Peritoneal dialysis system including a patient line filter having a tubular membrane - Patents.com

Abstract

The peritoneal dialysis (PD) system (10) includes a PD machine (20), a patient line (50) extending from the PD machine (20), and a filter set (100), the filter set (100) including a filter housing (102) having a tubular filter membrane (120, e.g., a sterile grade filter membrane or a sterilized filter membrane) positioned and arranged to filter fresh PD fluid flowing radially across the tubular filter membrane (120), and a transfer set side port (106p) positioned and arranged to receive (i) filtered fresh PD fluid during patient fill and (ii) spent PD fluid during patient drain.

Description

[Technical field]

[0001] (Priority Claim) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 291,029, 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 performed automatically by the APD device, usually 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. If the fresh and used PD fluid lumens are reusable, they terminate in a patient line connector that connects with the lumen connector of the filter set. In one embodiment, the lumen connector includes a fresh PD fluid port for communicating with the fresh PD fluid lumen of the dual lumen patient line and a used PD fluid port for communicating with the used PD fluid lumen of the dual lumen patient line. The lumen connector may include a threaded shroud for threading onto mating threads of the patient line connector. In one embodiment, the mating ports of the patient line connector are sealed to the fresh and used PD fluid ports of the lumen connector by threading the patient line into the lumen connector of the connector, for example, via one or more gaskets.

[0019] The passageway for the fresh PD fluid extends from the fresh PD fluid port of the lumen-side connector through a wall, e.g., circular, that forms part of the filter housing. This wall forms a fresh PD fluid inlet to the tubular filter membrane. The fresh PD fluid, in one embodiment, flows through the fresh PD fluid inlet and into the interior of the tubular filter membrane. The fresh PD fluid is forced through the tubular filter membrane for further filtration by pressurizing the interior of the tubular filter membrane. The tubular filter membrane can be a bactericidal grade hydrophilic membrane or a sterilized hydrophilic membrane. The membrane can be formed with porous walls with pore sizes of about 0.2 microns through which the fresh PD fluid flows for further filtration. The tubular filter membrane is sized to be small enough to avoid discomfort to the patient, who is likely to be asleep during the procedure, but to provide sufficient filtration over multiple patient loadings.

[0020] The final filtered fresh PD fluid flows from the interior of the tubular filter membrane into a filtered fluid compartment, e.g., cylindrical, located between the exterior surface of the tubular filter membrane and the interior of the filter housing. The final filtered fresh PD fluid flows into the patient's transferset through a transferset port (common to both fresh and used PD fluid), either directly or via a short flexible tube located between the filter housing and the patient's transferset. The transferset port can be surrounded by a threaded shroud, which forms a transferset connector. The transferset connector is connected directly to a mating connector on the patient's transferset or to a mating connector of a short tube located between the filter housing and the patient's transferset. If no shroud is provided, the transferset connector can instead simply be a transferset port, with a short tube extending over or into it for ultrasonic welding, heat sealing, and / or solvent bonding (e.g., with a solvent) to the port.

[0021] Spent PD fluid removed from the patient under negative pressure through the patient's transfer set enters the filter housing through the transfer set port of the transfer set connector. The spent PD fluid enters the filtered fluid compartment in the filter housing and moves out of the filtered fluid compartment through a spent PD fluid outlet formed in the wall of the filter housing. The spent PD fluid exiting the PD fluid outlet flows through a spent PD fluid passageway that extends to a spent PD fluid port of the lumen connector. The spent PD fluid exiting the spent PD fluid port of the lumen connector flows through the spent PD fluid lumen of the dual lumen patient line by a PD fluid pump under negative pressure and back to the PD device or cycler. The PD device or cycler pumps and drains the spent PD fluid under positive pressure.

[0022] Because the spent PD fluid directly contacts the outer surface of the tubular filter membrane, but does so tangentially, fibrin, proteins, and other particulates in the patient's effluent are less likely to become trapped or stuck to the membrane, and thus the filter membrane remains usable for multiple filling cycles of PD treatments before being discarded along with the filter set.

[0023] Furthermore, the hydrophilic nature of the filter membrane prevents air from migrating across it when the membrane is fully wetted with new PD fluid, thus acting as a secondary, end-stage air removal. However, if desired, it is contemplated to provide one or more hydrophobic membranes upstream of the filter membrane (from the perspective of the new PD fluid), e.g., along the circular side bounding the tubular filter membrane. The one or more hydrophobic membranes can vent air to the environment, e.g., via one or more vents in one or more walls adjacent to the one or more hydrophobic membranes, before the new PD fluid flows through the filter membrane.

[0024] In light of the disclosure herein, the first aspect of the disclosure can be combined with any other aspect or portion thereof described herein without limiting the disclosure in any way, wherein the peritoneal dialysis (PD) system includes a PD device, a patient line extending from the PD device, and a filter set, the filter set having a filter housing with a tubular filter membrane positioned and arranged to filter fresh PD fluid flowing radially across the tubular filter membrane, and a transfer set side port positioned and arranged to receive (i) filtered fresh PD fluid during patient fill and (ii) spent PD fluid during patient drain.

[0025] The second aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, 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, the dual lumen patient line further including a spent PD fluid lumen disposed in fluid communication with the spent PD fluid passage of the filter set, the fresh PD fluid passage positioned and arranged to deliver fresh PD fluid to the tubular filter membrane.

[0026] The third aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the fresh PD fluid passageway is positioned and arranged to deliver fresh PD fluid to the interior of the tubular filter membrane.

[0027] The fourth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the PD system includes a wall forming part of a filter housing, the wall including an inlet to a tubular filter membrane, the inlet being in fluid communication with a passage for fresh PD fluid.

[0028] The fifth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the wall includes an outlet through which spent PD fluid flows into the spent PD fluid passageway.

[0029] The sixth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the filter housing is configured to allow spent PD fluid to flow across the tubular filter membrane to an outlet.

[0030] The seventh aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein the filter housing is configured to allow fresh filtered PD fluid to flow to a filtered fluid compartment, the filtered fluid compartment being in fluid communication with a transfer set port and a spent PD fluid outlet, and wherein the PD device is configured to close the spent PD fluid valve during patient fill to encourage fresh filtered PD fluid to flow to the transfer set port.

[0031] The eighth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the PD device is configured to close the fresh PD fluid valve during drainage from the patient, urging spent PD fluid to flow to the spent PD fluid outlet.

[0032] The ninth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the PD system includes at least one hydrophobic membrane positioned and arranged to evacuate air from the fresh PD fluid upstream of the tubular filter membrane.

[0033] The tenth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein at least one hydrophobic membrane is positioned at at least one end of a tubular filter membrane.

[0034] The eleventh aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein the filter set is configured such that fresh PD fluid is filtered from the inside to the outside of the tubular filter membrane.

[0035] A twelfth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein the filter set includes a lumen side connector and a gasket for sealing between the lumen side connector and a patient line connector.

[0036] The thirteenth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, 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.

[0037] A fourteenth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, where the PD device includes a pressure sensor positioned and arranged to sense the pressure of fresh filtered PD fluid downstream of the filter membrane during patient filling.

[0038] The fifteenth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein the tubular filter membrane is a sterilizing grade filter membrane or a sterilized filter membrane.

[0039] A sixteenth aspect of the present disclosure may be combined with any other aspect or portion thereof described herein, wherein a filter set for connection to a patient line includes a filter housing including a tubular filter membrane positioned and arranged to filter fresh PD fluid flowing radially across the tubular filter membrane, a filtered fluid compartment for receiving fresh PD fluid filtered from the tubular filter membrane, and a transfer set side port positioned and arranged to receive (i) fresh PD fluid filtered from the filtered fluid compartment during patient fill and (ii) spent PD fluid during patient drain.

[0040] The seventeenth aspect may be combined with any other aspect or portion thereof described herein, where the features, functions, and alternatives described in connection with any one or more of Figures 1-3 of the present disclosure may be combined with any of the features, functions, and alternatives described in connection with any other of Figures 1-3.

[0041] In light of the above aspects and disclosure herein, it is an advantage of the present disclosure to provide a filter set that operates with a dual lumen patient line.

[0042] 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.

[0043] A further advantage of the present disclosure is to provide a filter set whose filtration capacity can be easily adjusted by changing the size of the filter membrane sheets.

[0044] Yet another advantage of the present disclosure is providing a filter set that is easily manufactured and has a drainage feature that functions regardless of filter orientation.

[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 including a patient line filter set having a tubular filter membrane of the present disclosure.

[0047] [Diagram 2] FIG. 2 is a perspective view of the patient line filter set of FIG. 1 during patient fill.

[0048] [Diagram 3] 3 is a perspective view of the patient line filter set of FIG. 1 during drainage from the patient. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] (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.

[0050] 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).

[0051] 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.

[0052] The PD device or cycler 20 also includes a number of valves 26a, 26b, 26m, 26n. These may also be flow-through and durable, without actuation by disposable components, or disposable type valves with valve actuators that actuate disposable fluid-contacting valve components such as tubing segments or cassette-based valve seats. Durable valves that may be used for the valves 26a, 26b, 26m, 26n 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, 26m, 26n include solenoid pinch valves that pinch closed flexible tubing, pneumatic valve actuators that actuate cassette seats, and electromechanical valve actuators that actuate cassette seats.

[0053] 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 fresh 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 spent PD fluid lumen 54 of dual lumen patient line 50 under negative pressure. One or more supply valves 26m are provided to allow selective access to one or more PD fluid sources, while valve 26n is provided to allow selective access to a drain via exhaust line 60, such as a drain container or house drain.

[0054] The device 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, and pressure sensor 28b is located immediately upstream of used PD fluid valve 26b. 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 filling. Pressure sensor 28b is positioned, perhaps more importantly, to sense the pressure of fresh PD fluid downstream of the tubular filter membrane during patient filling. Thus, the pressure drop across the tubular filter membrane is taken into account, more accurately reflecting the pressure at which PD fluid is delivered to the patient.

[0055] 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.

[0056] 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.

[0057] 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 PD 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.

[0058] 1-3, as discussed above, the fresh PD fluid lumen 52 and the spent 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 a lumen connector 104 of the filter set 100. In one embodiment, the lumen connector 104 includes a fresh PD fluid port 104a for communicating with the fresh PD fluid lumen 52 of the dual lumen patient line 50 and a used PD fluid port 104b for communicating with the used PD fluid lumen 54 of the dual lumen patient line 50. In the illustrated embodiment, the fresh PD fluid port 104a and the used PD fluid port 104b are surrounded by a shroud 104s of the lumen connector 104, which has threads 104c formed thereon for mating with mating threads of the patient line connector 56. In one embodiment, the mating ports (not shown) of the patient line connector 56 are sealed to the fresh PD fluid port 104a and the used PD fluid port 104b of the lumen connector 104 by threading the patient line connector 56 into the lumen connector 104 via one or more compressible gaskets (not shown), such as, for example, silicone or other suitable rubber gaskets. In the illustrated embodiment, the shroud 104s has a keyed opening 104k formed in the front surface. The patient line connector 56 is formed with a mating key so that the patient line connector can be introduced into the shroud 104s only in the proper orientation to align the new PD fluid lumen 52 with the new PD fluid port 104a and the used PD fluid lumen 54 with the used PD fluid port 104b.

[0059] 2 and 3 show that the fresh PD fluid passageway 108 extends from the fresh PD fluid port 104a of the lumen connector 104 to a first wall 102f that forms part of the filter housing 102. In the illustrated embodiment, the first wall 102f forms or defines a fresh PD fluid inlet 102i into the interior of the tubular filter membrane 120. In the illustrated embodiment, the first wall 102f forms a port 102p that is ultrasonically welded, heat sealed, and / or adhesively sealed (e.g., with a solvent) to a mating port 104p of the lumen connector 104.

[0060] In one embodiment, fresh PD fluid in FIG. 2 flows through fresh PD fluid inlet 102i along fresh PD fluid path 108 during patient filling, as indicated by the flow direction arrows, into the interior of tubular filter membrane 120. Fresh PD fluid is forced to further filter through tubular filter membrane 120 by pressurizing the interior of tubular filter membrane 120. Tubular filter membrane 120 can be a bactericidal grade hydrophilic membrane or a sterilized hydrophilic membrane. This hydrophilic membrane can be formed of porous walls with pore sizes of about 0.2 microns, through which fresh PD fluid flows for further filtration. Tubular filter membrane 120 can be made of polysulfone or polyethersulfone, for example, mixed with polyvinylpyrrolidone. The tubular filter membrane 120 may, for example, be (i) 30 mm to 40 mm in length, such as 35 millimeters (mm); (ii) 8 mm to 22 mm in diameter, such as 10 mm in diameter; and (iii) 10 to 20 square centimeters (cm) in area so as to be small enough to avoid discomfort to the patient, who will likely be asleep during treatment, and to provide sufficient filtration across multiple patient loads. 2 ) surface area.

[0061] The final filtered fresh PD fluid in FIG. 2 flows from the inside across the tubular filter membrane 120 as indicated by the flow direction arrows to a filtered fluid compartment 102c located between the exterior surface of the tubular filter membrane 120 and the inside of the body 102b, e.g., of the cylindrical body, of the filter housing 102. The final filtered fresh PD fluid during patient filling flows through a transferset port 106p (common to both fresh and used PD fluid) to the patient's transferset 58, either directly or via a short flexible tube 112 (FIG. 1) located between the filter housing 102 and the patient's transferset 58. The transferset port 106p can be surrounded by a threaded shroud 106s, which forms the transferset connector 106. The transferset connector 106 is either directly connected to a mating connector of the patient's transferset 58 or is connected to a mating connector of a short tube 112 located between the filter housing 102 and the patient's transferset 58. If the shroud 106s is not provided, the transferset side connector 106 may instead simply include a transferset side port 106p over or into which the short tube 112 extends for sealing with ultrasonic welding, heat sealing, solvent bonding (e.g., solvent). Similarly, if the dual lumen patient line 50 is disposable, the lumen side connector 104 may instead simply include ports, such as a fresh PD fluid port 104a and a used PD fluid port 104b, over or into which the fresh PD fluid lumen 52 and the used PD fluid lumen 54 extend for similar sealing to the respective ports.

[0062] 2 and 3 show that the second wall 102s of the filter housing 102 can be molded along with the body 102b and the transferset connector 106. Here, the filter set 100 can be assembled using three molded pieces: (i) the lumen connector 104, (ii) the first wall 102f, and (iii) the housing 102 / transferset connector 106, such as by ultrasonic welding, heat welding, and / or solvent bonding. The filter set 100 can include a short length of flexible tubing 112, as described herein. Any of the molded pieces may be made from any one or more plastics such as polystyrene (PS), polycarbonate (PC), a mixture of polycarbonate and acrylonitrile-butadiene-styrene (PC / ABS), polyvinyl chloride (PVC), polyesters such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polyurethane (PU). Flexible tube 112 may be made from PVC or non-PVC flexible tubing.

[0063] 1 and 3 show that during drainage from the patient, spent PD fluid withdrawn under negative pressure from the patient P through the transfer set 58 enters the filter housing 102 through the transfer set port 106p of the transfer set connector 106, as indicated by the flow arrows. The spent PD fluid enters the filtered fluid compartment 102c located within the filter housing 102 and travels from the filtered fluid compartment 102c through the spent PD fluid outlet 102o formed in the first wall 102f, as indicated by the flow arrows. The spent PD fluid exiting the PD fluid outlet 102o flows through the spent PD fluid passageway 110, which extends to the spent PD fluid port 104b of the lumen connector 104. The spent PD fluid exiting spent PD fluid port 104b of lumen side connector 104 flows under negative pressure by PD fluid pump 24 through spent PD fluid lumen 54 of dual lumen patient line 50, as indicated by the flow direction arrows, and back to PD device or cycler 20. The spent PD fluid is pumped under positive pressure by PD device or cycler 20 and discharged via discharge line 60.

[0064] Because the spent PD fluid directly contacts the outer surface of the tubular filter membrane 120, but does so tangentially, fibrin, proteins, and other particulates in the patient's waste are less likely to become trapped or stuck to the membrane, and thus the tubular filter membrane 120 remains usable for multiple fill cycles of PD therapy before being discarded along with the filter set 100.

[0065] Additionally, the hydrophilic nature of the tubular filter membrane 120 prevents air from migrating across the membrane when the membrane 120 is fully wetted with new PD fluid, thus acting as a secondary end-stage air removal. However, if desired, it is contemplated to provide one or more hydrophobic membranes 122 upstream of the tubular filter membrane 120 (from the perspective of the new PD fluid), for example along one or more circular sides that bound the tubular filter membrane 120. The one or more hydrophobic membranes 122 may be composed of, for example, polytetrafluoroethylene (PTFE). The one or more hydrophobic membranes 122 in the illustrated embodiment are ultrasonically welded, heat sealed, and / or solvent bonded to cylindrical mounts that extend from one or more of the first and / or second walls 102f, 102s of the filter housing 102. The one or more hydrophobic membranes 122 may allow air to be vented to the environment, e.g., via one or more vent holes 102v in one or more first and / or second walls 102f, 102s adjacent to the one or more hydrophobic membranes 122, before new PD fluid flows through the tubular filter membrane 120.

[0066] 1 and 2, during patient filling, the control unit 40 closes the spent PD fluid valve 26b. Also, during patient filling, the spent PD fluid lumen 54 and the spent PD fluid passage 110 are filled with new PD fluid and / or used PD fluid. As a result, the new filtered PD fluid that enters the filtered fluid compartment 102c through the holes in the tubular filter membrane 120 is effectively prevented from flowing through the PD fluid outlet 102o to the spent PD fluid lumen 54. Thus, new PD fluid is delivered from the filter set 100 to the patient P.

[0067] 1 and 3, during drainage from the patient, fresh PD fluid valve 26a is closed by control unit 40. Also, during drainage from the patient, fresh PD fluid lumen 52, fresh PD fluid passageway 108, and the interior of tubular filter membrane 120 are filled with fresh PD fluid. As a result, spent PD fluid entering filtered fluid compartment 102c from transfer set port 106p is effectively prevented from flowing through the pores of tubular filter membrane 120. Thus, spent PD fluid is pumped from filter set 100 to spent PD fluid lumen 54.

[0068] It should be understood that various modifications and alterations to the presently preferred embodiments described herein will be apparent to those skilled in the art. It is therefore intended that any or all such modifications and alterations may be covered by the appended claims. For example, although the dual lumen patient line 50 is shown to operate with fresh PD fluid ports 104a and spent 104b in the lumen connector 104, the patient line may instead be a single lumen patient line communicating with a single port in the lumen connector 104. Here, check valves may be sealed and oriented in the fresh PD fluid passageway 108 and the spent PD fluid passageway 110 to direct the fresh and spent PD fluids as needed. Additionally, although the fresh PD fluid is described as being filtered through the tubular filter membrane 120 from the inside, the fresh PD fluid may instead be filtered through the tubular filter membrane 120 from the outside.

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) including a filter housing (102) and a transfer set side port (106p); Equipped with the filter housing (102) has a tubular filter membrane (120) positioned and arranged to filter fresh PD fluid flowing radially across the tubular filter membrane (120), and the transfer set side port (106p) positioned and arranged to receive (i) filtered fresh PD fluid during patient fill and (ii) spent PD fluid during patient drain; 1. A PD system (10), wherein the filter housing (102) is configured so that spent PD fluid enters the filtered fluid compartment (102c) and flows across the tubular filter membrane (120) to a spent PD fluid outlet (102o).

2. 2. The PD system of claim 1, wherein the patient line is a dual-lumen patient line including a new PD fluid lumen disposed in fluid communication with a new PD fluid passageway of the filter set, the dual-lumen patient line further including a spent PD fluid lumen disposed in fluid communication with a spent PD fluid passageway of the filter set, the new PD fluid passageway being positioned and arranged to deliver fresh PD fluid to the tubular filter membrane.

3. The PD system (10) of claim 2, wherein the fresh PD fluid passage (108) is positioned and arranged to deliver fresh PD fluid to the interior of the tubular filter membrane (120).

4. 4. The PD system (10) of claim 2 or 3, comprising a wall (102f) forming part of the filter housing (102), the wall (102f) including an inlet (102i) to the tubular filter membrane (120), the inlet (102i) in fluid communication with the new PD fluid passage (108).

5. 5. The PD system of claim 4, wherein the wall portion includes an outlet for the spent PD fluid, and wherein spent PD fluid flows through the outlet for the spent PD fluid to the passageway for the spent PD fluid.

6. 4. The PD system of claim 1, wherein the filter housing is configured to allow fresh filtered PD fluid to flow to the filtered fluid compartment, the filtered fluid compartment being in fluid communication with the transfer set port and the spent PD fluid outlet, and the PD device is configured to close the spent PD fluid valve during patient filling to force the fresh filtered PD fluid to flow to the transfer set port.

7. 7. The PD system of claim 6, wherein the PD device is configured to close the fresh PD fluid valve during drainage from the patient, forcing spent PD fluid to flow through the spent PD fluid outlet.

8. 4. The PD system (10) of claim 1, further comprising at least one hydrophobic membrane (122) positioned and arranged to expel air from the fresh PD fluid upstream of the tubular filter membrane (120).

9. The PD system (10) of claim 8, wherein the at least one hydrophobic membrane (122) is positioned at at least one end of the tubular filter membrane (120).

10. The PD system (10) of any one of claims 1 to 3, wherein the filter set (100) is configured such that fresh PD fluid is thoroughly filtered through the tubular filter membrane (120).

11. The PD system (10) of any one of claims 1 to 3, wherein the filter set (100) includes a lumen side connector (104) and a gasket for sealing between the lumen side connector (104) and a patient line connector (56).

12. 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 (112) configured to connect to the patient's transfer set.

13. The PD system (10) of any one of claims 1 to 3, wherein the PD device (20) includes a pressure sensor (28b) positioned and arranged to sense the pressure of the filtered new PD fluid downstream of the filter membrane (112) during patient filling.

14. The PD system (10) of any one of claims 1 to 3, wherein the tubular filter membrane (120) is a sterilizing grade filter membrane or a sterilized filter membrane.

15. A filter set (100) for connection to a patient line for use in a PD system (10) according to any one of claims 1 to 3, said filter set (100) comprising: a filter housing (102) including a tubular filter membrane (120), the tubular filter membrane (120) positioned and arranged to filter new PD fluid flowing radially across the tubular filter membrane (120); a filtered fluid compartment (102c) for receiving fresh filtered PD from said tubular filter membrane (120); a transfer set-side port (106p) positioned and arranged to receive (i) fresh filtered PD fluid from said filtered fluid compartment (102c) during patient fill, and (ii) spent PD fluid during patient drain; Equipped with The filter set (100) is configured such that the filter housing (102) allows spent PD fluid to enter the filtered fluid compartment (102c) and flow across the tubular filter membrane (120) to a spent PD fluid outlet (102o).

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