Peritoneal dialysis system with disinfection gas release

Abstract

A peritoneal dialysis ("PD") system includes: a PD fluid pump; a disinfection loop, the disinfection loop comprising the PD fluid pump, the disinfection loop comprising a PD fluid, the PD fluid being used to disinfect the disinfection loop; and an acidic solution source positioned and arranged for supplying an acidic solution to the disinfection loop during disinfection with the PD fluid. The disinfection loop includes an air collector and a pressure sensor positioned and arranged for sensing PD fluid pressure during disinfection, the pressure sensor outputting to a control unit, the control unit is configured to open at least one gas valve positioned along at least one gas line leading to an upper portion of the air collector when the PD fluid pressure reaches or exceeds a threshold PD fluid pressure due to gas formation caused by mixing of an acidic solution with the PD fluid.

Description

[0001] Priority claims and cross-references to related applications

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 354,523, filed on June 22, 2022, entitled “PERITONEAL DIALYSIS SYSTEM HAVING DISINFECTION GAS RELIEF,” the entire contents of which are incorporated herein by reference in their entirety and are relied upon. Technical Field

[0003] The present disclosure relates generally to medical fluid therapy, and in particular to dialysis fluid therapy. Background Art

[0004] For various reasons, a person's kidney system may fail. Kidney failure leads to a variety of physiological disturbances. It is no longer possible to balance water and minerals or to excrete the daily metabolic load. Toxic end products of metabolism, such as urea, creatinine, uric acid, etc., may accumulate in the patient's blood and tissues.

[0005] Decreased kidney function and especially kidney failure requires treatment through dialysis. Dialysis removes waste products, toxins and excess water from the body that would otherwise be removed by the normally functioning kidneys. Dialysis treatment to replace kidney function is vital for many people because this treatment is life-saving.

[0006] One type of renal failure therapy is hemodialysis ("HD"), which typically 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 dialysate or dialysis fluid) to induce diffusion.

[0007] Hemofiltration ("HF") is an alternative renal replacement therapy that relies on the convective transport of toxins from the patient's blood. HF is achieved by adding a replacement fluid, or substitution fluid, to the extracorporeal circuit during treatment. During HF treatment, the replacement fluid, as well as the patient's accumulated fluid between treatments, is ultrafiltered, providing a convective transport mechanism that is particularly beneficial in removing intermediate and large molecules.

[0008] Hemodiafiltration ("HDF") is a treatment procedure that combines both convective and diffusive clearance. HDF uses a dialysis fluid flowing through a dialyzer, similar to standard hemodialysis, to provide diffusive clearance. In addition, a replacement solution is provided directly to the extracorporeal circuit, thereby providing convective clearance.

[0009] Most HD, HF, and HDF treatments occur at a center. Today there is a trend toward home hemodialysis ("HHD"), in part because HHD can be performed daily, providing treatment benefits over in-center hemodialysis treatments, which are typically performed every two or three weeks. Studies have shown that more frequent treatments can remove more toxins and waste products and reduce interdialytic fluid overload than patients who receive less frequent but potentially longer treatments. Patients who receive more frequent treatments do not experience as many down cycles (fluctuations in fluids and toxins) as in-center patients, who have accumulated toxins for two or three days before treatment. In some areas, the nearest dialysis center may be miles from the patient's home, resulting in door-to-door treatment time taking up a large part of the day. Treatment at a center close to the patient's home may also take up a large part of the patient's day. HHD can be performed at night or during the day while the patient is relaxing, working, or engaging in other productive activities.

[0010] Another type of renal failure therapy is peritoneal dialysis ("PD"), which infuses a dialysis solution (also called dialysis fluid) into the patient's peritoneal cavity via a catheter. The dialysis fluid contacts the peritoneum in the patient's peritoneal cavity. Waste products, toxins, and excess water pass from the patient's bloodstream through the capillaries in the peritoneum and enter the dialysis fluid due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. An osmotic agent in the PD dialysis fluid provides the osmotic gradient. Used or consumed dialysis fluid is discharged from the patient, thereby removing waste products, toxins, and excess water from the patient. This cycle is repeated, for example, multiple times.

[0011] There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis ("CAPD"), automated peritoneal dialysis ("APD"), tidal flow peritoneal dialysis, and continuous flow peritoneal dialysis ("CFPD"). CAPD is a manual dialysis treatment. Here, the patient manually connects an implanted catheter to a drain to allow used or consumed dialysis fluid to drain from the peritoneal cavity. The patient then switches the fluid connection so that the patient's catheter is connected to a fresh PD fluid bag to inject fresh PD fluid into the patient's body through the catheter. The patient disconnects the catheter from the fresh PD fluid bag and allows the dialysis fluid to reside in the peritoneal cavity, where the transfer of waste, toxins, and excess water occurs. After the residence period, the patient repeats the manual dialysis procedure, for example four times a day. Manual peritoneal dialysis requires a lot of time and effort from the patient, leaving ample room for improvement.

[0012] Automated peritoneal dialysis ("APD") is similar to CAPD in that dialysis treatment includes drain, fill, and dwell cycles. However, a PD machine typically performs these cycles automatically while the patient sleeps. A PD machine relieves the patient from having to manually perform treatment cycles and from having to deliver supplies during the day. The PD machine is fluidly connected to an implanted catheter, to a source or bag of fresh dialysis fluid, and to a fluid drain. The PD machine pumps fresh dialysis fluid from a dialysis fluid supply source through the catheter and into the patient's peritoneal cavity. The PD machine also allows the dialysis fluid to dwell within the chamber and allows the transfer of waste, toxins, and excess water to occur. The supply source may include multiple liters of dialysis fluid, which may include multiple solution bags.

[0013] The PD machine pumps the used or spent dialysate from the patient's peritoneal cavity through a catheter for draining. As with the manual process, several drain, fill, and dwell cycles occur during the dialysis process. The "final fill" may occur at the end of the PD treatment. This final fill fluid may remain in the patient's peritoneal cavity until the next treatment begins, or may be manually drained at some point during the day.

[0014] In any of the above procedures using an automatic machine, the automatic machine is typically operated using a disposable kit that is discarded after a single use. Depending on the complexity of the disposable kit, the cost of using one kit every day can become significant. In addition, daily disposables require storage space, which can become a hassle for homeowners and businesses. In addition, daily disposable changes require daily setup time and effort by the patient or caregiver at home or in the clinic.

[0015] For each of the above reasons, it is desirable to provide a PD machine that reduces disposable waste. In doing so, to the extent that calcium carbonate deposits are produced via sterilization, such deposits can be prevented by introducing an acidic solution. Product gases produced by the introduction of the acidic solution can be released into the sterilization piping of the PD machine. Therefore, there is a need for a method of releasing such gases. Summary of the invention

[0016] Known automated peritoneal dialysis ("PD") systems typically include a machine or cycler that receives and actuates a pumping cassette having a hard portion and a soft portion that is deformable for performing pumping and valving operations. The hard portion is attached to tubing that extends to various bags. The disposable cassette and associated tubing and bags can be cumbersome for patients to load at home for treatment. The total volume of disposable items can also result in multiple setup procedures that require patient input, which can create room for error.

[0017] On the other hand, the PD systems and related methods of the present disclosure convert many of the fluid-bearing portions of their PD systems into reusable parts that are sterilized after treatment. Fluid lines within the machine or circulator are reused. The remaining disposable items may include a drain line that leads to a drain bag or house drain and one or more dialysis fluid containers or bags, such as PD fluid containers for different dextrose or glucose levels and a final bag container, such as a container for icodextrin. In one embodiment, a disposable filter is placed at the distal end of the patient line to provide a final stage of filtration of the PD fluid before the PD fluid is delivered to the patient.

[0018] The PD system of the present disclosure includes a PD circulator having a housing. At least one and possibly three or more reusable PD fluid lines extend from the housing. When not connected to a PD fluid container or bag, the reusable PD fluid line can be connected to a sterile connector supported and provided by the housing. The reusable PD fluid line can, for example, extend from the front of the housing and be connected to a sterile connector also provided at the front of the housing for ready access to the PD fluid line. The reusable PD fluid line can be color coded and / or keyed to match the coloring or keyed connector of the PD fluid container or bag. The container or bag can hold dialysis fluids with different dextrose or glucose levels, such as 1.36% glucose PD fluid, 2.27% glucose PD fluid, and / or a final bag of PD fluids of different formulations (e.g., icodextrin). The PD fluid can contain a bicarbonate component.

[0019] Inside the housing, a reusable tubing system extends from each of the reusable PD fluid lines, through the PD fluid supply valve of each PD fluid line, to a PD fluid inline heater. In one embodiment, each of the valves of the PD circulator is an electrically actuated valve having a reusable valve body that blocks (e.g., when there is no power) or allows (e.g., when there is power) the flow of PD fluid through the valve body. The PD fluid inline heater is also electrically actuated in one embodiment, and is, for example, a resistive heater having a reusable heater body that receives PD fluid for heating. The inline heater is capable of heating the PD fluid from room temperature to body temperature, e.g., 37° C., at a flow rate of at least 200 milliliters (“ml”) / minute. A temperature sensor is positioned adjacent to the heater, e.g., downstream of the heater, to provide feedback for temperature control.

[0020] In one embodiment, reusable tubing extends from the outlet of the PD fluid inline heater to the air collector. Any tubing within the housing of the circulator can be metal (e.g., stainless steel), or plastic, such as polyvinyl chloride ("PVC"), or non-PVC materials, such as polyethylene ("PE"), polyurethane ("PU"), polyetheretherketone ("PEEK"), or polycarbonate ("PC"). In one embodiment, one or more liquid level sensors are positioned adjacent to the air collector so that a desired liquid level or desired liquid level range of the PD fluid is maintained in the air collector. In one embodiment, a fluid pipeline valve is positioned downstream of the air collector along the reusable fluid line. At least one gas line valve positioned along at least one gas line is provided and used as discussed herein. When commanded by the output of the liquid level sensor, the air collector can be closed upstream by the PD fluid supply valve to vent the air collector.

[0021] A reusable PD fluid pump is positioned within the circulator housing and includes a reusable pump body that receives PD fluid for pumping. That is, the pump does not require the PD fluid to flow within a disposable item, such as a tube or box. The PD fluid pump can be an electrically operated piston pump that is inherently accurate, such that a separate PD fluid volume measurement device, such as a balance chamber or a device using the ideal gas law, is not required. The PD fluid pump can alternatively be an electrically operated pump, a gear pump, or a centrifugal pump that can operate with a separate PD fluid volume measurement device.

[0022] By controlling the level of current delivered to the PD fluid pump, the PD fluid pump can be controlled to pump to and from the patient at or below a pressure limit. A positive patient pressure limit may be, for example, 1 to 5 psig (e.g., 2 psig (14 kPa)). A negative patient pressure limit may be, for example, -1.0 psig to -3.0 psig (e.g., -1.3 psig (-9 kPa)). In one embodiment, the PD fluid pump is bi-directional and continuous so that a single pump may be provided.

[0023] The PD cycler of the PD system of the present disclosure includes a control unit having one or more processors and one or more memories that receive signals or outputs from pressure sensors, temperature sensors, and possibly conductivity sensors and process the signals or outputs as feedback. The control unit uses pressure feedback to control the PD fluid pump to operate at safe patient pressure limits during treatment and at safe system limits during sterilization. The control unit uses temperature feedback to control the PD fluid heater to heat fresh PD fluid to, for example, body temperature.

[0024] The control unit also opens and closes the PD fluid valve in combination with the PD fluid pump and the heater to run a startup procedure, a patient fill procedure, a patient drain procedure, and a sterilization procedure after PD treatment, wherein each of the at least one reusable PD fluid supply lines is connected to one of the at least one sterilization connectors, and wherein the reusable patient lines are connected to the reusable patient line connectors. The sterilization procedure prepares the PD cycler for the next treatment. In one embodiment, unused fresh PD fluid is heated after final drain and used for sterilization.

[0025] Using fresh PD fluid as the disinfection fluid may result in the formation of calcium carbonate in the disinfection flow path and flow components of the PD machine or circulator if the PD fluid contains bicarbonate. Therefore, the system includes a source of an acidic solution that is used during the disinfection process to prevent the formation of calcium carbonate. The acidic solution can be, for example, a citric acid solution, such as 50% citric acid. An acidic solution valve is located between the acidic solution source and the disinfection flow path and flow components of the PD machine or circulator. In one embodiment, the control unit operates the PD fluid pump at a certain flow rate and pressure and opens the acidic solution valve for a period of time to meter the required amount of citric acid solution into the disinfection flow path and flow components of the PD machine or circulator, wherein the determined time can be empirically determined and tested. In an alternative embodiment, the PD machine or circulator includes a conductivity unit, such as a temperature compensated conductivity unit, which is used to provide feedback so that the acidic solution valve is opened until the required conductivity is reached. In another alternative embodiment, a small (eg, inherently accurate) acid solution metering pump under the control of a control unit is provided to meter the required amount of acid solution into the sterilization loop of a PD machine or cycler.

[0026] If the PD solution used for disinfection includes a bicarbonate component, the acidic solution will cause the bicarbonate to release carbon dioxide (“CO 2 ”) gas. In a closed system, the released CO 2The gas causes an increase in pressure in the sterilization loop, which may affect the reliability of certain sterilization components. In order to prevent the pressure from increasing to a point where it may affect component reliability, it is contemplated that the control unit uses the output from one or more pressure sensors to monitor the pressure within the sterilization loop during sterilization. When the pressure reaches a certain threshold above the sterilization operating pressure (e.g., 10 kPa (1.5 psig)), the control unit first checks to ensure that the sterilization fluid (e.g., PD fluid mixed with an acidic solution) is below an upper threshold or below a level sensor in the air collector of the PD machine. If so, in one embodiment, the control unit causes at least one gas or exhaust valve positioned along at least one gas or exhaust line to open. In one embodiment, the at least one gas line leads to an exhaust line connector. Thereby, the pressurized CO 2 Gas can be discharged into and out of the discharge line connector through the at least one gas line, for example, through a flexible discharge line leading from the discharge line connector to a house discharge (eg, a toilet or bathtub) or to a discharge container.

[0027] For the removal of CO 2 In an alternative embodiment of exhausting the gas, one or more PD fluid pumps are used to move the CO 2 The gas is pumped to the drain line.The PD fluid pump may be, for example, a PD fluid pump used to draw effluent from a patient and push it into a drain during treatment.

[0028] In an alternative embodiment, after the control unit confirms that the disinfecting fluid (e.g., PD fluid mixed with an acidic solution) is below an upper threshold or below a level sensor in the air collector of the PD machine, the control unit causes the valve leading to the descaling agent (e.g., citric acid) container to open so that the pressurized CO 2 Gas can flow into the container. The container may be flexible and expandable to accept CO 2 gas, or may be rigid but oversized to accept CO 2 A start-up sensor may be provided along the pipe or line leading to the descaling agent container to ensure that CO 2 Gas, rather than PD fluid, flows to this container. During the entire PD treatment, the valve is opened to allow CO 2 The flow of gas into the descaling fluid container can be performed as many times as required. 2 The gas can remain in the container until the next treatment, at which time the CO 2 Gas is pumped to the exhaust port during the start-up procedure using PD fluid.

[0029] In accordance with the disclosure set forth herein, and without limiting the disclosure in any way, in a first aspect of the disclosure (which may be used together with any other aspect or portion thereof), a peritoneal dialysis ("PD") system comprises: a PD fluid pump; a sterilization loop comprising the PD fluid pump, the sterilization loop allowing PD fluid to be used to sterilize the sterilization loop; an air collector positioned along the sterilization loop; at least one gas valve positioned along at least one gas line leading to an upper portion of the air collector; a pressure sensor positioned and arranged to sense the PD fluid pressure in the sterilization loop during a sterilization procedure; and a control unit to which the pressure sensor outputs, the control unit being configured to: cause the at least one gas valve to open when the PD fluid pressure in the sterilization loop reaches or exceeds a threshold PD fluid pressure due to gas formation caused during the sterilization procedure.

[0030] In a second aspect of the disclosure, which may be used with any other aspect or portion thereof, the gas formation is caused by mixing the PD fluid with an acidic solution.

[0031] In a third aspect of the disclosure which may be used with any other aspect or portion thereof, the control unit is configured such that before causing the at least one air valve to open, the control unit checks that the PD fluid level in the air collector is not too high.

[0032] In a fourth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PDF system comprises a drain line for draining spent PD fluid during treatment, and wherein opening the at least one gas valve allows PD fluid pressure caused by the gas formation to dissipate toward the drain line.

[0033] In a fifth aspect of the present disclosure, which may be used together with any other aspect or part thereof, the control unit is further configured to: when the PD fluid pressure reaches or exceeds the threshold PD fluid pressure, the control unit performs at least one of the following: (i) closing at least one PD fluid valve positioned adjacent to the air collector, or (ii) stopping the PD fluid pump.

[0034] In a sixth aspect of the disclosure, which may be used with any other aspect or portion thereof, the pressure sensor is positioned along one of the at least one gas line in fluid communication with the sterilization loop, thereby allowing the pressure sensor to sense PD fluid pressure during the sterilization procedure.

[0035] In a seventh aspect of the present disclosure, which may be used with any other aspect or portion thereof, after opening the at least one air valve, the pressure sensor or a second pressure sensor output to the control unit senses PD fluid pressure dissipation, and the control unit is further configured to close the at least one air valve and continue the sterilization procedure when receiving an output indicating the PD fluid pressure dissipation.

[0036] In an eighth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD fluid system is configured such that: opening of the at least one gas valve allows gas to dissipate from the upper portion of the air collector through one of the at least one gas pipelines toward an exhaust port.

[0037] In a ninth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the control unit is further configured to open the at least one gas valve or keep the at least one gas valve open for a certain amount of time based on one or more of the following data: (i) the volume of gas, (ii) the duration since the start of gas formation, and / or (iii) the number of times the control unit has previously opened the at least one gas valve.

[0038] In a tenth aspect of the disclosure, which may be used with any other aspect or portion thereof, a peritoneal dialysis ("PD") system comprises: a PD fluid pump; a disinfection loop, the disinfection loop including the PD fluid pump, the disinfection loop allowing PD fluid to be used to disinfect the disinfection loop; an acid solution source containing an acidic substance for use during a disinfection procedure; a drain line positioned and arranged to drain spent PD fluid during treatment; a gas line; and at least one gas valve positioned along the gas line, the at least one gas valve allowing communication between the gas line and the drain line. fluid connection; a pressure sensor, which is positioned and arranged to sense the PD fluid pressure in the disinfection loop during the disinfection procedure; and a control unit, to which the pressure sensor outputs, and the control unit is configured to: when the PD fluid pressure in the disinfection loop reaches or exceeds a threshold PD fluid pressure due to the formation of gas by mixing the PD fluid and the acidic substance during the disinfection procedure, the control unit causes the at least one gas valve to open, and wherein opening the at least one gas valve allows the PD fluid pressure caused by the gas formation to dissipate toward the exhaust pipeline.

[0039] In an eleventh aspect of the disclosure, which may be used with any other aspect or portion thereof, the PD system includes a heater configured to heat the PD fluid and the acidic substance to a sterilization temperature during the sterilization procedure.

[0040] In a twelfth aspect of the disclosure which may be used with any other aspect or portion thereof, the PD fluid comprises bicarbonate and the gas formed is carbon dioxide (“CO 2 ")gas.

[0041] In a thirteenth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the control unit is further configured to open the at least one gas valve, or keep the at least one gas valve open for a certain amount of time, based on one or more of the following data: (i) the volume of gas, (ii) the duration since the start of gas formation, and / or (iii) the number of times the control unit has previously opened the at least one gas valve.

[0042] In a fourteenth aspect of the present disclosure, which may be used in conjunction with any other aspect or portion thereof, a peritoneal dialysis ("PD") system comprises: a PD fluid pump; a disinfection loop including the PD fluid pump, the disinfection loop allowing PD fluid to be used to disinfect the disinfection loop; an air collector positioned along the disinfection loop; at least one gas valve positioned along at least one gas line leading to an upper portion of the air collector; a pressure sensor positioned and arranged to sense PD fluid pressure in the disinfection loop during a disinfection procedure; and a control unit to which the pressure sensor outputs, the control unit being configured to: when the PD fluid pressure in the disinfection loop reaches or exceeds a threshold PD fluid pressure due to gas formation caused during the disinfection procedure, the control unit causes the at least one gas valve to open and causes the PD fluid pump to pump a certain amount of gas from the air collector.

[0043] In a fifteenth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes a patient line valve positioned along a patient line, and wherein the control unit causes the patient line valve to open when the PD fluid pump pumps the amount of gas from the air collector.

[0044] In a sixteenth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes a discharge line valve positioned along a discharge line, and wherein, after the PD fluid pump pumps the amount of gas from the air collector, the control unit closes the patient line valve and opens the discharge line valve to deliver gas to the discharge line.

[0045] In a seventeenth aspect of the disclosure, which may be used with any other aspect or portion thereof, a peritoneal dialysis ("PD") system comprises: a PD fluid pump; a disinfection loop comprising the PD fluid pump, the disinfection loop allowing PD fluid to be used to disinfect the disinfection loop; an acid solution source containing an acidic substance for use during a disinfection procedure; a line positioned and arranged to deliver an acidic substance to the disinfection loop; at least one valve positioned along the line, the at least one valve allowing fluid communication between the line and the disinfection loop; and a pressure a force sensor, the pressure sensor being positioned and arranged to sense the PD fluid pressure in the disinfection loop during the disinfection procedure; and a control unit, the pressure sensor outputting to the control unit, the control unit being configured to: when the PD fluid pressure in the disinfection loop reaches or exceeds a threshold PD fluid pressure due to the formation of gas caused by mixing the PD fluid and the acidic substance during the disinfection procedure, the control unit causes the at least one gas valve to open, and wherein opening the at least one gas valve allows the PD fluid pressure caused by the gas formation to dissipate toward the acidic solution source.

[0046] In an eighteenth aspect of the present disclosure which may be used with any other aspect or portion thereof, the line extends from the acidic solution source to an air collector positioned along the disinfection loop.

[0047] In a nineteenth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the control unit is configured to: when the PD fluid pressure in the disinfection loop reaches or exceeds a threshold PD fluid pressure and the upper liquid level sensor in the air collector does not detect PD fluid, the control unit causes the at least one air valve to open.

[0048] In a twentieth aspect of the disclosure which may be used with any other aspect or portion thereof, the threshold PD fluid pressure is equal to or higher than an operating pressure for the sterilization procedure.

[0049] In a twenty-first aspect of the disclosure, which may be used with any other aspect or portion thereof, the PD system includes a sensor positioned along the pipeline, the sensor configured to sense between gas residing within the pipeline and the PD fluid.

[0050] In a twenty-second aspect of the present disclosure, which may be used with any other aspect or portion thereof, the control unit is configured to: when the PD fluid pressure in the disinfection loop reaches or exceeds a threshold PD fluid pressure and the output of the sensor indicates that gas resides in the pipeline, the control unit causes the at least one gas valve to open.

[0051] In a twenty-third aspect of the disclosure which may be used with any other aspect or portion thereof, the control unit is configured to: when the output of the sensor indicates that PD fluid resides in the pipeline, the control unit causes the at least one gas valve to close.

[0052] In a twenty-fourth aspect of the disclosure, which may be used with any other aspect or portion thereof, the acidic substance is citric acid, the PD fluid comprises bicarbonate, and the gas is carbon dioxide (“CO 2 ")gas.

[0053] In a twenty-fifth aspect of the disclosure, which may be used with any other aspect or portion thereof, a peritoneal dialysis ("PD") system comprises: a PD fluid pump; a disinfection loop comprising the PD fluid pump, the disinfection loop allowing PD fluid to be used to disinfect the disinfection loop; and an acidic solution source positioned and arranged to supply an acidic solution to the disinfection loop during a disinfection procedure using PD fluid.

[0054] In a twenty-sixth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes an acidic solution valve positioned between the disinfection loop and the acidic solution source, the acidic solution valve opening during a disinfection procedure to allow acidic solution to be supplied to the disinfection loop.

[0055] In a twenty-seventh aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes a control unit and a conductivity sensor output to the control unit, and wherein the control unit is configured to: during a disinfection procedure, the control unit operates the PD fluid pump and opens the acidic solution valve to allow acidic solution to be supplied to the disinfection loop until the output of the conductivity sensor indicates that a desired amount of acidic solution has been supplied.

[0056] In a twenty-eighth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes an acidic solution metering pump positioned between the disinfection loop and the acidic solution source, the acidic solution metering pump being controlled to meter a desired amount of acidic solution to the disinfection loop during a disinfection procedure.

[0057] In a twenty-ninth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the disinfection loop includes an air collector and a pressure sensor, wherein the pressure sensor is positioned and arranged to sense the PD fluid pressure during the disinfection procedure, and the pressure sensor outputs to a control unit, wherein the control unit is configured to: when the PD fluid pressure reaches or exceeds a threshold PD fluid pressure due to gas formation caused by mixing of an acidic solution with the PD fluid, the control unit opens at least one gas valve positioned along at least one gas pipeline leading to an upper portion of the air collector.

[0058] In a thirtieth aspect of the present disclosure, which may be used with any other aspect or portion thereof, the PD system includes a drain line for draining spent PD fluid during treatment, and wherein opening the at least one gas valve allows PD fluid pressure caused by gas formation due to mixing of the acidic solution with the PD fluid to dissipate toward the drain line.

[0059] In the thirty-first aspect of the present disclosure, which may be used with any other aspect or portion thereof, the control unit is further configured to: when the PD fluid pressure reaches or exceeds the threshold PD fluid pressure, the control unit performs at least one of the following: (i) closing at least one PD fluid valve positioned adjacent to the air collector, or (ii) stopping the PD fluid pump.

[0060] In a thirty-second aspect of the present disclosure, which may be used with any other aspect or portion thereof, the pressure sensor is positioned along one of the at least one gas line in fluid communication with the sterilization loop, thereby allowing the pressure sensor to sense PD fluid pressure during the sterilization procedure.

[0061] In a thirty-third aspect of the disclosure, which may be used with any other aspect or portion thereof, the PD fluid used to sterilize the sterilization loop is fresh PD fluid, and wherein the sterilization loop comprises at least one reusable PD fluid supply line previously connected to a source of fresh PD fluid.

[0062] In a thirty-fourth aspect of the disclosure, which may be used with any other aspect or portion thereof, the disinfection loop comprises at least one of (i) a reusable patient line or (ii) an inline heater, and wherein the PD fluid used to disinfect the disinfection loop is heated by the inline heater.

[0063] In a thirty-fifth aspect of the present disclosure, which may be used with any other aspect or portion thereof, in combination Figures 1 to 7 Any one or more of the features, functions and alternatives described in any one or more of the above may be combined with Figures 1 to 7 Any features, functions and alternatives described in any other figures may be combined.

[0064]

[0011] It is therefore an advantage of the present disclosure to provide a system for an automated peritoneal dialysis ("PD") cycler that helps ensure that over-pressurization does not occur during the sterilization process.

[0065] Another advantage of the present disclosure is that a system is provided for a PD cycler that helps ensure that over-pressurization does not occur during the sterilization process without requiring a vent to atmosphere that could cause sterility issues over time.

[0066] Another advantage of the present disclosure is to provide a system for a PD cycler that helps prevent sediment accumulation during the sterilization process.

[0067] Additional features and advantages are described in, and will become apparent from, the following detailed description and accompanying drawings. The features and advantages described herein are not all-inclusive, and in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the accompanying drawings and description. Furthermore, it is not necessary for any particular embodiment to have all of the advantages listed herein, and it is expressly contemplated that each advantageous embodiment is separately claimed. Furthermore, it should be noted that the language used in the specification has been selected primarily for readability and didactic purposes and not for the purpose of limiting the scope of the inventive subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 is a schematic diagram of one embodiment of an automated peritoneal dialysis ("PD") system and associated sterilization product gas removal method of the present disclosure.

[0069] Figure 2 yes Figure 1 Schematic diagram showing an example sterilization flow path or sterilization loop for the PD system of the present disclosure.

[0070] Figure 3 yes Figure 1 Schematic diagram showing an example release pressure flow path for the PD system of the present disclosure.

[0071] Figure 4 is a schematic diagram of another embodiment of an automated peritoneal dialysis ("PD") system and associated sterilization product gas removal method of the present disclosure, illustrating one preferred location of an acidic solution source.

[0072] Figure 5 is a time-varying graph showing the Figures 1 to 4 A method of PD system and an example of pressure relief using the system.

[0073] Figure 6 is a schematic diagram of an alternative embodiment of an automated peritoneal dialysis ("PD") system and associated sterilization product gas removal method of the present disclosure.

[0074] Figure 7 is a time-varying graph showing the Figure 6 A method of PD system and an example of pressure relief using the system. DETAILED DESCRIPTION

[0075] System Overview

[0076] Reference is now made to the drawings, and in particular to the Figure 1 , the automated peritoneal dialysis ("PD") system 10a and associated methods of the present disclosure include a PD machine or cycler 20. The system 10a and cycler 20 attempt to eliminate as many disposable items as possible and instead provide most of its fluid-bearing portions as reusable components that are sterilized after treatment. The fluid lines within the machine or cycler are reused. In particular, Figure 1 Circulator 20 is shown to include a housing 22 from which reusable PD fluid supply lines 24a - 24d extend. Figure 1 A reusable patient line 26 is further shown also extending from the housing 22 of the machine or cycler 20. When the reusable patient line 26 is not connected to a patient for treatment, the reusable patient line 26 (which is typically longer than the reusable PD fluid supply lines 24a-24d) can be coiled or rolled up within the housing via a reel or hose reel 28.

[0077] When not connected to a PD fluid container or bag, the reusable PD fluid supply lines 24a to 24d and the reusable patient line 26 can be connected to dedicated connectors supported and provided by the housing. The reusable PD fluid supply lines and patient lines can, for example, extend from the front of the housing and connect to connectors also provided at the front of the housing for ready access to the PD fluid lines and patient lines. In the illustrated embodiment, the distal ends 24e of the reusable PD fluid supply lines 24a to 24d are releasably attached in a fluid-tight manner to sterile connectors 30a to 30d provided at the housing 22, respectively. The distal end 26d of the reusable patient line 26 is releasably attached in a fluid-tight manner to a patient line connector 32 provided at the housing 22 (or alternatively, to a sterile cap). Sterile connectors 30a-d and patient line connector 32 may be configured to automatically close or disconnect when reusable PD fluid supply lines 24a-d and reusable patient line 26, respectively, are removed or not connected to the connectors.

[0078] Figure 1 The housing 22 is also shown to provide a drain line connector 34 that can be releasably covered by a removable (e.g., rotatable or slidable) cover. The drain line connector 34 receives a disposable drain line 36 for treatment that can extend to a drain container or bag or to a house drain. The disposable drain line 36 is connected to the drain line connector 34 during sterilization, as discussed below.

[0079] Disposable PD fluid or solution containers or bags (not shown because the system 10a is in a sterile configuration in which the containers or bags have been removed) are connected to reusable PD fluid supply lines 24a to 24d, respectively. The distal ends 24e of the reusable PD fluid supply lines 24a to 24d can be color coded and / or keyed to match the colored or keyed connectors of the dedicated PD fluid containers or bags. The containers or bags can hold PD fluids of the same or different dextrose or glucose levels, such as 1.36% dextrose PD fluid, 2.27% dextrose PD fluid, 3.86% dextrose PD fluid, PD fluid containing bicarbonate, and / or final bags of different formulations of PD fluid, such as icodextrin.

[0080] It should be understood that any number of reusable PD fluid supply lines 24a-24d and PD fluid containers or bags may be provided, including a single reusable PD fluid line and PD fluid container, or more than one reusable PD fluid line and PD fluid container. In another alternative embodiment, the PD fluid container or bag is replaced by an online PD fluid generation source that is connected to and in fluid communication with a single reusable PD fluid supply line.

[0081] In addition to the disposable drain line 36 (and associated container, if used) and the disposable PD fluid container or bag, it is contemplated that in one embodiment, the only other disposable component of the system 10a is a disposable filter kit (not shown) that is removably connected by the patient at the distal end 26d of the reusable patient line 26 to provide a final stage of PD fluid filtration prior to delivery to the patient. In one embodiment, the disposable filter kit is spliced ​​between the distal end 26d of the reusable patient line 26 and the patient's delivery kit, which in turn leads to an indwelling PD catheter inserted into the patient.

[0082] It is contemplated that any one, multiple or all of the reusable PD fluid supply lines 24a to 24d, reusable patient line 26, sterile connectors 30a to 30d, patient line connector 32, drain line connector 34, drain line 36, PD fluid containers or bags, and patient line filter kit are made of any one or more plastics, such as polyvinyl chloride ("PVC") or non-PVC materials such as polyethylene ("PE"), polyurethane ("PU"), polypropylene ("PP"), polyetheretherketone ("PEEK"), polycarbonate ("PC"), or silicone.

[0083] Figure 1As further shown, a reusable supply tube 52a extends from each reusable PD fluid supply line 24a-24d through a PD fluid supply valve 54a-54d, respectively, to a PD fluid inline heater 56. In one embodiment, each of the valves of the PD cycler 20 (including the PD fluid supply valves 54a-54d) is an electrically actuated valve having a reusable valve body that can block (e.g., when not energized for fail-safe operation) or allow (e.g., when energized) PD fluid to flow through the valve body. In the illustrated embodiment, valve 54d is a three-way valve having a normally open port for receiving PD fluid from the reusable PD fluid supply line 24b or 24c, and a normally closed port for receiving PD fluid from the reusable PD fluid supply line 24d. In one embodiment, the PD fluid inline heater 56 is also electrically actuated, and is, for example, a resistive heater having a reusable heater body that receives PD fluid for therapeutic and sterilizing heating. In one embodiment, the inline heater 56 is capable of heating the PD fluid from room temperature or lower (eg, if the PD fluid is stored in a cold environment) to body temperature, eg, 37°C, at a flow rate of up to at least 200 milliliters ("ml") / minute.

[0084] A first temperature sensor 58a is positioned adjacent to the heater 56, e.g., downstream of the heater, to provide feedback for temperature control. If desired, a second temperature sensor (not shown) may be provided upstream of the heater 56 to allow the heating algorithm to take into account the incoming temperature of the fresh PD fluid. A second temperature sensor 58b is shown just downstream of the PD fluid pump 70, which is provided, e.g., as a second check that the fresh PD fluid leaving the PD fluid pump 70 is at a desired treatment temperature (e.g., body temperature or 37°C).

[0085] In the illustrated embodiment, the flow switch 68 is positioned just upstream of the PD fluid inline heater 56. The output of the flow switch 68 is used to ensure fresh PD fluid flow through the inline heater 56. If the output of the flow switch 68 (or the absence of an output) indicates that there is no or little fresh PD fluid flow, which may be harmful to the inline heater 56 when it is powered on, it will cause the system 10a to stop powering the inline heater 56 and stop treatment or sterilization if necessary, while (i) trying to find a remedy to resolve the no flow or low flow condition, or (ii) generating an audible, visual or audio-visual alarm or alert at the user interface 108. It should be noted that the circulator 20 of the system 10a can employ additional or alternative hardware and / or software for ensuring that PD fluid is flowing when the heater 56 is powered on.

[0086] exist Figure 1In the illustrated embodiment, reusable tubing 52b extends from the outlet of the PD fluid inline heater 56 to the air collector 60. Any of the reusable tubing within the housing of the circulator 20 (including reusable tubing 52a and 52b) can be made of metal (e.g., stainless steel), or plastic, such as polyvinyl chloride ("PVC") or non-PVC materials such as polyethylene ("PE"), polyurethane ("PU"), polypropylene ("PP"), polyetheretherketone ("PEEK"), polycarbonate ("PC"), or silicone. In one embodiment, one or more level sensors 62a and 62b are positioned near the air collector 60 to maintain a desired level or level range of PD fluid in the air collector. In the illustrated embodiment, a fluid line valve 54e is positioned downstream of the air collector 60 and receives fresh, heated PD fluid from the air collector 60. A gas line valve 54g is positioned along the gas line 52g extending from the top of the air collector 60. When indicated by the output of level sensor 62a or 62b, air trap 60 may be closed upstream by PD fluid supply valves 54a to 54d to vent the air trap.

[0087] Reusable fluid line 52c and gas line 52g extend between fluid line valve 54e and gas line valve 54g, respectively, and PD fluid pump 70 located within housing 22 of circulator 20. PD fluid pump 70 includes a reusable pump body that accepts PD fluid for pumping. That is, pump 70 does not require PD fluid to flow within a disposable item (such as a tube or box). The reusable pump body of pump 70 itself accepts PD fluid. PD fluid pump 70 can be an inherently accurate type, such as a piston pump, so no separate PD fluid volume measurement device, such as a balance chamber or flow meter, is required. PD fluid pump 70 can alternatively be a less accurate gear pump or centrifugal pump that does operate with a PD fluid volume measurement device. By controlling the level of current to the PD fluid pump, PD fluid pump 70 can be controlled to pump to and from the patient at or below a pressure limit. The positive patient pressure limit can be, for example, 1 to 5 psig (e.g., 2 psig (14 kPa)). The negative patient pressure limit may be, for example, -1.0 psig to -3.0 psig (e.g., -1.3 psig (-9 kPa)). PD fluid pump 70 may also provide lower pressures if desired, such as for use with young children or infants. In one embodiment, PD fluid pump 70 is bidirectional and continuous so that a single pump may be provided.

[0088] Figure 1As further shown, in one embodiment, a fresh PD fluid patient line valve 54f is positioned along the reusable fresh PD fluid patient tubing or line 52f between the downstream temperature sensor 58b and the reel or hose drum 28. In one embodiment, the fresh PD fluid patient tubing or line 52f is in fluid communication with the fresh PD fluid lumen of the double lumen reusable patient line 26. In one embodiment, a used PD fluid patient line valve 54u is positioned along the reusable used PD fluid patient tubing or line 52u between the PD fluid pump 70 (via the spool 64a) and the reel or hose drum 28. In one embodiment, the used PD fluid patient tubing or line 52u is in fluid communication with the used PD fluid lumen of the double lumen reusable patient line 26. A drain line valve 54h is positioned along the reusable drain tubing or line 52h that extends from the tee 66 to the drain line connector 34.

[0089] A first patient pressure sensor 72a is positioned along fresh PD fluid patient tubing or line 52f between the PD fluid pump 70 and the reel or hose drum 28 to measure positive patient PD fluid pressure. A second patient pressure sensor 72b is positioned along gas line 52g to measure negative patient PD fluid pressure during patient discharge (note that gas line 52g may contain gas, PD fluid, or a combination thereof, and that any gas is at the same negative pressure as the spent PD fluid via fluid communication at spool 64a). A third pressure sensor 72c and a fourth pressure sensor 72d are positioned along reusable sterile tubing or line 52d.

[0090] As described above, the patient line connector 32 is positioned at the housing 22 of the PD cycler and receives the double lumen reusable patient line 26 during sterilization and generally when the patient is not receiving treatment. In one embodiment, the patient line connector 32 includes a sealed fluid U-turn or 180-degree turn that allows sterilization fluid (e.g., heated PD fluid) to flow from one lumen of the double lumen patient line to the other lumen of the double lumen patient line. Thus, the double lumen reusable patient line 26 is included in the sterilization loop. In an alternative embodiment, the patient line connector 32 can be replaced by a sterilization cap that includes a sealed fluid U-turn or 180-degree turn that allows sterilization fluid (e.g., heated PD fluid) to flow from one lumen of the double lumen patient line to the other lumen of the double lumen patient line. The sterilization cap can be tied to the end of the reusable patient line 26 so that it is easy to position it when needed.

[0091] As discussed further above, in one embodiment, the drain line 36 is flexible and disposable, and is connected to a drain line connector 34 extending from the housing 22 of the PD cycler 20 during treatment. In one embodiment, after treatment, the drain line 36 is left in place so that waste gases generated during the sterilization procedure can be exhausted into the drain line 36 and exhausted to a drain port of a house or container. The drain line connector 34 receives an internal reusable drain tube or line 52h for (i) conveying spent PD fluid to the drain line 36 during patient draining, and (ii) conveying air to the drain line 36 during priming. The drain line connector 34 also receives an exhaust tube or line 52v for conveying gases (such as carbon dioxide (“CO 2 ”) to the drain line 36 during sterilization. 2 ” (“gas”) is delivered to exhaust line 36 as described in detail herein. Exhaust valve 54v is positioned along exhaust pipe or line 52v.

[0092] like Figure 1 As shown in FIG. 1 , reusable sterile tubing or line 52d extends to second cross-piece 64b along with exhaust tubing or line 52v and spent PD fluid patient tubing or line 52u. Reusable sterile tubing or line 52d includes sterile valve 54s. As discussed in more detail herein, sterile tubing or line 52d handles sterile fluid or fresh, heated PD fluid, and exhaust tubing or line 52v handles exhaust gases or CO. 2 , while the used PD fluid patient tube or line 52u handles the used PD fluid during treatment and is separated during disinfection, wherein (i) the portion of the used PD fluid patient tube or line 52u between the first spool 64a and the second spool 64b is CO 2 gas to exhaust tube or line 52v, and (ii) the portion of used PD fluid patient tube or line 52u between second cross-piece 64b and reel or hose drum 28 delivers sterile fluid or fresh PD fluid to or from sterile tube or line 52d.

[0093] Figure 1Also shown is an acidic solution source 80 connected to the acidic solution connector 82. The acidic solution line 52i extends from the solution connector 82 to the three-way acidic solution valve 54i, for example, to the normally open port of the valve 54i. The three-way valve 54i also controls a bypass line 52y located between the disinfection connectors 30c and 30d, which bypass line 52y is used during the disinfection process. A similar bypass line 52z is provided between the disinfection connectors 30a and 30b. The acidic solution source 80 contains an acidic solution for use in the disinfection process as described herein. The acidic solution can be, for example, a citric acid solution, such as 50% citric acid. It should be understood that the acidic solution source 80 can be positioned almost anywhere along the disinfection loop, for example, at the bypass line 52z or along the disinfection pipe or line 52d, etc. The following discussion Figure 4 System 10b shows one preferred location for the acidic solution source 80.

[0094] Figure 1 As further shown, the PD cycler 20 of the system 10a of the present disclosure includes a control unit 100 having one or more processors 102 and one or more memories 104 for receiving, storing and processing signals or outputs from the pressure sensors 72a to 72d, the temperature sensors 58a and 58b, the flow switch 68, and possibly a conductivity sensor (not shown). The control unit 100 uses pressure feedback from the pressure sensors 72a and 72b to control the PD fluid pump 70 to pump fresh PD and used PD at safe patient limits and system pressure limits. The control unit 100 uses temperature feedback from the temperature sensor 58a to control the inline PD fluid heater 56 to heat the fresh PD fluid to, for example, body temperature or 37°C. The control unit 100 uses flow switch feedback from the flow switch 68 to determine whether to power the PD fluid inline heater 56.

[0095] The control unit 100 also opens and closes the PD fluid valves 54a to 54i, 54s, 54u, and 54v in conjunction with the operation of the PD fluid pump 70 and the heater 56 to run a startup procedure, a multiple patient fill procedure, a multiple patient drain procedure, and a sterilization procedure after PD treatment. In the sterilization procedure, each reusable PD fluid supply line 24a to 24d is connected to a corresponding sterilization connector 30a to 30d, respectively, and the reusable patient line 26 is connected to the reusable patient line connector 32. The sterilization procedure prepares the PD cycler 20 for the next treatment. In one embodiment, the remaining fresh PD fluid is heated after the final patient drain and used as a sterilization fluid for sterilization.

[0096] like Figure 1As shown in FIG. 1 , the control unit 100 may also include a video controller 106 that interfaces with a user interface 108, which may include a display screen operated by a touch screen and / or one or more electromechanical buttons (e.g., membrane switches). The user interface 108 may also include one or more speakers for outputting alarms, warnings, and / or voice guidance commands. The user interface 108 may be provided with the circulator 20 (e.g., Figure 1 ), and / or may be a remote user interface operated by the control unit 100. The control unit 100 may also include a transceiver (not shown) and a wired or wireless connection to a network (e.g., the Internet) for sending treatment data to a doctor or clinician server connected to a doctor or clinician's computer and receiving prescription instructions from the doctor or clinician server.

[0097] Reference now Figure 2 , highlighting the sterilization loop 90 including sterilization lines and components. Figure 1 All other lines and components described in Figure 2 64b. The sterile loop 90 includes (dotted line, generally introduced counterclockwise) the patient line connector 32 (including its U-turn or 180 degree turn), the two lumens of the reusable double lumen patient line 26, the portion of the used PD fluid patient tubing or line 52u between the reel or hose drum 28 and the second cross-piece 64b, the reusable sterile tubing or line 52d, the reusable PD fluid supply lines 24a to 24d, the bypass lines 52y, 52z, and the reusable tubing or lines 52a to 52c and 52f. The sterile loop 90 also includes the interior of all flow components and sensors located along the lines listed above.

[0098] During the sterilization process, the control unit 100 can cause certain of the valves along the sterilization loop 90 to operate in sequence. For example, during the sterilization process, the PD fluid supply valve 54a can be opened and closed in sequence to allow sterilization fluid to flow through the supply valve 54a or be actuated completely through the reusable PD fluid supply line 24a. The control unit 100 can also cause the PD fluid pump 70 to operate in a forward state and a reverse state in sequence during sterilization so that the sterilization fluid can flow through the sterilization loop 90 in a clockwise direction and a counterclockwise direction. The control unit 100 also causes the inline heater 56 to heat the sterilization fluid (e.g., fresh PD fluid) to a desired sterilization temperature, such as 70°C to 90°C.

[0099] Transport sterilization product gas to the exhaust port

[0100] If fresh PD fluid contains bicarbonate, using it as a disinfection fluid may result in the formation of calcium carbonate in the disinfection flow path and flow components of the disinfection loop 90 of the PD machine or circulator 20. During the disinfection process, an acidic substance from the acid solution source 80 is provided accordingly to prevent the formation of calcium carbonate. In one embodiment, the control unit 100 operates the PD fluid pump 70 at a certain flow rate and pressure, and opens the acid solution valve 54i for a certain amount of time to meter the required amount of citric acid (or other) acid solution into the disinfection flow path and flow components of the disinfection loop 90, wherein the determined time can be determined and tested empirically. In an alternative embodiment, the PD machine or circulator 20 includes a conductivity cell, such as a temperature compensated conductivity cell (not shown, but can be located anywhere along the disinfection loop, such as along the reusable disinfection tube or line 52d), which is used to provide feedback to the control unit 100 so that the acid solution valve 54i is opened until the desired conductivity is achieved in the disinfection loop 90. In another alternative embodiment, a small, eg inherently accurate, acid solution metering pump (not shown) controlled by the control unit 100 is provided for metering the required amount of acidic (eg citric acid) solution into the disinfection loop 90 .

[0101] If the heated PD solution used for disinfection includes a bicarbonate component, the acidic solution will cause the bicarbonate to convert CO 2 The gas is released into the sterilization loop 90. In the closed sterilization loop 90, the released CO 2 The gas causes an increase in pressure in the sterilization loop, which may promote internal leaks and affect the reliability of certain sterilization components located along the loop, such as the PD fluid pump 70.

[0102] exist Figure 2 In order to prevent the gas or CO 2In order to prevent the pressure increase caused by the formation of a sterilization fluid to a point that may affect the reliability of the components, the control unit 100 of the system 10a is expected to monitor the pressure inside the sterilization loop 90 during the sterilization process using the output of one or more pressure sensors (such as any one or more of the pressure sensors 72a to 72d) (pressure sensor 72b senses the sterilization pressure via fluid communication with the first spool 64a). When the pressure reaches a certain threshold above the typical sterilization operating pressure, which can be, for example, 10 kPa (1.5 psig), in one embodiment, the control unit 100 first checks to ensure that the sterilization fluid (e.g., heated fresh PD fluid mixed with an acid solution) is below an upper threshold in the air collector 60 of the PD machine or circulator 20. Here, the control unit 100 can check to ensure that the sterilization fluid has not reached the upper level sensor 62a. The control unit 100 performs this check to prevent the PD fluid from entering the gas pipeline 52g. An example threshold pressure above, for example, the 10 kPa (1.5 psig) operating pressure can be 20 kPa (2.9 psig). That is, in one example, the control unit 100 looks for an overpressure (eg, the overpressure measured at the pressure sensor 72 b ) to reach 20 kPa (2.9 psig), which is approximately twice as great as the specified operating pressure.

[0103] When overpressure is determined and the fluid level in the air collector 60 is not too high, the control unit 100 causes the sterilization valve 54e and any open valves 54a to 54d upstream of the air collector 60 to close to fluidically isolate the air collector. The control unit 100 also causes the PD fluid pump 70 to stop pumping sterilization fluid. Figure 3 As shown, the control unit 100 further causes (i) the gas line valve 54g, (ii) the spent PD fluid patient line valve 54u, and (iii) the exhaust valve 54v to open to allow the pressurized CO 2 The gas is decompressed and flows from the top of the air collector 60 along the Figure 3 The line marked by the arrow in FIG. 1 flows to the discharge line 36 via the discharge line connector 34. In the embodiment shown, the discharge line for CO 2 The path for gas decompression includes gas line 52g, the portion of the PD fluid patient tube or line 52u between crosspieces 64a and 64b, exhaust tube or line 52v, and drain line 36.

[0104] Once CO 2Once the gas has been appropriately depressurized, e.g., to atmospheric pressure or zero kPa, or possibly to a typical sterilization operating pressure, e.g., 10 kPa (1.5 psig), as sensed at the pressure sensor 72b output to the control unit 100, the control unit causes (i) the gas line valve 54g, (ii) the spent PD fluid patient line valve 54u, and (iii) the exhaust valve 54v to close, and causes the sterilization fluid valve 54e and any desired one or more upstream valves 54a to 54d to open, and actuates the PD fluid pump 70 and the inline heater 56 to continue sterilization. The depressurization procedure just described is repeated as needed prior to sterilization of the sterilization loop 90 (e.g., while the sterilization fluid (e.g., PD fluid) is being heated for sterilization) and possibly during sterilization of the sterilization loop 90. In one example, while the sterilization fluid is being heated for sterilization, the flexible drain line 36 is left in place, wherein the depressurization procedure occurs one or more times, with the drain line 36 in place to receive the removed CO 2 When the sterilization fluid is heated to the sterilization temperature, the user interface 108 audibly, visually, or audiovisually prompts the patient or user to then remove the drain line 36 from the drain line connector 34, which is then capped via the drain line cap 34c to close the sterilization loop 90 on the fluid for the sterilization procedure.

[0105] The above is used to convert CO 2 The depressurization process of the gas discharged to the discharge line 36 is described as being via the CO 2 The overpressure caused by the formation of gas is triggered. It is also noted that the decompression procedure can be performed once or multiple times. In various embodiments, (i) the triggering of the decompression procedure and (ii) the appropriate dissipation of CO 2 The total amount of time required for the gas pressure to be maintained may be a function of, and dependent upon, any one or more of the following parameters: (a) the sensed pressure in the sterilization loop 90, (b) the amount of time required for the gas pressure to be maintained, and (c) the amount of time required for the gas pressure to be maintained. 2 the start of gas production or the amount of time that has elapsed since the end of the previous depressurization procedure, (c) the CO to be dissipated 2 the volume of gas (eg, calculated by the control unit 100 knowing the citric (or other) acid concentration and the temperature of the sterilizing fluid), and / or (d) the number of previous decompression procedures that have occurred.

[0106] It should be understood that the above decompression procedure does not require a separate release valve or hydrophobic vent (although such valves and / or vents may be used if desired), which may present sterility issues. Any pathogens in the above decompression procedure are forced to move all the way up the flexible drain line 36 and are isolated during the sterilization process by the closed exhaust valve 54v and the closed drain line valve 54h.

[0107] In an alternative depressurization procedure that similarly does not require a separate relief valve or trap vent, the control unit 100 of the PD machine or circulator 20 instead causes one or more PD fluid pumps (e.g., PD fluid pump 70) to deliver sterilizing gas or CO to the PD machine or circulator 20. 2 Here, the control unit 100 can close the sterilizing fluid valve 54e and open the gas pipeline valve 54g so that the PD fluid pump 70 can draw the sterilizing gas or CO from the top of the air collector 60. 2 In order to extract the sterilizing gas or CO from the top of the air collector 60 2 , the control unit 100, with the patient line valve 54f opened and the exhaust line valve 54h closed, can cause the PD fluid pump 70 to draw a certain volume of sterilizing gas or carbon dioxide from the air collector 50, the volume being equal to the internal tubular volume along the gas line 52g between the top of the air collector 60 and the tee 66, and then close the PD fluid patient line valve 54f and open the exhaust line valve 54h to allow the PD fluid pump 70 to remove the removed volume of sterilizing gas or CO 2 Gas is pumped to the exhaust port. Any one or more of the triggering and / or timing factors (a) to (d) described above may also be used in any sterilization procedure involving the use of the PD fluid pump 70 .

[0108] Figure 4 shows a method for removing sterilizing gas or CO 2 An alternative PD system 10b is provided in which the gas is exhausted. PD system 10b includes many of the same components as PD system 10a, including disinfection loop 90, which are numbered the same and include all of the structure, functionality, and alternatives to those components described above. Figure 4 A major difference is that the acidic solution source 80 is disposed in a preferred position downstream of the PD fluid pump 70 along the fresh PD fluid portion of the disinfection loop 90. In one embodiment, the PD fluid pump 70 is used to pump CO 2 The gas is pumped to a removable exhaust line 36. Use of a PD fluid pump 70 helps minimize flushing of CO 2 The amount of PD fluid required for the gas. Figure 4 As shown, the acid solution source 80 is positioned downstream of the PD fluid pump 70 so that CO cannot be pumped to the patient during treatment. 2Gas (where PD fluid pump 70 is pumping in the forward delivery direction). In addition, two valves 54j (two-way valve) and 54k (three-way valve) are positioned between the acid solution source 80 and the fresh patient tubing or line 52f to provide redundancy in (i) preventing acidic substances from being delivered to the patient and (ii) preventing PD fluid from being pumped into the acid solution source 80 and diluting the acidic solution. System 10b also includes an additional recirculation line 52t having a recirculation valve 54t under the control of control unit 100.

[0109] In addition, using Figure 4 The system 10b improves the dose or amount of acidic material (e.g., citric acid) delivered at the beginning of a sterilization procedure. Here, before the system 10b introduces the dose of acidic material, the system adjusts the pressure at the acidic solution source 80 to atmospheric pressure, or to the last known pressure recorded at the acidic solution source 80. In order to use this last known pressure, during the metered delivery of the acidic material, the PD fluid pump 70 is reversed by a set stroke amount corresponding to the dose / stroke volume to draw the prescribed dose of acidic material into the sterilization loop 90. At the end of the metered delivery of the acidic material, the control unit 100 records the pressure measured at the pressure sensor 72a. This pressure is then stored as the start of the metered delivery pressure at the acidic solution source 80, which is used in the next sterilization procedure to improve the accuracy of the acidic material dosage. This pressure control can be applied to any embodiment of any system 10a to 10c described herein.

[0110] Figure 5 1 shows an example output of the depressurization procedure described above. The top line (dashed line) is the baseline and shows the output of the exhaust CO when a bicarbonate PD fluid is used and the depressurization procedure of system 10a is not performed. 2 The Δ-lines and x-lines are examples of PD fluids containing bicarbonate (e.g., Physioneal ® PD fluids), which have been mixed with an acidic solution (e.g., citric acid), resulting in the production of CO 2 Here, when the pressure reaches or exceeds the threshold pressure, the pressurized CO 2 The gas is released in the manner described above. Figure 5 In the tests conducted, the threshold pressure was taken as 10 kPa (1.5 psig). However, during the sterilization process of the system 10, 10 kPa (1.5 psig) may be within the operating pressure range, and the threshold pressure for triggering pressure release may be much higher. Figure 5 As shown, due to the decompression of the Δ-line and the x-line relative to the non-decompression dashed line, the exhaust gas CO 2 The resulting pressure increase is strongly suppressed.

[0111] The unlabeled lines are for a particular PD fluid sold by the assignee of the present disclosure, namely Dianeal ® PD fluid, which does not contain bicarbonate, and therefore does not require the injection of a descaling fluid, such as citric acid, during the sterilization process. Therefore, the unlabeled non-bicarbonate line can serve as a model line for the delta-line and the x-line. The difference between the bicarbonate delta-line and the x-line is that in the case of the x-line, at time t0 or the beginning of the x-line test, the patient removes the disposable drain line 36 and replaces the drain line cap 34c ( Figures 1 to 3 ) caps the discharge line connector 34. In the case of the Δ-line, the patient instead waits for a specified period of time before Figure 5 In the example shown, the wait time is 480 seconds to remove the disposable drain line 36 and to close the drain line cap 34c ( Figures 1 to 3 ) caps the drain line connector 34. During the waiting period or while the sterilization program is running, the sterilization solution is heated to the sterilization temperature, thereby generating byproduct sterilization or CO 2 In the case of the delta-line, CO is discharged only if the disposable discharge line 36 exists, for example within 480 seconds. 2 After removing the disposable exhaust line 36, no additional CO 2 The gas is vented from the system. However, the venting period as shown is long enough to make the delta-line pressure well below the dashed line baseline pressure. The x-line is a reference line in which the disposable vent line 36 is left in place throughout the test so that the CO 2 Gas was allowed to vent throughout the test. As shown, both the delta-line and the x-line generally follow the non-bicarbonate line and have pressures much lower than the dashed line baseline pressure, which shows the pressure that exists when bicarbonate PD fluid is used and the depressurization procedure of system 10a is not performed. In addition, the delta-line pressure does not increase significantly over the x-line pressure.

[0112] Transport sterilization product gas to the acid solution source

[0113] Figure 6Another alternative PD system 10c is illustrated. PD system 10c includes many of the same components as PD system 10a, which are numbered identically and include all of the structures, functions, and alternatives to those components described above. In particular, system 10c includes a circulator 20 and a control unit 100 having one or more processors 102, one or more memories 104, a video controller 106, and a user interface 108. System 10c includes an inline dialysis fluid heater 56, reusable lines or tubes 52a and 52b, PD fluid supply valves 54a to 54d, an air collector 60 operating with corresponding upper and lower level sensors 62a and 62b, a disinfecting fluid valve 54e, a gas line valve 54g positioned along a gas line 52g, a reusable line or tube 52c leading to a dialysis fluid pump 70, temperature sensors 58a and 58b, a pressure sensor 72a , 72b, 72c and 72d, respectively, reusable fresh patient tubing or lines 52f and used patient tubing or lines 52u, hose reel 28, double lumen reusable patient line 26, reusable discharge tube or line 52h extending to discharge line connector 34 and having discharge line valve 54h, exhaust line 52v having exhaust valve 54f, and reusable recirculation or sterilization tube or line 52d operating with corresponding sterilization valve 54s. A third recirculation or sterilization tube or line 52y extends between sterilization connectors 30c and 30d for use during sterilization. A fourth recirculation or sterilization tube or line 52z extends between sterilization connectors 30a and 30b for use during sterilization. The above-mentioned lines and components form a sterilization loop 90, which is sterilized after treatment. Each of the pump 70 , the heater 56 , the valves, and the sensors is controlled by the control unit 100 and / or outputs to the control unit 100 .

[0114] A major difference from system 10c is that the acid solution source 80, acid solution connector 82, and acid solution line 52i are located in the Figures 1 to 3 60. The position shown is moved so that the acid solution line 52i instead extends to the gas line 52g extending from the top of the air collector 60. The recirculation or sterilization tube or line 52y accordingly extends directly between the sterilization connectors 30c and 30d, rather than extending to the three-way acid solution valve 54i in the system 10a, which is removed in the system 10c. Two two-way acid solution valves 54j and 54k are provided along the acid solution line 52i, adding redundancy to ensure that the acid solution (such as citric acid) does not leak or otherwise flow into the treatment path (e.g., into the fresh PD fluid lumen of the lines 52c, 52f and the double-lumen reusable patient line 26) during treatment.

[0115] Another additional device found in the system 10c is a start-up sensor 74 output to the control unit 100, wherein in the illustrated embodiment, the start-up sensor 74 is located along the gas pipeline 52g, but may alternatively be located along the acid solution pipeline 52i. The start-up sensor 74 is configured to detect CO 2 Whether gas and acidic substance (e.g., citric acid) or PD fluid (mixed with acidic substance) are located in gas line 52g and / or acidic solution line 52i, for example, flowing in gas line 52g and / or acidic solution line 52i. In various embodiments, the start sensor 74 is an ultrasonic, optical, inductive, capacitive, or magnetic sensor output to the control unit 100.

[0116] Testing has shown that using citric acid as a descaling agent and heating the sanitized PD fluid to 85°C, for example, when 2.1 ml of 50% (by weight) citric acid is added to 300 ml (the approximate volume of the sanitizing loop 90) of bicarbonate-containing PD fluid, 110 ml of CO will be generated. 2 An advantage of the location of the acid solution source 80, the acid solution connector 82, and the acid solution line 52i in the system 10c is that the sterilization product gas, such as carbon dioxide (“CO 2 ”), can be transported and held in the empty space of the acidic solution source 80. In one embodiment, the container 80 for the acidic solution source is flexible, such as a polymer bag made of any of the materials discussed herein, which is flexible when receiving CO 2 The gas can expand and remove CO from the bag 2 It can shrink when it is in gas.

[0117] During post-treatment disassembly of the system 10c, the patient or user connects the distal end 26d of the reusable patient line 26 to the patient line connector 32 disposed at the housing 22, and connects the distal end 24e of the reusable PD fluid supply line 24a to 24d to the sterile connectors 30a to 30d (e.g., Figure 6 ) and removes the disposable drain line 36, sealingly closing the removable (e.g., rotatable or slidable) drain connector cap on the drain line connector 34. The control unit 100 then energizes valves 54e, 54j, 54k, 54f, and 54s to open, and causes the PD fluid pump 70 to draw a desired amount of descaling fluid, such as 50% (by weight) citric acid, from the acid solution source 80 and deliver it to the disinfection loop 90. The control unit 100 also reads the output of the start sensor 74 to confirm that the citric acid has been injected into the PD fluid within the commanded number of strokes of the PD fluid pump 70.

[0118] The control unit 100 then energizes valves 54e, 54f, 54s, 54b, and 54c to open, and causes the PD fluid heater 56 to heat the PD fluid mixed with citric acid to the desired disinfection temperature, e.g., 85°C, and causes the PD fluid pump 70 to circulate the heated PD fluid around the disinfection loop 90, e.g., in a timed manner, so that the appropriate amount of disinfection occurs. During the disinfection procedure, the control unit 100 may switch any desired valves and reverse the flow direction of the PD fluid pump 70 one or more times.

[0119] During sterilization of the sterilization loop 90, and possibly for a period of time before and / or after such sterilization, the control unit 100 is capable of entering a pressure release mode. In one embodiment, the control unit 100 enters a pressure release mode when one or more pressures measured by one or more pressure sensors 72a to 72d positioned along the sterilization loop 90 reach or achieve a threshold pressure (e.g., 10 kPa (1.5 psig)) or a certain pressure differential above the sterilization operating pressure, as described herein. The control unit 100 may also read the output of the upper level sensor 62a to ensure that the level of the PD fluid within the air collector 60 is below the upper level sensor 62b. The control unit 100 then energizes the citric acid valves 54j and 54k to open to allow the pressurized CO to flow into the air collector 60. 2 Gas flows into the container of the acid solution source 80. During this time, the control unit 100 also checks the output of the start sensor 74 to confirm that gas, rather than fluid, is present and flowing. If fluid is detected, the control unit 100 causes the citric acid valves 54j and 54k to close. When the pressure measured by one or more pressure sensors 72a to 72d drops to or below a threshold pressure (e.g., 10 kPa (1.5 psig)), the control unit 100 causes the citric acid valves 54j and 54k to close to prevent PD fluid from flowing into the container of the acid solution source 80. In addition, in one embodiment, if the output from the upper liquid level sensor 62a to the control unit 100 indicates that the PD fluid mixed with citric acid has reached the upper liquid level sensor 62b, the control unit 100 causes the citric acid valves 54j and 54k to close. In one embodiment, the control unit 100 is configured to enter the pressure release mode as many times as needed during the sterilization procedure (and possibly slightly before and / or after the sterilization procedure).

[0120] After the sterilization procedure, the control unit 100 no longer monitors the pressure measured by the one or more pressure sensors 72a to 72d for sterilization product gas overpressure. 2The gas remains in the container of the acid solution source 80 until the next treatment, at which time a new disposable drain line 36 is connected to the drain line connector 34. The control unit 100 causes the citric acid valves 54j and 54k, valve 54g, and drain valve 54h to open, and causes the PD fluid pump 70 to draw CO from the container of the acid solution source 80. 2 The control unit 100 monitors the output of the start sensor 74 to confirm that the CO is being removed from the container of the acid solution source 80. 2 During the gas process, gas rather than fluid is present and flowing. The output of the start sensor 74 (sensing citric acid or other acidic substances) and / or one or more pressure sensors (such as pressure sensor 72b) can be monitored by the control unit 100 to know when to stop the PD fluid pump 70 from pumping CO from the container of the acid solution source 80. 2 Then, before starting the next treatment, the PD fluid is activated to exhaust any CO remaining in the sterilization loop 90. 2 gas.

[0121] The above is used to convert CO 2 The depressurization process for gas removal into the acid solution source 80 vessel is described as being by CO 2 The overpressure caused by the gas formation is triggered. It is also noted that the decompression sequence can be performed once or multiple times. As with system 10a, in various embodiments of system 10a, (i) the triggering of the decompression sequence and (ii) the appropriate dissipation of CO 2 The total amount of time required for the gas pressure to be maintained may be a function of and dependent upon any one or more of the following parameters: (a) the sensed pressure in the sterilization loop 90, (b) the time since the CO 2 the amount of time that has passed since the start of gas production or since the end of a previous depressurization procedure, (c) the amount of CO to be dissipated 2 The volume of gas (eg, calculated by the control unit 100 knowing the citric acid (or other acid) concentration and the temperature of the sterilizing fluid), and / or (d) the number of previous decompression procedures that have occurred.

[0122] Reference now Figure 7 , showing the system 10c of the present disclosure using the release of CO 2 10c. The top line (dashed line) is a baseline showing the pressure drop due to exhaust CO when the system 10c depressurization procedure is not performed. 2 The unlabeled lines are for a particular PD fluid sold by the assignee of the present disclosure, namely Dianeal ®PD fluids that do not contain bicarbonate and therefore do not require the injection of a descaling fluid, such as citric acid, during the disinfection process. The delta-line and x-line are examples of PD fluids containing bicarbonate (e.g., Physioneal ® Here, after 2.1 ml of 50% (by weight) citric acid is added to the PD fluid (e.g., 300 ml) for heating and sterilization, the pressurized CO 2 The gas is released into the container of the acid solution source 80. As shown in the figure, due to the exhaust gas CO 2 The resulting pressure increase is mitigated and repeatedly reduced along both the delta-line and x-line curves. For both the delta-line and x-line curves, the output of the upper level sensor 62a working with the air collector 60 is used as the CO 2 The Δ-line shows that at the beginning of the sterilization process, when the air collector 60 is filled with PD fluid to the upper level sensor 62a, the CO 2 Only a portion of the gas is released into the acid solution source 80. The x-line shows a more preferred curve in which some gas (e.g., air) is already present in the air collector 60 at the beginning of the sterilization process. Here, CO can be performed during the entire sterilization process. 2 The evacuation of the gas thus produces a lower pressure curve than the pressure curve of the delta-line.

[0123] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. It is therefore intended that the appended claims cover such changes and modifications.

Claims

1. A peritoneal dialysis ("PD") system comprising: PD fluid pump; a sterilization loop, the sterilization loop including the PD fluid pump, the sterilization loop allowing PD fluid to be used to sterilize the sterilization loop; an air collector positioned along the disinfection loop; at least one gas valve positioned along at least one gas line leading to an upper portion of the air collector; a pressure sensor positioned and arranged to sense PD fluid pressure in the sterilization loop during a sterilization procedure; and A control unit to which the pressure sensor outputs, the control unit being configured to cause the at least one gas valve to open when the PD fluid pressure in the sterilization loop reaches or exceeds a threshold PD fluid pressure due to gas formation caused during the sterilization procedure.

2. The PD system according to claim 1, wherein: The gas formation is induced by mixing the PD fluid with an acidic solution.

3. The PD system according to claim 1, wherein: The control unit is configured such that, before causing the at least one air valve to open, the control unit checks that the PD fluid level in the air collector is not too high.

4. The PD system of claim 1, comprising a drain line for draining spent PD fluid during treatment, and wherein: Leaving the at least one gas valve open allows PD fluid pressure due to the gas formation to dissipate toward the exhaust line.

5. The PD system according to claim 1, wherein: The control unit is further configured to, when the PD fluid pressure reaches or exceeds the threshold PD fluid pressure, at least one of: (i) close at least one PD fluid valve positioned adjacent to the air collector, or (ii) stop the PD fluid pump.

6. The PD system according to claim 1, wherein: The pressure sensor is positioned along one of the at least one gas line in fluid communication with the sterilization loop, thereby allowing the pressure sensor to sense PD fluid pressure during the sterilization procedure.

7. The PD system according to claim 1, wherein: After opening the at least one gas valve, the pressure sensor or a second pressure sensor output to the control unit senses PD fluid pressure dissipation, and the control unit is further configured to close the at least one gas valve and continue the sterilization procedure when receiving an output indicating PD fluid pressure dissipation.

8. The PD system of claim 1, wherein the PD system is configured such that opening of the at least one gas valve allows gas to dissipate from an upper portion of the air collector through one of the at least one gas lines toward a discharge port.

9. The PD system according to claim 1, wherein: The control unit is further configured to open the at least one gas valve or keep the at least one gas valve open for a certain amount of time based on one or more of the following data: (i) the volume of gas, (ii) the duration since the start of gas formation, and / or (iii) the number of times the control unit has previously opened the at least one gas valve.

10. A peritoneal dialysis ("PD") system comprising: PD fluid pump; a sterilization loop, the sterilization loop including the PD fluid pump, the sterilization loop allowing PD fluid to be used to sterilize the sterilization loop; an acidic solution source containing an acidic substance for use during a sterilization procedure; a drain line positioned and arranged to drain spent PD fluid during treatment; Gas pipelines; at least one gas valve positioned along the gas line, the at least one gas valve allowing fluid communication between the gas line and the exhaust line; a pressure sensor positioned and arranged to sense PD fluid pressure in the sterilization loop during a sterilization procedure; and a control unit to which the pressure sensor outputs, the control unit being configured to cause the at least one gas valve to open when a PD fluid pressure in the sterilization loop reaches or exceeds a threshold PD fluid pressure due to gas formation caused by mixing the PD fluid and the acidic substance during the sterilization procedure, and wherein opening the at least one gas valve allows the PD fluid pressure caused by gas formation to dissipate toward the exhaust line.

11. The PD system of claim 10, comprising a heater configured to heat the PD fluid and the acidic substance to a sterilization temperature during the sterilization procedure.

12. The PD system according to claim 10, wherein: The PD fluid includes bicarbonate, and the gas formed is carbon dioxide ("CO 2 ") gas.

13. The PD system of claim 10, wherein the PD system is configured such that: opening of the at least one gas valve allows gas to dissipate from an upper portion of the air collector through one of the at least one gas lines toward the exhaust line.

14. The PD system according to claim 10, wherein: The control unit is configured such that, before causing the at least one air valve to open, the control unit checks that the PD fluid level in the air collector is not too high.

15. The PD system according to claim 10, wherein: The control unit is further configured to open the at least one gas valve, or to keep the at least one gas valve open for a certain amount of time, based on one or more of the following data: (i) the volume of gas, (ii) the duration since the start of gas formation, and / or (iii) the number of times the control unit has previously opened the at least one gas valve.

16. The PD system according to claim 10, wherein: The control unit is further configured to maintain, at the beginning of metered delivery of acidic substance for the disinfection procedure, a pressure at the acidic solution source equal to a pressure recorded at the acidic solution source at the end of metered delivery of acidic substance for a previous disinfection procedure.

17. A peritoneal dialysis ("PD") system comprising: PD fluid pump; a sterilization loop, the sterilization loop including the PD fluid pump, the sterilization loop allowing PD fluid to be used to sterilize the sterilization loop; an air collector positioned along the disinfection loop; at least one gas valve positioned along at least one gas line leading to an upper portion of the air collector; a pressure sensor positioned and arranged to sense PD fluid pressure in the sterilization loop during a sterilization procedure; and A control unit to which the pressure sensor outputs, the control unit being configured to: when the PD fluid pressure in the sterilization loop reaches or exceeds a threshold PD fluid pressure due to gas formation caused during the sterilization procedure, the control unit causes the at least one gas valve to open and causes the PD fluid pump to pump a certain amount of gas from the air collector.

18. The PD system of claim 17, comprising a patient line valve positioned along the patient line, and wherein: When the PD fluid pump pumps the amount of gas from the air collector, the control unit causes the patient line valve to open.

19. The PD system of claim 17, comprising a discharge line valve positioned along the discharge line, and wherein: After the PD fluid pump pumps the amount of gas from the air collector, the control unit closes the patient line valve and opens the drain line valve to deliver gas to the drain line.

20. The PD system according to claim 17, wherein: The control unit is further configured to open the at least one gas valve and cause the PD fluid pump to pump, or to keep the at least one gas valve open for a certain amount of time while the PD fluid is pumped, based on one or more of the following data: (i) the volume of gas, (ii) the duration since the start of gas formation, and / or (iii) the number of times the control unit has previously opened the at least one gas valve.

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