Automated peritoneal dialysis system having disposable cassette having valve seat

Abstract

To provide a preferable automated peritoneal dialysis system.SOLUTION: A peritoneal dialysis system (10) comprises a cycler (20) and a disposable medical fluid cassette (130). The cycler includes a pump actuator (60), a patient line valve actuator (34e), at least one supply line valve actuator (34b, 34c), and a drain line valve actuator (34a). The disposable medical fluid cassette includes: a pumping portion (126) configured to operate with the pump actuator (60); a patient line valve seat (132e) configured to operate with the patient line valve actuator (34e); a rigid body (138) defining a common well (146); at least one supply line valve seat (132b, 132c) located in the common well and configured to operate with at least one supply line valve actuator; and a drain line valve seat (132a) located in the common well and configured to operate with the drain line valve actuator.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] (Priority Claim) This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 185,050, filed May 6, 2021, entitled "Automated Peritoneal Dialysis Assembly," the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to medical fluid treatment, and more particularly to dialysate treatment. [Background technology]

[0003] Due to various causes, a person's renal system may fail. Renal failure results in several physiological disturbances. It is no longer possible to balance water and minerals or to excrete the daily metabolic load. Toxic end products of metabolism such as urea, creatinine, and uric acid may accumulate in the patient's blood and tissues.

[0004] Reduced kidney function, especially kidney failure, is treated by dialysis. Dialysis removes waste, toxins and excess water from the body that normally functioning kidneys would otherwise remove. Dialysis treatment for replacement of kidney function is important for many people because the treatment is life-saving.

[0005] One type of renal failure treatment is hemodialysis ("HD"), which generally uses diffusion to remove waste products from a patient's blood. A diffusion gradient occurs across a semi-permeable dialyzer between the blood and an electrolyte solution called the dialysate or dialysate, causing diffusion.

[0006] Hemofiltration ("HF") is an alternative renal replacement therapy that relies on the convective transport of toxins from the patient's blood. HF is achieved by adding replacement or substitution fluid to the extracorporeal circuit during treatment. Substitution fluid and fluids accumulated by the patient between treatments are ultrafiltered over the course of the HF treatment, providing a convective transport mechanism that is particularly beneficial in removing middle and large molecules.

[0007] Hemodiafiltration ("HDF") is a procedure that combines convective and diffusive clearance. HDF uses dialysate flowing through a dialyzer, similar to standard hemodialysis, to provide diffusive clearance. In addition, a replacement solution is delivered directly to the extracorporeal circuit to provide convective clearance.

[0008] Most HD, HF, and HDF treatments are performed in centers. There is a trend today toward home hemodialysis ("HHD") because HHD can be performed daily, providing therapeutic benefits over in-center hemodialysis treatments that are typically performed two or three times a week. Studies have shown that more frequent treatments remove more toxins and waste products and cause less interdialytic fluid overload than patients undergoing less frequent, but perhaps longer, treatments. Patients undergoing more frequent treatments do not experience as many down cycles (fluid and toxin fluctuations) as in-center patients who build up two or three days' worth of toxins before treatment. In certain regions, the nearest dialysis center may be many miles away from the patient's home, causing door-to-door treatment times to consume a large portion of the day. Treatments at facilities closer to the patient's home may also consume a large portion of the patient's day. HHD can be performed overnight or during the day while the patient relaxes, works, or is otherwise productive.

[0009] Another type of kidney failure treatment is peritoneal dialysis ("PD"), which infuses a dialysis solution, also called dialysate, into a patient's peritoneal cavity through a catheter. The dialysate is in contact with a peritoneal membrane in the patient's peritoneal cavity. Waste, toxins and excess water enter the dialysate from the patient's bloodstream through capillaries in the peritoneal membrane due to diffusion and osmosis (i.e., an osmotic gradient that occurs across the membrane). An osmotic agent in the PD fluid provides the osmotic gradient. Spent or exhausted dialysate is drained from the patient, removing the waste, toxins and excess water from the patient. This cycle is repeated, for example, multiple times.

[0010] There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis ("CAPD"), automated peritoneal dialysis ("APD"), tidal flow dialysis, and continuous flow peritoneal dialysis ("CFPD"). CAPD is a manual dialysis procedure, in which the patient manually connects an implanted catheter to a drain to allow used or spent dialysate to drain from the peritoneal cavity. The patient then switches the fluid communication so that the patient catheter is in communication with a bag of fresh dialysate to infuse fresh dialysate through the catheter and into the patient. The patient disconnects the catheter from the fresh dialysate bag, allowing the dialysate to dwell in the peritoneal cavity, where waste, toxins, and excess water transfer occurs. After a dwell period, the patient repeats the manual dialysis procedure, for example, four times a day. Manual peritoneal dialysis requires a significant amount of time and effort from the patient, leaving ample room for improvement.

[0011] Automated peritoneal dialysis ("APD") is similar to CAPD in that the dialysis treatment includes drain, fill and dwell cycles. However, APD devices typically perform the cycles automatically while the patient sleeps. APD devices relieve the patient from having to manually perform treatment cycles and from having to make supplemental substances during the day. APD devices fluidly connect to an implanted catheter, a source or bag of fresh dialysate, and a fluid drain. APD devices pump fresh dialysate from the dialysate source through the catheter to the patient's peritoneal cavity. APD devices also allow the dialysate to dwell in a chamber where waste, toxins and excess water transfer can occur. The source may contain multiple liters of dialysate including several solution bags.

[0012] APD machines pump used dialysate, or dialysis waste, from the patient's peritoneal cavity through a catheter to a drain. As with the manual process, several drain, fill and dwell cycles occur during dialysis. A "last fill" may occur at the end of an APD treatment. The last fill fluid may remain in the patient's peritoneal cavity until the start of the next treatment, or it may be manually emptied at some point during the day.

[0013] Known APD systems include a device or cycler that accepts and actuates a pumping cassette, which has a rigid portion and a soft portion that is deformable to perform the pumping and valving. Sealing the fluid disposable cassette with the pneumatic path via a gasket to provide actuation has proven to be a potential field issue that can delay treatment start times and affect the user experience. Pneumatic cassette systems also generate acoustic noise that can be a source of customer dissatisfaction.

[0014] For each of the above reasons, there is a need for improved APD devices. Summary of the Invention [Means for solving the problem]

[0015] This disclosure describes a streamlined automated peritoneal dialysis ("APD") system and associated cycler that uses a peristaltic pump and a disposable set that organizes the tubing and performs a number of functions discussed below. The cycler of the system in one embodiment includes a peristaltic pump actuator that can pump in two directions. Flow in either direction passes through a disposable cassette that is part of the overall disposable set.

[0016] The disposable cassettes are mounted within the housing of the cycler, in one embodiment mounted perpendicular to the working surface of the housing and then enclosed between the working surface and a hinged door of the housing. A user interface that communicates with the control unit is provided next to the housing door, whereby the patient or user typically interacts with one surface of the device to input commands, receive data, and load the disposable cassettes.

[0017] The system in one embodiment also includes a bag shelf enclosure that serves multiple purposes. The bag shelf enclosure is sized so that the cycler can be stored inside the enclosure when the cycler is not in use. The bag shelf enclosure is also sized so that the bag shelf enclosure can be set on top of the cycler when the cycler is in use. The bag shelf holds multiple containers or bags, such as multiple supply containers and one or more drain containers. In one example, multiple supply containers are placed in the bag shelf enclosure during a procedure, and a drain container and a final fill container are placed outside and on top of the enclosure. The bag shelf enclosure can include color-coded markers provided at locations for loading containers or bags with lines extending through apertures into the cycler, the apertures having similar color-coded markers. The matching color-coded markers make it easy for the patient or caregiver to identify which bag and line belong to which location on the bag shelf enclosure.

[0018] It is conceivable that the supply container or bag may later be used as a drain container or bag to reduce overall disposable costs. For example, assume that the patient is full of effluent at the start of treatment. That effluent is first drained from the patient and delivered to an empty drain container. A first patient fill is then delivered from the first supply container to the patient and after a specified dwell period is delivered to the same drain container or a different drain container depending on the size of the drain container. The drain container is used to receive the effluent until the first supply container is empty, after which the first supply container receives the effluent after a dwell period using PD fluid delivered from the second supply container. The first supply container is used to receive the effluent, possibly over multiple patient fills, dwells, and drains, until the second supply container is empty. At that point, the patient may receive a final fill of a different formulation of peritoneal dialysis fluid, which will remain in the patient until the next night's treatment, or perhaps until a daytime exchange.

[0019] At the end of the treatment, the multiple containers or bags are filled with effluent. To prevent the patient or caregiver from having to transport the drain bag to a house drain, e.g., a toilet, sink or bathtub, the cycler's control unit is programmed to prompt the user to disconnect the patient line from the patient's transfer set and carry the distal end of the patient line to the house drain. As used herein, "house drain" should be understood to mean any type of drain provided to any type of building or residence, such as a house, apartment, work building, hospital, clinic, public or private facility, etc. If necessary, a reusable extension line may be connected to the distal end of the patient line to reach the house drain. The patient or caregiver then presses a drain button on the user interface, at which time the cycler operates the peristaltic pump actuator in a direction to draw the spent dialysate or effluent from each of the drain containers (one or more of which may be previous supply containers) and pump the spent dialysate through the patient line (and extension line, if necessary) to the house drain. The cycler detects when each drain container is empty (e.g., via a weight scale and / or pressure sensor, described in more detail below) and automatically switches a valve actuator, such as a pinch valve actuator, between the drain containers in sequence until each drain container is empty. The above sequence is repeated for any remaining fresh dialysate in the main supply container or last fill container. It should be appreciated that multiple drain containers (one or more of which may be previous supply containers) may be drained in parallel or simultaneously, e.g., to save time. In this manner, once the patient disconnects the patient line and presses the drain button, the patient is free to begin their day.

[0020] As described above, in one embodiment, the cycler uses peristaltic pumping. A peristaltic pump actuator under the control of a control unit is located on the working surface of the cycler. The disposable cassette includes a peristaltic pump tube that a user guides over the peristaltic pump actuator when loading the cassette. During operation, the peristaltic pump actuator compresses the peristaltic pump tube against a track at multiple points. The track's operative proximity to the peristaltic pump actuator makes loading the tube difficult. Thus, the cycler includes a movable track that translates out of the way of the peristaltic pump actuator via a linkage when a patient or caregiver opens the cycler door to load the cassette. After the cassette is loaded, closing the cycler door translates the movable track via a linkage to an operative position directly adjacent the peristaltic pump tube. In an alternative embodiment, a motor and lead screw assembly, or a linear actuator (e.g., a linear stepper motor) is provided to automatically translate the track out of the way of the peristaltic pump actuator when the patient or caregiver opens the cycler door to load the cassette, and to automatically translate the track to an operational position when the door is closed. In a further alternative embodiment, a motor and lead screw assembly, or a linear actuator (e.g., a linear stepper motor) is provided, but the patient or caregiver instead presses one or more buttons on a user interface to translate the track out of the way or to an operational position.

[0021] In an embodiment, the track is attached to a block or member that is translatable across the working surface toward and away from the peristaltic pump actuator. In addition to the translational movement of the member (and track), the movable track can also rotate about a pivot axis provided at one end of the track, the pivot axis being attached to the translatable member. The other end of the track is spring loaded via a spring, e.g., a compression spring, trapped between the track end and the member. The spring urges the track about the pivot axis into a desired operating position about the peristaltic pump tube when the member is translated toward the peristaltic pump actuator. The pivoting track may also provide a damping effect to absorb or tolerate variations due to tubing tolerances and aid in noise reduction.

[0022] As mentioned above, the cycler in one embodiment uses pinch valve actuators, where the disposable cassette is provided with valve seats that receive the pinch valve actuators to occlude or close the fluid paths provided by the disposable cassette, where the cassette is sealed and covered with a flexible sheet, e.g., flexible plastic, where the pinch valve actuators are pressed into their respective valve seats to close their respective fluid paths, and the pinch valve actuators retract to open their respective fluid paths.

[0023] The pinch valves are each driven by a linear actuator, which may be any suitable type of linear actuator, such as a linear stepper motor, that provides the required amount of travel (e.g., up to 10 mm) and the required amount of pressurized cassette seat closing force (e.g., 30 to 60 Newtons ("N") or less). The linear actuator drives the valve plunger back and forth to press the cassette seat against the cassette valve seat, allowing the seat to be removed from the cassette valve seat. The valve plunger in one embodiment includes a proximal end effector that couples to the linear actuator and a distal end effector that slidably couples to the proximal end effector. A spring, such as a wave or compression spring, may be provided on the plunger and positioned to bias the distal end effector outwardly against the proximal end effector. The variable distance provided by the spring allows the pinch valve to initially contact the cassette seat with a smaller closing force that steadily increases as the spring is compressed. In an embodiment, a flexible membrane, such as a silicone membrane, is secured to the actuation surface over the end of the distal end effector such that the flexible membrane contacts the cassette sheet. When the spring is fully compressed, the cassette sheet experiences the full force of the linear actuator and the spring. Thus, the spring provides a force buffer that helps protect the flexible membrane over multiple procedures and protects the cassette sheet over the course of a single procedure. The spring may help with variations due to disposable cassette tolerances and cassette loading, and may further allow for smaller or less expensive linear actuators.

[0024] As described above, the disposable cassette provides multiple valve seats, which may include a patient line valve seat, first and second supply line valve seats, a final fill line valve seat, and a drain line valve seat. In one embodiment, the patient line valve seat is fluidly separated from the first peristaltic tube port by an in-line fluid heating path, e.g., a serpentine path. When the disposable cassette is loaded for operation, the in-line fluid heating path is adjacent to a heater, such as a resistive plate heater.

[0025] In one embodiment, the first and second supply line valve seats, the final fill line valve seat, and the drain line valve seat are each disposed in a common well in fluid communication with the second peristaltic tube port. In this manner, fresh dialysate can be pumped in a first direction from either the supply container for the first and second supply line valve seats or the final fill line valve seat, through the common well and the in-line fluid heating pathway, where the fresh dialysate is heated, and out the patient line valve seat to the patient. Spent dialysate or effluent can be pumped in a second direction from the patient through the patient line valve seat and the in-line fluid heating pathway, where the spent dialysate is not heated, to the common well, and out the drain line valve seat to the drain container.

[0026] Any of the valve seats described herein may include a tapered seal surface surrounded by a plurality of displacement ribs, each of which extends from a rigid wall of the disposable cassette, at least some of which are spaced apart to prevent or mitigate unwanted blockage of the tapered seal surface by the flexible sheet and allow fresh or used dialysate flow therethrough. The displacement ribs may be completely separate from each other or may extend from a common cylindrical base. The displacement ribs may be separate from the tapered seal surface or may extend from an outer edge of the tapered seal surface. The displacement ribs prevent ingress of the flexible sheet into the tapered seal surface. The displacement ribs may guide the respective pinch valve plunger toward the center of the valve seat while providing a certain amount of resiliency or play between the pinch valve plunger and the valve seat. In an embodiment, the tapered seal surface tapers to form a funnel shape that leads to an opening that allows fresh or used dialysate to flow into or out of the valve seat. In embodiments, the opening extends through a port disposed on the other side of the rigid body of the disposable cassette, the port sealably receiving (attaching) a tube or line, such as a patient line, a supply line or a drain line, etc. The tapered sealing surface may also include or define one or more circular sealing rings that compress the flexible sheet when the flexible sheet is closed by the pinch valve.

[0027] In an embodiment, a first or patient pressure sensing pod is disposed within the disposable cassette directly adjacent to the patient line valve seat. The patient pressure sensing pod when the disposable cassette is loaded is adjacent to a first or patient pressure sensor that outputs to a cycler control unit. The patient pressure sensor output can be used to control the positive and negative pumping pressures experienced by the patient within safe pressure limits. A second or pumping pressure sensing pod is disposed within the disposable cassette between the common well and the second peristaltic tube port. The pumping pressure sensing pod when the disposable cassette is loaded is adjacent to a second or pumping pressure sensor that outputs to a cycler control unit. The pumping pressure sensor output can be used to detect blockages in the supply and drain lines and / or supply empty conditions.

[0028] The disposable cassette may also include one or more areas adjacent a thermocouple or other temperature sensor that outputs to a control unit when loaded for operation. The temperature sensing area may be located, for example, at the end of the in-line fluid heating pathway directly adjacent to the patient pressure sensing pod, so that the outlet temperature of the fresh dialysate to the patient may be monitored and controlled, for example, via a proportional, integral, derivative ("PID") routine executed by the control unit using feedback from the temperature sensor to a desired temperature, such as body temperature or 37°C. A second temperature sensor may be optionally positioned to detect the temperature at the inlet to the in-line fluid heating pathway, which may also provide useful information for the PID routine.

[0029] It is contemplated that a pressure sensor may be mounted on the working surface of the cycler such that when a disposable cassette is loaded for operation, the cassette sheet, which may be polyvinyl chloride ("PVC"), is contacted and placed under tension by the pressure sensor to generate a baseline force that is measured by the pressure sensor. Fresh or used dialysate pressure further displaces (or attempts to displace) the cassette sheet, thereby increasing or decreasing the fluid force acting on the pressure sensor relative to the baseline force. The force difference caused by the positive or negative fluid pressure is correlated with actual fluid pressure values ​​by the control unit, which may be used for pressure control, displayed by a user interface, and / or stored for delivery to a remote computer for evaluation.

[0030] Pretensioning the cassette sheet by the pressure sensor results in a pressure sensing regime with high sensitivity and resolution, but it can be prone to temperature sensitivity. It is therefore conceivable to compensate for temperature, where the voltage output (or current output) from the pressure sensor is modified by adding a component that is a function of the measured temperature (e.g., using the thermocouple described above) multiplied by an empirically determined temperature scaling factor to form a compensated voltage output, which is then converted or correlated to a compensated positive or negative pressure.

[0031] As mentioned above, pre-tensioning the cassette sheet by the pressure sensor results in a pressure sensing regime with high sensitivity and resolution, but may also be prone to mechanical creep sensitivity. To combat creep sensitivity, in one embodiment, the control unit is programmed to pre-condition the cassette sheet prior to a procedure, for example during set-up, thereby eliminating much of the pressure signal fluctuation due to creep before the pressure measurement becomes an issue. To do so, the control unit after the disposable cassette is primed causes all pinch valves to close and then activates the peristaltic pump actuator to pressurize the interior of the cassette, including the pressure pod, to stretch the cassette sheet. The control unit may be programmed to cause the pump actuator to cyclically oscillate the cassette fluid pressure up and down multiple times over a specified period of time, with the upper pressure limit being, for example, 100% to 150% of the maximum operating pressure set for the procedure. Pre-conditioning the cassette sheet helps to make the uncompensated pressure reading more accurate, while temperature compensation helps to make the final pressure reading more accurate.

[0032] The disclosed systems and cyclers, in one embodiment, use a gravimetric scale with multiple load cells to monitor the amount of fresh dialysate delivered to the patient, the amount of spent dialysate removed from the patient, and allow the control unit to calculate therefrom the amount of ultrafiltration ("UF") removed from the patient. The gravimetric scale and load cells are advantageous for several reasons. First, the gravimetric scale is relatively accurate compared to other volume measurement techniques. Second, the gravimetric scale reduces pump costs because the pump actuator can be a relatively simple peristaltic pump actuator and the disposable portion of the pump can be a simple peristaltic pump tubing.

[0033] One drawback of using load cells is calibration. Load cells can read inaccurately over time and therefore need to be recalibrated. The cycler and associated systems of the present invention provide a weigh scale with multiple load cells and an on-board structure and methodology for calibrating the weigh scale. In one embodiment, the weigh scale includes a weight plate located on top of the cycler that supports the weight of the bag shelf enclosure and the solution and drain containers and each of the associated fresh and used dialysate. The weight plate and each weighed item on the weight plate are supported by multiple, for example, four, load cells that collectively measure the total mass (bag shelf enclosure, containers and fluid) placed on the weight plate. The on-board calibration structure in one embodiment includes a fifth load cell and a linear actuator (which may be the same type used for pinch valves) located between the fifth load cell and the weight plate.

[0034] The linear actuator includes an actuation output shaft secured to the weight plate such that the linear actuator can apply a pulling or downward force to the weight plate. In one implementation, the pulling force is applied to the center of mass of the lower surface of the weight plate. An additional calibration load cell measures the total force applied, while the four working load cells each measure a portion or quarter of the total force. If each of the working load cells is operating properly, the sum of their outputs should equal the total force measured by the calibration load cells. In one example, assume a pulling force of 1000 Newtons ("N") is applied by the linear actuator. The calibration load cell then outputs 1000N, and the equidistant working load cells 102a-102d should each read 250N and combine to sum to 1000N.

[0035] Because the calibration load cells are used infrequently, the calibration algorithm is applied assuming that the output of the calibration load cells is more accurate than the aggregate output of the working load cells used throughout each procedure. Thus, during calibration, if there is a discrepancy between what the calibration load cells read and the aggregate output of the working load cells, the control unit using the calibration algorithm will scale or offset the aggregate output of the working load cells to match the aggregate output of the calibration load cells. In the above example, assume that the working load cells actually collectively read 995N instead of 1000N. Thus, the reading of the working load cells is 0.5% lower. The control unit is thereby configured to correct the aggregate output of the working load cells during the procedure by a calibration factor of 1000 / 995 or 1.005.

[0036] Because the calibration load cell is used infrequently, the calibration algorithm assumes that its output is more accurate than the aggregate output of the working load cells used throughout each procedure. Thus, during calibration, if there is a discrepancy between what the calibration load cell reads and the aggregate output of the working load cells, the control unit using the calibration algorithm will scale or offset the aggregate output of the working load cells to match the aggregate output of the calibration load cells. In the above example, assume that the working load cells actually collectively read 605 Newtons instead of 600 Newtons. Thus, the working load cells only sense 395 Newtons of the 400 Newtons applied. Thus, the working load cell reading is 1.3% lower. The cycler's control unit is thereby configured to correct the aggregate output of the working sensors during the procedure by a calibration factor of 400 / 395 or 1.01.

[0037] The load cell calibration routine or algorithm is run on some desired basis, for example, before the start of each treatment. It should also be appreciated that since many of the weight values ​​monitored and collected during treatment are weight differences, errors in the aggregate output of the operational load cells will tend to cancel out, assuming the errors do not change over the course of the treatment. For example, the mass associated with a patient fill volume of 2 liters is monitored and controlled by the aggregate output of the operational load cells, which records the drop in mass over the course of the patient fill. The volume and mass associated with the patient drain may be preset in the control unit, for example, multiplying the fill volume by a factor such as 1.3 to account for the patient UF removed in the drain volume. The volume and mass associated with the patient drain may alternatively be left open ended and instead controlled by sensing a characteristic rise in negative pressure by the pumping pressure sensing pod and associated pressure sensor, which indicates that the patient is essentially fully drained and that further draining may be uncomfortable for the patient. In either case, the operational load cells will sense an increase in weight over the course of the patient drain, which should tend to cancel out the errors in the operational load cells.

[0038] In a first aspect, which in light of the disclosure herein is not intended to limit the disclosure in any way but may be combined with any other aspect or portion thereof, a peritoneal dialysis system includes a cycler including a pump actuator; a disposable set including a pumping unit operable with the pump actuator, a patient line arranged in fluid communication with the pumping unit, and a drain container arranged in fluid communication with the pumping unit; and a control unit configured to: (i) cause the pump actuator to perform a peritoneal dialysis treatment in which fresh dialysate is pumped through the patient line to a patient and used dialysate is pumped from the patient to the drain container, and (ii) at the end of the treatment, operate the pumping unit to pump the used dialysate from the drain container through the patient line to a house drain.

[0039] In a second aspect of the present disclosure which may be combined with any other aspect or a portion thereof, the pump actuator is a peristaltic pump actuator and the pumping portion of the disposable set includes a peristaltic pump tube.

[0040] In a third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the peritoneal dialysis system includes an extension line configured to be connected to a patient line to reach a house drain as needed.

[0041] In a fourth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the extension line is reusable.

[0042] In a fifth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the peritoneal dialysis system includes a user interface in communication with the control unit, the user interface configured to prompt the patient at the end of treatment to disconnect the patient line and move the patient line toward a house drain.

[0043] In a sixth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the peritoneal dialysis system includes a user interface in communication with the control unit, the user interface configured to provide or enable a drain button at the end of treatment to initiate pumping of spent dialysis solution from the drain container to a house drain via the patient line.

[0044] In a seventh aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the user interface is further configured to request confirmation that the drain line is in fluid communication with the house drain before providing or enabling the drain button.

[0045] In an eighth embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the cycler includes a patient valve actuator that operates with a patient valve seat provided by the disposable set and a drain valve actuator that operates with a drain valve seat provided by the disposable set, and the control unit is configured to cause the patient valve actuator and the drain valve actuator to enable flow through the patient valve seat and the drain valve seat and to pump spent dialysate from the drain container through the patient line to a house drain.

[0046] In a ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, at least one of the patient valve actuator or the drain valve actuator is a pinch valve actuator.

[0047] In a tenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a peritoneal dialysis system includes a supply container arranged in fluid communication with a pumping portion of a disposable set, the supply container being used during a peritoneal dialysis treatment to pump fresh dialysis fluid through a patient line to a patient.

[0048] In an eleventh embodiment of the present disclosure that may be combined with any other embodiment or portion thereof, the supply container is used later during a peritoneal dialysis treatment to receive used dialysis fluid from the patient.

[0049] In a twelfth embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the cycler includes a sensor in operative communication with a control unit, and the control unit is configured to use an output from the sensor to determine whether one of the drain container or the supply container subsequently used as the drain container is empty or substantially empty after pumping the spent dialysate to the house drain, and then switch to the other of the drain container or the supply container subsequently used as the drain container for pumping the spent dialysate to the house drain.

[0050] In a thirteenth aspect of the present disclosure that may be combined with any other aspect or a portion thereof, the sensor is a weight sensor or a pressure sensor.

[0051] In a fourteenth aspect of the present disclosure, which may be combined with any other aspect or a portion thereof, the control unit is further configured to cause the pump actuator to activate the pumping section at the end of treatment to pump remaining fresh dialysis fluid from the supply container through the patient line to the house drain.

[0052] In a fifteenth embodiment of the present disclosure, which may be combined with any other embodiment or a portion thereof, the drain container is a first drain container and includes a second drain container arranged to be fluidly connected to the pumping section of the disposable set, and the cycler includes a sensor in operative communication with the control unit, and the control unit is configured to use an output from the sensor to determine whether the first drain container is empty or substantially empty after pumping the spent dialysate to the house drain, and then switch to the second drain container for pumping the spent dialysate to the house drain.

[0053] In a sixteenth aspect of the present disclosure which may be combined with any other aspect or a portion thereof, the sensor of the fifteenth aspect is a weight sensor or a pressure sensor.

[0054] In a seventeenth aspect of the present disclosure which may be combined with any other aspect or a portion thereof, the drain container is a first drain container and includes a second drain container arranged to be in fluid communication with the pumping section of the disposable set, and the control unit is configured to drain the first and second drain containers simultaneously.

[0055] In an eighteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a peritoneal dialysis system includes a cycler including a pump actuator; a disposable set including a pumping unit operable with the pump actuator, a patient line arranged in fluid communication with the pumping unit, and a drain line arranged in fluid communication with the pumping unit; and a control unit configured to cause the pump actuator to (i) perform a peritoneal dialysis treatment in which fresh dialysate is pumped through the patient line to a patient and used dialysate is pumped from the patient through the drain line, and (ii) at the end of the treatment, operate the pumping unit to pump the used dialysate through the drain line and the patient line to a house drain.

[0056] In a nineteenth embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the drain line is in fluid communication with a drain container, which is initially provided as a drain container or supply container filled with fresh dialysis fluid.

[0057] In a twentieth embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the patient line and the drain line are separated by a disposable cassette of the disposable set, and at the end of treatment, the spent dialysate is pumped through the drain line, through the disposable cassette, through the patient line, and to the house drain.

[0058] In a twenty-first embodiment of the present disclosure, which may be combined with any other embodiment or a portion thereof, the disposable cassette includes a pressure sensing pod arranged to enable detection of a pressure change indicating that a drain container in fluid communication with the drain line is empty, and thereafter, the control unit switches to drain spent dialysis fluid from a different source to the house drain at the end of treatment.

[0059] In a twenty-second embodiment that may be combined with any other embodiment or portion thereof of the present disclosure, the cycler includes a weighing scale, and a drain container in fluid communication with the drain line is arranged to be weighed by the weighing scale, and an output from the weighing scale indicating that the drain container is empty is used by the control unit to switch to draining spent dialysis fluid from a different source to a house drain at the end of treatment.

[0060] In a twenty-third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a peritoneal dialysis system includes a cycler including a pump actuator; a disposable set including a pumping unit operable with the pump actuator, a patient line arranged in fluid communication with the pumping unit, and a drain container arranged in fluid communication with the pumping unit; and a control unit configured to cause the pump actuator to (i) perform a peritoneal dialysis treatment in which fresh dialysate is pumped through the patient line to a patient and used dialysate is pumped from the patient to the drain container, and (ii) at the end of the treatment, operate the pumping unit to pump the used dialysate from the drain container through the patient line to a desired destination.

[0061] In a twenty-fourth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the desired destination includes a house drain or another container disposed in fluid communication with the pumping portion.

[0062] In a twenty-fifth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, pumping the used dialysis fluid from the drain container through the patient line during (ii) includes operating the pumping unit in a first direction to at least partially fill the patient line with the used dialysis fluid, and then operating the pumping unit in a second direction to remove the used dialysis fluid from the patient line to a desired destination.

[0063] In a twenty-sixth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a disposable medical fluid cassette includes a pumping section, a patient line valve seat arranged in fluid communication with the pumping section, a rigid body defining a common well, the common well in fluid communication with the pumping section, at least one supply line valve seat arranged within the common well, and a drain line valve seat arranged within the common well.

[0064] In a twenty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the patient line valve seat is provided by a rigid body.

[0065] In a twenty-eighth embodiment of the present disclosure that may be combined with any other embodiment or portion thereof, the pumping portion includes a peristaltic pump tube attached to a rigid body.

[0066] In a twenty-ninth aspect of the present disclosure that may be combined with any other aspect or a portion thereof, the pumping portion includes a pump chamber defined by a rigid body.

[0067] In a thirtieth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the rigid body defines an in-line fluid heating path disposed between the patient line valve seat and the pumping portion.

[0068] In a thirty-first aspect of the present disclosure that may be combined with any other aspect or portion thereof, a disposable medical fluid cassette includes a temperature sensing region disposed between a patient line valve seat and an in-line fluid heating pathway.

[0069] In a thirty-second aspect of the present disclosure that may be combined with any other aspect or portion thereof, the in-line fluid heating path is configured such that fresh dialysis fluid flows upward during priming to remove air through the patient line valve seat.

[0070] In a thirty-third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a disposable medical fluid cassette includes at least one of a pumping pressure sensing pod disposed between a drain line valve seat and a first end of the in-line fluid heating pathway, or a patient pressure sensing pod disposed between a patient line valve seat and a second end of the in-line fluid heating pathway.

[0071] In a thirty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a disposable medical fluid cassette includes at least one of a patient line in fluid communication with a patient line valve seat, at least one supply line in fluid communication with at least one supply line valve seat, or a drain line in fluid communication with a drain line valve seat.

[0072] In a thirty-fifth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the disposable medical fluid cassette includes at least one of a pumping pressure sensing pod positioned adjacent to the patient line valve seat or a pumping pressure sensing pod positioned adjacent to the common well.

[0073] In a thirty-sixth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a disposable medical fluid cassette includes a flexible sheet sealed to a rigid body, the flexible sheet being bent to open and close at least one supply line valve seat and a drain line valve seat.

[0074] In a thirty-seventh embodiment of the present disclosure that may be combined with any other embodiment or portion thereof, the rigid body includes a rigid wall defining a common well, and the flexible sheet is sealed to the rigid wall to surround the common well.

[0075] In a thirty-eighth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, at least one of the patient line valve seat, the at least one supply line valve seat, or the drain line valve seat includes a tapered sealing surface surrounded by a plurality of displacement ribs, at least some of the displacement ribs being spaced to mitigate ingress of the flexible sheet into the tapered sealing surface.

[0076] In a thirty-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the common well includes a slope configured to direct air in the common well toward the drain line valve seat.

[0077] In a fortieth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the drain line valve seat is positioned relative to at least one supply line valve seat in a common well such that the drain line valve seat is positioned higher than the at least one supply line valve seat to direct air toward the drain line valve seat when the disposable medical fluid cassette is loaded for operation.

[0078] In a forty-first aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a peritoneal dialysis system includes a cycler including a pump actuator, a patient line valve actuator, at least one supply line valve actuator, and a drain line valve actuator; a pumping unit configured to operate with the pump actuator, a patient line valve seat configured to operate with the patient line valve actuator, and a disposable medical fluid cassette including a rigid body defining a common well, at least one supply line valve seat disposed in the common well and configured to operate with the at least one supply line valve actuator, and a drain line valve seat disposed in the common well and configured to operate with the drain line valve actuator.

[0079] In a forty-second embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the cycler is configured to perform a patient drain in which used dialysate enters a common well, followed by a patient fill in which fresh dialysate enters the common well.

[0080] In a forty-third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, during patient drain, a drain line valve actuator is actuated to allow used dialysate to exit the common well through the drain line valve seat, and during patient fill, one of the at least one supply line valve actuator is actuated to allow fresh dialysate to enter the common well through one of the at least one supply line valve seats.

[0081] In a forty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, during patient drain and patient fill, a patient line valve actuator is actuated to allow used dialysis fluid and fresh dialysis fluid to flow through the patient line valve seat, respectively.

[0082] In a forty-fifth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a valve seat for a disposable medical fluid cassette includes a rigid wall, a tapered sealing surface extending from the rigid wall, the tapered sealing surface surrounding an opening formed in the rigid wall, and a plurality of displacement ribs extending from the rigid wall or from an outer edge of the tapered sealing surface to surround the tapered sealing surface, the displacement ribs being spaced to mitigate unwanted blockage of the tapered sealing surface.

[0083] In a forty-sixth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the displacement ribs are separate from one another or extend from a common cylindrical base.

[0084] In a forty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the tapered sealing surface is cylindrical and the displacement ribs collectively form a cylindrical shape that surrounds the tapered sealing surface.

[0085] In a forty-eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the tapered sealing surface forms a funnel shape that leads to the opening.

[0086] In a forty-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the opening extends through a port disposed on the opposite side of the rigid wall from the tapered sealing surface and the displacement rib.

[0087] In a fiftieth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the tapered sealing surface includes at least one circular sealing ring for compressing against a mating sealing member.

[0088] In a fifty-first aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a pinch valve includes a linear actuator, a proximal end effector coupled to the linear actuator, a distal end effector slidably engaged to the proximal end effector, and a spring positioned and arranged to bias the distal end effector outward relative to the proximal end effector.

[0089] In a fifty-second aspect of the present disclosure that may be combined with any other aspect or portion thereof, the linear actuator includes a linear stepping motor.

[0090] In a fifty-third aspect of the present disclosure which may be combined with any other aspect or portion thereof, the proximal end effector and the distal end effector form a valve plunger.

[0091] In a fifty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the proximal end effector includes a larger diameter portion and a smaller diameter portion, and the distal end effector includes a cylindrical opening that slidably receives the smaller diameter portion of the proximal end effector.

[0092] In a fifty-fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spring is disposed between a step that transitions between the larger diameter portion and the smaller diameter portion and the distal end effector.

[0093] In a fifty-sixth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the spring is constrained by a smaller diameter portion of the proximal end effector.

[0094] In a fifty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, an outer diameter of the distal end effector is at least substantially equal to an outer diameter of a larger diameter portion of the proximal end effector.

[0095] In a fifty-eighth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the spring is a wave spring or a compression spring.

[0096] In a fifty-ninth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, one of the proximal end effector or the distal end effector defines at least one groove, and the other of the proximal end effector or the distal end effector includes at least one spring arm that mechanically fits into the at least one groove.

[0097] In a sixtieth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, at least one groove is sized to provide a travel length of the distal end effector relative to the proximal end effector that is greater than or equal to the uncompressed length of the spring.

[0098] In a sixty-first aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a dialysis device includes an actuating surface onto which a fluid transporting member is loaded to perform a dialysis treatment; a hole formed in the actuating surface; and a pinch valve including a linear actuator, a proximal end effector coupled to the linear actuator, a distal end effector slidably engaged to the proximal end effector, and a spring positioned and arranged to bias the distal end effector outwardly relative to the proximal end effector, wherein the pinch valve is mounted within the device such that the distal end effector extends through the hole to block a portion of the fluid transporting member.

[0099] In a sixty-second embodiment of the present disclosure that may be combined with any other embodiment or portion thereof, the hole is covered by a flexible membrane, and the distal end effector bends the flexible membrane to block a portion of the fluid transport member.

[0100] In a sixty-third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the pinch valve is mounted within the device such that the spring is compressed before a portion of the fluid conveying member experiences a full occlusion force applied by the linear actuator.

[0101] In a sixty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the hole is a first hole, the pinch valve is a first pinch valve, the actuation surface defines a second hole adjacent the first hole, and includes a second pinch valve mounted within the device, and a distal end effector of the second pinch valve extends through the second hole to block a second portion of the fluid conveying member.

[0102] In a sixty-fifth embodiment of the present disclosure which may be combined with any other embodiment or portion thereof, the dialysis machine includes a control unit programmed to sequence the first and second pinch valves according to a preprogrammed sequence.

[0103] In a sixty-sixth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a dialysis device operable with a disposable set having a peristaltic pump tubing includes an actuating surface for receiving the disposable set, a peristaltic pump actuator extending from the actuating surface, the peristaltic pump actuator operable with the peristaltic pump tubing, a member translatable along the actuating surface, a track pivotally connected to the member at a first end via a pivot axis, and a spring biased to urge a second end of the track outwardly from the member about the pivot axis.

[0104] In a sixty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the dialysis device includes a stopper arranged to limit a distance that the spring can push the second end of the track outwardly from the member.

[0105] In a sixty-eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spring is disposed around the stopper.

[0106] In a sixty-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the stopper is connected to the member and moves with the member.

[0107] In a seventieth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the stopper extends through an aperture or opening formed in the second end of the member and includes a head larger than at least one dimension of the aperture or opening, and a spring is biased to press the second end of the member against the head.

[0108] In a seventy-first aspect of the present disclosure which may be combined with any other aspect or portion thereof, the spring is a compression or extension spring.

[0109] In a seventy-second aspect of the present disclosure that may be combined with any other aspect or portion thereof, the member includes a base that defines an arc having a radius that at least substantially matches a radius of the orbit.

[0110] In a seventy-third aspect of the present disclosure which may be combined with any other aspect or portion thereof, the dialysis device includes a stopper arranged to stop the rotation of the orbit caused by the spring when the radius of the orbit at least substantially reaches the radius of the arc.

[0111] In a seventy-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the actuation surface defines a linear rail, the member translates along the linear rail, and an underside of the member includes a rail receiver sized to operate with the linear rail.

[0112] In a seventy-fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the straight rail and the rail receiver are configured such that the straight rail slidably holds the member against the actuation surface.

[0113] In a seventy-sixth aspect of the present disclosure which may be combined with any other aspect or portion thereof, the member defines at least one slot for enabling the member to be slidably attached to the actuation surface.

[0114] In a seventy-seventh aspect of the present disclosure which may be combined with any other aspect or portion thereof, the dialysis machine includes a door configured to open and close relative to an actuation surface, and further includes a linkage positioned and arranged to translate the track away from the peristaltic pump actuator when the door is open and to translate the track to an operable position relative to the peristaltic pump actuator when the door is closed.

[0115] In a seventy-eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the dialysis machine includes a door configured to open and close relative to an actuation surface, and further includes an electric assembly configured to translate the track away from the peristaltic pump actuator and to translate the track to an operable position relative to the peristaltic pump actuator at different times.

[0116] In a seventy-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the motorized mechanism includes a motor operable by a lead screw or a linear actuator.

[0117] In an eightieth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the motorized mechanism is configured to (i) automatically translate the track away from the peristaltic pump actuator when the door is opened and automatically translate the track to an operable position relative to the peristaltic pump actuator when the door is closed, or (ii) translate the track away from the peristaltic pump actuator and / or translate the track to an operable position relative to the peristaltic pump actuator at different times in response to at least one user interface input.

[0118] In an eighty-first aspect of the present disclosure that may be combined with any other aspect or portion thereof, a dialysis machine operable with a disposable set having a peristaltic pump tubing includes an actuation surface for receiving the disposable set, a peristaltic pump actuator extending from the actuation surface, the peristaltic pump actuator operable with the peristaltic pump tubing, a track translatable along the actuation surface, a door openable and closable relative to the actuation surface, and a linkage or motorized mechanism configured to (i) translate a screw groove away from the peristaltic pump actuator to move the peristaltic pump tubing to a position against the peristaltic pump actuator, and (ii) translate the screw groove to a position operable relative to the peristaltic pump tubing.

[0119] In an 82nd aspect of the present disclosure which may be combined with any other aspect or portion thereof, there is provided a linkage mechanism, the linkage mechanism configured and arranged such that when a door is opened, (i) is performed, and when the door is closed, (ii) is performed.

[0120] In an 83rd aspect of the present disclosure which may be combined with other aspects or portions thereof, there is provided an electric mechanism configured and arranged such that when a door is opened, (i) is automatically performed, and when the door is closed, (ii) is automatically performed.

[0121] In an 84th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, an electric mechanism is provided, wherein at least one of (i) or (ii) is executed in response to a user interface input.

[0122] In an eighty-fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the motorized mechanism includes a motor operable by a lead screw or a linear actuator.

[0123] In an 86th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a medical fluid system includes a medical fluid pump actuator, a medical fluid transfer set having a flexible sheet, a temperature sensor positioned and arranged to detect a temperature of medical fluid flowing through the medical fluid transfer set, a pressure sensor positioned and arranged to contact the flexible sheet when the medical fluid transfer set is loaded for operation by the medical fluid pump actuator, and a control unit configured to (i) precondition the flexible sheet for operation with the pressure sensor by causing the medical fluid pump actuator to apply pressure to the flexible sheet, and (ii) use output from the temperature sensor in a compensation algorithm that modifies the output from the pressure sensor.

[0124] In an eighty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the medical fluid pump actuator is a peristaltic pump actuator.

[0125] In an 88th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the pressure sensor is positioned such that the flexible sheet is placed under tension through contact with the pressure sensor when the medical fluid transfer set is loaded for operation by the medical fluid pump actuator.

[0126] In an eighty-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the pressure sensor is operable with a pressure pod portion of the flexible sheet.

[0127] In a ninetieth embodiment of the present disclosure which may be combined with any other embodiment or portion thereof, the pressure applied during (i) is a fluid pressure.

[0128] In a 91st embodiment of the present disclosure which may be combined with any other embodiment or portion thereof, the pressure applied during (i) is a cyclic up and down pressure.

[0129] In a 92nd embodiment of the present disclosure which may be combined with any other embodiment or portion thereof, the pressure applied during (i) is 100% to 150% of the maximum operating pressure supplied during the procedure.

[0130] In a 93rd aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the medical fluid system includes a plurality of valves operable by a medical fluid transfer set, and the control unit causes the plurality of valves to be closed during (i).

[0131] In a 94th aspect of the present disclosure, which may be combined with any other aspect or part thereof, the algorithm comprises: V T =V 0 +gT, V 0 is the output from the pressure sensor, and V T is the corrected pressure output, g is the temperature scaling factor, and T is the sensed temperature.

[0132] In a 95th aspect of the present disclosure, which can be combined with other aspects or portions thereof, the control unit is configured to update the temperature compensation algorithm (i) each time the output from the pressure sensor is read by the control unit, or (ii) periodically.

[0133] In a 96th aspect of the present disclosure, which can be combined with other aspects or portions thereof, the control unit is configured to use the corrected output from the pressure sensor (ii) for at least one of (a) controlling the medical fluid pump actuator to pump within the patient's pressure limits, (b) determining a line occlusion condition, or (c) determining a container empty condition.

[0134] In a 97th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a medical fluid system includes a medical fluid pump actuator, a medical fluid transfer set having a flexible sheet, a pressure sensor arranged such that when the medical fluid transfer set is loaded for operation by the medical fluid pump actuator, the flexible sheet is placed under tension through contact with the pressure sensor, and a control unit configured to precondition the flexible sheet for operation by the pressure sensor by applying pressure to the flexible sheet by the medical fluid pump actuator.

[0135] In a 98th embodiment of the present disclosure that may be combined with any other embodiment or portion thereof, the pressure applied during preconditioning is a fluid pressure.

[0136] In a 99th embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the pressure applied during preconditioning is cyclic up and down pressure.

[0137] In a hundredth embodiment of the present disclosure, which may be combined with any other embodiment or portion thereof, the pressure applied during preconditioning is 100% to 150% of the maximum operating pressure supplied during treatment.

[0138] In a hundred and first aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a medical fluid system includes a plurality of valves operable with a medical fluid transfer set, and a control unit causes the plurality of valves to be closed during preconditioning.

[0139] In a hundred-second aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a medical fluid system includes a medical fluid pump actuator, a medical fluid transfer set having a flexible sheet, a temperature sensor positioned and arranged to detect a temperature of medical fluid flowing through the medical fluid transfer set, a pressure sensor arranged such that the flexible sheet is placed under tension through contact with the pressure sensor when the medical fluid transfer set is loaded for operation by the medical fluid pump actuator, and a control unit configured to use output from the temperature sensor in a compensation algorithm that modifies the output from the pressure sensor.

[0140] In a hundred and third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to update a temperature compensation algorithm (i) each time an output from the pressure sensor is read by the control unit, or (ii) periodically.

[0141] In a hundred-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to use a corrected output from the pressure sensor for at least one of (i) controlling the medical fluid pump actuator to pump within the patient's pressure limits, (ii) determining a line occlusion condition, or (iii) determining a container empty condition.

[0142] In a hundred and fifth aspect of the present disclosure, which may be combined with any other aspect or a portion thereof, a dialysis device operable with a disposable set having at least one container includes a pump actuator operable to pump dialysis fluid to and / or from at least one container, a weight plate arranged to support the at least one container, a plurality of operating load cells arranged to support the weight plate, a linear actuator arranged to apply a force to the weight plate, a calibration load cell arranged to measure the force applied by the linear actuator, and a control unit in operative communication with the operating load cell, the linear actuator, and the calibration load cell, wherein the control unit is configured to cause the linear actuator to apply a force to the weight plate, compare the resulting outputs from the operating load cell and the calibration load cell, and determine a calibration coefficient from the comparison to offset future outputs from the operating load cell.

[0143] In a hundred and sixth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the operating load cells are positioned to be at least substantially equidistant from the center of mass of the weight plate.

[0144] In a hundred and seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the calibration load cell is positioned so as to be at least substantially at the center of mass of the weight plate.

[0145] In a hundred eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the linear actuator includes a motor and a lead screw, or a linear stepping motor.

[0146] In a hundred and ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the linear actuator is disposed between the calibration load cell and the weight plate.

[0147] In a 110th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to sum a resulting output from the operating load cell for comparison with a resulting output from the calibration load cell.

[0148] In a 111th aspect of the present disclosure that may be combined with any other aspect or portion thereof, a calibration factor for offsetting future outputs from the operating load cells is applied to the sum of future outputs from the operating load cells.

[0149] In a twelfth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the calibration coefficient includes a resultant output from the calibration load cell divided by the sum of the resultant outputs from the operational load cells.

[0150] In a 113th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the linear actuator is in mechanical communication with the weight plate, and the control unit is configured to cause the linear actuator to apply a pulling force to the weight plate.

[0151] In a 114th aspect of the present disclosure that may be combined with any other aspect or a portion thereof, the control unit is configured to cause the linear actuator to apply a force to the weight plate before the container is placed on the weight plate.

[0152] In a 115th aspect of the present disclosure, which may be combined with any other aspect or a portion thereof, the control unit is configured to cause the linear actuator to apply a force to the weight plate during processing while the container is supported by the weight plate.

[0153] In a 116th aspect of the present disclosure, which may be combined with any other aspect or a portion thereof, the control unit is in operative communication with a pump actuator, and at least an operating duration of the pump actuator is controlled using an offset output from an operating load cell.

[0154] In a 117th aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit is configured to not cause the linear actuator to supply force for the duration of the operation.

[0155] In a 118th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to use two or more offset outputs from the operating load cell to determine mass or volumetric flow during treatment.

[0156] In a 119th aspect of the present disclosure, which may be combined with any other aspect or a portion thereof, a dialysis system comprises a disposable set including a pumping unit and at least one container, and a dialysis machine, the dialysis machine including a pump actuator operable with the pumping unit to pump dialysis fluid to and / or from at least one supply container, a weight plate arranged to support the at least one container, a plurality of operating load cells arranged to support the weight plate, a linear actuator arranged to apply a force to the weight plate, a calibration load cell arranged to measure the force applied by the linear actuator, and a control unit operatively communicating with the operating load cell, the linear actuator, and the calibration load cell, the control unit configured to cause the linear actuator to apply a force to the weight plate, compare resulting outputs from the operating load cell and the calibration load cell, and determine a calibration coefficient from the comparison to offset future outputs from the operating load cell.

[0157] In a 120th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to sum a resulting output from the operating load cell for comparison with a resulting output from the calibration load cell.

[0158] In a 121st aspect of the present disclosure, which may be combined with any other aspect or portion thereof, a calibration coefficient for offsetting the resulting output from the operating load cells is applied to the sum of the resulting outputs from the operating load cells.

[0159] In a 122nd aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the at least one container includes at least one supply container, the pump actuator is operable with the pumping unit to pump fresh dialysis from the at least one supply container, and the control unit is configured to determine the amount of fresh dialysis solution to be delivered using at least two offset outputs from the operating load cell.

[0160] In a 123rd aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the at least one container includes at least one drain container, the pump actuator is operable with the pumping section to pump used dialysis to the at least one drain container, and the control unit is configured to determine the amount of used dialysis solution to be delivered using at least two offset outputs from the operating load cell.

[0161] In a 124th aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit is configured to use at least two offset outputs from the operating load cell to determine the amount of fresh dialysis fluid delivered to the patient or the amount of used dialysis fluid removed from the patient.

[0162] In a 125th aspect of the present disclosure, any of the features, functions, and alternatives described in connection with any one or more of Figures 1 to 13 may be combined with any of the features, functions, and alternatives described in connection with any other of Figures 1 to 13 and / or any of the aspects enumerated herein.

[0163] It is therefore an advantage of the present disclosure to provide an accurate APD system that uses a relatively simple and cost-effective peristaltic pump.

[0164] Another advantage of the present disclosure is that it provides an APD system that eliminates certain sealing problems present in known APD systems.

[0165] A further advantage of the present disclosure is that it provides an APD pump drive system that eliminates the bulky pneumatic equipment associated with certain APD systems.

[0166] Yet another advantage of the present disclosure is providing an APD pump drive system that reduces noise as compared to pneumatic systems.

[0167] Yet another advantage of the present disclosure is to provide an APD system that manages peritoneal dialysis fluid flow to be within safe and comfortable patient pressure limits.

[0168] Yet another advantage of the present disclosure is providing an APD system with a simplified disposable set.

[0169] A further advantage of the present disclosure is to provide an APD system with accurate pressure and weight sensing.

[0170] Moreover, an advantage of the present disclosure is to provide an APD system that simplifies removal of spent dialysate to accommodate a drain for a patient.

[0171] Additional features and advantages will be described in and become apparent from the following detailed description and drawings. The features and advantages described herein are not all-inclusive, and in particular many additional features and advantages will be apparent to those skilled in the art in view of the drawings and description. Also, any particular embodiment need not have all of the advantages listed herein, and it is expressly contemplated to separately claim each advantageous embodiment. Furthermore, it should be noted that the language used in this specification has been selected primarily for ease of reading and description purposes, and is not intended to limit the scope of the inventive subject matter. The present specification also provides, for example, the following: (Item 1) A disposable medical fluid cassette (130), comprising: A pumping section (126); a patient line valve seat (132e) disposed in fluid communication with the pumping portion (126); a rigid body (138) defining a common well (146), said common well (146) in fluid communication with said pumping portion (126); at least one supply line valve seat (132b, 132c) disposed within the common well (146); a drain line valve seat (132a) disposed within the common well (146); A disposable medical fluid cassette (130). (Item 2) 2. The disposable medical fluid cassette (130) of item 1, wherein the patient line valve seat (132e) is provided by the rigid body (138). (Item 3) 2. The disposable medical fluid cassette (130) of item 1, wherein the pumping portion (126) includes a peristaltic pump tube attached to the rigid body (138). (Item 4) 2. The disposable medical fluid cassette (130) of claim 1, wherein the pumping portion (126) includes a pump chamber defined by the rigid body (138). (Item 5) 2. The disposable medical fluid cassette (130) of item 1, wherein the rigid body (138) defines an in-line fluid heating path (144) disposed between the patient line valve seat (132e) and the pumping section (126). (Item 6) 6. The disposable medical fluid cassette (130) of claim 5, comprising a temperature sensing region (148) disposed between the patient line valve seat (132e) and the in-line fluid heating pathway (144). (Item 7) 6. The disposable medical fluid cassette (130) of item 5, wherein the in-line fluid heating path (144) is configured to allow fresh dialysis fluid to flow upward during priming to remove air through the patient line valve seat (132e). (Item 8) 6. The disposable medical fluid cassette (130) of item 5, comprising at least one of a pumping pressure sensing pod (150b) disposed between the drain line valve seat (132a) and a first end of the in-line fluid heating path (144) or a patient pressure sensing pod (150a) disposed between the patient line valve seat (132e) and a second end of the in-line fluid heating path (144). (Item 9) 2. The disposable medical fluid cassette (130) of item 1, comprising at least one of a patient line in fluid communication with the patient line valve seat (132e), at least one supply line in fluid communication with the at least one supply line valve seat (132b, 132c), or a drain line in fluid communication with the drain line valve seat (132a). (Item 10) 2. The disposable medical fluid cassette (130) of item 1, comprising at least one of a pumping pressure sensing pod (150a) positioned adjacent to the patient line valve seat (132e) or a pumping pressure sensing pod (150b) positioned adjacent to the common well (146). (Item 11) 2. The disposable medical fluid cassette (130) of claim 1, comprising a flexible sheet (136) sealed to the rigid body (138), the flexible sheet (136) being bendable to open and close the at least one supply line valve seat (132b, 132c) and the drain line valve seat (132a). (Item 12) Item 12. The disposable medical fluid cassette (130) of item 11, wherein the rigid body (138) includes a rigid wall defining the common well (146), and the flexible sheet (136) is sealed to the rigid wall to surround the common well (146). (Item 13) 2. The disposable medical fluid cassette (130) of claim 1, wherein at least one of the patient line valve seat (132e), the at least one supply line valve seat (132b, 132c), or the drain line valve seat (132a) includes a tapered sealing surface (152) surrounded by a plurality of displacement ribs (154a to 154f), at least some of the displacement ribs (154a to 154f) being spaced to mitigate ingress of a flexible sheet (136) into the tapered sealing surface (152). (Item 14) 2. The disposable medical fluid cassette (130) of item 1, wherein the common well (146) includes a slope (146r) configured to direct air within the common well (146) toward the drain line valve seat (132a). (Item 15) 2. The disposable medical fluid cassette (130) of claim 1, wherein the drain line valve seat (132a) is positioned relative to the at least one supply line valve seat (132b, 132c) in the common well (146) such that the drain line valve seat (132a) is at a higher position than the at least one supply line valve seat (132b, 132c) to direct air toward the drain line valve seat (132a) when the disposable medical fluid cassette (130) is loaded for operation. (Item 16) A peritoneal dialysis system (10), comprising: A cycler (20), comprising: A pump actuator (60); a patient line valve actuator (34e); at least one supply line valve actuator (34b, 34c); A drain line valve actuator (34a) a cycler including A disposable medical fluid cassette (130) and Equipped with The disposable medical fluid cassette (130) comprises: a pumping section (126) configured to operate with the pump actuator (60); a patient line valve seat (132e) configured to operate with the patient line valve actuator (34e); a rigid body (138) defining a common well (146); at least one supply line valve seat (132b, 132c) disposed within the common well (146) and configured to operate with the at least one supply line valve actuator (34b, 34c); a drain line valve seat (132a) disposed within the common well (146) and configured to operate with the drain line valve actuator (34a); 1. A peritoneal dialysis system comprising: (Item 17) Item 17. The peritoneal dialysis system (10) of item 16, wherein the cycler (20) is configured to perform a patient drain in which used dialysate enters the common well (146), followed by a patient fill in which fresh dialysate enters the common well (146). (Item 18) Item 18. The peritoneal dialysis system (10) of item 17, wherein during the patient drain, the drain line valve actuator (34a) is actuated to allow used dialysate to exit the common well (146) through the drain line valve seat (132a), and during the patient fill, one of the at least one supply line valve actuators (34b, 34c) is actuated to allow fresh dialysate to enter the common well (146) through one of the at least one supply line valve seats (132b, 132c). (Item 19) Item 18. The peritoneal dialysis system (10) of item 17, wherein during the patient drain and the patient fill, the patient line valve actuator (34e) is actuated to allow used dialysate and fresh dialysate to flow through the patient line valve seat (132e), respectively. (Item 20) A valve seat (132a-132e) for a disposable medical fluid cassette (130), said valve seat (132a-132e) comprising: A rigid wall; a tapered sealing surface (152) extending from the rigid wall, the tapered sealing surface (152) surrounding an opening formed in the rigid wall; a displacement rib (154a through 154f) extending from said rigid wall or from an outer edge of said tapered sealing surface (152) so as to surround said tapered sealing surface (152); Equipped with The plurality of displacement ribs (154a through 154f) are spaced to mitigate unwanted obstruction of the tapered sealing surface (152), the valve seats (132a through 132e). (Item 21) Item 21. The valve seat (132a to 132e) of item 20, wherein the displacement ribs (154a to 154f) are separate from one another or extend from a common cylindrical base. (Item 22) 21. The valve seat (132a to 132e) of claim 20, wherein the tapered sealing surface (152) is cylindrical and the displacement ribs (154a to 154f) collectively form a cylindrical shape surrounding the tapered sealing surface (152). (Item 23) Item 21. The valve seat (132a to 132e) of item 20, wherein the tapered sealing surface (152) forms a funnel shape that leads to the opening. (Item 24) 21. The valve seat (132a to 132e) of item 20, wherein the opening extends from the tapered sealing surface (152) and the displacement rib (154a to 154f) through a port (140a to 140e) disposed on an opposite side of the rigid wall. (Item 25) 21. The valve seat (132a-132e) of claim 20, wherein the tapered sealing surface (152) includes at least one circular sealing ring (156) for compressing against a mating sealing member. [Brief description of the drawings]

[0172] [Figure 1] FIG. 1 is a perspective view of one embodiment of the system and associated cycler and disposable set of the present disclosure.

[0173] [Diagram 2] FIG. 2 is a perspective view of one embodiment of the working surface of a cycler of the present disclosure.

[0174] [Diagram 3] FIG. 3 is a perspective view of one embodiment of a peristaltic pump tube autoloading structure and related features.

[0175] [Figure 4] FIG. 4 is an elevational view of one embodiment of a pinch valve of the present disclosure.

[0176] [Diagram 5] 5A and 5B are elevation and cross-sectional views of one embodiment of a spring-loaded end effector valve plunger of the present disclosure.

[0177] [Figure 6] FIG. 6 is a side elevational view of one embodiment of a disposable cassette of the present disclosure adjacent the working surface of a cycler.

[0178] [Figure 7]FIG. 7 is a perspective view of one embodiment of a valve seat of the present disclosure taken along line VII-VII of FIG.

[0179] [Figure 8] FIG. 8 is a side elevational view of one embodiment of a disposable cassette of the present disclosure as viewed from outside the cycler when the disposable cassette is loaded for operation.

[0180] [Figure 9] FIG. 9 is a perspective view of the operating side of one embodiment of a disposable cassette of the present disclosure illustrating how the fluid paths and valve seats are formed.

[0181] [Figure 10] FIG. 10 is a perspective and elevational cross-sectional view illustrating several alternative embodiments of the valve seat of the present disclosure.

[0182] [Figure 11] FIG. 11 is a cross-sectional elevation view illustrating one embodiment for interfacing a pressure sensor and a pressure sensor pod of the present disclosure.

[0183] [Figure 12] FIG. 12 is a plot showing pressure sensor output versus temperature used to determine the temperature scaling coefficient for the pressure sensing scaling or offset equation of the present disclosure.

[0184] [Figure 13] FIG. 13 is a perspective view of one embodiment of a self-calibrating weigh scale that can be used with the systems and cyclers of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0185] (System Overview) Referring now to the drawings, and in particular to FIG. 1 , an embodiment of a system 10 includes an automated peritoneal dialysis ("APD") cycler 20 having a housing 22, which in one embodiment employs a peristaltic pump to operate a disposable set 120. All rigid and flexible tubing portions of the disposable set 120 may be made from one or more plastics (e.g., polyvinyl chloride ("PVC") or non-PVC materials such as polyethylene ("PE"), polyurethane ("PU") or polycarbonate ("PC"). The housing 22 of the cycler 20 may be made from any of the above plastics, and / or metals, such as stainless steel, steel and / or aluminum.

[0186] In the illustrated embodiment, the housing 22 includes a hinged door 24 having a series of holes or slots 26a, 26b, 26c, 26d, and 26e for the tubing (122a to 122e) of the disposable set 120 to extend from inside the housing 22 to outside the housing. Although shown as elongated slots, the apertures (26a to 26e) could alternatively be holes. However, the slots (26a to 26e) are advantageous for allowing the door 22 to be hinged open without placing the tubing (122a to 122e) under undue tension. In an embodiment, the tubing (122a to 122e) is pre-connected to and sterilized with a disposable pump cassette, described below. The distal ends of the tubing (122a to 122e) are removed from the sterile caps during treatment setup and secured to containers or bags (124a to 124d) of the disposable set 120 (line 122e is the patient line). The container or bag 124a can be a drain container or bag. The containers or bags 124b and 124c can be primary fresh dialysate supply containers or bags. The container 124d can be a final fill container or bag, which holds a different formulation of fresh dialysate (e.g., 2 to 3 liters of icodextrin) that is formulated to remain inside the patient's peritoneal cavity after the patient disconnects from the disposable set 120.

[0187] In the illustrated embodiment, the door 24 is positioned vertically and thus holds the set 120 of disposable cassettes within the housing 22 of the cycler 20 perpendicular to the working surface of the housing. The door 24 is positioned adjacent to the user interface portion of the cycler 20, which includes a control unit 50 having one or more processors 52, one or more memories 54, and a video controller 56, which interfaces the one or more processors 52 and the one or more memories 54 with a user interface 58. The user interface 58 may include a touch screen and / or electromechanical buttons (such as membrane switches) for inputting user commands and providing instructions, alerts, and alarms. Providing the user interface 58 next to the door 24 of the housing 22 allows the patient or other user to interact with what would normally be one surface of the device 20 for inputting commands, receiving data, and loading / unloading disposable cassettes. The user interface 58 may alternatively or additionally be a remote user interface, for example via a tablet or smartphone. The control unit 50 may also include a transceiver and a wired or wireless connection to a network (not shown, e.g., the Internet) to transmit treatment data to a physician or clinician server that interfaces with the physician or clinician computer and receive prescription orders / changes from the physician or clinician server. Data transmitted to the physician or clinician computer may be analyzed and / or converted into or used to form other data useful for analysis. Such data conversion may alternatively or additionally be performed in the control unit 50 of the cycler 20.

[0188] FIG. 1 shows that the system 10 in one embodiment also includes a bag shelf enclosure 40 that serves multiple purposes. The bag shelf enclosure 40 is sized such that the cycler 20 can be stored inside the enclosure when the cycler 20 is not in use. In the illustrated embodiment, the bag shelf enclosure 40 includes a rotatably hinged handle 42 that allows a user to transport the enclosure with the cycler 20 stored therein. As shown in FIG. 1, the bag shelf enclosure 40 is also sized such that the bag shelf enclosure can be set on top of the cycler 20 (on top of a weight plate in one embodiment, as described in more detail below) when the cycler 20 is in use. The bag shelf holds multiple containers or bags (124a to 124d), such as multiple supply containers (124b to 124d) and one or more drain containers 124a. As shown, the containers or bags are held within the enclosure 40 and on the outer top surface of the enclosure.

[0189] The bag shelf enclosure 40 may include color-coded markers 44a to 44d provided at locations for loading receptacles or bags having lines extending through slots or apertures 26a to 26d into the cycler 20, the slots or apertures having similar color-coded markers or borders. The matching color-coded markers 44a to 44d and slot borders make it easy for the patient or caregiver to identify which bag and line belongs to which location on the bag shelf enclosure 40. For example, the marker 44a and the border of the slot 26a may be green to indicate the drain line 122a and the drain receptacle 124a, and the desired location of the drain receptacle. The markers 44b and 44c and the border of the slots 26b and 26c may be blue to indicate the primary supply lines 122b, 122c and the supply receptacles 124b, 124c, and the desired location of the supply receptacle. The marker 44d and the border of the slot 26d may be red to indicate the last fill line 122d and the last fill container 124d, and the desired location of the last fill container.

[0190] (Drain / Purge) It is conceivable that the supply containers or bags, e.g., the primary supply containers or bags 124b and 124c, may be used later as drain containers or bags to reduce overall disposable costs. For example, assume that a patient is full of effluent at the start of treatment. The effluent is first drained from the patient and delivered to the drain container 124a, which is first empty. The first patient load is then delivered from the first primary supply container 124b to the patient and delivered to the same drain container 124a (or a different drain container depending on the size of the drain container) after a designated dwell period. In an embodiment, the drain container 124a and the primary supply containers 124b and 124c are larger 6 liter containers for holding multiple cycles of fresh and used dialysate. The drain container 124a is used to receive the effluent until the first supply container 124b is empty, after which the first supply container receives the effluent after the dwell period using the PD fluid delivered from the second supply container 124c. The first supply container 124b is used to receive the patient effluent, possibly over multiple patient fills, dwells and drains, until the second supply container 124c is empty. At that point, the patient may receive a final fill of a different formulation of peritoneal dialysis fluid from the last fill container 124d, which remains in the patient until the next night's treatment, or perhaps until the daytime exchange. If the second supply container 124c is empty at the end of a treatment, it may be used as the first empty drain container at the start of the next treatment, further reducing disposable waste and costs.

[0191] In one example, the containers (124a through 124d) may be used as follows when the patient is initially full: Initial drain → Drain container 124a Supply vessel 124b → First fill → Drain vessel 124a Supply vessel 124b → Second fill → Drain vessel 124a Supply vessel 124c → 3rd filling → supply vessel 124b Supply vessel 124c → 4th filling → supply vessel 124b Last filled container 124d-last filled

[0192] In one example, the containers (124a through 124d) may be used when the patient is initially empty as follows: Supply vessel 124b → First fill → Drain vessel 124a Supply vessel 124b → Second fill → Drain vessel 124a Supply vessel 124c → 3rd filling → supply vessel 124b Supply vessel 124c → 4th filling → supply vessel 124b Last filled container 124d-last filled

[0193] At the end of the treatment, multiple containers or bags (e.g., containers 124a, 124b) are filled with effluent. The remaining supply container 124c may also contain remaining fresh dialysate. To prevent the patient or caregiver from having to transport the complete drain bag to a house drain, e.g., a toilet, sink, or bathtub, the control unit 50 of the cycler 20 is programmed to prompt the user to disconnect the patient line 122e from the patient's transfer set and carry the distal end of the patient line 122e to a house drain. If necessary, a reusable extension line 122f may be connected to the distal end of the patient line 122e to reach the house drain. The patient or caregiver then presses a drain button on the user interface 58, at which time the cycler 20 operates a pump actuator, e.g., a peristaltic pump actuator, in a direction to draw spent dialysate or effluent from each of the drain containers 124a, 124b (one or more of which may be the original supply container) and pump the spent dialysate through the patient line 122e (and extension line 122f, if necessary) to the house drain. Remaining fresh dialysate is removed from the supply container 124c in a similar manner. The drain button in an embodiment is only displayed at the end of treatment when the button is needed, e.g., via a touch screen display. Alternatively, the drain button may be a membrane switch that is only enabled at the end of treatment when the button is needed. Additionally, the drain button, regardless of its type, may be displayed and / or enabled only after the patient presses a confirmation button provided by the user interface 58 in response to a prompt by the user interface for the patient or caregiver to confirm that the patient line 122e / 122f is extended to the house drain.

[0194] The control unit 50 of the cycler 20 detects when each drain container 124a, 124b is empty (e.g., via a weight scale and / or pressure sensor operating on a pressure pod of the disposable cassette, as described in more detail below) and automatically switches a valve actuator, such as a pinch valve actuator, to sequence between the drain containers 124a, 124b (and the supply container 124c, if necessary) until each is empty. In particular, the cycler 20 includes a patient valve actuator that operates with a patient valve seat provided by the disposable set 120 and a drain valve actuator that operates with a drain valve seat provided by the disposable set, and the control unit 50 is configured to cause the patient valve actuator and the drain valve actuator to enable flow through the drain valve seat and the patient valve seat to pump spent dialysate from the drain container through the patient line to the house drain. It should be understood that multiple drain containers (one or more of which may be previous supply containers) may be drained simultaneously over the same or overlapping periods, e.g., to save time.

[0195] It is contemplated that the control unit 50 may look for remaining fresh dialysate in any remaining supply containers, such as containers 124c and 124d, and cause the pump actuator to pump the remaining fresh dialysate to the drain via the patient line. In this manner, when the patient disconnects from patient line 122e and presses the drain button, the patient may assume that all fresh and used dialysate has been pumped to the house drain, and thus may be free to begin the patient's day.

[0196] Although the system 10 is described in this section as pumping effluent or remaining fresh dialysate to a house drain, it should be understood that in alternative embodiments, the control unit 50 may pump any remaining fluid (fresh or used) from any container (124a to 124d) to any other container (124a to 124d). In an embodiment, after a procedure in which the patient disconnects from the patient line 122e, the patient places the distal end of the patient line in a priming holder (not shown) located in the housing 22 of the cycler 20 and confirms this action in the user interface 58. The distal end of the patient line 122e remains open to the atmosphere. The control unit 50 then executes a sequence in which all fluid currently present in the patient line 122e is pumped to the desired destination container (124a to 124d) and the patient line 122e is completely or nearly completely filled with air. The control unit 50 then causes any dialysate (fresh or spent) delivered to any container (124a to 124d) to be moved via the peristaltic pump actuator 60 rotating in the patient fill direction for a known number of strokes to push the amount of fluid through the in-line fluid heating path 144 and into a safe portion of the patient line 122e so that the fluid does not spill out the end of the patient line. The control unit 50 then reverses the direction of the peristaltic pump actuator 60 to rotate in the patient drain direction for a known number of strokes and changes the valve state of the associated valve actuator to push the amount of fluid through the safe portion of the patient line 122e and the in-line fluid heating path 144 to the desired destination container (124a to 124d). The control unit 50 then repeats the pumping and back-pumping actions until the desired amount of fresh or spent dialysate has been moved from the desired source container (124a to 124d) to the desired destination container (124a to 124d).

[0197] (Automatic loader) Referring now to FIG. 2, one embodiment of the active face 30 of the cycler 32 is shown. The active face 30 in FIG. 1 is hidden behind the door 24. When the door 24 is opened, the active face 30 as shown in FIG. 2 is exposed. The labels "top", "bottom", "user interface" and "patient end" are shown in FIG. 2 to show how the active face 30 is oriented in FIG. 1. The active face 30 in the illustrated embodiment includes a heater 32 (such as a resistive plate that heats an in-line fluid heating path provided by a disposable cassette, as shown below). The active face 30 also includes a number of valve actuators (34a through 34e), including a drain line valve actuator 34a, a main supply line valve actuators 34b and 34c, a final fill line valve actuator 34d, and a patient line valve actuator 34e. An embodiment of the valve actuators (34a through 34e) is shown in more detail below. The active face 30 also includes a number of pressure sensors (including a patient pressure sensor 36a and a pumping pressure sensor 36b). Embodiments of pressure sensors 36a and 36b are similarly described in detail below. At least one temperature sensor 38, e.g., a thermocouple or thermistor, is also provided. A control unit 50, figuratively shown in Figure 2, controls the heater 32 and the valve actuators (34a to 34e) and receives inputs from the pressure sensors 36a, 36b and the temperature sensor 38.

[0198] FIG. 2 further illustrates that a peristaltic pump actuator 60, under the control of the control unit 50, is disposed on and extends behind the working surface 30 of the cycler 20. The pump actuator 60 may include a pump head 62 disposed on the working surface 30 and a driver or motor 64 disposed behind the working surface 30. The disposable cassette includes a peristaltic pump tube, and when loading the cassette, a user guides the peristaltic pump tube over the pump head 62 of the peristaltic pump actuator 60. During operation, the peristaltic pump actuator 60 compresses the peristaltic pump tube against the track 66 at multiple points. The operative proximity of the track 66 to the peristaltic pump actuator 60 makes loading the tube difficult. Thus, the present cycler 20 provides a movable track 66 that translates out of the way of the peristaltic pump actuator, e.g., via a linkage (not shown), when a patient or caregiver opens the door 24 of the cycler 20 to load the disposable cassette. After the cassette is loaded, closing the cycler door 24 translates the movable track 66, for example via a linkage, to an operational position directly adjacent the peristaltic pump tubing. In an alternative embodiment, a motor and lead screw assembly, or linear actuator (e.g., a linear stepper motor, not shown) is provided to automatically translate the track 66 out of the way of the peristaltic pump actuator 60 when the patient or caregiver opens the door 24 to load the cassette, and to automatically translate the track 66 to an operational position when the door 24 is closed. In a further alternative embodiment, a motor and lead screw assembly, or linear actuator (e.g., a linear stepper motor, not shown) is provided, but the patient or caregiver instead presses one or more buttons on the user interface 58 to translate the track 66 out of the way or to an operational position.

[0199] In an embodiment, the track 66 is mounted to a block or member 70 that is translatable across the actuation surface 30 toward and away from the peristaltic pump actuator 60. In addition to the translational movement of the member 70 (and the track 66), the movable track 66 can also rotate about a pivot 72 provided at one end 66a of the track 66, which is mounted to the translatable member 70. The other end 66b of the track 66 is spring loaded via a spring 74, e.g., a compression spring, trapped between the track end 66b and the member 70. In the illustrated embodiment, the spring 74 is inserted over a threaded bolt 76 that extends through the track end 66b and is threaded into the member 70. The threaded bolt 76 includes a head 76h that sets the end of spring travel for the track 66, which can be adjusted in or out by rotating the threaded bolt 76 clockwise or counterclockwise, respectively. In the illustrated embodiment, spring 74 urges track 66 about pivot 72 to a desired operating position about the peristaltic pump tubing after member 76 is translated toward peristaltic pump actuator 60. Pivoting track 66 may provide a damping effect to absorb or tolerate variations due to tubing tolerances and aid in noise reduction.

[0200] 2 and 3 show that the member 70 and track 66 slide along a linear rail 68 formed or provided along the working surface 30. The member 70 includes a rail receiver (not visible) on its underside sized to fit and operate with the linear rail 68. The rail receiver in the embodiment interacts with the linear rail 68 via, for example, a tongue and groove fit, such that the linear rail 68 holds the member 70 and track 66 in sliding engagement along the working surface 30. Additionally or alternatively, FIG. 3 shows that the member 70 may have an elongated slot 78 formed therein that receives a bolt that may be loosely tightened so that the member 70 and track 66 may slide along the working surface 30 while still being held to the surface.

[0201] Section IIIA of FIG. 3 shows the peristaltic pump tubing 126 of the disposable set 120 as it is about to be loaded. The member 70 and track 66 are in a fully retracted or out of the way position. Section IIIB of FIG. 3 shows the peristaltic pump tubing 126 being extended or placed into an operable position about the pump head 62 of the peristaltic pump actuator 60. The member 70 and track 66 are again in a fully retracted or out of the way position. Section IIIC of FIG. 3 shows the member 70 and track 66 being translated into an operable position relative to the peristaltic pump tubing 126 and pump head 62 of the peristaltic pump actuator 60.

[0202] As mentioned above, a purely mechanical linkage (not shown) may be provided which pulls member 70 and track 66 to the fully retracted or out of the way position of sections IIIA and IIIB of FIG. 3, e.g., the linkage is actuated by the opening of door 24. The linkage pushes member 70 and track 66 to the operable position of section IIIC of FIG. 3, e.g., the linkage is actuated by the closing of door 24. Alternatively, a motorized mechanism such as a linear actuator or a motor and lead screw may be provided to (i) automatically pull member 70 and track 66 to the fully retracted or out of the way position of sections IIIA and IIIB of FIG. 3 when door 24 is opened, and (ii) automatically push member 70 and track 66 to the operable position of section IIIC of FIG. 3 when door 24 is closed. Further alternatively, if it is desirable to be able to access actuation surface 30 when members 70 and tracks 66 are in the operational position, a button may be provided on user interface 58 to activate the motorized mechanism, for example, to both retract and extend members 70 and tracks 66, or, in some cases, only to extend members 70 and tracks 66 to the operational position after being automatically pulled to the fully retracted position upon opening door 24. Control unit 50 may be programmed to perform any of such sequences.

[0203] As shown in fully retracted sections IIIA and IIIB of FIG. 3, member 70 includes a base 70b that defines an arc having a radius that at least substantially coincides with the radius of track 66. It is contemplated that head 76h of bolt 76 provides a stop arranged to stop the pivoting of track 66 via spring 74 (e.g., by threading bolt 76 outboard of member 70) when the radius of track 66 at least substantially reaches and thus coincides with the radius of the arc of base 70b. As mentioned above, track 66 is movable primarily for ease of loading. A secondary benefit of the translational motion is adjustment of track position to optimize tube variability. Pivoting via pivot 72 and spring 74 aids in accommodating tube tolerances and provides a damping effect that aids in noise reduction. Although spring 74 is shown as a compression spring, it should be understood that the spring could alternatively be an extension spring or other type of spring.

[0204] (Spring end effector) 4, 5A and 5B, there are shown any or all of the embodiments of the pinch valve actuators (34a to 34e). A disposable cassette 130 (e.g., injection molded or blow molded plastic) is provided with valve seats (132a to 132e) that receive the pinch valve actuators (34a to 34e) for occluding or closing the fluid paths 134 provided by the disposable cassette, respectively. In FIG. 4, the disposable cassette 130 is sealed (e.g., ultrasonically welded, heat sealed, and / or solvent bonded) and covered by a flexible sheet 136, e.g., flexible plastic, and the pinch valve actuators (34a to 34e) close the respective fluid paths 134 by pressing a portion of the flexible plastic against the respective valve seats (132a to 132e). The pinch valve actuators (34a to 34e) retract to open the respective fluid paths 134. As shown in FIG. 4, the openings in the valve seats (132a to 132e) extend through the rigid body 138 of the disposable cassette 130 and through the ports (140a to 140e), which extend in a direction away from the valve seats. Each of the lines or tubes (122a to 122e) is sealably connected, for example, by ultrasonic welding, heat sealing and / or solvent bonding, to each of the ports (140a to 140e). The lines or tubes (122a to 122e) extend from the disposable cassette 130 through the door 24 via respective slots or apertures (26a to 26e), as shown in FIG.

[0205] As shown in FIG. 4, each of the pinch valves (34a to 34e) is driven by a linear actuator 80, which may be any suitable type of linear actuator, such as a linear stepper motor that provides the required amount of travel (e.g., up to 10 mm) and the required amount of pressurized cassette seat closing force (e.g., 30 to 60 Newtons ("N") or less) under the control of the control unit 50. In the illustrated embodiment, the linear actuator 80 is mounted to an interior wall 46 or other internal structure within the housing 22 of the cycler 20 such that a valve plunger 84 connected to an output shaft 82 of the linear actuator 80 extends through a hole 30h in the actuation face 30 just to meet a flexible valve membrane 48, e.g., flexible silicone, bolted to the actuation face 30. The linear actuator 80 drives the valve plunger 84 to press the flexible membrane 48 and a portion of the cassette seat 136 against a respective cassette valve seat (132a to 132e). Linear actuator 80 retracts valve plunger 84, allowing it to be unseated from each cassette valve seat (132a to 132e), for example, via its own resilience and positive fluid pressure.

[0206] As shown in Figures 5A and 5B, the valve plunger 84 in one embodiment includes a proximal end effector 86 that couples to the linear actuator 80 and a distal end effector 90 that is slidably coupled to the proximal end effector 86. As shown in Figure 5B, the proximal end effector 86 has a larger diameter portion 86a and a smaller diameter portion 86b. The distal end effector 90 includes or defines a cylindrical opening 92 that slidably receives the smaller diameter portion 86b of the proximal end effector 86. In the illustrated embodiment, the spring 98 is disposed between a step 86c that transitions between the larger diameter portion 86a and the smaller diameter portion 86b and a proximal edge 90p of the distal end effector 90. Thus, the spring 98 is constrained by the smaller diameter portion 86b of the proximal end effector 86. 5A and 5B show that the outer diameter of distal end effector 90 can be at least substantially equal to the outer diameter of larger diameter portion 86 a of proximal end effector 86 .

[0207] One of the proximal end effector 86 or the distal end effector 90 defines at least one groove, and the other of the proximal end effector or the distal end effector includes at least one spring arm that mechanically fits (e.g., snaps into) the at least one groove to slidably attach the end effectors to one another. In the illustrated embodiment, the proximal end effector 86 defines at least one groove 88, and the distal end effector 90 includes or defines a plurality of spring arms 94a, 94b...94n that mechanically fit (e.g., snaps into) the at least one groove 88. If it is desired that the distal end effector 90 not spin relative to the proximal end effector 86, a separate groove 88 can be defined for each spring arm 94a, 94b...94n. If this is not an issue, a single annular groove 88 can be provided instead. In either case, the length of the at least one groove 88 is sized to provide a length of travel of the distal end effector 90 relative to the proximal end effector 86 that is equal to or greater than the uncompressed length of the spring 98 .

[0208] The spring 98 can be a wave or compression spring. One allowable travel length of the spring 98 is 2.9 mm. In an embodiment, the spring 98 is configured to provide the 25 N sealing force necessary to properly seal the cassette seat 136 against the valve seats (132a to 132e) after approximately 1.4 mm of compression travel. The spring 98 can exert a maximum force of 51 N at the solid height, with the linear actuator 80 being selected to have at least a slightly higher peak force.

[0209] The spring 98 is positioned to bias the distal end effector 90 outwardly against the proximal end effector 86. The variable distance provided by the spring 98 allows the pinch valves (34a to 34e) to initially contact the cassette seat 136 (through the flexible membrane 48) with a smaller closing force that steadily increases as the spring 98 is compressed. The flexible membrane 48 is secured to the actuation surface 30 to cover the end of the distal end effector 90. When the spring 98 is fully compressed, the cassette seat 136 and valve seats (132a to 132e) experience the full closing force of the linear actuator 80 and spring 98. The spring 198 thus provides a force buffer that aids in protecting the flexible membrane 48 over multiple procedures and protecting the cassette seat 136 over a single procedure. The spring 98 may also account for variations due to tolerances of the disposable cassette 130 and its loading, further allowing for a smaller or less expensive linear actuator 80.

[0210] (Disposable cassette / valve seat) 6-10, the disposable cassette 130 in the illustrated embodiment provides multiple valve seats, which may include a patient line valve seat 132e, first and second supply line valve seats 132b, 132c, a final fill line valve seat 132d, and a drain line valve seat 132a. In the embodiment shown in FIGS. 6 and 9, the patient line valve seat 132e is fluidly separated from the first peristaltic tube port 142a by an in-line fluid heating path 144, e.g., a serpentine path. When the disposable cassette 130 is installed for operation, the in-line fluid heating path 144 is adjacent to a heater 32, such as the resistive plate heater shown in FIG. 2. FIG. 9 shows that a flexible sheet 136 is sealed to a rigid body 138 over the fluid heating path 144, allowing heat to be transferred through the thin-walled sheet to fresh dialysate moving through the path.

[0211] 6 and 9 show that in one embodiment, each of the first and second supply line valve seats 132b, 132c, the last fill line valve seat 132d, and the drain line valve seat 132a are disposed in a common well 146 in fluid communication with the second peristaltic tube port 142b. The peristaltic pump tubing 126 is attached (e.g., ultrasonically welded, heat sealed, and / or solvent bonded) to the tube ports 142a and 142b. Thus, fresh dialysate can be pumped in a first direction from either the supply container (124b to 124d) for the first and second supply line valve seats 132b, 132c or the last fill line valve seat 132d through the common well 146 and the in-line fluid heating pathway 144, where the fresh dialysate is heated and then delivered to the patient from the patient line valve seat 132e. Spent dialysate or effluent can be pumped from the patient in a second direction through the patient line valve seat 132e and the in-line fluid heating path 144 (where the spent dialysate is not heated) into the common well 146, from the drain line valve seat 132a to the drain container 124a.

[0212] The common well 146 simplifies the fluid path of the cassette 130. The drain line valve seat 132a is located closest to the peristaltic tube port 142b, so that the used dialysate travels a minimum distance within the well 146 before reaching the drain line valve seat. FIG. 8, showing the non-operating side of the disposable cassette 130, shows the drain port 140a, the supply container ports 140b, 140c, and the final fill container port 140d extending from the rigid body 138 on the other side from the common well 146. Again, the drain port 140a, to which the drain line 122a is ultrasonically welded, heat sealed, and / or solvent bonded, is located directly adjacent to the peristaltic tube port 142b, so that the used dialysate is removed from the common well 146 as quickly as possible to reduce mixing with the fresh dialysate remaining in the well. Supply container lines 122b, 122c, final fill container line 122d, and patient line 122e are similarly ultrasonically welded, heat sealed, and / or solvent bonded to supply container ports 140b, 140c, final fill container port 140d, and patient line port 140e, respectively.

[0213] 7 and 10 illustrate that any of the valve seats (132a through 132e) described herein may include a tapered sealing surface 152 surrounded by a plurality of displacement ribs (154a through 154f), which may extend from the rigid body 138 of the disposable cassette 130, at least some of the displacement ribs (154a through 154f) spaced apart by gaps G that prevent or mitigate unwanted blockage of the tapered sealing surface 152 by the flexible sheet 136 and allow fresh or used dialysate to flow through the gaps G. The displacement ribs (154a through 154f) may be completely separate from one another (see examples XC through XE of FIG. 10) or may extend from a common cylindrical base (see examples XA and XB of FIG. 10). The displacement ribs (154a to 154f) may also be separate from the tapered sealing surface 152 (see examples XB, XC, and XE of FIG. 10) or may extend from or be connected to the outer edge of the tapered sealing surface (see examples XA and XD of FIG. 10). The displacement ribs (154a to 154f) help guide the pinch valve plunger 84 toward the center of the valve seat (132a to 132e) while providing a certain amount of resiliency or play between the pinch valve plunger and the valve seat. In an embodiment, the tapered sealing surface 152 tapers to form a funnel shape that leads to an opening that allows fresh or used dialysate to flow into or out of the valve seat (132a to 132e). In an embodiment, the opening extends through a port (140a to 140e) located on the other side of the rigid body 138 of the disposable cassette 130 (FIG. 8). The tapered sealing surface 152 may also include or define one or more circular sealing rings 156 that compress the flexible sheet 136 when the flexible sheet is closed by the pinch valves (34a through 34e).

[0214] In an embodiment, a first or patient pressure sensing pod 150a is disposed within the disposable cassette 130 directly adjacent to the patient line valve seat 132e. The patient pressure sensing pod 150a when the disposable cassette 130 is loaded outputs to the first or patient pressure sensor 36a which outputs to the cycler control unit 50. The output of the patient pressure sensor 36a can be used to control the positive and negative pumping pressures experienced by the patient to be within safe pressure limits, for example, 0.21 bar (3 psig) positive and -0.10 bar (-1.5 psig) negative. A second or pumping pressure sensing pod 150b is disposed within the disposable cassette 130 between the common well 146 and the second peristaltic tube port 142b. The pumping pressure sensing pod 150b when the disposable cassette 130 is loaded is adjacent to a second or pumping pressure sensor 36b, which outputs to the cycler control unit 50. The output of the pumping pressure sensor 36b can be used to detect blockages in the supply and drain lines and / or empty conditions of the supply and drain containers. For example, a spike in positive pressure from the pumping pressure sensor 36b can indicate a blockage in the drain line 122a or the patient line 122e. In another example, a sudden increase in negative pressure from pumping pressure sensor 36b may indicate (i) an obstruction in patient line 122e or supply line (122b to 122d), (ii) an empty supply container 124b, 124c, or last fill container 124d during treatment, or (iii) an empty supply container 124b, 124c, last fill container 124d, or drain container 124a at the end of treatment when attempting to drain remaining unused or used treatment fluid.

[0215] The disposable cassette 130 may also include one or more regions 148 adjacent a thermocouple or other type of temperature sensor 38 that, when on-board for operation, outputs to the control unit 50. The temperature sensing region 148 may be located, for example, at the end of the in-line fluid heating pathway 144 directly adjacent a patient pressure sensing pod 150a, so that the outlet temperature of the fresh dialysate to the patient may be monitored and controlled to a desired temperature, for example, body temperature or 37°C, via a proportional, integral, derivative ("PID") routine executed by the control unit 50 using feedback from the temperature sensor 38. A second temperature sensor and associated cassette temperature region (not shown) may be positioned to detect the temperature at the inlet to the in-line fluid heating pathway 144, as needed, which may likewise provide useful information for the PID routine.

[0216] FIG. 6 shows the vertically positioned disposable cassette 130 as it is loaded for operation against the working surface 30, the cassette including multiple features to enhance priming and air handling. With further reference to FIG. 1, it should be understood that a key feature of the overall system 10 to prevent air from reaching the patient is the location of the fresh dialysate supply containers or bags (124b and 124c) and the last filled container or bag 124d, which are higher than the location where the disposable cassette 130 is loaded against the working surface behind the door 24. Here, air tends to remain within the containers or bags (124b to 124d) and not be delivered to the disposable cassette 130. Although not shown, it is contemplated to provide a structure within and on top of the bag shelf enclosure 40 that raises the rear end of each container or bag (124b to 124d) relative to the forward discharge end of the container. In this way, air tends to move away from the connection of the bag to the respective tube (122b to 122d) and toward the rear of the container (124b to 124d).

[0217] It is also contemplated to place an air sensor or detector (not shown), which may be an ultrasonic sensor with an emitter pair and a receiver pair on either side of the hole or slot (26b to 26d) as shown in FIG. 1. The air sensor or detector outputs their output signal to the control unit 50 which monitors it. If air is detected, the control unit 50 (i) stops the peristaltic pump actuator 60 from pumping further towards the patient, (ii) closes the corresponding supply valve seats (132b to 132d) shown in FIG. 6, (iii) opens the drain valve seat 132a, and (iv) reverses the peristaltic pump actuator 60 to push the dialysate with entrained air into the drain line 122a and the drain container 124a.

[0218] FIG. 6 shows that the drain valve seat 132a is positioned higher than the supply valve seats (132b through 132d) to help air move toward the drain valve seat. Additionally, the top of the common well 146 is provided with a slope 146r to direct air upward toward the drain valve seat 132a. FIG. 6 further shows that the pumping pressure sensing pod 150b is provided with an inlet lower than the top of the slope 146r so that air is encouraged to float away from the pumping pressure sensing pod 150b toward the drain valve seat 132a. FIG. 6 further shows that the outlets of the patient and pumping pressure sensing pods 150a and 150b are directed upward and at a relatively high position, so that air tends to leave the pods and aid in the accuracy of the fresh and used dialysate pressure measurement.

[0219] To aid in priming, the serpentine fluid heating path 144 meanders upward to help air exit the disposable cassette 130 during priming through the patient line valve seat 132e and the patient line 122e to atmosphere. The patient line valve seat 132e, like the drain line valve seat 132a, is positioned relatively high when the disposable cassette 130 is loaded for operation. During priming, the distal end of the patient line 122e is held in a priming holder (not shown) located on the housing 22 of the cycler 20. An additional air detector or sensor (not shown), such as an ultrasonic sensor, outputting to the control unit 50, may be incorporated into the priming holder to detect when the patient line 122e is fully primed with fresh dialysate. It is also contemplated to position an additional air sensor or detector (not shown) for the patient line, which may be an ultrasonic sensor having an emitter and receiver pair located on either side of the patient line hole or slot 26e shown in FIG. 1. The additional air sensor or detector outputs its output signal to the control unit 50 which monitors it. If air is detected in the patient line 122e, the control unit 50 executes air purge procedures (i) through (iv), forcing the air through the fluid heating pathway 144 and into the drain container or bag 124a.

[0220] (Pressure Sensor) 11, in one embodiment, the cycler 20 of the system 10 mounts pressure sensors 36a, 36b on or in association with the working surface 30 of the cycler such that they are within holes 30h in the working surface 30, such that when the disposable cassette 130 is loaded for operation, the cassette sheet 136 (which may be polyvinyl chloride ("PVC") or any of the other polymers listed herein) is contacted and placed under tension by the pressure sensors 36a, 36b, generating a baseline or preload force Fp that is measured by the pressure sensors. FIG. 11 shows a possible diameter of the contact heads of the pressure sensors 36a, 36b, i.e., 10 mm, which also provides an indication as to the size or diameter of the pressure pods 150a, 150b of the disposable cassette 130. Fresh or spent dialysate pressure P further displaces (or attempts to displace) the cassette sheet 136, thereby increasing or decreasing the counter fluid force Fr acting on the pressure sensors 36a, 36b relative to the baseline or preload force Fp. The force difference between Fr and Fp caused by the positive or negative fluid pressure P is correlated by the control unit 50 with an actual fluid pressure value, which is used for pressure control as described herein, which may be displayed by the user interface 58 and / or stored for delivery to a remote server computer for evaluation.

[0221] Pre-tensioning of the cassette sheet 136 by the pressure sensors 36a, 36b results in a pressure sensing area with high sensitivity and resolution, but it may tend to be temperature sensitive. It is therefore conceivable to program the control unit 50 to compensate the pressure readings for temperature. Here, the voltage output (which may be a current output) from the pressure sensors 36a, 36b is modified by adding an offset component, which is a function of the measured temperature (e.g., using the temperature sensor 38 and temperature sensing area 148 described above) multiplied by an empirically determined temperature scaling factor to form a compensated voltage output, which is converted to or correlated to a compensated positive or negative pressure. One suitable scaling or offset algorithm stored in the control unit 50 is as follows: V T =V 0 +gT, in the formula, V 0 is the output from the pressure sensors 36a, 36b, V T is the corrected pressure output used henceforth by the control unit 50, g is the temperature scaling factor, T is the sensed temperature.

[0222] FIG. 12 shows a plot used to determine the temperature scaling factor g for the scaling or offset algorithm described above. For each of the four plot lines, the baseline or preload Fp of the pressure sensors 36a, 36b was observed during a 30 minute fluid dwell period for fluids maintained at different temperatures ranging from 15° C. to 40° C. (typical dialysate temperatures). An equation was determined to characterize each line, as shown in FIG. 12. Each equation takes the form y=mx+b, where (i) y is the temperature scaling factor g as described above. T and (ii) b is the above V 0(iii) x is the measured temperature T as described above, and (iv) m is the scaling factor g as described above. The m values ​​from each trial were averaged to form the scaling factor g used in a scaling or offset algorithm stored in control unit 50.

[0223] In an embodiment, the control unit 50 is configured to update a compensation algorithm for adjustments in the measured temperature T (i) each time the output from the pressure sensor is read by the control unit or (ii) periodically. The control unit 50 uses the corrected output V from the pressure sensors 36a, 36b to at least one of: (a) control the medical fluid pump actuator to pump within the patient's positive or negative pressure limits; (b) determine a line occlusion condition; and / or (c) determine an empty condition of the fresh dialysate or used dialysate container during or after treatment. T It is configured to use

[0224] As discussed above, pre-tensioning of the cassette sheet 136 via the pressure sensors 36a, 36b results in a pressure sensing regime with high sensitivity and resolution, but may also be prone to mechanical creep sensitivity. To combat creep sensitivity, the control unit 50 is programmed in one embodiment to pre-condition the cassette sheet 136 prior to treatment, e.g., during set-up, so that much of the pressure signal fluctuation due to creep is eliminated before measurements from the pressure sensors 36a, 36b become significant. To do so, after the disposable cassette 130 is primed for treatment, the control unit 50 causes all pinch valves (34a through 34e) to close and then actuates the peristaltic pump actuator 60 to pressurize the interior of the cassette 130, including the sheets of pressure pods 150a, 150b, stretching the cassette sheet. The control unit 50 may be programmed to cause the pump actuator 60 to oscillate the cassette fluid pressure up and down cyclically multiple times, possibly in different directions, over a specified period of time. The high pressure may be, for example, 100% to 150% of the maximum operating pressure set for the procedure, which may be higher than the patient's pressure limit. For example, the pressure used during priming or drain purging as described above may be higher, for example, 0.50 bar (7.25 psig) or higher. Preconditioning the cassette seat 136 helps make the uncompensated pressure reading more accurate, while temperature compensation helps make the final pressure reading more accurate.

[0225] (Load cell calibration) 13, the system 10 and cycler 20 of the present disclosure, in one embodiment, uses a weigh scale 100 that includes multiple operating load cells (102a through 102d) to monitor the amount of fresh dialysate delivered to the patient, the amount of spent dialysate removed from the patient, and from there enable the control unit 50 to calculate the amount of ultrafiltration ("UF") removed from the patient. The weigh scale and load cells are advantageous for several reasons. First, the weigh scale 100 is relatively accurate compared to other volume measurement techniques. Second, the weigh scale 100 reduces pump costs because the pump actuator 60 can be a relatively simple peristaltic pump actuator and the disposable portion of the pump can be a simple peristaltic pump tubing 126.

[0226] One drawback of using load cells is calibration. Load cells can read inaccurately over time and therefore need to be recalibrated. The present cycler 20 and associated system 10 provides a weigh scale 100 having multiple load cells (102a to 102d) and an on-board structure 110 and associated methodology for calibrating the weigh scale 100. In one embodiment, the weigh scale 100 includes a weight plate 104 disposed on top of the cycler 20 that supports the weight of the bag shelf enclosure 40 and the solution and drain containers (124a to 124d) and associated fresh and used dialysate, respectively. The weight plate 104 and each weighed item on the weight plate are supported by multiple, e.g., four, load cells (102a to 102d) that collectively measure the total mass (bag shelf enclosure 40, containers (124a to 124d) and fluid) disposed on the weight plate. The on-board calibration structure 110 in one embodiment includes a linear actuator 112 (which may be of the same type used for pinch valves and may include, for example, a motor and lead screw, or a linear stepper motor) and a fifth or calibration load cell 114 disposed below the linear actuator 112, which includes an actuation output shaft 116 secured to the weight plate 104. The actuation output shaft 116 may, for example, extend through a hole formed in the weight plate 104 and be capped above the upper surface of the weight plate so as to be able to apply a downward force to the plate. Alternatively, the actuation output shaft 116 may be bolted to the underside of the weight plate 104, or may slide into a groove formed in the underside of the weight plate 104, or may be screwed into the underside of the weight plate 104, or may include a flange having some alternative mechanical connection to the weight plate 104.

[0227] The linear actuator 112 in one embodiment is actuated to apply a pulling or downward force to the weight plate 104. In one implementation, the force is applied to the center of mass CM of the weight plate 104, as shown in FIG 13. The operating load cells (102a through 102d) in the embodiment are each at least substantially equidistant from the center of mass CM and spaced apart from one another at equal x coordinate distances (e.g., the distance between the junctions of load cells 102a and 102b is the same as the distance between the junctions of load cells 102d and 102c) and equal y coordinate distances (e.g., the distance between the junctions of load cells 102a and 102d is the same as the distance between the junctions of load cells 102b and 102c).

[0228] An additional calibration load cell 114 measures the total pulling or downward force applied by the linear actuator 112, and the four operating load cells (102a through 102d) each measure a portion or quarter of the total force. If each of the operating load cells (102a through 102d) is operating properly, the sum of their outputs should equal the total force measured by the calibration load cell 114. In one example, assume a pulling force of 1000 Newtons ("N") is applied by the linear actuator 112. The calibration load cell 114 should output 1000N, while the operating load cells (102a through 102d) should each read 250 Newtons, totaling 1000N.

[0229] Because the calibration load cell 114 is used infrequently, the calibration algorithm is applied assuming that the output of the calibration load cell 114 is more accurate than the aggregate output of the working load cells (102a-102d) used throughout each procedure. Thus, during calibration, if there is a discrepancy between what the calibration load cell 114 reads and the aggregate output of the working load cells (102a-102d), the control unit 50 using the calibration algorithm will scale or offset the aggregate output of the working load cells (102a-102d) to match the aggregate output of the calibration load cell 114. In the above example, assume that the working load cells (102a-102d) actually collectively read 995N and not 1000N. Thus, the working load cells (102a-102d) are reading 0.5% under. Thereby, the control unit 50 of the cycler 20 is configured to correct the collective output of the motion load cells (102a through 102d) during treatment by a calibration factor of 1000 / 995 or 1.005.

[0230] The load cell calibration routine or algorithm of the system 10 is executed on any desired basis, for example, before the start of each treatment. The control unit 50 controls the duration of the pump actuator 60 operation (patient fill or drain) using, for example, offset output pressures from the operating load cells (102a to 102d). The control unit 50 is configured to not cause the linear actuator 112 to supply force during such operation duration. In another example, the control unit 50 is configured to determine a mass or volumetric flow rate during a treatment using two or more offset outputs from the operating load cells (102a to 102d). In a further example, the control unit 50 is configured to determine an amount of fresh dialysate delivered using at least two offset outputs from the operating load cells (102a to 102d). In yet another example, the control unit 50 is configured to determine an amount of used dialysate delivered using at least two offset outputs from the operating load cells (102a to 102d). In yet a further example, the control unit 50 is configured to use at least two offset outputs from the operating load cells (102a through 102d) to determine the amount of used dialysate delivered to or removed from the patient.

[0231] It should also be appreciated that since many of the weight values ​​monitored and collected during treatment are weight differences, errors in the aggregate output of the operating load cells (102a to 102d) tend to cancel out, assuming the errors do not change over the course of treatment. For example, the mass associated with a patient fill volume of, say, 2 liters, is monitored and controlled by the aggregate output of the operating load cells (102a to 102d) by recording the drop in mass over the course of the patient fill. The volume and mass associated with the patient drain may be preset in the control unit 50, for example, multiplying the fill volume by a factor such as 1.3 to account for the patient UF removed into the drain volume. The volume and mass associated with the patient drain may alternatively be left open ended and instead controlled by sensing a characteristic rise in negative pressure by the pumping pressure sensing pod 150b and associated pressure sensor 36b, which indicates that the patient is essentially fully drained and that further draining may be uncomfortable for the patient. In either case, the motion load cells (102a through 102d) sense an increase in weight over the course of the patient drain that should tend to offset the motion load cell errors.

[0232] It should be understood that various modifications and alterations to the presently preferred embodiments described herein will be apparent to those skilled in the art. Accordingly, such modifications and alterations are intended to be covered by the appended claims. For example, although the system 10 discloses peristaltic pumping, membrane pumping or volumetric pumping may be used instead. Although the system 10 discloses in-line heating, batch heating may be used instead. Furthermore, although the calibrated load sensing is disclosed in connection with a supply container and a drain container, the calibrated load sensing may instead be used with a dialysis solution preparation unit that pumps to one or more weight containers disposed on a weight plate.

Claims

1. 1. A valve seat for a disposable medical fluid cassette, the valve seat comprising: A rigid wall; a tapered seal surface extending from the rigid wall, the tapered seal surface surrounding an opening formed in the rigid wall; a plurality of displacement ribs extending from the rigid wall or from an outer edge of the tapered seal surface so as to circumscribe the tapered seal surface; Equipped with The displacement ribs are spaced to mitigate unwanted obstruction of the tapered sealing surface.

2. The valve seat of claim 1 , wherein the displacement ribs are separate from one another or extend from a common cylindrical base.

3. The valve seat of claim 1 , wherein the tapered sealing surface is cylindrical, and the displacement ribs collectively form a cylindrical shape surrounding the tapered sealing surface.

4. The valve seat of claim 1 , wherein the tapered sealing surface forms a funnel shape that leads to the opening.

5. The valve seat of claim 1 , wherein the opening extends through a port disposed on an opposite side of the rigid wall from the tapered sealing surface and the displacement rib.

6. The valve seat of claim 1 , wherein the tapered sealing surface includes at least one circular sealing ring for compressing against a mating seal member.

7. A disposable medical fluid cassette, comprising: A plurality of valve seats; A pressure feeding unit; a rigid body defining a common well, the common well being in fluid communication with the pumping portion; Equipped with a valve seat of the plurality of valve seats disposed in fluid communication with the pumping portion; At least one valve seat of the plurality of valve seats is disposed within the common well; The plurality of valve seats include A rigid wall; a tapered seal surface extending from the rigid wall, the tapered seal surface surrounding an opening formed in the rigid wall; a plurality of displacement ribs surrounding the tapered seal surface, the displacement ribs being spaced to mitigate unwanted blockage of the tapered seal surface; A disposable medical fluid cassette comprising:

8. A disposable medical fluid cassette as described in claim 7, wherein the plurality of displacement ribs extend from the rigid wall.

9. A disposable medical fluid cassette as described in claim 7, wherein the plurality of displacement ribs extend from an outer edge of the tapered sealing surface.

10. A disposable medical fluid cassette as described in claim 7, wherein the displacement ribs are separated from one another.

11. A disposable medical fluid cassette as described in claim 7, extending from a common cylindrical base.

12. A disposable medical fluid cassette as described in claim 7, wherein the tapered sealing surface is cylindrical and the displacement ribs collectively form a cylindrical shape surrounding the tapered sealing surface.

13. A disposable medical fluid cassette as described in claim 7, wherein the tapered sealing surface forms a funnel shape leading to the opening.

14. A disposable medical fluid cassette as described in claim 7, wherein the opening extends from the tapered sealing surface and the displacement rib through a port located on the opposite side of the rigid wall.

15. The disposable medical fluid cassette of claim 7, wherein the tapered sealing surface includes at least one circular sealing ring for pressing into a mating sealing member.

16. The disposable medical fluid cassette of claim 7, wherein the plurality of valve seats include at least one supply line valve seat and a drain line valve seat.

17. A disposable medical fluid cassette as described in claim 16, wherein the drain line valve seat is positioned relative to the at least one supply line valve seat in the common well such that the drain line valve seat is at a higher position than the at least one supply line valve seat.

18. The disposable medical fluid cassette of claim 7, wherein one of the plurality of valve seats includes a patient line valve seat.

19. A disposable medical fluid cassette as described in claim 7, comprising a flexible sheet sealed to the rigid body, the flexible sheet being bendable to open and close the at least one valve seat.

20. A disposable medical fluid cassette as described in claim 19, wherein the rigid body includes a rigid wall defining the common well, and the flexible sheet is sealed to the rigid wall so as to surround the common well.

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