Peritoneal dialysis system having a capillary type patient line filter

Abstract

The peritoneal dialysis (PD) system (10) includes a PD device (20), a patient line (50) (which may be a dual lumen patient line) extending from the PD device (20), and a filter set (100) in fluid communication with the patient line (50), the filter set (100) including a plurality of hollow fiber membranes (120, e.g., bactericidal grade hollow fiber membranes or sterilized hollow fiber membranes) positioned and arranged such that fresh PD fluid flows through the porous walls of the hollow fiber membranes (120) before exiting the filter set (100).

Description

[Technical field]

[0001] (Priority Claim) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 291,010, filed December 17, 2021, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to medical fluid therapy and, more particularly, to filtration of therapy fluid during dialysis fluid therapy. [Background technology]

[0003] (background) Due to a variety of causes, the renal system fails. Renal failure leads to a variety of physiological abnormalities. It is no longer possible to balance fluids and minerals or to excrete the daily metabolic load. Toxic end products of metabolism such as urea, creatinine, and uric acid can accumulate in the patient's blood and tissues.

[0004] Reduced kidney function, particularly kidney failure, is treated with dialysis, which removes waste products, toxins, and excess fluid from the body that would be removed by normally functioning kidneys. Kidney replacement dialysis treatments are vital for many people because they can be life-saving.

[0005] Hemodialysis (HD), one of the therapies for kidney failure, typically uses diffusion to remove waste products from a patient's blood. A diffusion gradient is created between the blood and an electrolyte solution called the dialysate, or dialysate, through a semi-permeable dialyzer, which induces diffusion.

[0006] Hemofiltration (HF) is another renal replacement therapy that relies on convective transport of toxins from the patient's blood. HF is achieved by adding replacement or substitution fluid to the extracorporeal circuit during the procedure. The replacement fluid, and the fluid that accumulates in the patient during the procedure, are ultrafiltered during the course of HF therapy, providing a convective transport mechanism that is particularly beneficial for the removal of medium and large molecules.

[0007] Hemodiafiltration (HDF) is a treatment that combines convective and diffusive clearance. HDF, like standard hemodialysis, uses dialysate flowing through the dialyzer to provide diffusive clearance, and also provides convective clearance by delivering replacement fluid directly to the extracorporeal circuit.

[0008] Most HD, HF, and HDF procedures are performed in treatment centers. There is currently some movement toward home hemodialysis (HHD) because HHD can be performed daily, which offers therapeutic advantages over in-center hemodialysis, which is typically performed once every 2 to 3 weeks. Studies have shown that patients who receive more frequent treatments have more toxins and waste removed and are less likely to develop fluid overload during dialysis than patients who receive fewer treatments but longer treatment times. Patients who receive more frequent treatments do not experience as many down cycles (fluid and toxin fluctuations) as in-center patients who build up a 2-3 day toxin load before treatment. In some areas, the nearest dialysis center may be many miles away from the patient's home, resulting in door-to-door treatment times that consume a large portion of the patient's day. Even treatments at centers close to the patient's home can consume a large portion of the patient's day. HHD is performed at night or during the day while the patient relaxes, works, or engages in other productive activities.

[0009] Another form of renal failure therapy is Peritoneal Dialysis (PD), in which dialysate, also called dialysate or PD fluid, is infused into the patient's peritoneal cavity via a catheter. The PD fluid contacts the peritoneal membrane in the patient's peritoneal cavity. Waste, toxins, and excess water flow from the patient's bloodstream through the peritoneal capillaries and into the PD fluid by diffusion and osmosis, an osmotic gradient across the peritoneal membrane. An osmotic agent in the PD fluid creates the osmotic gradient. The spent PD fluid is pumped out of the patient, removing the waste, toxins, and excess water. This cycle may be repeated, for example, multiple times.

[0010] There are various types of peritoneal dialysis therapy, including continuous ambulatory peritoneal dialysis (CAPD), automated peritoneal dialysis (APD), tidal peritoneal 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 so that used PD fluid is drained from the peritoneal cavity. The patient then switches the fluid communication so that the patient's catheter is in communication with a bag containing new PD fluid, and new PD fluid is infused into the patient through the catheter. The patient removes the catheter from the bag of new PD fluid, allowing the PD fluid to dwell in the patient's peritoneal cavity, where it transports waste products, toxins, and excess water. After the dwell time, the patient repeats the manual dialysis procedure, for example, four times a day. Manual peritoneal dialysis requires a great deal of time and effort from the patient, and there is ample room for improvement.

[0011] APD is similar to CAPD in that the dialysis treatment includes drain, fill, and dwell cycles. However, these cycles are typically performed automatically by the APD device while the patient sleeps. APD devices free the patient from having to perform the treatment cycles manually and from carrying medical supplies during the day. The APD device is fluidly connected to an implanted catheter, a source or bag of fresh PD fluid, and a fluid drain. The APD device pumps fresh PD fluid from the dialysate source through the catheter and into the patient's peritoneal cavity. The APD device also allows the PD fluid to dwell in the peritoneal cavity, transporting waste, toxins, and excess water. The source can contain several liters of dialysate, including several bags of solution.

[0012] The APD machine pumps spent PD fluid through the catheter and out of the patient's peritoneal cavity. As with manual dialysis treatments, drain, fill, and dwell cycles are repeated several times during dialysis. At the end of an APD treatment, a "final fill" may be performed. The final 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] PD fluid must be sterile or near sterile because it is infused into the patient's abdominal cavity and is therefore considered a drug. Although packaged PD fluid is usually adequately sterilized for the procedure, additional sterilization may be required for connected PD fluid or for PD devices or cyclers that employ disinfection.

[0014] Therefore, there is a need for an effective, low-cost method to provide additional sterilization to fresh PD fluid before it is provided to a patient. Summary of the Invention [Means for solving the problem]

[0015] (summary) The present disclosure provides a peritoneal dialysis (PD) system having a peritoneal dialysis machine or cycler that infuses fresh peritoneal dialysis fluid to a patient via a patient line and removes spent peritoneal dialysis fluid from the patient via a patient line. The patient line can be reusable or disposable, and in either case works with and is in fluid communication with a filter set. If the patient line is reusable, it is connected to the filter set during treatment. If the patient line is disposable, in one embodiment, the filter set is integrated into the disposable patient line. In either configuration, the distal end of the filter set can be connected to a patient transfer set, which is in turn in fluid communication with the patient's indwelling catheter.

[0016] The PD device or cycler may include a durable PD fluid pump or a disposable PD fluid pump. A durable PD fluid pump pumps PD fluid through itself without the use of disposable parts. A disposable PD fluid pump has a pump actuator that actuates disposable fluid-contacting pump parts, such as peristaltic pump tubing or a flexible pump chamber. The PD device or cycler also includes a number of valves. These valves may be flow-through and durable without actuating disposable parts, or disposable valves with valve actuators that actuate disposable fluid-contacting valve parts, such as tubing segments or cassette-based valve seats.

[0017] These pumps and valves are under the automatic control of a control unit provided by the PD device or cycler. In one embodiment, the valves include a fresh PD fluid valve that is opened by the control unit to infuse fresh PD fluid into the patient via the PD fluid pump through the fresh PD fluid lumen of the dual lumen patient line. The valves also include a spent PD fluid valve that is opened by the control unit to pump spent PD fluid out of the patient via the PD fluid pump through the spent PD fluid lumen of the dual lumen patient line. It should be understood that while a single PD fluid pump can be used, dedicated fresh PD fluid pumps and dedicated spent PD fluid pumps can also be used alternately. Also, a single PD fluid pump can include multiple pump chambers to provide a more continuous flow of PD fluid.

[0018] The fresh and used PD fluid lumens may be reusable or disposable. In the case where the fresh and used PD fluid lumens are reusable, they terminate in a connector that connects to the lumen connector of the filter set. The connector is sealed (e.g., ultrasonically welded, heat sealed, solvent bonded) or molded integrally with the body of the filter set. The body is further sealed (e.g., ultrasonically welded, heat sealed, solvent bonded) or molded integrally with a transfer set connector that connects directly to a mating connector of the patient's transfer set or to a mating connector of a short tube disposed between the body and the patient's transfer set. Alternatively, the transfer set connector may simply be a port through which a short tube extends for welding to the port. The body, lumen connector, and transfer set connector may be referred to herein as a filter housing.

[0019] The lumen connector and the body provide a passageway for fresh PD fluid and a passageway for used PD fluid. The passageway for fresh PD fluid leads to a wall, such as a circular wall, that provides or defines a plurality of membrane inlet openings. The membrane inlet openings can be provided in any desired number, such as 6 to 12, such as 8, and can be formed in a circular pattern spaced equiangularly apart. A hollow fiber or capillary membrane is sealed, for example, inside each inlet opening. Such hollow fiber or capillary membranes are, in one embodiment, sterilizing grade hydrophilic membranes or sterilized hydrophilic membranes formed with porous walls with pore sizes of about 0.2 microns through which fresh PD fluid flows for further filtration.

[0020] Fresh PD fluid flows through the fresh PD fluid passageway and inside each of the multiple hollow fiber or capillary membranes. Providing multiple hollow fiber or capillary membranes provides a semipermeable membrane that allows the housing of the filter set to be shorter while still providing the filtration required for multiple patient loadings. A shorter housing is desirable for patient comfort, since the patient typically sleeps close to the filter set during treatment. The hollow fiber or capillary membrane is covered at its distal end, for example, by crimping, welding, gluing, or using a separate cap or a single washer-type cap, so that fresh PD fluid is forced through the pores of the membrane, whereby the fresh PD fluid is ultimately filtered.

[0021] The final filtered fresh PD fluid flows from the hollow fiber or capillary membrane into the central body located between the membranes and from there, either directly or via a short flexible tube, through the transfer set connector into the patient's transfer set. Once the membrane is completely wetted with the fresh PD fluid, the hydrophilicity of the hollow fiber or capillary membrane prevents air movement across the membrane, which serves as a secondary final stage of air removal. However, if necessary, it is conceivable to provide one or more hydrophobic membranes before the hollow fiber or capillary membrane, for example along the path of the fresh PD fluid. The one or more hydrophobic membranes allow air to be vented to the environment before the fresh PD fluid enters the hollow fiber or capillary membrane, improving the performance of the membrane in addition to removing air from the filter set.

[0022] It is further contemplated that an air diversion net may be placed along the path of the fresh PD fluid, e.g., immediately upstream of the hollow fiber or capillary membranes, with mesh openings fine enough to divert air toward one or more hydrophobic membranes when wet, but open enough so as not to significantly impede the flow of fresh PD fluid.

[0023] Spent PD fluid removed through the patient's transfer set enters the filter set housing via the transfer set connector and flows under negative pressure through the central area of ​​the body, the spent PD fluid passageway, and the spent PD fluid lumen back to the device or cycler, where the spent PD fluid is expelled under positive pressure. Because the spent PD fluid positively contacts the outside of the hollow fiber or capillary membrane, but does so tangentially, fibrin, proteins, and other particulates in the patient's effluent are less likely to be trapped or caught by the membrane. The membrane remains available for multiple fill cycles of the procedure before being discarded along with the filter set.

[0024] In light of the disclosure herein, and without limiting the disclosure in any way, the first aspect of the disclosure can be combined with other aspects or portions thereof, where a peritoneal dialysis (PD) system includes a PD device, a patient line extending from the PD device, and a filter set in fluid communication with the patient line, the filter set including a plurality of hollow fiber membranes positioned and arranged such that fresh PD fluid flows through the porous walls of the hollow fiber membranes before exiting the filter set.

[0025] The second aspect of the present disclosure may be combined with other aspects or portions thereof, where the patient line is a dual lumen patient line including a fresh PD fluid lumen disposed in fluid communication with the fresh PD fluid passage of the filter set, and the dual lumen patient line further includes a spent PD fluid lumen disposed in fluid communication with the spent PD fluid passage of the filter set.

[0026] The third aspect of the present disclosure can be combined with the other aspects or portions thereof, where the passageway for spent PD fluid is in fluid communication with a central region located between the hollow fiber membranes, the central region receiving spent PD fluid from a transfer set connector of the filter set.

[0027] The fourth aspect of the present disclosure can be combined with any of the other aspects or portions thereof, where the passageway for fresh PD fluid is in fluid communication with a plurality of inlet openings formed in the wall of the filter set, the inlet openings forming an inlet for fresh PD fluid to the plurality of hollow fiber membranes.

[0028] The fifth aspect of the present disclosure can be combined with other aspects or portions thereof, where the fresh PD fluid passage is at least partially formed through a new PD fluid port and the used PD fluid passage is at least partially formed through a used PD fluid port, where the fresh PD fluid port and the used PD fluid port are part of a lumen side connector configured to connect to a patient line connector of a dual lumen patient line.

[0029] The sixth aspect of the present disclosure can be combined with any of the other aspects or portions thereof, wherein the PD system includes a compressible gasket configured to seal around the fresh PD fluid port and the used PD fluid port between the lumen side connector and the patient line connector.

[0030] The seventh aspect of the present disclosure can be combined with other aspects or parts thereof, where the hollow fiber membrane is closed on one end to pass fresh PD fluid through its porous walls, the ends being closed individually or at least two of the ends being closed via a common structure.

[0031] The eighth aspect of the present disclosure can be combined with any other aspect or portion thereof, where the PD system includes at least one hydrophobic membrane positioned to evacuate air from the fresh PD fluid before it reaches the hollow fiber membranes.

[0032] The ninth aspect of the present disclosure can be combined with any other aspect or portion thereof, wherein the PD system includes at least one net positioned to divert air toward at least one hydrophobic membrane.

[0033] The tenth aspect of the present disclosure may be combined with any of the other aspects or portions thereof, where the filter set is configured to connect directly to a patient transfer set or where the filter set includes flexible tubing configured to connect to a patient transfer set.

[0034] The eleventh aspect of the present disclosure can be combined with any other aspect or part thereof, wherein the filter set is configured such that the spent PD fluid flows tangentially along the outside of the hollow fiber membrane.

[0035] The twelfth aspect of the present disclosure can be combined with any other aspect or part thereof, wherein the filter set is configured such that fresh PD fluid flows from the inside to the outside through the porous walls of the hollow fiber membrane.

[0036] The thirteenth aspect of the present disclosure can be combined with any other aspect or portion thereof, wherein the PD device includes a pressure sensor positioned to sense the pressure of the fresh PD fluid downstream of the hollow fiber membrane during patient filling.

[0037] The fourteenth aspect of the present disclosure can be combined with any other aspect or part thereof, wherein the hollow fiber membrane is a sterilizing grade hollow fiber membrane or a sterilized hollow fiber membrane.

[0038] A fifteenth aspect of the present disclosure can be combined with any of the other aspects or portions thereof, wherein the filter set includes a body holding a plurality of hollow fiber membranes positioned and arranged such that fresh PD fluid flows through the porous walls of the hollow fiber membranes before exiting the body, a lumen connector configured to connect to a patient line, the lumen connector positioned to introduce fresh PD fluid into the body and to receive used PD fluid from the body, and (i) a transfer set connector configured to connect to a patient's transfer set, or (ii) a flexible line configured to connect to a patient's transfer set.

[0039] The sixteenth aspect of the present disclosure can be combined with any of the other aspects or portions thereof, wherein the body includes a passageway for fresh PD fluid in fluid communication with a plurality of inlet openings formed in a wall of the body, the inlet openings forming an inlet for fresh PD fluid to the plurality of hollow fiber membranes.

[0040] The seventeenth aspect of the present disclosure can be combined with other aspects or portions thereof, where the filter set includes a body holding a plurality of capillary membranes positioned and arranged such that new PD fluid flows through the porous walls of the capillary membranes before exiting the body, a lumen connector configured to connect to a patient line, the lumen connector positioned to introduce new PD fluid into the body and receive used PD fluid from the body, and a transfer set connector configured to connect to a patient transfer set, or the filter set includes a flexible line configured to connect to a patient transfer set.

[0041] The eighteenth aspect of the present disclosure may be combined with other aspects or portions thereof, where any of the features, functionality, and alternatives described in connection with one or more of Figures 1 to 6 may be combined with any of the features, functionality, and alternatives described in connection with any other of Figures 1 to 6.

[0042] In light of the above aspects and the description herein, it is an advantage of the present disclosure to provide a filter set that operates in such a dual lumen patient line.

[0043] It is another advantage of the present disclosure to provide a filter set that filters fresh PD fluid and allows used PD fluid to pass without clogging.

[0044] It is a further advantage of the present disclosure to provide a filter set that efficiently spaces filter membranes to reduce size, aiding in patient comfort.

[0045] Other features and advantages are described in and will be apparent from the following detailed description and figures. The features and advantages described herein are not exhaustive, and many additional features and advantages will be apparent to those skilled in the art, particularly in view of the figures and description. Also, a particular embodiment need not have all the advantages enumerated herein, and it is expressly intended that each advantageous embodiment be separately claimed. Furthermore, it should be noted that the terminology used herein has been selected primarily for ease of reading and explanation, and not to limit the scope of the inventive subject matter. [Brief description of the drawings]

[0046] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of a peritoneal dialysis system having a hollow fiber or capillary type patient line filter set in accordance with the present disclosure.

[0047] [Diagram 2] FIG. 2 is a perspective view of one embodiment of a hollow fiber or capillary type patient line filter set according to the present disclosure.

[0048] [Diagram 3] FIG. 3 is a perspective view of the hollow fiber or capillary type patient line filter set of FIG. 2 during patient filling.

[0049] [Figure 4] FIG. 4 is an elevational view of a wall located within the hollow fiber or capillary type patient line filter set of FIG. 2, the wall forming an opening for introducing fresh PD fluid to a plurality of hollow fiber or capillary membranes.

[0050] [Diagram 5] FIG. 5 is a perspective view of the hollow fiber or capillary type patient line filter set of FIG. 2 during drainage from the patient.

[0051] [Figure 6]FIG. 6 is a cross-sectional perspective view showing at least one hydrophobic membrane for venting air and at least one net for diverting air around the at least one hydrophobic membrane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] (Detailed Description) Referring now to the drawings, and in particular to FIG. 1, a peritoneal dialysis (PD) system 10 is shown. The PD system 10 includes a PD machine or cycler 20 that pumps fresh PD fluid to a patient P through a patient line 50 and removes spent PD fluid from the patient P via the patient line 50. The patient line 50 can be reusable or disposable, and in either case operates with and is in fluid communication with a filter set 100. If the patient line 50 is reusable, it is connected to the filter set 100 during a procedure. If the patient line 50 is instead disposable, in one embodiment, the filter set 100 is integrated into the disposable patient line 50. In either configuration, the distal end of the filter set 100 can be connected to a patient transfer set 58, which is in fluid communication with the patient P's indwelling catheter.

[0053] The PD device or cycler 20 can include a housing 22 that provides a durable PD fluid pump 24 that pumps the PD fluid therethrough without the use of disposable parts. Durable pumps that can be used for the PD fluid pump 24 include piston pumps, gear pumps, and centrifugal pumps. Certain durable pumps, such as piston pumps, are inherently accurate, so the device or cycler 20 does not require additional components for volume control. Other durable pumps, such as gear pumps and centrifugal pumps, may not be as accurate, so the device or cycler 20 is provided with a volume control device, such as one or more flow meters (not shown).

[0054] Alternatively, pump 24 may be a disposable type PD fluid pump that includes pump actuators that actuate disposable fluid-contacting pump components, such as peristaltic pump tubing or flexible pump chambers. Disposable PD fluid pumps that can be used for PD fluid pump 24 include rotary or linear peristaltic pump actuators that actuate tubing, pneumatic pump actuators that actuate cassette seats, electromechanical pump actuators that actuate cassette seats, and platen pump actuators that actuate tubing. It should be understood that a single PD fluid pump 24 can be used, but instead, dedicated new and used PD fluid pumps can be used. Additionally, a single PD fluid pump 24 can include multiple pumping chambers for more continuous PD fluid flow.

[0055] The PD device or cycler 20 includes a number of valves 26a, 26b. These may also be flow-through and durable, without operating on disposable parts, or disposable type valves with valve actuators that actuate disposable fluid-contacting valve parts, such as tubing segments or cassette-based valve seats. Durable valves that may be used for the valves 26a, 26b include flow-through solenoid valves. Such valves may be two-way or three-way valves. Disposable valves that may be used for the valves 26a, 26b include solenoid pinch valves that pinch closed flexible tubing, pneumatic valve actuators that actuate cassette seats, and electromechanical valve actuators that actuate cassette seats.

[0056] Apparatus or cycler 20 may include a number of valves, 26a through 26n. For ease of illustration, apparatus or cycler 20 is shown as having fresh PD fluid valve 26a, which is controlled by PD fluid pump 24 to open to pump fresh PD fluid through new PD fluid lumen 52 of dual lumen patient line 50 under positive pressure to patient P. These valves also include spent PD fluid valve 26b, which is controlled by PD fluid pump 24 to open to withdraw spent PD fluid from patient P through used PD fluid lumen 54 of dual lumen patient line 50 under negative pressure.

[0057] The apparatus or cycler 20 in the illustrated embodiment also includes pressure sensors, such as pressure sensors 28a, 28b. Pressure sensor 28a is located immediately downstream of fresh PD fluid valve 26a, while pressure sensor 28b is located immediately upstream of used PD fluid valve 26. Thus, even when fresh PD fluid valve 26a is closed, pressure sensor 28a can sense the pressure in fresh PD fluid lumen 52 of dual lumen patient line 50, while even when used PD fluid valve 26b is closed, pressure sensor 28b can sense the pressure in used PD fluid lumen 54 of dual lumen patient line 50. Additionally, pressure sensor 28a is positioned to sense the pressure of fresh PD fluid upstream of the filter membrane discussed herein during patient fill. Pressure sensor 28b is, perhaps more importantly, positioned to sense the pressure of fresh PD fluid downstream of the filter membrane discussed herein during patient fill.

[0058] The pump 24 and valves 26a, 26b in the illustrated embodiment are automatically controlled by a control unit 40 provided by the device or cycler 20 of the system 10, and outputs from the pressure sensors 28a, 28b (and other sensors) to the control unit 40. The control unit 40 in the illustrated embodiment includes one or more processors 42, one or more memories 44, and a video controller 46. Signals or outputs from the pressure sensors 28a, 28b and other sensors provided by the device or cycler 20, such as one or more temperature sensors 30 and one or more conductivity sensors (not shown), are received, stored, and processed by the control unit 40. Pressure feedback from one or more of the pressure sensors 28a, 28b can be used by the control unit 40 to control the PD fluid pump 24 to pump dialysis fluid at a desired pressure or within safe pressure limits. The pressure limits may be, for example, 0.21 bar (3 psig) of positive pressure into the patient's peritoneal cavity and -0.10 bar (-1.5 psig) of negative pressure from the patient's peritoneal cavity.

[0059] Temperature feedback from one or more temperature sensors 30 is used in control unit 40 to control heater 32, e.g., an in-line heater, to heat fresh PD fluid to a desired temperature, e.g., body temperature or 37° C. In one embodiment, heater 32 is further used to heat a disinfectant fluid, such as fresh PD fluid, to disinfect PD fluid pump 24, valves 26a through 26n, heater 32, and all reusable fluid lines within device or cycler 20 to prepare the device or cycler for the next procedure. The additional filtration discussed herein provides a layer of protection in addition to disinfecting the fluid by heating to ensure that the PD fluid is safe for delivery to patient P.

[0060] The video controller 46 of the control unit 40 is in communication with a user interface 48 of the device or cycler 20. The user interface 48 may include a display screen operated by one or more electromechanical buttons, such as a touch screen and / or membrane switches. The user interface 48 may also include one or more speakers for outputting alerts, warnings, and / or voice guidance commands. The user interface 48 may be provided with the device or cycler 20 as shown in FIG. 1 and / or may be a remote user interface operated by the control unit 40. The control unit 40 may also include a transceiver (not shown) and a wired or wireless connection to a network, e.g., the Internet, for transmitting treatment data to and receiving prescription orders from a doctor or clinician's server, which is in communication with a doctor or clinician's computer.

[0061] 1 and 2, as mentioned above, the fresh PD fluid lumen 52 and the used PD fluid lumen 54 of the dual lumen patient line 50 can also be reusable or disposable. In the case where the dual lumen patient line 50 is reusable, the lumens terminate in a connector 56 that connects to the lumen connector 104 of the filter set 100 and is sealed (e.g., ultrasonically, heat, or solvent bonded) or molded integrally with the filter set body 106. The body 106 is further sealed (e.g., ultrasonically, heat, or solvent bonded) or molded integrally with a transferset connector 108 that connects directly to a mating connector of the patient transferset 58 or to a mating connector of a short length of flexible tubing 110 disposed between the transferset connector 108 and the patient transferset 58.

[0062] 3-5, the transfer set connector 108 can include a port 108a and a threaded shroud 108b for a luer-type connection to a mating connector. Alternatively, the transfer set connector 108 can simply be a port (e.g., port 108a) with a short length of flexible tubing 110 extending thereto for welding thereto. Similarly, if the dual lumen patient line 50 is disposable, the lumen connector 104 can instead simply include ports, e.g., a fresh PD fluid port 104a and a used PD fluid port 104b, with the fresh PD fluid lumen 52 and the used PD fluid lumen 54, respectively, extending thereto for welding thereto. In the illustrated embodiment, the ports 104a and 104b are surrounded by a threaded shroud 104c that can form a luer-type connection with the mating patient line connector 56. A compressible gasket, such as rubber or sponge rubber (not shown), may be formed to seal around ports 104a and 104b between patient line connector 56 and lumen connector 104. Body 106, lumen connector 104, and transfer set connector 108 are sometimes referred to herein as filter housing 102. Filter housing 102 may be made of any one or more plastics, such as polystyrene (PS), polycarbonate (PC), a mixture of polycarbonate and acrylonitrile-butadiene-styrene (PC / ABS), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), a polyester such as polyethylene terephthalate (PET), or polyurethane (PU).

[0063] As shown in FIG. 3, ports 104a, 104b of lumen connector 104 and ports 106a, 106b of body 106 provide a passageway 112 for fresh PD fluid and a passageway 114 for used PD fluid, respectively. The passageway for fresh PD fluid leads to a wall 116, such as a circular wall that provides or defines a number of membrane inlet openings 118 (FIG. 4). The membrane inlet openings 118 can be provided in any desired quantity, for example, 6 to 12, for example, 8, and can be formed in a circular pattern. The openings are equiangularly spaced apart as shown in FIG. 4. A hollow fiber or capillary membrane 120 is sealed, for example, inside each inlet opening 118. Each hollow fiber or capillary membrane 120 can be a sterilizing or sterile grade hydrophilic membrane. The hydrophilic membrane can be formed of porous walls with a pore size of about 0.2 microns, through which the fresh PD fluid flows for further filtration. The hollow fiber or capillary membrane 120 can be made of, for example, polysulfone or polyethersulfone mixed with polyvinylpyrrolidone.

[0064] Fresh PD fluid flows through fresh PD fluid passageway 112 and through the interior of each of the plurality of hollow fiber or capillary membranes 120. Providing multiple hollow fiber or capillary membranes 120 allows the semipermeable membrane, and therefore the housing 102 of filter set 100, to be shorter while still achieving the necessary filtration over multiple patient loadings. A shorter housing 102 is desirable for patient comfort, since the patient typically sleeps close to filter set 100 during treatment. The hollow fiber or capillary membranes 120 are covered at their distal ends, for example by crimping, welding, or gluing, or by using individual caps or a single washer-shaped cap (not shown), to form a seal 122 as shown. Thus, fresh PD fluid is forced to flow through the pores of membrane 120, as shown by the curved arrows in FIG. 3, resulting in the fresh PD fluid finally being filtered.

[0065] The final filtered fresh PD fluid flows from the hollow fiber or capillary membranes 120 into a central region 124 of the body 106 located between the membranes 120 and from there into the patient's transfer set 58 either directly through port 108a of the transfer set connector 108 or via a short flexible tube 110. The hydrophilic nature of the hollow fiber or capillary membranes 120 prevents air from migrating across the membrane when the membrane is fully wetted with the fresh PD fluid, thus acting as a secondary, final stage air removal. If desired, one or more hydrophobic membranes 126, e.g., made from polytetrafluoroethylene (PTFE), may be provided in front of the hollow fiber or capillary membranes 120 (from the perspective of the fresh PD fluid) and, e.g., along the path 112 of the fresh PD fluid, as shown in FIG. One or more hydrophobic membranes 126 can be welded in place via any of the techniques discussed herein, allowing air to be vented to the environment before new PD fluid enters the hollow fiber or capillary membranes 120, as shown by the curved air arrows in Figure 6. This can improve the performance of the membranes 120 in addition to removing air from the filter set 100.

[0066] It is further contemplated that at least one air diversion net 128 may be secured and positioned along the passageway 112 of the fresh PD fluid, e.g., upstream of the hollow fiber or capillary membrane (from the perspective of the fresh PD fluid) and downstream of the hydrophobic membrane 126, by any of the welding techniques described herein. The air diversion net 128 has mesh openings fine enough to divert air toward the one or more hydrophobic membranes 126 when the net is wet, but open enough so as not to significantly impede the flow of fresh PD fluid. The air diversion net 128 may be made of, for example, a medically safe metal or hydrophobic polymer, and may have a pore size ranging from about 0.1 mm to about 0.3 mm.

[0067] Spent PD fluid removed through the patient's transfer set 58 enters the filter set 100 housing 102 via the transfer set connector 108 and flows under negative pressure through the central region 124 of the body 106, the spent PD fluid passageway 114, and the spent PD fluid lumen 54 back to the device or cycler 20. The spent PD fluid is pumped under positive pressure by the device or cycler 20 and drained through the drain line 60 (e.g., a house drain or drain container). Because the spent PD fluid positively contacts the outside of the capillary membrane 120, but does so tangentially, fibrin, proteins, and other particulates in the patient's effluent are less likely to be trapped or caught by the membrane. Thus, the membrane 120 remains available for multiple fill cycles of a procedure before being discarded along with the filter set 100.

[0068] It should be understood that various modifications and variations to the presently preferred embodiments described herein will be apparent to those skilled in the art. It is therefore intended that any or all such modifications and variations be covered by the appended claims. For example, while the flow of fresh PD fluid is shown above as moving from inside to outside through the hollow fiber or capillary membrane 120, it is contemplated that the fresh PD fluid could instead flow from outside to inside through the hollow fiber or capillary membrane 120. In this case, the final filtered fresh PD fluid would flow through the interior of the hollow fiber or capillary membrane 120 to a common collection area within the housing 102 before exiting through the transfer set connector 108.

Claims

1. A peritoneal dialysis ("PD") system (10) comprising: a PD device (20); a patient line (50) extending from the PD device (20); a filter set (100) in fluid communication with the patient line (50); Equipped with The filter set (100) includes a plurality of hollow fiber membranes (120), which are positioned and arranged such that new PD fluid flows through the porous walls of the hollow fiber membranes (120) into a central region (124) located between the plurality of hollow fiber membranes (120) before exiting the filter set (100), and a spent PD fluid passage (114) is in fluid communication with the central region (124), which receives spent PD fluid from a transfer set connector (108) of the filter set (100).

2. 2. The PD system of claim 1, wherein the patient line is a dual-lumen patient line including a lumen for new PD fluid disposed in fluid communication with a passageway for new PD fluid of the filter set, and the dual-lumen patient line further includes a lumen for used PD fluid disposed in fluid communication with a passageway for used PD fluid of the filter set.

3. 3. The PD system of claim 2, wherein the passageway for the new PD fluid is in fluid communication with a plurality of inlet openings formed in a wall of the filter set, the inlet openings providing an inlet for the new PD fluid to the plurality of hollow fiber membranes.

4. 4. The PD system (10) of claim 2 or 3, wherein the new PD fluid passage (112) is formed at least in part through a new PD fluid port (104a), the used PD fluid passage (114) is formed at least in part through a used PD fluid port (104b), and the new PD fluid port and the used PD fluid port (104a, 104b) are part of a lumen-side connector (104) configured to connect to a patient line connector (56) of the dual-lumen patient line (50).

5. 5. The PD system (10) of claim 4, comprising a compressible gasket configured to seal around the new PD fluid port and the used PD fluid port (104a, 104b) between the lumen side connector (104) and the patient line connector (56).

6. 4. The PD system (10) of claim 1, wherein the hollow fiber membranes (120) are closed on one end to pass fresh PD fluid through their porous walls, the ends being closed individually or at least two of the ends being closed via a common structure.

7. 4. The PD system (10) of claim 1, further comprising at least one hydrophobic membrane (126) positioned to expel air from the fresh PD fluid before it reaches the hollow fiber membranes (120).

8. The PD system (10) of claim 7, comprising at least one net (128) positioned to divert air toward the at least one hydrophobic membrane (126).

9. The PD system (10) of any one of claims 1 to 3, wherein the filter set (100) is configured to connect directly to a patient's transfer set, or the filter set (100) includes flexible tubing (110) configured to connect to the patient's transfer set.

10. The PD system (10) of any one of claims 1 to 3, wherein the filter set (100) is configured so that the spent PD liquid flows tangentially along the outside of the hollow fiber membrane (120).

11. The PD system (10) of any one of claims 1 to 3, wherein the filter set (100) is configured so that fresh PD liquid flows from the inside to the outside through the porous walls of the hollow fiber membranes (120).

12. 4. The PD system (10) of claim 1, wherein the PD device (20) includes a pressure sensor (28b) positioned to sense the pressure of fresh PD fluid downstream of the hollow fiber membrane (120) during patient filling.

13. The PD system (10) of any one of claims 1 to 3, wherein the plurality of hollow fiber membranes (120) are sterilizing grade hollow fiber membranes or sterilized hollow fiber membranes.

14. A filter set (100) for a PD system, comprising: a body (106) holding a plurality of hollow fiber membranes (120), the plurality of hollow fiber membranes (120) being positioned and arranged such that new PD fluid flows through porous walls of the hollow fiber membranes (120) into a central region (124) located between the plurality of hollow fiber membranes (120) before exiting the body (106); a lumen-side connector (104) configured to connect to a patient line, the lumen-side connector (104) positioned to introduce fresh PD fluid into the body (106) and receive spent PD fluid from the body (106); a transfer set connector (108) configured to connect to a patient transfer set; Equipped with The transfer set connector (108) is configured to connect to the patient's transfer set, the spent PD fluid passage (114) is in fluid communication with the central region (124), and the central region (124) receives spent PD fluid from the transfer set connector (108) of the filter set (100).

15. 15. The filter set (100) of claim 14, wherein the body (106) includes a passage (112) for fresh PD fluid in fluid communication with a plurality of inlet openings (118) formed in a wall (116) of the body (106), the inlet openings (118) forming inlets for fresh PD fluid to the plurality of hollow fiber membranes (120).

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