Peritoneal dialysis patient line with sterile filter and drain diversion

Abstract

To provide a peritoneal dialysis patient line with a suitable sterilizing filter and a drain bypass.SOLUTION: A medical fluid treatment system includes: a source of purified water; at least one concentrate for mixing with the water from the source to form a treatment fluid; a disposable set including a pumping portion, a concentrate line in fluid communication with the concentrate source and the pumping portion, and a patient line in fluid communication with the pumping portion, the patient line including a filter having a membrane configured to filter the treatment fluid, the filter being configured such that (i) fresh treatment fluid flowing from the pumping portion towards a patient flows through the membrane and (ii) used treatment fluid flowing through the filter from the patient to the pumping portion bypasses the membrane; and a medical fluid delivery machine including a pump actuator operable with the pumping portion of the disposable set.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (Related Applications) This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62 / 732,782, filed Sep. 18, 2018, and entitled "PERITONEAL DIALYSIS PATIENT LINE WITH STERILIZING FILTER AND DRAIN BYPASS," which is incorporated by reference in its entirety. [Background technology]

[0002] The present disclosure relates generally to medical fluid devices and, more particularly, to medical fluid devices that mix fluids online for treatment or that receive fluids to be mixed online for treatment.

[0003] Due to a variety of causes, an individual's renal system may fail. Renal failure produces several physiological disturbances: it is no longer possible to maintain fluid and mineral balance or to excrete the daily metabolic load. Toxic end products of metabolism, such as urea, creatinine, uric acid, and others, may accumulate in the patient's blood and tissues.

[0004] Reduced kidney function, especially renal failure, is treated with dialysis. Dialysis removes waste products, toxins, and excess water from the body that would otherwise be removed by normally functioning kidneys. Dialysis treatment for replacement of kidney function is important for many people because the treatment can be 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 dialysate, 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 a substitute or replacement fluid to the extracorporeal circuit during treatment. The substitute fluid, and fluid accumulated by the patient during treatment, is ultrafiltered over the course of HF treatment, providing a convective transport mechanism that is particularly beneficial in removing medium and large molecules.

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

[0008] Most HD (HF, HDF) treatments occur in centers. There is currently a trend toward home hemodialysis ("HHD"), in part because HHD may offer therapeutic benefits compared to ambulatory hemodialysis treatments, which are performed daily and typically occur once every two or three weeks. Studies have shown that more frequent treatments remove more toxins and waste products than patients who receive less frequent, but perhaps longer, treatments. Patients who receive more frequent treatments do not suffer as many down cycles as ambulatory patients who have accumulated two or three days' worth of toxins prior to treatment. In some areas, the nearest dialysis center is many miles from the patient's home, causing door-to-door treatment times to consume a large portion of the day. HHD can be performed overnight or during the day while the patient is relaxing, working, or otherwise productive.

[0009] Another type of renal failure therapy is peritoneal dialysis ("PD"), in which a dialysis solution, also called dialysate, is infused into the patient's peritoneal cavity via a catheter. The dialysate contacts the peritoneal membrane of the peritoneal cavity. Waste, toxins, and excess water pass from the patient's bloodstream through the peritoneal membrane into the dialysate due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. Osmotic agents in the PD dialysate provide the osmotic gradient. Spent or exhausted dialysate is pumped out of the patient, removing waste, toxins, and excess water from the patient. This cycle is 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. Here, the patient manually connects an implanted catheter to a drain tube, allowing used or exhausted dialysate to drain from the peritoneal cavity. The patient then switches the fluid communication so that the patient catheter communicates with a bag of fresh dialysate and infuses fresh dialysate through the catheter and into the patient. The patient disconnects the catheter from the fresh dialysate bag, allowing the dialysate to dwell in the peritoneal cavity, and transfer of waste, toxins, and excess water occurs. After a dwell cycle, 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] Automated peritoneal dialysis ("APD") is similar to CAPD in that the dialysis treatment includes drain, fill, and dwell cycles. However, APD machines perform the cycles automatically, typically while the patient sleeps. APD machines relieve the patient from having to perform the treatment cycles manually and from having to transport supplies during the day. APD machines fluidly connect to an implanted catheter, to a fresh dialysate source or bag, and to a fluid drain. The APD machine pumps fresh dialysate from the dialysate source through the catheter and into the patient's peritoneal cavity. APD machines also allow the dialysate to dwell within the cavity and for transfer of waste, toxins, and excess water to occur. The source may include multiple sterile dialysate solution bags.

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

[0013] In any of the above therapeutic methods using automated machines, the therapeutic fluid may be prepared, for example, online, before and / or during the treatment, or at the point of use. It is important that the fluid is properly purified before it is used for treatment or delivered to the patient. Thus, there is a need for improved online or point of use systems that ensure that the fluid being prepared is of sufficient quality. Summary of the Invention [Means for solving the problem]

[0014] Examples described herein disclose automated systems and methods applicable to fluid delivery for, for example, peritoneal dialysis ("PD"), plasma exchange, hemodialysis ("HD"), hemofiltration ("HF"), hemodiafiltration ("HDF"), continuous renal replacement therapy ("CRRT"), apheresis, autologous blood transfusion, hemofiltration for sepsis, and extracorporeal membrane oxygenation ("ECMO") therapies. The systems and methods described herein are applicable to any medical fluid delivery system in which treatment fluid may be made, for example, immediately prior to and / or during treatment, online, or at the point of use. These therapies may be referred to herein collectively or generally individually as medical fluid delivery systems.

[0015] Additionally, the systems and methods described herein may each be used in conjunction with clinical or home care. For example, the systems and methods may be employed with in-center PD, HD, HF, or HDF machines that are activated throughout the day. Alternatively, the systems and methods may be used in conjunction with home PD, HD, HF, or HDF machines that are generally operated at the patient's convenience.

[0016] In one embodiment, a peritoneal dialysis system and method with point-of-use dialysate generation is provided. The system includes a circulator and a water purifier. The circulator includes a control unit having at least one processor and at least one memory. The circulator may further include a wired or wireless transceiver for transmitting information to and receiving information from the water purifier. The water purifier may also include a control unit having at least one processor and at least one memory, and a wired or wireless transceiver for transmitting information to and receiving information from the control unit of the circulator.

[0017] The circulator includes a device that is programmed via its control unit to prepare fresh dialysis solution at the point of use, pump the freshly prepared dialysate to the patient, allow the dialysate to dwell in the patient, and then pump the spent dialysate to drain. The circulator includes, in one embodiment, a heater under the control of the control unit for heating the dialysate as it is mixed. The heater may be located, for example, on top of the circulator housing, for example under a heated lid.

[0018] The circulation device (and in one embodiment, the water purifier) ​​operates with a disposable set. The disposable set may include a disposable pump cassette, which may be constructed from a planar rigid plastic part covered on one or both sides by a flexible membrane to form a fluid pump and valve chamber. The fluid pump chamber may operate with a pneumatic pump chamber of the circulation device, while the fluid valve chamber operates with a pneumatic valve chamber of the circulation device.

[0019] The disposable set may include (i) a patient line extending from the cassette to a patient line connector, (ii) a drain line extending from the cassette to a drain line connector (which may then be removably connected to a water purifier), (iii) a heater / mixing line extending from the pump cassette to a heater / mixing bag of the present disclosure, (iv) an upstream water line section extending from the water purifier to a water inlet of the water accumulator, and a downstream water line section extending from the water outlet of the water accumulator to the cassette, (v) a final bag or sample line extending from the cassette to a premixed final fill bag of dialysis fluid or to a sample bag or other sample collection container, (vi) a first, e.g., glucose concentrate line extending from the cassette to a first, e.g., glucose concentrate container, and / or (vii) a second, e.g., buffer concentrate line extending from the cassette to a second, e.g., buffer concentrate container.

[0020] The patient line of the present disclosure, in one embodiment, connects to a single lumen catheter that extends into the patient's peritoneal cavity. During treatment, fresh peritoneal dialysis fluid is infused into the patient's peritoneal cavity through the catheter and allowed to dwell for a period of time, for example, about 4 hours. During that period of time, toxins osmotically migrate through the patient's peritoneal wall lining the patient's peritoneal cavity into the dialysis fluid, removing toxins from the patient's blood. The spent dialysis fluid (also called effluent) is then drained back through the patient line and discarded. If the dialysis solution contains contaminants upon infusion, the patient may suffer complications. One source of contaminants occurs upon making disposable sets and tubing connections, for example, when the patient or caregiver touches the connection and / or does not properly disinfect the connector upon disconnection.

[0021] To combat the contaminants described above, it is contemplated to install a filter in the patient line along a single lumen pathway that filters the dialysis solution prior to infusion into the patient. The filter is provided in a housing that allows the spent dialysate or effluent draining from the patient through the same patient line to bypass the filter membrane of the filter, preventing (i) clogging of the filter and (ii) the filter filtering out toxins or other substances from the effluent that may then be reinfused back into the patient with fresh dialysate through the same patient line in the next infusion cycle.

[0022] In one embodiment, the filter housing is configured such that parallel fluid paths are created within the housing. A fresh dialysate path through one or more membranes of the filter is provided to deliver filtered fresh dialysate to the patient. Spent dialysate, on the other hand, flows through the filter housing via a different parallel path that bypasses one or more membranes of the filter. In one embodiment, the parallel paths are supported using a pair of one-way or check valves (such as duckbill check valves). A first one-way valve is installed at the fresh dialysate exit end of the fresh dialysate path of the housing. The first check valve is oriented to block the incoming spent dialysate and to allow fresh dialysate flowing through the fresh dialysate path to exit the filter housing and flow to the patient. A second one-way valve is installed at the spent dialysate exit end of the spent dialysate path of the housing. The second one-way valve is oriented to block the incoming fresh dialysate and to allow the spent dialysate flowing through the spent dialysate pathway to exit the filter housing and flow to the pump cassette of the disposable set where it is pumped to discharge.

[0023] Fresh dialysate flowing through the fresh dialysate pathway, in one embodiment, flows through a line membrane housing. The membrane housing may include a spacer having a rectangular grid of passages extending vertically from the upper and lower external membrane surfaces into rectangular gap passages located adjacent the grid, the gaps leading to the exit pathway of the filter housing. In one embodiment, the filter membrane is a hydrophilic material with micropores that allow purified fluid to pass through but trap contaminants. When the hydrophilic filter membrane is wetted, the membrane prevents air from passing through.

[0024] In one embodiment, two rectangular filter membranes are sealed to form the upper and lower surfaces of the membrane housing, respectively. Fresh fluid enters the filter and then splits into two fresh dialysate flows or branches: one flow or branch that flows over the top of the upper membrane, and another flow or branch that flows under the bottom of the lower filter membrane. The upper flow flows downward through the upper membrane into the spacer grid, then out of the filter housing's exit path through the one-way valve to the patient. The lower flow flows upward through the lower membrane into the spacer grid of the membrane housing, then out of the filter's exit path through the fresh dialysate one-way valve to the patient. The same fresh fluid check valve is oriented to prevent the spent dialysate exiting the patient from flowing backwards back through the filter membrane. The spent dialysate path instead bypasses the membrane housing entirely.

[0025] At the end of the patient dwell phase, the dialysis machine or circulator applies negative pressure along the patient line to pull spent dialysate from the patient. Again, a check valve at the end of the fresh dialysate pathway prevents the effluent from flowing into the interior region of the membrane housing and out through the membrane. Instead, a one-way valve redirects the effluent to bypass the filter membrane and instead flow along the spent dialysate pathway formed within the filter housing, which extends along the side of the membrane housing. The effluent flow is directed to the pump cassette, as described above.

[0026] The filter construction just described leads to a method of filtration that includes preparing a medical solution, such as a dialysis solution, for treatment, delivering the treatment fluid along a patient line through a filter membrane to a patient, and returning spent solution through the same patient line, but bypassing the filter membrane, where bypassing the filter membrane may include doing so while still flowing spent solution through the overall housing of the filter.

[0027] Placing a sterile filter in the patient line has several advantages. First, the location is immediately prior to the medical fluid reaching the patient, such that any contaminants present in the disposable set, e.g., due to set conditions, will be removed from the medical fluid, except for contaminants located in the short section of tubing leading from the filter to the patient. Second, the filter is located after mixing, such that the filter will remove any contaminants provided via one or more concentrates used to generate the on-line medical fluid. Third, there is a high probability that there is a clean, unobstructed portion of the patient line extending from the pump or pressure providing portion of the disposable set to the filter, making it easily available for pressure testing of the filter membrane prior to delivery to the patient.

[0028] Although the subject matter of the present disclosure will be described in connection with peritoneal dialysis, it should be understood that the present disclosure is applicable to other medical fluid applications, such as other types of dialysis applications, substitute fluid applications, or intravenous ("IV") infusion pump applications, where the infusion or treatment solution is as devoid of contaminants as possible.

[0029] In light of the disclosure herein, and which may be combined with any other aspects recited herein unless otherwise specified without limiting the disclosure in any way, in a first aspect of the disclosure, a dialysis system includes a medical fluid treatment system including a disposable set including a purified water source, at least one concentrate for mixing with water from the source to form a treatment fluid, a pump portion, a concentrate line in fluid communication with the concentrate source and the pump portion, and a patient line in fluid communication with the pump portion, the patient line including a filter having a membrane configured to filter the treatment fluid, the filter configured such that (i) fresh treatment fluid flowing from the pump portion towards the patient flows through the membrane, and (ii) spent treatment fluid flowing from the patient through the filter to the pump portion bypasses the membrane; and a medical fluid delivery machine including a pump actuator operable with the pump portion of the disposable set.

[0030] In a second aspect of the disclosure, which may be combined with any other aspect recited herein unless otherwise specified, the therapy fluid is a peritoneal dialysis therapy fluid.

[0031] In a third aspect of the disclosure, which may be combined with any other aspect recited herein unless otherwise specified, a filter includes a fresh treatment fluid pathway and a spent treatment fluid pathway installed parallel to the fresh treatment fluid pathway, a membrane is located along the fresh fluid pathway, and the spent treatment fluid pathway allows the spent treatment fluid flowing through the filter to bypass the membrane.

[0032] In a fourth aspect of the disclosure, which may be combined with the third aspect in combination with any other aspect enumerated herein unless otherwise specified, a one-way valve is located at the exit end of the fresh treatment fluid pathway, the one-way valve positioned and arranged to prevent spent treatment fluid returning from the patient from reaching the membrane.

[0033] In a fifth aspect of the present disclosure, which may be combined with the third aspect in combination with any other aspect enumerated herein unless otherwise specified, a one-way valve is located at an exit end of the spent treatment fluid pathway, the one-way valve positioned and arranged to prevent fresh treatment fluid from flowing through the filter via the spent treatment fluid pathway.

[0034] In a sixth aspect of the present disclosure, which may be combined with the third aspect in combination with any other aspect enumerated herein unless otherwise specified, the membrane is housed within a membrane housing located along the fresh fluid pathway, and the filter is configured such that the fresh treatment fluid flows from outside the membrane housing through the membrane and into the interior region of the membrane housing.

[0035] In a seventh aspect of the present disclosure, which may be combined with the third aspect in combination with any other aspect enumerated herein unless otherwise specified, a filter includes a housing having a first port and a second port, the first port opening into a first end of the filter housing and the second port opening into a second end of the filter housing, the first end of the filter housing forming a first end of a fresh and spent treatment fluid pathway, and the second end of the filter housing forming a second end of the fresh and spent treatment fluid pathway.

[0036] In an eighth aspect of the present disclosure, which may be combined with the seventh aspect in combination with any other aspect enumerated herein unless otherwise specified, a first end of the fresh fluid treatment pathway at a first end of the filter housing includes a first one-way valve and a second end of the spent fluid treatment pathway at a second end of the filter housing includes a second one-way valve.

[0037] In a ninth aspect of the present disclosure, which may be combined with any other aspect recited in this specification unless otherwise specified, the membrane is housed within a membrane housing, and fresh treatment fluid entering the filter flows to the outside of the membrane housing and fresh treatment fluid exiting the filter flows from the inside of the membrane housing.

[0038] In a tenth aspect of the present disclosure, which may be combined with any other aspect recited herein unless otherwise specified, the membrane is a first membrane, the filter includes a second membrane, the first and second membranes are contained within a membrane housing, and fresh treatment fluid entering the filter is split into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane.

[0039] In an eleventh aspect of the present disclosure, which may be combined with the tenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the membrane housing includes a grid of passages located between the first membrane and the second membrane.

[0040] In a twelfth aspect of the present disclosure, which may be combined with the tenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the first and second membranes are located on opposite sides of the membrane housing, respectively, and the first branch extends to the first side of the housing and the second branch extends to the second side of the housing.

[0041] In a thirteenth aspect of the present disclosure, which may be combined with any other aspect recited herein unless otherwise specified, (i) the pump actuator operable with the pump portion of the medical fluid delivery machine includes a pneumatic pump actuator and the pump portion of the disposable set includes a pump membrane, or (ii) the pump actuator operable with the pump portion of the medical fluid delivery machine includes a peristaltic pump actuator and the pump portion of the disposable set includes a peristaltic pump tube.

[0042] In a fourteenth aspect of the present disclosure, which may be combined with any other aspect recited herein unless otherwise specified, a medical fluid treatment system includes at least one hydrophobic vent for removing air from a filter.

[0043] In a fifteenth aspect of the present disclosure, which may be combined with any other aspect recited herein unless otherwise specified, a disposable set for a medical fluid therapy system includes a pump portion, a concentrate line in fluid communication with the pump portion, and a patient line in fluid communication with the pump portion, the patient line including a filter having a membrane configured to filter therapy fluid, the filter configured such that (i) fresh therapy fluid flowing from the pump portion toward the patient flows through the membrane, and (ii) spent therapy fluid flowing from the patient to the pump portion through the filter bypasses the membrane via a one-way valve positioned and arranged to open under fresh therapy fluid pressure and close under spent therapy fluid pressure.

[0044] In a sixteenth aspect of the present disclosure, which may be combined with the fifteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the one-way valve comprises a duckbill check valve.

[0045] In a seventeenth aspect of the present disclosure, which may be combined with the fifteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the one-way valve is a first one-way valve and includes a second one-way valve positioned at a second end of the filter opposite a first end of the filter at which the first one-way valve is positioned, the second one-way valve being positioned and arranged to open under spent treatment fluid pressure and close under fresh treatment fluid pressure.

[0046] In an eighteenth aspect of the present disclosure, which may be combined with any other aspect recited herein unless otherwise specified, a filter intended for fluid flow in a first and second direction, the filter configured to filter fluid flowing in the first direction and not filter fluid flowing in the second direction, includes a housing, a first fluid path provided by the housing for fluid flow in the first direction, a second fluid path provided by the housing for fluid flow in the second direction, a membrane positioned to filter fluid flowing in the first direction, and a one-way valve located at an exit end of the first fluid path, the one-way valve positioned and arranged to prevent fluid flowing in the second direction from reaching the membrane.

[0047] In a nineteenth aspect of the present disclosure, which may be combined with the eighteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the filter is part of a disposable set including a fluid line connected to the filter and a pump portion for operation with a pump actuator, the pump portion in fluid communication with the fluid line.

[0048] In a twentieth aspect of the present disclosure, which may be combined with the nineteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the pump portion is part of a disposable cassette of the disposable set, and the fluid lines extend from the disposable cassette to the filter.

[0049] In a twenty-first aspect of the present disclosure, which may be combined with the nineteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the filter is configured to fluidly connect a fluid line at different times to a first fluid path and a second fluid path of the filter.

[0050] In a twenty-second aspect of the present disclosure, which may be combined with the nineteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the fluid line is a first fluid line and the disposable set includes a second fluid line connected to a filter, the second fluid line for extending to a fluid delivery destination.

[0051] In a twenty-third aspect of the present disclosure, which may be combined with the eighteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the one-way valve is a first one-way valve and includes a second one-way valve located at an exit end of a second fluid pathway, the second one-way valve positioned and arranged to prevent fluid flowing in the first direction from flowing through the second fluid pathway.

[0052] In a twenty-fourth aspect of the present disclosure, which may be combined with the twenty-third aspect in combination with any other aspect enumerated herein unless otherwise specified, the housing includes (i) a first port located downstream from the first one-way valve and in fluid communication with the second fluid path, and (ii) a second port located downstream from the second one-way valve and in fluid communication with the first fluid path.

[0053] In a twenty-fifth aspect of the present disclosure, which may be combined with the eighteenth aspect in combination with any other aspect enumerated herein unless otherwise specified, the membrane is contained within a membrane housing located within the filter housing and along a first fluid path, and the filter housing is configured such that fluid flowing in a first direction flows from outside the membrane housing through the membrane into an interior region of the membrane housing.

[0054] In a twenty-sixth aspect of the present disclosure, which may be combined with the twenty-fifth aspect in combination with any other aspect enumerated herein unless otherwise specified, fluid flowing in a first direction exits the filter from an interior region of the membrane housing, and fluid flowing in a second direction bypasses the membrane housing via a second fluid path.

[0055] In a twenty-seventh aspect of the present disclosure, which may be combined with the twenty-fifth aspect in combination with any other aspect enumerated herein unless otherwise specified, the membrane is a first membrane and includes a second membrane, the first and second membranes are contained within a membrane housing, and a fluid flowing in a first direction is divided into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane.

[0056] In a twenty-eighth aspect of the present disclosure, which may be combined with the twenty-seventh aspect in combination with any other aspect enumerated herein unless otherwise specified, the membrane housing includes a grid of passages located between the first membrane and the second membrane.

[0057] In a twenty-ninth aspect of the present disclosure, which may be combined with the twenty-seventh aspect in combination with any other aspect enumerated herein unless otherwise specified, the first and second membranes are each located on opposite sides of the membrane housing, the first branch extending to the first side of the membrane housing and the second branch extending to the second side of the membrane housing.

[0058] In a 30th aspect of the present disclosure, which may be combined with the 18th aspect in combination with any other aspect enumerated herein unless otherwise specified, the housing includes a hydrophobic vent for air removal.

[0059] In a thirty-first aspect of the present disclosure, which may be combined with any other aspect recited in this specification unless otherwise specified, a medical fluid treatment method includes steps of enabling preparation of a medical fluid at the point of use for treatment, enabling delivery of the medical fluid along a patient line to a patient through a filter membrane, and enabling return of the used medical fluid through the same patient line in which the filter membrane is bypassed.

[0060] In a thirty-second aspect of the present disclosure, which may be combined with the thirty-first aspect in combination with any other aspect enumerated herein unless otherwise specified, the filter membrane and the bypass occur within a filter that houses the filter membrane.

[0061] In a thirty-third aspect of the present disclosure, which may be combined with the thirty-first aspect in combination with any other aspect enumerated herein unless otherwise specified, the medical fluid prepared at the point of use for treatment is a peritoneal dialysis fluid.

[0062] In a thirty-fourth aspect of the present disclosure, which may be combined with any other aspect recited in this specification unless otherwise specified, a fluid filtering method includes allowing fluid flowing from a first port of a filter to a second port of the filter to be filtered, and allowing fluid flowing from the second port of the filter to the first port of the filter to bypass the filtration.

[0063] In a thirty-fifth aspect of the present disclosure, which may be combined with the thirty-fourth aspect in combination with any other aspect enumerated herein unless otherwise specified, allowing fluid flowing from the second port of the filter to the first port of the filter to bypass filtration includes redirecting fluid flowing from the second port to the first port of the filter away from the filtration mechanism.

[0064] In a thirty-sixth aspect of the present disclosure, which may be combined with the thirty-fourth aspect in combination with any other aspect enumerated herein unless otherwise specified, the method further includes a step of allowing fluid flowing from the first port of the filter to the second port of the filter to bypass a fluid path used by fluid flowing from the second port of the filter to the first port of the filter.

[0065] In a thirty-seventh aspect of the present disclosure, any of the structures, functionality, and alternatives disclosed in connection with Figures 1-6 may be combined with any of the other structures, functionality, and alternatives disclosed in connection with Figures 1-6.

[0066] In light of the present disclosure and the above aspects, it is therefore an advantage of the present disclosure to provide an improved medical fluid delivery system.

[0067] It is another advantage of the present disclosure to provide an improved medical fluid delivery system that prepares therapeutic fluids on-line or at the point of use.

[0068] It is yet another advantage of the present disclosure to provide an improved medical fluid delivery system having a sterile, sterilizing grade filter in the patient line.

[0069] It is yet a further advantage of the present disclosure to provide an improved medical fluid delivery system having a sterile, sterilizing grade filter that filters the on-line mixed therapeutic fluid.

[0070] It is yet another advantage of the present disclosure to provide an improved medical fluid delivery system having a clean, sterilizing grade filter that is easily accessible to be purged of air and primed with liquid.

[0071] The advantages discussed herein may be found in one or some, but perhaps not all, of the embodiments disclosed herein. Additional features and advantages are described herein and will be apparent from the following detailed description and drawings. The present invention provides, for example, the following: (Item 1) 1. A medical fluid treatment system comprising: A purified water source; at least one concentrate for mixing with water from said source to form a treatment fluid; A disposable set, The pump part, a concentrate line in fluid communication with a concentrate source and said pump portion; a patient line in fluid communication with the pump portion, the patient line including a filter having a membrane configured to filter the treatment fluid, the filter configured such that (i) fresh treatment fluid flowing from the pump portion towards a patient flows through the membrane, and (ii) spent treatment fluid flowing from the patient through the filter to the pump portion bypasses the membrane; A disposable set including: a medical fluid delivery machine including a pump actuator operable with the pump portion of the disposable set; A medical fluid treatment system comprising: (Item 2) 2. The medical fluid therapy system of claim 1, wherein the therapy fluid is a peritoneal dialysis therapy fluid. (Item 3) 3. The medical fluid treatment system of claim 1, wherein the filter includes a fresh treatment fluid pathway and a spent treatment fluid pathway disposed parallel to the fresh treatment fluid pathway, the membrane being located along the fresh fluid pathway, and the spent treatment fluid pathway allowing the spent treatment fluid flowing through the filter to bypass the membrane. (Item 4) 4. The medical fluid treatment system of claim 3, wherein a one-way valve is located at an exit end of the fresh treatment fluid pathway, the one-way valve positioned and arranged to prevent spent treatment fluid returning from the patient from reaching the membrane. (Item 5) 4. The medical fluid treatment system of claim 3, wherein a one-way valve is located at an exit end of the spent treatment fluid pathway, the one-way valve positioned and arranged to prevent fresh treatment fluid from flowing through the filter via the spent treatment fluid pathway. (Item 6) 6. The medical fluid treatment system of any of items 3-5, wherein the membrane is housed within a membrane housing located along the fresh fluid pathway, and the filter is configured such that fresh treatment fluid flows from outside the membrane housing through the membrane into an interior region of the membrane housing. (Item 7) 7. The medical fluid treatment system of any of items 3-6, wherein the filter includes a housing having a first port and a second port, the first port opening into a first end of the filter housing and the second port opening into a second end of the filter housing, the first end of the filter housing forming a first end of the fresh and spent treatment fluid pathways, and the second end of the filter housing forming a second end of the fresh and spent treatment fluid pathways. (Item 8) 8. The medical fluid treatment system of claim 7, wherein a first end of the fresh fluid treatment pathway at a first end of the filter housing includes a first one-way valve and a second end of the spent fluid treatment pathway at a second end of the filter housing includes a second one-way valve. (Item 9) 9. The medical fluid treatment system of any of claims 1-8, wherein the membrane is housed within a membrane housing, and fresh treatment fluid entering the filter flows to the outside of the membrane housing, and fresh treatment fluid exiting the filter flows from the inside of the membrane housing. (Item 10) 10. The medical fluid treatment system of any of items 1-9, wherein the membrane is a first membrane and the filter includes a second membrane, the first and second membranes are housed within a membrane housing, and fresh treatment fluid entering the filter is split into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane. (Item 11) Item 11. The medical fluid treatment system of item 10, wherein the membrane housing includes a grid of passages located between the first membrane and the second membrane. (Item 12) 12. The medical fluid treatment system of claim 10 or 11, wherein the first and second membranes are located on opposite sides of the membrane housing, the first branch extending to a first side of the housing, and the second branch extending to a second side of the housing. (Item 13) 13. The medical fluid treatment system of any of items 1-12, wherein (i) the pump actuator operable with a pump portion of the medical fluid delivery machine comprises a pneumatic pump actuator and the pump portion of the disposable set comprises a pump membrane, or (ii) the pump actuator operable with a pump portion of the medical fluid delivery machine comprises a peristaltic pump actuator and the pump portion of the disposable set comprises a peristaltic pump tube. (Item 14) 14. The medical fluid treatment system of any of claims 1-13, comprising at least one hydrophobic vent for removing air from the filter. (Item 15) 1. A disposable set for a medical fluid treatment system, the disposable set comprising: The pump part, a concentrate line in fluid communication with the pump portion; a patient line in fluid communication with the pump portion, the patient line including a filter having a membrane configured to filter a therapy fluid, the filter configured such that (i) fresh therapy fluid flowing from the pump portion towards a patient flows through the membrane, and (ii) spent therapy fluid flowing from the patient to the pump portion through the filter bypasses the membrane via a one-way valve positioned and arranged to open under fresh therapy fluid pressure and close under spent therapy fluid pressure; A disposable set that includes: (Item 16) Item 16. The disposable set of item 15, wherein the one-way valve comprises a duckbill check valve. (Item 17) 17. The disposable set of claim 15 or 16, wherein the one-way valve is a first one-way valve and includes a second one-way valve positioned at a second end of the filter opposite a first end of the filter at which the first one-way valve is positioned, the second one-way valve positioned and arranged to open under spent therapy fluid pressure and close under fresh therapy fluid pressure. (Item 18) A filter intended for fluid flow in a first and second direction, the filter being configured to filter fluid flowing in the first direction and not filter fluid flowing in the second direction, the filter comprising: A housing and a first fluid path provided by the housing for allowing fluid to flow in the first direction; a second fluid path provided by the housing for allowing fluid to flow in the second direction; and a membrane positioned to filter the fluid flowing in the first direction; and a one-way valve located at an exit end of the first fluid pathway, the one-way valve positioned and arranged to prevent fluid flowing in the second direction from reaching the membrane; A filter comprising: (Item 19) 20. The filter of claim 18, wherein the filter is part of a disposable set, the disposable set including a fluid line connected to the filter and a pump portion for operation with a pump actuator, the pump portion in fluid communication with the fluid line. (Item 20) 20. The filter of claim 19, wherein the pump portion is part of a disposable cassette of the disposable set and the fluid lines extend from the disposable cassette to the filter. (Item 21) 21. The filter of claim 19 or 20, wherein the filter is configured to fluidly communicate the fluid line at different times with the first fluid path and the second fluid path of the filter. (Item 22) 22. The filter of any of items 19-21, wherein the fluid line is a first fluid line and the disposable set includes a second fluid line connected to the filter, the second fluid line extending to a fluid delivery destination. (Item 23) 23. The filter of any of claims 18-22, wherein the one-way valve is a first one-way valve and includes a second one-way valve located at an exit end of the second fluid path, the second one-way valve positioned and arranged to prevent fluid flowing in the first direction from flowing through the second fluid path. (Item 24) Item 24. The filter of item 23, wherein the housing includes: (i) a first port located downstream from the first one-way valve and in fluid communication with the second fluid path; and (ii) a second port located downstream from the second one-way valve and in fluid communication with the first fluid path. (Item 25) 25. The filter according to any of items 18-24, wherein the membrane is housed within a membrane housing, the membrane housing being located within the filter housing and along the first fluid path, and the filter housing being configured such that fluid flowing in the first direction flows from outside the membrane housing through the membrane into an interior region of the membrane housing. (Item 26) 26. The filter of claim 25, wherein fluid flowing in the first direction exits the filter from an interior region of the membrane housing and fluid flowing in the second direction bypasses the membrane housing via the second fluid path. (Item 27) 27. The filter according to item 25 or 26, wherein the membrane is a first membrane and includes a second membrane, the first and second membranes are housed within the membrane housing, and a fluid flowing in the first direction is divided into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane. (Item 28) Item 28. The filter of item 27, wherein the membrane housing includes a grid of passages located between the first membrane and the second membrane. (Item 29) 29. The filter according to claim 27 or 28, wherein the first and second membranes are located on opposite sides of the membrane housing, respectively, the first branch extending to a first side of the membrane housing and the second branch extending to a second side of the membrane housing. (Item 30) 30. The filter of any of items 18-29, wherein the housing includes a hydrophobic vent for air removal. (Item 31) 1. A method of medical fluid treatment, comprising: Enabling preparation of medical fluids at the point of use for treatment; enabling delivery of the medical fluid along a patient line through a filter membrane to a patient; allowing return of spent medical fluid through the same patient line in which the filter membrane is bypassed; A method of medical fluid treatment comprising: (Item 32) 32. The medical fluid treatment method of claim 31, wherein the filter membrane and the bypass occur within a filter that houses the filter membrane. (Item 33) 33. The medical fluid treatment method according to claim 31 or 32, wherein the medical fluid prepared at the point of use for treatment is a peritoneal dialysis fluid. (Item 34) 1. A method of filtering a fluid, comprising: allowing fluid flowing from a first port of a filter to a second port of said filter to be filtered; allowing fluid flowing from a second port of the filter to a first port of the filter to bypass filtration; A method comprising: (Item 35) 35. The method of filtering fluid according to claim 34, wherein allowing fluid flowing from the second port of the filter to the first port of the filter to bypass filtration comprises redirecting fluid flowing from the second port of the filter to the first port away from a filtration mechanism. (Item 36) 36. The method of filtering fluid according to claim 34 or 35, further comprising allowing fluid flowing from a first port of the filter to a second port of the filter to bypass a fluid path used by fluid flowing from the second port of the filter to the first port of the filter. [Brief description of the drawings]

[0072] [Figure 1] FIG. 1 is a front elevation view of one embodiment of a medical fluid delivery system with point-of-use dialysate generation of the present disclosure.

[0073] [Diagram 2] FIG. 2 is an elevational view of one embodiment of a disposable set for use with the system illustrated in FIG.

[0074] [Diagram 3] 3 is an elevational cross-sectional view of one embodiment of a patient line filter that can be used with the disposable set of FIG. 2.

[0075] [Figure 4] FIG. 4 is a perspective cross-sectional view of one embodiment of a patient line filter that can be used with the disposable set of FIG.

[0076] [Diagram 5] FIG. 5 is a perspective cross-sectional view of one embodiment of a patient line filter that can be used with the disposable set of FIG. 2 with the filter housing removed to better show an embodiment of a filter membrane.

[0077] [Figure 6] FIG. 6 is a perspective cross-sectional view of one embodiment of a patient line filter usable with the disposable set of FIG. 2 with the filter housing and filter membranes removed to better show an embodiment of a spacer grid located between the filter membranes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0078] (System Overview) The embodiments described herein are applicable to any medical fluid therapy system that delivers medical fluids, such as dialysate, substitute fluids, or intravenous drugs, that may be mixed at the point of use prior to and / or during treatment. The embodiments are particularly well suited for renal failure therapies, such as peritoneal dialysis ("PD"), hemodialysis ("HD"), hemofiltration ("HF"), hemodiafiltration ("HDF"), and all forms of continuous renal replacement therapy ("CRRT"), collectively or generally individually referred to herein as renal failure therapies. Additionally, the machines described herein may be used in clinical or home settings. For example, the machines and associated methods may be employed in in-center PD or HD machines that run virtually continuously throughout the day. Alternatively, the machines and methods may be used in home PD or HD machines that may be run, for example, overnight while the patient is asleep. The machines and methods discussed herein are also applicable to medical delivery applications. The following examples will be described in the setting of a peritoneal dialysis system with point-of-use dialysate generation, but may alternatively be used to create point-of-use therapy fluid for any of the therapies listed above.

[0079] Referring now to the drawings, and in particular to FIG. 1 , one embodiment of a peritoneal dialysis system with point-of-use dialysate generation of the present disclosure is illustrated by system 10. System 10 includes a circulator 20 and a water purifier 210. Suitable circulators for circulator 20 include, for example, Amia® or HomeChoise® circulators sold by Baxter International Inc., with the understanding that those circulators include updated programming to implement and use the point-of-use dialysate generated according to system 10. To this end, circulator 20 includes a control unit 22 having at least one processor and at least one memory. Control unit 22 further includes a wired or wireless transceiver for transmitting information to and receiving information from water purifier 210. Water purifier 210 also includes a control unit 212 having at least one processor and at least one memory. Control unit 212 further includes a wired or wireless transceiver for transmitting information to and receiving information from control unit 22 of circulator 20. Wired communication may be, for example, via an Ethernet connection. Wireless communication may be implemented via any of the following: Bluetooth, WiFi, Zigbee, Z-Wave, wireless universal serial bus ("USB"), or infrared protocols, or via any other suitable wireless communication technology.

[0080] The circulator 20 includes a housing 24 that holds equipment that is programmed via the control unit 22 to prepare fresh dialysis solution at the point of use, pump the freshly prepared dialysate to the patient P, allow the dialysate to dwell in the patient P, and then pump the spent dialysate to a drain. In the illustrated embodiment, the water purifier 210 includes a drain line 214 that leads to a drain 216, which may be an indoor drain or a drain container. The equipment that is programmed via the control unit 22 to prepare fresh dialysis solution at the point of use may, in certain embodiments, include, but is not limited to, (i) one or more positive pressure reservoirs, (ii) one or more negative pressure reservoirs, (iii) a compressor and vacuum pump, each under the control of the control unit 22, to provide positive and negative pressures to be stored in the one or more positive and negative pressure reservoirs, or a single pump that generates both positive and negative pressures under the control of the control unit 22, (iv) a number of pneumatic valve chambers for delivering the positive and negative pressures to a number of fluid valve chambers, and (v) a number of pneumatic pumps for delivering the positive and negative pressures to a number of fluid pump chambers. The pneumatic pump system includes equipment including a pneumatic pump chamber, (vi) a plurality of electrically actuated on / off pneumatic solenoid valves under the control of the control unit 22 positioned between the plurality of pneumatic valve chambers and the plurality of fluid valve chambers, (vii) a plurality of electrically actuated variable orifice pneumatic valves under the control of the control unit 22 positioned between the plurality of pneumatic pump chambers and the plurality of fluid pump chambers, (viii) a heater under the control of the control unit 22, in one embodiment, for heating the dialysis fluid as it is mixed, and (ix) a shutoff device 26 under the control of the control unit 22 for closing the patient and drain lines in alarm and other situations.

[0081] In one embodiment, the pneumatic valve chambers and the pneumatic pump chambers are located on the front or surface of the housing 24 of the circulator 20. The heater is located inside the housing 24 and in some embodiments includes a heating coil that contacts a heating pan or tray that is located on the top of the housing 24 under a heated lid (not seen in FIG. 1 ).

[0082] The circulation device 20 in the illustrated embodiment includes a user interface 30. The control unit 22 in one embodiment includes a video controller, which may have its own processing and memory for interacting with the main control processing and memory of the control unit 22. The user interface 30 includes a video monitor 32, which may operate in conjunction with a touch screen overlay located on the video monitor 32 for inputting commands to the control unit 22 via the user interface 30. The user interface 30 may also include one or more electromechanical input devices, such as membrane switches or other buttons. The control unit 22 may further include an audio controller for playing audio files, such as voice-activated commands, on one or more speakers 34.

[0083] The water purifier 210 in the illustrated embodiment also includes a user interface 220. The control unit 212 of the water purifier 210 in an embodiment includes a video controller, which may have its own processing and memory for interacting with the main control processing and memory of the control unit 212. The user interface 220 includes a video monitor 222, which may also operate with a touch screen overlay installed on the video monitor 222 for inputting commands into the control unit 212. The user interface 220 may also include one or more electromechanical input devices, such as membrane switches or other buttons. The control unit 212 may further include an audio controller for playing audio files, such as alarms or alert sounds, on one or more speakers 224 of the water purifier 210.

[0084] Additionally, referring to FIG. 2, one embodiment of a disposable set 40 is illustrated. The disposable set 40 is also illustrated in FIG. 1 mated to the circulator 20 to move fluids within the disposable set 40, for example, to mix dialysis fluid as discussed herein. The disposable set 40 in the illustrated embodiment includes a disposable cassette 42, which may include a flat rigid plastic part covered on one or both sides by a flexible membrane. The membrane pressed against the housing 24 of the circulator 20 forms a pump and valve membrane. FIG. 2 illustrates that the disposable cassette 42 includes a fluid pump chamber 44 that operates with a pneumatic pump chamber located in the housing 24 of the circulator 20, and a fluid valve chamber 46 that operates with a pneumatic valve chamber located in the housing 24 of the circulator 20.

[0085] 1 and 2 illustrate that the disposable set 40 includes a patient line 50 that extends from a patient line port of the cassette 42 and terminates in a patient line connector 52. FIG. 1 illustrates that the patient line connector 52 connects to a patient transfer set 54, which in turn connects to an indwelling catheter located in the abdominal cavity of the patient P. The patient line 50 also includes a sterile, sterilizing grade filter 100, discussed in detail below. The disposable set 40 includes an exhaust line 56 that extends from an exhaust line port of the cassette 42 and terminates in an exhaust line connector 58. FIG. 1 illustrates that the exhaust line connector 58 removably connects to an exhaust connector 218 of the water purifier 210.

[0086] 1 and 2 further illustrate that the disposable set 40 includes a heater / mixing line 60 that extends from a heater / mixing line port of the cassette 42 and terminates in a heater / mixing bag 62, discussed in more detail below. The disposable set 40 includes an upstream water line segment 64a that extends to a water inlet 66a of a water accumulator 66. A downstream water line segment 64b extends from a water outlet 66b of the water accumulator 66 to the cassette 42. In the illustrated embodiment, the upstream water line segment 64a begins at a water line connector 68 and is located upstream from the water accumulator 66. FIG. 1 illustrates that the water line connector 68 is removably connected to a water outlet connector 228 of the water purifier 210.

[0087] The water purifier 210 outputs water, potentially water suitable for peritoneal dialysis ("WFPD"). A sterile, sterilizing grade filter 100 in the patient line 50 ensures that any contaminants in the water exiting the water purifier 210 are removed. In addition to the sterile, patient line, sterile grade filter 100, the system 10 may, but need not, provide one or more sterile, sterilizing grade filters in one or more of the water lines. In the illustrated embodiment, a sterile, sterilizing grade filter 90a is placed upstream from a downstream, sterile, sterilizing grade filter 90b, respectively. Filters 90a and 90b may be placed in the water line section 64a upstream of the water reservoir 66. The sterile, sterilizing grade filters 100, 90a, and 90b may be pass-through filters without an exclusion line. The pore size of the filtration membrane of filters 100, 90a, and 90b may be less than 1 micron, such as, for example, 0.1 or 0.2 microns. Suitable sterile, sterilizing grade filters 100, 90a, and 90b may be provided by the applicants of the present disclosure. In certain embodiments, only one of the upstream or downstream sterile filters 90a and 90b is required to generate a WFPD, nevertheless, two sterile, sterilizing grade filters 90a and 90b may be provided in the illustrated embodiment for redundancy in case one fails.

[0088] 2 further illustrates that a last bag or sample line 72 may be provided that extends from a last bag or sample port of cassette 42. The last bag or sample line 72 terminates in a connector 74 that may be connected to a mating connector of a premixed last fill bag of dialysate or to a sample bag or other sample collection container. The last bag or sample line 72 and connector 74 may alternatively be used for a third type of concentrate, if desired.

[0089] 1 and 2 illustrate that the disposable set 40 includes a first, e.g., glucose, concentrate line 76 that extends from a first concentrate port of the cassette 42 and terminates in a first, e.g., glucose, cassette concentrate connector 80a. A second, e.g., buffer, concentrate line 78 extends from a second concentrate port of the cassette 42 and terminates in a second, e.g., buffer, cassette concentrate connector 82a.

[0090] 1 illustrates that a first concentrate container 84a holds a first concentrate, e.g., glucose, that is pumped from container 84a through container line 86 to a first container concentrate connector 80b that mates with a first cassette concentrate connector 80a. A second concentrate container 84b holds a second concentrate, e.g., buffer, that is pumped from container 84b through container line 88 to a second container concentrate connector 82b that mates with a second cassette concentrate connector 82a.

[0091] In one embodiment, to begin treatment, the patient P loads the cassette 42 into the circulator and, in a random or designated order, (i) places the heater / mixing bag 62 on the circulator 20, (ii) connects the upstream water line section 64a to the water outlet connector 228 of the water purifier 210, (iii) connects the drain line 56 to the drain connector 218 of the water purifier 210, (iv) connects the first cassette concentrate connector 80a to the first container concentrate connector 80b, and (v) connects the second cassette concentrate connector 82a to the second container concentrate connector 82b. At this point, the patient connector 52 is still capped. Once the fresh dialysate is prepared and verified, the patient line 50, including the sterile, sterilizing grade filter 100, is primed with the fresh dialysate, after which the patient P may connect the patient line connector 52 to the transfer set 54 for treatment. Each of the above steps may be illustrated graphically on the video monitor 32 and / or provided via audio guidance from the speaker 34.

[0092] With respect to the disposable set 40, the rigid portion of the cassette 42 may be made of cyclic olefin copolymer ("coc"), for example, thermal olefin polymer of amorphous structure ("TOPAS"). The flexible membrane of the cassette 42 may be made of, for example, copolyetherether ("PCCE"), and may be one or more layers. Any of the tubing or lines may be made of, for example, polyvinyl chloride ("PVC"). Any of the connectors may be made of, for example, acrylonitrile butadiene styrene ("ABS", for example, for the connector 70 of the heater / mixing bag or container 62 and / or the concentrate connectors 80a, 80b, 82a, 82b discussed below), acrylic (for example, for the discharge line connector 58), or PVC (for example, for the water line connector 68). Any of the bags or containers, such as the heater / mixing bag or container 62 discussed below, may be made of PVC. The materials for any of the above components may be changed over time. The housing for the sterile, sterilizing grade filter 100 may be made from any of the materials listed above.

[0093] The control unit 22 may be programmed to cause the circulator 20 to perform one or more mixing functions to aid in mixing the dialysis fluid appropriately and homogeneously for treatment. For example, any of the fluid pump chambers 44 may be caused to draw a volume of mixed fluid (e.g., made from one or both of the first and second concentrates 84a, 84b and purified water) from the heater / mixing bag 62 into the pump chamber and return such mixture to the heater / mixing bag 62, repeating this procedure multiple times (described herein as a mixing sequence or "waffling"). In particular, to perform a mixing sequence, the control unit 22 in one embodiment causes the circulator 20 to close all fluid valve chambers 46 in the cassette 42 except for the fluid valve chambers 46 to the heater / mixing line 60 and the heater / mixing bag 62. The fluid pump chambers 44 are stroked repeatedly in succession to (i) pull a potentially unmixed fluid combination of purified water and concentrate from the heater / mixing bag 62 into the pump chamber, followed by (ii) pushing the mixed purified water and concentrate from the pump chamber back to the heater / mixing bag 62, and (iii) repeating (i) and (ii) at least once. The control unit 22 may be programmed to stroke the fluid pump chambers 44 and associated valves 46 together to both pull and push simultaneously, or alternately so that one pump chamber 44 pulls from the heater / mixing bag 62 while the other pump chamber 44 pushes to the heater / mixing bag 62, creating turbulent flow within the heater / mixing line 60.

[0094] Providing a container or bag 62 operable with cassette 42 and heater / mixing line 60 allows the purified water from the water accumulator 66 and the concentrates from the first and second concentrate containers 84a and 84b to at least partially mix before entering the container or bag. However, even if cassette 42 is not provided, the purified water and at least one concentrate will partially mix in the heater / mixing line 60 prior to reaching the container or bag. (Patient Line Filter)

[0095] 3, a schematic diagram of an embodiment of a patient-line sterile, sterilizing-grade filter 100 is illustrated showing the flow paths taken by fresh dialysate and spent dialysate returning from the patient that are mixed online at the point of use to the patient. In one embodiment, the control unit 22 of the circulator 20 causes the fluid pump chamber 44 and fluid valve chamber 46 of the disposable cassette 42 to pump fresh dialysate under positive pressure from right to left in FIG. 3 and from the cassette 42 to the patient P. The control unit 22 of the circulator 20 causes the fluid pump chamber 44 and fluid valve chamber 46 of the disposable cassette 42 to pump spent dialysate under negative fluid pressure from left to right in FIG. 3 and from the patient P to the cassette 42.

[0096] The patient line aseptic sterilizing grade filter 100 includes a filter housing 102, any one or more components of which may be made from any of the materials listed above, or may be made from one or more molded, e.g., injection molded, parts. In the illustrated embodiment, the housing 102 includes an elongated enclosure 104 that is sealed at two ends by a first port cap 106 and a second port cap 112. The first port cap 106 includes a first port 108 and defines a first manifold or open area 110, while the second port cap 112 includes a second port 114 and defines a second manifold or open area 116. The first and second ports 108 and 112 may be configured to sealingly connect to a section of the patient line 50 via a compression fitting (wherein the port has a compression connector), a hose barb fitting (wherein the port has a hose barb), a luer connection (wherein the port has a male or female luer connector), an extension of the patient line fitting (wherein the outer diameter of the port is larger than the inner diameter of the section of the patient line 50), or a combination thereof.

[0097] 3 illustrates that the filter housing 102 in one embodiment forms a spent dialysate pathway 118 and houses a fresh dialysate pathway 120. The first manifold or open area 110 and the second manifold or open area 116 can receive both fresh and spent dialysate. The line with the arrow pointing to the right indicates spent dialysate flowing through the spent dialysate pathway 118, while the line with the arrow pointing to the left indicates fresh dialysate flowing through the fresh dialysate pathway 120. The fresh dialysate pathway 120 as illustrated splits into a first upper branch 122 and a second lower branch 124. As illustrated in more detail below, the fresh dialysate flows downward from the first upper branch 122 through a plurality of generally parallel passages created by the first filter membrane and the inner grid into an interior region 126 of the fresh dialysate pathway 120. Similarly, fresh dialysate flows upwardly from the second lower branch 124 through a plurality of generally parallel passageways created by the second filter membrane and the interior grid into an interior region 126 of the fresh dialysate pathway 120.

[0098] The first port cap 106 houses a first one-way valve 150a that is sealed to the structure and forms the fresh dialysate pathway 120. The second port cap 112 houses a second one-way valve 150b that is sealed to the extension enclosure 104 of the filter housing 102 and, in the embodiment shown, forms the spent dialysate pathway 118. The first and second one-way valves 150a and 150b may be made from a medically safe rubber or plastic, such as silicone or any of the flexible materials listed above. The first and second one-way valves 150a and 150b may be, for example, duckbill check valves.

[0099] As illustrated in FIG. 3, the first one-way valve 150a is oriented to open under the positive pressure of fresh dialysate delivered by the pump cassette 42 through the fresh dialysate pathway 120. Fresh dialysate exiting the one-way valve 150a flows through the first port 108 of the first port cap 106 and a section of the patient line 50 to the patient P. However, the orientation of the one-way valve 150a is such that the valve 150a closes under the negative pressure from the pump cassette 42, drawing spent dialysate through the first port 108 of the first port cap 106 and into the filter 100. In this manner, the spent dialysate is prevented from entering the fresh dialysate pathway 120 and contacting the filter membrane, which is desirable because filtering the spent dialysate removes contaminants from the spent dialysate and may clog the filter membrane and reintroduce the contaminants into the next cycle of fresh fluid.

[0100] 3, the second one-way valve 150b is oriented to open under the negative pressure of spent dialysate drawn through the spent dialysate pathway 118 by the pump cassette 42. The spent dialysate exiting the one-way valve 150b flows through the second port 114 of the second port cap 112 and a section of the patient line 50 to the disposable cassette 42. However, the orientation of the one-way valve 150b is such that the valve 150b closes under the positive pressure from the pump cassette 42, forcing fresh dialysate through the second port 114 of the second port cap 112 and into the filter 100. In this manner, all fresh dialysate is forced to proceed through the fresh dialysate pathway 120, including its filtration membrane.

[0101] Referring now to FIG. 4, the patient line sterile sterilizing grade filter 100 is illustrated in more detail. Here, a cross section is taken through the patient line 50, the filter housing 102, the spent dialysate pathway 118, the fresh dialysate pathway 120, the first port cap 106, the second port cap 112, and the one-way valves 150a and 150b. As discussed above, the filter housing 102, in one embodiment, defines the spent dialysate pathway 118 and retains the one-way valve 150b. In FIG. 4, the second port cap 112 may also be formed with or sealed to the filter housing 102. As referred to herein, "sealed to" may mean, but is not required to mean, "glued to," "ultrasonic welded to," "solvent bonded to," "mechanically sealed to," or any combination thereof.

[0102] 4 illustrates that in one embodiment, the filter membrane and one-way valve 150a may be held by a membrane housing 130 that is located within and sealed to the filter housing 102. The membrane housing 130 may be made from any of the materials discussed herein and may be molded, e.g., injection molded, in one or more pieces and sealed to the filter housing 102 and first port cap 106 via any of the techniques described herein. In the illustrated embodiment, the first port cap 106 is sealed to the membrane housing 130. In an alternative embodiment, the port cap 106 may be formed with the membrane housing 130.

[0103] In the illustrated embodiment of Figure 4, both the filter housing 102 and the membrane housing 130 are involved in forming a fresh dialysate pathway 120. An upper branch 122 of the fresh dialysate pathway 120 is located between an upper wall 128a of the filter housing 102 and an upper wall of the membrane housing 130 (which houses an upper filter membrane as illustrated below). A lower branch 124 of the fresh dialysate pathway 120 is located between a dividing wall 128b of the filter housing 102 and a lower wall of the membrane housing 130 (which houses a lower filter membrane as illustrated below). An interior region 126 of the fresh dialysate pathway 120 is located within the membrane housing 130.

[0104] 4 illustrates in more detail the structure and orientation of the one-way valves 150a and 150b. The one-way valve 150a may be sealed, e.g., glued, to the membrane housing 130 and / or crimped between the membrane housing 130 and the first port cap 106. In the illustrated embodiment, the one-way valve 150a is a duckbill check valve with its slitted duckbill angled toward the patient P so that the positive pressure of the fresh dialysate provided by the pump cassette 42 opens the slit from inside the check valve and the negative pressure from the cassette 42 pumping the used dialysate cannot open the slit. The one-way valve 150b may be sealed, e.g., glued, to the filter housing 102 and / or crimped between the filter housing 102 and the second port cap 114 as shown. In the illustrated embodiment, one-way valve 150b is also a duckbill check valve with its slitted duckbill angled instead toward pump cassette 42 so that the negative pressure of spent dialysate provided by pump cassette 42 opens the slit from the outside of the check valve and the positive pressure from cassette 42 pumping fresh dialysate cannot open the slit.

[0105] 4 also illustrates that the filter housing extension enclosure 104 may include, e.g., be sealed to, one or more hydrophobic (allows air to pass but retains liquid) vents 152. The hydrophobic vents 152 allow air to escape from the sterile, non-sterile filter 100, e.g., during priming and prior to treatment. Removing air from the sterile, non-sterile filter 100 helps prevent air from reaching the patient P. Air removal also helps protect the hydrophilic membranes 140 and 142.

[0106] 5, the membrane housing 130 is shown in more detail with the filter housing 102 disconnected. The membrane housing 130 includes a mounting arm 132 that is sized and arranged to be sealed to the filter housing 102 and the first port cap 106 via any of the techniques discussed above. The mounting arm 132 is also sized and arranged to be sealed, e.g., glued, to the one-way valve 150a. The mounting arm 132 extends to a grid housing 134, which is shown in more detail below in connection with FIG. 6. Importantly, in FIG. 5, the grid housing 134 is illustrated as being sealed to upper and lower (first and second) filter membranes 140 and 142. The first upper membrane 140 filters fresh dialysate flowing downward through the first upper branch 122, while the second lower membrane 142 filters fresh dialysate flowing upward through the second lower branch 124.

[0107] Each of the filter membranes 140 and 142 is, in one embodiment, a hydrophilic membrane. A hydrophilic membrane generally allows liquid water to pass from one side of the membrane to the other and blocks air from such passage when properly wetted. The pore size of the filter membranes 140 and 142 can be less than 1 micron, such as, for example, 0.1 or 0.2 microns. This pore size helps to remove any remaining contaminants or impurities in the fresh dialysate, either from the purified water used to make the fresh dialysate, the concentrate used to make the fresh dialysate, and / or any part of the disposable set that carries the purified water or concentrate to the patient P.

[0108] 6, the membrane housing 130 discussed in connection with FIG. 5 is illustrated in more detail with the filter membranes 140 and 142 removed so that the interior region 126 of the fresh dialysate pathway 120 inside the membrane housing 130 can be viewed. In particular, the grid housing 134 is illustrated in more detail. The grid housing 134 may be made (e.g., injection molded) from any of the suitable materials discussed herein. In the illustrated embodiment, the grid housing 134 extends from the mounting arm 132 of the membrane housing 130. The grid housing 134 includes a number of baffles 136 that extend across the grid housing 134 and separate the filtered dialysate that has flowed through the filter membranes 140 and 142 into the multiple fluid channels 144 to form the interior region 126 of the fresh dialysate pathway 120. The baffles 136 help support the thin filter membranes 140 and 142 and space the membranes at a desired distance.

[0109] A plurality of cross braces 138 may be provided to maintain the baffles 136 in their illustrated separated, generally parallel relationship. The cross braces 138 are sized (narrowed) to allow filtered dialysate to flow along a channel 144 defined by the baffles 136, across the cross braces, and to a collection channel 146. The collection channel 146, in turn, channels the filtered dialysate through a first one-way valve 150a, whereupon the filtered dialysate exits the filter 100 into a downstream section of the patient line 50, as discussed herein.

[0110] It should be understood that various changes and modifications of the present preferred embodiment described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. Accordingly, such changes and modifications are intended to be covered by the appended claims. For example, the fluid pump chamber 44 may be an air-operated pump chamber or a section of peristaltic pump tubing. Similarly, the valve chamber 46 may be a section of tubing that is pneumatically actuated, e.g., a volcano valve, or acted upon by a pinch valve. Similarly, the pump and valve actuators may be pneumatic actuators or electromechanical actuators, e.g., a peristaltic pump actuator and a pinch valve, respectively.

Claims

1. 1. A peritoneal dialysis system comprising: a circulation device configured to pump peritoneal dialysis fluid; a disposable set configured to receive peritoneal dialysis fluid pumped by the circulator, the disposable set including: a filter having a membrane configured to filter the peritoneal dialysis fluid; and a housing having a first port and a second port, the first port opening at a first end of the housing and the second port opening at a second end of the housing; Equipped with The filter comprises: (i) fresh peritoneal dialysate flowing from the circulator toward a patient flows through the membrane via a fresh peritoneal dialysate pathway having an exit end located downstream from fresh peritoneal dialysate flow through the membrane; (ii) spent peritoneal dialysis fluid flowing from the patient through the filter to the circulator bypasses the membrane via a spent peritoneal dialysis fluid pathway that is installed in parallel with the fresh peritoneal dialysis fluid pathway. It is configured as follows: the membrane is located along the fresh peritoneal dialysis fluid pathway; the spent peritoneal dialysis fluid pathway is configured to allow spent peritoneal dialysis fluid flowing through the filter to bypass the membrane; a first end of the housing configured to form a first end of the fresh and spent peritoneal dialysate pathways, and a second end of the housing configured to form a second end of the fresh and spent peritoneal dialysate pathways; a first end of the fresh peritoneal dialysis solution pathway at a first end of the housing includes a first one-way valve, and a second end of the spent peritoneal dialysis solution pathway at a second end of the filter housing includes a second one-way valve.

2. 10. The peritoneal dialysis system of claim 1, wherein the disposable set includes a line extending from the filter to a connector configured to connect to a patient transfer set.

3. The peritoneal dialysis system of claim 1 , wherein the disposable set further comprises a disposable drain line.

4. The peritoneal dialysis system of claim 1 , wherein the filter is connected to a patient line extending from the circulator.

5. A peritoneal dialysis system as described in claim 1, wherein the first one-way valve is positioned and arranged to prevent spent peritoneal dialysis fluid returning from the patient from reaching the membrane.

6. The peritoneal dialysis system of claim 1, wherein the second one-way valve is positioned and arranged to prevent fresh peritoneal dialysis fluid from flowing through the filter via the spent peritoneal dialysis fluid pathway.

7. 2. The peritoneal dialysis system of claim 1, wherein the membrane is contained within a membrane housing located along the fresh peritoneal dialysis fluid pathway, and the filter is configured to allow fresh peritoneal dialysis fluid to flow from outside the membrane housing through the membrane into an interior region of the membrane housing.

8. 2. The peritoneal dialysis system of claim 1, wherein the membrane is housed within a membrane housing, fresh peritoneal dialysis fluid entering the filter flows to the outside of the membrane housing, and fresh filtered peritoneal dialysis fluid exiting the filter flows from the inside of the membrane housing.

9. 2. The peritoneal dialysis system of claim 1, wherein the membrane is a first membrane, the filter includes a second membrane, the first and second membranes are housed in a membrane housing, and fresh peritoneal dialysis fluid entering the filter is divided into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane.

10. 10. The peritoneal dialysis system of claim 9, wherein the membrane housing includes a grid of passageways located between the first and second membranes.

11. 10. The peritoneal dialysis system of claim 9, wherein the first and second membranes are located on opposite sides of the membrane housing, the first branch extending to a first side of the housing, and the second branch extending to a second side of the housing.

12. 10. The peritoneal dialysis system of claim 1, including at least one hydrophobic vent for removing air from the filter.

13. 1. A peritoneal dialysis system comprising: a circulation device configured to pump peritoneal dialysis fluid; A disposable set configured to receive peritoneal dialysis fluid pumped by the circulator, the disposable set including a filter through which peritoneal dialysis fluid is intended to flow in a first and second direction, the filter configured to filter peritoneal dialysis fluid flowing in the first direction and not filter peritoneal dialysis fluid flowing in the second direction, the filter comprising: a filter housing including a first port and a second port, the first port opening to a first end of the filter housing and the second port opening to a second end of the filter housing; a first fluid pathway provided by the filter housing for flowing peritoneal dialysis fluid in the first direction; a second fluid path provided by the filter housing for flowing peritoneal dialysis fluid in the second direction; and a membrane positioned to filter peritoneal dialysis fluid flowing in the first direction, the exit end of the first fluid pathway being downstream from peritoneal dialysis fluid flow through the membrane; Disposable set including Equipped with a first end of the filter housing configured to form first ends of the first and second fluid paths; a second end of the filter housing configured to form second ends of the first and second fluid paths; a first end of the first fluid pathway at a first end of the filter housing includes a first one-way valve, and a second end of the second fluid pathway at a second end of the filter housing includes a second one-way valve.

14. 14. The peritoneal dialysis system of claim 13, wherein the membrane is contained within a membrane housing located within the filter housing and along the fresh fluid pathway, and the filter is configured such that fresh peritoneal dialysis fluid flows from outside the membrane housing through the membrane into an interior region of the membrane housing.

15. 14. The peritoneal dialysis system of claim 13, wherein the membrane is housed within a membrane housing located within the filter housing, and fresh peritoneal dialysis fluid entering the filter flows to the outside of the membrane housing, and fresh filtered peritoneal dialysis fluid exiting the filter flows from the inside of the membrane housing.

16. 14. The peritoneal dialysis system of claim 13, wherein the membrane is a first membrane, the filter includes a second membrane, the first and second membranes are contained within a membrane housing located within the filter housing, and fresh peritoneal dialysis fluid entering the filter is divided into a first branch that flows to the outside of the first membrane and a second branch that flows to the outside of the second membrane.

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