configurations described herein. Small movements of some components can cause the component to generate noise that can be perceived as annoying by patients. By isolating a component from the air pressure / vacuum, the component can avoid slight movements caused by fluctuations in the pressure / vacuum source, such as pressure / vacuum draw by other system components. In one embodiment, the substantial period of time can be 5 minutes or more, 1 hour or more, 50% or more of the time required to deliver or remove a volume of dialysate suitable for artificial dialysis from a patient's peritoneal cavity, or other suitable time.

[0060] In another aspect of the invention, a dialysis system includes a source of air pressure and / or vacuum suitable for controlling a pneumatically operated component of the system, the pneumatically operated component fluidly connected to the source of air pressure and / or vacuum, and a control system that supplies air pressure or vacuum to the pneumatically operated component and controls the air pressure or vacuum to reduce noise generated by the pneumatically operated component. For example, the pneumatically operated component can include at least one moving part (such as a pump diaphragm), and the control system reduces the air pressure or vacuum supplied to the pneumatically operated component to slow the movement of the moving part when it stops or changes direction (e.g., the pressure / vacuum can be controlled to slow the movement of the diaphragm before it changes direction). In another embodiment, pulse-width modulation control of a pressure / vacuum supply valve can be used, for example, to reduce noise generated by the moving part of the valve.

[0061] In another aspect of the present invention, a dialysis system includes a source of air pressure and vacuum suitable for controlling pneumatically operated components of the system. A first pneumatically operated component can be fluidly connected to the source of air pressure and / or vacuum and have a first output line for releasing air pressure. A second pneumatically operated component can be fluidly connected to the source of air pressure and / or vacuum and have a second output line for releasing air pressure vacuum. A space, such as that defined by an accumulator, manifold, or sound-insulating chamber, can be fluidly connected to both the first and second output lines. A control system can supply air pressure or vacuum to the pneumatically operated components, such that when the first and second components release pressure / vacuum during operation, the released pressure / vacuum can be received in a common space (e.g., a manifold). In some situations, gas under positive pressure released by a component can be balanced by negative pressure released by another component, thus reducing generated noise.

[0062] In another aspect of the present invention, a peritoneal dialysis system includes a fluid delivery cassette fluidly connected to a patient's peritoneal cavity and having a patient line leading from the peritoneal cavity, the cassette including at least one pump chamber for moving dialysate in the patient line. A cycler device can be configured to receive and interact with the fluid delivery cassette and to cause the at least one pump chamber to move dialysate in the patient line. The cycler can include a control system configured to control the at least one pump chamber to operate in a preparatory operation to push dialysate into the patient line to remove any air in the patient line, and can be configured to interact with two types of fluid delivery cassettes that differ in the volume of the patient line connected to the cassette body. A first type of cassette may have a relatively small volume patient line (e.g., for pediatric use) and a second type of cassette may have a relatively large volume patient line (e.g., for adult use), and the control system may detect whether a cassette received by the cycler is the first or second type and adjust the cycler operation accordingly.

[0063] In one embodiment, the control system can detect whether a cassette received by the cycler is of the first or second type by determining the volume of the patient line during preparation and adjust the volume of fluid moved through the cassette during operation of the system. In another embodiment, indicia such as a barcode on the cassette can be detected by the cycler to cause the cycler to adjust pump operation based on the type of cassette.

[0064] In another aspect of the invention, a dialysis machine includes a fluid-carrying cassette having a plurality of spikes and at least one pump chamber for moving fluid in the spikes, a plurality of dialysate lines each engaging a respective spike on the cassette, and a control system that reads indicia on each of the dialysate lines to determine the type of each dialysate line. The control system can adjust pumping or other cycler operations based on the identity of one or more of the dialysate lines. For example, a dialysate line may be identified as a drain sampling line, and pumping can be adjusted to direct spent dialysate from the patient to the drain sampling line during a drain cycle.

[0065] In another aspect of the invention, a method for automatically recovering from a tilt condition in a dialysis system can include: (A) detecting a tilt angle of at least a portion of a dialysis system, the portion of the dialysis system comprising a mechanism for performing dialysis treatment; (B) determining that a tilt condition exists where the tilt angle exceeds a predetermined threshold; (C) pausing dialysis treatment in response to (B); (D) monitoring the tilt angle while dialysis treatment is paused; (E) determining that the tilt condition no longer exists; and (F) automatically resuming dialysis treatment in response to (E).

[0066] In another aspect of the present invention, a patient data interface for a dialysis system includes a device port having a recess in at least a portion of a chassis of the dialysis system and a first connector disposed within the recess. The patient data storage device can include a housing and a second connector coupled to the housing, the second connector configured to be selectively coupled to the first connector. The recess can have a first shape and the housing can have a second shape corresponding to the first shape, such that when the first and second connectors are coupled, the housing of the patient data storage device is at least partially received within the recess. The first and second shapes can be irregular, and the patient data storage device can have a verification code readable by the dialysis system to verify that the patient data storage device is of the expected type and / or manufacturer.

[0067] In another aspect of the invention, a method of providing peritoneal dialysis includes supplying or withdrawing dialysate to or from a patient's peritoneal cavity at a first pressure and adjusting the pressure at which the dialysate is supplied or withdrawn to minimize the patient's sensation of dialysate movement. In one embodiment, the pressure can be adjusted during the same induction or empty cycle of a peritoneal dialysis treatment and / or within different induction or empty cycles of a peritoneal dialysis treatment. For example, when withdrawing dialysate from a patient, the pressure at which the dialysate is withdrawn can be reduced when the volume of dialysate remaining in the peritoneal cavity drops below a threshold volume. Reducing the pressure (negative pressure or vacuum) near the end of the withdrawal cycle can reduce the sensation the patient may experience during dialysate withdrawal.

[0068] In another aspect of the present invention, a method of providing peritoneal dialysis includes using a reusable cycler device to supply a first dialysate to a patient's peritoneal cavity during a first treatment of peritoneal dialysis, and using the reusable cycler device to supply a second dialysate to the patient's peritoneal cavity during a second treatment of peritoneal dialysis immediately after the first treatment, the second dialysate having a different chemical composition than the first dialysate. The different dialysates can be produced by mixing liquid materials from two or more dialysate containers connected to the cycler (e.g., via cassettes attached to the cycler). The dialysate containers can be automatically identified by the cycler, for example, by reading barcodes, RFID tags, or other indicia.

[0069] In another aspect of the invention, a medical infusion system includes a housing enclosing at least some of the system's components, and a control surface attached to the housing and constructed and arranged to control operation of a fluid carrying cassette removably attachable to the housing. The control surface can have a plurality of movable portions arranged to control fluid pumping and valving of the cassette, and at least one of the movable portions can have an associated vacuum port arranged to draw fluid from an area proximate the movable portion.

[0070] In one embodiment, the control surface comprises a sheet of resilient polymeric material, and each movable portion can have an associated vacuum port. In another embodiment, the cassette comprises a membrane that can be positioned adjacent to the control surface, and the vacuum port is positioned to remove fluid from the space between the membrane and the control surface. A liquid sensor can be positioned to detect liquid being drawn into the vacuum port, for example, if the membrane ruptures, allowing fluid to escape from the cassette.

[0071] In another aspect of the invention, the volume of fluid moved by a pump, such as a pump in an APD system, can be determined based on pressure measurements and a known chamber volume and / or in-line volume, but not based on direct measurement of fluid by flow meter, weight, etc. In one embodiment, the volume of a pump chamber having a moving element that changes the volume of the pump chamber can be determined by measuring the pressure in the pump chamber and the pressure in the reference chamber while both the pump chamber and the reference chamber are isolated from each other, and the chamber pressures can be equalized after the two chambers are fluidly connected. In one embodiment, pressure equalization can be assumed to occur adiabatically; for example, a mathematical model of the system based on an adiabatic pressure equalization process can be used to determine the pump chamber volume. In another embodiment, the pressure measured after the two chambers are fluidly connected can be measured at a time before complete equalization occurs; therefore, the pressures for the pump chamber and the reference chamber measured after the two chambers are fluidly connected may not be equal but can still be used to determine the pump chamber volume. This approach can reduce the time between the initial and final pressure measurements, thereby reducing the time over which heat transfer occurs and reducing errors that may be introduced given the adiabatic model used to determine the pump chamber volume.

[0072] In one aspect of the invention, a method for determining a volume of fluid displaced by a pump includes measuring a first pressure in a pump control chamber when the pump control chamber is isolated from a reference chamber. The pump control chamber can have a volume that varies at least in part based on operation of a portion of the pump, such as a pump membrane or diaphragm. A second pressure can be measured relative to the reference chamber when the reference chamber is isolated from the pump control chamber. The reference chamber can have a known volume. A third pressure associated with the pump control chamber can be measured after fluidly connecting the reference chamber and the pump control chamber, which measurement can occur before substantial pressure equalization occurs between the pump control chamber and the reference chamber. Similarly, a fourth pressure associated with the reference chamber can be measured after fluidly connecting the reference chamber and the pump control chamber, which measurement can occur before substantial pressure equalization occurs between the pump control chamber and the reference chamber. The volume of the pump control chamber can be determined based on the first, second, third, and fourth measured pressures.

[0073] In one embodiment, the third and fourth pressures are measured at approximately the same time, and the third and fourth pressures are not substantially equal to each other. For example, once the pump control chamber and the reference chamber are fluidly connected, pressure equalization within the pump control chamber and the reference chamber can occur after an equalization period, but the third and fourth pressures can be measured at a time after the pump control chamber and the reference chamber are fluidly connected, approximately 10% to 50% of the equalization period. In this manner, the third and fourth pressures can be measured long before the pressures in the two chambers are completely equalized. In another embodiment, the third and fourth pressures can be measured at a time when the pressures in the two chambers reach approximately 50% to 70% equalization, e.g., when the pressures in the two chambers change from an initial value that is within approximately 50% to 70% of the equalization pressure value. In this manner, the time between the measurements of the first and second pressures and the measurements of the third and fourth pressures can be minimized.

[0074] In another embodiment, the model for determining the volume of the pump control chamber can incorporate the assumption that an adiabatic system exists from the time the first and second pressures are measured relative to the isolated pump control chamber and reference chamber to the time the third and fourth pressures are measured.

[0075] Determining the volume of fluid displaced by the pump can include measuring the first, second, third, and fourth pressures, and the determining can be performed for two different positions of the pump membrane to determine two different volumes for the pump control chamber, the difference between the two different volumes representing the volume of fluid delivered by the pump.

[0076] As mentioned above, this aspect of the invention can be used in any suitable system, such as a system in which the pump is part of a disposable cassette and the pump control room is part of a dialysis machine used in a dialysis treatment.

[0077] In one embodiment, the first and / or second pressures can be selected from the multiple pressure measurements to coincide with the time when the pressure in the pump control chamber or reference chamber (as appropriate) first begins to change from a previously stable value. For example, this time can be identified based on determining when the best fit line for multiple consecutive sets of measured pressures first deviates from a constant slope. This approach can help identify the initial pressures in the pump control chamber and reference chamber as late as possible while reducing errors in pump volume determination.

[0078] In another embodiment, a technique can be used to identify optimal times at which the third and fourth pressures are measured. For example, multiple pressure values ​​for the pump control chamber can be measured after the pump control chamber and the reference chamber are fluidly connected, and multiple changes in volume can be determined for the pump control chamber based on the multiple pressure values ​​for the pump control chamber. Each of the multiple changes in volume can correspond to a specific time and pressure value measured for the pump chamber. In this case, the change in volume is due to the movement of a virtual piston present in a valve or other component that originally separated the pump control chamber and the reference chamber, but which moves an opening in the valve or other component. In this way, the pump chamber does not actually change size or volume; rather, the change in volume is a virtual condition due to the pressures in the pump chamber and the reference chamber, which were initially different from each other. Similarly, multiple pressure values ​​for the reference chamber can be measured after the pump control chamber and the reference chamber are fluidly connected, and multiple changes in volume for the reference chamber can be determined based on the multiple pressure values ​​for the reference chamber. Each of the multiple volume changes can correspond to a pressure value measured relative to a specific time point and the reference chamber, and, like the volume change in the pump chamber, is a result of the movement of the virtual piston. Multiple difference values ​​between the volume changes in the pump control chamber and the reference chamber can be determined, with each difference value determined corresponding to the volume change in the pump control chamber and the volume change in the reference chamber. That is, pairs of volume changes for which difference values ​​are determined correspond to the same or substantially the same time point. The difference values ​​can be analyzed, and the smallest difference value (or a difference value below a desired threshold) can indicate the time point at which the third and fourth pressures should be measured. In this way, the third and fourth pressure values ​​can be identified as equal to the pump control chamber pressure value and the reference chamber pressure value, respectively, and correspond to the smallest or below-threshold difference value.

[0079] In another embodiment, the measured pressure is the pressure of gas in the pump control chamber and the reference chamber, the equalization of pressure in the pump control chamber and the reference chamber is assumed to occur adiabatically, the equalization of pressure between the pump control chamber and the reference chamber is assumed to include equal but opposite changes in volume of gas in the pump control chamber and the reference chamber, and the volume of gas in the reference chamber at the fourth pressure measurement is calculated from the known volume of the reference chamber and the second and fourth pressures. The change in volume of gas in the reference chamber can be assumed to be the difference between the known volume of the reference chamber and the calculated volume of gas in the reference chamber at the fourth pressure measurement. The change in volume of gas in the pump control chamber can also be assumed to be the difference between the initial volume of the pump control chamber and the volume of gas in the pump control chamber at the third pressure measurement, and the change in volume of gas in the pump control chamber is equal but opposite to the change in volume of gas in the reference chamber.

[0080] In another aspect of the invention, a method for determining a volume of fluid displaced by a pump includes providing a fluid pumping apparatus having a pump chamber separated from a pump control chamber by a movable membrane and a reference chamber fluidly connectable to the pump control chamber; adjusting a first pressure in the pump control chamber to operate the membrane, thereby displacing fluid in the pump chamber; isolating the reference chamber from the pump control chamber and establishing a second pressure in the reference chamber that is different from the pressure in the pump control chamber; fluidly connecting the reference chamber and the pump control chamber to initiate pressure equalization in the pump control chamber and the reference chamber; and determining a volume of the pump control chamber based on the first and second pressures and an assumption that the pressures in the pump control chamber and the reference chamber initiate adiabatic equalization.

[0081] In one embodiment, third and fourth pressures of the pump control chamber and the reference chamber, respectively, can be measured after fluidly connecting the reference chamber and the pump control chamber, and the third and fourth pressures can be used to determine the volume of the pump control chamber. The third and fourth pressures can be substantially unequal to one another. As above, the adjusting, isolating, fluidly connecting, and determining steps can be repeated, and a difference between the two determined volumes for the pump control chamber can be determined, with the difference representing the volume of fluid delivered by the pump.

[0082] In another embodiment, the pump is part of a disposable cassette and the pump control room is part of a dialysis machine used in the dialysis treatment. In another aspect of the present invention, a medical infusion system includes a pump control chamber; a control surface associated with the pump control chamber, at least a portion of which is movable in response to pressure changes within the pump control chamber; a fluid delivery cassette having at least one pump chamber disposed adjacent to the control surface and arranged such that fluid within the at least one pump chamber moves in response to operation of a portion of the control surface; a reference chamber fluidly connectable to the pump control chamber; and a control system arranged to regulate the pressure within the pump control chamber, thereby controlling movement of fluid within the pump chamber of the fluid delivery cassette. The control system can be configured to measure a first pressure in the pump control chamber when the pump control chamber is isolated from the reference chamber, measure a second pressure in the reference chamber when the reference chamber is isolated from the pump control chamber, fluidly connect the pump control chamber and the reference chamber, and measure third and fourth pressures associated with the pump control chamber and the reference chamber, respectively, after fluidly connecting the reference chamber and the pump control chamber, and determine the volume of the pump control chamber based on the first, second, third, and fourth measured pressures and a mathematical model that defines pressure equalization in the pump control chamber and the reference chamber that occurs adiabatically when the pump control chamber and the reference chamber are fluidly connected.

[0083] In one embodiment, the third and fourth pressures are not substantially equal to one another, for example, the third and fourth pressures can be measured prior to substantial pressure equalization in the pump control chamber and the reference chamber.

[0084] In another aspect of the invention, a method for determining a volume of fluid displaced by a pump includes measuring a first pressure in a pump control chamber when the pump control chamber is isolated from a reference chamber, the pump control chamber having a volume that varies at least in part based on operation of a portion of the pump; measuring a second pressure in the reference chamber when the reference chamber is isolated from the pump control chamber; measuring a third pressure associated with both the pump control chamber and the reference chamber after fluidly connecting the reference chamber and the pump control chamber; and determining a volume of the pump control chamber based on the first, second, and third measured pressures.

[0085] In one embodiment, the third pressure can be measured after full pressure equalization of the pump control chamber and the reference chamber is completed. In one embodiment, the model used to determine the pump chamber volume can assume an adiabatic system in the pressure equalization between the pump chamber and the reference chamber.

[0086] In one aspect of the invention, a method for determining the presence of air in a pump chamber includes measuring the pressure in the pump control chamber when the pump control chamber is isolated from a reference chamber, the pump control chamber having a known volume and separated by a membrane from a pump chamber at least partially filled with liquid; measuring the pressure in the reference chamber when the reference chamber is isolated from the pump control chamber, the reference chamber having a known volume; measuring the pressure after fluidly connecting the reference chamber and the pump control chamber and prior to the time when the pressures in the two chambers are equalized; and determining the presence or absence of air bubbles in the pump chamber based on the measured pressure and the known volume.

[0087] In one embodiment, the model used to determine the presence or absence of bubbles assumes an adiabatic system from the point at which pressure is measured for the separated pump control and reference chambers until a point after the two chambers are fluidly connected. In another embodiment, the pressure in the pump control chamber is measured by a membrane that is pulled toward the wall of the pump control chamber.

[0088] In another aspect of the present invention, an automated peritoneal dialysis system includes a reusable cycler constructed and arranged to be coupled to a disposable fluid delivery cassette having at least one pump chamber. The disposable fluid delivery cassette can be configured to be fluidly connected to a patient's peritoneum via a first extrusion tube and to a second source and / or destination (e.g., a dialysate container line) via a second extrusion tube. An occlusion can be configured and arranged within the cycler to selectively occlude the first extrusion tube while leaving the second extrusion tube unoccluded. In one embodiment, the occlusion can occlude multiple extrusion tubes, such as a patient line, a drain line, and / or a heater bag line. The cassette can have a generally planar body with at least one pump chamber formed as a recess in a first side of the body and multiple fluid paths for fluids, a patient line port located at a first end of the body arranged for connection to the first extrusion tube, and a dialysate line port located at a second end of the body opposite the first end and arranged for connection to the second extrusion tube. The occlusions can be constructed and arranged within the cycler to selectively occlude the first and third extrusion tubes (eg, for delivery) while leaving the second extrusion tube unoccluded.

[0089] In another embodiment, the occlusion includes first and second opposing occlusion members pivotally connected to one another, a tube contacting member connected to at least one of the first and second occlusion members or comprising at least a portion of at least one of the first and second occlusion members, and a force actuator constructed and arranged to apply a force to at least one of the first and second occlusion members. Application of force by the force actuator can move the tube contacting member between a tube occluding and an open position. The occlusion can include a release member constructed and arranged to allow an operator to manually move the tube contacting member from the tube occluding position to the open position even when no force is applied to the occlusion member by the force actuator. The force actuator can apply sufficient force to bend both the first and second occlusion members, such that upon application of force by the force actuator to bend the first and second occlusion members, the tube contacting member can be moved between a tube occluding and an open position. The occlusion member can be a leaf spring pivotally connected to opposite first and second ends, and the tube contacting member can be a pinch head connected to the leaf spring at a first end, while the second end of the leaf spring can be attached directly or indirectly to a housing to which the occlusion is connected. In one embodiment, the force actuator comprises an inflatable bladder disposed between the first and second occlusion members. The force actuator can increase the distance between the first and second occlusion members in the region where they face, thereby moving the tube contacting member between a tube-occluding and an open position. In one embodiment, the force actuator can bend one or both of the occlusion members to move the tube contacting member from the tube-occluding position to the open position.

[0090] Various aspects of the present invention are described above and below with reference to exemplary embodiments. It should be understood that various aspects of the present invention can be used alone and / or in any suitable combination with other aspects of the present invention. For example, the pump volume determination features described herein can be used in a liquid transport cassette having the specific features described or any other suitable pump configuration.

[0091] Aspects of the present invention are described below with reference to exemplary embodiments illustrated at least in part in the following figures, in which like numerals refer to like elements. [Brief explanation of the drawings]

[0092] [Figure 1] 1 is a schematic diagram of an automated peritoneal dialysis (APD) system incorporating one or more aspects of the present invention. [Figure 1A] 2 is a schematic diagram illustrating an alternative configuration to the dialysate supply set shown in FIG. 1. [Figure 2] Schematic diagram of an exemplary set for use with the APD system of FIG. [Figure 3] FIG. 2 is an exploded perspective view of the cassette according to the first embodiment. [Figure 4] 4 is a cross-sectional view of the cassette taken along line 4-4 in FIG. 3. [Figure 5] FIG. 1 is a perspective view of a vacuum mold that may be used to form a membrane having a pre-formed pumping chamber portion in an exemplary embodiment. [Figure 6] FIG. 4 is a front view of the cassette body of FIG. 3. [Figure 7] 10A and 10B are front views of a cassette body including two different spacer arrangements in an exemplary embodiment. [Figure 8] FIG. 4 is a rear perspective view of the cassette body of FIG. 3. [Figure 9] FIG. 4 is a rear view of the cassette body of FIG. 3. [Figure 9-1A] FIG. 1 is a front perspective view of a typical configuration of a patient line status detector or fluid level detector. [Figure 9-1B] FIG. 1 is a rear perspective view of a patient line status or level detector. [Figure 9-2] Layout perspective of three LEDs and an optical detector surface mounted on a printed circuit board. [Figure 9-3] Top view of the three LEDs and optical detector mounted on the detector circuit board. [Figure 9-4] An exploded perspective view of the detector of Figure 9-1 showing the printed circuit board and transparent or translucent plastic insert. [Figure 9-5] FIG. 10 is a perspective view of an alternative configuration of a liquid level detector. [Figure 9-6] FIG. 1 is a front perspective view of an unloaded organizer (absent any dialysate lines). [Figure 9-7] Rear view of the organizer in Figure 9-6. [Figure 9-8] FIG. 1 is a perspective view of an organizer with multiple dialysate lines, patient lines, and drain lines. [Figure 9-9] Perspective view of the organizer clip. [Figure 9-10] Perspective view of the organizer clip receiver. [Figure 9-11] A perspective view of the door latch sensor assembly associated with the cycler. [Figure 9-11a] Cross-sectional view of the door latch sensor assembly of Figures 9-11. [Figure 9-12] Graph showing the ability of the liquid level detector of Figure 9-1 to identify primed and unprimed patient lines. [Figure 9-12A] Graph showing the results of the sample calibration process for six cyclers. [Figure 9-13] 10 is a graph showing measurements collected by an optical sensor comparing liquid detection using angled LEDs versus orthogonally positioned LEDs. [Figure 9-14] Graph showing the ability of the liquid level detector of FIG. 9-1 to identify the presence and absence of a tube compartment within the detector. [Figure 10] FIG. 2 is a perspective view of the APD system of FIG. 1 (with the cycler door in the open position). [Figure 11] 11 is a perspective view of the inside of the cycler door in FIG. 10. FIG. [Figure 11-1] FIG. 2 is a perspective view of a carriage according to the first embodiment. [Figure 11-2] FIG. 11-2 is an enlarged perspective view of the dialysate line mounted on the carriage of FIG. 11-1. [Figure 11-3] FIG. [Figure 11-4] FIG. 1 is a perspective view of a carriage drive assembly with an Auto ID camera mounted on an Auto ID camera board. [Figure 11-5] FIG. 10 is a perspective view of an embodiment of a stripper element of a cap stripper. [Figure 11-6] 11-4 is a front perspective view of the carriage drive assembly of FIG. 11-4 showing the position of the stripper element of FIG. 11-5 within the carriage drive assembly. [Figure 11-7a] 11-5 is a perspective view of a portion of the stripper element (with spike caps in place). [Figure 11-7b] 11-5 is a perspective view of a portion of the stripper element of FIG. 11-5 (with the dialysate line cap positioned over the spike cap). [Figure 11-7c] 11-5 is a perspective view of a portion of the stripper element of FIG. 11-5 (showing the sensor element and rocker arm without the spike cap). [Figure 12] FIG. 2 is a right-front perspective view of the carriage drive assembly and cap stripper in the first embodiment. [Figure 13] FIG. 13 is a left-front perspective view of the carriage drive assembly and cap stripper of FIG. [Figure 14] FIG. 13 is a partial rear view of the carriage drive assembly of FIG. 12; [Figure 15] FIG. 10 is a rear perspective view of the carriage drive assembly in the second exemplary embodiment. [Figure 16] FIG. 16 is a left rear perspective view of the carriage drive assembly and cap stripper of FIG. [Figure 17] FIG. 10 is a left-front perspective view of the cap stripper element in an exemplary embodiment. [Figure 18] 18 is a right-front perspective view of the cap stripper element of FIG. 17; [Figure 19] FIG. 18 is a front view of the cap stripper element of FIG. 17. [Figure 20] 20 is a cross-sectional view taken along line 20-20 in FIG. 19. [Figure 21] 21 is a cross-sectional view taken along line 21-21 in FIG. 19. [Figure 22] 22 is a cross-sectional view taken along line 22-22 in FIG. 19. [Figure 23] FIG. 10 is an exploded close-up view of the connector end of the dialysate line in an exemplary embodiment. [Figure 24] Schematic diagram of the cassette and dialysate lines installed in the cycler in Figure 10. [Figure 25] 11A and 11B are schematic diagrams of the cassette and dialysate lines after placement of the cycler doors in their respective positions in FIG. 10 . [Figure 26] Schematic of the cassette and dialysate lines after the cycler door is closed. [Figure 27] Schematic of the dialysate line engaging the spike cap. [Figure 28] Schematic of the cap stripper engaging the spike cap and dialysate line cap. [Figure 29] Schematic of the dialysate line with cap and spike cap attached after movement away from the cassette. [Figure 30] Schematic of the dialysate line cap and the dialysate line after movement away from the spike cap. [Figure 31] Schematic of the cap stripper retracting along with the dialysate line cap and spike cap. [Figure 32] Schematic of the dialysate line engaging the spike on the cassette. [Figure 33] FIG. 10 is a cross-sectional view of a cassette with five stages of dialysate line connection operation shown relative to the corresponding spikes on the cassette. [Figure 34] FIG. 10 is a rear view of the cassette in another exemplary embodiment including a different arrangement for the rear side of the cassette adjacent the pump chamber. [Figure 35]10 is an end view of the spike of the cassette in the exemplary embodiment; [Figure 35A] FIG. 10 is a perspective view of another embodiment of a spike for the cassette. [Figure 35B] 35A shows an embodiment of a spike cap configured to fit onto the spike shown in FIG. 35A. [Figure 35C] Cross section of the spike cap shown in Figure 35B. [Figure 36] FIG. 11 is a front view of the control surface of the cycler for interaction with the cassette in the embodiment of FIG. 10. [Figure 36A] FIG. 10 is a front view and selected cross-sectional views of an embodiment of a control surface of a cycler. [Figure 37] Exploded view of the assembly for the interface in Figure 36. [Figure 37A] 27 is an exploded view of an integrated pressure distribution module or assembly 2700 suitable for use in a fluid flow control device for operating a pumping cassette and as a pressure distribution manifold 172 and interface block 170 of a cycler 14. FIG. [Figure 37B] An exploded perspective view of an integrated module 2700 with a pneumatic manifold or block, ports for supply pressure, pneumatic control valves, pressure sensors, pressure supply or junction block, and a control surface or actuator with a flexible membrane for actuating the pump and an area containing a valve on the pumping cassette. [Figure 37C] Schematic of the pneumatic circuits in the integrated manifold 2700 and the pneumatic elements outside the manifold. [Figure 38] FIG. 10 is an exploded perspective view of an exemplary embodiment of an occlusion. [Figure 39] FIG. 39 is a partially exploded perspective view of the closure of FIG. 38. [Figure 40] FIG. 39 is a top view of the closure of FIG. 38 with the bladder in a deflated state. [Figure 41] FIG. 39 is a top view of the closure of FIG. 38 with the bladder in an inflated state. [Figure 42] 1 is a schematic diagram of the pump chambers and associated control components and inflow / outflow paths of the cassette in an exemplary embodiment. [Figure 43] 43 is a plot of exemplary pressure values ​​for the control and reference chambers from a time before valve X2 is opened to a time some time after valve X2 is opened for the embodiment of FIG. 42. [Figure 44] 11 is a perspective view of the internal compartment of the cycler of FIG. 10 (with the top of the housing removed). [Figure 45] 1 is a schematic block diagram illustrating an exemplary implementation of a control system for an APD system. [Figure 45A] 3 is a block diagram illustrating one configuration of an automation computer 300, a UI computer 302, and a hardware interface processor 310. FIG. [Figure 45B] A block diagram showing the connections between the hardware interface 310, various sensors, pneumatic valves, bag heaters and automation computer 300. [Figure 46] Figure 45 is a schematic block diagram of exemplary software subsystems of the user interface computer and automation computer for the control system. [Figure 47] 3 is a flowchart illustrating the flow of information between various subsystems and processes of the APD system in an example embodiment. [Figure 48] 47 is a schematic diagram illustrating the operation of the treatment subsystem of FIG. 46. [Figure 49] 1 is a sequence diagram illustrating a typical interaction of treatment module processes during the initial introduction and dialysis portion of treatment. [Figure 49-1] 5 is a schematic diagram of an exemplary embodiment of a dialysate heater system 500. [Figure 49-2] FIG. 2 is a schematic block diagram of the software aspects of the heater control subsystem. [Figure 49-3] A control scheme using tandem nested control loops. [Figure 49-4] Schematic diagram of one embodiment of the inner loop controller 512 (heater pan controller). [Figure 49-5] Schematic diagram of outer loop controller 514 (button temperature sensor controller). [Figure 49-6] Schematic block diagram of the heater pan and heater bag in the control volume analysis. [Figure 49-7] 10 is a graph illustrating the performance of a dialysate heater system of the disclosed embodiments operating under normal conditions. [Figure 49-8] Graph showing the performance of the dialysate heater system operated in a high temperature environment where the ambient temperature is 35°C. [Figure 49-9] Graph showing the performance of a dialysate heater system operated in a cold environment when the ambient temperature is 10 °C and the source fluid is 5 °C. [Figure 49-10] FIG. 2 is a block diagram illustrating one embodiment of a heater circuit. [Figure 49-11] FIG. 1 is a block diagram illustrating a dual voltage heater circuit that varies the resistance of the heater. [Figure 49-12] FIG. 10 is a block diagram illustrating another example of a heater circuit that varies the effective resistance of the heater by varying the heater configuration. [Figure 49-13] FIG. 1 is a circuit diagram of an embodiment of the present invention. [Figure 49-14] 10 is a flow chart illustrating a method for involving a user in properly configuring a heater element for an available AC voltage. [Figure 49-15] 4 is a flow chart illustrating how AC voltage values ​​are stored in the memory of the control system. [Figure 50] A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 51] A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 52] A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 53]A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 54] A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 55] A typical screen view of the warnings and alarms that can be displayed on the touchscreen user interface for an APD system. [Figure 56] 1 illustrates the states and operations of components for error condition detection and recovery in an exemplary embodiment. [Figure 57] Figure 1 shows a typical module of a UI view subsystem for an APD system. [Figure 58] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 59] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 60] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 61] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 62]10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 63] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 64] 10 illustrates exemplary user interface screens that provide user information and accept user input in exemplary embodiments regarding system setup, treatment status, display settings, remote assistance, and parameter settings. [Figure 65] A perspective view showing a typical patient data key and associated ports for transferring patient data to and from an APD system. [Figure 65A] FIG. 10 is a perspective view showing a patient data key with an alternative housing configuration. [Figure 66] Graph showing pressure over time during a supply stroke and subsequent FMS measurements. [Figure 67] Cycla's adaptive tidal mode graph when in CCPD mode. [Figure 68] Graph showing how the Cycla can handle incomplete derivations that do not reach the maximum residual IPV 710. [Figure 69] Graph showing that TPD can be subjected to a modified cycle mode of treatment. [Figure 70] Graph showing how adaptive tidal treatment modes can be employed during standard tidal treatment. DETAILED DESCRIPTION OF THE INVENTION

[0093] Although embodiments of the present invention are described with respect to peritoneal dialysis systems, certain embodiments of the present invention can be used in other medical applications, including infusion systems such as intravenous infusion systems or extracorporeal blood flow systems, irrigation and / or fluid exchange systems for the stomach, intestines, bladder, pleural cavity, or other body or organ cavities. Thus, embodiments of the present invention are not limited to use with peritoneal dialysis in particular or dialysis in general. [APD System] FIG. 1 illustrates an automated peritoneal dialysis (APD) system 10 that can incorporate one or more aspects of the present invention. As shown in FIG. 1 , for example, in this exemplary embodiment, system 10 includes a dialysate supply set 12 (which, in some embodiments, can be disposable), a cycler 14 that interacts with supply set 12 to pump fluid supplied by a dialysate container 20 (e.g., a bag), and a control system 16 (e.g., a programmed computer or other data processor, computer memory, an interface for providing information to and receiving input from a user or other device, one or more sensors, actuators, relays, pneumatic pumps, tanks, power sources, and / or other suitable components) that manages the process for performing the APD treatment. While only a few buttons for receiving user control inputs are shown in FIG. 1 , more details regarding the control system components are provided below. In this exemplary embodiment, cycler 14 and control system 16 are associated with a common housing 82, but can be associated with two or more housings and / or can be separate from each other. The cycler 14 can have a compact footprint suitable for operation on a tabletop or other relatively small surface commonly found in the home. The cycler 14 can be lightweight and portable, for example, carried by hand via handles on the opposing side of the housing 82.

[0094] Set 12 in this embodiment is intended to be a single-use, disposable item, but may alternatively have one or more reusable components, or may be reusable in its entirety. Before initiating each APD therapy session, a user associates set 12 with cycler 14, which interacts with cassette 24 to pump and control fluid flow in various lines of set 12, for example, by installing cassette 24 in front door 141 of cycler 14. For example, dialysate can be pumped to and from a patient to achieve APD. After therapy, a user can remove all or some of the components of set 12 from cycler 14.

[0095] Prior to use, a user can connect the patient line 34 of the set 12 to their indwelling peritoneal catheter (not shown) at connection 36, as is known in the art. In one embodiment, the cycler 14 can be configured to operate with one or more different types of cassettes 24, such as those having patient lines 34 of various sizes. For example, the cycler 14 can be arranged to operate with a first type of cassette with patient lines 34 sized for use with adult patients and a second type of cassette with patient lines 34 sized for use with infants or children. The pediatric patient lines 34 can be shorter and have a smaller inner diameter than adult lines to minimize line volume, allowing for a more controlled delivery of dialysate and helping to prevent the return of relatively large volumes of spent dialysate to the pediatric patient when the set 12 is used for successive drain and inlet cycles. The heater bag 22, connected to the cassette 24 by line 26, can be placed on a heater container receiving portion (in this case, a tray) 142 of the cycler 14. The cycler 14 can pump fresh dialysate (via the cassette 24) into the heater bag 22, where it is heated by the heater tray 142, e.g., by electrical resistance heating elements associated with the tray 142, to a temperature of approximately 37°C. The heated dialysate can be provided to the patient from the heater bag 22 via the cassette 24 and the patient line 34. In an alternative embodiment, the dialysate can be heated on its way to the patient by passing the dialysate through tubing that contacts the heater tray 142 or an in-line fluid heater (which can be provided within the cassette 24) on its way to and from the cassette 24. Spent dialysate can be pumped from the patient via the patient line 34 to the cassette 24 and then to the outlet line 28, which can include one or more clamps to regulate flow through one or more branches of the outlet line 28.In this exemplary embodiment, the outlet line 28 can include a connector 39 for connecting the outlet line 28 to a dedicated outlet receptacle and an outlet sample port 282 for taking a sample of used dialysate for testing or other analysis. A user can also attach lines 30 to one or more containers 20 within the door 141. The lines 30 can also be connected to a continuous or real-time dialysate preparation system (lines 26, 28, 30, and 34 can include flexible tubing and / or appropriate connectors and other components, such as pinch valves, as desired). The container 20 can contain sterile peritoneal dialysis fluid or other materials for introduction (e.g., materials used by the cycler 14 to create dialysate by mixing with water or various types of dialysate). The lines 30 can be connected to a spike 160 on the cassette 24, which is shown in FIG. 1 covered by a removable cap. In one aspect of the invention, described in more detail below, the cycler 14 can automatically remove the caps from one or more spikes 160 of the cassette 24 and connect the lines 30 of the dialysate container 20 to each spike 160. This feature can help reduce the chance of contact of non-sterile items with the spikes 160, thereby reducing the possibility of infection or contamination.

[0096] In another embodiment, the dialysate supply set 12a may not have a cassette spike 160. Alternatively, as shown in FIG. 1A, one or more dialysate lines 30 may be permanently attached to the inlet port of the cassette 24. In this case, the dialysate lines 30 may each have a spike connector 35 (with a cap) for manual connection to a dialysate container or bag 20.

[0097] With the various connections made, the control system 16 can coordinate the cycler 14 through a series of input, dwell, and / or drain cycles typical of APD treatment. For example, during an input phase, the cycler 14 can pump dialysate (via cassette 24) from one or more containers 20 (or other dialysate sources) to a heater bag 22 for heating. The cycler 14 can then pump the heated dialysate from the heater bag 22 through the cassette 24 and into the patient's peritoneal cavity via a patient line 34. Following the dwell phase, the cycler 14 can begin a drain phase in which the cycler 14 pumps spent dialysate from the patient via line 34 (again via cassette 24) and discharges the spent dialysate via a drain line 28 to a nearby drain (not shown).

[0098] The cycler 14 does not necessarily require the dialysate container 20 and / or heater bag 22 to be positioned at a defined head height above the cycler 14, for example, because the cycler 14 is not necessarily a gravity-flow system. Alternatively, the cycler 14 can mimic gravity flow of dialysate or appropriately control gravity flow when the patient is above or below the cycler 14, even if the dialysate source container 20 is above, below, or at the same height as the cycler 14. For example, the cycler 14 can mimic a fixed head height during a given treatment, or the cycler 14 can vary the effective head height to increase or decrease the pressure applied to the dialysate during treatment. The cycler 14 can also adjust the flow rate of the dialysate. In one aspect of the present invention, the cycler 14 can adjust the pressure and / or flow rate of the dialysate as it is delivered to or withdrawn from the patient to reduce the patient's sensation of an inlet or outlet action. Such adjustments may occur during a single intake and / or drain cycle, or may be adjusted across different intake and / or drain cycles. In one embodiment, the cycler 14 may gradually reduce the pressure used to draw spent dialysate from the patient near the end of the drain operation. Because the cycler 14 is capable of establishing an artificial head height, it interacts with a particular physiology and has the flexibility to fit that physiology or change the relative height of the patient. [cassette] In one aspect of the present invention, the cassette 24 can include patient and drain lines that can be separately occluded relative to the dialysate supply line. That is, safe critical flow to and from the patient line can be controlled, for example, by pinching the lines to stop flow, without having to occlude flow through one or more dialysate supply lines. This feature may allow for a simplified occlusion device, as occlusion can be performed on only two lines, as opposed to occluding other lines, which has little or no effect on patient safety. For example, the patient and drain lines can be occluded when the patient or drain line connections are disconnected. However, the dialysate supply and / or heater bag lines can remain open to flow, thereby preparing the cycler 14 for the next dialysis cycle. For example, separate occlusion of the patient and drain lines can help ensure patient safety while allowing the cycler 14 to continue pumping dialysate from one or more containers 20 to the heater bag 22 or other dialysate containers 20.

[0099] In another aspect of the invention, a cassette can have patient, drain, and heater bag lines on one side or portion of the cassette and one or more dialysate supply lines on another side or portion of the cassette (e.g., on the opposite side of the cassette). Such a configuration may allow for separate occlusion of the patient, drain, or heater bag lines relative to the dialysate lines, as discussed above. Physically separating the lines attached to the cassette by type or function allows for more efficient control of interactions with lines of a certain type or function. For example, such a configuration may allow for simplified occlusion design, since less force is required to occlude one, two, or three of these lines than all lines preceding or leading away from the cassette. Alternatively, this configuration may allow for more effective automatic connection of the dialysate supply lines to the cassette, as discussed in more detail below. That is, if the dialysate supply lines and their respective connections are located away from the patient, drain, or heater bag lines, an automated uncapping and connection device can remove the caps from the spikes on the cassette, remove the caps on the dialysate supply lines, and connect the lines to their respective spikes without interference from the patient, drain, or heater bag lines.

[0100] FIG. 2 illustrates an exemplary embodiment of a cassette 24 incorporating aspects of the present invention described above. In this embodiment, the cassette 24 has a generally planar body, with the heater bag line 26, the outlet line 28, and the patient line 34 connected to respective ports on the left end of the cassette body, and the right end of the cassette body may include five spikes 160 to which the dialysate supply lines 30 may be connected. In the configuration shown in FIG. 2, each of the spikes 160 is covered by a spike cap 63, which may be removed to expose the respective spike and allow connection to the respective line 30. As described above, the lines 30 may be attached to one or more dialysate containers or other material sources, for example, for use in dialysis and / or formulation of dialysate, or may be connected to one or more collection bags for sampling purposes or a peritoneal equilibration test (PET test).

[0101] FIGS. 3 and 4 show exploded views (perspective and top views, respectively) of cassette 24 in this exemplary embodiment. Cassette 24 is formed as a relatively thin, flat member having a generally planar configuration and may include components molded, extruded, or formed from a suitable plastic, for example. In this embodiment, cassette 24 includes a base member 18 that serves as a frame or structural member for cassette 24 and defines, at least in part, the various flow channels, ports, valves, and the like. Base member 18 may be molded or constructed from a suitable plastic or other material, such as polymethyl methacrylate resin (PMMA), acrylic, or cyclic olefin copolymer / ultra-low density polyethylene (COC / ULDPE), and may be relatively rigid. In one embodiment, the COC / ULDPE ratio may be approximately 85% / 15%. Additionally, FIG. 3 shows ports for the heater bag (port 150), outlet (port 152), and patient (port 154) formed in base member 18. Each of these ports may be arranged in any suitable manner, such as on the central tube 156 or on a separate central tube extending from the outer ring or skirt 158. Flexible tubing for each of the heater bag, outlet and patient lines 26, 28, 34 may be connected to the central tube 156 and engaged by the outer ring 158 (if present).

[0102] Both sides of the base member 18 can be at least partially covered with molded, extruded, or formed membranes 15, 16 (e.g., flexible polymeric films made from polyvinyl chloride (PVC)). Alternatively, the sheet can be formed as a laminate of two or more layers of, for example, polycyclohexylene dimethylene cyclohexane dicarboxylate (PCCE) and / or low-density polyethylene (ULDPE) held together by a coextrusion adhesive resin (CXA). In some embodiments, the membrane thickness can range from about 0.002 to 0.020 inches thick. In a preferred embodiment, the PVC-based membrane thickness can range from about 0.012 to 0.016 inches thick, more preferably about 0.014 inches thick. In another preferred embodiment, such as a laminated sheet, the laminate thickness can range from about 0.006 to 0.010 inches thick, more preferably about 0.008 inches thick.

[0103] Both membranes 15 and 16 function not only to close or form part of the fluid pathways of cassette 24, but can also be operated or manipulated to open / close valve ports and / or function as part of pump diaphragms, septa, or walls that move fluid within cassette 24. For example, membranes 15 and 16 can be disposed on base member 18 and seal (e.g., by heat, adhesive, ultrasonic welding, or other means) the rim around base member 18 to prevent fluid from leaking from cassette 24. Membrane 15 can be bonded to the interior walls of base member 18, for example, forming various channels, or can be pressed into intimate contact with the walls and other features of base member 18 when cassette 24 is properly installed within cycler 14. In this manner, both membranes 15 and 16 can be positioned to seal against the peripheral rim of base member 18, helping to prevent fluid leakage from cassette 24, for example, when it is removed from cycler 14 after use, but not to contact other portions of base member 18. Once placed in cycler 14, cassette 24 can be squeezed between opposing gaskets or other members, such that membranes 15 and 16 are pressed into intimate contact with base member 18 at their inner peripheral regions, thereby properly sealing channels, valve ports, etc., from one another.

[0104] Other configurations for membranes 15 and 16 are possible. For example, membrane 16 can be formed by a rigid sheet of material bonded to or integral with body 18. As such, membrane 16 need not necessarily be or include a flexible member. Similarly, membrane 15 need not be flexible over its entire surface, but instead can include one or more flexible portions to allow pumping and / or valving, and one or more rigid portions to, for example, close fluid pathways in cassette 24. Cassette 24 could also not include membrane 16 or membrane 15, and cycler 14 could include appropriate members to seal pathways such as the cassette, control valves, and pumping functions.

[0105] According to another aspect of the present invention, the membrane 15 can include a pump chamber portion 151 (pump membrane) formed to have a shape that closely matches the shape of the recess of the corresponding pump chamber 181 in the base 18. For example, the membrane 15 can be generally formed as a flat member with a thermoformed (or otherwise formed) dome-like shape 151 that matches the pump chamber recess in the base member 18. The dome-like shape of the preformed pump chamber portion 151 can be created by heating and forming the membrane over a vacuum forming mold, for example, of the type shown in FIG. 5. As shown in FIG. 5, a vacuum can be applied through multiple holes along the mold walls. Alternatively, the mold walls can be constructed from a porous, gas-permeable material, which can result in a more uniformly smooth surface of the molded membrane. In one example, the molded membrane sheet 15 is deburred while attached to the vacuum forming mold. The vacuum forming mold then presses the deburred membrane sheet 15 against the cassette body 18, bonding them together. In one embodiment, membrane sheets 15, 16 are heat-sealed to cassette body 18. In this manner, membrane 15 can move relative to pump chamber 181 to achieve pumping action without requiring stretching of membrane 15 (or at least minimal stretching of membrane 15) both when membrane 15 is fully moved into pump chamber 181 and (potentially) into contact with spacer element 50 (e.g., as shown by the solid lines in FIG. 4 to pump fluid out of pump chamber 181) and when membrane 15 is fully retracted from pump chamber 181 (e.g., as shown by the dashed lines in FIG. 4 to draw fluid into pump chamber 181). Avoiding stretching of membrane 15 can help prevent pressure surges or other changes in fluid supply pressure due to sheet stretching and / or can help simplify pump control when attempting to minimize pressure fluctuations during pump operation. As described in more detail below, other advantages may be observed, including a reduced likelihood of failure of the membrane 15 (e.g., due to tearing of the membrane 15 caused by stresses applied to the membrane 15 during stretching) and / or improved accuracy of pump delivery measurements.In one embodiment, the pump chamber portion 151 can be formed to have a size (e.g., define a volume) that is approximately 85-110% of the pump chamber 181, and for example, if the pump chamber portion 151 defines a volume that is approximately 100% of the pump chamber volume, the pump chamber portion 151 can be located within the pump chamber 181 and rest against the spacer 50 while remaining stress-free.

[0106] Providing greater control of the pressure used to effect the fill and delivery strokes of fluid to and from the pump chamber can have several advantages. For example, it may be desirable to apply the least amount of negative pressure possible when the pump chamber draws fluid from the patient's peritoneal cavity during the delivery cycle. Patients may experience discomfort during the delivery cycle of a therapy, in part, due to the negative pressure applied by the pump during the fill stroke. The additional control that a preformed membrane can provide over the negative pressure applied during the fill stroke can help reduce patient discomfort.

[0107] Numerous other advantages can be realized by using a pump membrane preformed to the contours of the cassette pump chamber. For example, the flow rate of fluid through the pump chamber can be more uniform because a constant pressure or vacuum can be applied throughout the pumping stroke, which in turn can simplify the process of limiting fluid heating. Furthermore, temperature changes within the cassette pump may have less effect on the dynamics of the membrane's displacement and the accuracy of the measured pressure within the pump chamber. In addition, pressure spikes within the fluid line can be minimized, and it may be simpler to correlate the pressure measured by the pressure transducer on the control (e.g., pneumatic) side of the membrane with the actual pressure of the fluid on the pump chamber side of the membrane. This, in turn, can allow for more accurate head height measurements of the patient and fluid source bag prior to treatment, improve sensitivity in detecting air in the pump chamber, and improve the accuracy of volumetric measurements. Furthermore, elimination of the need for membrane stretching may allow for the construction and use of pump chambers with larger volumes.

[0108] In this embodiment, cassette 24 includes a pair of pump chambers 181 formed in base member 18 (one pump chamber or more than two pump chambers are also possible). According to an aspect of the invention, the inner walls of pump chambers 181 are spaced apart from one another and include spacer elements 50 extending from the inner walls of pump chambers 181 to help prevent portions of membrane 15 from contacting the inner walls of pump chamber 181. (As shown for right pump chamber 181 in FIG. 4 , the inner walls are defined by side 181 a and bottom 181 b. Spacer 50 extends upward from bottom 181 b in this embodiment, but could extend from side 181 a or be otherwise formed.) By preventing contact of membrane 15 with the inner walls of the pump chambers, spacer elements 50 can provide dead space (or trapped volume) that can trap air or other gas within pump chamber 181 and help inhibit gas from being pumped out of pump chamber 181 in some circumstances. In other cases, the spacer 50 can aid in the movement of gas to the outlet of the pumping chamber 181 so that gas is removed from the pumping chamber 181, for example, during priming. The spacer 50 may also help prevent the membrane 15 from adhering to the pumping chamber walls and / or allow flow to continue through the pumping chamber 181 even when the membrane 15 is forced into contact with the spacer element 50. Additionally, the spacer 50 helps prevent premature blocking of the pumping chamber outlet ports (openings 187 and / or 191) if the membrane contacts the pumping chamber walls unevenly. Further details regarding the construction and / or function of the spacer 50 are provided in U.S. Pat. Nos. 6,302,653 and 6,382,923, both of which are incorporated herein by reference.

[0109] In this embodiment, the spacer elements 50 are arranged in a sort of "stadium seating" arrangement, such that the spacer elements 50 are arranged in a concentric elliptical pattern, with the ends of the spacer elements 50 increasing in height from the bottom 181b of the inner wall the farther away from the center of the pump chamber 181, thereby forming a semi-elliptical, dome-shaped region (shown by the dashed lines in FIG. 4). Arranging the spacer elements 50 so that their ends form semi-elliptical regions that define the dome-shaped region intended to be swept by the pump chamber portion 151 of the membrane 15 may allow for a desired volume of dead space that minimizes any reduction in the intended stroke volume of the pump chamber 181. As can be seen in FIG. 3 (and FIG. 6), the "stadium seating" arrangement in which the spacer elements 50 are arranged may include "passages" or breaks 50a in the elliptical pattern. The breaks (or passages) 50a help maintain equal gas levels throughout the rows (voids or dead spaces) 50b between the spacer elements 50 as fluid is pumped from the pump chamber 181. For example, if the spacer elements 50 were arranged in the stadium seating configuration shown in FIG. 6 without the breaks (or passages) 50a or other means to allow liquid and air to flow between the spacer elements 50, the membrane 15 could bottom out on the spacer elements 50 located around the outermost perimeter of the pump chamber 181, trapping any gas or liquid present in the void between the outermost spacer elements 50 and the side 181a of the pump chamber wall. Similarly, if the membrane 15 bottoms out on any two adjacent spacer elements 50, any gas and liquid in the void between the elements 50 could become trapped. In such a configuration, at the end of the pumping stroke, air or other gases present in the center of the pump chamber 181 could be pumped out, while liquid would remain in the outer rows. Providing breaks (or passages) 50a or other means of fluid communication between the gaps between the spacer elements 50 helps maintain equal gas levels throughout the gaps during the pumping stroke, so that air or other gas can be prohibited from exiting the pump chamber 181 unless a substantial volume of liquid is being transferred.

[0110] In certain embodiments, the spacer elements 50 and / or membrane 15 can be arranged so that when the membrane 15 is pressed into contact with the spacers 50, it generally does not wrap around or deform around the individual spacers 50, or it extends significantly into the gaps between the spacers 50. Such a configuration can reduce any stretching or damage to the membrane 15 caused by wrapping around or deforming around one or more individual spacer elements 50. For example, in this embodiment, it has also been found advantageous to size the gaps between the spacers 50 so that their widths are approximately equal to the widths of the spacers 50. This feature has been shown to help prevent deformation of the membrane 15 (e.g., sagging of the membrane into the gaps between the spacers 50) when the membrane 15 is pressed into contact with the spacers 50 during pumping.

[0111] According to another aspect of the present invention, the interior wall of the pumping chamber 181 may define a recess that is larger than the space (e.g., a semi-elliptical or dome-shaped space) intended to be swept by the pumping chamber portion 151 of the membrane 15. In such an example, one or more spacer elements 50 may be positioned below the dome-shaped region intended to be swept by the membrane portion 151, rather than extending into the dome-shaped region. In certain examples, the ends of the spacer elements 50 may define the perimeter of the dome-shaped region intended to be swept by the membrane 15. Positioning the spacer elements 50 outside or adjacent to the perimeter of the dome-shaped region intended to be swept by the membrane portion 151 may have a number of advantages. For example, positioning one or more spacer elements 50 such that the spacer elements are outside or adjacent to the dome-shaped region intended to be swept by the flexible membrane minimizes any reduction in the intended stroke volume of the pumping chamber 181 while providing dead space between the spacer and the membrane, as described above.

[0112] It should be understood that the spacer elements 50 (if any) in the pump chambers can be arranged in any other suitable manner, for example, as shown in FIG. 7 . The left pump chamber 181 in FIG. 7 includes spacers 50 arranged similarly to those in FIG. 6 , but with only one break or passage 50a running vertically through approximately the center of the pump chamber 181. The spacers 50 can be arranged to define a concave shape similar to that in FIG. 6 (i.e., the top of the spacer 50 can form the semi-ellipse shown in FIGS. 3 and 4 ), or can be arranged in any other suitable manner to form a spherical, box-like shape, etc. The right pump chamber 181 in FIG. 7 illustrates an embodiment in which the spacers 50 are arranged vertically with gaps 50b, the gaps being vertically disposed between the spacers 50. In the left pump chamber, the spacers 50 in the right pump chamber 181 can define a semi-ellipse, a spherical, a box-like, or any other suitably shaped recess. However, it should be understood that the spacer elements 50 can have a fixed height, a different spatial pattern than that shown, etc.

[0113] Also, the membrane 15 itself can have spacer elements, or other features such as ribs, protrusions, tabs, grooves, channels, etc., instead of or in addition to the spacer elements 50. Such features on the membrane 15 can help prevent adhesion of the membrane 15, etc., and / or provide other features, such as helping to control how the sheet folds or deforms as it moves during pumping. For example, protrusions or other features on the membrane 15 can help the sheet deform consistently and prevent it from folding over in the same area during repeated cycles. Folding over the same area of ​​the membrane 15 over repeated cycles can cause the membrane 15 to prematurely fail in that crease area, so features on the membrane 15 can help regulate how and where the crease occurs.

[0114] In this exemplary embodiment, the base member 18 of the cassette 24 defines a plurality of controllable valve features, fluid pathways, and other structures that guide fluid movement within the cassette 24. FIG. 6 shows a plan view of the pump chamber side of the base member 18, which is also seen in the perspective view in FIG. 3. FIG. 8 shows a perspective view of the rear side of the base member 18, and FIG. 9 shows a plan view of the rear side of the base member 18. The tubing 156 for each of the ports 150, 152, and 154 is in fluid communication with a respective valve well 183 formed in the base member 18. The valve wells 183 are fluidly isolated from one another by walls surrounding each valve well 183 and by the sealing engagement of the membrane 15 with the peripheral walls of the wells 183. As described above, the membrane 15 can sealingly engage the peripheral walls of each valve well 183 (and other walls of the base member 18), for example, by being pressed into contact with the walls when mounted in the cycler 14. When the membrane 15 is not pressed into sealing engagement with the valve port 184, fluid in the valve well 183 is able to flow into the respective valve port 184. Each valve port 184 thus defines a valve (e.g., a "volcano valve") that can be opened and closed by selectively operating the portion of the membrane 15 associated with the valve port 184. As described in more detail below, the cycler 14 can selectively control the position of portions of the membrane 15 so that valve ports (such as port 184) can be opened and closed to control flow through various fluid channels and other pathways within the cassette 24. Flow through the valve ports 184 is directed to the rear side of the base member 18. For the valve ports 184 associated with the heater bag and outlet (ports 150 and 152), the valve ports 184 lead to a common channel 200 formed on the rear side of the base member 18. As in valve well 183, channel 200 is separated from other channels and paths of cassette 24 by sheet 16, which is in intimate contact with the walls of base member 18 that form channel 200.For the valve port 184 associated with the patient line port 154 , flow through the port 184 is directed to a common channel 202 on the rear side of the base member 18 .

[0115] Returning to FIG. 6 , each of the spikes 160 (shown without its cap in FIG. 6 ) is in fluid communication with a respective valve well 185, which are separated from one another by the walls and sealing engagement of the membrane 15 with the walls forming the well 185. When the membrane 15 is not in sealing engagement with the port 186, fluid in the valve well 185 can flow into the respective valve port 186 (again, the position of the portion of the membrane 15 over each valve port 186 can be controlled by the cycler 14, which opens and closes the valve port 186). Flow through the valve ports 186 is directed to the back side of the base member 18 and into the common channel 202. Thus, according to one aspect of the invention, a cassette can have multiple dialysate supply lines (or other lines supplying materials for providing dialysate) connected to a common manifold or channel of the cassette, each line having a corresponding valve for controlling flow to or from the line to the common manifold or channel. Fluid in channel 202 can enter lower openings 187 of pump chambers 181 through openings 188 that lead to lower pump valve wells 189 (see FIG. 6 ). When the respective portions of membrane 15 are not pressed into sealing engagement with ports 190, flow from lower pump valve wells 189 can pass through respective lower pump valve ports 190. As can be seen in FIG. 9 , lower pump valve ports 190 lead to channels that communicate with lower openings 187 of pump chambers 181. Flow exiting pump chambers 181 can pass through upper openings 191 and enter channels that communicate with upper valve ports 192. Flow from upper valve ports 192 (when membrane 15 is not in sealing engagement with ports 192) enters respective upper valve wells 194 and then enters openings 193 that communicate with a common channel 200 on the rear side of base member 18.

[0116] Of course, cassette 24 can be controlled so that pump chamber 181 can pump fluid to or from any of ports 150, 152, and 154 and / or any of spikes 160. For example, fresh dialysate supplied by one of containers 20 connected by line 30 to one of spikes 160 can be drawn into common channel 202 by opening the appropriate valve port 186 for the appropriate spike 160 (and possibly closing other valve ports 186 for other spikes). Also, lower pump valve port 190 can be opened and upper pump valve port 192 can be closed. The portion of the membrane 15 associated with the pump chamber 181 (i.e., the pump membrane 151) can then be moved (e.g., away from the base member 18 and the pump chamber interior wall), thereby reducing the pressure in the pump chamber 181 and thereby drawing fluid through the selected spike 160, through the corresponding valve port 186 into the common channel 202, through opening 188 into the lower pump valve well 189, through the (open) lower pump valve port 190, and through the lower opening 187 into the pump chamber 181. The valve ports 186 are independently operable, allowing fluid to be drawn through any one or combination of the spikes 160 and associated dialysate source containers 20, optionally in any desired sequence or simultaneously (of course, only one pump chamber 181 need be operable to draw fluid into itself; the other pump chambers can be rendered inoperable and remain sealed to flow by closing the appropriate lower pump valve port 190).

[0117] With fluid in pump chamber 181, lower pump valve port 190 can be closed and upper pump valve port 192 can be opened. As membrane 15 is moved toward base member 18, pressure in pump chamber 181 can increase, thereby directing fluid in pump chamber 181 through upper opening 191, through (open) upper pump valve port 192 to upper pump valve well 194, and through opening 193 to common channel 200. Fluid in channel 200 can be directed to heater bag port 150 and / or outlet port 152 (and corresponding heater bag or outlet lines) by opening the appropriate valve port 184. Thus, for example, fluid in one or more of reservoirs 20 can be drawn into cassette 24 and expelled to heater bag 22 and / or a drain.

[0118] Fluid in the heater bag 22 (e.g., after being appropriately heated on a heater tray for introduction to a patient) can be drawn into the cassette 24 by opening the valve port 184 for the heater bag port 150, closing the lower pump valve port 190, and opening the upper pump valve port 192. By moving the portion of the membrane 15 associated with the pump chamber 181 away from the base member 18, the pressure in the pump chamber 181 can be reduced, thereby allowing fluid to flow from the heater bag 22 into the pump chamber 181. With the pump chamber 181 filled with heated fluid from the heater bag 22, the upper pump valve port 192 can be closed and the lower pump valve port 190 can be opened. To deliver heated dialysate to the patient, the valve port 184 for the patient port 154 can be opened and the valve port 186 for the spike 160 can be closed. Movement of membrane 15 within pump chamber 181 toward base member 18 can increase the pressure in pump chamber 181, forcing fluid to flow through lower pump valve port 190, through opening 188 into common channel 202, and to (open) valve port 184 for patient port 154. This action can be repeated an appropriate number of times to deliver the desired volume of heated dialysate to the patient.

[0119] To drain from the patient, valve port 184 for patient port 154 can be opened, upper pump valve port 192 can be closed, and lower pump valve port 190 can be opened (spike valve port 186 can be closed). Membrane 15 can operate to draw fluid from patient port 154 into pump chamber 181. Lower pump valve port 190 can then be closed, upper valve port 192 can be opened, and valve port 184 for drain port 152 can be opened. Fluid from pump chamber 181 can then be pumped to the drain line for disposal or for drainage or sampling to a collection container (alternatively, fluid can also be sent to one or more spikes 160 / lines 30 for sampling or drainage purposes). This operation can be repeated until enough dialysate has been removed from the patient and pumped to the drain.

[0120] The heater bag 22 can also act as a mixing container. Depending on the specific treatment requirements for an individual patient, dialysate or other solutions having different compositions can be connected to the cassette 24 via the appropriate dialysate lines 30 and spikes 160. A metered amount of each dialysate is added to the heater bag 22 using the cassette 24 and mixed according to one or more predetermined compositions stored in microprocessor memory and accessible by the control system 16. Alternatively, specific treatment parameters can be input by a user via the user interface 144. The control system 16 can be programmed to calculate the appropriate mixing requirements based on the type of dialysate or dialysate container connected to the spike 160 and can then control the mixing and delivery of the defined mixture to the patient.

[0121] According to aspects of the present invention, the pressure applied by the pump to the dialysate being introduced to or removed from the patient is controlled to minimize the patient's sensation of a "tug" or "pull" caused by pressure fluctuations during the extraction and introduction operations. For example, when extracting dialysate, the suction pressure (or vacuum / negative pressure) can be reduced near the end of the extraction process, thereby minimizing the patient's sensation of dialysate removal. A similar approach can be used near the end of the introduction operation, i.e., the supply pressure (or positive pressure) can be reduced near the end of the introduction. If patients are found to be more or less sensitive to fluid movement during various cycles of therapy, different pressure profiles can be used for different introduction and / or extraction cycles. For example, a relatively higher (or lower) pressure can be used during the introduction and / or extraction cycles when the patient is asleep compared to when the patient is awake. The cycler 14 can detect the patient's sleep / wake state using, for example, an infrared motion detector and infer that the patient is asleep if their movement decreases, or use detected changes in blood pressure, brain waves, or other parameters indicative of sleep. Alternatively, the cycler 14 can simply "ask" the patient "Are you asleep?" and control system operation based on the patient's response (or lack thereof). [Patient line status detection device] In one aspect, the patient line status detector detects when a fluid line to a patient (such as patient line 34) is properly primed before connection to the patient. (Although the patient line status detector is described with respect to a patient line, it should be understood that aspects of the invention include detecting the presence of any suitable tubing segment or other conduit and / or the fill status of a tubing segment or other conduit. Thus, aspects of the invention are not limited to use with patient lines, as the tubing status detector can be used with any suitable conduit.) In some embodiments, the patient line status detector can be used to detect proper priming of a tubing segment at the patient connection end of a fluid line. The patient line 34 can be connected to a patient's indwelling catheter in a blood vessel, a body cavity, subcutaneously, or another organ. In one embodiment, the patient line 34 can be a component of a peritoneal dialysis system 10, delivering dialysate to and receiving fluid from the patient's peritoneal cavity. The tubing segment near the distal end of the line can be placed in an upright position in a cradle in which the detector's sensor element is located. FIG. 9-1A is a front perspective view of a typical configuration of patient line condition detector 1000, which can be attached to or exposed on the left exterior side of housing 82 (e.g., to the left of front door 141). Patient line 34 should preferably be primed before connection to the patient because otherwise air will be delivered to the patient, increasing the risk of complications. In some settings, it is acceptable for up to 1 mL of air to be present in patient line 34 before connection to the patient's peritoneal dialysis catheter. The typical configurations of patient line condition detector 1000 described below generally meet or exceed this criterion because they can detect a liquid level in a properly positioned tubing section of line 34, allowing at most approximately 0.2 mL of air to remain at the tip of line 34 after priming.

[0122] In one aspect, the patient line condition detector 1000 in the first configuration can include a base member 1002. A patient line condition detector housing 1006 can also be affixed to (or integrally molded with) the base member 1002, such that the detector housing 1006 extends outwardly from the base member 1002. The detector housing 1006 defines a tubing or connector-retaining channel 1012 in which the tubing section 34a near the distal end of the patient line 34 or its associated connector 36 can be disposed. The portion of the detector housing 1006 facing the base member 1002 can be substantially hollow, thereby creating an open cavity 1008 (shown in FIG. 9-3) behind the detector housing 1006. The open cavity 1008 can provide for placement and positioning of sensor elements (1026, 1028, 1030, and 1032 shown in FIG. 9-3) adjacent to the channel 1012 in which the tubing section 34a can be disposed. In other embodiments, there may optionally be a stabilizing tab 1010 extending outward from the base member 1002. The stabilizing tab 1010 may have a concave outer shape such that it substantially conforms to the curvature of the patient line connector 36 when the patient line 34 is placed in the patient line condition detector housing 1006. The stabilizing tab 1010 may help prevent the connector 36 from moving during priming of the patient line 34, thereby improving the accuracy and efficiency of the priming process. The detector housing 1006 may have a shape that generally helps define a tube or connector retention channel 1012, which may also have varying dimensions to allow for a transition from the tubing section 34a to the tubing connector 36.

[0123] In this exemplary embodiment, the channel 1012 can substantially follow the shape of the patient line connector 36. As a result, the channel 1012 can be “U-shaped” to encompass a portion of the connector 36 when it is positioned therein. The channel 1012 can be comprised of two separate features (the tubing portion 1014 and the cradle 1016). Alternatively, the tubing portion 1014 can be positioned below the cradle 1016. Additionally, the cradle 1016 can be formed by a pair of side walls 1018 and a rear wall 1020. Both side walls 1018 can be slightly convex in shape, while the rear wall 1020 can be generally horizontal or have a contour that generally matches the shape of the adjacent portion of the connector 36. The generally convex shape of the side walls 1018 helps lock the patient line connector 36 in place when positioned in the cradle 1016.

[0124] In an exemplary embodiment for the first configuration of the patient line status detector 1000, the region 36a of the patient line connector 36 can have a generally planar surface that can be fixedly positioned against an opposing rear wall 1020 of the channel 1012. Additionally, this region 36a of the connector 36 can have an opposing recess 37 that can be positioned adjacent to an opposing side wall 1018 of the channel 1012 when the connector 36 is positioned within the detector housing 1006. The recess 37 can be defined by a raised element 37a located on a side of the connector 36. One of these recesses 37 is partially visible in FIG. 9-1 . The two side walls 1018 can have a generally interlocking shape (e.g., a convex shape, etc.) that engages the recess 37 and helps lock the connector 36 in place within the cradle 1016. This helps prevent inadvertent removal of the connector 36 and tubing segment 34a from the detector housing 1006 during preparation of the patient line 34. If the raised element 37a of the connector 36 is made of a sufficiently flexible material (e.g., polypropylene, polyethylene, or other similar polymer-based material), a threshold pulling force on the connector 36 will be able to disengage the connector 36 and the tube section 34a from the detector housing 1006.

[0125] In another aspect, the tube portion 1014 of the cavity 1012 can enclose most of the tube section 34a just before the tube section 34a is attached to the connector 36. The tube portion 1014 can accommodate most of the tube section 34a using three structures: two side walls 1018 and a back wall 1020. In one embodiment, the two side walls 1018 and the back wall 1020 can be transparent or sufficiently translucent (e.g., constructed from Plexiglas) to allow light from multiple LEDs (e.g., LEDs 1028, 1030, and 1032 in FIG. 9-3) to be directed through the walls without being significantly blocked or diffused. Additionally, an optical sensor 1026 (shown in FIG. 9-2) can be positioned along one of the walls 1018 to detect light emitted by the LEDs. In an exemplary embodiment, a clear or translucent plastic insert 1019 can be constructed to snap into the main detector housing 1006 in the area where the LEDs are located within the housing.

[0126] FIG. 9-2 shows a layout perspective view with LEDs 1028, 1030, and 1032 and an optical sensor 1026 surface mounted on a patient line status detector printed circuit board 1022. FIG. 9-3 shows a top view of the LEDs 1028, 1030, and 1032 and the optical sensor 1026 mounted on a detector circuit board 1022, which can be positioned adjacent the rear wall 1020 and side wall 1018 of the detector housing 1006. FIG. 9-4 is an exploded perspective view of the detection assembly 1000, showing the relative positions of the printed circuit board 1022 and translucent or transparent plastic insert 1019 with respect to the housing 1006.

[0127] 9-1B , the detector circuit board 1022 can be disposed in the support structure 1004 and the inner open cavity 1008, which is formed from a detector housing 1006 extending outward from the base member 1002. The base member 1002 and the support structure 1004 can be attached to one another or can be integrally molded such that the base member 1002 is generally perpendicular to the support structure 1004. This orientation generally allows the plane of the detector circuit board 1022 to be generally perpendicular to the longitudinal axis of the tube section 34a when secured within the channel 1012. The detector circuit board 1022 can generally follow the cross-sectional shape of the open cavity 1008 and can also include a cutout 1024 (FIGS. 9-2 and 9-3) that generally matches the cross-sectional shape of the channel 1012 formed by the back wall 1020 and the side wall 1018 (FIG. 9-1A). The detector circuit board 1022 can then be placed into the open cavity 1008, with the cutout 1024 approximately adjacent the rear wall 1020 and side wall 1018 of the detector housing 1006 to ensure proper alignment of the detector circuit board 1022 with the tube section 34a or connector 36.

[0128] The detector circuit board 1022 may include a plurality of LEDs and at least one optical sensor that may be attached to the circuit board 1022; in one embodiment, the LEDs and optical sensor may be surface-mounted on the circuit board 1022. In one aspect, the detector circuit board 1022 may include a first LED 1028, a second LED 1030, a third LED 1032, and an optical sensor 1026. The first LED 1028 and the second LED 1030 may be positioned to direct light through the same sidewall 1018a of the channel 1012. Light emitted by the first LED 1028 and the second LED 1030 may be directed generally parallel and generally perpendicular to the sidewall 1018a to which they are closest. The optical sensor 1026 may be positioned along the opposite sidewall 1018b of the channel 1012. Additionally, the third LED 1032 may be positioned along the rear wall 1020 of the channel 1012. In this exemplary embodiment, such a configuration of the LEDs and optical sensor 1026 enables the patient line status detector 1000 to detect three different states during the priming of the patient line 34: the tubing section 34a or connector 36 is nearly completely filled with fluid (primed state), the tubing section 34a or connector 36 is incompletely filled (unprimed state), or the tubing section 34a and / or connector 36 is absent from the channel 1012 (line absent state).

[0129] When used in a peritoneal dialysis system, such as peritoneal dialysis system 10, configuring detector circuit board 1022 in this manner allows appropriate control signals to be sent to PD cycler controller system 16. Controller system 16 can then, via user interface 144, alert the user to position the distal end of line 34 in patient line status detector 1000 before connecting it to the peritoneal dialysis catheter. The controller can then monitor the positioning of tubing segment 34a within patient line status detector 1000. The controller can then direct the priming of line 34, and once line 34 is primed, direct end of priming, and then proceed to instruct the user to disengage the distal end of line 34 from patient line status detector 1000 and connect it to the user's peritoneal dialysis catheter.

[0130] Surface mounting the LEDs 1028, 1030, and 1032 and the optical sensor 1026 to the circuit board 1022 can simplify the manufacturing process of the device, can allow the patient line status detector 1000 and the circuit board 1022 to occupy a relatively small space, and can help eliminate errors that may result from movement of the LEDs or optical sensor relative to each other or relative to the channel 1012. Without surface mounting of the sensor components, misalignment of the components may occur during assembly of the device or during its use.

[0131] In one aspect, the optical axis (or central optical axis) of the LED 1032 can form an oblique angle with respect to the optical axis of the optical sensor 1026. In the illustrated embodiment, the optical axes of the first LED 1028, the second LED 1030, and the optical sensor 1026 are generally parallel to each other and to the rear wall 1020 of the channel 1012, respectively. As such, the amount of light directed from the LEDs toward the optical sensor 1026 can vary depending on (a) the presence or absence of a translucent or transparent conduit within the channel 1012 and / or (b) the presence of liquid within the conduit (which can be, for example, tube section 34a). Preferably, the LED 1032 can be positioned near the sidewall (e.g., 1018a) farthest from the optical sensor 1026 for some of the light emitted by the LED 1032 to be refracted by the presence of the translucent or transparent tube section 34a within the channel 1012. The degree of refraction away from or towards the optical sensor 1026 may depend on the presence or absence of fluid in the tube section 34a.

[0132] In various embodiments, the oblique angle of the LED 1032 relative to the optical sensor 1026 creates a more robust system for determining the presence or absence of liquid with translucent or transparent conduits in the channel 1012. The LED 1032 can be positioned so that its optical axis forms any angle between 91° and 179° with respect to the optical axis of the optical sensor 1026. Preferably, the angle can be set within a range of about 95° to about 135° with respect to the optical axis of the optical sensor. More preferably, the LED 1032 can be set to have an optical axis at about 115°±5° with respect to the optical axis of the optical sensor 1026. In the exemplary embodiment shown in FIG. 9-3 , the angle θ of the LED 1032's optical axis relative to the optical axis of the optical sensor 1026 was set to about 115°±5° (the optical axis of the optical sensor 1026 in this particular embodiment is generally parallel to the rear wall 1020 and generally perpendicular to the side wall 1018b). The benefits of angling the LED 1032 with respect to the optical axis of the optical sensor 1026 were confirmed in a series of tests comparing the performance of the optical sensor 1026 in distinguishing fluid-filled tube sections (wet tubes) from air-filled tube sections (dry tubes) using an LED 1032 oriented at an angle of approximately 115° versus an LED with its optical axis oriented perpendicular or parallel to the optical axis of the optical sensor 1026. The results showed that the angled LED-based system was more robust in identifying the presence or absence of liquid in the tube section 34a. Using the angled LED 1032, it is possible to select the optical sensor's signal intensity threshold above which an empty tube section 34a can be reliably detected. It is also possible to select the optical sensor's signal intensity threshold below which a liquid-filled tube section 34a can be reliably detected.

[0133] 9-12 show graphs of test results demonstrating the ability of the patient line status detector 1000 to identify a filled tube section 34a (the primed state) and an empty tube section 34a (the unprimed state). The results were recorded with the LED 1032 (the third LED) oriented at an angle of approximately 115° relative to the optical axis of the optical sensor 1026 and the LED 1030 (the second LED) oriented generally parallel to the optical axis of the optical sensor 1026. The results plotted in FIGS. 9-12 demonstrate that the patient line status detector 1000 can consistently distinguish between primed and unprimed states. When the relative signal strength associated with the light received from the LED 1030 was approximately 0.4 or greater, it was possible to determine the upper signal detection threshold 1027 and the lower signal detection threshold 1029 for the primed versus unprimed state using only the light signal received from the LED 1032. An upper threshold 1027 can be used to identify an unprimed state, and a lower threshold 1029 can be used to identify a primed state. Data points located above the upper threshold 1027 are associated with an empty tube segment 34a (unprimed state), and data points located below the lower threshold 1029 are associated with a tube segment 34a filled with fluid (primed state). A relatively narrow region 1031 between these two thresholds defines a range of relative signal strength associated with the light received from the LED 1032 within which assessment of the readiness of the tube segment 34a may be uncertain. A controller (e.g., control system 16) can be programmed to send an appropriate message to the user whenever the signal strength associated with the light received from the LED 1032 falls within this uncertainty range. For example, the user can be instructed to evaluate whether the tube segment 34a and / or connector 36 are properly attached to the patient line status detector 1000. In the context of a peritoneal dialysis system, if the optical sensor 1026 generates a signal corresponding to an empty tubing section 34a, the controller can instruct the cycler to continue priming the patient line 34 with dialysate.A signal corresponding to the tube section 34a being filled with fluid can be used by the controller to stop further preparations and indicate to the user that the fluid line 34 is ready to be connected to the dialysis catheter.

[0134] In one embodiment, the cycler controller can continuously monitor the signal received from one of the LEDs at the beginning of the priming process. Upon detecting a change in the received signal, the controller can stop further fluid pumping and perform sufficient measurements using all of the LEDs. If the received signal is sufficiently within a range indicative of a wet tube, further priming can be stopped. However, if the received signal is within the indeterminate region 1031 or "dry state" region, the cycler can command a series of small, increasing pulses of fluid into the patient line via the pumping cassette, with the LED signal strength repeatedly read after each pulse of fluid. Then, as soon as a reading indicative of a fluid introduction line is achieved at the level of the sensor, priming can be stopped. The increasing pulses of fluid can be achieved by commanding brief pulses of a valve connecting the pressure accumulator to the pump actuation or control chamber. Alternatively, the controller can command continuous pressure to be applied to the pump actuation or control chamber, and command the pump outlet valve to open briefly and closely to generate a series of fluid pulses.

[0135] 9-13 show graphs of test results demonstrating the superiority of an angled LED 1032 (LEDc) compared to an LED (LEDd) whose optical axis is approximately perpendicular to the optical axis of the optical sensor 1026. In this case, the relative signal strength generated by the optical sensor 1026 in response to light from LEDc was plotted against the signal strength associated with light from LEDd. Some separation between liquid-filled (primed) and empty (unprimed) tube segments 34a was evident at a relative signal strength of LEDd of approximately 0.015, but there remained a substantial number of "unprimed" data points 1035 that could not be identified from the "primed" data points based on this threshold. On the other hand, a relative signal strength 1033 associated with light from LEDc of 0.028 to 0.03 effectively identified "primed" tube segments 34a (primed state) and "unprimed" tube segments 34a (unprimed state). In this way, the angled LED (1032) can produce more reliable data than an LED oriented at a right angle.

[0136] In another embodiment, the patient line status detector 1000 can further determine whether a tubing segment 34a is present in the channel 1012. In one aspect, the first LED 1028 and the second LED 1030 can be positioned next to each other. One LED (e.g., LED 1028) can be positioned such that its optical axis passes through the approximate center of a suitably positioned translucent or transparent conduit or tubing segment 34a in the channel 1012. The second LED (e.g., LED 1030) can be positioned such that its optical axis is slightly off-center relative to the conduit or tubing segment 34a in the channel 1012. Such a centered / off-center LED pair on one side of the channel 1012 has been shown to increase the reliability of determining whether a liquid conduit or tubing segment 34a is present or absent in the channel 1012, with the optical sensor 1026 on the opposite side of the channel 1012. In a series of tests in which the tube section 34a was alternately absent, present but improperly positioned, or present and properly positioned within the channel 1012, signal measurements were taken by the optical sensor 1026 from the first LED and the second LED 1030. The signals received from each LED were plotted against each other, and the results are shown in Figures 9-14.

[0137] 9-14, in the majority of cases in which tube segment 34a was absent from channel 1012 (region 1039), the signal strength received by optical sensor 1026 due to LEDa (LEDa received strength) was found to not be significantly different from the signal strength received from LEDa during a calibration step in which LEDa was illuminated in the known absence of any tube in channel 1012. Similarly, the signal strength associated with LEDb (LEDb received strength) was found to not be significantly different from LEDb during a calibration step in which LEDb was illuminated in the known absence of any tube in channel 1012. Patient line status detector 1000 can reliably determine that no tube is present in channel 1012 when the ratio of LEDa to its calibrated value and the ratio of LEDb to its calibrated value are each approximately 1±20%. In a preferred embodiment, the threshold ratio can be set to 1±15%. In embodiments in which patient line status detector 1000 is used with a peritoneal dialysis cycler, the values ​​of LEDa and LEDb in region 1039 of FIGS. 9-14 can be used to indicate, for example, the absence of tubing segment 34a from channel 1012. The cycler controller can be programmed to pause further pumping action and alert the user via user interface 144 of the need to properly position the tip of the patient line 34 within patient line status detector 1000.

[0138] The configuration and positioning of the three LEDs and optical sensor 1026 described above allows for the necessary data to be generated using translucent or transparent fluid conduits (e.g., tubing section 34a) with a wide range of translucencies. In additional testing, it was found that the patient line status detector 1000 was able to use samples of tubing with significantly different degrees of translucency to distinguish liquid from air in the fluid conduit and provide reliable data for distinguishing the presence or absence of a fluid conduit. It was also able to provide reliable data whether the PVC tubing used was non-sterile or sterilized (e.g., sterilized with EtOx (ethylene oxide)).

[0139] Measurements obtained by the optical sensor 1026 from the LED can be used as input to the patient line status detector algorithm to detect the status of the tube segment 34a. Other than detecting a filled, empty, or absent tube segment 34a, the results of the algorithm are inconclusive and may indicate movement or improper positioning of the tube segment 34a within the patient line status detector 1000, or possibly the presence of a foreign object in the channel 1012 of the patient line status detector 1000. Manufacturing variables may change the output from the LED and the sensitivity of the optical sensor 1026 in different assemblies. Therefore, it may be advantageous to perform an initial calibration of the patient line status detector 1000. For example, the following procedure can be used to obtain calibration values ​​for the LED and sensor.

[0140] (1) Ensure that the tubing section 34a is not loaded into the patient line status detector 1000. (2) Query the optical sensor 1026 for four different states.

[0141] (a) No LEDs are lit (b) The first LED 1028 (LEDa) is lit (c) The second LED 1030 (LEDb) is lit (d) The third LED 1032 (LEDc) is lit (3) Subtract the "no LEDs lit" signal value from each of the other signal values ​​to determine their environmental correction values, and store these three measurements as the "no tube" calibration values.

[0142] Once the calibration values ​​for the LEDs and sensors are obtained, the condition of the tube section 34a can be detected. In this exemplary embodiment, the patient line condition detector algorithm performs condition detection in the test as follows:

[0143] (1) Query the optical sensor 1026 for four different states. (a) No LEDs are lit (b) The first LED 1028 (LEDa) is lit (c) The second LED 1030 (LEDb) is lit (d) The third LED 1032 (LEDc) is lit (2) Subtract the "no LEDs lit" value from each of the other values ​​to determine their environmental correction values.

[0144] (3) Calculate the relative LED values ​​by dividing the test values ​​associated with each LED by their corresponding calibrated (no tube) values. [result] If the environmentally corrected LEDa value is less than 0.10, there may be a foreign object in the detector or an indeterminate result may be reported to the user.

[0145] If the environmentally corrected LEDa and LEDb values ​​are within ±15% of their respective stored calibration (no tube) values, it reports to the user that no tube section is in the detector.

[0146] If the environmentally corrected LEDb value is approximately 40% or greater than its stored calibrated (no tube) value, (a) Check the signal associated with LEDc; (i) If the environmentally corrected signal associated with LEDc is greater than or equal to about 150% of its calibrated (no tube) value, report to the user that the tube compartment is empty.

[0147] (ii) If the environmentally corrected signal associated with LEDc is less than or equal to about 125% of its calibrated (no tube) value, report to the user that the tube compartment is filled with liquid. (iii) Otherwise, the result is inconclusive and reports to the user that the measurement should be repeated (e.g., the tube segment may be moving, uneven, or unclear) or checked to ensure that the tube segment is properly inserted into the detector.

[0148] If the environmentally corrected LEDb value is less than or equal to about 40% of its stored calibration (no tube) value, the LEDc threshold for determining the presence of a dry tube may be larger. In one embodiment, for example, the LEDc empty tube threshold has been empirically found to follow the relationship: [LEDc empty tube threshold] = -3.75 × [LEDb value] + 3.

[0149] Once it is determined that the tubing section 34a is loaded into the patient line status detector 1000, the patient line status detector algorithm may do the following: a) Query if the optical sensor 1026 has an illuminated LED and store this as the no LED value.

[0150] b) Turn on LEDc. c) Query the optical sensor 1026 and subtract the no LED value from the LEDc value and store this as the initial value.

[0151] d) Start pumping e) Query the optical sensor 1026 and subtract the no LED value from the next LEDc value.

[0152] f) If this value is less than 75% of the initial value, declare tube section 34a filled with liquid, stop pumping, check detector status using the procedure above, and report readiness to the user when indicated. Otherwise, continue to repeat the interrogation, calculation, and comparison. In one embodiment, the system controller can be programmed to perform the interrogation protocol as frequently as desired, such as every 0.005 to 0.01 seconds. In one embodiment, the entire interrogation cycle can conveniently occur every 0.5 seconds.

[0153] Figures 9-12A show the results of the sample calibration process for six cyclers. Note that the signal intensity ranges that distinguish dry tubes from wet tubes (the "wet / dry threshold" ranges) vary among the various cyclers. (These range variations can be due to slight variations in the manufacturing, assembly, and positioning of various components.) Thus, during calibration, each cycler can be assigned a wet / dry threshold signal intensity range that optimally separates data points generated by dry tubes from data points generated by wet tubes.

[0154] FIG. 9-5 shows a perspective view of a second configuration of the patient line status detector 1000. Two or more different patient line status detector configurations may be needed to accommodate various types of patient line connectors. In this exemplary embodiment, the patient line status detector 1000 of the second configuration may include most of the same components as the patient line status detector 1000 of the first configuration. However, to accommodate different types of connectors, the second configuration may include a raised element 1036 above the housing 1006 rather than the stabilizing tab 1010 found on the patient line status detector 1000 of the first configuration. The raised element 1036 may generally follow the shape of a standard patient line connector cap or connector flange.

[0155] According to an embodiment of the invention, the detector housing 1006 may not include the tubing portion 1014. Thus, the open cavity 1008 may be configured to allow for placement of the detector circuit board 1022 such that the LEDs and optical sensor are located next to the translucent or transparent patient line connector 36 rather than in a section of tubing. Thus, the channel 1012 may be shaped differently to provide for transmission of the LED light through the connector 36. [Dialysis fluid line organizer] 9-6, 9-7, and 9-8 respectively show a front perspective view of an unloaded organizer 1038, a rear perspective view of an unloaded organizer 1038, and a perspective view of a loaded organizer 1038. In this embodiment, the organizer 1038 can be substantially formed from a moderately flexible material (e.g., PAXON AL55-003 HDPE resin, etc.). Forming the organizer 1038 from this material or another relatively flexible polymeric material improves the durability of the organizer 1038 when connecting or disconnecting dialysate lines or dialysate line connectors.

[0156] The organizer 1038 can be conveniently mounted or attached to the outer wall of the cycler housing 82. The organizer 1038 can include a tube holder compartment 1040, a base 1042, and a tab 1044. The tube holder compartment 1040, the base 1042, and the tab 1044 can all be flexibly connected and substantially formed from the same HDPE-based material. The tube holder compartment 1040 can have a generally rectangular shape and can include a generally horizontal upper edge and a lower edge that can be slightly curved outward. The tube holder compartment 1040 can include a series of recessed compartments 1046 extending horizontally along the lower edge of the tube holder compartment 1040. Each of the recessed compartments 1046 can be separated by a series of support posts 1048, which can define the shape and size of the compartments 1046. The tube holder compartment 1040 may further include a raised region extending horizontally along the top edge of the tube holder compartment 1040. The raised region may include a plurality of slots 1050. The slots 1050 may be defined in a vertical orientation and may extend from the top edge of the tube holder compartment 1040 to the top of the recessed compartment 1046. The slots 1050 may have a generally cylindrical shape to mimic the shape of the outlet line 28, the dialysate line 30, or the patient line 34. The depth of the slots 1050 is such that the opening of the slot 1050 is narrower than the interior area of ​​the slot 1050. Thus, once the line is placed in the slot 1050, it is locked or snapped into place. The line may then require a predetermined minimum force to be removed from the slot 1050. This ensures that the line is not inadvertently removed from the organizer 1050.

[0157] In one aspect, the tab 1044 can be flexibly connected to the top edge of the tube holder section 1040. The tab 1044 can have a generally rectangular shape. In another embodiment, the tab 1044 can further include two slightly larger radius corners. The tab 1044 can further include two vertically extending support posts 1048. The support posts 1048 can be connected to the top edge of the tube holder section 1040 and can extend upward into the tab 1044. In alternative embodiments, the length and number of support posts 1048 can vary depending on the desired degree of flexibility of the tab 1044. In another aspect, the tab 1044 can include a ribbed region 1052. The purpose of tabs 1044 and ribbed areas 1052 is to allow a user to easily understand organizer 1038 so that the user can easily install, transport, or remove dialysate lines 30 from organizer 1038. Tabs 1044 also provide an additional support area when removing and loading the lines into organizer 1038.

[0158] In another aspect, the base 1042 can be flexibly connected to the lower edge of the tube holder section 1040. The base 1042 can have a generally rectangular shape. In another embodiment, the base 1042 can further include two slightly larger radius corners. The base 1042 can include an elongated recessed section 1046, which can be defined by a support ring 1054 that surrounds the recessed section 1046. The support posts 1050, the support ring 1054, and the raised area can all create a series of voids 1056 along the rear of the organizer 1038 (shown, for example, in FIGS. 9-7).

[0159] 9-9 and 9-10 show perspective views of an organizer clip 1058 and an organizer clip receiver 1060, respectively. In these exemplary embodiments, the clip 1058 can be made from a relatively high durometer polyurethane elastomer, such as, for example, 80 Shore A durometer urethane. In alternative embodiments, the clip 1058 can be made from any type of flexible, durable material that allows the organizer 1038 to flex and rotate along the base 1042 when placed within the clip 1058. The clip 1058 can be "U-shaped" and can have a rear portion that extends slightly higher than the front portion. Additionally, there can be a lip 1062 extending along the top edge of the front portion of the clip 1058. The lip 1062 extends slightly into the cavity of the clip 1058. The rear portion of the clip 1058 may further include a plurality of elastomeric pegs 1064 connected to (or formed from) and extending away from the rear portion of the clip 1058. The pegs 1064 may include both a cylindrical portion 1066 and a conical portion 1068. The cylindrical portion 1066 may connect to the rear portion of the clip 1058, and the conical portion 1068 may be attached to an open end of the cylindrical portion 1066. The pegs 1064 allow the clip 1058 to be permanently connected to the organizer clip receiver 1060 by engaging the pegs 1064 with a plurality of holes 1070 in the organizer clip receiver 1060.

[0160] The organizer clip receiver 1060 can include a plurality of chamfered tabs 1072. The chamfered tabs 1072 can mate with corresponding slots in the rear portion of the clip 1058 when the pegs 1064 engage the organizer clip receiver 1060. Once the chamfered tabs 1072 engage with the slots, they can extend through the rear portion of the clip 1058 and act as a locking mechanism to hold the organizer 1038 in place when placed in the clip 1058. When the organizer 1038 is placed in the clip 1058, the chamfers 1072 fit into the gaps 1056 in the rear of the base 1042 created by the raised support ring 1054. Referring again to FIGS. 9-7 and in accordance with another aspect of the present invention, a plurality of ramps 1074 can extend outward from the rear of the organizer 1038. The ramps 1074 can be generally shaped as bevels. This allows the organizer 1038 to be angled away from the cycler 14 when placed into the clip 1058, which provides numerous advantages over previous designs. For example, in this exemplary embodiment, the angle of the organizer 1038 ensures that neither the tabs 1044 nor any of the lines (or line caps) connected to the organizer 1038 interfere with the heater lid 143 when the lid 143 is opened or closed. Additionally, the angle of the organizer 1038 relative to the cycler 14, combined with the flexibility of the organizer 1038, both encourage a user to remove the dialysate lines 30 from their bottoms instead of from the connector ends 30a of the dialysate lines. Preferably, a user should not remove the dialysate lines 30 by grasping the connector ends 30a because, in doing so, the user could inadvertently remove one or more caps 31, which could result in contamination and spillage. Another benefit of the organizer 1038 is that it assists the user in connecting the color-coded dialysate lines 30 to the correct containers 20 by helping to separate the color-coded lines 30. [Door latch sensor] 9-11 show perspective views of the door latch sensor assembly 1076. In this exemplary embodiment, the door latch sensor assembly 1076 may include a magnet 1078 attached to or connected to the door latch 1080 and may pivot with the door latch 1080 as it pivots to and from a latched position with an engaged base unit catch 1082. A sensor (not shown in FIGS. 9-11) may be positioned behind the front panel 1084 of the cycler 14 near the base unit catch 1082 to detect the presence of the magnet 1078 when the door latch 1080 engages the base unit catch 1082. In one embodiment, the sensor may be an analog Hall effect sensor. The purpose of the door latch sensor assembly 1076 is to verify both that the door 141 is closed and that the door latch 1080 has fully engaged the catch 1082 to ensure a structurally sound connection. 9-11a show a cross-sectional view of the door latch sensor assembly 1076. The sensor 1079 is located on a circuit board 1077 behind the front panel 1084. The sensor 1079 is preferably oriented with an axis offset from the line of motion of the magnet 1078 because this orientation allows the sensor 1079 to better determine the various positions of the magnet 1078 as it gets closer to the front panel 1084 as the door 141 is closed.

[0161] In one example, the door 141 may be considered fully engaged when the door latch 1080 is at least 50% engaged with the catch 1082. In one embodiment, the door latch 1080 may nominally engage by approximately 0.120 inches. Additionally, the sensor 1079 may detect the closure of the door 141 only when the door latch 1080 is fully engaged with the catch 1082. Thus, the sensor 1082 may detect the closure of the door 141 only when the door latch 1080 is engaged by approximately 0.060 inches. These engagement thresholds for the door latch 1080 may be set approximately in the mid-range for acceptable engagement between the door latch 1080 and the catch 1082. This may help ensure a robust design by accounting for sensor drift due to time, temperature, and other variations.

[0162] Tests were conducted to determine the robustness of the sensor 1082 by collecting numerous measurements at both room temperature (approximately 24° C.) and unusually cold temperatures (approximately -2° C. to 9° C.). Room temperature measurements were repeatedly higher than cold temperature measurements, but by only a few percent over the range of 0 inches to 0.060 inches.

[0163] In one embodiment, the output of the sensor 1079 may have an output characteristic proportional to the voltage supplied. Therefore, both the supply voltage and the output of the sensor 1079 may be measured (see the equation below, where the supply voltage and the output of the sensor 1079 are represented by Door_Latch and Monitor_5V0, respectively). Then, both the output of the sensor 1079 and the supply voltage may be passed through a 1 / 4 resistor divider circuit. Dividing the output of the sensor 1079 and the supply voltage may allow for the generation of a stable output. This procedure may ensure that the output remains stable even as the supply voltage fluctuates.

[0164] In another embodiment, the sensor 1079 can respond to positive and negative magnetic fields. Thus, in the absence of a magnetic field, the sensor 1079 can output half the supply voltage. Additionally, a positive magnetic field can increase the output of the sensor 1079, while a negative magnetic field can decrease the output of the sensor 1079. To obtain an accurate measurement of the output from the sensor 1079, the polarity of the magnet can be ignored and the supply voltage can be compensated for at the same time. The following equation can be used to calculate the latch-sensor ratio:

[0165] Latch-sensor ratio = absolute value (VDoor_Latch / VMonitor_5V0) - noFieldRatio) … (1) The noFieldRatio (no shim ratio) is calculated by (VDoor_Latch / VMonitor_5V0) when the door 141 is fully open.

[0166] Using this formula, A ratio of 0.0 indicates no magnetic field, A ratio >0.0 indicates some magnetic field, but does not specify a direction.

[0167] To calibrate the magnetic field strength detected by the sensor 1079 with various positions of engagement of the door latch assembly 1076, shims of various thicknesses can be used between the inside of the door 141 and the front panel 1084, thereby changing the degree of engagement between the latch 1080 and the catch 1082. In one embodiment, this data can be used to determine the magnetic field strength ratio with and without the shim, and in other embodiments, several shims of various thicknesses can be used. In one example, the door latch sensor assembly 1076 can complete a procedure to determine whether the door latch 1080 is fully engaged with the catch 1082 by doing the following:

[0168] Calculate the nearRatio and farRatio. nearRatio=noShimRatio-(0.025 / 0.060)×(noShimRatio-withShimRatio) …(2) farRatio=noShimRatio-(0.035 / 0.060)×(noShimRatio-withShimRatio) …(3) In one embodiment, the door latch sensor assembly 1076 may save the noFieldRatio, nearRatio, and farRatio in a calibration file. The door latch sensor assembly 1076 may then load the noFieldRatio, nearRatio, and farRatio from the calibration file, and the sensor assembly 1076 may then use the nearRatio and farRatio as the hysteresis range for the sensor 1079. The door latch sensor assembly 1076 may then start from an initial condition of the door 141 being open and then iteratively calculate the latch sensor ratio. If the latch sensor ratio is greater than or equal to the nearRatio, the door latch sensor assembly 1076 changes the latch state to closed, and if the latch sensor ratio is less than or equal to the farRatio, the door latch sensor assembly 1076 changes the latch state to open. In another embodiment for the door latch sensor assembly 1076, the middleRatio can be calculated from the calibration data by taking the average of the noShimRatio and the withShimRatio, where a measurement above the middleRatio indicates that the door latch 1080 is engaged and a measurement below the middleRatio indicates that the door latch 1080 is not engaged. [Settings loading and operation] FIG. 10 shows a perspective view of the APD system 10 of FIG. 1 with the door 141 of the cycler 14 lowered to an open position, exposing a mounting location 145 for the cassette 24 and a carriage 146 for the dialysate line 30. (In this embodiment, the door 141 is attached to the cycler housing 82 by a hinge at the bottom of the door 141.) When loading the set 12, the cassette 24 is placed in the mounting location 145 with the membrane 15 and the pump chamber side of the cassette 24 facing upward, and the portions of the membrane 15 associated with the pump chamber and valve ports interact with a control surface 148 of the cycler 14 when the door 141 is closed. The mounting location 145 can be shaped to match the shape of the base member 18, thereby ensuring proper orientation of the cassette 24 in the mounting location 145. In this exemplary embodiment, cassette 24 and mounting location 145 have a generally rectangular shape with a single large radius corner to require the user to properly orient cassette 24 in mounting location 145 or prevent door 141 from closing. However, it should be understood that other shape or orientation features for cassette 24 and / or mounting location 145 are possible.

[0169] According to an aspect of the present invention, when cassette 24 is placed in mounting position 145, patient, outlet, and heater bag lines 34, 28, and 26 are routed leftward through channel 40 in door 141, as shown in FIG. 10. Channel 40, which may include guides 41 or other features, may hold patient, outlet, and heater bag lines 34, 28, and 26 such that occlusion 147 selectively opens and closes the lines for flow. Upon closing door 141, occlusion 147 may press one or more of patient, outlet, and heater bag lines 34, 28, and 26 against occlusion stopper 29. Generally, occlusion 147 may allow flow through lines 34, 28, and 26 when cycler 14 is operational (and operating properly), but occludes the lines (which may be accomplished by compressing or pinching the lines to close the fluid path therethrough) when cycler 14 is powered down (and / or not operating properly). Preferably, occlusion 147 may selectively occlude at least patient and drain lines 34 and 28.

[0170] When cassette 24 is mounted and door 141 is closed, the pump chamber side of cassette 24 and membrane 15 can be forced into contact with control surface 148, for example, by an air bladder, spring, or other suitable configuration of door 141 behind mounting location 145 that compresses cassette 24 between mounting location 145 and control surface 148. This containment of cassette 24 can force membranes 15 and 16 into contact with walls and other features of base member 18, thereby isolating channels and other fluid paths of cassette 24 as desired. Control surface 148 can include a flexible gasket (e.g., a sheet of silicone rubber or other material) associated with membrane 15 that can selectively move portions of membrane 15 to effect pumping of pump chamber 181 and opening and closing valve ports of cassette 24. Control surface 148 can be associated with various portions of membrane 15, e.g., can be intimately attached to one another, such that portions of membrane 15 move in response to actuation of corresponding portions of control surface 148. For example, membrane 15 and control surface 148 can be positioned in close proximity to one another, and a suitable vacuum (or subambient pressure) can be introduced and maintained between membrane 15 and control surface 148 through appropriately positioned vacuum ports in control surface 148, such that membrane 15 and control surface 148 essentially adhere to one another, at least in areas of membrane 15 requiring actuation to open or close valve ports and / or provide pumping action. In another embodiment, membrane 15 and control surface 148 can be attached to or appropriately associated with one another.

[0171] In some embodiments, the control surface 148 or gasket surface facing the corresponding cassette membrane overlying the pump chambers and / or valves is textured or roughened. The texturing creates multiple small passages, either horizontally or tangentially, along the gasket surface as the gasket is pulled against the corresponding cassette membrane surface. This can improve air evacuation between the gasket surface and the cassette membrane surface in a textured configuration. It can also improve the accuracy of pump chamber volume determination using a pressure-volume relationship (e.g., as in the FMS process described elsewhere) by minimizing trapped air pockets between the gasket and membrane. It can also improve detection of any liquid that may leak into the potential space between the gasket and cassette membrane. In certain embodiments, texturing can be achieved by masking portions of the gasket mold that do not form part of the gasket corresponding to the locations of the pump and valve membranes. An etching process, such as the Mold-Tech® texturing and etching process, can then be applied to the unmasked portions of the gasket mold. Texturing can be achieved using electrical discharge machining, or by any of a number of other processes such as sand blasting, laser etching, or by utilizing mold making processes.

[0172] Prior to closing the door 141 with the cassette 24 loaded, one or more dialysate lines 30 may be loaded onto the carriage 146. The end of each dialysate line 30 may include a cap 31 and an area 33 for labeling or attaching an indicator or identifier. For example, the indicator may be a specific tag that snaps onto the tubing at the indicator area 33. According to aspects of the invention, and as discussed in more detail below, the carriage 146 and other components of the cycler 14 may be manipulated to remove the caps 31 from the lines 30, recognize the indicator for each line 30 (which may provide an indication as to the type of dialysate, amount of dialysate, etc., associated with the line), and fluidly engage the lines 30 with respective spikes 160 of the cassette 24. This process can be automated (e.g., after the door 141 is closed, the cap 31 and spike 160 are enclosed in a space protected from human contact, thereby potentially reducing the risk of contamination of the line 30 and / or spike 160 when connecting the two together). For example, upon closure of the door 141, the indicator area 33 may be evaluated (e.g., visually with appropriate imaging equipment and software-based image recognition, by RFID technology, etc.) to identify what dialysate is associated with which line 30. The ability to detect characteristics of the line 30 by the indicator in the indicator area 33 This aspect of the invention can provide advantages such as allowing a user to place lines 30 anywhere on carriage 146 without affecting system operation. That is, because cycler 14 can automatically detect the characteristics of the dialysate lines, it is not necessary to ensure that a particular line is placed in a particular location on carriage 146 for the system to function properly. Instead, cycler 14 identifies which lines 30 are where and appropriately controls cassette 24 and other system features. For example, one line 30 and connected container may be intended to receive spent dialysate, e.g., for later testing.Because the cycler 14 can identify the presence of the sample supply line 30, the cycler 14 can route spent dialysate to the appropriate spike 160 and line 30. As discussed above, because the spikes 160 of a cassette 24 all feed a common channel, the input from any particular spike 160 can be routed to the cassette 24 in any desired manner by controlling the valves and other cassette features.

[0173] With the line 30 attached, the carriage 146 can be moved leftward as shown in FIG. 10 (again, with the door 141 closed) to place a cap 31 on each spike cap 63 on the spikes 160 of the cassette 24 and adjacent to the cap stripper 149. The cap stripper 149 can extend outward (from inside a recess in the housing of the cycler 14 toward the door 141) to engage the cap 31 (e.g., the cap stripper 149 can include five fork-shaped elements that engage corresponding grooves in the cap 31, thereby allowing the cap stripper 149 to resist side-to-side movement of the cap 31 relative to the cap stripper 149). Engaging the cap 31 with the cap stripper 149 also allows the cap 31 to grip the corresponding spike cap 63. Thereafter, with the caps 31 engaged with the corresponding spike caps 63, the carriage 146 and cap stripper 149 can move to the right, thereby removing the spike caps 63 from the spikes 160 that engage the corresponding caps 31. (One possible advantage of this configuration is that the spike caps 63 are not removed in positions where the dialysate line 30 is not installed, because engagement of the caps 31 from the dialysate line 30 is required to remove the spike caps 63. Thus, when a dialysate line is not connected to the spikes 160, the caps on the spikes 160 remain in place.) The cap stripper 149 can then stop its movement to the right (e.g., by contacting a stopper) while the carriage 146 continues its movement to the right. As a result, the carriage 146 can pull the terminal ends of the lines 30, which remain attached to the cap stripper 149, from the caps 31.With the cap 31 removed from the line 30 (and the spike cap 63 still attached to the cap 31), the cap stripper 149 can again retract with the cap 31 into the recess in the housing of the cycler 14, thereby clearing the path of travel of the carriage 146 and the uncapped end of the line 30 toward the spike 160. The carriage 146 then again moves leftward and attaches the terminal end of the line 30 to the respective spike 160 of the cassette 24. This connection can be made by the spike 160 piercing the end of the line 30 (which would otherwise be closed), allowing fluid flow from the respective container 20 to the cassette 24 (e.g., the spike can pierce the closed septum or wall of the terminal end). In one embodiment, the wall or septum can be constructed from a flexible and / or self-sealing material, such as PVC, polypropylene, or silicone rubber.

[0174] According to aspects of the invention, heater bag 22 can be placed in heater bag receptacle (e.g., tray) 142, which is exposed by lifting lid 143. (In this embodiment, as discussed below, cycler 14 includes a user or operator interface 144 pivotally mounted to housing 82. Interface 144 can be pivoted upwardly out of tray 142 to allow heater bag 22 to be placed in tray 142.) As is known in the art, heater tray 142 can heat the dialysate in heater bag 22 to an appropriate temperature (e.g., a temperature appropriate for introduction into a patient). According to aspects of the invention, lid 143 can be closed, for example, after placing heater bag 22 in tray 142, thereby helping to trap heat and facilitate the heating process and / or helping to prevent touching or other contact with relatively warm portions of heater tray 142, such as its heated surface. In one embodiment, the lid 143 can be locked in a closed position, thereby preventing contact with heated portions of the tray 142, for example, in situations where portions of the tray 142 heat up to temperatures that could result in skin burns. Opening of the lid 143 can be prevented, for example by the lock, until the temperature under the lid 143 is at an appropriately low temperature.

[0175] According to another aspect of the present invention, the cycler 14 includes a user or operator interface 144 that is pivotally mounted to the housing of the cycler 14 and can be folded down onto the heater tray 142. With the interface 144 folded down, a lid 143 can be closed, thereby hiding and / or preventing contact with the interface 144. The interface 144 can be configured to display information to a user, for example, in graphical form, and to accept input from the user, for example, using a touchscreen and GUI. The interface 144 can include other input devices, such as buttons, dials, knobs, pointing devices, etc. With the set 12 connected and the container 20 properly positioned, the user can interact with the interface 144 to cause the cycler 14 to initiate a procedure and / or perform other functions.

[0176] However, before a dialysis cycle can begin, unless the set 12 is provided in a pre-primed state (e.g., at a manufacturing facility or prior to use in the cycler 14), the cycler 14 must at least prime the cassette 24, patient line 34, heater bag 22, etc. Primement can be accomplished in a variety of ways, such as by controlling the cassette 24 (i.e., pumps and valves) to draw fluid from one or more dialysate containers 20 via line 30 and pump the fluid through various channels in the cassette 24, thereby removing air from the cassette 24. Dialysate can be pumped into the heater bag 22 (e.g., for heating prior to delivery to the patient). Once the cassette 24 and heater bag line 26 are primed, the cycler 14 can then prime the patient line 34. In one embodiment, the patient lines 34 can be primed by connecting the lines 34 to the appropriate port or other connection on the cycler 14 (e.g., via connector 36) and causing the cassette 24 to pump fluid into the patient lines 34. The port or connection on the cycler 14 can be configured to detect the arrival of fluid at the end of the patient line (e.g., optically, via a conductivity sensor, or otherwise) to thereby detect that the patient line has been primed. As discussed above, various types of sets 12 can have different sized patient lines 34 (e.g., adult or pediatric size). According to aspects of the invention, the cycler 14 can detect the type of cassette 24 (or at least the type of patient line 34) and control the cycler 14 and cassette 24 accordingly. For example, the cycler 14 can determine the volume of fluid delivered by the pump in the cassette needed to prime the patient line 34 and determine the size of the patient line 34 based on this volume. Other techniques may also be used, such as recognizing a bar code or other indicator on the cassette 24, patient line 34, or other component that indicates the type of patient line.

[0177] FIG. 11 shows a perspective view of the inside of the door 141 disconnected from the housing 82 of the cycler 14. This view more clearly shows how the line 30 is received within corresponding grooves in the door 141 and carriage 146, such that the indicator area 33 is captured in a specific slot in the carriage 146. With the indicator in the indicator area 33 properly positioned when the tubing is attached to the carriage 146, a reader or other device can identify the indicator markings (e.g., representing the type of dialysate in the container 20 connected to the line 30, the amount of dialysate, the date of manufacture, the manufacturer's identity, etc.). The carriage 146 is attached to a pair of guides 130 at the upper and lower ends of the carriage 146 (only the lower guide 130 is shown in FIG. 11 ). In this manner, the carriage 146 can move from left to right on the door 141 along the guides 130. When moving toward the cassette mounting position 145 (to the right in FIG. 11), the carriage 146 can move until it comes into contact with the stopper 131.

[0178] 11-1 and 11-2 show perspective views of the carriage 146 and an enlarged perspective view of the dialysate line 30 mounted on the carriage 146. In these exemplary embodiments, the carriage 146 may be capable of moving on the door 141 along the guide 130. The carriage 146 may include five slots 1086 and thus may be capable of supporting up to five dialysate lines 30. Each slot 1086 may include three distinct portions: a dialysate line portion 1088, an ID portion 1090, and a clip portion 1092. The dialysate line portion 1088 may have a generally cylindrical cavity that allows the dialysate line 30 to remain organized and untangled when mounted on the carriage 146. The clip portions 1092 may be located at opposite ends of the slots 1086 relative to the dialysate line portions 1088. The purpose of clip portion 1092 is to provide a secure housing for membrane port 1094 located at connector end 30a of dialysate line 30, preventing the dialysate line 30 from moving during treatment.

[0179] In one embodiment of the present invention, the clip portion 1092 may have a semicircular shape and may include a middle region that extends slightly deeper than the two peripheral edge regions. The purpose of the deeper middle region is to accommodate the membrane port flange 1096. The flange 1096 may have a radius that is substantially larger than the remainder of the membrane port. Thus, the deeper middle region is designed to fit over the wider flange 1096, and the two edge regions provide support to prevent movement of the membrane port 1094. Additionally, the deep middle region may have two cutouts 1098 located on opposite sides of the semicircle. The cutouts 1098 may have a generally rectangular shape, allowing a small portion of the flange 1096 to extend into each of the cutouts 1098 when placed on the clip portion 1092. The cutouts 1098 may be formed such that the distance between the upper edges of each cutout 1098 is slightly less than the radius of the flange 1096. Therefore, a sufficient amount of force is required to snap the flange 1096 onto the clip portion 1092. Also, allowing the distance between the upper edges of the two cutouts 1098 to be less than the radius of the flange 1096 helps prevent the dialysate line 30 from being inadvertently removed during treatment.

[0180] In this exemplary embodiment, the carriage 146 can provide superior performance over previous designs due to its ability to resist any deformation of the membrane port 1094. The carriage 146 is designed to extend the membrane port 1094 between the front of the flange 1096 and the rear of the sleeve. The walls of the carriage 146 can support the flange 1096 if the membrane port 1094 is extended further at any point during the procedure.

[0181] According to another aspect of the present invention, ID portion 1090 can be disposed between dialysate line portion 1088 and clip portion 1092. ID portion 1090 can have a generally rectangular shape and thus can accommodate an identification tag 1100 that can be snapped onto dialysate line 30 at indicator area 33. Indicator area 33 can have an annular shape sized and configured to fit within ID portion 1090 when attached to carriage 146. Identification tag 1100 can provide an indication of the type of dialysate associated with each line 30, the amount of dialysate, the date of manufacture, and the manufacturer's identity. As shown in FIG. 11-1 , ID portion 1090 can include a two-dimensional (2-D) barcode 1102 that can be printed on the bottom of ID portion 1090. Barcode 1102 can be a data matrix symbol with 10 blocks per side and can include an "empty" data matrix code. The bar code 1102 can be placed on the carriage 146 directly below the identification tag 1100 when the dialysate line 30 is loaded onto the carriage 146. However, in an alternative embodiment, the bar code 1102 can be applied to the ID portion 1090 of the carriage 146 by a sticker or laser engraving. Also, in another embodiment, the bar code 1102 can include a data matrix with varying length and width dimensions and a varying number of blocks per side.

[0182] However, in this exemplary embodiment, the particular number of blocks per side and the particular length and width of each barcode 1102 were specifically selected to provide the most robust design under a variety of conditions. Using only 10 blocks per side would result in a barcode 1102 with larger blocks, which would therefore ensure that the barcode 1102 is easily readable even in the dark conditions present inside the cycler housing 82.

[0183] 11-3 and 11-4 show perspective views of a folded identification tag 1100 and a carriage drive assembly 132 with an Auto ID camera 1104 mounted on an Auto ID camera board 1106, respectively. According to an embodiment of the present invention, the identification tag 1100 can be formed from an injection mold, which can then be folded to snap near the indicator area 33. The identification tag 1100 can have rolled edges, which can prevent damage to the dialysate container 20 during transport. The identification tag 1100 can further include an 8x8 mm two-dimensional (2-D) data matrix symbol 1103 with 18 blocks per side and a quiet band (which can be provided by a sticker). Information contained in these data matrix symbols 1103 can be provided from the camera 1104 to the control system 16, which can then obtain indicia through various processes, such as image analysis. Thus, the Auto ID camera 1104 will have the ability to detect slots 1086 containing correctly placed dialysate lines 30, incorrectly placed lines 30, or missing lines 30. A correctly placed dialysate line 30 allows the camera 1104 to detect the data matrix symbol 1103 located on the specific tag 1100, an absence of a dialysate line 30 allows the camera 1104 to detect the "empty" data matrix barcode 1102 located on the carriage 146 directly below the membrane port 1094, and an incorrectly loaded dialysate line 30 will occlude the "empty" data matrix barcode 1102, resulting in no data matrix being encoded by the camera 1104 for that slot. Thus, the camera 1104 should always encode the data matrix in all slots 1086 on the carriage 146, revealing an incorrectly loaded dialysate line 30.

[0184] In this exemplary embodiment, the ability to detect the characteristics of the dialysate lines 30 by the specific tags 1100 located in the indicator areas 33 can provide advantages such as allowing the user to place the lines 30 anywhere on the carriage 146 without impacting system operation. Additionally, because the cycler 14 can automatically detect the characteristics of the dialysate lines, it is not necessary to ensure that a particular line 30 is placed in a specific location on the carriage 146 for the system to function properly. Instead, the cycler 14 can identify which lines 30 are where and appropriately control the cassette 24 and other system features.

[0185] According to another aspect of the present invention, the special tag 1100 must face the carriage drive assembly 132 to be encoded by the camera 1104. To ensure this, the carriage 146 and the special tag 1100 may have complementary positioning features. Furthermore, the dialysate line 30 with the special tag 1100 should also be compatible with clean-flush dialysis machines; therefore, the dialysate line 30 with the special tag 1100 may be constructed to fit within a 0.53-inch diameter cylinder. In one embodiment, the positioning feature may be a simple flat-bottom bill on the special tag 1100 and a matching rib on the carriage 146. In one embodiment of the present invention, the bill and rib may interfere slightly, pushing the rear of the special tag 1100 upward. This arrangement may cause a small amount of misalignment, but reduces misalignment in another axis. Finally, to ensure that the particular tag 1100 is properly installed, the front of the carriage drive assembly 132 can be designed with only about 0.02 inches of clearance relative to the current positioning of the carriage 146 and the particular tag 1100.

[0186] According to another aspect of the present invention, an Auto ID camera board 1106 can be mounted to the rear of the carriage drive assembly 132. In addition, an Auto ID camera 1104 can be mounted to the camera board 1106. The camera board 1106 can be positioned approximately 4.19 inches from the specific tag 1100. However, in other embodiments, the camera board 1106 can be moved rearward without any significant consequences. A plastic window 1108 can also be mounted to the front of the carriage drive assembly 132, which allows the specific tag 1100 to be imaged while also preventing fluid and finger ingress. The Auto ID camera 1104 can include a camera lens, which can be any type of lens used in security applications or a lens intended for a camera phone with the IR filter removed. According to an aspect of the present invention, the camera lens can be small, lightweight, low-cost, and have high image quality.

[0187] Additionally, a single SMD infrared LED 1110 can be mounted on the camera board 1106. The LED 1110 can then illuminate the specific tag 1100 so that the camera 1104 can easily encode the data matrix. Illumination of the specific tag 1100 is important because the interior environment of the cycler housing 82 is nearly light-free. Therefore, without the LED 1110 illuminating the specific tag 1100, the camera 1104 would not be able to encode the data matrix. Furthermore, to avoid generating a flash in front of the specific tag 1100, the LED 1110 can be mounted 0.75 inches away from the camera 1104. An FPGA can also be mounted on the camera board 1106 and act as a relay between the OV3640 image sensor and the Voyager's UI processor. In addition to making the processor's job easier, this architecture can allow for the use of different image sensors without any changes to any other Voyager hardware or software. Finally, image coding is handled by the open-source package libdmtx, which is addressable from numerous programming languages ​​and can be run from the command line for testing.

[0188] FIG. 12 shows a perspective view of the carriage drive assembly 132 in the first embodiment, which functions to move the carriage 146 to remove caps from spikes 160 on the cassette, remove caps 31 on the dialysate lines 30, and connect the lines 30 to the spikes 160. The drive element 133 is configured to move from left to right along a rod 134. In this exemplary embodiment, an air bladder powers the movement of the drive element 133 along the rod 134, although any suitable drive mechanism can be used, including a motor, hydraulics, etc. The drive element 133 has a forwardly extending tab 135 that engages with a corresponding slot 146a on the carriage 146 (see FIG. 11, which shows the upper slot 146a on the carriage 146). Engagement of the tab 135 with the slot 146a allows the drive element 133 to move the carriage 146 along the guide 130. The drive element 133 further includes a window 136 through which an imaging device, such as a CCD or CMOS imager, can capture image information of the indicators in the indicator area 33 on the line 30 mounted on the carriage 146. Image information regarding the indicators in the indicator area 33 can be provided to the control system 16, which can obtain indicia from the imaging device, for example, by image analysis. The drive element 133 can selectively move the cap stripper 149 both left and right along the rod 134. The cap stripper 149 extends back and forth using a separate drive mechanism, such as a pneumatic bladder.

[0189] FIG. 13 shows a left perspective view of the carriage drive assembly 132, which more clearly illustrates how the stripper elements of the cap stripper 149 are positioned to slide in and out along grooves 149a in the housing of the cap stripper 149 (in a direction generally perpendicular to the rod 134). Each semicircular cutout of the stripper element extends forward to engage a corresponding groove in the cap 31 on the line 30 when the cap 31 is properly positioned in front of the stripper 149 by the drive element 133 and carriage 146. With the stripper elements engaged with the cap 31, the cap stripper 149 can move with the carriage 146 as the drive element 133 moves. FIG. 14 shows a partial rear view of the carriage drive assembly 132. In this embodiment, the drive element 133 is moved toward the mounting location 145 of the cassette 24 by a first bladder 137, which expands to move the drive element 133 to the right in FIG. 14 . The drive element can be moved to the left by a second bladder 138. Alternatively, the drive element 133 can be moved back and forth by one or more motors coupled to a linear drive gear assembly, such as a ball screw assembly (with the carriage drive assembly attached to a ball nut) or a rack and pinion assembly. The stripper element 1491 of the cap stripper 149 can be moved in and out of the cap stripper housing by a third bladder, or alternatively, by a motor coupled to a linear drive assembly, as previously described.

[0190] 15-18 show another embodiment of the carriage drive assembly 132 and cap stripper 149. As can be seen in the rear view of the carriage drive assembly 132 in FIG. 15, in this embodiment, the drive element 133 is moved side to side by a screw drive mechanism 1321. As can be seen in the right rear perspective view of the carriage drive assembly 132 in FIG. 16, the stripper element is moved outward and inward by an air bladder 139, although other configurations are possible as discussed above.

[0191] 17 and 18 show left and right front perspective views of another embodiment of the stripper element 1491 of the cap stripper 149. In the embodiment shown in FIG. 13, the stripper element 1491 included only a fork-shaped element configured to engage the cap 31 of the dialysate line 30. In the embodiment of FIGS. 17 and 18, the stripper element 1491 includes not only the fork-shaped element 60 but also rocker arms 61 pivotally attached to the stripper element 1491. As will be described in more detail below, the rocker arms 61 support the removal of the spike caps 63 from the cassette 24. Each of the rocker arms 61 includes a dialysate line cap engaging portion 61 a and a spike cap engaging portion 61 b. The rocker arm 61 is normally biased to operate, so that the spike cap engaging portion 61b is positioned near the stripper element 1491, as shown for the rocker arm 61 in Fig. 18. However, when the cap 31 is received by the corresponding fork-shaped element 60, the dialysate line cap engaging portion 61a contacts the cap 31, which pivots the rocker arm 61, so that the spike cap engaging portion 61b moves away from the stripper element 1491, as shown in Fig. 17. This position allows the spike cap engaging portion 61b to contact the spike cap 63 (particularly the flange on the spike cap 63).

[0192] FIG. 19 shows a front view of the stripper element 1491 and the location of several cross-sections shown in FIGS. 20-22. FIG. 20 shows the rocker arm 61 without the spike cap 63 or dialysate line cap 31 positioned adjacent to the stripper element 1491. The rocker arm 61 is pivotally attached to the stripper element 1491 at a location approximately midway between the spike cap engaging portion 61b and the dialysate cap engaging portion 61a. As noted above, the rocker arm 61 is normally biased to rotate counterclockwise as shown in FIG. 20, so that the spike cap engaging portion 61b is positioned adjacent to the stripper element 1491. 21 shows that the rocker arm 61 maintains this position (i.e., the spike cap engaging portion 61b is in proximity to the stripper element 1491) even when the stripper element 1491 advances toward the spike cap 63 without a dialysate line cap 31 engaging the fork-shaped element 60. As a result, the rocker arm 61 does not rotate clockwise or engage with the spike cap 63 unless a dialysate line cap 31 is present. In this manner, the spike cap 63 that does not engage with the dialysate line cap 31 is not removed from the cassette 24.

[0193] 22 illustrates an example in which the dialysate line cap 31 engages the fork-shaped element 60 and contacts the dialysate line cap engaging portion 61a of the rocker arm 61. This rotates the rocker arm 61 in a clockwise direction (as shown in the figure), causing the spike cap engaging portion 61b to engage the spike cap 63. In this embodiment, the engagement of portion 61b includes positioning portion 61b adjacent to the second flange 63a on the spike cap 63, such that when the stripper element 1491 is moved to the right (as shown in FIG. 22), the spike cap engaging portion 61b contacts the second flange 63a and assists in pulling the spike cap 63 from the corresponding spike 160. Note that the dialysate line cap 31 is made of a flexible material, such as silicone rubber, which allows the barb 63c of the spike cap 63 to expand the hole 31b of the cap 31 (see FIG. 23) and be captured by a peripheral internal groove or recess in the cap 31. A first flange 63b on the spike cap 63 acts as a stopper for the end of the dialysate line cap 31. The walls defining the groove or recess in the hole 31b of the cap 31 can be symmetrical or, preferably, asymmetrically configured to follow the shape of the barb 63c (see FIG. 33 for a cross-sectional view of the cap 31 and groove or recess). A second flange 63a on the spike cap 63 acts as a tooth that the spike cap engaging portion 61b of the rocker arm 61 engages to provide additional pulling force, if necessary, to disengage the spike cap 63 from the spike 160.

[0194] FIGS. 11-5 and 11-6 show two different perspective views of another embodiment of the stripper element 1491 of the cap stripper 149. The stripper element 1491 in the embodiment shown in FIG. 13 uses a fork-shaped element 60 configured to engage the cap 31 of the dialysate line 30. In the embodiment shown in FIG. 11-5, the stripper element 1491 not only includes the fork-shaped element 60, but can also include a plurality of sensing elements 1112 and a plurality of rocker arms 1114. The sensing elements 1112 and rocker arms 1114 can be arranged in two parallel rows running vertically along the stripper element 1491. In one embodiment, each column can include five individual sensing elements 1112 and rocker arms 1114, each generally aligned with a corresponding row of the fork-shaped elements 60. Each sensing element 1112 can be mechanically connected or linked to one of the corresponding rocker arms 1114. Additionally, the assembly including each sensing element 1112 and rocker arm 1114 can include a biasing spring (not shown) that continues to bias each rocker arm 1114 toward a disengaged position, with the sensing element 1112 in a position where it is contacted and moved by the presence of a dialysate line cap 31 on the fork-shaped element 60. Each sensing element 1112 can be displaced and tilted toward the rear of the stripper element 1491 by contact with the corresponding dialysate line cap 31 on the fork-shaped element 60. Through the mechanical connection between the sensing element 1112 and the rocker arm 1114, the rocker arm 1114 can pivot or tilt laterally toward the spike cap 63 upon contact between the dialysate line cap 31 and the sensing element 1112. As the rocker arm 1114 rotates or tilts toward the spike cap 63, it can engage the second flange 63a on the spike cap 63, allowing the stripper assembly to remove the spike cap 63 from its corresponding spike.

[0195] 11-7a-11-7c illustrate the relationship between the sensing element 1112 and the dialysate line cap 31 and between the rocker arm 1114 and the spike cap 63. FIG. 11-7c shows the sensing element 1112 and the rocker arm 1114 without the spike cap 63 and the dialysate line cap 31. As shown in FIG. 11-7b, the outer flange 31c of the dialysate line cap 31 has a diameter large enough to contact the sensing element 1112. As shown in FIG. 11-7a, without the dialysate line cap 31, the spike cap 63 alone does not contact the sensing element 1112 sufficiently to displace and rotate it away from the spike cap 63. As shown in FIG. 11-7b, displacement of the detection element 1112 rotates or tilts the rocker arm 1114 toward the spike cap 63, eventually rotating or tilting it to a point adjacent to the flange 63a of the spike cap 63. As shown in FIG. 11-7a, when the rocker arm 1114 is in the non-deployed position, it can clear a predetermined amount (e.g., 0.040 inches) of the outer periphery of the second flange 63a of the spike cap 63. Upon movement of the rocker arm 1114 to the deployed position, its range of movement can be configured to apply a slight compressive force against its corresponding spike cap 63 to ensure secure engagement.

[0196] Once the rocker arm 1114 is positioned adjacent to the flange 63a of the spike cap 63, movement of the stripper element 1491 to the right engages the spike cap 63 via the flange 63a and assists in pulling the spike cap 63 from its corresponding spike 160. In the absence of a dialysate line and its associated dialysate line cap 31, the stripper element 1491 does not remove the corresponding spike cap 63, leaving its associated spike 160 sealed. In this manner, fewer cassette spikes 161 than the maximum number of cassette spikes 161 are accessible when fewer than the maximum number of dialysate lines need to be used.

[0197] FIG. 23 shows an enlarged, exploded view of the connector end 30a of the dialysate line 30 with the cap 31 removed. (In FIG. 23, the cap 31 is shown without the thumb pull ring as shown in FIG. 24 for clarity. The pull ring is not required for operation of the cap 31 with the cycler 14; however, it may be useful in allowing an operator to manually remove the cap 31 from the terminal end of the dialysate line 30, if desired.) In this exemplary embodiment, the indicator in the indicator region 33 has an annular shape sized and configured to fit within a corresponding slot in the carriage 146 when installed as shown in FIGS. 10 and 11 . Of course, the indicator can be in any suitable form. The cap 31 is configured to fit over the leading edge of the connector end 30a, and it has an internal hole, seal, or other feature that allows for a leak-tight connection with the spike 160 on the cassette 24. Connector end 30a can include a penetrable wall or septum (not shown, see item 30b in FIG. 33) that prevents leakage of dialysate in line 30 from connector end 30a even when cap 31 is removed. The wall or septum can be penetrated by spike 160 when connector end 30a is attached to cassette 24, allowing flow from line 30 to cassette 24. As discussed above, cap 31 can include groove 31a that is engaged by fork-shaped element 60 of cap stripper 149. Cap 31 can further include hole 31b configured to receive spike cap 63. The holes 31b and caps 31 can be configured such that, with the cap stripper 149 engaged in the grooves 31a and the spike caps 63 of the spikes 160 received in the holes 31b, the caps 31 can adequately grip the spike caps 63, such that when the carriage 146 / cap stripper 149 pulls the caps 31 off the cassette 24, the spike caps 63 are detached from the spikes 160 and carried by the caps 31.This removal may be aided by rocker arm 61 engaging second flange 63a, as described above, or engaging other features on spike cap 63. Cap 31 and spike cap 63 may then be removed from connector end 30a and line 30, which are attached to spike 160 by carriage 146. [Dialysis fluid connector / heater] In one embodiment, a connector heater can be provided near the indicator region 33 of the dialysate line 30. The connector heater can control the temperature of the connector end 30a, particularly the piercing wall or septum 30b, to limit the carriage force required to attach the dialysate line to the spike 160 on the cassette 24. Ambient temperature (room temperature) fluctuations may be sufficient to affect the hardness of the piercing wall or septum 30b at the connector end 30a of the dialysate line, which in turn may affect the performance of the carriage 146 in joining the spike 160 to the connector end 30a of the dialysate line 30. For example, at lower ambient temperatures, the increased hardness of the piercing wall or septum 30b may require more force for the spike 160 to penetrate it. On the other hand, at higher ambient temperatures, the piercing wall or septum may be too flexible and may deform rather than separate upon contact with the spike 160.

[0198] The temperature of the connector end 30a can be controlled in a number of ways, which can include placing a heating element in an appropriate location (e.g., at or near location 2807 on the door 141), installing a temperature sensor to monitor the temperature of the connector end 30a, using a controller to receive the temperature data, and modulating the operation of the heating element. The temperature can be measured by a temperature sensor element located on the stripper element 1491 or on the carriage 146. Alternatively, the temperature of the connector end 30a can be determined using an infrared (IR) sensor tuned to measure the surface temperature of the connector end 30a.

[0199] The controller can be a software process in the automation computer 300. Alternatively, the controller can be implemented in the hardware interface 310. The controller can, for example, modulate the power sent to the resistive heater in one of a number of ways. For example, the controller can send a PWM signal to a MOSFET, which can modulate the power flow to the resistive heater. The controller can control the measured temperature to the desired temperature through a number of algorithms. One typical algorithm includes a proportional-integral (PI) feedback loop on the measured temperature to set the heater power. Alternatively, the heater power can be modulated with an open-loop algorithm that sets the heater power based on the measured ambient temperature.

[0200] In another embodiment, the temperature of connector end 30a can be controlled by mounting a radiant heater at location 2807 on door 141, e.g., aimed at the connector end. Alternatively, the temperature of the connector end can be controlled by mounting a thermoelectric element at location 2807, e.g., on door 141. The thermoelectric element, when mounted on carriage 146, can provide either heating or cooling to the area surrounding the connector end. The radiant heater or thermoelectric element can be modulated by a controller to maintain the temperature within a given range. The preferred temperature range for controller end 30a depends on the material comprising the piercing wall or septum and can be determined empirically. In one embodiment, the piercing wall is PVC, and the preferred temperature range is set to approximately 10°C to 30°C, more preferably approximately 20°C to 30°C.

[0201] In one embodiment, a connector heater near indicator area 33 can be activated after the door is closed and before the dialysate line 30 is attached to the cassette 24. If the measured temperature near connector 30a is outside of a desired range, the automation computer 300 or controller can enable the connector heater. The automation computer 300 or controller can delay the auto-connect process until the measured temperature is within a desired range. After the auto-connect process is complete, the connector heater can be disabled.

[0202] Once treatment is complete or the lines 30 and / or cassette 24 are ready to be removed from the cycler 14, the door 141 can be opened and the caps 31 and attached spike caps 63 can be reattached to the spikes 160 and lines 30 before the cassette 24 and lines 30 are removed from the cycler 14. Alternatively, the dialysate container with cassette 24 and lines 30 can be removed en bloc from the cycler 14 without reattaching the caps 31 and attached spike caps 63. Advantages of this approach include a simplified removal process and avoidance of any potential fluid leaks onto the cycler or into the surrounding area due to improperly reattaching or improperly sealing the caps.

[0203] Figures 24-32 show perspective views of the carriage 146, cap stripper 149, and cassette 24 during the line installation and auto-connect operation. The door 141 and other cycler components are not shown for clarity. In Figure 24, the carriage 146 is shown in a folded-down position, as if the door 141 were open in the position shown in Figure 8. The line 30 and cassette 24 are positioned to be lowered onto the door 141. In Figure 25, the line 30 is loaded onto the carriage 146, and the cassette 24 is loaded into the installation position 145. At this point, the door 141 can be closed to prepare the cycler for operation. In Figure 26, the door 141 is closed. Identifiers or indicators in the indicator area 33 on the line 30 can be read to identify various line characteristics, allowing the cycler 14 to determine, for example, which dialysate to load and how much. In FIG. 27, the carriage 146 moves leftward and engages the caps 31 on the line 30 with the corresponding spike caps 63 on the cassette 24. During operation, the drive element 133 engages the cap tripper 149, which in turn moves the cap stripper 149 leftward. However, the cap stripper 149 remains in the retracted position. In FIG. 28, the cap stripper 149 moves forward and engages the fork-shaped element 60 with the caps 31, thereby engaging the caps 31 coupled to the spike caps 63. If present, the rocker arm 61 can move to an engagement position relative to the spike caps 63. Next, as shown in FIG. 29, the carriage 146 and cap stripper 149 move rightward away from the cassette 24, thereby pulling the caps 31 and spike caps 63 from the corresponding spikes 160 on the cassette 24. It is possible that during this movement, the rocker arm 61 (if present) assists in pulling the spike cap 63 from the cassette 24. In Figure 30, the cap stripper 149 stops its movement to the right and the carriage 146 continues to move away from the cassette 24.This pulls the connector end 30a of the line 30 from the cap 31, leaving the cap 31 and spike cap 63 attached to the cap stripper 149 by the fork-shaped element 60. In FIG. 31, the cap stripper 149 retracts, clearing the path for the carriage 146 to move toward the cassette 24 again. In FIG. 32, the carriage 146 moves toward the cassette 24, engaging the connector end 30a of the line 30 with the corresponding spike 160 on the cassette 24. The carriage 146 may remain in this position during cycler operation. Once treatment is complete, the operations shown in FIGS. 24-32 can be reversed to re-cap the spike 160 and dialysate line 30 and remove the cassette 24 and / or line 30 from the cycler 14.

[0204] To further illustrate the removal of the cap 31 and spike cap 63, FIG. 33 shows cross-sectional views of the cassette 24 at five different stages of line 30 connection. At the top spike 160, the spike cap 63 is still in place on the spike 160, as in FIG. 26, and the dialysate line 30 is positioned away from the cassette 24. At the second spike 160, from top to bottom, as in FIGS. 27 and 28, the dialysate line 30 and cap 31 engage over the spike cap 63. At this point, the cap stripper 149 can engage the cap 31 and spike cap 63. At the third spike 160, from the top, the dialysate line 30, cap 31, and spike cap 63 have been moved away from the cassette 24, as in FIG. 29. At this point, the cap stripper 149 can stop moving to the right. At the fourth spike 160, from above, the dialysate line 30 continues to move to the right, as in FIG. 30, removing the cap 31 from the line 30. Once the caps 31 and 63 are retracted, the dialysate line 30 moves to the left, as in FIG. 32, fluidly connecting the connector end 30a of the line 30 to the spike 160.

[0205] Various sensors can be used to help verify that the carriage 146 and cap stripper 149 move fully to their expected positions. In one embodiment, the carriage drive assembly 132 can be equipped with six Hall effect sensors (not shown), four for the carriage 146 and two for the cap stripper 149. A first cap stripper sensor can be positioned to detect when the cap stripper 149 is fully retracted. A second cap stripper sensor can be positioned to detect when the cap stripper 149 is fully extended. The first carriage sensor can be positioned to detect when the carriage 146 is in a "home" position, i.e., a position that allows for loading of the cassette 24 and line 30. The second carriage sensor can be positioned to detect when the carriage 146 is positioned to engage the spike cap 63. The third carriage sensor can be positioned to detect when the carriage 146 has reached a position to remove the cap 31 from the line 30. A fourth carriage sensor can be positioned to detect when the carriage 146 moves into a position that engages the connector end 30a of the line 30 with a corresponding spike 160 on the cassette 24. In other embodiments, a single sensor can be used to detect two or more of the above-mentioned carriage positions. The cap stripper and carriage sensors can provide input signals to the electronic control board (autoconnect board), which can in turn communicate certain confirmations or error codes to the user via the user interface 144.

[0206] FIG. 11-6 shows a perspective view of another embodiment of the carriage drive assembly 132. In the embodiment shown in FIG. 12, the carriage drive assembly 132 only includes the drive element 133, the rod 134, the tab 135, and the window 136. In the embodiment of FIG. 11-6, the carriage drive assembly 132 includes not only the drive element 133, the rod 134, the tab 135, and the window 136, but also a vertical row of Auto ID view boxes 1116. The view boxes 1116 can be positioned directly adjacent to the windows 136. The view boxes 1116 can also be positioned and shaped so that the horizontal axes of each of the five slots 1086 located on the carriage 146 pass through the center of the corresponding view box 1116 when the carriage 146 moves either right or left along the guide 130. The view box 1116 may enable the Auto-ID camera 1104 mounted on the camera board 1106 to detect whether the dialysate line cap 31 is placed on the line 30 before the dialysate line engages the spike cap 63. This may allow confirmation that the user has not prematurely removed the cap 31. Once the presence or absence of the cap 31 is determined, the camera 1104 may provide a corresponding input signal to the electronic control board (referred to herein as the autoconnect board), which may in turn communicate a specific confirmation or error code regarding the presence of the cap 31 on the line 30 to the user via the user interface 144.

[0207] In accordance with another aspect of the present invention, the carriage drive assembly 132 may include an autoconnect board 1118. The autoconnect board 1118 may be attached to the top of the carriage drive assembly 132 and may extend the overall length of the assembly 132. In this exemplary embodiment, an LED 1120 may be further attached to the autoconnect board 1118. The LED 1120 may be positioned in a fixed position directly above the fork-shaped element 60 and may be oriented such that light emitted from the LED 1120 travels downward across the stripper element 1491. In accordance with another aspect of the present invention, the carriage drive assembly 132 may further include a fluidic board 1122. The fluidic board 1122 may be attached to the bottom of the carriage drive assembly 132 and may extend the length of the assembly 132. In this exemplary embodiment, a receiver 1124 (not shown) can be attached to the fluidic substrate 1122 directly below the LED 1120, which is attached to the autoconnect substrate 1118. Thus, the LED 1120 can emit light across the fork-shaped element 60; if the light is detected by the receiver 1124, no dialysate line cap 31 is left on the stripper element 1491; however, if the light is blocked on its way to the receiver 1124, a cap 31 may be left on the stripper element 1491. This combination of the LED 1120 and receiver 1124 allows for detection of a cap 31 that may be inadvertently left on the stripper element 1491 by a user or the cycler 14. According to aspects of the present invention, the fluidic substrate 1122 can further be capable of detecting humidity, moisture, or other liquids that may be present inside the carriage drive assembly 132 and potentially cause the cycler 14 to malfunction.

[0208] It may be advantageous to adjust the force with which the carriage 146 engages the spike cap 63 depending on how many lines 30 are installed. The force required to complete a connection to the cassette 24 increases with the number of caps 31 that must be coupled to the spike cap 63. A detection device that detects and reads information from the line indicator in the indicator area 33 can also be used to provide the data necessary to adjust the force applied to the drive element 133. The force can be generated by a number of devices, including, for example, the first bladder 137 or a linear actuator such as a motor / ball screw. An electronic control board (e.g., an autoconnect board) can be programmed to receive input from the line detection sensor and send appropriate control signals to either the linear actuator motor or the pneumatic valve controlling the inflation of the bladder 137. The controller 16 can control the extent or speed of movement of the drive element 133, for example, by adjusting the voltage applied to the linear actuator motor or by adjusting the pneumatic valve controlling the inflation of the bladder 137.

[0209] According to aspects of the present invention, it may be necessary for the carriage drive assembly 132 to be able to generate at least 550 N (124 lbf) of force on the carriage 146 to engage the membrane port with the spike 160. This force is measured for spiking of the membrane port onto the cassette 24 in the direction of the carriage. The maximum force required to stab a sterile PVC membrane port onto the spike 160 may be 110 N. Additionally, the maximum force required to stab a sterile JPOC membrane port onto the spike 160 may be 110 N. These force requirements ensure that the carriage drive assembly 132 can stab five JPOC ports. In other embodiments, the force requirements for the PVC ports can be further reduced based on the current insertion force.

[0210] In addition to simplicity of operation, embodiments of the present invention in which caps 31 on lines 30 are removed along with caps 63 on spikes 160 of cassette 24 may have other advantages. For example, because spike caps 63 are removed by their engagement with caps 31 on lines 30, if there is no line 30 attached to a particular slot on carriage 146, the spike cap 63 will not be removed at that location. For example, cassette 24 may include five spikes 160 and corresponding spike caps 63, but the cycler 14 may operate with four or fewer lines 30 (or even none) associated with the cycler 14. Those slots on carriage 146 where no line 30 exists do not have caps 31 and therefore no mechanism by which the spike caps 63 can be removed at that location. In this manner, if there is no line 30 connected to a particular spike 160, the cap 63 on that spike 160 can remain in place during use of cassette 24. This can help prevent leakage at the spike 160 and / or contamination at the spike 160 .

[0211] The cassette 24 in FIG. 33 includes a few features that differ from those shown in the embodiments shown in, for example, FIGS. 3, 4, and 6. In the embodiments of FIGS. 3, 4, and 6, the heater bag port 150, the outlet line port 152, and the patient line port 154 are configured with a central tube 156 and a skirt 158. However, as described above and shown in FIG. 33, the ports 150, 152, and 154 can include only the central tube 156 and no skirt 158. This is also shown in FIG. 34. The embodiment shown in FIG. 34 includes a raised rib formed on the exterior surface of the left pump chamber 181. A raised rib can also be provided on the right pump chamber 181 to provide a feature in the door 141 at the cassette mounting location 145 with an additional contact point on the exterior wall of the pump chamber 181, which presses the cassette against the control surface 148 when the door 141 is closed. Raised ribs are not required; instead, pump chamber 181 may have no ribs or other features, as shown for right pump chamber 181 in FIG. 34. Similarly, spike 160 in the embodiments of FIGS. 3, 4, and 6 does not include a skirt or similar feature at the base of spike 160, while the embodiment in FIG. 33 includes skirt 160a, also shown in FIG. 34. Skirt 160a can be positioned to receive the end of spike cap 63 in the recess between skirt 160a and spike 160, helping to form a seal between spike 160 and spike cap 63.

[0212] Another inventive feature shown in FIG. 33 relates to the placement of the distal tip of spike 163 and lumen 159 through spike 160. In this embodiment, the distal tip of spike 160 is positioned at or near a longitudinal axis of spike 160 that runs generally along the geometric center of spike 160. Locating the distal tip of spike 160 at or near the longitudinal axis can help alleviate positioning tolerances when engaging spike 160 with a corresponding dialysate line 30 and aid in spike 160 piercing the septum or membrane 30b at the connector end 30a of line 30. As a result, lumen 159 of spike 160 is positioned generally offset from the longitudinal axis of spike 160 near the base of spike 160, for example, as shown in FIG. 33 and in the end view of spike 160 in FIG. 35. Also, the tip of spike 160 has a somewhat reduced diameter compared to the closer portion of spike 160 (in this embodiment, spike 160 actually has a step change in diameter from body 18 about two-thirds of the way down the length of spike 160). The reduced diameter of spike 160 at the tip can provide clearance between spike 160 and the inner wall of line 30, thus giving septum 30b space to fold back and locate between spike 160 and line 30 when penetrated by spike 160. Step feature 160b on spike 160 (e.g., shown in FIG. 35A) can also be positioned to engage line 30 in a position that connects septum 30b to the inner wall of line 30, thereby improving the seal formed between line 30 and spike 160.

[0213] In another embodiment, as shown in FIG. 35A , the length of the base portion 160c of the spike 160 can be shortened, thereby reducing the force required to remove the spike cap 63 from the spike 160 or to hammer it into the connector end 30a of the dialysate line 30. Shortening the base portion 160c reduces the area of ​​frictional contact between the spike 160 and its cap 63 or between the spike 160 and the inner surface of the connector end 30a. In addition, the skirt 160a at the base of the spike 160 can be replaced with a separate post 160d. The post 160d allows the spike cap 63 to properly seat on the spike 160 and allows for more complete circulation of sterile fluid or gas around the spike 160 during sterilization procedures before and after packaging of the dialysate supply set 12.

[0214] To more fully utilize the embodiment shown in FIG. 35A, a spike cap 64 as shown in FIG. 35B can be used. A skirt 65 on the base of the spike cap 64 is constructed to fit snugly over the post 160d of the base of the spike 160 shown in FIG. 35A. In addition, intermittent ribs 66 and 67 around the interior periphery of the base of the spike 160 can provide a snug fit between the spike cap 64 and the base 160c of the spike 160, while allowing sterilizing gas or fluid to penetrate further across the base of the capped spike 160. As shown in FIG. 35C, in a cross-sectional view of the spike cap 64, a set of three interior ribs 66, 67, and 68 can be used to provide a snug fit between the spike cap 64 and the base 160c of the spike 160. In one embodiment, ribs 66 and 67 have interruptions or gaps 66a and 67a along their periphery to allow gas or fluid outside the cassette to flow over base portion 160c of spike 160. Third rib 68 is free of circumferential imperfections to provide a sealing engagement between spike cap 64 and base portion 160c of spike 160, sealing base portion 160c from the remainder of the exterior surface of spike 160. In other embodiments, the ribs in spike cap 64 may be oriented longitudinally rather than circumferentially, or in other orientations that provide a snug fit between spike cap 64 and spike 160 while allowing external gas or fluid to contact the outside of base portion 160c of spike 160. In the illustrated embodiment, for example, the exterior surfaces of the cassette, spike cap, and most of the base portion 160c of spike 160 can be sterilized by exposing the exterior of the cassette to ethylene oxide gas. The diameter of the stepped feature 160b and the tip of the spike 160 is smaller than the inner diameter of the overlapping portion of the spike cap 64, so that any gas or fluid that enters the spike lumen from the interior of the cassette can reach the outer surface of the spike 160 up to the sealing rib 68.In this manner, any sterilizing gas, such as ethylene oxide, that enters the fluid passages of the cassette can reach the remainder of the outer surface of spike 160. In one embodiment, gas can enter the cassette through a vent cap on the end of patient line 34 or outlet line 28, for example.

[0215] The spike cap 34 can have three or more centering ribs 64D that contact the ends of the spikes 160. The ribs 64D are oriented along the main access portion of the spike cap 34 and are positioned near the closed end of the spike cap 34. Preferably, there are at least three ribs 63D to center the closed end of the cap over the spike without overly constraining the cap / spike orientation. The spike cap 34 has a tapered end with a blunt tip to facilitate penetration of the spike cap 34 into the hole 31b of the dialysate cap 31. The tapered end will guide the spike cap 34 if it is misaligned with the hole 31b. The blunt tip catches the inner edge of the hole 31b and avoids snagging of the dialysate cap 31, unlike a sharp tip that may be dug into the dialysate cap material. In contrast, the blunt tip can slide through the edge of the hole 31b.

[0216] Once the cassette 24 and lines 30 are loaded into the cycler 14, the cycler 14 must control the operation of the cassette 24 to move fluid from the dialysate lines 30 to the heater bag 22 and the patient. FIG. 36 shows a plan view of a control surface 148 of the cycler 14 that interacts with the pump chamber side of the cassette 24 (e.g., as shown in FIG. 6) to control fluid pumping and fluid paths within the cassette 24. When at rest, the control surface 148, which may be described as a type of gasket and may comprise a silicone rubber sheet, may be generally flat. A valve control area 1481 may be defined (or not) in the control surface 148 by, for example, scoring, grooves, ribs, or other features in or on the surface of the sheet, and may be positioned to be movable generally transverse to the plane of the sheet. By moving inward / outward, the valve control area 1481 can move an associated portion of the membrane 15 on the cassette 24, thereby opening or closing the respective valve ports 184, 186, 190, and 192 of the cassette 24 and thus controlling flow within the cassette 24. Two larger areas (pump control areas 1482) can similarly move, thereby moving an associated shaped portion 151 of the membrane 15 that cooperates with the pump chamber 181. Like the shaped portion 151 of the membrane 15, the pump control area 1482 can be shaped to correspond to the shape of the pump chamber 181 when the control area 1482 expands into the pump chamber 181. In this way, the portion of the control sheet 148 at the pump control area 1482 does not necessarily have to stretch or elastically deform during pump operation.

[0217] Each of regions 1481 and 1482 may have an associated vacuum or evacuation port 1483 that may be used, for example, to remove all or substantially all of any air or other fluid that may be present between membrane 15 of cassette 24 and control surface 148 of cycler 14 after cassette 24 is loaded into cycler 14 and door 141 is closed. This may help ensure intimate contact of membrane 15 with control regions 1481 and 1482 and help control the delivery of a desired volume through pumping and / or the open / closed status of various valve ports. Note that vacuum port 1482 is formed in a location where control surface 148 is not forced into contact with the wall of cassette 24 or other relatively rigid features. For example, according to one aspect of the present invention, one or both of the pump chambers of a cassette may include a vacuum vent clearance region formed adjacent to the pump chamber. In this exemplary embodiment as shown in FIGS. 3 and 6 , the base member 18 can include a vacuum vent port clearance or extension feature 182 (e.g., a recessed area fluidly connected to the pump chamber) adjacent to and outside of the oval-shaped recess that forms the pump chamber 181, thereby allowing the vacuum vent port 1483 for the pump control region 1482 to remove any air or fluid from between the membrane 15 and the control surface 148 (e.g., by rupturing the membrane 15) without interference. The extension feature can also be located within the confines of the pump chamber 181. However, locating the vent port feature 182 outside the perimeter of the pump chamber 181 can ensure a larger pump chamber volume for pumping fluid, for example, allowing the maximum footprint of the pump chamber 181 to be used to pump dialysate. Preferably, extension feature 182 is positioned vertically lower relative to pump chamber 181 so that any liquid that leaks between membrane 15 and control surface 148 is drawn as soon as possible through vacuum port 1483. Similarly, vacuum port 1483 associated with valve 1481 is preferably positioned vertically lower relative to valve 1481.

[0218] 36A shows that control surface 148 may be constructed or molded to have rounded transitions between its base element 1480 and its valve and pump control areas 1481, 1482. Junctions 1491 and 1492 can be molded with small radii to transition from base element 1480 to valve control area 1481 and pump control area 1482, respectively. Rounded or smooth transitions can help prevent premature fatigue and failure of the materials comprising control surface 148, extending its lifespan. In this embodiment, channel 1484 leading from vacuum port 1483 to pump control area 1482 and valve control area 1481 may need to be lengthened somewhat to accommodate the transition features.

[0219] Control areas 1481 and 1482 may be moved by controlling air pressure and / or volume on the side of cassette 24 opposite control surface 148 (e.g., behind the rubber sheet forming control surface 148). For example, as shown in FIG. 37, control surface 148 may have control chambers 171 associated with each of control areas 1481, 1482, and be backed by mating blocks 170 that are spaced apart from one another (or, if desired, can at least be controlled independently of one another). The surface of mating block 170 forms an interface with cassette 24 when cassette 24 is pressed against it and moves in relation to control surface 148 that is backed by mating block 170. Thus, the control chamber of mating block 170 is coupled to a complementary valve or pump chamber of cassette 24, sandwiching control areas 1481 and 1482 of control surface 148 adjacent mating block 170 and associated areas (such as shaped portion 151) of membrane 15 adjacent cassette 24. Air or other control fluid can flow in and out of control chamber 171 of mating block 170 for areas 1481, 1482, thereby moving control areas 1481 and 1482 as desired to open or close valve ports of cassette 24 and / or achieve pumping action in pump chamber 181. In one exemplary embodiment shown in FIG. 37, control chamber 171 can be arranged as a cylindrically shaped area abutting the back surface of each of valve control areas 1481 and a pair of elliptical cavities abutting the back surface of pump control area 1482. A fluid control port can be provided in each control chamber 171 such that the cycler 14 can control the volume of fluid and / or the pressure of fluid in each of the control chambers. For example, the mating block 170 can be mated to a manifold 172 that includes various ports, channels, openings, voids, and / or other features that communicate with the control chambers 171 and allow the appropriate air pressure / vacuum to be applied to the control chambers 171. Although not shown, control of the air pressure / vacuum can be done in any suitable manner, such as through the use of controllable valves, pumps, pressure sensors, accumulators, etc.Of course, it should be understood that the control regions 1481, 1482 may be moved in other ways, such as by gravitational, hydraulic, and / or mechanical systems (such as by linear motors), or by a combination of systems including pneumatic, hydraulic, gravitational, and mechanical systems.

[0220] FIG. 37A shows an exploded view of an integrated pressure distribution module or assembly 2700 for use in a fluid flow control device for operating a pumping cassette and suitable for use as the pressure distribution manifold 172 and interface block 170 of the cycler 14. FIG. 37B shows a diagram of the integrated module 2700 including a pneumatic manifold or block, ports for supply pressure, pneumatic control valves, pressure sensors, a pressure supply or interface block, and a control surface or actuator with a region containing a flexible membrane for actuating the pump and valves on the pumping cassette. The integrated module 2700 can also include a reference chamber within the pneumatic manifold for FMS volumetric processing to determine the volume of fluid present in the pumping chamber of the pumping cassette. The integrated module can also include a vacuum port and a pathway or channel from the interface between the actuator and the flexible pump, and a set of valve membranes on the pumping cassette to a fluid trap and liquid detection system. In some embodiments, the pneumatic manifold can be formed as a single block. In other embodiments, the pneumatic manifold can be formed from two or more manifold blocks joined together with a gasket disposed between the manifold blocks. The integrated module 2700 occupies a relatively small space in the fluid flow control device and eliminates the use of tubing or flexible conduits connecting manifold ports with corresponding ports on a pressure supply module or block joined to the pumping cassette. Among possible advantages, the integrated module 2700 can reduce the size and assembly cost of the pneumatic actuation assembly of the peritoneal dialysis cycler, resulting in a smaller and less expensive cycler. Additionally, the short distance between the pressure or vacuum distribution ports on the pressure distribution manifold block and the corresponding pressure or vacuum supply ports on the joined pressure supply block, combined with the stiffness of the conduits connecting the ports, can improve the responsiveness of the attached pumping cassette and the accuracy of the cassette pump volume measurement process.When used in a peritoneal dialysis cycler 14, in one embodiment, an integrated module with a metal pressure distribution manifold bonded directly to a metal pressure supply block can also reduce any temperature difference between the control volume 171B and the reference chamber 174 of the cycler 14, which can improve the accuracy of the pump volume measurement process.

[0221] An exploded view of the integrated module 2700 is shown in FIG. 37A. The actuator face mounted on the junction block or pressure supply block resembles or is equivalent to a gasket or control face 148, with a flexible area positioned to move back and forth to pump fluid and / or open and close a valve by pushing or pulling on the membrane 15 of the pump cassette 24. For the cycler 14, the control face 148 is actuated by pneumatic positive and negative forces supplied to the control volumes 171A, 171B behind the control areas 1481, 1482. The control face 148 is attached to the pressure supply block or junction block 170 by tightly mating with a lip 2742 on a raised surface 2744 on the forward face of the junction block 170. The interface block 170 can include one or more surface recesses 2746 to align with and support the oval curved shape of one or more corresponding pump control surfaces 1482, forming the pump control chamber. A similar configuration, with or without a surface recess, can be included to form the valve control region 171A for alignment with corresponding control surfaces 1481 for controlling one or more valves of the pumping cassette. The interface block 170 can also include grooves 2748 in the surface of the recesses 2746 of the interface block 170 behind the pump control surface 1482 to facilitate flow of control fluid or gas from the ports 173C to the entire backside of the pump control surface 1482. Alternatively, rather than having grooves 2748, the recesses 2746 can be formed with a roughened or tangentially porous surface.

[0222] Junction block 170 connects pressure distribution manifold 172 to control surface 148, supplying pressure or vacuum to the various control areas on control surface 148. Junction block 170 can also be referred to as a pressure supply block, in that it supplies pressure and vacuum to valve control area 1481 and pump control area 1482, supplies vacuum to vacuum port 1483, and provides pneumatic conduits for supplying connections from pump control volume 171B to the pressure sensor. Port 173A connects valve control volume 171A to pressure distribution manifold 172. Port 173C connects pump control volume 171B to pressure distribution manifold 172. Vacuum port 1483 is connected to pressure distribution manifold 172 via port 173B. In one embodiment, port 173B extends above the surface of pressure supply block 170 and passes through control surface 148 to provide a vacuum at port 1483 without pulling control surface 148 onto port 173B and without blocking flow.

[0223] The pressure supply block 170 is attached to the front of the pressure distribution manifold 172. Ports 173A, 173B, and 173C are aligned with the pneumatic circuit on the pressure distribution manifold 172, which connects to valve port 2714. In one example, the pressure supply block 170 is joined to the pressure distribution manifold 172 with a front flat gasket 2703 secured therebetween. The block 170 and manifold 172 are held together mechanically, in some embodiments, through the use of bolts 2736 or other types of fasteners. In another example, rather than a flat gasket 2703, a standard-compliant element is placed on or molded into either the pressure supply block 170 or the pressure distribution manifold 172. Alternatively, the pressure supply block 170 can be joined to the pressure distribution manifold 172 by adhesive, double-sided tape, friction welding, laser welding, or other joining methods. The block 170 and manifold 172 can be made of metal or plastic, and the method of attachment will vary depending on the material.

[0224] The pressure distribution manifold 172 includes ports for pneumatic valves 2710, reference chamber 174, fluid trap 1722, and pneumatic circuitry, or, as in the integrated module 2700, ports 2714 that provide pneumatic connections between the valves and accumulators and receive multiple cartridge valves 2710. The cartridge valves 2710 include, but are not limited to, binary valve 2660, which controls flow to valve-controlled volume 171A; binary valves X1A, X1B, X2, and X3, which control flow to pump-controlled volume 171B; and binary valves 2661-2667, which control flow to bladders 2630, 2640, and 2650 and accumulators 2610 and 2620. The cartridge valves 2710 are pushed into valve ports 2714 and electrically connected to the hardware interface 310 via circuit board 2712.

[0225] The pneumatic circuits in the pressure distribution manifold 172 can be formed by a combination of grooves or slots 1721 on the front and back sides and generally perpendicular holes connecting the grooves 1721 on one side to the valve ports 2714, fluid traps 1722, and grooves and ports on the opposite side. Some grooves 1721 can be directly connected to the reference chamber 174. A single perpendicular hole can connect the grooves 1721 to multiple closely spaced and staggered valve ports 174. In one example, a sealed pneumatic conduit is formed when the grooves 1721 are separated from each other by a front flat gasket 2703, as shown in FIG. 37A.

[0226] The presence of liquid in fluid trap 1722 can be detected by a pair of conductivity probes 2732. Conductivity probes 2732 slide through back gasket 2704, back plate 2730, and holes 2750 before entering fluid trap 1722 in pressure distribution manifold 172.

[0227] The back plate 2730 seals the reference volume 174, the groove 1721 on the back side of the pressure distribution manifold 172, and provides ports for the pressure sensor 2740 and ports for the pressure and vacuum lines 2734, and a vent to atmosphere 2732. In one example, the pressure sensor can be an IC chip soldered to a single substrate 2740 and pressed as a group against a back gasket 2704 on the back plate 2730. In one example, bolts 2736 secure the back plate 2730, pressure distribution manifold 172, and pressure supply block 170 together with the gaskets 2703, 2702 therebetween. In another example, the back plate 2730 can be coupled to the pressure supply manifold 172 mentioned above. The assembled integrated module 2700 is shown in FIG.

[0228] Figure 37C shows a schematic of the pneumatic circuitry in the integrated manifold 2700 and the pneumatic elements outside the manifold. Pump 2600 generates vacuum and pressure. Pump 2600 is connected to vent 2680 and negative pressure or vacuum reservoir 2610 and positive pressure reservoir 2620 via three-way valves 2664 and 2665. The pressure in positive pressure and negative pressure reservoirs 2620 and 2610 is measured by pressure sensors 2678 and 2676, respectively. Hardware interface 310 controls the speed of pump 2600 and the position of three-way valves 2664, 2665, and 2666 to control the pressure in each reservoir. Auto-connect stripper element bladder 2630 is connected to either positive pressure line 2622 or negative pressure or vacuum line 2612 via three-way valve 2661. Automation computer 300 commands the position of valve 2661 to control the position of stripper element 1461. Occlusion bladder 2640 and piston bladder 2650 are connected to either pressure line 2622 or vent 2680 via three-way valves 2662 and 2663. Automation computer 300 commands valve 2663 to connect the piston bladder to pressure line 2622 after door 141 is closed, firmly engaging cassette 24 against control surface 148. Occlusion bladder 2640 is connected to pressure line 2622 via valve 2662 and restriction 2682. Occlusion bladder 2640 is connected to vent 2680 via valve 2662. Orifice 2682 indicates filling of occlusion bladder 2640, which advantageously retracts occlusion 147 and maintains pressure in pressure line 2622. High pressure in pressure line 2622 keeps the various valve control surfaces 171A and piston bladders actuated against cassette 24, which prevents flow to and from the patient as occlusion 147 opens. Conversely, the connection from occlusion bladder 2640 to vent 2680 is unrestricted, allowing occlusion 147 to close quickly.

[0229] Valve control surface 1481 is controlled by the pressure in valve control volume 171A, which in turn is controlled by the position of three-way valve 2660. Valve 2660 can be individually controlled via commands from automation computer 300 passed through hardware interface 310. The valve controlling the pumping pressure in pump control volume 171B is controlled by two-way valves X1A and X1B. Valves X1A and X1B can, in one example, be controlled by hardware interface 310 to achieve the pressure commanded by automation computer 300. The pressure in each pump control chamber 171B is measured by sensor 2672. The pressure in the reference chamber is measured by sensor 2670. Two-way valves X2 and X3 connect reference chamber 174 to pump control chamber 171B and vent 2680, respectively.

[0230] Fluid trap 2622 is to vacuum line 2612 during operation as described elsewhere in this application. The fluid trap is connected by several lines to port 173B in pressure supply block 170. The pressure in the fluid trap is monitored by pressure sensor 2674 mounted on back plate 2730.

[0231] The vacuum port 1483 can be used to separate the membrane 15 from the control surface 148 at the end of treatment, before or while the door is open. Vacuum provided by a negative pressure source to the vacuum port 1483 tightly engages the membrane 15 with the control surface 148 during treatment. In some instances, even when the application of vacuum is discontinued, a substantial amount of force may be required to separate the control surface from the cassette membrane 15 and prevent the door 141 from freely rotating to the open position. Accordingly, in certain embodiments, the pressure distribution module 2700 is configured to provide a valved channel between the positive pressure source and the vacuum port 1483. The application of positive pressure at the vacuum port helps separate the membrane 15 from the control surface 148, thereby allowing the cassette 24 to be more easily separated from the control surface 148 and the door 141 to open freely. A pneumatic valve in the cycler can be controlled by the automation computer 300 to provide positive pressure to the vacuum port 1483. Manifold 172 may be equipped with separately valved channels dedicated for this purpose, or alternatively, it may employ existing channel configurations and valves that are operated in a particular sequence.

[0232] In one example, the vacuum port 1483 can be supplied with positive pressure by temporarily connecting the vacuum port 1483 to a positive pressure reservoir 2620. During treatment, the vacuum port 1483 is normally connected to the vacuum reservoir 2610 through a common fluid collection chamber or fluid trap 1722 in the manifold 172. In one example, the controller or automation computer can simultaneously open valve X1B between the positive pressure reservoir and volume control chamber 171B and valve X1A between the negative pressure reservoir and the same volume control chamber 171B, which will pressurize the air in the fluid trap 1722 and vacuum port 1483. The pressurized air flows through the vacuum port 1483 between the membrane 15 and the control surface 148, breaking any vacuum connection between the membrane and the control surface. However, in the manifold shown, the stripper element 1491 of the cap stripper 149 can be extended while positive pressure is supplied to the fluid in the common fluid collection chamber 1722. 1B. The stripper element 1491 is now connected to the control surface 148 after the fluid trap 1722 is depressurized because the stripper bladder 2630 is connected to the vacuum supply line 2612. In this example, in a subsequent step, the fluid trap 1722 is valved out of the now pressurized vacuum line, and the two valves X1A, X1B connecting the positive pressure and vacuum reservoirs to the volume control chamber 171B can be closed. The vacuum pump 2600 is then operated to reduce the pressure in the vacuum reservoir 2610 and the vacuum supply line 2612, which in turn allows the stripper element 1491 to be retracted. The cassette 24 can then be detached from the control surface 148, and the door 141 can be opened after the stripper element 1491 has been retracted.

[0233] According to an embodiment of the present invention, the vacuum port 1483 can be used to detect leaks in the membrane 15; for example, a liquid sensor in a conduit or chamber connected to the vacuum port 1483 can detect liquid if the membrane 15 is punctured or if liquid is introduced between the membrane 15 and the control surface 148. For example, the vacuum port 1483 can be positioned and sealingly associated with a complementary vacuum port 173 in the mating block 170, which in turn can be sealingly associated with a fluid passage 1721 leading to a common fluid collection chamber 1722 in the manifold 172. The fluid collection chamber 1722 can include an inlet through which vacuum can be applied and distributed to all of the vacuum ports 1483 on the control surface 148. By applying a vacuum to the fluid collection chamber 1722, fluid can be drawn from each of the vacuum ports 173 and 1483, thus removing fluid from any space between the membrane 15 and the control surface 148 in the various control regions. However, if liquid is present in one or more of the regions, the associated vacuum port 1483 can draw the liquid into the vacuum port 173 and into the line 1721 leading to the fluid collection chamber 1722. Any such liquid can be collected in the fluid collection chamber 1722 and detected by one or more suitable sensors (e.g., a pair of conductivity sensors that detect a change in conductivity within the chamber 1722, indicating the presence of liquid). In this embodiment, the sensors can be located on the bottom side of the fluid collection chamber 1722, and the vacuum source connects to the chamber 1722 at its top. Thus, if liquid is drawn into the fluid collection chamber 1722, the liquid can be detected before the liquid level reaches the vacuum source. Optionally, a hydrophobic filter, valve, or other component can be located at the vacuum source connection to the chamber 1722 to help further resist fluid ingress into the vacuum source. In this way, liquid leaks can be detected and acted upon by the controller 16 (e.g., issuing an alarm, closing the liquid inlet valve, and stopping pump operation) before the vacuum source valve is at risk of being contaminated by the liquid.

[0234] In one embodiment, the inner walls of the control chamber 171 may include raised elements somewhat similar to the pump chamber spacer elements 50, as shown, for example, in FIG. 37 for the control chamber 171 associated with the pump control region 1482. These raised elements may be in the form of plateau-shaped features, ribs, or other protrusions that recess the control ports away from the fully retracted control region 1482. This configuration may allow for more even distribution of pressure or vacuum in the control chamber 171 and may prevent premature closure of any control ports by the control surface 148. The preformed control surface 148 (at least in the pump control region) may not be subjected to significant stretching forces when fully extended against either the inner walls of the pump chamber of the cassette 24 during a feed stroke or the inner walls of the control chamber 171 during a fill stroke. Thus, the control region 1482 may extend asymmetrically into the control chamber 171, causing the control region 1482 to prematurely close one or more ports in the control chamber before the chamber is completely emptied. Having features on the interior surface of the control chamber 171 that prevent contact between the control region 1482 and the control ports can help ensure that the control region 1482 can make uniform contact with the control chamber interior wall during the fill stroke.

[0235] As alluded to above, the cycler 14 may include a control system 16 having a data processor in electrical communication with the various valves, pressure sensors, motors, etc. of the system, preferably configured to control such components according to a desired operational sequence or protocol. The control system 16 may include appropriate circuitry, programs, computer memory, electrical connections, and / or other components to perform designated tasks. The system may include pumps, tanks, manifolds, valves, or other components to create the desired air or other fluid pressure (either a positive pressure above atmospheric pressure or some other reference pressure, or a negative pressure or vacuum below atmospheric pressure or some other reference pressure) to thereby control the operation of the control surface 148 area and other pneumatically operated components. Further details regarding the control system 16 (or at least portions thereof) are provided below.

[0236] In one exemplary embodiment, the pressure in the pump control chamber 171 can be controlled by a binary valve, e.g., it opens to expose the control chamber 171 to an appropriate pressure / vacuum and closes to shut off the pressure / vacuum source. The binary valve can be controlled using a sawtooth-shaped control signal, which can be modulated to control the pressure in the pump control chamber 171. For example, during a pump delivery stroke (i.e., when positive pressure is introduced into the pump control chamber 171, moving the membrane 15 / control surface 148 and forcing liquid out of the pump chamber 181), the binary valve is driven by the sawtooth signal to open and close at a relatively fast rate to establish an appropriate pressure in the control chamber 171 (e.g., a pressure of approximately 70-90 mmHg). If the pressure in the control chamber 171 is increased above approximately 90 mmHg, the sawtooth signal can be adjusted to close the binary valve for a longer period of time. If the pressure in control chamber 171 drops below about 70 mmHg, the sawtooth control signal can again be applied to the binary valve to increase the pressure in control chamber 171. Thus, during typical pump operation, the binary valve can be opened and closed multiple times and closed for one or more extended periods so that the pressure at which liquid is forced out of pump chamber 181 is maintained at a desired level or range (e.g., about 70-90 mmHg).

[0237] In some embodiments, and according to aspects of the present invention, it may be useful to detect the "end of stroke" of the membrane 15 / pump control region 1482, for example, when the membrane 15 contacts the spacer 50 in the pump chamber 181 or the pump control region 1482 contacts the wall of the pump control chamber 171. For example, during pump operation, detecting the "end of stroke" may indicate that the membrane 15 / pump control region 1482 movement should be reversed to begin a new pump cycle (filling the pump chamber 181 or driving fluid from the pump chamber 181). In one exemplary embodiment in which the pressure in the control chamber 171 for the pump is controlled by a binary valve driven by a sawtooth control signal, the pressure in the pump chamber 181 fluctuates at a relatively high frequency (e.g., at or near the frequency at which the binary valve is opened and closed). A pressure sensor in the control chamber 171 can detect this fluctuation, which generally has a higher amplitude when the membrane 15 / pump control area 1482 is not in contact with the inner wall of the pump chamber 181 or the wall of the pump control chamber 171. However, once the membrane 15 / pump control area 1482 contacts the inner wall of the pump chamber 181 or the wall of the pump control chamber 171 (i.e., "end of stroke"), the pressure fluctuation generally is damped or changes in a manner that is detectable by the pressure sensor in the pump control chamber 171. This change in pressure fluctuation can be used to identify the end of stroke and the pump and other components of the cassette 24 and / or cycler 14 can be controlled accordingly.

[0238] In one embodiment, the air pressure applied to the control chamber 171B is actively controlled by a processor that receives signals from a pressure transducer 2672 (FIG. 37C) connected to the control chamber 171B and fast-acting binary valves X1A and X1B between the pressure accumulators 2620 and 2610 and the control chamber 171B. The processor can control the pressure with a variety of control algorithms, including closed-loop proportional or proportional-integrator feedback control, which varies the valve duty cycle to achieve the desired pressure in the control volume 171B. In one embodiment, the processor controls the pressure in the control chamber with an on-off controller, often referred to as a bang-bang controller. The on-off controller monitors the pressure in the control volume 171B during the delivery stroke and opens the binary valve X1B (connecting the control volume 171B to the positive pressure reservoir 2620) when the pressure is below a first lower limit and closes the binary valve X1B when the pressure is above a second upper limit. During the delivery stroke, the on-off controller opens binary valve X1A (connecting control volume 171B to vacuum reservoir 2610) when the pressure exceeds a third limit and closes binary valve X1A when the pressure is below a fourth limit, where the fourth limit is less than the third limit and both the third and fourth limits are less than the first limit. A plot of pressure over time during the delivery stroke and subsequent FMS measurement is shown in FIG. 66. As membrane 15 moves across control chamber 171B, control chamber pressure 2300 oscillates between a first lower limit 2312 and a second upper limit 2310. The pressure stops oscillating between the limits when membrane 15 stops moving. Membrane 15 typically stops moving when it contacts one of the cassette's stadium steps 50 or when it contacts control chamber surface 171B. Membrane 15 can also stop moving if the outlet fluid line is blocked.

[0239] The automation computer 300 detects the end of stroke by evaluating the pressure signal. There are many possible algorithms for detecting the end of the pressure oscillation, which indicates the end of stroke (EOS). The algorithms and methods for detecting EOS in the section entitled "Detailed Description of the System and Method of Measuring Change Fluid Flow Rate" in U.S. Patent No. 6,520,747 and in the section describing filtering for detecting the end of stroke in U.S. Patent No. 8,292,594 are incorporated herein by reference.

[0240] In one example algorithm for detecting EOS, the AC300 evaluates the time between pressure crossings of the first and second limits during the supply stroke and the third and fourth limits during the intake stroke. An on-off controller opens and closes valves X1A and X1B in response to the pressure oscillating between the two limits as the control chamber volume changes during the intake or supply stroke. When the membrane 15 stops moving at the end of the stroke, the pressure change significantly decreases, so that the pressure no longer exceeds one or both limits. The AC300 can detect EOS by measuring the time between pressure crossings of alternate limits. If the time since the pressure crossed the last limit exceeds a predetermined threshold, the AC300 can declare EOS. The algorithm can further include an initial period during which the AC300 does not measure the time between limit crossings.

[0241] In another example algorithm, the AC300 evaluates the time derivative of the pressure signal. If the derivative remains below a minimum threshold for a minimum time, the AC300 can declare EOS. In a further example, the minimum threshold is the average of the absolute value of the average pressure derivative during the stroke. The algorithm calculates the slope (time derivative) of the curve fit for a set of data points, where the data points are taken from a moving window. The absolute value of each slope is then averaged over the stroke to calculate the absolute value of the average pressure derivative. In another example of an EOS algorithm, the AC300 may not have pressure data until after an initial delay. The AC300 ignores the initial pressure data to avoid false EOC detection due to irregular pressure traces that may occur during the early portion of the stroke. In another example, the AC300 declares EOS only if the second derivative of pressure in the later portion of the stroke remains below the threshold for a minimum time and after the wait period has passed.

[0242] The criteria for declaring EOS can be optimized for different pumping conditions. Optimized EOS detection conditions include the second pressure derivative threshold, the minimum time remaining below the second derivative threshold, the duration of the initial delay, and the length of the wait period. These EOS detection criteria, e.g., the inlet stroke from bags 20, 22, the delivery stroke to the patient, the inlet stroke from the patient, and the delivery stroke to bags 20, 22, can be optimized differently. Alternatively, each EOS detection criteria can be a function of the pumping pressure in control room 171B. [Occluded part] In one aspect of the invention, an occlusion for opening and closing one or more flexible lines can include a pair of opposing occlusion members, which can be formed as flexible elements such as flat plates (e.g., leaf springs) made from spring steel, with a force actuator configured to apply a force to one or both of the occlusion members to operate the occlusion. In some embodiments, the force actuator can include an expandable or expandable member disposed between the flexible elements. With the expandable member reduced in size, the flexible elements are in a flat or generally flat state, urging the pinch heads to pinch and engage one or more lines to close the lines. However, when the expandable member urges the flexible elements apart, the flexible elements bend and pull back the pinch heads, releasing the lines and allowing flow through the lines. In other embodiments, the occlusion member can be essentially rigid with respect to the level of force applied by the force actuator. In some embodiments, the force actuator is capable of applying a force to one or both opposing occlusion members, thereby increasing the distance between the occlusion members in at least a portion of the area where they face, thereby achieving opening and closing of the flexible tube.

[0243] FIG. 38 shows an exploded view and FIG. 39 shows a partial assembly view of an exemplary embodiment of an occlusion 147 that can be used to close or occlude the patient line 34 and the discharge line 28 and / or other lines (e.g., heater bag line 26, etc.) of the cycler 14 or set 12. The closure 147 includes an optional pinch head 161 (e.g., a generally flat blade-like element that contacts the tubing and pinches the tubing closed, forcing it against the door 141. In other embodiments, the pinch head function can be replaced by an extended edge on one or both of the closure members 165. The pinch head 161 includes a gasket 162, such as an O-ring or other member, that cooperates with the pinch head 161 to help resist the ingress of fluid (e.g., air or liquid) into the cycler 14 housing, for example, if there is a leak in one of the occluded lines. The bellows-shaped gasket 162 is attached to a pinch head guide 163 that is attached to the front panel of the cycler housing, through which the pinch head 161 passes (i.e., the panel is exposed by opening the door 141). The pinch head guide 163 allows the pinch head 161 to slide open and close. The pinch head 161 moves in and out of the pinch head guide 163 without binding and / or substantial resistance. The pivot shaft 164 attaches a pair of opposing closure members to the pinch head 161, each comprising a leaf spring 165 in the illustrated embodiment, each equipped with a hook-shaped pivot bearing (e.g., as found on a standard door hinge). That is, the openings in the pivot guide on the pinch head 161 and the openings formed by the hook-shaped bearings on the leaf spring 165 are aligned with one another, and the pivot shaft 164 is inserted into the openings, resulting in the pinch head 161 and leaf spring 165 being pivotally connected to one another. The leaf spring 165 can be made of any suitable material, such as steel, and can be positioned so that it is generally horizontal when unloaded. The opposite end of the leaf spring 165 is equipped with a similar hook-shaped bearing, which is pivotally connected to the linear adjuster 167 by the second pivot shaft 164.In this embodiment, the force actuator includes air bladders 166 positioned between the leaf springs 165, so that when a fluid (e.g., air under pressure) is introduced into the bladders, the bladders expand in the area between the pivots 164 and push the leaf springs 165 away from each other. The linear adjuster 167 is fixed to the cycler housing 82, while the pinch head 161 is allowed to float, its movement guided by the pinch head guide 163. The linear adjuster 167 includes a slotted hole at its lower end, allowing the entire assembly to be adjusted in position, thus allowing the pinch head to be properly positioned when the occlusion 147 is installed in the cycler 14. A turnbuckle 168 or other configuration can be used to assist in adjusting the position of the linear adjuster 167 relative to the housing 82. That is, pinch heads 161 generally must be properly positioned so that leaf springs 165 are positioned adjacent to one another and, with bladder 166 substantially evacuated or at atmospheric pressure, pinch heads 161 properly compress the patient and drainage lines to close off the flow of the tubing without cutting, kinking, or breaking the tubing. The slotted opening in linear adjuster 167 allows for precise positioning and securing of this occlusion 147 in place. An override release device, such as provided by release blades 169, can optionally be positioned between leaf springs 165 and rotated to push leaf springs 165 apart, thereby retracting pinch heads 161 into pinch head guides 163, as discussed in more detail below. Release blades 169 can be manually operated to disable occlusion 147, for example, in the event of a power loss, bladder 166 failure, or other circumstances.

[0244] Additional configurations and descriptions of certain components that may be useful in constructing certain embodiments of the occlusion are provided in U.S. Patent No. 6,302,653. The leaf springs 165 can be constructed from any material that has sufficient longitudinal stiffness (resistance to bending) to resiliently resist bending forces and provide sufficient restoring force in response to bending displacement to occlude the desired number of extruded tubes. In the illustrated embodiment, each leaf spring is essentially flat when unloaded and in the form of a sheet or plate. In alternative embodiments utilizing one or more flexible occlusion members (spring members), any occlusion member that has sufficient longitudinal stiffness (resistance to bending) to resiliently resist bending forces and provide sufficient restoring force in response to bending displacement to occlude the desired number of extruded tubes can be utilized. Potentially suitable spring members can have a wide variety of shapes, including, but not limited to, cylindrical, prismatic, trapezoidal, square, or rectangular rods or beams, I-beams, elliptical beams, and bowl-shaped surfaces, as will be apparent to those skilled in the art. Those skilled in the art can readily select appropriate materials and dimensions for the leaf spring 165 based on the present teachings and the requirements of a particular application.

[0245] FIG. 40 shows a top view of the occlusion section 147 with the bladders 166 deflated and the leaf springs 165 positioned adjacent to each other in a flat or nearly flat state. In this position, the pinch heads 161 are fully extended from the pinch head guides and the front panel of the cycler 14 (i.e., the panel inside the door 141), allowing them to occlude the patient and drainage lines. Meanwhile, FIG. 41 shows the bladders 166 in an inflated state, with the leaf springs 165 pushed away from each other, thereby retracting the pinch heads 161 into the pinch head guides 163. (Note that the linear adjusters 167 are fixed in position relative to the cycler housing 82 and, therefore, the front panel of the housing 82. The leaf springs 165 are moved away from each other, and the pinch heads 161 are positioned to move freely in and out of the pinch head guides 163, causing the pinch heads 161 to move rearward relative to the front panel.) This condition prevents pinch head 161 from occluding the patient and drainage lines, and occlusion portion 147 remains in place during normal operation of cycler 14. That is, as discussed above, various components of cycler 14 can be operated using air pressure / vacuum; for example, control surface 148 can operate under appropriate air pressure / vacuum drive to provide fluid pumping and valve operation to cassette 24. Thus, during normal operation of cycler 14, cycler 14 can generate sufficient air pressure to control system operation as well as inflate bladder 166, retract pinch head 161, and prevent occlusion of the patient and drainage lines. However, in the event of a system shutdown, malfunction, error, or other condition, air pressure to bladder 166 can be turned off, thereby deflating bladder 166, straightening leaf spring 165, and expanding pinch head 161 to occlude the lines. One possible advantage of the illustrated configuration is that the restoring force of the leaf spring 165 is balanced, so that the pinch head 161 is generally not constrained by the pinch head guide 163 as it moves relative to the pinch head guide 163.Additionally, the opposing forces of the leaf springs 165 tend to reduce the amount of asymmetric wear on the pivot shafts and bushings of the assembly. Also, once the leaf springs 165 are in a generally straight position, the leaf springs 165 can exert a force generally along the length of the pinch heads 161 that is several times greater than the force exerted by the bladders 166 on the leaf springs 165, thereby separating the leaf springs 165 from each other and retracting the pinch heads 161. Furthermore, with the leaf springs 165 in a flat or nearly flat state, the force required by the fluid in the collapsed tubes to overcome the compressive force exerted by the pinch heads 161 is applied to the leaf springs at their ends, reaching the relatively large force required when essentially parallel to the plane of the flattened leaf spring, thereby buckling the leaf spring by destroying its columnar stability. As a result, occlusion 147 can be very effective at occluding the line and reduce the chance of failure, while requiring a relatively small force to be applied by bladder 166 to retract pinch head 161. The dual leaf spring arrangement of the exemplary embodiment may have the added benefit of significantly increasing the compressive force provided by the pinch head for any given force required to bend the leaf spring and / or for any given size and thickness of the leaf spring.

[0246] In some situations, the force of the occlusion 147 on the line may be relatively large, making it difficult to open the door 141. That is, when the pinch head 161 contacts and occludes the line, the door 141 must counter the force of the occlusion 147, and in some cases, this may make it difficult or impossible to manually operate the latch that keeps the door 141 closed. Of course, if the cycler 14 is started and generating air pressure to operate, the occlusion bladder 166 can inflate, causing the occlusion pinch head 161 to retract. However, in some cases, such as a pump failure in the cycler 14, inflating the bladder 166 may be impossible or difficult. To allow the door to open, the occlusion 147 may be equipped with a manual release. In this exemplary embodiment, the occlusion 147 may be equipped with a release blade 169, as shown in FIGS. 38 and 39, which comprises a pair of blades pivotally mounted for rotational movement between leaf springs 165. When stopped, the release blade wings can be aligned with the spring, as shown in FIG. 39, allowing the closure to operate normally. However, if the leaf spring 165 is in a flattened position and the pinch head 161 needs to be manually retracted, the release blade 169 can be rotated, for example, by engaging a hex wrench or other tool with the release blade 169 and turning the release blade 169, causing the wings to push the leaf spring 165 apart. The hex wrench or other tool can be inserted into an opening in the housing 82 of the cycler 14 (e.g., an opening near the left handle recess of the cycler housing 82) and operated to disengage the closure 147, allowing the door 141 to open. [Pump supply volume measurement] In another aspect of the invention, cycler 14 is capable of determining the volume of fluid supplied to various lines of system 10 without the use of flow meters, weigh scales, or other direct measures of fluid volume or weight. For example, in one embodiment, the volume of fluid moved by a pump, such as the pump in cassette 24, can be determined based on pressure measurements of the gas used to drive the pump. In one embodiment, the volume determination can be made by isolating two chambers from each other, measuring the pressure in each of the two separated chambers, allowing the pressures in the two chambers to partially or substantially equalize (by fluidly connecting the two chambers), and measuring the pressure. Using the measured pressure, the known volume of one of the two chambers, and the assumption that equalization occurs adiabatically, the volume of the other chamber (e.g., the pump chamber) can be calculated. In one embodiment, the pressures measured after fluidly connecting the two chambers may not be substantially equal to each other (i.e., the pressures in the two chambers may not be completely equalized). However, as explained below, these substantially unequal pressures can be used to determine the volume of the pump control chamber.

[0247] For example, FIG. 42 shows a schematic diagram of pump chamber 181 of cassette 24, associated control components, and inflow / outflow paths. In this illustrated example, a fluid supply, which may include heater bag 22, heater bag line 26, and a fluid path through cassette 24, is shown providing a fluid input at upper opening 191 of the pump chamber. A fluid outlet, in this example, is shown receiving fluid from lower opening 187 of pump chamber 181 and may include, for example, the fluid path of cassette 24 and patient line 34. The fluid supply may include a valve (e.g., including valve port 192) that can be opened or closed to allow or block flow to or from pump chamber 181. Similarly, the fluid outlet may include a valve (e.g., including valve port 190) that can be opened or closed to allow or block flow to or from pump chamber 181. Of course, the fluid source can comprise any suitable configuration, such as one or more dialysate containers, a patient line, one or more flow paths within cassette 24, or other fluid sources; similarly, the fluid outlet can comprise any suitable configuration, such as a drain line, a heater bag and heater bag line, one or more flow paths within cassette 24, or other fluid outlets. Generally speaking, pump chamber 181 (i.e., to the left of membrane 14 in FIG. 42 ) is filled with an incompressible fluid, such as water or dialysate, during operation. However, air or other gas may be present in pump chamber 181 in some situations, such as during initial operation, during warm-up, or other situations as discussed below. Also, while aspects of the invention relating to pump volume and / or pressure sensing are described with respect to the pump configuration of cassette 24, it should be understood that aspects of the invention can be used with any suitable pump or fluid transfer system.

[0248] FIG. 42 also shows, to the right of the membrane 15 and control surface 148 (which are adjacent to one another), a control chamber 171, which may be formed as a void or other space in the mating block 170 associated with a pump control region 1482 of the control surface 148 relative to the pump chamber 181, as discussed above. An appropriate air pressure is introduced into the control chamber 171, thereby moving the membrane 15 / control region 1482 and achieving pumping of the liquid in the pump chamber 181. The control chamber 171 may communicate with a line L0, which branches into another line L1 and a first valve X1, which communicates with a pressure source (e.g., an air pressure source or a vacuum source). The pressure source may comprise a piston pump, whereby a piston moves within the chamber to control the pressure supplied to the control chamber 171, or may comprise a different type of pressure pump and / or tank, whereby an appropriate gas pressure is supplied to move the membrane 15 / control region 1482 and perform the pumping action. Line L0 then leads to a second valve X2, which communicates with another line L2 and a reference chamber (e.g., a space suitably configured to perform measurements as described below). The reference chamber then communicates with line L3, which has valve X3 leading to a vent or other reference pressure (e.g., an atmospheric pressure source or other reference pressure source). Each of valves X1, X2, and X3 can be independently controlled. Pressure sensors can be positioned to measure pressures associated with the control and reference chambers, e.g., one sensor in the control chamber 171 and another in the reference chamber. These pressure sensors can be positioned and operated to detect pressure in any suitable manner. The pressure sensors can be in communication with a control system 16 for the cycler 14 or other suitable processor that determines the volume delivered by a pump or other feature.

[0249] As discussed above, the valves and other components of the pump mechanism shown in FIG. 42 can be controlled to measure the pressure in the pump chamber 181, the liquid supply, and / or the liquid outlet, and / or to measure the volume of liquid delivered from the pump chamber 181 to the liquid supply or liquid outlet. With respect to volumetric measurements, one technique used to determine the volume of fluid delivered from the pump chamber 181 is to compare the relative pressure in the control chamber 171 to the pressure in a reference chamber for two different pump states. By comparing the relative pressures, a change in the volume of the control chamber 171 can be determined, which corresponds to a change in the volume of the pump chamber 181 and is reflected in the volume delivered from and received by the pump chamber 181. For example, after the pressure in the control chamber 171 is reduced during a pump chamber induction cycle (e.g., by applying negative pressure from a pressure source through open valve X1), thereby drawing the membrane 15 and pump control region 1482 into contact with at least a portion of the control chamber wall (or to another suitable position of membrane 15 / region 1482), valve X1 is closed to isolate the control chamber from the pressure source, and valve X2 is closed, thereby isolating the reference chamber from the control chamber 171. Valve X3 can be opened to vent the reference chamber to atmospheric pressure and then closed to isolate the reference chamber. With valve X1 closed and the pressures in the control and reference chambers measured, valve X2 is then opened to initiate pressure equalization in the control and reference chambers. The initial pressures in the reference and control chambers, along with the known volume of the reference chamber and the pressure measured after equalization has begun (but not necessarily completed), may be used to determine the volume of the control chamber. This process can be repeated at the end of the pump delivery cycle when the sheet 15 / control region 1482 is forced into contact with the spacer element 50 of the pump chamber 181. By comparing the control chamber volume at the end of the delivery cycle with the volume at the end of the induction cycle, the volume of liquid delivered from the pump can be determined.

[0250] Conceptually, the pressure equalization process (e.g., upon opening valve X2) can be viewed as occurring adiabatically, i.e., without heat transfer occurring between the air in the control and reference chambers and their surroundings. The conceptual idea is that when valve X2 closes, a virtual piston is initially positioned at valve X2, and when valve X2 opens, the virtual piston moves in line L0 or L2 to equalize the pressures in the control and reference chambers. Because (a) the pressure equalization process occurs relatively quickly, (b) the air in the control and reference chambers has approximately the same elemental concentrations, and (c) the temperatures are similar, the assumption that pressure equalization occurs adiabatically can introduce only small errors in volume measurements. Also, in one embodiment, pressures obtained after equalization has begun can be measured before substantial equalization occurs, further shortening the time between the initial and final pressure measurements used to determine pump chamber volume. Additionally, errors can be reduced by using materials with low thermal conductivity for, for example, the membrane 15 / control surface 148, cassette 24, control chamber 171, lines, reference chamber, etc., thereby reducing heat conduction.

[0251] Assuming that an adiabatic system exists between the state where valve X2 is closed and the state where valve X2 is open and pressure equalizes, the following holds: PVγ=constant (1) where P is pressure, V is volume, and γ is equal to a constant (e.g., approximately 1.4 if the gas is diatomic such as air). Thus, the following equation can be written to relate the pressure and volume in the control and reference chambers before and after opening valve X2 and pressure equalization occurs:

[0252] PrVrγ+PdVdγ=constant=PfVfγ ...(2)Here, Pr is the pressure in the reference chamber and lines L2 and L3 before opening valve X2, Vr is the volume of the reference chamber and lines L2 and L3 before opening valve X2, Pd is the pressure in the control chamber and lines L0 and L1 before opening valve X2, Vd is the volume of the control chamber and lines L0 and L1 before opening valve X2, Pf is the equalized pressure in the reference chamber and control chamber after opening valve X2, and Vf is the volume of the entire system including the control chamber, reference chamber, and lines L0, L1, L2, and L3 (i.e., Vf=Vd+Vr). Since Pr, Vr, Pd, Pf, and γ are known and Vf = Vr + Vd, this equation can be used to solve for Vd. (Although reference is made herein, including in the claims, to the use of "measured pressure" in determining volume values ​​and the like, it should be understood that such measured pressure values ​​need not necessarily be in any particular form, such as in psi units.) Alternatively, "measured pressure" or "determined pressure" can include any value representative of pressure, such as potential, resistance, multi-bit digital value, etc. For example, a pressure transducer used to measure pressure in a pump control chamber can output an analog potential, resistance, or other representation representative of the pressure in the pump control chamber. The raw output from the transducer can also be used as the measured pressure and / or some modified form of output, such as a digital value generated using the analog output from the transducer, psi or other value generated based on the transducer output, etc. The same is true for other values, such as determined volume, but not necessarily in a particular form, such as cubic centimeters. Alternatively, the determined volume can include any value that is representative of volume and can be used to generate an actual volume in cubic centimeters, for example.

[0253] In an embodiment of a fluid management system (FMS) technique for determining the volume delivered by the pump, pressure equalization upon opening valve X2 is assumed to occur in an adiabatic system. Thus, equation (3) below provides the relationship between the volumes of the reference chamber system before and after pressure equalization:

[0254] Vrf = Vri (Pf / Patm) - (1 / γ) ... (3) where Vrf is the final (post-equalization) volume of the reference chamber system, including the volume of the reference chamber, the volume of lines L2 and L3, and the volume adjustment caused by the movement of the "piston" that can move to the left or right of valve X2 after opening; Vri is the initial (pre-equalization) volume of the reference chamber and lines L2 and L3 when the "piston" is located at valve X2; Pf is the final equalization pressure after valve X2 opens; and Patm is the initial pressure of the reference chamber (atmospheric pressure in this example) before valve X2 opens. Similarly, equation (4) gives the relationship between the volumes of the control chamber system before and after pressure equalization.

[0255] Vdf=Vdi(Pf / Pdi)-(1 / γ) ...(4) Here, Vdf is the final volume of the control chamber system including the volume of the control chamber, the volume of lines L0 and L1, and the volume adjustment caused by the movement of the "piston" that can move to the left or right of valve X2 after it is opened, Vdi is the initial volume of the control chamber and lines L0 and L1 when the "piston" is positioned in valve X2, Pf is the final pressure after valve X2 opens, and Pdi is the initial pressure in the control chamber before valve X2 opens.

[0256] The volumes of the reference and control chamber systems change by the same absolute amount after valve X2 opens and pressure equalizes, but with different signs, as shown in equation (5) (e.g., because the volume change is caused by the movement of the "piston" to the left or right when valve X2 opens).

[0257] ΔVr=(-l)ΔVd …(5) (Note that this change in volume of the reference and control chambers is due only to the movement of the virtual piston. The reference and control chambers do not actually change volume during the equalization process under normal conditions.) Also, using the relationship from equation (3), the volume change of the reference chamber system is given by the following equation:

[0258] ΔVr=Vrf-Vri=Vri(-1+(Pf / Patm)-(1 / γ)) …(6) Similarly, using equation (4), the volume change of the control room system is given by:

[0259] ΔVd=Vdf-Vdi=Vdi(-1+(Pf / Pdi)-(1 / γ)) …(7) With Vri known and Pf and Patm measured or known, ΔVr can be calculated, which is assumed to be equal to (-)ΔVd according to equation (5). Therefore, Vdi (the volume of the control chamber system before pressure equalization with the reference chamber) can be calculated using equation (7). In this embodiment, Vdi represents the volume of the control chamber and lines L0 and L1, where L0 and L1 are fixed and known quantities. Subtracting L0 and L1 from Vdi yields the control chamber volume alone. Using equation (7) above, for example, the volume change of the control chamber can be determined both before (Vdi1) and after (Vdi2) pump action (e.g., at the end of the inlet cycle and the end of the outlet cycle), thus providing a measure of the volume of fluid delivered by (or taken into) the pump. For example, if Vdi1 is the volume of the control chamber at the end of the fill stroke and Vdi2 is the volume of the control chamber at the end of the subsequent delivery stroke, the volume of fluid delivered by the pump can be estimated by subtracting Vdi1 from Vdi2. Because this measurement is based on pressure, the volume determination can be made for almost any position of the membrane 15 / pump control region 1482 within the pump chamber 181, regardless of whether the pumping stroke is complete or partial. However, measurements made at the end of the fill and delivery strokes can be achieved with little or no effect on pump operation and / or flow rate.

[0260] One aspect of the present invention involves techniques for identifying pressure measurements used to determine the volume of a control chamber and / or for other purposes. For example, pressure sensors can be used to detect pressure in the control chamber and the reference chamber, but the detected pressure values ​​may change depending on the opening and closing of valves, the introduction of pressure into the control chamber, venting the reference chamber to atmospheric pressure or other reference pressure, etc. Also, in one embodiment, because an adiabatic system is assumed to exist between the control chamber and the reference chamber before and after pressure equalization, identifying appropriate pressure values ​​measured closely in time can help reduce errors (e.g., a short elapsed time between pressure measurements can reduce the amount of heat exchanged in the system). Thus, the measured pressure values ​​may need to be carefully selected to help ensure that the appropriate pressure is used to determine the volume delivered by a pump or the like.

[0261] For illustrative purposes, FIG. 43 shows a plot of exemplary pressure values ​​for the control and reference chambers from a time before valve X2 is opened until valve X2 is opened to allow the pressures in the two chambers to equalize. In this exemplary embodiment, the pressure in the control chamber is higher than the pressure in the reference chamber before equalization; however, it should be understood that the pressure in the control chamber may be lower than the pressure in the reference chamber before equalization in some configurations, such as during and / or at the end of the fill stroke. Also, while the plot in FIG. 43 shows a horizontal line marking the equalization pressure, it should be understood that this line is shown for clarity only. The equalization pressure is generally unknown before valve X2 is opened. In this embodiment, pressure sensors detect pressure at a frequency of approximately 2000 Hz for both the control and reference chambers, although other suitable sampling rates can be used. Before valve X2 is opened, the pressures in the control and reference chambers are substantially constant, and no air or other fluids are introduced into the two chambers. Thus, valves X1 and X3 are generally closed before valve X2 is opened. Additionally, valves leading to the pump chamber, such as valve ports 190 and 192, can be closed to prevent the effects of pressure changes in the pump chamber, liquid supply, or liquid outlet.

[0262] First, the measured pressure data is processed to identify initial pressures (i.e., Pd and Pr) for the control and reference chambers. In one exemplary embodiment, the initial pressures are identified based on an analysis of a 10-point sliding window used on the measured pressure data. This analysis involves generating a best-fit line to the data (or data set) within each window, using, for example, a least-squares method, and determining the slope of the best-fit line. For example, each time a new pressure is measured for the control or reference chamber, a least-squares fit line can be determined for a data set including the most recent measurement and nine previous pressure measurements. This process can be repeated for several sets of pressure data, and a determination can be made when the slope of the least-squares fit line first becomes negative (or non-zero) and continues to grow more negative (or deviate from zero slope) for subsequent data sets. The point at which the least-squares fit line has an appropriate increasing non-zero slope can be used to identify the initial pressure of the two chambers (i.e., the point before valve X2 opens).

[0263] In one embodiment, the initial pressure values ​​for the reference and control chambers can be determined to be at the end of five consecutive data sets, where the slope of the line of best fit for those data sets increases from the first data set to the fifth data set, with the slope of the line of best fit for the first data set being the first to become non-zero (i.e., the slope of the line of best fit for data sets preceding the first data set is zero or not sufficiently non-zero). For example, the pressure sensor can sample every half millisecond (or other sampling rate), beginning sampling before valve X2 opens. Each time a pressure measurement is made, cycler 14 can take the most recent measurement along with the previous nine measurements to generate a line of best fit for the ten data points in the set. When the next pressure measurement is taken (e.g., half a millisecond later), cycler 14 can take the most recent measurement along with the nine previous measurements to again generate a line of best fit for the ten points in the set. This process can be repeated, with the cycler 14 determining when the slope of the best fit line for a set of ten data points first becomes non-zero (or when it is appropriately sloped), e.g., determining that the slope of the best fit line for five subsequent sets of ten data points increases with each subsequent data set. To identify the specific pressure measurement to use, one technique is to select the third measurement in the fifth data set (i.e., the fifth data set in which the best fit line is found to increase with a consistent slope and in which the first measurement is the earliest pressure measurement in time) to be used as the initial pressure (i.e., Pd or Pr) for the control or reference chamber. This selection is made using an empirical method (e.g., plotting the pressure measurements and then selecting the point that best represents when the pressure began the equalization process). Of course, other techniques can be used to select the appropriate initial pressure.

[0264] In one exemplary embodiment, confirmation can be made that t...

Claims

1. In a heating system for a peritoneal dialysis machine, a pumping device configured to pump dialysis fluid to and from the heater bag; an electric heater configurable to operate with an AC line voltage in the range of 100-120 volts or an AC line voltage in the range of 200-240 volts; a heater controller configured to control a temperature of the dialysis fluid using the electric heater; and and a universal power supply configured to convert line voltage to one or more DC voltages to power the pumping device and the heater controller, and to configure the electric heater to operate at a voltage in the range of 100 to 120 volts or in the range of 200 to 240 volts based on a measured current flow through the electric heater.

2. 2. The heating system of claim 1, wherein the electric heater comprises two heating elements, ends of each heating element connected to a common point, the universal power supply comprises one or more electrical switches connecting the heating elements to a line voltage in a configuration switchable between a parallel or a series configuration, and the universal power supply comprises circuitry for measuring a current through the electric heater, and a power supply controller arranged to control the electrical switches to configure the heating elements based on the measured current.

3. 3. The heating system of claim 2, wherein the one or more electrical switches comprise a heater select relay that connects the heating elements in parallel when the power controller controls the heater select relay to be energized.

4. 4. The heating system of claim 3, wherein said heating elements are connected in series when said heater select relay is in a de-energized state.

5. The heating system of claim 1 , wherein the heater controller controls a solid state relay coupled to the electric heater to control power delivery to the electric heater via pulse width modulation.

6. 3. The heating system of claim 2, wherein the heater controller controls two solid state relays, each connected to a different heating element, to control power supply to the heating elements by pulse width modulation.

7. 7. The heating system of claim 6, wherein the solid state relay is connected to an active line of an AC line voltage source or a neutral line of the AC line voltage source.

8. 7. The heating system of claim 6, wherein one of the two solid-state relays is connected to an active line of an AC line voltage source and the other is connected to a neutral line of the AC line voltage source.

9. The heating system of claim 2 , wherein the heater controller and the power supply controller comprise a single heater circuit controller.

10. 3. The heating system of claim 2, further comprising a safety relay for disconnecting the electric heater from the AC line voltage based on a signal from a safety controller.

11. The heating system of claim 10 , wherein the heater controller, the power controller, and the safety controller comprise a single heater circuit controller.

12. 3. The heating system of claim 2, wherein the power controller is arranged to measure current through the electric heaters in a series configuration and to control one or more electric switches to change the configuration of the heating elements if the measured current is below a predetermined value.

13. 13. The heating system of claim 12, wherein the predetermined value of the measured current corresponds to a current resulting from an AC line voltage of 200-240 volts applied to the electric heater in series.

14. 7. The heating system of claim 6, wherein if the measured current is less than a predetermined value, the heater controller commands a solid state relay to 100% duty cycle and the one or more electrical switches place the heating elements in series, and the power supply controller measures the current through the electric heater and commands the one or more electrical switches to place the heating elements in parallel.

15. 1. A method of operating a heating system for a peritoneal dialysis machine for configuring a heating element of an electric heater for a peritoneal dialysis machine, the electric heater comprising two heating elements, each of the heating elements having an end connected to a common point, the method comprising: a controller initially configuring the heating elements in a series configuration; the controller connecting the electric heater to line voltage; the controller measuring a current flow through the electric heater; the controller determining from the measured current flow whether the line voltage is in the range of 100-120 volts or in the range of 200-240 volts; providing information about the determined line voltage to a user of the peritoneal dialysis machine by the controller; The method finally comprises the step of the controller receiving a verification signal from a user before configuring the heating elements in either a series or parallel configuration.

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