System for ultrafiltration of blood

Abstract

A blood ultrafiltration system includes a blood filter (12) having first and second compartments (12a, 12b) separated by a semi-permeable membrane (12c). A blood input line (10a) and a blood output line (10b) are connected in fluid communication with the first compartment (12a). An effluent line (10c) is connected in fluid communication with the second compartment (12b). A peristaltic pump (14) is arranged to repeatedly engage with first and second line segments. In a first arrangement, the first line segment is part of the blood input line (10a) or the blood output line (10b), and the second line segment is part of the effluent line (10c). In a second arrangement, the first line segment is part of the blood input line (10a), and the second line segment is part of the blood output line (10b). The system is operable by the peristaltic pump (14) to pump blood through the blood filter (12) and control extraction of ultrafiltrate in the blood filter (12).

Description

Technical Field

[0001] This disclosure relates to the field of medical treatment, and more particularly to the removal of excess fluid (e.g., water from blood) from human or animal objects, also known as ultrafiltration. Background Technology

[0002] Ultrafiltration (UF) encompasses a variety of membrane filtration technologies, in which hydrostatic pressure forces the liquid against a semi-permeable membrane.

[0003] In blood processing, UF typically refers to the process of removing water from plasma. Blood passes through the blood side of a blood filter, creating a pressure gradient across a semipermeable membrane. This pressure gradient forces fluid through the membrane's pores. These pores filter electrolytes and small to medium-sized molecules from the plasma. Compared to plasma, the ultrafiltrate exiting the filter pores lacks plasma proteins and the cellular components of plasma.

[0004] Fluid overload is a common problem in patients with permanent kidney failure (also known as chronic kidney disease (CKD)). Chronic kidney disease can progress to end-stage renal failure (CKD5), at which point patients must undergo dialysis or a kidney transplant to survive. It has been reported that fluid overload is the primary problem in more than 20% of CKD5 patients.

[0005] Even if a CKD patient has not reached end-stage renal failure, dialysis may be initiated to address fluid excess. However, it is generally desirable to postpone dialysis for as long as possible. Furthermore, for patient convenience and to reduce treatment costs, it is preferred to initiate dialysis with peritoneal dialysis (PD) rather than hemodialysis (HD). However, in CKD patients with significant fluid excess, the UF volume of PD may not be sufficiently high. Additionally, CKD patients undergoing PD may be forced to switch to HD because the UF volume of PD may decrease over time. Another common problem is that CKD patients undergoing HD may find it difficult to achieve and / or maintain a given fluid status through a regular treatment schedule (e.g., 2-3 treatment sessions per week), leading to significant fluctuations in fluid status between treatment sessions and increasing the risk of dialysis complications (e.g., hypotension).

[0006] Therefore, there is a general need for a simple and cost-effective system for removing excess fluid from human or animal subjects as an alternative to or supplement to dialysis therapy. Such a system could be used to extend the time required to initiate dialysis for CKD patients, postpone the time when CKD patients need to switch from PD to HD, and improve fluid balance in CKD patients between and at the start of treatment.

[0007] This system can also be used to treat patients with cardiorenal syndrome (CRS), hepatorenal syndrome (HRS), lung disease, and other functional impairments that cause fluid overload. For example, patients with congestive heart failure (CHF) are frequently hospitalized due to fluid overload.

[0008] WO2004 / 026364 discloses an ultrafiltration device suitable for wearing on a part of a patient's body. The device includes a blood filter, a blood inlet tube leading from a first blood vessel of the patient to the blood filter, and a blood outlet tube leading from the blood filter to a second blood vessel of the patient. A blood pump forces the patient's blood through the blood filter. Through a customized design of the blood filter and downstream flow resistance, transmembrane pressure is generated within the blood filter, causing excess fluid to separate from the blood and flow into a discharge bag connected to a filtrate outlet on the blood filter. A similar device is disclosed in US2004 / 0054315, which also proposes positioning a dedicated UF pump between the filtrate outlet and the discharge bag, and operating the UF pump to extract excess fluid from the blood filter, thereby achieving more precise control of the UF rate.

[0009] US2006 / 0122552 discloses an ultrafiltration device including a blood path extending through a blood filter and comprising a first blood pump and a second blood pump located upstream and downstream of the blood filter, respectively. A third pump is arranged on a conduit extending from a filtrate outlet on the blood filter to a discharge bag. The pumps are controlled such that the pumping rate of the first blood pump is equal to the sum of the pumping rates of the second blood pump and the UF pump.

[0010] Peristaltic pumps are typically used to pump blood and other fluids in systems used for dialysis treatment and in the aforementioned ultrafiltration devices. A peristaltic pump is a volumetric pump that includes a movable actuator operated to intermittently engage and compress a flexible tubing portion, forcing fluid within that portion to move along it. Depending on the actuator configuration, peristaltic pumps can be classified as linear or rotary pumps. The advantages of peristaltic pumps include avoidance of fluid-actuator contact, low maintenance requirements, ease of cleaning, inherent backflow prevention, and a known stroke volume. However, peristaltic pumps are relatively expensive and add weight. Summary of the Invention

[0011] The object of this invention is to overcome, at least in part, one or more limitations of the prior art.

[0012] In view of the above, one objective is to provide a simple and cost-effective ultrafiltration system.

[0013] Another objective is to provide an ultrafiltration system that can operate at a well-defined ultrafiltration rate.

[0014] Another objective is to provide a lightweight and low-complexity ultrafiltration system.

[0015] One or more of these objectives, and other objectives that may emerge from the following description, are achieved at least in part by the system for ultrafiltration of blood, disposable articles, and methods for configuring the system for ultrafiltration of blood according to the independent claims, embodiments of which are defined by the dependent claims.

[0016] A first aspect of this disclosure is a system for ultrafiltration of blood. The system includes: a blood filter defining an internal chamber and including a semi-permeable membrane arranged to divide the internal chamber into a first compartment and a second compartment; a blood inlet line and a blood outlet line, respectively connected to the blood filter in fluid communication with the first compartment; an effluent line connected to the blood filter in fluid communication with the second compartment; and a peristaltic pump arranged to repeatedly engage with the first and second line segments and configured according to either the first or second segment arrangement. The first segment arrangement includes: the first line segment being part of either the blood inlet or blood outlet line and the second line segment being part of the effluent line. The second segment arrangement includes: the first line segment being part of the blood inlet line and the second line segment being part of the blood outlet line.

[0017] In some embodiments, the first pipeline section and the second pipeline section are configured to generate a first fluid flow in the first pipeline section and a second fluid flow in the second pipeline section when the peristaltic pump is operated to repeatedly engage the first pipeline section and the second pipeline section, and the first pipeline section and the second pipeline section are configured to generate the second fluid flow as a predetermined proportion of the first fluid flow.

[0018] In some embodiments, the peristaltic pump is configured according to the arrangement of the first section, and if the first pipeline section is part of a blood inlet pipeline, the predetermined ratio is about 0.01-0.25, or if the first pipeline section is part of a blood outlet pipeline, the predetermined ratio is about 0.01-0.33.

[0019] In some embodiments, the peristaltic pump is configured according to the second segment arrangement, and the predetermined ratio is approximately 0.75-0.99.

[0020] In some embodiments, the first pipeline segment and the second pipeline segment are configured to generate a first fluid flow in the blood inlet line toward the blood filter or a second fluid flow in the blood outlet line away from the blood filter when the peristaltic pump is configured according to the arrangement of the first segment and the peristaltic pump is operated to repeatedly engage the first pipeline segment and the second pipeline segment.

[0021] In some embodiments, the first pipeline segment and the second pipeline segment are configured to generate a first fluid flow toward the blood filter in the blood inlet pipeline and a second fluid flow away from the blood filter in the blood outlet pipeline when the peristaltic pump is configured according to the second segment arrangement and the peristaltic pump is operated to repeatedly engage the first pipeline segment and the second pipeline segment.

[0022] In some embodiments, a first pipeline section and a second pipeline section define corresponding internal fluid passages, wherein the size of the internal fluid passage of the first pipeline section is determined to provide a larger stroke volume than the internal fluid passage of the second pipeline section when engaged by a peristaltic pump.

[0023] In some embodiments, the internal fluid passage of the first pipeline section has a larger cross-sectional area than the internal passage of the second pipeline section.

[0024] In some embodiments, the peristaltic pump is configured according to a first segment arrangement, and if the first pipeline segment is part of a blood inlet pipeline, the cross-sectional area of ​​the internal fluid passage of the first pipeline segment is 4-100 times the cross-sectional area of ​​the internal fluid passage of the second pipeline segment, and if the first pipeline segment is part of a blood outlet pipeline, the cross-sectional area of ​​the internal fluid passage of the first pipeline segment is 3-100 times the cross-sectional area of ​​the internal fluid passage of the second pipeline segment.

[0025] In some embodiments, the peristaltic pump is configured according to a second section arrangement, and the cross-sectional area of ​​the internal fluid passage of the first pipeline section is 1.01-1.33 times the cross-sectional area of ​​the internal fluid passage of the second pipeline section.

[0026] In some embodiments, the peristaltic pump includes a pump head configured to receive a first pipeline segment and a second pipeline segment, wherein the pump head includes a movable actuator arranged to simultaneously engage and compress the first pipeline segment and the second pipeline segment.

[0027] In some embodiments, the peristaltic pump is a peristaltic roller pump or a peristaltic finger pump.

[0028] In some embodiments, the system further includes a valve disposed in or on the effluent line and operable to selectively restrict the effluent line.

[0029] In some embodiments, the peristaltic pump is configured according to a first section arrangement, and a valve is arranged in or on the effluent line between the blood filter and the peristaltic pump.

[0030] In some embodiments, the system further includes a control device connected to operate the peristaltic pump and selectively operate a valve during operation of the peristaltic pump to pump a preset amount of fluid through the effluent line over a predetermined time period.

[0031] In some embodiments, the blood inlet and blood outlet lines include corresponding access devices for fluid connection to the vascular system of a human or animal object.

[0032] A second aspect of this disclosure is a disposable item used in the system of the first aspect. The disposable item includes a first pipeline section and a second pipeline section, wherein the first and second pipeline sections define respective internal fluid passages, and wherein the dimensions of the internal fluid passages of the first pipeline section are determined to provide a larger stroke volume than the internal fluid passages of the second pipeline section upon engagement by a peristaltic pump. In some embodiments, the first and second pipeline sections are formed as units.

[0033] A third aspect of this disclosure is a method of configuring a system for ultrafiltration of blood. The method includes: providing a peristaltic pump configured to repeatedly engage with a first line segment and a second line segment; providing a blood filtration apparatus comprising: a blood filter defining an internal chamber and including a semi-permeable membrane arranged to divide the internal chamber into a first compartment and a second compartment; a blood inlet line and a blood outlet line for connection to the blood filter in fluid communication with the first compartment; and an effluent line for connection to the blood filter in fluid communication with the second compartment; and arranging the first and second line segments in the peristaltic pump according to a first segment arrangement or a second segment arrangement, wherein the first segment arrangement includes: the first line segment being part of the blood inlet line or the blood outlet line and the second line segment being part of the effluent line, and wherein the second segment arrangement includes: the first line segment being part of the blood inlet line and the second line segment being part of the blood outlet line.

[0034] Other objects, features, embodiments, aspects and technical effects will become apparent from the following detailed description, the appended claims and the accompanying drawings. Attached Figure Description

[0035] Embodiments will now be described herein by way of example only, with reference to the accompanying schematic diagrams.

[0036] Figure 1 This is a block diagram of the ultrafiltration system according to the first embodiment.

[0037] Figure 2 This is a front view of an example pump head of a rotary peristaltic pump used according to an embodiment.

[0038] Figure 3A The pump head is without a backstop. Figure 2 The side view taken from direction 3A in the middle. Figure 3B It is a cross-sectional view of the paired pipeline sections of a peristaltic pump, and Figure 3C yes Figure 3B A cross-sectional view of the pipeline section arranged in the pump head.

[0039] Figures 4A to 4B This is a block diagram of an ultrafiltration system according to the second and third embodiments.

[0040] Figure 5A Corresponding to Figure 3A And is Figure 4B A side view of the pump head in the second embodiment, while Figure 5B yes Figure 5A A cross-sectional view of the pipeline section arranged in the pump head.

[0041] Figure 6 This is a front view of another example of the pump head of a rotary peristaltic pump used according to an embodiment.

[0042] Figures 7A to 7B This is a top view of a pipeline section arranged in a peristaltic pump according to an embodiment.

[0043] Figure 8 This is a flowchart of a method for configuring an ultrafiltration system according to an embodiment. Detailed Implementation

[0044] Embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments. In fact, the subject matter of this disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements. The same reference numerals throughout indicate the same elements.

[0045] Additionally, it will be understood that, where possible, any advantages, features, functions, apparatus and / or operational aspects of any embodiment described and / or contemplated herein may be included in any other embodiment described and / or contemplated herein, and / or vice versa. Furthermore, where possible, unless expressly stated otherwise, any term expressed in the singular form herein is intended to also include the plural form and / or vice versa. As used herein, “at least one” shall mean “one or more”, and these phrases are intended to be interchangeable. Thus, the terms “a” and / or “an” shall mean “at least one” or “one or more”, even though the phrases “one or more” or “at least one” are used herein. As used herein, unless the context requires otherwise due to explicit language or necessary meaning, the word “comprising” or variations such as “including” or “containing” are used in an inclusive sense, i.e., specifying the presence of the stated feature in the various embodiments but not excluding the presence or addition of other features.

[0046] It should also be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish elements from one another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] As used herein, "peristaltic pump" has its general meaning and refers to a pumping device that operates to pump fluid through a flexible tube supported on a fixed frame or bracket by repeatedly engaging an actuator with the flexible tube. Ideally, this engagement causes the flexible tube to be fully compressed ("closed") against the bracket. Positive displacement pumping action is generated by moving the positioning of the engagement position along the flexible tube. Peristaltic pumps can be subdivided into two main types: rotary or roller type and linear or inline type. In the rotary type, the actuator includes a roller that engages with the flexible tube and moves in an arc along the flexible tube on the bracket. In the linear type, the actuator engages the flexible tube at right angles to the flow direction through the flexible tube. The actuator may include multiple compression elements (typically active) that engage the flexible tube in a defined sequence to produce pumping action.

[0048] As used herein, "pump head" has its general meaning and refers to a portion of a peristaltic pump that includes a bracket and actuator, and may also include one or more motors for driving the actuator. The pump head can be configured to allow flexible tubing to be mounted in proper alignment with the bracket and actuator. Alternatively, the flexible tubing can be (semi-)permanently mounted in the pump head and has inlet and outlet connectors for connection to external piping.

[0049] As used herein, “ultrafiltration” (UF) has its general meaning and refers to the process of removing a predominantly water-containing fluid from plasma without significantly altering the concentration of small solutes (molecules up to 20,000-30,000 Daltons), thus resulting in a concentration of small solutes in the ultrafiltrate that is substantially the same as that in the plasma. As used in this disclosure, ultrafiltration is performed alone and not concurrently with dialysis. This type of ultrafiltration is sometimes referred to as “isolated ultrafiltration.”

[0050] For the sake of brevity and / or clarity, other well-known functions or constructions may not be described in detail. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0051] The embodiments described herein relate to a system for removing excess fluid from human or animal subjects. The excess fluid is commonly referred to in the art as “filtrate” or “ultrafiltrate,” and such a system will be referred to hereinafter as an “ultrafiltration system.” The embodiments are based on the insight that the number of pumps in an ultrafiltration system can be reduced by using a peristaltic pump configured as a “dual-channel pump.” Such peristaltic pumps are commercially available and are also referred to as “dual-chamber pumps” or “two-chamber pumps.” This type of peristaltic pump includes an actuator configured to simultaneously engage one or more tubular elements defining two internal channels. According to the embodiments, by cleverly installing such a peristaltic pump, an ultrafiltration system with few components can be provided, potentially reducing cost, weight, and / or complexity. The embodiments are illustrated below with reference to a rotary peristaltic pump, but the same applies to other peristaltic pumps.

[0052] Figure 1 An ultrafiltration system 1 according to a first embodiment is shown. System 1 is configured to be connected to the vascular system of a subject 100, which may be a human (as shown) or an animal. The blood circulation path is defined by a first blood line 10a, a blood compartment 12a of a blood filter 12, and a second blood line 10b. The blood circulation path is configured to be connected to the vascular access of the subject 100 via access devices 11a, 11b at the ends of the first blood line 10a and the second blood line 10b. The vascular access can be of any known type, including but not limited to fistulas, grafts, Scribner-shunts, or peripheral veins at any site of the subject 100's body. Correspondingly, the respective access devices 11a, 11b can be of any known type, including but not limited to cannulas, needles, catheters, etc. The blood filter 12 can be any type of blood filtration device (also referred to as a "blood filtration device") suitable for ultrafiltration, such as a coil dialyzer, a parallel plate dialyzer, a hollow fiber dialyzer, etc. Filter 12 includes a housing containing a semi-permeable membrane 12c (in Figure 1 (Schematally represented by dashed lines). Membrane 12c is arranged to divide the internal chamber of the housing into a blood compartment 12a and an ultrafiltrate compartment 12b. In the example shown, the housing includes a first connector 13a and a second connector 13b, the ends of which are connected to the first connector 13a and the second connector 13b to establish fluid communication through the blood compartment 12a. The corresponding blood lines 10a, 10b may include flexible conduits defining internal fluid passages.

[0053] System 1 also includes an effluent line 10c, which may further include a flexible conduit defining an internal fluid passage and connecting at one end to a connector 13c on filter 12, the connector 13c being in fluid communication with ultrafiltrate compartment 12b. At its other end, the effluent line 10c connects to a container or vessel 16 (as shown) or a discharge tube. As shown, a valve 17 may be arranged in or on the effluent line 10c. The valve 17 may be configured to be operable as an on / off valve to open and close the effluent line 10c, or as a flow-limiting valve to change the flow resistance through the effluent line 10c. In one example, the valve 17 is a pinch valve or clamp arranged to engage the outside of the effluent line 10c.

[0054] System 1 also includes a dual-channel peristaltic pump 14, which is arranged to engage a section of the first blood line 10a and a section of the effluent line 10c.

[0055] It should be understood that Figure 1 This is illustrative, and system 1 may include any number of additional devices typically included in an ultrafiltration or dialysis system. For example, such as Figure 1 As shown, the second blood line 10b may include an infusion chamber 15 configured to prevent gas (e.g., air) from being pumped back to object 100 along with the blood. Other examples include an air detector (not shown) and a blood leak detector (not shown), the air detector being disposed in or on the second blood line 10b between the infusion chamber 15 and the access device 11b, and the blood leak detector being disposed in or on the effluent line 10c. System 1 may also include one or more pressure sensors (not shown) for monitoring the pressure in one or more of the lines 10a, 10b, and 10c.

[0056] System 1 also includes an electronic control unit (“controller”) 20 configured to generate one or more control signals Ci for operable components of the system. For example, a first control signal may be generated for operating pump 14, and a second control signal may be generated for operating valve 17. Controller 20 may also receive and process sensor signals Si from one or more sensors in system 1, for example, to implement safety functions for detecting system faults and / or used in generating control signals Ci.

[0057] During operation, when system 1 is connected to object 100 and pump 14 is in an active state, such as Figure 1 As indicated by the circular arrows, blood is drawn from object 100, pumped through the blood circulation path, and returned to object 100. The operation of pump 14 draws blood from object 100 along the first blood line 10a and drives the blood through the blood compartment 12a of filter 12 and along the second blood line 10b. Therefore, in operation, the first blood line 10a is the input line for supplying blood from object 100 to filter 12, while the second blood line 10b is the blood output line for returning blood to object 100. Since the effluent line 10c is also arranged in pump 14, the operation of pump 14 also draws ultrafiltrate from ultrafiltrate compartment 12b into effluent line 10c. Figure 1 The ultrafiltrate (in gray) is driven into container 16. As explained above, the ultrafiltrate is a liquid primarily composed of water, which is driven through membrane 12c by the pressure gradient between blood compartment 12a and ultrafiltrate compartment 12b. The pressure gradient is generated by the operation of pump 14. Figure 1 In this context, Qa represents the blood flow velocity obtained in the first blood line 10a, Qb represents the blood flow velocity obtained in the second blood line 10b, and Qc represents the ultrafiltrate flow velocity (“ultrafiltration rate”) obtained in the effluent line 10c. Assuming an incompressible fluid, then Qc = Qa - Qb. Therefore, Qc needs to be less than Qa, even though both flow velocities are generated by the same pump 14. In one embodiment, further described below with reference to FIG3, Qc is set to a predetermined proportion F of Qa by the configuration of the line sections 10a', 10c', where F = Qc / Qa.

[0058] Figure 2 It shows Figure 1 An example of the dual-channel peristaltic pump 14 in System 1. Specifically, Figure 2This is a front view of the pump head of the peristaltic pump. The pump 14 is rotary, and the pump head 140 includes a fixed frame 141 and concentrically arranged rotors. The fixed frame 141 defines curved support surfaces for two line sections 10a' and 10c'. Line sections 10a' and 10c' are mounted to extend parallel to the curved support surfaces. Line sections 10a' and 10c' are flexible tubing portions and are part of or connected to the first blood line 10a and the effluent line 10c, respectively. In some implementations, line sections 10a' and 10c' may be structurally different from other parts of the first blood line 10a and the effluent line 10c. For example, line sections 10a' and 10c' may be reinforced and / or made of thicker and / or stronger materials to withstand engagement forces from the pump 14 over time. In the example shown, the rotor includes two rollers 142, 144, which are rotatably arranged on corresponding arms 143, 145, which are fixedly arranged on a central axle 146. Rollers 142, 144 are also referred to as shoes, wipers, or lobes. A drive shaft 147 is fixedly attached to and connected to the axle for rotation by an electric motor (not shown). As the rotor rotates, portions of the line sections 10a', 10c' are compressed by the corresponding rollers 142, 144, thereby being clamped and closed (“closed”), allowing fluid to be driven along the corresponding line sections 10a', 10c'. Furthermore, as the corresponding line sections 10a', 10c' open to their natural state (“recovery” or “springback”) after the rollers 142, 144 have passed, fluid flow is introduced into pump 14. The fluid volume propelled through the corresponding pipeline sections by the respective rollers 142, 144 is referred to in the art as the "stroke volume". The rotor of pump 14 can carry more than two rollers 142, 144. When the corresponding pipeline sections 10a', 10c' are closed, the roller pair can trap a certain volume of fluid, which is conveyed toward the pump outlet as the rollers 142, 144 rotate along the curved support surface of frame 141.

[0059] Figure 3A It is pump head 140 in Figure 2 The side view at section 3A shows the pipeline sections 10a' and 10c' removed, and the roller 142. The roller 142 rotates in the direction of the arrow in a pressing manner against the pipeline sections 10a' and 10c'. As shown by the protrusions (enlarged for illustrative purposes) on the corresponding pipeline sections 10a' and 10c', the roller 142 pushes fluid along the pipeline sections 10a' and 10c' in front of the contact line CL between the roller 142 and the frame (not shown).

[0060] Turning Figure 3BThe image is in Figure 3A The cross-sectional view taken at section 3B shows that pipeline sections 10a' and 10c' define internal fluid channels of different sizes. Specifically, the cross-sectional area A of pipeline section 10a' is larger than the cross-sectional area A' of pipeline section 10c'. The aforementioned ratio F can be obtained through simple adaptation of pipeline sections 10a' and 10c without requiring adaptation of the pump 14 itself. Theoretically, the aforementioned ratio F is given by the reciprocal of the area ratio A / A'. In practice, other factors may modify this relationship between ratio F and area ratio A / A' to some extent, such as the degree of blockage generated by the pump, the compliance of pipeline sections 10a', 10c' and / or pipelines 10a, 10c, the fluid pressure in pipelines 10a, 10c, etc. Despite these factors, ratio F also essentially corresponds to area ratio A / A'. Currently, it is believed that ratio F should be approximately 0.01-0.25, depending on the implementation method and desired performance of ultrafiltration system 1. This will approximately correspond to an area ratio A / A' in the range of 4-100.

[0061] To facilitate the installation of pipeline sections 10a' and 10c' within the pump head 140, pipeline sections 10a' and 10c' can be formed as units, for example, through... Figure 3B The web portion 10d' shown is joined together, or through other merging of pipeline sections 10a', 10c'. In one example, pipeline sections 10a', 10c' are compressed into a single component.

[0062] The outer diameters of pipeline sections 10a' and 10c' can differ significantly to accommodate area ratios. When pipeline sections 10a' and 10c' are installed in the pump head, the difference in outer diameter will result in a height difference between pipeline sections 10a' and 10c' on one or both sides. Figure 3B In this context, the height difference on one side is represented by ΔD. It is recognized that the height difference can negatively impact the operation of pump 14, for example, by causing rollers 142, 144 to engage suboptimally with one or both of pipeline sections 10a', 10c' relative to frame 141. Such suboptimal engagement can lead to increased wear or inadequate closure. In one embodiment, as... Figure 3C As shown, for a single pipeline segment pair, frame 141 is provided with a support surface that matches the height difference between the pipeline segments 10a' and 10c' on the side facing frame 141. Figure 3CFigure 3 is a cross-sectional view taken across the extent of pipeline sections 10a' and 10c' when they are installed in the pump head 140. It shows that the supporting surfaces on the frame 141 are stepped in their transverse direction, so the imaginary line between the center points of pipeline sections 10a' and 10c' is substantially parallel to the axis of rotation RA of the roller 142. As can be understood from Figure 3, the axis of rotation RA is defined by the attachment of the roller 142 to the arm 143. The outer periphery of the roller 142 is correspondingly stepped, and defines a first peripheral engagement surface 142a and a second peripheral engagement surface 142b for engagement with pipeline sections 10c' and 10a', respectively, wherein the radius of the first engagement surface 142a is smaller than the radius of the second engagement surface 142b.

[0063] Blood lines 10a, 10b and effluent line 10c can be configured as a single-use group, which are connected to object 100 and installed in an ultrafiltration machine including pump 14 and controller 20 and optionally container 16. Such a single-use group is commonly referred to in the art as a "line group". The single-use group may also include filter 12. Lines 10a, 10b, 10c and filter 12 can be configured as separate components interconnected prior to installation, or can be delivered as pre-assembled units. Line segments 10a', 10c' can also be part of such a single-use group. It is conceivable to provide a series of groups for the operator of the ultrafiltration machine to select, wherein the corresponding group is configured to produce a specific proportion F. If line segments 10a', 10c' are separate components for connection to lines 10a, 10c, then line segments 10a', 10c' can be configured as separate single-use groups.

[0064] Figure 4A An ultrafiltration system 1 according to a second embodiment is shown, which differs from the first embodiment in the arrangement of the pump 14. Figure 4A In this configuration, pump 14 is arranged to connect a section of the second blood line 10b and a section of the effluent line 10c. For Figure 4A For a description of the components, refer to the description of the first embodiment.

[0065] During operation, when system 1 is connected to object 100 and pump 14 is in an active state, such as Figure 4A As indicated by the circular arrows, blood is drawn from object 100, pumped through the blood circulation path, and returned to object 100. Similar to the first embodiment, the first blood line 10a is an input line for supplying blood from object 100 to filter 12, while the second blood line 10b is a blood output line for returning blood to object 100. Operation of pump 14 also draws ultrafiltrate from ultrafiltrate compartment 12b into effluent line 10c and drives the ultrafiltrate into container 16. Like in... Figure 1 In this context, Qc = Qa - Qb, where the relationship between Qb and Qc can be configured through pipeline section settings. (See reference) Figures 3A to 3C The examples presented also apply to Figure 4A The embodiment is shown below. To achieve the desired ratio F = Qc / Qa, the area ratio A / A' should be approximately 1 / F-1, where A' is the cross-sectional area of ​​pipeline segment 10c' and A is the cross-sectional area of ​​the pipeline segment on the second blood pipeline 10b. For example, to achieve a ratio F = Qc / Qa in the range of 0.01-0.25, which corresponds to a ratio Qc / Qb in the range of 0.01-0.33, the area ratio A / A' should be approximately in the range of 3-99.

[0066] Figure 4B An ultrafiltration system 1 according to a third embodiment is shown, which differs from the first and second embodiments in the arrangement of the pump 14. Figure 4B In this configuration, pump 14 is arranged to engage a section of the first blood line 10a and a section of the second blood line 10b. Figure 4A For a description of the components, refer to the description of the first embodiment.

[0067] During operation, when system 1 is connected to object 100 and pump 14 is in an active state, such as Figure 4B As indicated by the circular arrows, blood is drawn from object 100, pumped through the blood circulation path, and returned to object 100. As in the first embodiment, the first blood line 10a is an input line for supplying blood from object 100 to filter 12, while the second blood line 10b is a blood output line for returning blood to object 100. Pump 14 generates a flow rate Qa in the first blood line 10a and a flow rate Qb in the second blood line 10b. If Qa > Qb, a pressure gradient is generated on membrane 12c, resulting in an ultrafiltration rate Qc = Qa - Qb. The relationship between Qa and Qb can be configured through the arrangement of the line sections in pump 14. Figure 5A Corresponding to Figure 3A And it is cut off in the same direction toward pump 14. Figure 5A In the diagram, pipeline sections 10a' and 10b' are portions of the first blood pipeline 10a and the second blood pipeline 10b, respectively. The protrusions on the corresponding pipeline sections 10a' and 10b' illustrate how the roller 142 pushes fluid along the pipeline sections 10a' and 10b' in front of the contact line CL. Figure 5B Is Figure 5AThe cross-sectional view taken at section 5B shows that the cross-sectional area A of pipeline section 10a' is greater than the cross-sectional area A' of pipeline section 10b'. To achieve the desired ratio F = Qc / Qa, the area ratio A / A' should be approximately 1 / (1-F). For example, to achieve a ratio F = Qc / Qa in the range of 0.01-0.25, which corresponds to a ratio Qb / Qa in the range of 0.75-0.99, the area ratio A / A' should be approximately in the range of 1.01-1.33. Pipeline sections 10a' and 10b' can be as follows: Figure 3B The combination facilitates installation, as illustrated by the example of web portion 10d'. Figure 3B Compared to the examples in the previous embodiment, the pipeline sections have more similar outer diameters, which reduces the risk of suboptimal engagement between rollers 142, 144 and pipeline sections 10a', 10b'. However, this can also be achieved in the third embodiment if desired. Figure 3C The modifications shown.

[0068] Figure 6 Alternative configurations for the dual-channel peristaltic pump 14 in the first, second, or third embodiments are shown. The pump 14 is rotary, and the pump head 140 includes a fixed frame 141 defining two curved support surfaces, one for a pipeline segment. The pipeline segments are mounted to extend along the respective support surfaces. In the example shown, pipeline segments 10a', 10c' (see...) Figure 1 It is installed in the pump head 140. The pump head 140 includes... Figure 2 The rotors in this example have a similar structure and are concentrically arranged. (And...) Figure 2 Compared to pump 14, the corresponding rollers 142 and 144 engage only one of the pipeline sections 10a' and 10c' at a time. Figure 6 The pump structure in the middle has the advantage of physically separating the pipeline sections, which can promote consistent engagement between rollers 142, 144 and pipeline sections 10a', 10c', even if the outer diameters of pipeline sections 10a', 10c' are different.

[0069] It can be noted that the aforementioned example of the area ratio between pipeline sections assumes that the pipeline sections have a substantially uniform cross-sectional area along their extent. The embodiments are not limited thereto. Figure 7A This is a cross-sectional view of two pipeline sections 10a' and 10b' arranged to extend in parallel within the pump head 140. In the example shown, the inner diameter of pipeline section 10b' increases linearly from the contact line CLI at the beginning of the roller engagement to the contact line CLT at the end of the roller engagement. Figure 7BAnother example is shown, in which the inner diameter of line segment 10b' gradually increases along line segment 10b' between CLI and CLT. The flow rate generated by the pump in the respective line segments 10a', 10b' and therefore in the respective blood lines 10a, 10b is a function of the fluid volume between CLI and CLT, and thus a function of the total volume of the internal passage from CLI to CLT. Typically, in all embodiments described herein, the size of the internal passage of one of the line segments in pump 14 is determined to provide a larger stroke volume than the internal fluid passage of the other line segment in pump 14.

[0070] exist Figure 1 and Figures 4A to 4B In the example shown, valve 17 on the effluent line can be selectively operated by controller 20 to restrict the effluent line 10c while pump 14 is operated to pump fluid into system 1. This restriction allows the instantaneous ultrafiltration rate to be temporarily and intermittently modified to deviate from the proportion F defined by the line segment. For example, valve 17 is intermittently closed. Controller 21 can operate valve 17 to obtain a preset effective ultrafiltration rate, which represents the amount of fluid to be pumped through effluent line 10c during a predetermined time period. If it is necessary to temporarily stop ultrafiltration, controller 21 can also close valve 17. In this case, it is advantageous to keep pump 14 running to avoid blood stagnation in the blood line (which could lead to clotting blockage). In the first and second embodiments, valve 17 can be arranged between filter 12 and pump 14 ( Figure 1 and Figure 4A This will ensure negative fluid pressure in the effluent line 10c downstream of valve 17, which minimizes the risk of leakage.

[0071] Figure 8 This is a flowchart of a method 800 for configuring an ultrafiltration system 1 according to any embodiment described herein. In step 801, a dual-channel peristaltic pump 14 is provided, for example, as part of an ultrafiltration machine. In step 802, a blood filtration device is provided, for example, in the form of one or more disposable sets as described above. Thus, the blood filtration device may include blood lines 10a, 10b, effluent line 10c, and a filter 12. Line segments may be integrated into two of the lines 10a, 10b, 10c, or configured to be attached to the lines 10a, 10b, 10c. In step 803, according to a first, second, or third embodiment, the line segments are installed in the pump 14 and in fluid communication with the two lines 10a, 10b, 10c.

[0072] The ultrafiltration system 1 described herein is suitable for mobile applications due to its potential for light weight, low cost, and low complexity. In mobile applications, system 1 is worn by subject 100 or otherwise carried. However, system 1 is equally suitable for stationary applications, such as at home, in a dialysis clinic, or in a hospital. Furthermore, system 1 can be operated continuously or intermittently to ultrafilter the subject's blood according to any known ultrafiltration therapy, including but not limited to acute intermittent ultrafiltration and slow continuous ultrafiltration (SCUF)

[0073] The invention has been described above primarily with reference to several embodiments. However, as will be readily understood by those skilled in the art, other embodiments besides those disclosed above are also possible within the scope and spirit of the invention, which are defined and limited only by the appended claims.

Claims

1. A system for ultrafiltration of blood, comprising: A blood filter (12) defining an internal chamber and including a semi-permeable membrane (12c) arranged to divide the internal chamber into a first compartment (12a) and a second compartment (12b). A blood inlet line (10a) and a blood outlet line (10b) are respectively connected to the blood filter (12) and are in fluid communication with the first compartment (12a). An effluent line (10c) is connected to the blood filter (12) and is in fluid communication with the second compartment (12b); and A peristaltic pump (14) is arranged to repeatedly engage with a first pipeline section and a second pipeline section and configured according to either a first section arrangement or a second section arrangement, wherein the first section arrangement includes: the first pipeline section being part of the blood inlet pipeline (10a) or the blood outlet pipeline (10b) and the second pipeline section being part of the effluent pipeline (10c), and wherein the second section arrangement includes: the first pipeline section being part of the blood inlet pipeline (10a) and the second pipeline section being part of the blood outlet pipeline (10b). When the peristaltic pump (14) is operated to repeatedly engage the first pipeline section and the second pipeline section, it generates a flow rate in the effluent line (10c) equal to the difference between the flow rate in the blood inlet line (10a) and the flow rate in the blood outlet line (10b), and wherein the flow rate in the effluent line (10c) is driven by a pressure gradient between the first compartment (12a) and the second compartment (12b) to drive the flow rate of ultrafiltrate through the membrane (12c), the pressure gradient being generated by the operation of the peristaltic pump (14).

2. The system according to claim 1, wherein, The first pipeline section and the second pipeline section are configured to generate a first fluid flow in the first pipeline section and a second fluid flow in the second pipeline section when the peristaltic pump (14) is operated to repeatedly engage the first pipeline section and the second pipeline section, wherein the first pipeline section and the second pipeline section are configured to generate the second fluid flow as a predetermined proportion of the first fluid flow.

3. The system according to claim 2, wherein, The peristaltic pump (14) is configured according to the first section arrangement, and the predetermined ratio is 0.01-0.25 if the first pipeline section is part of the blood inlet pipeline (10a), or 0.01-0.33 if the first pipeline section is part of the blood outlet pipeline (10b).

4. The system according to claim 2 or 3, wherein, The peristaltic pump (14) is configured according to the second section arrangement, and the predetermined ratio is 0.75-0.

99.

5. The system according to any one of claims 2-4, wherein, The first and second pipeline sections are configured such that, when the peristaltic pump (14) is configured according to the first section arrangement and operated to repeatedly engage the first and second pipeline sections, a first fluid flow is generated in the blood inlet line (10a) toward the blood filter (12) or in the blood outlet line (10b) away from the blood filter (12), and a second fluid flow is generated in the effluent line (10c) away from the blood filter (12).

6. The system according to any one of claims 2-4, wherein, The first and second pipeline sections are configured such that, when the peristaltic pump (14) is configured according to the second section arrangement and operated to repeatedly engage the first and second pipeline sections, a first fluid flow toward the blood filter (12) is generated in the blood inlet line (10a), and a second fluid flow away from the blood filter (12) is generated in the blood outlet line (10b).

7. The system according to any one of the preceding claims, wherein, The first pipeline section and the second pipeline section define corresponding internal fluid passages, wherein the size of the internal fluid passage of the first pipeline section is determined to provide a larger stroke volume than the internal fluid passage of the second pipeline section when engaged by the peristaltic pump (14).

8. The system according to claim 7, wherein, The internal fluid passage of the first pipeline section has a larger cross-sectional area than the internal passage of the second pipeline section.

9. The system according to any one of the preceding claims, wherein, The peristaltic pump (14) includes a pump head (140) configured to receive the first pipeline section and the second pipeline section, wherein the pump head (140) includes movable actuators (142-146) arranged to simultaneously engage and compress the first pipeline section and the second pipeline section.

10. The system according to any one of the preceding claims further includes a valve (17) disposed in or on the effluent line (10c) and operable to selectively restrict the effluent line (10c).

11. The system according to claim 10, wherein, The peristaltic pump (14) is configured according to the first section arrangement, and wherein the valve (17) is arranged in or on the effluent line (10c) between the blood filter (12) and the peristaltic pump (14).

12. The system according to claim 10 or 11 further includes a control device (20) connected to operate the peristaltic pump (14) and selectively operate the valve (17) during operation of the peristaltic pump to pump a preset amount of fluid through the effluent line (10c) for a predetermined time period.

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