Peritoneal dialysis system having a patient line filter - 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) in fluid communication with the patient line (50), the filter set (100) including a filter membrane (120, such as a sterilizing grade or bacterial reducing filter membrane), the filter membrane (120) positioned and arranged such that fresh PD fluid flows through the filter membrane (120) into a filtered fluid compartment (106f), the filtered fluid compartment including an outlet (106t) to a port (106p), the port being in fluid communication with a spent PD fluid tubing (106u), the spent PD fluid tubing positioned and arranged to transport spent PD fluid past the filter membrane (120) without contacting the filter membrane (120). Methods of priming the filter set (100) are also disclosed.

Description

[Technical field]

[0001] (Priority Claim) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 290,855, 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 fluids during dialysis fluid therapy. [Background technology]

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

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

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

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

[0007] Hemodiafiltration ("HDF") is a therapy that combines convective and diffusive clearance. HDF uses dialysis fluid flowing through a dialyzer, similar to standard hemodialysis, to provide diffusive clearance. In addition, substitution solution is provided directly to the extracorporeal circuit to provide convective clearance.

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

[0009] Another type of renal failure therapy is peritoneal dialysis ("PD"), in which dialysis solution, also called dialysis fluid 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 chamber. Waste, toxins and excess water pass from the patient's bloodstream through capillaries in the peritoneal membrane and enter the PD fluid by diffusion and osmosis (i.e., an osmotic gradient occurs across the membrane). An osmotic agent in the PD fluid provides the osmotic gradient. The spent PD fluid is pumped out of the patient, removing the waste, toxins and excess water from the patient. This cycle may be repeated, for example, multiple times.

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

[0011] APD is similar to CAPD in that the dialysis treatment includes drain, fill and dwell cycles. However, APD machines perform the cycles automatically, usually while the patient sleeps. APD machines relieve the patient from having to manually perform the treatment cycles and from having to deliver supplements during the day. APD machines fluidly connect to an implanted catheter, a source or bag of fresh PD fluid, and a fluid drain. The APD machine pumps fresh PD fluid from the dialysis fluid source through the catheter and into the patient's peritoneal chamber. APD machines also allow the PD fluid to dwell in the chamber, allowing the transfer of waste, toxins and excess water to occur. The source may contain multiple liters of dialysis fluid, including several solution bags.

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

[0013] PD fluids need to be sterile or very close to sterile because they are injected into the patient's peritoneal cavity and are therefore considered drugs. Bagged PD fluids are generally adequately sterilized for treatment, but PD fluids made on-line, or PD machines or cyclers that use disinfection, may require additional sterilization.

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

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

[0016] The PD machine or cycler may include a durable PD fluid pump that pumps the PD fluid through the pump itself without the use of disposable components, or a disposable-type PD fluid pump that includes a pump actuator that actuates a disposable, fluid-contacting pumping component, such as a peristaltic pump tubing or a flexible pumping chamber. The PD machine or cycler also includes a number of valves that may be flow-through and durable without operating with 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.

[0017] The pumps and valves are under the automatic control of a control unit provided by the machine or cycler. In one embodiment, the valves include a fresh PD fluid valve that the control unit opens to allow the PD fluid pump to pump fresh PD fluid to the patient through the fresh PD fluid lumen of the dual lumen patient line. The valves also include a spent PD fluid valve that the control unit opens to allow the PD fluid pump to pump spent PD fluid from the patient through the spent PD fluid lumen of the dual lumen patient line. Although a single PD fluid pump may be used, it should be understood that dedicated fresh and spent PD fluid pumps may alternatively be used. The single PD fluid pump may also include multiple pumping chambers for a more continuous flow of PD fluid.

[0018] The fresh and spent PD fluid lumens may again be reusable or disposable. If the fresh and spent PD fluid lumens are reusable, the lumens terminate in connectors that connect to the lumen connectors of the filter set, which may be sealed (e.g., ultrasonically sealed, heat sealed, or solvent bonded) to the body of the filter set or molded with the body of the filter set. The body is then sealed (e.g., ultrasonically sealed, heat sealed, or solvent bonded) to the transfer set connector or molded with the transfer set connector, which connects directly to a mating connector on the patient's transfer set or to a mating connector on a short tube disposed between the body and the patient's transfer set. Alternatively, the transfer set connector may be disposed at the end of a short tube extending from the body. Here, the body includes a transfer set port (e.g., molded with a transfer set port) and a short tube extends into or over the transfer set port for welding to the port. The body, lumen side connector, and transferset side connector or port may be referred to herein as the filter housing.

[0019] The lumen connector and the body form a fresh PD fluid passageway and a spent PD fluid passageway. The fresh PD fluid passageway extends through a fresh PD fluid port in the lumen connector and toward a wall disposed in the body of the filter housing. The wall redirects the fresh PD fluid and causes it to flow over the wall into an outer compartment, which resides over the outside of the flat sheet filter membrane. The fresh PD fluid is pressurized in the outer compartment. The pressurization, particularly while under negative patient drain pressure, forces the fresh PD fluid through the flat sheet filter membrane and into a filtered fluid compartment of the body, which is primarily bounded by the inner surface of the flat sheet filter membrane and a ribbed wall having a series of ribs supporting the flat sheet filter membrane.

[0020] The filter membrane may be a sterilizing or bacterial reducing grade hydrophilic membrane formed with a porous wall having a pore size of about 0.2 microns through which the fresh PD fluid flows for further filtration. The flat sheet filter membrane is sized to provide the necessary filtration required over multiple patient fills of PD therapy.

[0021] Fresh and further filtered PD fluid, in one embodiment, flows from the filtered fluid compartment of the body through an outlet provided in the ribbed wall to the transferset side port, through the transferset side port, through the short tube of the filter set, through the patient's transferset, and into the patient's peritoneal cavity. The short tube extends over the transferset side port and is ultrasonically sealed, heat sealed, or solvent bonded to the transferset side port. The transferset side port extends to an internal spent PD fluid tube present in one embodiment adjacent to the filtered fluid compartment. The spent PD fluid tube may be molded with the main portion of the body. The spent PD fluid tube extends from the transferset side port to a spent PD fluid port provided by the lumen side connector, collectively forming a spent PD fluid passageway. The spent PD fluid port is in sealed fluid communication with the spent PD fluid lumen of the dual lumen patient line during operation.

[0022] The spent PD fluid tube is drawn through the body of the filter housing without the spent PD fluid coming into contact with and potentially clogging the filter membrane. The spent PD fluid tube provides an unobstructed, straight path for the spent PD fluid, which also helps to mitigate pressure losses through the filter set. Although it is fluidically possible for the spent PD fluid to flow into the filtered fluid compartment of the body through the outlets provided in the ribbed wall, negative pressure is applied only from within the spent PD fluid tube, and therefore there is little incentive for the spent PD fluid to flow into the filtered fluid compartment. Similarly, it is fluidically possible for fresh PD fluid to flow back in the opposite direction up the spent PD fluid tube, but the required change of direction makes such a path much more tortuous than simply flowing to the patient through a transfer set side port. Additionally, the spent PD fluid tubing and the spent PD fluid lumen of the dual lumen patient tubing are likely to fill with PD fluid during patient fill, and the spent PD fluid lumen is closed in the PD machine or cycler, thus leaving little or no room for fresh PD fluid to enter the spent PD fluid tubing.

[0023] Optionally, it is conceivable to cover the outlet provided in the ribbed wall with at least one hinged closure flap. The one or more hinges may be one or more living hinges, with the at least one closure flap molded with the ribbed wall along one or more sides of the outlet. The at least one closure flap opens under a positive pressure applied by the freshly filtered PD fluid, allowing the PD fluid to flow from the outlet to the transfer set side port. A flow of the spent PD fluid across the at least one closure flap closes the flap, thereby preventing the spent PD fluid from flowing into the filtered fluid compartment through the outlet provided in the ribbed wall. It is conceivable to form the at least one hinged closure flap such that the flap is biased closed when not under positive pressure from the fresh PD fluid. The at least one hinged closure flap provides the functionality of a one-way valve or a check valve without the need for a separate valve.

[0024] As mentioned above, the ribbed wall that partially forms the filtered fluid compartment of the body is, in one embodiment, provided with a series of ribs that support the flat sheet filter membrane, particularly when placed under negative fluid pressure. In this aspect, the filter membrane can be sized as needed to provide the desired filtration capacity. The ribbed wall is, in one embodiment, co-molded with the spent PD fluid tubing, the lumen side connector, and the transfer set side connector. The flat sheet filter membrane is sealed in place to the inner wall of the body adjacent to the ribbed wall by ultrasonic sealing, heat sealing, or solvent bonding.

[0025] The filter housing body includes a cap that may be formed from the same material as the remainder of the filter housing body. The cap may be ultrasonically sealed, heat sealed, or solvent bonded to an outer portion of the body sidewall. A tongue-and-groove fit may be provided between the cap and the sidewall to center the cap for sealing. The cap forms the outside of the outer compartment into which fresh PD flows before passing through the filter membrane.

[0026] The cap may be formed with one or more vent holes. Each vent hole is covered by a hydrophobic membrane on the inside of the cap, which may be ultrasonically sealed, heat sealed, or solvent bonded to the inner surface of the cap around at least one vent opening. The one or more vent holes and the hydrophobic membrane allow air to be vented to the atmosphere as fresh PD fluid is pressurized in the outer compartment of the body before being filtered through the hydrophilic membrane, which may improve the performance of the membrane in addition to removing air from the filter set. In one embodiment, the cap is provided with one or more protective ribs positioned adjacent to the one or more vent holes. The one or more protective ribs help prevent the one or more vent holes from being covered by the patient, blanket, etc. while the patient is sleeping during PD treatment.

[0027] A gasket, such as a silicone or polyvinyl chloride ("PVC") rubber gasket, may be fitted over and / or into the fresh and used PD fluid ports of the lumen-side connector of the filter housing. The patient line connector may include fresh and used ports that extend into the fresh and used PD fluid ports of the lumen-side connector. The gasket provides a port seal between the mating fresh and used PD fluid ports of the patient line connector and the lumen-side connector.

[0028] The spent PD fluid removed through the patient transfer set passes under negative pressure through the filter set (thus bypassing the filter membrane) via the spent PD fluid tubing, through the spent PD fluid lumen of the dual lumen patient line, and back to the machine or cycler. The machine or cycler pumps the spent PD fluid out under positive pressure. The cycler includes a pressure sensor located along the spent PD fluid side of its internal tubing, which measures the negative pressure applied to the spent PD fluid by the PD fluid pump during patient drain. The same pressure sensor is used to measure the positive pumping pressure (which, if not blocked by at least one closure flap, may be returned to the pressure sensor through the spent PD fluid tubing of the filter set and the spent PD fluid lumen of the patient line) during patient fill, which is desirable since the measured pressure is the pressure of the fresh PD fluid downstream (after filtration) of the filter membrane. Thus, the measured pressure takes into account any pressure drop across the filter membrane, which more accurately reflects the pressure at which the PD fluid is pumped to the patient.

[0029] In a first aspect of the present disclosure, which in light of the disclosure set forth herein is in no way limiting to the present disclosure but which may be combined with any other aspect or portion thereof, a peritoneal dialysis ("PD") system includes a PD machine, a patient line extending from the PD machine, and a filter set in fluid communication with the patient line, the filter set including a filter membrane, the filter membrane positioned and arranged such that fresh PD fluid flows through the filter membrane to a filtered fluid compartment, the filtered fluid compartment including an outlet to a port, the port in fluid communication with a spent PD fluid tube positioned and arranged to transport spent PD fluid past the filter membrane without contacting the filter membrane.

[0030] In a second aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the patient line is a dual lumen patient line including a fresh PD fluid lumen and a spent PD fluid lumen, the spent PD fluid lumen being disposed in fluid communication with the spent PD fluid tube.

[0031] In a third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the filter set includes a fresh PD fluid port for fluid communication with the fresh PD fluid lumen and a spent PD fluid port for fluid communication with the spent PD fluid lumen.

[0032] In a fourth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the used PD fluid tube is in fluid communication with the used PD fluid port.

[0033] In a fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the port extends to a used PD fluid tube.

[0034] In a sixth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the outlet is releasably covered by at least one hinged closure flap.

[0035] In a seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the PD system includes at least one rib located in the filtered fluid compartment to support the filter membrane.

[0036] In an eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter membrane is a flat sheet filter membrane and the filter set includes an outer compartment located on an opposite side of the flat sheet filter membrane from the filtered fluid compartment.

[0037] In a ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter set includes a fresh PD fluid port positioned and arranged to introduce fresh PD fluid into the outer compartment.

[0038] In a tenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter set includes a deflection wall positioned and arranged to deflect fresh PD fluid from the fresh PD fluid port toward the outer compartment.

[0039] In an eleventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter set includes a cap that cooperates with the filter membrane to form an outer compartment.

[0040] In a twelfth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the cap includes at least one vent opening and at least one hydrophobic membrane sealingly covering the at least one vent opening.

[0041] In a thirteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter set is configured to connect directly to a patient transfer set, or the filter set includes a flexible tube configured to connect to a patient transfer set.

[0042] In a fourteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the PD machine includes a pressure sensor positioned and arranged to sense the pressure of fresh PD fluid downstream of the filter membrane during patient fill.

[0043] In a fifteenth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the PD machine is configured to close the spent PD fluid valve during patient fill and force the filtered fresh PD fluid to flow to the port rather than along the spent PD fluid tube.

[0044] In a sixteenth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the PD machine is configured to close the fresh PD fluid valve during patient drain and force the spent PD fluid to flow along the spent PD fluid tube rather than into the filtered fluid compartment.

[0045] In a seventeenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the filter membrane is a sterilizing grade filter membrane or a bacteria reducing filter membrane.

[0046] In an eighteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a filter set includes a port, a filtered fluid compartment including an outlet to the port, a filter membrane positioned and arranged such that fresh PD fluid flows through the filter membrane into the filtered fluid compartment, and a spent PD fluid tube in fluid communication with the port, the spent PD fluid tube positioned and arranged to transport the spent PD fluid past the filter membrane without contacting the filter membrane.

[0047] In a nineteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, there is provided a method of priming a filter set connected to a dual lumen patient line, where during treatment, tubing is located between the filter set and a patient's transfer set, the method including: (i) directing fresh peritoneal dialysis ("PD") fluid to the filter set through a fresh PD fluid lumen of the dual lumen patient line; (ii) forcing the fresh PD fluid through at least one filter membrane of the filter set such that the fresh PD fluid displaces air towards the spent PD fluid lumen of the dual lumen patient line; and drawing spent PD fluid from the patient, through the patient's transfer set, via the tubing, through the spent PD fluid portion of the filter set and into the spent PD fluid lumen of the dual lumen patient line.

[0048] In a twentieth aspect of the present disclosure that may be combined with any other aspect or portion thereof, drawing off spent PD fluid is provided as part of the initial patient drain.

[0049] In a twenty-first aspect of the present disclosure, which may be combined with any other aspect or portion thereof, between forcing fresh PD fluid through the filter membrane and drawing spent PD fluid from the patient, the patient is prompted to connect a tube to the patient's transfer set.

[0050] In a twenty-second aspect of the present disclosure, which may be combined with any other aspect or portion thereof, between forcing fresh PD fluid through the filter membrane and drawing spent PD fluid from the patient, the patient is prompted to open a clamp on the patient's transfer set.

[0051] In a twenty-third aspect of the present disclosure that may be combined with any other aspect or portion thereof, air is primed through at least one vent opening of the filter set while fresh PD fluid is pumped through the fresh PD fluid lumen of the dual lumen patient line.

[0052] In a twenty-fourth aspect of the present disclosure that may be combined with any other aspect or portion thereof, while pumping fresh PD fluid through the fresh PD fluid lumen of the dual lumen patient line, the fresh PD fluid valve is opened and the used PD fluid valve is closed.

[0053] In a twenty-fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spent PD fluid valve is open while forcing fresh PD fluid through the filter membranes of the filter set.

[0054] In a twenty-sixth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spent PD fluid valve is open while drawing spent PD fluid from the patient.

[0055] In a twenty-seventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, a method includes accumulating known volumetric pump strokes to control the amount of fresh PD fluid pumped through a filter membrane.

[0056] In a twenty-eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the method includes sensing a pressure increase upon a transition from (i) sending fresh PD fluid through a fresh PD fluid lumen of a dual lumen patient line to a filter set, to (ii) forcing the fresh PD fluid through at least one filter membrane.

[0057] In a twenty-ninth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spent PD fluid portion of the filter set includes a spent PD fluid tube.

[0058] In a thirtieth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the spent PD fluid drawn from the patient is residual effluent from a previous treatment that is left for the purposes of priming the tubing.

[0059] In a thirty-first aspect of the present disclosure that may be combined with any other aspect or portion thereof, the amount of residual effluent is at least 50 ml.

[0060] In a thirty-second aspect of the present disclosure, which may be used in conjunction with any other aspect or portion thereof, any of the features, functions, and alternatives described in association with any one or more of Figures 1 to 7 may be combined with any of the features, functions, and alternatives described in association with any other of Figures 1 to 7.

[0061] It is therefore an advantage of the present disclosure, in light of the above aspects and the description herein, to provide a filter set that operates with a dual lumen patient line.

[0062] Another advantage of the present disclosure is to provide a filter set that filters fresh PD fluid and allows spent PD fluid to pass through without contacting the filter membrane.

[0063] Yet another advantage of the present disclosure is to provide a filter set that expels air from fresh PD fluid before it is further filtered by the filter set.

[0064] Further features and advantages are described in and will be apparent from the following detailed description and drawings. The features and advantages described herein are not all-inclusive, and in particular many further features and advantages will be apparent to those skilled in the art in view of the drawings and description. Also, any particular embodiment need not have all the advantages listed herein, and it is expressly contemplated to separately claim each advantageous embodiment. Furthermore, it should be noted that the language used in this specification has been selected primarily for ease of reading and description purposes, and is not intended to limit the scope of the subject matter of the present invention. [Brief description of the drawings]

[0065] [Figure 1]FIG. 1 is a schematic diagram of one embodiment of a peritoneal dialysis system having a filter set of the present disclosure.

[0066] [Diagram 2] 1 is a cross-sectional perspective view of one embodiment of a filter housing of a filter set of the present disclosure during patient filling. FIG.

[0067] [Diagram 3] FIG. 2 is a perspective view of one embodiment of an optional lumen-side connector of a filter housing of the filter set of the present disclosure.

[0068] [Figure 4] FIG. 1 is a perspective view highlighting the filtered fluid compartment and associated filter membrane support ribs and used PD fluid tube of one embodiment of a filter set of the present disclosure.

[0069] [Diagram 5] FIG. 1 is a cross-sectional perspective view of one embodiment of a filter housing of a filter set of the present disclosure in a patient drain.

[0070] [Figure 6] FIG. 13 is a cross-sectional perspective view showing one embodiment for providing a hinged closure flap for sealing a used PD fluid tube of a filter housing of a filter set of the present disclosure.

[0071] [Figure 7] FIG. 13 is a cross-sectional perspective view showing another embodiment for providing a hinged closure flap for sealing a used PD fluid tube of a filter housing of a filter set of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] 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 may be reusable or disposable, and in either case operates in conjunction with and is in fluid communication with a filter set 100. If the patient line 50 is reusable, the reusable patient line is connected to the filter set 100 during treatment. If the patient line 50 is instead disposable, in one embodiment, the filter set 100 is merged with or formed with the disposable patient line 50. In either configuration, the distal end of the filter set 100 may be connected to a patient transfer set 58, which is in turn in fluid communication with the patient P's indwelling catheter.

[0073] The PD machine or cycler 20 may include a housing 22 that includes a durable PD fluid pump 24 that pumps the PD fluid through the pump itself without the use of disposable parts. Examples of durable pumps that may 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 precise, such that the machine or cycler 20 does not require additional volume control components. Other durable pumps, such as gear pumps and centrifugal pumps, may not be precise, such that the machine or cycler 20 provides a volume control device, such as one or more flow meters (not shown).

[0074] Alternatively, pump 24 may be a disposable type PD fluid pump, which includes a pump actuator that actuates disposable fluid-contacting pumping components, such as peristaltic pump tubing or flexible pumping chambers. Examples of disposable PD fluid pumps that may 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. While a single PD fluid pump 24 may be used, it should be understood that dedicated fresh and used PD fluid pumps may alternatively be used. A single PD fluid pump 24 may also include multiple pumping chambers for a more continuous PD fluid flow.

[0075] The PD machine or cycler 20 also includes a number of valves 26a, 26b, 26m, 26n, which may similarly be flow-through and durable without operating with disposable components, or may be disposable type valves with valve actuators that actuate disposable fluid-contacting valve components, such as tubing segments or cassette-based valve seats. Examples of 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. Examples of 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.

[0076] The machine or cycler 20 will likely include a number of valves 26a-26n. For ease of illustration, the machine or cycler 20 is shown as having a fresh PD fluid valve 26a that is controlled to open to allow the PD fluid pump 24 to pump fresh PD fluid under positive pressure through the fresh PD fluid lumen 52 of the dual lumen patient line 50 to the patient P. The valves also include a spent PD fluid valve 26b that is controlled to open to allow the PD fluid pump 24 to draw spent PD fluid from the patient P through the spent PD fluid lumen 54 of the dual lumen patient line 50 under negative pressure. The valves also include one or more supply valves 26m that are controlled to open to allow fresh PD fluid to be drawn from one or more fresh PD fluid sources. The valves further include a drain valve 26n that is controlled to allow the spent PD fluid to be sent to a house drain or drain receptacle via a drain line 60.

[0077] The machine or cycler 20 in the illustrated embodiment also includes pressure sensors, such as pressure sensors 28a, 28b. Pressure sensor 28a is positioned immediately downstream of fresh PD fluid valve 26a, and pressure sensor 28b is positioned immediately upstream of spent PD fluid valve 26. Thus, pressure sensor 28a can sense the pressure in the fresh PD fluid lumen 52 of dual lumen patient line 50 even when fresh PD fluid valve 26a is closed, and pressure sensor 28b can sense the pressure in the spent PD fluid lumen 54 of dual lumen patient line 50 even when spent PD fluid valve 26b is closed. Additionally, pressure sensor 28a is positioned to sense the pressure of the fresh PD fluid upstream of a filter membrane 120 described herein during patient fill. Pressure sensor 28b is, perhaps more importantly, positioned to sense the pressure of the fresh PD fluid downstream (post-filtration) of filter membrane 120 during patient fill. Thus, the pressure measured via pressure sensor 28b takes into account any pressure drop across filter membrane 120, which more accurately reflects the pressure at which fresh PD fluid is being delivered to patient P.

[0078] Pump 24 and valves 26a-26n in the illustrated embodiment are under the automated control of a control unit 40 provided by machine or cycler 20 of system 10, to which pressure sensors 28a, 28b (and other sensors) output. Control unit 40 in the illustrated embodiment includes one or more processors 42, one or more memories 44, and a video controller 46. Control unit 40 receives, stores, and processes signals or outputs from pressure sensors 28a, 28b, and other sensors provided by machine or cycler 20, such as one or more temperature sensors 30 and one or more conductivity sensors (not shown). The control unit 40 can use pressure feedback from one or more of the pressure sensors 28a, 28b to control the PD fluid pump 24 to pump dialysis fluid at a desired pressure or within safe pressure limits (e.g., within 0.21 bar (3 psig) of the positive pressure to the patient's peritoneal cavity and within −.10 bar (−1.5 psig) of the negative pressure from the patient's peritoneal cavity).

[0079] The control unit 40 uses temperature feedback from one or more temperature sensors 30 to control a heater 32, such as an in-line heater, to heat the fresh PD fluid to a desired temperature (e.g., body temperature or 37° C.). In one embodiment, the heater 32 is further used to heat a disinfectant fluid, such as fresh PD fluid, to disinfect the PD fluid pump 24, valves 26a-26n, heater 32, and all reusable fluid lines in the machine or cycler 20 to prepare the machine or cycler for the next treatment. The additional filtration discussed herein provides a layer of protection in addition to the heated fluid disinfection to ensure that the PD fluid is safe for delivery to the patient P.

[0080] The video controller 46 of the control unit 40 interfaces with a user interface 48 of the machine or cycler 20, which may include a display screen operated with 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 alarms, warnings, and / or voice guidance commands. The user interface 48 may be provided with the machine or cycler 20 as shown in FIG. 1 and / or may be a remote user interface operating with 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, to transmit treatment data to and receive prescription orders from a physician or clinician server that interacts with a physician or clinician's computer.

[0081] 1 and 2, as already mentioned above, the fresh and used PD fluid lumens 52 and 54 of the dual lumen patient line 50 may again 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 the connector 56 is sealed (e.g., ultrasonically welded, heat sealed, solvent bonded) to or molded with the body 106 of the filter set. The body 106 in the illustrated embodiment is connected to a short (e.g., flexible) tube 108 that extends to a transferset connector 110, which connects directly to a mating connector of the patient's transferset 58. The short, e.g., flexible, tube 108 allows the rigid lumen connector 104 and body 106 to be separated from the rigid transferset connector 110 to aid in patient comfort. Forming the body 106 to include the transferset connector 110 or attaching the transferset connector 110 to the body 106 and then connecting these rigid structures to the patient's rigid transferset 58 can lead to a combined rigid assembly that is uncomfortable and tethered to the patient P. The space also provided by the tubing 108 separates the body 106 from the transferset connector 110, such that only the rigid transferset connector is mechanically connected to the patient's transferset 58. However, in alternative embodiments, the transferset connector 110 can be formed with the body or attached to the body 106.

[0082] The packaged filter set 100 may be provided with removable caps (not shown, assuming the dual lumen patient line 50 is reusable) on both ends of the filter set 100 to maintain sterility after the set has been sterilized, for example via gamma radiation, steam or ethylene oxide. To use the filter set 100, the patient or user removes and discards the caps.

[0083] 2, the lumen side connector 104 may simply include ports, such as fresh and used PD fluid ports 104f and 104u, with the fresh and used PD fluid lumens 52 and 54 extending over or into the PD fluid ports 104f and 104u, respectively, for sealing. If the dual lumen patient line 50 is reusable, the patient line connector 56 may include releasable clamps that releasably clamp (e.g., compress a gasket that interacts between the patient line connector 56 and the PD fluid ports 104f and 104u) to the fresh and used PD fluid ports 104f and 104u. If the dual lumen patient line 50 is disposable, the fresh and used PD fluid lumens 52 and 54 may be ultrasonically sealed, heat sealed, or solvent bonded to the fresh and used PD fluid ports 104f and 104u, respectively.

[0084] 3, in an alternative embodiment, the fresh and used ports 104f and 104u of the lumen side connector 104 are surrounded by a threaded shroud 104s that may form a luer-type connection with the mating patient line connector 56, where the patient line connector 56 is configured to thread into the threaded shroud 104s, causing the patient line connector 56 to compress a gasket (not shown) and seal the mating fresh and used PD fluid ports of the patient line connector 56 to the fresh PD fluid port 104f and used PD fluid port 104u, respectively. The gasket may be fitted over and / or into the fresh and used PD fluid ports 104f and 104u of the lumen side connector 104. The patient line connector 56 may include fresh and used ports that extend into the fresh and used PD fluid ports 104f and 104u of the lumen side connector 104. In one embodiment, the gasket provides a port seal between the mating fresh and spent PD fluid ports of the patient line connector 56 and the lumen side connector 104 .

[0085] The lumen-side connector 104 and the body 106 may be referred to herein as the filter housing 102. The filter housing 102, the transfer set-side connector 110, the cap (not shown), and any other rigid or semi-rigid polymers associated with the filter set 100 may be made of any one or more plastics, such as polystyrene ("PS"), polycarbonate ("PC"), a blend 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"). The compressible gasket 112 may be formed from silicone rubber, PVC, or other similar elastomeric materials, such as styrene-ethylene-butylene-styrene ("SEBS") or isoprene. The flexible tube 108 may be made of PVC, or a non-PVC material, such as polybutadiene ("PBD") or PP.

[0086] 2 and 5 show that the cap 106c is ultrasonically sealed, heat sealed, or solvent bonded to the sidewall 106s of the body 106 to complete the body. Before sealing the cap 106c to the sidewall 106s of the body 106, the flat sheet filter membrane 120 is ultrasonically sealed, heat sealed, or solvent bonded to the inner portion of the sidewall 106s of the body 106 at its periphery. The flat sheet filter membrane 120 is made of an embodiment of a hydrophilic material that may have a pore size of about 0.2 microns, and the fresh PD fluid flows through this membrane for further filtration. The filter membrane 120 may be made of polysulfone or polyethersulfone mixed with polyvinylpyrrolidone, for example. The filter membrane 120 may be a sterilizing grade filter membrane or a bacteria reduction filter membrane.

[0087] 2 and 5 further show that the cap 106c may be provided with vent openings 106v, which allow air to escape from the fresh PD fluid before being filtered through the filter membrane 120. To maintain sterility within the body 106, one or more hydrophobic membranes 122a, 122b, etc. are ultrasonically sealed, heat sealed, or solvent bonded to the inner surface of the cap 106 around its / their periphery to surround and cover its / their respective vent openings 106v. The hydrophobic membranes 122a, 122b, etc. may be made, for example, from polytetrafluoroethylene ("PTFE"). Although the cap 106c is shown as being provided with multiple sets of vent openings 106v and corresponding hydrophobic membranes 122a, 122b, the cap 106c may be provided with only a single set of vent openings and corresponding hydrophobic membranes.

[0088] The one or more hydrophobic membranes 122a, 122b, etc. allow air to be vented to atmosphere as fresh PD fluid is pressurized in the outer compartment 106o located below the cap 106c before being filtered through the hydrophilic filter membrane 120, which may improve the performance of the filter membrane 120 in addition to removing air from the filter set 100. In the illustrated embodiment of Figures 2 and 5, the cap 106c is provided with one or more protective ribs 106n disposed adjacent one or more vent holes or vent openings 106v. The one or more protective ribs 106n help to prevent the one or more vent holes 106v from being covered by the patient, a blanket, etc. while the patient is sleeping during PD therapy.

[0089] 2, 4 and 5, the lumen connector 104 and the body 106 of the filter housing 102 may be molded as a single structure, except for the cap 106c. The lumen connector 104 and the body 106 form a fresh PD fluid passageway 116 and a spent PD fluid passageway 118. As shown in FIG. 2, the fresh PD fluid passageway 116 extends through a fresh PD fluid port 104f in the lumen connector 104 toward a deflecting wall 106w located in the body 106 of the filter housing 102. The deflecting wall 106w redirects the fresh PD fluid along and over the deflecting wall 106w into an outer section 106o that resides over the outside of the flat sheet filter membrane 120. The outer section 106o is sized to distribute the fresh PD fluid across the upstream side of the filter membrane 120 for uniform distribution through the porous membrane. The fresh PD fluid is pressurized in the outer section 106o. The pressurization forces the fresh PD fluid through the flat sheet filter membrane 120 and into the filtered fluid compartment 106f of the body 106, which is primarily bounded by the underside of the flat sheet filter membrane 120 and the ribbed wall 106i, which has a series of ribs 106r that support the flat sheet filter membrane 120, particularly during negative patient drain pressures.

[0090] 2 further illustrates that in one embodiment, fresh and further filtered PD fluid flows from the filtered fluid compartment 106f of the body 106 through an outlet 106t provided in the ribbed wall 106i to a transferset side port 106p, through the transferset side port 106p, through a short tube 108 of the filter set 100, through the patient's transferset 58, and into the peritoneal cavity of the patient P. The transferset side port 106p extends from a used PD fluid tube 106u, which is described in more detail below. The short tube 108 (FIG. 1) extends over (or alternatively into) the transferset side port 106p, which is ultrasonically sealed, heat sealed, or solvent bonded to the transferset side port 106p.

[0091] 4 shows the ribbed wall 106i and side wall 106s of the body 106 in more detail. The ribbed wall 106i and side wall 106s define the filtered fluid compartment 106f. The ribbed wall 106i and side wall 106s are integrally molded with the fresh and spent PD fluid ports 104f, 104u, the transferset side port 106p, a series of ribs 106r, and the spent PD fluid tube 106u of the lumen side connector 104 in the illustrated embodiment. The side wall 106s in the illustrated embodiment includes or defines a continuous centering sealing rib 106x, which receives a mating groove 106g (FIG. 2) formed along the lower periphery of the cap 106c. The fit of sealing ribs 106x into grooves 106g ensures that cap 106c is properly positioned for ultrasonic sealing, heat sealing or solvent bonding to sidewall 106s.

[0092] 4 shows that the inner wall 106y extends inwardly from the side wall 106s to where the ribbed wall 106i drops down from the inner wall 106y to form the filtered fluid compartment 106f. The inner wall 106y is similarly provided with a continuous (or daisy chain) ring of material 106z, which ring indicates the location of the installed flat-sheet filter membrane 120. The ring of material 106z can help center the installed flat-sheet filter membrane 120 and / or can provide additional material to aid in ultrasonically sealing, heat sealing, or solvent bonding the filter membrane 120 to the inner wall 106y.

[0093] The series of ribs 106r formed by the ribbed wall 106i supports the flat sheet filter membrane 120 and allows it to be sized for ultimate filtration of fresh PD fluid over multiple patient fills of PD therapy. The series of ribs 106r supports the flat sheet filter membrane 120, particularly under negative fluid pressure applied through the spent PD fluid port 104u of the lumen-side connector 104. The series of ribs 106r also allows for the flow of filtered fresh PD fluid from the filtered fluid compartment 106f to the outlet 106t.

[0094] 2 and 4 in combination show how fresh PD fluid traveling through fresh PD fluid port 104f contacts deflecting wall 106w and flows upward into outer compartment 106o located below cap 106c. Fresh PD fluid distributes over flat sheet filter membrane 120 and is then pressurized through the porous walls of the filter membrane into filtrate compartment 106f, flowing along and around a series of ribs 106r until it exits through outlet 106t. The exiting fresh PD fluid flows to the patient through transfer set side port 106p.

[0095] 5 shows that the transferset side port 106p extends to a spent PD fluid tube 106u, which in one embodiment resides adjacent to the filtered fluid compartment 106f. The spent PD fluid tube 106u may be molded with a main portion of the body 106. The spent PD fluid tube 106u in the illustrated embodiment extends from the transferset side port 106p to a spent PD fluid port 104u of the lumen side connector 104, collectively forming a spent PD fluid passageway 118. The spent PD fluid port 104u is in sealed fluid communication with the spent PD fluid lumen 54 of the dual lumen patient line 50 during operation, as previously described.

[0096] The spent PD fluid tube 106u allows the spent PD fluid to be drawn through the body 106 of the filter housing 102 without contacting and potentially clogging the filter membrane 120. The spent PD fluid tube 106u provides an unobstructed, straight path for the spent PD fluid, the straight path having an inner diameter of 2 to 8 millimeters ("mm"), for example 4 mm, to help mitigate pressure loss through the filter set 100.

[0097] Although it is fluidly possible for the spent PD fluid to flow through the outlet 106t provided in the ribbed wall 106i and into the filtered fluid compartment 106f of the body 106, there is little incentive for the spent PD fluid to flow into the filtered fluid compartment 106f because negative pressure is applied only from within the spent PD fluid tube 106u. The control unit 40 of the PD machine 20 is also configured to close the fresh PD fluid valve 26a during patient drain, encouraging the spent PD fluid to flow along the spent PD fluid tube 106u rather than into the filtered fluid compartment 106f. Similarly, it is fluidly possible for the fresh PD fluid to flow back in the reverse direction up the spent PD fluid tube 106u during patient fill, although the required change in direction makes such a path much more tortuous than simply flowing to the patient P through the transfer set side port 106p. Additionally, the spent PD fluid tubing 106u and the spent PD fluid lumen 54 of the dual lumen patient tubing 50 will likely fill with fresh and / or used PD fluid during patient fill, and the spent PD fluid lumen 54 will be closed via the spent PD fluid valve 26b in the PD machine or cycler 20, thus leaving little or no room for fresh PD fluid to enter the spent PD fluid tubing 106u.

[0098] 6 and 7, different views of the outlet 106t from the filtered fluid compartment 106f to the transfer set side port 106p are shown. Here, it is conceivable that the outlet 106t provided in the ribbed wall 106i is covered with at least one hinged closure flap 106l, if necessary. In FIG. 6, two closure flaps 106l provided at the top of the spent PD fluid tube 106u and the outlet 106t hinge along a longitudinal hinge. In FIG. 7, one or more closure flaps 106l provided at the top of the spent PD fluid tube 106u and the outlet 106t hinge along at least one circumferential hinge. The hinge(s) may be a living hinge(s), and at least one flap 106l is molded with the ribbed wall 106i along one or more sides of the outlet 106t. During patient fill, the at least one closure flap 106l opens under positive pressure applied by freshly filtered PD fluid, allowing the fresh PD fluid to flow from the outlet 106t to the transfer set side port 106p. During patient drain, the flow of spent PD fluid across the at least one closure flap 106l closes the flap, thereby preventing the spent PD fluid from flowing through the outlet 106t. It is conceivable to form the at least one hinged closure flap 106l such that the flap is biased closed when not under positive pressure from the fresh PD fluid. Thus, the at least one hinged closure flap 106l provides the functionality of a one-way or check valve without the need for a separate valve.

[0099] With regard to priming the filter set 100 for treatment, the fresh PD fluid lumen 52 of the patient line 50 and the filter set 100 may or may not be primed with fresh PD fluid before the short tubing 108 is connected to the patient's transfer set 58. If primed, the user interface 48 may audibly, visually or audibly prompt the patient P to clip the patient line connector 56 and / or the filter set 100 to a clip provided by the housing 22 of the PD machine or cycler 20. The short tubing 108 may initially be attached to a cap (not shown) so that when the patient line connector 56 or the filter set 100 is clipped to the housing 22, the short tubing 108 hangs down from the filter set 100 and is closed to the environment via the cap. The control unit 40 then causes the PD fluid pump 24 to prime the fresh PD fluid lumen 52 with fresh PD fluid up to the filter membrane 120 with the fresh PD fluid valve 26a open and the spent PD fluid valve 26b closed. Here, air is forced out through the vent openings 106v.

[0100] When the fresh PD fluid lumen 52 is fully primed, the pressure sensors 28a and 28b detect a pressure rise because the fresh PD fluid has nowhere to go with the spent PD fluid valve 26b closed. Then, upon seeing a pressure rise with the filter membrane 120 fully wetted, the control unit 40 causes the spent PD fluid valve 26b to open, allowing the PD fluid pump 24 to push fresh PD fluid through the hydrophilic filter membrane 120 and into the filtered fluid compartment 106f, which pushes air through the interior compartment, into and through the spent PD fluid passageway 118 of the spent PD fluid tube 106u, into a portion of the spent PD fluid lumen 54. Thus, air is forced up the spent PD fluid lumen 54 toward the system drain. Control unit 40 can now be programmed to know and actuate several known volumetric strokes of PD fluid pump 24 necessary to properly prime the desired portions of filtered fluid compartment 106f, spent PD fluid passageway 118 of spent PD fluid tubing 106u, and spent PD fluid lumen 54. At this point, body 106 of filter set 100 is fully primed. It should be appreciated that filter set 100 does not need to be clamped to housing 22 for the above-described priming of body 106 of filter set 100 to be performed, however, doing so may help prevent dual lumen patient line 50 from kinking during such priming.

[0101] The user interface 48 of the PD machine or cycler 20 then audibly, visually or audiovisually prompts the patient P to remove the filter set 100 from the clip on the housing 22, remove the cap from the short tube 108, connect the short tube 108 to the patient's transfer set 58, and open the clamp on the patient's transfer set 58. Next, in one embodiment, the control unit 40, with the spent PD fluid valve 26b open and the fresh PD fluid valve 26a open or closed (likely closed), causes the PD fluid pump 24 to draw spent PD fluid from the patient to prime the short tube 108, which draws air from the short tube, through the spent PD fluid passageway 118 of the spent PD fluid tube 106u, into the spent PD fluid lumen 54 of the dual lumen patient line 50, and toward the drain of the PD machine or cycler 20. Such drawing of spent PD fluid may be part of the patient's initial drain. Thus, the amount of spent PD fluid removed from the patient, in one embodiment, is counted by control unit 40 (eg, by accumulating known volumetric strokes of PD fluid pump 24) as part of the initial drain amount of the treatment.

[0102] Alternatively, if a patient fill is the first operation to be performed after priming the fresh PD fluid lumen 52 and the body 106 of the filter set 100, the control unit 40 may or may not draw effluent from the patient to fully prime the short tube 108 before beginning the initial patient fill. That is, it is contemplated that the control unit 40 may allow a small amount of air present in the short tube 108 to be pushed back into the patient. However, if the control unit 40 draws an initial amount of effluent from the patient to prime the short tube 108, the control unit 40 may count any amount of effluent drawn from the patient as part of the subsequent initial drain (e.g., by accumulating known volumetric strokes of the PD fluid pump 24).

[0103] In an alternative embodiment, the filter set 100 is not clipped on the housing 22 and the short tubing 108 is first connected to the patient transfer set 58. The user interface 48 now audibly, visually or audiovisually advises the patient P to keep the patient transfer set 58 clamp closed until instructed to open the clamp. The procedure described above is then performed, with the patient transfer set clamp now performing the function of the cap on the end of the short tubing 108 in the above example. With the patient transfer set clamp closed, the control unit 40 causes fresh PD fluid to be primed through the fresh PD fluid lumen 52, the filter set body 106, and a portion of the spent PD fluid lumen 54 using the PD fluid pump 24 while sequencing the valves 26a and 26b as previously described.

[0104] In one embodiment, user interface 48 then prompts patient P to open the clamps on patient transfer set 58 and press a confirm button on user interface 48. When the confirm button is then pressed, control unit 40 sequences valves 26a and 26b and operates pump 24 as described above to draw spent PD fluid from the patient P's peritoneal cavity and prime the short tubing 108 and the spent PD fluid passageway 118 of spent PD fluid tubing 106u with patient effluent. The effluent priming of short tubing 108 may again be part of the initial patient drain.

[0105] Drawing spent PD fluid from the patient to prime the short tube 108 assumes that there is spent PD fluid to be removed from the patient at the beginning of the treatment. This is true in many cases where the patient is full of spent PD fluid at the beginning of the treatment, either from the last fill of a previous treatment or from a midday exchange. However, in some cases, the patient is dry at the beginning of the treatment. It is conceivable that the control unit 40 of the PD machine or cycler 20, which may be dedicated to a single patient at a given time, knows the treatment schedule of the patient, and therefore, the control unit 40 knows when to start the next treatment when the patient is in a dry state with no or very little PD fluid used. Now, it is conceivable that the control unit 40, instead of attempting to completely drain the patient with the final drain of the previous treatment, allows some residual amount of effluent to remain in the patient's peritoneal cavity after the treatment. The residual amount may be, for example, 50 milliliters ("ml") or more, as necessary, to allow the patient's indwelling PD catheter to access the residual effluent. The residual volume must be at least sufficient to prime any air through the proximal end of the short tube 108 at the junction of the filter set 100 .

[0106] The above priming procedure is advantageous for several reasons. First, the step of having the patient clip the patient line connector 56 to a clip provided by the housing 22 of the PD machine or cycler 20 may be omitted. The need for the patient line connector 56 to be fitted with a vent cap and / or the housing 22 of the PD machine or cycler 20 to have a sensor to detect when fresh PD fluid reaches the patient line connector 56 may also be eliminated. Both savings reduce cost and complexity. Second, after treatment, the patient disconnects the transfer set connector 110 from the patient's transfer set 58 and then seals the transfer set 58 with a cap (not shown) having a disinfectant such as iodine to help prevent peritonitis due to, for example, patient contact contamination. The cap is then removed and replaced with a new transfer set connector 110 of a new filter set 100 at the start of the next treatment. However, residual disinfectant, such as residual iodine, remains. The priming method disclosed herein carries residual disinfectant away under negative pressure into the spent PD fluid lumen 54 of the dual lumen patient line 50 instead of sending it to the patient. Doing so may prevent health issues, especially for sensitive patients.

[0107] It should be understood that various modifications and changes to the presently preferred embodiment described herein will be apparent to those skilled in the art.It is therefore intended that any or all of such modifications and changes may be covered by the appended claims.For example, the dual lumen patient line 50 may alternatively be a single lumen patient line, and the filter set 100 may include check valves provided in the fresh and spent PD fluid ports 104f, 104u of the lumen side connector 104, for example, to direct the fresh and spent PD fluid to desired locations within the set.

Claims

1. A peritoneal dialysis ("PD") system (10), comprising: A PD machine (20); a patient line (50) extending from the PD machine (20); a filter set (100) in fluid communication with the patient line (50); Equipped with The filter set (100) includes a filter membrane (120) positioned and arranged so that fresh PD fluid flows through the filter membrane (120) into a filtered fluid compartment (106f), the filtered fluid compartment (106f) includes an outlet (106t) to a spent PD fluid tube (106u), the spent PD fluid tube (106u) is in fluid communication with a port (106p), and the spent PD fluid tube (106u) is positioned and arranged to transport spent PD fluid past the filter membrane (120) without contacting the filter membrane (120).

2. 2. The PD system of claim 1, wherein the patient line is a dual lumen patient line including a fresh PD fluid lumen and a spent PD fluid lumen, the spent PD fluid lumen being disposed in fluid communication with the spent PD fluid tubing.

3. 3. The PD system of claim 2, wherein the filter set includes a fresh PD fluid port for fluid communication with the fresh PD fluid lumen and a spent PD fluid port for fluid communication with the spent PD fluid lumen.

4. The PD system (10) of claim 3, wherein the spent PD fluid tube (106u) is in fluid communication with the spent PD fluid port (104u).

5. The PD system (10) of any one of claims 1 to 4, wherein the port (106p) extends to a spent PD fluid tube (106u).

6. The PD system (10) of any one of claims 1 to 4, wherein the outlet (106t) is releasably covered by at least one hinged closure flap (106l).

7. The PD system (10) of any one of claims 1 to 4, comprising at least one rib (106r) located within the filtered fluid compartment (106f) for supporting the filter membrane (120).

8. The PD system (10) of any one of claims 1 to 4, wherein the filter membrane (120) is a flat-sheet filter membrane, and the filter set (100) includes an outer compartment (106o) located on the opposite side of the flat-sheet filter membrane from the filtered fluid compartment (106f).

9. The PD system (10) of claim 8, wherein the filter set (100) includes a fresh PD fluid port (104f) positioned and arranged to introduce fresh PD fluid into the outer compartment (106o).

10. 10. The PD system of claim 9, wherein the filter set includes a deflection wall positioned and arranged to deflect fresh PD fluid from the fresh PD fluid port toward the outer compartment.

11. 9. The PD system of claim 8, wherein the filter set includes a cap that cooperates with the filter membrane to form the outer compartment, the cap including at least one vent opening and at least one hydrophobic membrane that seals and covers the at least one vent opening.

12. The PD system (10) of any one of claims 1 to 4, wherein the filter set (100) is configured to connect directly to a patient's transfer set, or the filter set (100) includes flexible tubing (108) configured to connect to the patient's transfer set.

13. 5. The PD system of claim 1, wherein the PD machine is configured to close a spent PD fluid valve during patient fill and force filtered fresh PD fluid to flow to the port rather than along the spent PD fluid tubing.

14. 5. The PD system of claim 1, wherein the PD machine is configured to close a fresh PD fluid valve during patient drainage, forcing spent PD fluid to flow along the spent PD fluid tubing rather than into the filtered fluid compartment.

15. A filter set (100), comprising: Port (106p) and A filter membrane (120) and Equipped with The filter membrane (120) is positioned and arranged so that fresh PD fluid flows through the filter membrane (120) into a filtered fluid compartment (106f), the filtered fluid compartment (106f) includes an outlet (106t) to a spent PD fluid tube (106u), the spent PD fluid tube (106u) is in fluid communication with the port (106p), and the spent PD fluid tube (106u) is positioned and arranged to transport spent PD fluid past the filter membrane (120) without contacting the filter membrane (120).

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