Peritoneal dialysis system with patient line filter

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 at least one filter membrane (120a, 120b, e.g., a bacterial reduction or sterilizing grade filter membrane) positioned and arranged such that fresh PD fluid flows through the at least one filter membrane (120a, 120b) before exiting the filter set (100), and the filter set (100) further includes a spent PD fluid tubing (106u) positioned and arranged to transport spent PD fluid past the at least one filter membrane (120a, 120b) without contacting the at least one filter membrane (120a, 120b). Methods for 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 / 291,058, 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 treatment, and more particularly to filtration of treatment fluids during dialysis fluid treatment. [Background technology]

[0003] background A variety of causes can cause a person's renal system to fail. Renal failure results in several physiological disturbances: it is no longer possible to balance water and minerals or 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 by dialysis. Dialysis removes waste, toxins and excess water from the body that normally functioning kidneys would otherwise remove. Dialysis treatment for replacement of kidney function is important for many people because the treatment is life-saving.

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

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

[0007] Hemodiafiltration ("HDF") is a procedure 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 delivered directly to the extracorporeal circuit to provide convective clearance.

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

[0009] Another type of renal failure treatment is peritoneal dialysis ("PD"), in which dialysis solution, also called dialysis fluid or PD fluid, is infused into a patient's peritoneal cavity via a catheter. The PD fluid contacts the peritoneal membrane within the patient's peritoneal cavity. 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 pressure 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 therapy, including continuous ambulatory peritoneal dialysis ("CAPD"), automated peritoneal dialysis ("APD"), tidal flow dialysis, and continuous flow peritoneal dialysis ("CFPD"). CAPD is a manual dialysis procedure, in which the patient manually connects an implanted catheter to a drain to allow spent PD fluid to drain from the patient's peritoneal cavity. The patient then switches the fluid communication, connecting the patient catheter to a bag of fresh PD fluid and infusing the patient with fresh PD fluid through the catheter. The patient disconnects the catheter from the fresh PD fluid bag, allowing the PD fluid to remain in the patient's peritoneal cavity, where waste, toxins, and excess water are transported. 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 do not require the patient to manually perform the treatment cycles and do not require the patient to have supplemental substances delivered 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 cavity. APD machines also allow the PD fluid to dwell within the cavity, allowing waste, toxins and excess water to be transported. The source may contain multiple liters of dialysis fluid, including several solution bags.

[0012] The APD machine pumps spent PD fluid out of the patient's peritoneal cavity through a catheter to drain it. 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 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 fluids must 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 the procedure, 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 delivered to the patient. Summary of the Invention [Means for solving the problem]

[0015] overview 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 with a disposable patient line. In either configuration, the distal end of the filter set can be connected to a patient transfer set that is in fluid communication with the patient's indwelling catheter.

[0016] The PD machine or cycler can 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 can be flow-through and durable as well 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. While a single PD fluid pump can be used, it should be understood that dedicated fresh and spent PD fluid pumps can alternatively be used. Also, a single PD fluid pump can include multiple pumping chambers for a more continuous PD fluid flow.

[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 and can be sealed (e.g., ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via ultraviolet ("UV") curable adhesive) 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, solvent bonded, laser welded or sealed via UV curable adhesive) to a transferset connector that connects directly to a mating connector of the patient's transferset or to a mating connector of a short tube disposed between the body and the patient's transferset. Alternatively, the transferset connector may be disposed at the end of a short tube extending from the body. Here, the body includes a transferset port (e.g., molded with a transferset port) and a short tube extends into or over the transferset port for welding to the port. The body, lumen connector, and transferset connector or port are sometimes 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 located in the body of the filter housing. The wall splits the fresh PD fluid outward in two directions, forming a first outer compartment fresh PD fluid passageway and a second outer compartment fresh PD fluid passageway. The first outer compartment fresh PD fluid passageway extends along and then through the wall in a first direction, turning at a right angle to a first outer compartment that is outside the first flat sheet filter membrane, etc. The second outer compartment fresh PD fluid passageway extends along and then through the wall in a second direction, turning at a right angle to a second outer compartment that is also outside the second flat sheet filter membrane, etc. Fresh PD fluid is pressurized in the first and second outer compartments. The pressurization forces fresh PD fluid through the filter membrane and into an interior compartment of the body that is bounded in part by the inner surfaces of the first and second flat sheet filter membranes.

[0020] The filter membrane may be a bacterial reducing or sterilizing grade hydrophilic membrane and may be formed with porous walls having a pore size of about 0.2 microns through which fresh PD fluid flows for further filtration. By providing multiple flat sheet membranes, the membranes, and therefore the filter housing of the filter set, can be made shorter while still providing the necessary filtration surface area required for the multiple patient loadings of a PD procedure. Since the patient generally sleeps close to the filter set during the procedure, a shorter filter housing is better for patient comfort.

[0021] Fresh and further filtered PD fluid, in one embodiment, flows from the inner compartment of the body through the transfer set side port, through the short tube of the filter set, through the patient's transfer set, and into the patient's peritoneal cavity. The transfer set side port in one embodiment includes an internal stopper that sets the insertion position of the short tube, e.g., flexible tubing, or at least provides a position where the short tube can no longer be inserted into the transfer set side port. The internal stopper, in one embodiment, is offset a desired distance from the end of the internal spent PD fluid tube. The spent PD fluid tube may be molded with the primary portion of the body. The spent PD fluid tube extends through the inner compartment of the body to a spent PD fluid port provided by the lumen side connector. 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 allows the spent PD fluid to be drawn through the body of the filter housing without contacting and potentially clogging any of the filter membranes. The spent PD fluid tube also provides a well-defined straight path for the spent PD fluid, which helps mitigate pressure loss through the filter set. Although it is fluidically possible for the spent PD fluid to flow along the outside of the spent PD fluid tube into the inner compartment within the body, there is little incentive for the spent PD fluid to flow along the outside of the spent PD fluid tube because negative pressure is only applied from the inside of the spent PD fluid tube. Similarly, it is fluidically possible to invert the spent PD fluid tube to allow fresh PD fluid to flow, but the change in direction required makes such a path much more tortuous than simply flowing through a transfer set side port to the patient. Additionally, the spent PD fluid tubing and the spent PD fluid lumen of the dual lumen patient tubing will likely fill with PD fluid during patient fill, and because the spent PD fluid lumen is closed in the PD machine or cycler, there is little or no room for fresh PD fluid to enter the spent PD fluid tubing.

[0023] The inner compartment of the body, in one embodiment, is provided with a series of ribs that support the first and second flat sheet filter membranes when placed under negative fluid pressure. In this manner, the filter membranes and the inner compartment can be sized as needed to provide the desired filtration capacity. In one embodiment, the series of ribs and their support structures are co-molded with the used PD fluid tube and the sidewall of the body. The first and second flat sheet filter membranes are sealed in place to the inner portion of the sidewall of the body via ultrasonic sealing, heat sealing, solvent bonding, laser welding, or sealing with a UV-cured adhesive.

[0024] The filter housing body includes first and second lids that may be formed from the same material as the remainder of the filter housing body. The first and second lids may be ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via UV curable adhesive to the outer portion of the sidewall of the body. A tongue and groove fit may be provided between the first and second lids and the sidewall to center the lids for sealing and / or to act as a flash trap for material melted by the welding or other process used to seal the lids to the body. The first and second lids each form the outside of a first and second outer compartment into which fresh PD fluid flows before passing through the filter membrane.

[0025] The first and second lids may be formed with one or more vents, each vent being covered on the inside of the lid with a hydrophobic membrane, which may be ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via a UV curable adhesive to the inside surface of the lid and around the at least one vent opening. The one or more hydrophobic membranes allow air to be vented to the atmosphere when fresh PD fluid is pressurized within 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.

[0026] A gasket, such as a silicone or polyvinyl chloride ("PVC") rubber gasket, is fitted over and / or into the fresh and used PD fluid ports of the lumen-side connector of the filter housing. In one embodiment, the gasket provides a dual seal against a mating patient line connector. The patient line connector includes fresh and used ports that extend into the fresh and used PD fluid ports of the lumen-side connector. The gasket includes a port seal between the mating fresh and used PD fluid ports of the patient line connector and the lumen-side connector. The port seal and the fresh and used ports of the patient line connector may be tapered to narrow as they extend into the filter housing. The port seal is the first seal. The patient line connector includes a flange having a raised continuous rib extending around the flange. The flange and rib translate toward the flange portion of the gasket when the patient line connector is connected to the lumen-side connector. When the patient line connector is fully connected to the lumen side connector, the raised rib extends into the deformable flange portion of the gasket and the gasket is compressed around the raised rib to form a second seal.

[0027] 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 under positive pressure to drain. 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. That same pressure sensor can be used during patient fill to measure the positive pump pressure (which is 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), which is desirable because the measured pressure is 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 and more accurately reflects the pressure at which the PD fluid is delivered to the patient.

[0028] Also described herein are multiple methods for priming the filter set of the present disclosure. In a first embodiment, the filter set may be clipped on the cycler housing and the short tube is not initially connected to the patient's transfer set. Here, a cap on the end of the short tube acts to force the fresh PD fluid used for priming, and therefore the air, back up the spent PD fluid side of the filter set towards the drain. In a second embodiment, the filter set is not clipped on the cycler housing and the short tube is initially connected to the patient's transfer set. Here, a twist clamp on the patient's transfer set acts to force the fresh PD fluid used for priming, and therefore the air, back up the spent PD fluid side of the filter set. The control unit then primes the fresh PD fluid through the fresh PD fluid lumen, the body of the filter set, and a portion of the spent PD fluid lumen via the PD fluid pump. The fresh and spent PD fluid valves are sequenced to do so. Then, with everything but the short tube primed, in the first embodiment, the patient is prompted to connect the short tube to the patient's transfer set and open the transfer set clamp. In the second embodiment (short tubing already connected), the patient is prompted to open the transfer set clamp. In either case, the control unit may cause the PD fluid pump to apply negative pressure through the spent PD fluid lumen, e.g., as part of the initial drain, to draw spent PD fluid from the patient and prime the short tubing.

[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 at least one filter membrane, the at least one filter membrane positioned and arranged such that fresh PD fluid flows through the at least one filter membrane before exiting the filter set, and the filter set further includes a used PD fluid tube positioned and arranged to transport used PD fluid through the at least one filter membrane without contacting the at least one filter membrane.

[0030] In a second aspect of the present disclosure, which can 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, and the spent PD fluid lumen is disposed in fluid communication with the spent PD fluid tube.

[0031] In a third aspect of the present disclosure, which can 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 can 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 can be combined with any other aspect or portion thereof, the filter set includes a compressible gasket configured to seal fresh and used PD fluid ports to a patient line connector located at the end of a dual lumen patient line.

[0034] In a sixth aspect of the present disclosure that can be combined with any other aspect or portion thereof, a filter set includes first and second filter membranes separated by an inner compartment through which fresh PD fluid is filtered by the first and second filter membranes, and a used PD fluid tube extends through the inner compartment.

[0035] In a seventh aspect of the present disclosure that can be combined with any other aspect or portion thereof, the PD system includes at least one rib located within the inner compartment for supporting the first and second filter membranes.

[0036] In an eighth aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the filter set includes a transfer set side port through which fresh PD fluid and spent PD fluid flow, and the spent PD fluid tube extends into the transfer set side port.

[0037] In a ninth aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the transfer set side port defines an internal stopper against which the tube can be abutted, the internal stopper extending into the transfer set side port away from the end of the used PD fluid tube.

[0038] In a tenth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the filter set includes at least one outer compartment that is dimensioned to move fresh PD fluid across the upstream side of the at least one filter membrane.

[0039] In an eleventh aspect of the present disclosure that can be combined with any other aspect or portion thereof, the at least one filter membrane is a flat sheet filter membrane.

[0040] In a twelfth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the filter set includes a deflection wall positioned and arranged to move incoming fresh PD fluid toward at least one outer compartment.

[0041] In a thirteenth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the filter set includes at least one lid cooperating with at least one filter membrane to form at least one outer compartment.

[0042] In a fourteenth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the at least one lid includes at least one vent opening and at least one hydrophobic membrane sealingly covering the at least one vent opening.

[0043] In a fifteenth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the filter set includes at least one sidewall, at least one lid is sealed to an outer portion of the at least one sidewall, and at least one filter membrane is sealed to an inner portion of the at least one sidewall.

[0044] In a sixteenth aspect of the present disclosure, which 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.

[0045] In a seventeenth aspect of the present disclosure, which can 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 at least one filter membrane during patient fill.

[0046] In an eighteenth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the at least one filter membrane is a bacteria-reducing filter membrane or a sterilizing grade filter membrane.

[0047] In a nineteenth aspect of the present disclosure that can 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 first and second filter membranes separated by an inner compartment through which fresh PD fluid is filtered by the first and second filter membranes, and the filter set is further configured to allow used PD fluid to flow through the inner compartment.

[0048] In a twentieth aspect of the present disclosure that can be combined with any other aspect or portion thereof, the PD system includes at least one rib located within the inner compartment to support the first and second filter membranes, and the spent PD fluid flows around the at least one rib before exiting the inner compartment.

[0049] In a twenty-first aspect of the present disclosure that can be combined with any other aspect or portion thereof, a filter set includes a body, at least one filter membrane positioned and arranged within the body such that fresh peritoneal dialysis ("PD") fluid flows through the at least one filter membrane before exiting the filter set, and a used PD fluid tube positioned and arranged within the body to transport used PD fluid through the at least one filter membrane without contacting the at least one filter membrane.

[0050] In a twenty-second aspect of the present disclosure that can be combined with any other aspect or portion thereof, a filter set includes a body, at least one filter membrane positioned and arranged within the body such that fresh peritoneal dialysis ("PD") fluid flows through the at least one filter membrane before exiting the filter set, and at least one lid including at least one vent opening and at least one protective rib positioned adjacent to the at least one vent opening to keep the at least one vent opening uncovered during operation.

[0051] In a twenty-third aspect of the present disclosure, which can be combined with any other aspect or portion thereof, there is provided a method for priming a filter set connected to a dual lumen patient line, wherein during treatment, a tube is located between the filter set and a patient's transfer set, the method including: (i) delivering fresh peritoneal dialysis ("PD") fluid to the filter set through a fresh PD fluid lumen of the dual lumen patient line; and (ii) forcing the fresh PD fluid through at least one filter membrane of the filter set such that the fresh PD fluid displaces air toward 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 tube, through the spent PD fluid portion of the filter set, and into the spent PD fluid lumen of the dual lumen patient line.

[0052] In a twenty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, drawing in spent PD fluid is provided as part of the initial patient drain.

[0053] In a twenty-fifth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, between pushing fresh PD fluid through at least one filter membrane and drawing spent PD fluid from the patient, the patient is prompted to connect a tube to the patient's transfer set.

[0054] In a twenty-sixth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, between pushing fresh PD fluid through at least one filter membrane and drawing used PD fluid from the patient, the patient is prompted to open a clamp on the patient's transfer set.

[0055] In a twenty-seventh aspect of the present disclosure, which can be combined with any other aspect or portion thereof, air is primed through at least one vent opening of the filter set while delivering fresh PD fluid through the fresh PD fluid lumen of the dual lumen patient line.

[0056] In a twenty-eighth aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the fresh PD fluid valve is opened and the used PD fluid valve is closed while delivering fresh PD fluid through the fresh PD fluid lumen of the dual lumen patient line.

[0057] In a twenty-ninth aspect of the present disclosure that can be combined with any other aspect or portion thereof, a used PD fluid valve is open while fresh PD fluid is forced through at least one filter membrane of the filter set.

[0058] In a thirtieth aspect of the present disclosure that can be combined with any other aspect or portion thereof, a spent PD fluid valve is open during drawing of spent PD fluid from the patient.

[0059] In a thirty-first aspect of the present disclosure, which can 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 to force the fresh PD fluid through at least one filter membrane.

[0060] In a thirty-second aspect of the present disclosure, which can be combined with any other aspect or portion thereof, the method includes sensing a pressure increase from (i) delivering fresh PD fluid to a filter set through a fresh PD fluid lumen of a dual lumen patient line to (ii) forcing the fresh PD fluid through at least one filter membrane.

[0061] In a thirty-third aspect of the present disclosure that can be combined with any other aspect or portion thereof, the used PD fluid portion of the filter set includes a used PD fluid tube.

[0062] In a thirty-fourth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the used PD fluid drawn from the patient is a residual effluent from a previous process left for the purpose of priming the tubing.

[0063] In a thirty-fifth embodiment of the present disclosure that can be combined with any other embodiment or portion thereof, the amount of the residual effluent is at least 50 ml.

[0064] In a thirty-sixth aspect of the present disclosure that may be combined with any other aspect or portion thereof, any of the features, functions, and alternatives described in association with any one or more of Figures 1-8B may be combined with any of the features, functions, and alternatives described in association with any other of Figures 1-8B.

[0065] 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.

[0066] 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 with limited or perhaps no contact with the filter membrane.

[0067] A further advantage of the present disclosure is that it provides a filter set that efficiently sizes and spaces the filter membrane to reduce size and aid in patient comfort.

[0068] 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.

[0069] 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 of the advantages listed herein, and it is expressly contemplated that each advantageous embodiment may be separately claimed. Furthermore, it should be noted that the language used in this specification has been selected primarily for ease of reading and explanation purposes, and is not intended to limit the scope of the inventive subject matter. [Brief description of the drawings]

[0070] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of a peritoneal dialysis system having a filter set of the present disclosure.

[0071] [Diagram 2] FIG. 2 is an exploded perspective view of one embodiment of a filter set of the present disclosure.

[0072] [Diagram 3] FIG. 3 is a cross-sectional perspective view highlighting the fresh PD fluid inlet path of one embodiment of the filter set of the present disclosure.

[0073] [Figure 4] FIG. 4 is a cross-sectional perspective view highlighting the spent PD fluid exit path of one embodiment of the filter set of the present disclosure.

[0074] [Diagram 5] FIG. 5 is a cross-sectional perspective view highlighting a used PD fluid tube and filter membrane support ribs of one embodiment of a filter set of the present disclosure.

[0075] [Figure 6] FIG. 6 is a cross-sectional elevational view highlighting the outer fresh PD fluid compartment and hydrophobic membrane of one embodiment of the filter set of the present disclosure.

[0076] [Figure 7] 7A and 7B are cross-sectional perspective views of a second embodiment of a filter set of the present disclosure.

[0077] [Figure 8] 8A and 8B are perspective views of one embodiment of a filter set body of the present disclosure having a ribbed vent opening cover. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0078] 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 may 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, the reusable patient line 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 merged into or formed with a 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.

[0079] The PD machine or cycler 20 can include a housing 22 with 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 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 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 be less accurate such that the machine or cycler 20 provides a volume control device such as one or more flow meters (not shown).

[0080] Alternatively, pump 24 may be a disposable type PD fluid pump that includes pump actuators that actuate 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. Additionally, a single PD fluid pump 24 may include multiple pumping chambers for a more continuous flow of PD fluid.

[0081] The PD machine or cycler 20 also includes a number of valves 26a, 26b, 26m, 26n, which may 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 valve seats on tube segments or cassette bases. 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.

[0082] The machine or cycler 20 likely includes 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 valve also includes 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 valve also includes 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 valve further includes a drain valve 26n that is controlled to allow the spent PD fluid to be delivered via a drain line 60 to a house drain or drain container.

[0083] The machine 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 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 the filter membrane discussed herein during patient fill. Pressure sensor 28b, perhaps more importantly, is positioned to sense the pressure of the fresh PD fluid downstream of the filter membrane discussed herein during patient fill.

[0084] The pump 24 and valves 26a-26n in the illustrated embodiment are under the automated control of a control unit 40 provided by the machine or cycler 20 of the system 10, and the pressure sensors 28a, 28b (and other sensors) output 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. The control unit 40 receives, stores, and processes signals or outputs from the pressure sensors 28a, 28b and other sensors provided by the machine or cycler 20, such as one or more temperature sensors 30 and one or more conductivity sensors (not shown). Using pressure feedback from one or more of pressure sensors 28a, 28b, control unit 40 can control 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).

[0085] 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, such as 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 procedure. 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.

[0086] 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 a membrane switch. 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, for transmitting treatment data to and receiving prescription orders from a physician or clinician server that interfaces with a physician or clinician's computer.

[0087] 1 and 2, the fresh and used PD fluid lumens 52 and 54 of the dual lumen patient line 50 may again be reusable or disposable. In an example 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 can be sealed (e.g., ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via an ultraviolet ("UV") curable adhesive) to or molded with the filter set body 106. The body 106 in the illustrated embodiment is connected to a short, e.g., flexible, tube 108 that extends to a transferset connector 110 that connects directly to a mating connector on 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 result in a combined rigid assembly that is uncomfortable for the patient P. The space provided by the tube 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 may be formed with the body or attached to the body 106.

[0088] If the dual lumen patient line 50 is disposable, the lumen side connector 104 may alternatively simply include ports, e.g., fresh and used PD fluid ports 104f and 104u, over which or into which the fresh and used PD fluid lumens 52 and 54, respectively, extend for ultrasonic sealing, heat sealing, solvent bonding, laser welding or sealing via UV curable adhesive to the ports. In the illustrated embodiment, the fresh port 104f and used port 104u are surrounded by a threaded shroud 104s, which may form a luer-type connection with a mating patient line connector 56. A compressible gasket 112 is provided to seal the ports 104f and 104u to the mating ports of the patient line connector 56, as described in detail herein. Caps 114a and 114b are provided on both ends of the filter set 100 (assuming the dual lumen patient line 50 is reusable) after the set has been sterilized, e.g., via irradiation, steam or ethylene oxide, to maintain sterility. To use filter set 100, the patient or user removes and discards caps 114a and 114b.

[0089] Lumen side connector 104 and body 106 are sometimes referred to herein as filter housing 102. Filter housing 102, transfer set side connector 110, caps 114a and 114b, and any other rigid or semi-rigid polymers associated with filter set 100 may be made of any one or more plastics, such as polystyrene ("PS"), polycarbonate ("PC"), blends of polycarbonate and acrylonitrile-butadiene-styrene ("PC / ABS"), polyvinyl chloride ("PVC"), polyethylene ("PE"), polypropylene ("PP"), polyethylene terephthalate ("PET"), or polyesters such as polyester elastomers, or polyurethane ("PU"). 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 from plasticized PVC or a non-PVC material such as polybutadiene ("PBD") or PP.

[0090] 2 also shows that the lids 106a, 106b are ultrasonically sealed, heat sealed, solvent bonded, or laser welded or sealed via UV curable adhesive to the sidewalls 106s of the body 106 to complete the body. Prior to sealing the lids 106a, 106b to the sidewalls 106s of the body 106, the first and second flat sheet filter membranes 120a, 120b are ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via UV curable adhesive to the inner portion of the sidewalls 106s of the body 106 around their periphery. The first and second flat sheet filter membranes 120a, 120b are made of an embodiment of a hydrophilic material that may have a pore size of about 0.2 microns through which the fresh PD fluid flows for further filtration. The filter membranes 120a, 120b can be made of, for example, polysulfone or polyethersulfone blended with polyvinylpyrrolidone. In one embodiment, the size and resulting surface area of ​​the filter membranes 120a, 120b may be based at least in part on one or more of the expected operating PD fluid pressure and flow rate provided by the PD machine or cycler 20.

[0091] 2 further illustrates that the lids 106a, 106b may be provided with vent openings 106o that allow air to escape from the fresh PD fluid before being filtered through the filter membranes 120a, 120b. To maintain sterility within the body 106, the hydrophobic membranes 122a, 122b, 122c, 122d, etc. are ultrasonically sealed, heat sealed, solvent bonded, laser welded or sealed via UV curable adhesive around the inner surface of their respective lids 106a, 106b and surrounding their respective vent openings 106o. The hydrophobic membranes 122a, 122b, 122c, 122d, etc. may be made from, for example, polytetrafluoroethylene ("PTFE"). Although multiple sets of vent openings 106o and corresponding hydrophobic membranes 122a, 122b, 122c, 122d are shown with each lid 106a, 106b, (i) only a single set of vent openings and corresponding hydrophobic membranes may be provided with each lid 106a, 106b, or (ii) one or more sets of vent openings and corresponding hydrophobic membranes may be provided with only a single lid 106a, 106b.

[0092] 3-6, there is shown in more detail the lumen connector 104 and body 106 of the filter housing 102 and gasket 112, which may be molded as a unitary structure except for the lids 106a, 106b. The lumen connector 104 and body 106 form a fresh PD fluid passageway 116 and a spent PD fluid passageway 118. As shown in FIG. 3, 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 splits the fresh PD fluid outward in two directions, forming a first outer compartment fresh PD fluid passageway 106c and a second outer compartment fresh PD fluid passageway 106d. The fresh PD fluid passageway 106c of the first outer compartment extends in a first direction along and past the deflecting wall 106w, making a right-angle turn or other such change of direction to the first outer compartment 106e (FIG. 6) that is outside the first flat sheet filter membrane 120a. The fresh PD fluid passageway 106d of the second outer compartment extends in a second direction along and past the deflecting wall 106w, making a right-angle turn or other such change of direction to the second outer compartment 106f (FIG. 6) that is outside the second flat sheet filter membrane 120b. The outer compartments 106e, 106f are sized to move fresh PD fluid across the upstream side of the filter membranes 120a, 120b for uniform distribution through the membranes. The fresh PD fluid is pressurized in the first and second outer compartments 106e, 106f. The pressurization forces fresh PD fluid through the filter membranes 120a, 120b and into the inner compartment 106i of the body 106, which is bounded in part by the inner surfaces of the first and second flat sheet filter membranes 120a, 120b.

[0093] The filter membranes 120a, 120b may be bacteria-reducing or sterilizing grade hydrophilic membranes and may be formed with porous walls having a pore size of about 0.2 microns through which fresh PD fluid flows for further filtration. By providing multiple flat sheet membranes 120a, 120b, the membranes, and therefore the filter housing 102 of the filter set, can be made shorter while still providing the necessary filtration surface area required across multiple patient loads of a PD procedure. Since the patient P (FIG. 1) generally sleeps close to the filter set 100 during the procedure, a shorter filter housing 102 is better for patient comfort. However, it should be understood that a single filter membrane 120a or 120b may alternatively be provided.

[0094] In one embodiment, fresh and further filtered PD fluid flows from the inner compartment 106i of the body 106 through the transfer set port 106p of the body, through the short, e.g., flexible, tube 108 of the filter set 100, through the transfer set 58, and into the peritoneal cavity of the patient P. As shown in FIGS. 3-5, the transfer set port 106p in one embodiment includes an internal stop 106t that sets the insertion position of the tube 108, or at least provides a position where the short tube 108 can no longer be inserted into the transfer set port 106p. The internal stop 106t is set from the beginning or end of an internal used PD fluid tube 106u, which in one embodiment may be molded with the main portion of the body 106. The used PD fluid tube 106u extends through the inner compartment 106i of the body 106 and partially into a used PD fluid port 104u provided by the lumen connector 104. 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.

[0095] 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 any of the filter membranes 120a, 120b and potentially clogging the filter membranes 120a, 120b. The spent PD fluid tube 106u also provides a well-defined straight path for the spent PD fluid (e.g., having an inner diameter of 2 millimeters ("mm") to 8 mm, e.g., about 3 mm or 4 mm), helping to mitigate pressure loss through the filter set 100. Although it is fluidly possible for the spent PD fluid to flow along the outside of the spent PD fluid tube 106u into the inner compartment 106i of the body 106, because negative pressure is applied only from within the spent PD fluid tube 106u, there is little incentive for the spent PD fluid to flow along the outside of the spent PD fluid tube. Similarly, while it is fluidly possible for fresh PD fluid to flow back through the spent PD fluid tubing 106u, the required change in direction would make such a path much more tortuous than simply flowing through the transfer set side port 106p to the patient P. Also, because the spent PD fluid tubing 106u and the spent PD fluid lumen 54 of the dual lumen patient tubing 50 are likely filled with PD fluid during patient fill, and the spent PD fluid lumen is closed by the PD machine or cycler 20, there is little or no room for fresh PD fluid to enter the spent PD fluid tubing.

[0096] The inner compartment 106i of the body 106, in one embodiment, is provided with a series of ribs 106r that support the first and second flat sheet filter membranes 120a, 120b (FIG. 6) when placed under negative fluid pressure. In this manner, the filter membranes 120a, 120b and the inner compartment 106i can be sized as needed to provide the desired filtration capacity. In one embodiment, the series of ribs 106r and their support structures 106v are co-molded with the spent PD fluid tube 106u and the sidewall 106s of the body 106. FIG. 6 shows that the first and second flat sheet filter membranes 120a, 20b are sealed in place to the inner portion of the sidewall 106s of the body 106 via ultrasonic sealing, heat sealing, solvent bonding, laser welding, or sealing with a UV-curable adhesive.

[0097] 2 and 6 show that the body 106 of the filter housing 102 includes first and second lids 106a, 106b that may be formed from the same material as the remainder of the body. The first and second lids 106a, 106b may be ultrasonically sealed, heat sealed, solvent bonded, laser welded, or sealed via a UV curable adhesive to the outer portion of the sidewall 106s of the body 106. For example, a tongue and groove fit via a tongue 106m formed in the lids 106a, 106b and a groove 106g formed in the sidewall 106s may be provided between the first and second lids 106a, 106b and the sidewall 106s to center the lids for sealing and / or act as a flash trap for material melted by a welding or other process used to seal the lids to the body. The first and second lids 106a, 106b respectively form the exterior of first and second outer compartments 106e, 106f into which fresh PD fluid enters before passing through filter membranes 120a, 120b.

[0098] The first and second lids 106a, 106b may be formed with one or more vents 106o (FIGS. 2, 8A, 8B). FIG. 2 and FIG. 6 show that each vent 106o is covered with a hydrophobic membrane 122a, 122b, 122c, 122d on the inside of the respective lid 106a, 106b, which may be ultrasonically sealed, heat sealed, solvent bonded, laser welded, or sealed via UV curable adhesive to the inside of the respective lid. The one or more hydrophobic membranes 122a, 122b, 122c, 122d allow air to be vented to the atmosphere during priming and at any time during treatment when fresh PD fluid is pressurized in the outer compartments 106e, 106f of the body 106 before being filtered through the hydrophilic sheet membranes 120a, 120b, which may improve the performance of the membrane in addition to removing air from the filter set 100.

[0099] With regard to priming the filter set 100 for a procedure, the patient line 50 and fresh PD fluid lumen 52 of 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 filter set 100 into clips provided by the housing 22 of the PD machine or cycler 20. As shown in FIG. 2, the short tubing 108 is initially fitted with a cap 114b so that when the patient line connector 56 or filter set 100 is clipped into the housing 22, the short tubing 108 hangs down from the filter set 100 and is closed off to the environment via the cap 114b. Next, control unit 40 causes PD fluid pump 24 to prime fresh PD fluid into fresh PD fluid lumen 52 with fresh PD fluid valve 26a open and spent PD fluid valve 26b closed, up to filter membranes 120a, 120b, where air is forced out of vent opening 106o.

[0100] Once the fresh PD fluid lumen 52 is fully primed, the pressure sensors 28a and 28b detect a pressure rise because there is no place for the fresh PD fluid to keep the spent PD fluid valve 26b closed. Seeing the pressure rise, with the filter membranes 120a, 120b now fully wetted, the control unit 40 opens the spent PD fluid valve 26b, allowing the PD fluid pump 24 to push fresh PD fluid through the hydrophilic filter membranes 120a, 120b and into the inner compartment 106i, which pushes air through the inner compartment, into the spent PD fluid tube 106u and into a portion of the spent PD fluid lumen 54. Thus, air is forced up the spent PD fluid lumen 54 towards the system drain. Now, the control unit 40 can be programmed to know and actuate several known volumetric strokes of the PD fluid pump 24 required to properly prime the inner compartment 106i, the spent PD fluid tube 106u, and the desired portion of the spent PD fluid lumen 54. At this point, the body 106 of the filter set 100 is fully primed. It should be appreciated that it is not necessary to clamp the filter set 100 to the housing 22 to perform the above-described priming of the body 106 of the filter set 100, although doing so may help prevent kinking of the dual lumen patient line 50 during such priming.

[0101] The user interface 48 of the PD machine or cycler 20 then audibly, visually or audibly prompts the patient P to remove the filter set 100 from the clip on the housing 22, remove the cap 114b from the short tube 108, connect the short tube 108 to the patient transfer set 58 and open the clamp on the patient 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 (possibly closed), causes the PD fluid pump 24 to draw spent PD fluid from the patient to prime the short tube 108, pulling air from the short tube, through the spent PD fluid tube 106u, up the spent PD fluid lumen 54 of the dual lumen patient line 50 and towards the drain of the PD machine or cycler 20. Such drawing of spent PD fluid may be part of the initial drain of the patient. Thus, the amount of spent PD fluid removed from the patient, in one embodiment, is counted by control unit 40 (e.g., 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 body 106 of filter set 100, control unit 40 may or may not draw effluent from the patient to fully prime short tube 108 before beginning the initial patient fill. That is, it is contemplated that control unit 40 may allow a small amount of air present in short tube 108 to be pushed back into the patient. However, if control unit 40 draws an initial amount of effluent from the patient to prime short tube 108, control unit 40 may count the amount of effluent drawn from the patient (e.g., by accumulating known volumetric strokes of PD fluid pump 24) as part of the subsequent initial drain.

[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 audibly 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 cap 114b at the end of the short tubing 108 in the example above. With the patient transfer set clamp closed, the control unit 40 primes fresh PD fluid using the PD fluid pump 24 through the fresh PD fluid lumen 52, the filter set body 106, and a portion of the spent PD fluid lumen 54, 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 actuates valves 26a and 26b and pump 24 as described above to draw spent PD fluid from the peritoneal cavity of patient P and prime short tubing 108 and spent PD fluid tubing 106u with patient effluent. The effluent priming of short tubing 108 may also 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 remove from the patient at the start of treatment. This is true in many cases where the patient is full of spent PD fluid at the start of 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 start of treatment. It is believed 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 knows when to start the next treatment when the patient is in a dry state with no or very little PD fluid used. Here, instead of attempting to completely drain the patient with the final drain of the previous treatment, the control unit 40 will allow an amount of effluent remaining in the patient's peritoneal cavity after treatment. The residual amount may be, for example, 50 milliliters ("ml") or more, as necessary, to ensure that the patient's indwelling PD catheter has access to the residual effluent. The residual amount must be sufficient to prime any air through the proximal end of the short tube 108 at least at the junction of the filter set 100.

[0106] The above priming procedure is advantageous for several reasons. First, it eliminates the step of placing the patient clip patient line connector 56 into the clip provided by the housing 22 of the PD machine or cycler 20. It also eliminates the need for the patient line connector 56 to be fitted with a vent cap and / or for the housing 22 of the PD machine or cycler 20 to have a sensor to detect when fresh PD fluid has reached the patient line connector 56. Both savings reduce cost and complexity. Second, after a procedure, the patient disconnects the transfer set side connector 110 from the patient transfer set 58 and then seals the transfer set 58 with a cap (not shown) that has 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 side connector 110 of a new filter set 100 at the start of the next procedure. 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 delivering the residual disinfectant to the patient, thereby preventing health issues for particularly sensitive patients.

[0107] 2-5, a gasket 112, such as silicone or polyvinyl chloride ("PVC") rubber, is mated to the fresh and used PD fluid ports 104f, 104u of the lumen side connector 104 of the filter housing 102. In one embodiment, the gasket 112 provides a dual seal with the mating patient line connector 56. The patient line connector 56 includes fresh and used ports (not shown) that extend into the fresh and used PD fluid ports 104f, 104u, respectively, of the lumen side connector 104. The gasket 112 provides fresh and used port seals 112f, 112u between the mating fresh and used PD fluid ports of the patient line connector 56 and the fresh and used ports 104f, 104u of the lumen side connector 104. The port seals 112f, 112u as well as the fresh and used ports of the patient line connector 56 may be tapered to narrow as they extend into the filter housing 102. The port seals 112f, 112u provide a first seal for the patient line connector 56. The patient line connector 56 also includes a flange having a raised continuous rib that extends around the flange (not shown). The flange and rib translate towards the flange portion 112l of the gasket 112 when the patient line connector 56 is connected to the lumen side connector 104. When the patient line connector 56 is fully connected to the lumen side connector 104, the raised rib extends into the deformable flange portion 112l of the gasket 112, which compresses around the raised rib to form a second seal between the lumen side connector 104 and the patient line connector 56.

[0108] Spent PD fluid removed through the patient transfer set 58 travels under negative pressure through the filter set 100 via spent PD fluid tubing 106u (thus bypassing filter membranes 120a, 120b) and back through the spent PD fluid lumen 54 of the dual lumen patient line 50 to the machine or cycler 20. The machine or cycler 20 pumps the spent PD fluid under positive pressure to drain via drain line 60. The machine or cycler 20 includes a pressure sensor 28b located along the spent PD fluid side of its internal tubing to measure the negative pressure applied to the spent PD fluid by the PD fluid pump 24 in the patient drain. That same pressure sensor 28b can be used during patient fill to measure the positive pump pressure (through the spent PD fluid tubing 106u of the filter set 102 and the spent PD fluid lumen 54 of the patient line 50 back to the pressure sensor 28b), which is desirable because the measured pressure is the pressure of the fresh PD fluid downstream (after filtration) of the filter membranes 120a, 120b. The measured pressure therefore takes into account any pressure drop across the filter membranes 120a, 120b and more accurately reflects the pressure at which the PD fluid is being delivered to the patient P.

[0109] 7A and 7B, an alternative embodiment of a filter set 100 is shown. The filter set 100 of FIG. 7A and 7B includes many of the same features as the filter set 100 of FIG. 2-6, which are numbered the same, including all of the structure, function and alternatives previously described therefor. The filter set of FIG. 100, FIG. 7A and 7B, includes a lumen connector 104 having a fresh port 104f and a used port 104u surrounded by a threaded shroud 104s. The lumen connector 104 is connected to or molded into a capped body 106 via lids 106a, 106b which, together with the outer surfaces of flat sheet hydrophilic filter membranes 120a, 120b, form first and second outer compartments 106e, 106f, respectively. 7A shows that fresh PD fluid is delivered through the fresh PD fluid passageway 116 and pressurized within the first and second outer compartments 106e, 106f for further filtration through filter membranes 120a, 120b. The further filtered fresh PD fluid flows into the inner compartment 106i of the body 106 and from there through the transferset port 106p to the patient. One difference from the illustrated filter set 100 is that in FIGS. 7A and 7B the transferset port 106p is surrounded by a threaded shroud 106z that mates with a short tube 108 or mating connector for the patient's transfer set 58.

[0110] Figure 7B illustrates a key difference from filter set 100 of Figures 7A and 7B, namely, that spent PD fluid tubing 106u is not provided, but instead the spent PD fluid flows from transferset side port 106p, through inner compartment 106i, between and around a series of ribs 106r, and out spent PD fluid passageway 118 of lumen side connector 104 and spent PD fluid port 104u to spent PD fluid lumen 54 of patient line 50. The spent PD fluid may tangentially contact the inner surfaces of filter membranes 120a, 120b. The primary mechanism that prevents spent PD fluid from entering fresh PD fluid passageway 116 (during patient drain) and fresh PD fluid from entering spent PD fluid passageway 118 (during patient fill) is the fact that (i) fresh PD fluid lumen 52 is closed or occluded by machine or cycler 20 during patient drain, and (ii) spent PD fluid lumen 54 is closed or occluded by machine or cycler 20 during patient fill. Thus, even if spent PD fluid were to try to flow through membrane filters 120a, 120b and fresh PD fluid passageway 116 into patient drain, there would be no place for the spent PD fluid to flow because the pressure in fresh PD fluid lumen 52 is equalized. Also, even if fresh PD fluid were to bend to flow backwards through spent PD fluid passageway 118 during patient fill, there would be no place for the fresh PD fluid to flow because the pressure in spent PD fluid lumen 54 is equalized.

[0111] 8A and 8B show suitable lids 106a, 106b for ultrasonic sealing, heat sealing, solvent bonding, laser welding, or sealing via UV curable adhesive to the body 106 of the filter set 100 of any of FIGS. 2-6 or 7A, 7B. Here, to prevent accidental blockage of the vent opening 106o provided by the lids 106a, 106b, a protective mechanism such as a rib 106n or other raised structure is provided along one or both sides of the vent opening 106o, so that air can vent from the interior of the body 106 through the vent opening 106o, for example, via the hydrophobic membranes 122a, 122b, 122c, 122d, even when a patient is lying on the filter set 100. The protective rib 106n to this end creates an air path between the lids 106a, 106b and the exterior surface that the lids contact when a patient is lying on the filter set 100.

[0112] 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 of such modifications and alterations 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 a check valve for directing fresh and used PD fluids to desired locations within the set. Also, while the hydrophilic filter membranes 120a, 120b are described in one embodiment as having a pore size of about 0.2 microns, one or both of the filter membranes 120a, 120b may alternatively or additionally include a charged membrane for endotoxin reduction. Furthermore, although two filter membranes 120a, 120b are shown, the system 10 may alternatively use a single filter membrane or three or more filter membranes 120a-120n.

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 a filter set (100) including first and second filter membranes (120a, 120b) separated by an inner compartment (106i) through which fresh PD fluid is filtered by the first and second filter membranes (120a, 120b) before exiting the filter set (100); the filter set (100) further includes a spent PD fluid tube (106u) positioned and arranged to transport spent PD fluid through the at least one filter membrane (120a, 120b) without contacting the at least one filter membrane (120a, 120b), the spent PD fluid tube (106u) extending through the inner compartment (106i).

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. 4. The PD system of claim 3, wherein the filter set includes a compressible gasket configured to seal the fresh and used PD fluid ports to a patient line connector located at the end of the dual lumen patient line.

6. The PD system (10) of claim 1, comprising at least one rib (106r) located within the inner compartment (106i) for supporting the first and second filter membranes (120a, 120b).

7. 2. The PD system (10) of claim 1, wherein the filter set (100) includes a transfer set side port (106p) through which fresh and used PD fluid flows, and the used PD fluid tube (106u) extends into the transfer set side port (106p).

8. 8. The PD system (10) of claim 7, wherein the transfer set side port (106p) defines an internal stopper (106t) against which a tube (108) can be abutted, the internal stopper (106t) extending into the transfer set side port (106p) spaced from the end of the used PD fluid tube (106u).

9. 2. The PD system of claim 1, wherein the filter set includes at least one outer compartment dimensioned to move the fresh PD fluid across an upstream side of the at least one filter membrane.

10. The PD system (10) of claim 9, wherein the at least one filter membrane (120a, 120b) is a flat sheet filter membrane.

11. 10. The PD system of claim 9, wherein the filter set includes a deflector wall positioned and arranged to move incoming fresh PD fluid toward the at least one outer compartment.

12. 10. The PD system of claim 9, wherein the filter set includes at least one lid that cooperates with the at least one filter membrane to form the at least one outer compartment.

13. 13. The PD system (10) of claim 12, wherein the at least one lid (106a, 106b) includes at least one vent opening (106o) and at least one hydrophobic membrane (122a, 122b, 122c, 122d) sealingly covering the at least one vent opening (106o).

14. 13. The PD system (10) of claim 12, wherein the filter set (100) includes at least one side wall (106s), the at least one lid (106a, 106b) is sealed to an outer portion of the at least one side wall (106s), and the at least one filter membrane (120a, 120b) is sealed to an inner portion of the at least one side wall (106s).

15. 10. The PD system of claim 1, wherein the filter set is configured to connect directly to a patient's transfer set, or the filter set includes a flexible tube configured to connect to the patient's transfer set.

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