Peritoneal dialysis system with carbon dioxide input to inhibit and / or remove calcium carbonate formation - Patent Application 20070123333

Abstract

A peritoneal dialysis ("PD") system includes a PD fluid pump, a sterilization loop including the PD fluid pump, the sterilization loop including a PD fluid used to sterilize the sterilization loop, and a carbon dioxide (CO2) source positioned and arranged to supply CO2 to the sterilization loop to inhibit and / or remove calcium carbonate (CaCO3) production during a sterilization sequence. The PD system includes a control unit configured to open a valve to allow the CO2 to be supplied, where the control unit may use a lookup table or algorithm to determine a desired pressure or pressure rise.

Description

[Technical field]

[0001] Priority claim This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 293,383, filed December 23, 2021, entitled "PERITONEAL DIALYSIS SYSTEM HAVING CARBON DIOXIDE INJECTION TO INHIBIT / REMOVE CALCIUM CARBONATE," the entire contents of which are incorporated herein by reference.

[0002] background FIELD OF THE DISCLOSURE The present disclosure relates generally to medical fluid procedures, and more particularly to dialysis fluid procedures. [Background technology]

[0003] Due to a variety of causes, a person's renal system can fail. Renal failure results in several physiological derangements. It is no longer possible to maintain water and mineral balance or to excrete the daily metabolic load. Toxic end products of metabolism (e.g., urine, creatinine, uric acid and others) can accumulate in the patient's blood and tissues.

[0004] Reduced kidney function and, above all, kidney failure are treated with dialysis. Dialysis removes waste, toxins, and excess water from the body that normal functioning kidneys would otherwise remove. Dialysis treatment for replacement of kidney function is vital for many people because the treatment is life-saving.

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

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

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

[0008] Most HD, HF, and HDF procedures occur in centers. Recently, there has been a trend toward home hemodialysis ("HHD"), in part because HHD may be performed daily, offering therapeutic benefits over in-center hemodialysis procedures that typically occur two to three times a week. Studies have shown that more frequent procedures remove more toxins and waste products and overload the interdialysate less than patients who receive less frequent but perhaps longer procedures. Patients who receive more frequent procedures do not experience as much vicious circulation (fluid and toxin swings) as in-center patients who have two to three days' worth of accumulated toxins prior to the procedure. In some areas, the nearest dialysis center may be many miles away from the patient's home, causing door-to-door procedure times to take up a large portion of the day. Procedures at centers closer to the patient's home may also take up a large portion of the patient's day. HHD may be performed overnight or during the day when the patient is relaxing, working, or otherwise productive.

[0009] Another type of renal failure treatment is peritoneal dialysis ("PD"), in which a dialysis solution (also called dialysis fluid) is infused via a catheter into a patient's peritoneal chamber. The dialysis fluid contacts the peritoneal membrane in the patient's peritoneal chamber. Waste, toxins, and excess water leave the patient's bloodstream, pass through capillaries in the peritoneal membrane, and enter the dialysis fluid by diffusion and osmosis; an osmotic gradient occurs across the membrane. An osmotic agent in the PD dialysis fluid provides the osmotic gradient. Spent, or used, dialysis fluid is flushed from the patient, removing waste, toxins, and excess water from the patient. This cycle may be repeated, for example, multiple times.

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

[0011] Automated peritoneal dialysis ("APD") is similar to CAPD in that the dialysis treatment includes drain, fill, and dwell cycles. However, APD machines perform the cycles automatically, typically while the patient sleeps. APD machines free the patient from having to manually perform the treatment cycles and from having to transport the supply during the day. APD machines fluidly connect to an implanted catheter, a source or bag of fresh dialysis fluid, and a fluid drain. The APD machine pumps fresh dialysis fluid from the dialysis fluid source through the catheter and into the patient's peritoneal chamber. The APD machine also allows the dialysis fluid to remain in the chamber and for waste, toxins, and excess water to move out. The source may include several liters of dialysis fluid with several solution bags.

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

[0013] In any of the above mentioned modes of using an automated machine, the automated machine operates with a disposable set that is typically discarded after a single use. Depending on the complexity of the disposable set, the cost of using one set per day can be significant. Also, daily disposal requires space for storage, which can be a nuisance for homeowners and businesses. Furthermore, daily disposable alternatives require daily set-up time and effort by the patient or caregiver at home or clinic.

[0014] For each of the reasons discussed above, it would be desirable to provide an APD machine that reduces disposable waste. In so doing, to the extent that calcium carbonate precipitates are produced by sterilization, such precipitates present a problem that can grow over time. Accordingly, there is a need for a PD system that has a method for inhibiting calcium carbonate formation and / or a method for removing the same if it is produced. Summary of the Invention [Means for solving the problem]

[0015] Abstract Known automated peritoneal dialysis ("PD") systems typically include a machine or cycler that accepts and operates a pumping cassette having a rigid portion and a deformable flexible portion for performing pumping and valving. The rigid portion is attached to tubing that extends to various bags. The disposable cassette and associated tubing and bags can be cumbersome for a patient at home to wear for a treatment. The overall volume of disposable products can also lead to multiple set-up procedures requiring input from the patient, which can expose the potential for error.

[0016] On the other hand, the disclosed APD system and associated methodology converts many of the fluid-carrying parts of the PD system into reusable components that are sterilized after treatment. The fluid lines in the machine or cycler are reused. The remaining disposable products may include a drain line leading to a drain bag or house drain and one or more PD fluid containers or bags (e.g., different dextrose or glucose level PD fluid containers and a final bag container (containing icodextrin, etc.)). In an embodiment, a disposable filter is placed at the distal end of the patient line to provide a final stage of PD fluid filtration before delivery to the patient.

[0017] The APD system of the present disclosure includes an APD cycler 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 lines can be connected to a sterile connector supported and provided by the housing. The reusable PD fluid lines can extend, for example, from the front of the housing and connect to a sterile connector also provided at the front of the housing for easy access to the PD fluid lines. The reusable PD fluid lines can be color coded and / or keyed to match colored or keyed connectors of the PD fluid container or bag. The container or bag can hold different dextrose or glucose level PD fluids (e.g., 1.36% glucose PD fluid, 2.27% glucose PD fluid, 3.86% glucose PD fluid, and / or a final bag of PD fluids with different formulations such as icodextrin). The PD fluid can contain a bicarbonate component.

[0018] Inside the housing, reusable tubing runs from each reusable PD fluid line, through a PD fluid supply valve for each PD fluid line, to a PD fluid in-line heater. In an embodiment, each valve of the APD cycler is an electrically actuated valve with a reusable valve body that prevents (e.g., when unpowered) and allows (e.g., when powered) PD fluid to flow through the body. The PD fluid in-line heater is also electrically actuated in one embodiment, and is, for example, a resistive heater with a reusable heater body that receives PD fluid for heating. The in-line heater in an embodiment can heat PD fluid from room temperature to body temperature (e.g., 37° C.) at a flow rate of at least 200 milliliters (ml) / min. A temperature sensor is located adjacent to the heater (e.g., downstream of the heater) to provide feedback for temperature control.

[0019] The reusable tubing, in one embodiment, runs from the outlet of the PD fluid in-line heater to the air trap. Any of the tubing inside the cycler housing can be metal (e.g., stainless steel) or plastic (e.g., polyvinyl chloride ("PVC") or non-PVC materials such as polyethylene ("PE"), polyurethane ("PU"), polycarbonate ("PC"), etc.). In an embodiment, one or more level sensors are located adjacent to the air trap so that a desired level or range of levels of PD fluid are maintained in the air trap. A fluid line valve, in an embodiment, is located along the reusable fluid line downstream of the air trap. At least one gas line valve located along at least one gas line can also be provided. The air trap can be closed upstream by a PD fluid supply valve to drain the air trap when indicated by the output of the level sensor.

[0020] The reusable PD fluid pump comprises a reusable pump body that is located within the cycler housing and receives the PD fluid for pumping. That is, the pump does not require the PD fluid to flow within a disposable product, such as a tube or cassette. The PD fluid pump may be an electrically actuated piston pump that is inherently accurate enough that a separate PD fluid volume measuring device, such as a flow meter, balance chamber, or device using the ideal gas law, is not required. The PD fluid pump may instead be an electrically actuated gear pump or centrifugal pump that can operate with a separate PD fluid volume measuring device.

[0021] The PD fluid pump is controllable to pump to and from the patient at or below a pressure limit by controlling the level of current in the PD fluid pump. The positive patient pressure limit can be, for example, 1 to 5 psig, such as 2 psig (14 kPa). The negative patient pressure limit can be, for example, -1.0 psig to -3.0 psig, such as -1.3 psig (-9 kPa). The PD fluid pump, in one embodiment, is bidirectional and continuous so that one pump can be provided.

[0022] The APD cycler of the disclosed APD system includes a control unit having one or more processors and one or more memories that receives signals or outputs from the pressure sensor, temperature sensor, and optionally the conductivity sensor, and processes 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 safe system limits during sterilization. The control unit uses temperature feedback to control the PD fluid heater to heat unused PD fluid, such as to body temperature.

[0023] The control unit also opens and closes PD fluid valves in combination with the PD fluid pump and heater to perform a priming sequence, a patient fill sequence, a patient drain sequence, and a sterilization sequence after a PD treatment, where each of the at least one reusable PD fluid supply lines is connected to one of the at least one sterilization connectors, and where the reusable patient line is connected to the reusable patient line connector. The sterilization sequence prepares the APD cycler for the next treatment. In an embodiment, unused PD fluid is heated after the last drain and used for sterilization.

[0024] The use of unused PD fluids containing bicarbonate as sterilizing fluids can lead to the formation of calcium carbonate in the sterilized flow paths and flow components of the PD machine or cycler (which constitutes the sterilization loop). In response, the present system includes a source carbon dioxide (CO) injected during sterilization to prevent and / or remove calcium carbonate formation. 2 ) is provided. 2 In one embodiment, the source is CO 2 Valve-controlled CO 2 The fluid is placed in fluid communication with the line.

[0025] The control unit, in one embodiment, is programmed to execute a sequence that relies on a table stored in one or more memories of the control unit. 2 Pressure increase due to injection or CO 2 The total pressure to be achieved by the input is set as a function of at least one of the solution bicarbonate composition and / or the sterilization temperature setting. Generally, the more bicarbonate there is in the PD fluid, the greater the amount of CO introduced. 2 More pressure is required depending on the gas. Also, generally, the higher the sterilization PD fluid temperature, the lower the introduced CO 2 Higher pressures are required for some gases. 2 The source is CO for many sterilization sequences. 2 CO 2 CO 2 How much CO is needed to effectively block the formation of calcium carbonate precipitates while using gas? 2 To determine what gas pressure is required, experiments and / or calculations are performed varying bicarbonate levels for various sterilization temperatures.

[0026] In another embodiment, the table may include a CO2 ratio that is dependent on the type of sterilization fluid, such as the PD fluid, the temperature of the PD fluid, and the pressure of the PD fluid. 2where the mole fraction values ​​lie in a space corresponding to a given temperature and pressure. 2 The desired amount of CO is added to the water contained in the PD fluid to be sterilized. 2 The addition of CO (e.g., in mmol) is determined from the chemical equation that creates carbonic acid, which when combined with calcium carbonate, causes a chemical reaction that splits the calcium carbonate into calcium and bicarbonate ions that are suspended in the PD fluid and carried to a drain. Here, the control unit calculates the amount of CO (e.g., in mmol) 2 To achieve the desired amount of CO 2 The table is used to determine how much the sterilizing fluid pressure needs to be increased by the introduction of 1.36% glucose PD fluid, 2.27% glucose PD fluid, 3.86% glucose PD fluid, etc. In an embodiment, a separate mole fraction table is stored and accessible by the control unit for each possible sterilizing or PD fluid, such as a first 1.36% glucose PD fluid, a second 2.27% glucose PD fluid, a third 3.86% glucose PD fluid, etc.

[0027] CO 2 The first step to introduce CO into the sterilization loop occurs when the procedure is complete and it is time for the control unit to perform sterilization. 2 In one embodiment, with the valves closed, the PD fluid pump not activated, and the heater not powered, the control unit accesses a look-up table (or corresponding algorithm) that sets the pressure (or pressure rise) to be achieved as a function of the bicarbonate level in the PD fluid used for sterilization and / or the sterilizing fluid temperature. In another embodiment, the control unit selects the initial CO2 pressure from a stored table for the particular sterilizing fluid used. 2 To obtain mole fraction values, initial pressure and temperature measurements are performed. Alternatively or in addition, CO 2 Optional pH sensor or CO sensor to determine mole fraction 2 Although a sensor may be provided and used, a look-up table for a particular sterilizing fluid would fill and eliminate the need for an extra sensor.2 The pressure or pressure rise to be achieved by the gas input is obtained and used.

[0028] CO 2 The second step of introducing CO occurs with the PD fluid pump not activated and the heater not powered. 2 Open the valve and CO 2 The control unit allows CO to be injected into the PD fluid in the sterilization loop. 2 In either case, the control unit monitors the output of the pressure sensor and initiates CO injection when the pressure has achieved the required pressure rise or total pressure as determined from any of the look-up tables described herein. 2 Stop the injection of

[0029] CO 2 The third step is to introduce CO in any of the alternative ways described herein and with elevated CO 2 This occurs in that the control unit causes the PD fluid heaters to be de-energized and the PD fluid pumps to be de-activated to circulate heated sterilizing fluid (PD fluid) through the sterilizing loop at pressure. The heated sterilizing fluid circulation occurs for a specified period of time. During this period, a specified amount of CO at elevated pressure is circulated. 2 The presence of calcium carbonate (CaCO) is determined according to the chemical reactions described herein. 3 ) to impede or eliminate

[0030] CO 2 A fourth, possibly optional step of introducing CO occurs during which the control unit causes the PD fluid heater to be depowered but continues to allow the fluid pump to circulate the cooled PD fluid. During the cooling period, the control unit monitors the output of the pressure sensor to see if the output returns to the pressure level prior to heating. If CO 2 If any leak occurs, the pressure will rise to CO 2If the pressure falls below that after injection, the control unit may adjust the CO2 injection rate to allow additional CO2 to be injected, for example to re-attain a desired pressure rise above the initial start-up pressure. 2 If provided, ammonia and / or CO 2 The sensor detects additional CO 2 may additionally or alternatively be used here to aid in metering the amount of sterilization fluid into the sterilization loop.

[0031] In a first aspect of the present disclosure, which may be combined with any other aspect or portion thereof in view of the disclosure described herein and without limiting the disclosure in any manner, a peritoneal dialysis ("PD") system includes a PD fluid pump and a sterilization loop comprising the PD fluid pump, the sterilization loop comprising a PD fluid used to sterilize the sterilization loop, and a sterilization sequence for sterilizing the sterilization loop by dissolving calcium carbonate (CaCO3) in the sterilization fluid. 3 ) production and / or removal in the sterilization loop. 2 Carbon dioxide (CO 2 ), and sauce.

[0032] In a second aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the PD system includes a sterilization loop and a CO 2 CO located between the source 2 Equipped with a valve, CO 2 The valve is CO 2 is opened to allow for the supply of sterilization fluid to the sterilization loop.

[0033] In a third aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the PD system is configured to supply CO2 to a desired pressure or pressure increase to inhibit and / or remove calcium carbonate formation during a sterilization sequence. 2 to allow the PD fluid to be pressurized 2 A control unit is provided that is configured to cause the valve to open.

[0034] In a fourth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a PD system includes at least one pressure sensor having an output to a control unit, the control unit configured to monitor the at least one pressure sensor output to detect a desired pressure or pressure increase.

[0035] In a fifth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit is configured to use a look-up table to determine the desired pressure or pressure rise.

[0036] In a sixth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit stores a sterilization temperature to which the PD fluid is heated for the sterilization sequence, and a desired pressure or pressure rise in the look-up table corresponds to the sterilization temperature.

[0037] In a seventh aspect of the present disclosure which may be combined with any other aspect or portion thereof, the PD system includes at least one temperature sensor having an output to a control unit, the control unit being configured to monitor the at least one temperature sensor output to detect a sterilization temperature.

[0038] In an eighth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the look-up table is specific to the type of PD fluid used for sterilization.

[0039] In a ninth aspect of the present disclosure, which may be combined with any other aspect or portion thereof, the control unit detects the bicarbonate level of the PD fluid used for sterilization, and a desired pressure or pressure increase in the lookup table corresponds to the bicarbonate level.

[0040] In a tenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit controls the sterilization loop to receive CO 2and the control unit is configured to obtain an initial pressure and temperature reading prior to supplying CO 2 contained in the sterilization loop using the lookup table and the initial pressure and temperature readings. 2 The method is further configured to determine an initial amount of

[0041] In an eleventh aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit is configured to use an algorithm to determine a desired pressure or pressure increase.

[0042] In a twelfth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit may further include a step of controlling a CO 2 to pressurize the PD fluid to a desired pressure or pressure increase. 2 The valve is configured to open.

[0043] In a thirteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit controls the CO 2 to pressurize the PD fluid to a desired pressure or pressure increase. 2 The valve is configured to open.

[0044] In a fourteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a PD system includes a PD fluid heater, where the control unit controls the PD fluid heater to heat the PD fluid during a sterilization sequence by controlling the PD fluid heater to heat the PD fluid by CO 2 to pressurize the PD fluid to a desired pressure or pressure increase. 2 The valve is configured to open.

[0045] In a fifteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, a PD system includes a PD fluid heater, wherein the control unit controls the PD fluid heater to heat a PD fluid during a sterilization sequence by controlling CO 2 to pressurize the PD fluid to a desired pressure or pressure increase. 2 The valve is configured to open.

[0046] In a sixteenth aspect of the present disclosure that may be combined with any other aspect or portion thereof, the control unit controls the CO 2 to pressurize the PD fluid during the cooling period. 2 The valve is configured to open.

[0047] In a seventeenth aspect of the present disclosure which may be combined with any other aspect or portion thereof, any of the features, functions, and alternatives described in association with any one or more of Figures 1-7 may be combined with any of the features, functions, and alternatives described in association with any other of Figures 1-7.

[0048] It is therefore an advantage of the present disclosure to provide a system for an automated peritoneal dialysis ("APD") cycler that helps ensure that calcium carbonate production is inhibited or scavenged away during sterilization.

[0049] Carbon dioxide (CO) is added during pasteurization to prevent or eliminate the development of calcium carbonate. 2 It is another advantage of the present disclosure to provide a system for an APD cycler that efficiently uses

[0050] It is a further advantage of the present disclosure to provide a system for an APD cycler that helps prevent precipitate build-up during sterilization.

[0051] Additional features and advantages are described in and will be apparent from the following detailed description and figures. The features and advantages described herein are not all-inclusive, and in particular, many additional features and advantages will be apparent to those skilled in the art in view of the figures and descriptions. Likewise, any particular embodiment need not have all of the advantages recited herein, and it is expressly contemplated that each advantageous embodiment may be separately claimed. Moreover, it should be noted that the language used in the specification has been selected primarily for readability and educational purposes, and not to limit the scope of the inventive subject matter. [Brief description of the drawings]

[0052] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of an automated peritoneal dialysis ("APD") machine or cycler and associated systems of the present disclosure.

[0053] [Diagram 2] FIG. 2 is a simplified schematic diagram of one embodiment of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure after treatment and before sterilization.

[0054] [Diagram 3] FIG. 3 is a simplified schematic diagram of one embodiment of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure that delivers CO2 to a sterilization loop.

[0055] [Figure 4] FIG. 4 is a simplified schematic diagram of one embodiment of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure that pumps heated PD sterilizing fluid containing delivered CO2 during sterilization.

[0056] [Diagram 5] FIG. 5 is a simplified schematic diagram of one embodiment of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure that optionally delivers CO2 to a sterilization loop during the cooling period.

[0057] [Figure 6] FIG. 6 is an example look-up table stored in a control unit of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure, the look-up table providing the pressure or pressure increase to be achieved by CO2 input, where the pressure is based on at least one of the amount of bicarbonate in the PD sterilizing fluid and / or the sterilizing fluid temperature.

[0058] [Figure 7] FIG. 7 is an example of an alternative lookup table stored in a control unit of an automated peritoneal dialysis ("APD") machine or cycler of the present disclosure, where the lookup table provides the pressure or pressure increase to be achieved by CO2 input, where the pressure is based on the mole fraction of CO2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] Detailed Description System Overview Referring now to the drawings, and in particular to FIG. 1, an automated peritoneal dialysis ("APD") system 10 and associated methodology of the present disclosure includes an APD machine or cycler 20. The system 10 and cycler 20 attempt to eliminate as many disposable products as possible, instead providing the majority of fluid carrying parts as reusable components that are sterilized after treatment. The fluid lines within the machine or cycler are reused. In particular, FIG. 1 illustrates that the cycler 20 includes a housing 22 from which extend reusable PD fluid supply lines 24a-24d. FIG. 1 further illustrates that a reusable patient line 26 also extends from the housing 22 of the machine or cycler 20. The reusable patient line 26, which is typically longer than the reusable PD fluid supply lines 24a-24d, may be coiled or wound within the housing by a spool or hose spool 28 when the reusable patient line 26 is not connected to a patient for treatment.

[0060] When not connected to a PD fluid container or bag, the reusable PD fluid supply lines 24a-24d and patient line 26 can be connected to dedicated connectors provided supported by the housing 22. The reusable PD fluid supply lines and patient lines may extend, for example, from the front of the housing 22 and connect to connectors also provided at the front of the housing to provide access to the PD fluid and patient lines. In the illustrated embodiment, the distal ends 24e of the PD fluid supply lines 24a-24d are releasably attached in a fluid-tight manner to sterile connectors 30a-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. The sterile connectors 30a-30d are configured in one embodiment to automatically close or snap when the reusable PD fluid supply lines 24a-24d are removed or not connected to the connectors, and the patient line connector 32 is configured in one embodiment to automatically close or snap when the reusable patient line 26 is removed or not connected to the connectors.

[0061] 1 also illustrates that the housing 22 provides a drain line connector 34 that may be releasably covered by a movable (e.g., rotatable or slidable) cover 34c. The drain line connector 34 receives a disposable drain line 36 for the procedure that may run to a drain connector or bag or to a house drain. The disposable drain line 36 is disconnected from the drain line connector 34 during sterilization.

[0062] Disposable PD fluid or solution containers or bags (not shown as system 10 is in a sterile configuration with the containers or bags removed) are connected to reusable PD fluid supply lines 24a-d, respectively. Distal ends 24e of reusable PD fluid supply lines 24a-d may be color coded or keyed to match color coded or keyed connectors of dedicated PD fluid containers or bags. The containers or bags may hold the same or different dextrose or glucose level PD fluids, such as, for example, a 1.36% glucose PD fluid, a 2.27% glucose PD fluid, a 3.86% glucose PD fluid, and / or a final bag of a different formulation of PD fluid (e.g., icodextrin, etc.).

[0063] 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 one reusable PD fluid line and PD fluid container or more than one reusable PD fluid line and PD fluid container. In a further alternative embodiment, the PD fluid containers or bags are replaced with an on-line PD fluid generation source that connects to and is in fluid communication with one reusable PD fluid supply line.

[0064] Besides the disposable drain line 36 and associated container (if used), the only other disposable component of system 10 is believed in one embodiment to be a disposable filter set (not shown) that is releasably 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 an embodiment, the disposable filter set is interfaced between the distal end 26d of the reusable patient line 26 and the patient's transfer set which leads to an indwelling PD catheter that is inserted into the patient.

[0065] Any one, more, or all of the reusable PD fluid supply lines 24a-24d, the reusable patient lines 26, the sterile connectors 30a-30d, the patient line connector 32, the drain line connector 34, the drain line 36, the PD fluid container or bag, and the patient line filter set may be made from one or more plastics, such as polyvinyl chloride ("PVC") or non-PVC materials, such as polyethylene ("PE"), polyurethane ("PU"), polypropylene ("PP"), or polycarbonate ("PC").

[0066] FIG. 1 further illustrates that reusable supply tube 52a runs from each of reusable PD fluid supply lines 24a-d through PD fluid supply valves 54a-d, respectively, to PD fluid in-line heater 56. In one embodiment, each valve of APD cycler 20, including PD fluid supply valves 54a-d, is an electrically actuated valve having a reusable valve body that prevents (e.g., when unpowered for fail-safe operation) or allows (e.g., when powered) PD fluid to flow through the body. In the illustrated embodiment, valve 54d is a three-way valve having a normally open port for receiving PD fluid from reusable PD fluid supply lines 24b or 24c and a normally closed port for receiving PD fluid from reusable PD fluid supply line 24d. PD fluid in-line heater 56 is also electrically actuated in one embodiment and is a resistive heater having a reusable heater body that receives PD fluid, e.g., for treatment and for sterilization heating. In-line heater 56 in an embodiment is capable of heating the PD fluid from room temperature or colder temperatures (e.g., when the PD fluid is stored in a cold environment) to body temperature (e.g., 37° C.) at a flow rate of at least 200 milliliters ("ml") per minute.

[0067] A first temperature sensor 58a is located adjacent to (e.g., downstream of) the in-line heater 56 to provide feedback for temperature control. Optionally, a second temperature sensor (not shown) can be provided upstream of the PD fluid heater 56 to allow the incoming temperature of the unused PD fluid to be taken into account in the heating algorithm. A second temperature sensor 58b is shown just downstream of the PD fluid pump 70, e.g., provided as a second check that the unused PD fluid leaving the PD fluid pump 70 is at the desired temperature for treatment (e.g., body temperature or 37° C.).

[0068] In the illustrated embodiment, the flow switch 68 is located immediately upstream of the PD fluid in-line heater 56. The output from the flow switch 68 is used to ensure that there is PD fluid flow through the in-line heater 56. When the output (or lack thereof) from the flow switch 68 indicates no or little PD fluid flow (which may harm the in-line heater 56 when powered), it causes the system 10 to stop powering the in-line heater 56 to stop the treatment or sterilization, as appropriate, while (i) attempting to find a remedy for the no or low flow situation or (ii) triggering an audible, visual, or audiovisual alarm or alert at the user interface 108. Alternative methods for ensuring flow to the in-line heater 56 to power the heater may instead be used.

[0069] Reusable tube 52b runs from the outlet of PD fluid in-line heater 56 to air trap 60 in the illustrated embodiment of FIG. 1. Any of the reusable tubing inside the housing of cycler 20, including reusable tubes 52a and 52b, may be made of metal, such as stainless steel, or plastic, such as polyvinyl chloride ("PVC") or non-PVC materials (e.g., polyethylene ("PE"), polyurethane ("PU"), polypropylene ("PP"), polyetheretherketone ("PEEK"), or polycarbonate ("PC"), etc.). In an embodiment, one or more level sensors 62a and 62b detect the desired level or is located adjacent to air trap 60 so that a range of levels may be maintained within the air trap. Fluid line valve 54e is located downstream of air trap 60 in the illustrated embodiment to receive fresh, heated PD fluid from the air trap. Gas line valve 54g is located along gas line 52g extending from the top of air trap 60. Air trap 60 may be closed upstream by PD fluid supply valves 54a-54d to drain the air trap when indicated by the output of level sensors 62a or 62b.

[0070] The reusable fluid line 52c runs between the fluid line valve 54e and a PD fluid pump 70 located within the housing 22 of the cycler 20, and the gas line 52g runs between the gas line valve 54g and a PD fluid pump 70 located within the housing 22 of the cycler 20. The PD fluid pump 70 comprises a reusable pump body that receives the PD fluid for pumping. That is, the pump 70 does not require the PD fluid to flow within a disposable product such as a tube or cassette. The reusable pump body of the pump 70 itself receives the PD fluid. The PD fluid pump 70 can be of the type of piston pump, for example, that is inherently accurate enough that a separate PD fluid volume measuring device such as a balance chamber or flow meter is not required. The PD fluid pump 70 can instead be a less accurate gear or centrifugal pump that works with a PD fluid volume measuring device. The PD fluid pump 70 is controllable to pump to and from the patient at or below the pressure limit by controlling the level of current to the PD fluid pump. The positive patient pressure limit may 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)). The PD fluid pump 70 may also be capable of providing lower pressures if needed (e.g., for small children or babies). The PD fluid pump 70, in one embodiment, is bidirectional and continuous so that one pump may be provided.

[0071] 1 further illustrates that a fresh PD fluid patient line valve 54f, in one embodiment, is located along the reusable fresh PD fluid patient tubing or line 52f between the downstream temperature sensor 58b and the spool or hose reel 28. The fresh PD fluid patient tubing or line 52f, in one embodiment, is in fluid communication with the fresh PD fluid lumen of the dual lumen reusable patient line 26. A used PD fluid patient line valve 54u, in one embodiment, is located along the reusable used PD fluid patient tubing or line 52u between the PD fluid pump 70 and the spool or hose reel 28 (via intersection 64a). The used PD fluid patient tubing or line 52u, in one embodiment, is in fluid communication with the used PD fluid lumen of the dual lumen reusable patient line 26. A drain line valve 54h is located along the reusable drain tubing or line 52h extending from the tee 66 to the drain line connector 34.

[0072] A first patient pressure sensor 72a is located along unused PD fluid patient tubing or line 52f between PD fluid pump 70 and spool or hose spool 28 to measure positive patient PD fluid pressure. A second patient pressure sensor 72b is located along gas line 52g to measure negative patient PD fluid pressure between the patient drain (the gas is at the same negative pressure as the used PD fluid via fluid communication at intersection 64a). A third and fourth pressure sensor 72c and 72d are located along reusable sterile tubing or line 52d.

[0073] As mentioned above, the patient line connector 32 is located in the APD cycler housing 22 to receive the dual lumen reusable patient line 26 during sterilization and generally while the patient is not undergoing treatment. The patient line connector 32 in one embodiment includes a sealed fluid U-turn or 180° turn that allows sterilizing fluid, such as heated PD fluid, to flow from one lumen of the dual lumen patient line to the other lumen of the dual lumen patient line. Thus, the dual lumen reusable patient line 26 is included in the sterilization loop.

[0074] As further described above, the drain line 36 is flexible and disposable in one embodiment, and connects to a drain line connector 34 extending from the housing 22 of the APD cycler 20 during treatment. After treatment, the drain line 36 may be removed during a sterilization sequence. The drain line connector 34 receives an internal, reusable drain tube or line 52h for delivering spent PD fluid to the drain line 36 during patient drainage. The drain line connector 34 allows for the delivery of air or carbon dioxide (CO2) to the drain line 36 during treatment. 2 )。 Vent tube or line 52v is also received for delivering gas such as . Vent valve 54v is located along vent tube or line 52v.

[0075] 1, reusable sterilization tube or line 52d extends to second intersection 64b along with vent tube or line 52v and used PD fluid patient tube or line 52u. Reusable sterilization tube or line 52d includes sterilization valve 54s. During a procedure, sterilization tube or line 52d handles sterilized fluid, e.g., unused heated PD fluid, vent tube or line 52v handles vent gas, e.g., air, while used PD fluid patient tube or line 52u handles used PD fluid.

[0076] 1 is located between sterile connectors 30c and 30d for use during sterilization. A similar bypass line 52z is provided between sterile connectors 30a and 30b. During sterilization, heated sterile fluid, such as PD fluid, is directed through bypass lines 52y and 52z to the fully sterile sterile connectors 30a-30d.

[0077] FIG. 1 illustrates a system 10 for purifying carbon dioxide (CO 2 ) source 80, and carbon dioxide (CO 2 ) source is e.g. CO 2 The line 52o may be fluidly connected to a sterilization loop, for example between the PD fluid pump 70 and the pressure sensor 72a. 2 Valve 54o is CO 2 As will be described in more detail below, the system 10 is adapted to reduce calcium carbonate (CaCO ) as the PD fluid is heated. 3 ), immediately prior to sterilization, a desired and effective amount of CO 2 Gas to CO 2 A sterile fluid, such as a PD fluid, is metered from the source 80. 2 The source 80 may be initially pressurized to 70 kPa (10 psig), for example, to provide sufficient pressure over multiple sterilization sequences according to the pressurization scheme described herein.

[0078] Figure 1 shows the gas or CO 2 Pressure regulator 74 and CO 2 The pressure sensor 76 detects the CO 2 CO along line 52o 2 It is further shown that the CO 2 The pressure regulator 74 regulates the CO 2 Allowing the source 80 to be pressurized to a higher level, resulting in CO 2 The source 80 lasts longer. The regulator 74 then 2The high incoming pressure from source 80 is gradually adjusted down to the desired output pressure. The desired operating pressure may be slightly above the pressure (or pressure rise) to be achieved, for example obtained from table 110 or table 120, as described below in connection with Figures 6 and 7, respectively. 2 The pressure sensor 76 is 2 CO remaining in source 80 2 The one-way or check valve 78 prevents unused or used PD fluid from entering the CO 2 A filter 54 may be provided and oriented to prevent entry into line 52o.

[0079] FIG. 1 still further illustrates that the APD cycle 20 of the system 10 of the present disclosure comprises a control unit 100 having one or more processors 102 and one or more memories 104 that control the pressure sensors 72a-72d and the CO, if provided, 2 The control unit 100 receives, stores, and processes signals or outputs from the pressure sensor 76, the temperature sensors 58a and 58b, the flow switch 68, and optionally 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 and used PD at safe patient and system pressure limits. The control unit 100 uses temperature feedback from the temperature sensor 58a to control the in-line PD fluid heater 56 to heat the fresh PD fluid, for example, to body temperature or 37° C. for treatment, and to 85° C. for sterilization. The control unit 100 uses flow switch feedback from the flow switch 68 to determine whether to power the PD fluid in-line heater 56. The control unit 100 determines how much CO2 is being pumped, as described herein. 2 CO 2 Feedback from pressure sensor 72a (and optionally pressure sensor 72b) is further used to determine whether or not pressure has been delivered to the sterilization loop via line 52o.

[0080] The control unit 100 illustrated in FIG. 1 also includes a video controller 106 in communication with a user interface 108, which may include a display screen operating with a touch screen and / or one or more electrochemical buttons, such as, for example, membrane switches. The user interface 108 may also include one or more speakers for outputting alarms, alerts, and / or voice guidance commands. The user interface 108 may be provided with the cycler 20, as illustrated in FIG. 1, and / or may be a remote user interface operating with the control unit 100. The control unit 100 may also include a transceiver (not shown) and a wired or wireless connection to a network, such as, for example, the Internet, for sending treatment data to, and receiving prescription orders from, a physician or clinician server in communication with a physician or clinician's computer.

[0081] Control unit 100 opens and closes PD fluid valves 54a-54h, 54o, 54s, 54u, and 54v in combination with operation of PD fluid pump 70 and in-line heater 56 to perform a priming sequence, a multi-patient fill sequence, a multi-patient drain sequence, and a disinfection sequence following a PD procedure. The disinfection sequence prepares APD cycler 20 for the next procedure. In an embodiment, remaining unused PD fluid is heated after the last patient drain and used as the disinfectant fluid for disinfection.

[0082] To form a sterilization loop 90 for a sterilization sequence, each reusable PD fluid supply line 24a-24d is connected to a respective sterile connector 30a-30d, and reusable patient line 26 is connected to reusable patient line connector 32, and in one embodiment drain line 36 is removed so that drain line connector 34 can close. As illustrated in FIGURE 1, sterilization loop 90 includes patient line connector 32 (with a U-turn or 180 degree turn), both lumens of reusable dual lumen patient line 26, used PD fluid patient tubing or line 52u, reusable sterile tubing or line 52d, reusable drain tubing or line 52h, vent tubing or line 52v, drain line connector 34, reusable PD fluid supply lines 24a-24d, bypass lines 52y, 52z, and reusable tubing or lines 52a-52c and 52f. Sterilization loop 90 also includes the interior of all flow components and fluid contact sensors located along the lines listed above.

[0083] The control unit 100 may sequence some of the valves along the sterilization loop 90 during sterilization. For example, the PD fluid supply valve 54a may be sequenced open and closed during sterilization to allow sterilizing fluid to flow through the supply valve 54a or be forced completely through the reusable PD fluid supply line 24a. The control unit 100 may cause the PD fluid pump 70 to run in forward and reverse states sequentially during sterilization so that sterilizing fluid may flow clockwise and counterclockwise through the sterilization loop 90. The control unit 100 also causes the in-line heater 56 to heat the sterilizing fluid, e.g., unused PD fluid, to a desired sterilization temperature, e.g., 70°C to 95°C.

[0084] The use of a PD fluid containing bicarbonate as a sterilizing fluid may be achieved by using calcium carbonate (CaCO ) in the sterilized flow path or flow components of the sterilization loop 90 of the PD machine or cycler 20. 3 ) from the source 80. 2) is provided immediately prior to pasteurization to prevent and / or remove calcium carbonate formation. 2 1 illustrates a simplified version of a disinfection loop 90 showing the key components of the input, CO from source 80. 2 The key components of the input are the PD fluid in-line heater 56, the first temperature sensor 58a, the PD fluid pump 70, the unused PD fluid patient pressure sensor 72a, the CO 2 Source 80, CO 2 Line 52o, CO 2 valve 54o, and control unit 100. However, it should be understood that the sequences described in relation to Figures 2-5 are equally applicable to the complete sterilization loop 90 of the PD machine or cycler 20 of system 10 of Figure 1.

[0085] Lookup tables based on bicarbonate level and / or sterilization temperature 6, the sequences of FIGS. 2-5 in an embodiment rely on a table 110 (or corresponding algorithm) stored in one or more memories 104 of the control unit 100, the table 110 including a CO2 concentration control algorithm based on at least one of the bicarbonate level in the PD sterilizing fluid or the sterilizing fluid temperature. 2 As shown in FIG. 6, the table 100 sets the pressure, or pressure rise, to be achieved due to the introduction of CO 2 Pressure rise or CO due to injection 2 The overall pressure to be achieved by the inputs (P11-P46) is set as a function of at least one of the solution bicarbonate composition (b1-b4) and the sterilizing fluid temperature setting (T1-T6). Accordingly, FIG. 6 illustrates the pressure (or pressure rise) to be achieved as a function of both bicarbonate level and sterilizing fluid temperature setting in a two-dimensional array. However, FIG. 6 could alternatively be used in reference to the pressure (or pressure rise) to be achieved as a function of only one of bicarbonate level or sterilizing fluid temperature.

[0086] Generally speaking, the more bicarbonate present in the unused PD fluid, the greater the CO 2A higher pressure is required in the table 110 due to the gas input. Furthermore, generally, the higher the sterilization PD fluid temperature, the higher the input CO 2 The higher pressure in table 110 is required due to the gas. In addition to table 110, CO 2 Source 80 is CO for many sterilization sequences 2 CO 2 CO 2 How much CO is needed to effectively block the formation of calcium carbonate precipitates while using gas? 2 To determine what gas pressure is required, experiments and / or calculations are performed varying bicarbonate levels for various sterilization temperatures.

[0087] The control unit 100 at the beginning of each sterilization sequence senses the bicarbonate level from the given PD fluid used for the just completed procedure. The control unit 100 also senses and sets the sterilization fluid temperature, which may be the same or different for the various sterilization sequences. The control unit 100 accesses the table 110 (or a corresponding algorithm) to find the operating pressure (or pressure rise) to achieve based on the known bicarbonate level and the known sterilization fluid temperature. It should be understood that the table 110 can alternatively compare the sterilization fluid temperature to the type of bicarbonate criteria of the PD fluid used, essentially similar to comparing the sterilization fluid temperature to the bicarbonate level. It should also be understood that PD fluids that do not contain bicarbonate do not have the precipitation problem described herein. Thus, when using a PD fluid that does not contain bicarbonate for sterilization, the control unit 100 does not access the table 110 and does not use the CO 2 Source 80 to CO 2 Do not inject gas.

[0088] Mole Fraction-Based Lookup Tables 7, the sequence of FIGS. 2-5 in an alternative embodiment relies on a table 120 (or a corresponding algorithm) stored in one or more memories 104 of the control unit 100, the table 120 including: 2 Table 120 of FIG. 7 shows the CO mole fraction depending on the type of sterilization fluid, e.g., the type of PD fluid, the PD fluid temperature (left column, °C), and the PD fluid pressure (top row, kPA). 2 where the mole fraction values ​​lie in a region corresponding to a given temperature and pressure. In an embodiment, a separate table (such as table 120) is stored and accessible by control unit 100 for each possible sterilizing or PD fluid, e.g., first for a 1.36% glucose PD fluid, second for a 2.27% glucose PD fluid, and third for a 3.86% glucose PD fluid.

[0089] In one example of using table 120 of FIG. 7, the following information is treated as known and may be stored in or part of the control unit 100: Sterilizing Loop 90 volume is 200ml. CO 2 Source 80 contains 18g of CO 2 Hold. CO 2 The molar mass is 44.01 g / mol. ·CaCO 3 The molar mass is 100.0869 g / mol. The sterilizing fluid molar mass is (H 2 Assuming the molar mass of O is 18.02 g / mol. ·Sterilizing fluid H 2 The O density is (H 2 O'H 2 O density is 0.96859 g / ml. Calcium (Ca) in sterilizing fluids 2+ The content is 1.25 mmol / L.

[0090] For each sterilization sequence, the following chemical reaction is used to remove calcium carbonate, where H 2 CO 3 is carbonic acid and HCO 3 is bicarbonate and H 2 O is obtained from the PD fluid used for sterilization. [ka]

[0091] The goal of CO2 injection is to produce dissolved CO 2 The goal is to increase the pressure measured by pressure sensor 72a so that CO is maintained at the predefined amount calculated above as 0.5 mmol during the heat sterilization sequence. 2 The assumption is made that the source of PD fluid used for sterilization (e.g., a bag of such fluid) is in equilibrium with the surrounding environment in terms of temperature and pressure, so that the initial partial pressure of CO may be assumed to be approximately 0.04 kPa (the partial pressure of CO in the environment). Using table 120 in FIG. 7, an extrapolation from a 0.031 mole fraction valve at 5 kPa and 25° C. yields the initial partial pressure of CO at normal environmental conditions. 2 ((0.04 kPa / 5 kPa) is approximately 1 / 10 of 0.031, and 1 / 10 of 0.031 is equal to 0.00031 mole fraction).

[0092] In the example, it is also assumed (and would be known in commercial implementations) that the volume of sterilizing fluid or PD fluid circulated in the sterilizing loop 90 is 200 milliliters ("ml"). Finding the density of the PD sterilizing fluid (using the density of water in the example), 200 ml of PD fluid is equivalent to 193.72 grams or 10.75 moles of fluid in the sterilizing loop 90. At normal environmental conditions (5 kPa and 25°C), 10.75 moles x 0.00031 mole fraction equals 0.0033 mmol of CO 2 0.0033 mmol of CO as estimated from Table 120 in FIG. 7 for 0.04 kPa at a typical sterilization temperature of 85° C.2 is 0.0012 mmol CO at 85°C. 2 (0.00011 mole fraction x 10.75 moles). The decrease is 0.5012 (0.0012 + 0.5) mmol of CO 2 needs to be injected into the heated PD fluid. Next, 0.5012(0.0012+0.5) mmol of CO 2 results in a required mole fraction of 0.5012 / 10.75=0.0466, which in turn results in a partial pressure rise of approximately 21 kPa (3 psig) at 85° C., according to table 120 of FIG.

[0093] 7, which is programmed into the control unit 100, and the above known quantities based on certain assumptions, the control unit 100 can calculate, for a given PD fluid to be used as a sterilizing fluid, and for a given sterilizing temperature (each of which may be programmed into the control unit 100 at the time of treatment or may be known from the patient's prescription), the pressure that the sterilizing PD fluid will be at when it is pumping CO from the source 80. 2 The pressure that needs to be increased by the CO 2 It is set by pressure regulator 74.

[0094] CO 2 Input Step 2 illustrates the first step where the PD procedure is completed and it is time for the control unit 100 to perform sterilization. Prior to initiating the sterilization sequence, the control unit 100 in one embodiment 2 With valve 54o closed (not blacked out), PD fluid pump 70 not activated, and in-line heater 56 not energized, the control unit 100 finds the pressure (or pressure rise) to be achieved from table 110 of FIG. 6 based on the known bicarbonate level and / or sterilization temperature. 2With valve 54o closed, PD fluid pump 70 not activated, and in-line heater 56 not energized, the initial CO 2 To obtain the mole fraction value, an initial pressure measurement is made by pressure sensor 72a and an initial temperature measurement is made by temperature sensor 58a. An optional PH sensor or CO 2 The sensor detects the initial CO 2 Table 120 of FIG. 7 for sterilizing fluids would satisfy and eliminate the need for extra sensors, although they could alternatively or additionally be provided and used to determine the mole fractions.

[0095] FIG. 3 illustrates a second step in which the control unit 100 controls the CO 2 Open valve 54o (black painted valve) and CO 2 The control unit 100 allows CO to be injected into the PD fluid in the sterilization loop 90. 2 Pulse or CO 2 6 or 7. In either case, the control unit 100 monitors the output of the pressure sensor 72a and determines when the pressure achieves the pressure (or pressure rise (e.g., about 3 psig (21 kPa) at 85° C.)) required from table 110 of FIG. 6 or table 120 of FIG. 7) that is required. 2 Stop the injection of

[0096] 4 illustrates a third step in which the control unit 100 causes the in-line heater 56 to be energized and the PD fluid pump 70 to circulate the heated sterilizing fluid (PD fluid) at the elevated pressure obtained in FIG. 3 through the sterilizing loop 90 in any of the alternative modes previously described. The heated sterilizing fluid circulation occurs for a specified period of time. During this period, a specified amount of CO at the elevated pressure is pumped through the sterilizing loop 90. 2 The presence of calcium carbonate (CaCO) follows the chemical reaction shown above. 3) is prevented or removed. 2 While valve 54o is shown as closed (not shaded), in an alternative embodiment, control unit 10 may direct CO 2 into sterilization loop 90 during part or all of the heat sterilization. 2 To allow gas to be injected, CO 2 It should be understood that this may result in valve 54o being opened.

[0097] 5 illustrates a fourth, and possibly optional, step in which the control unit 100 deenergizes the in-line heater 56 but continues to enable the fluid pump 70 to circulate cooled PD fluid. During the cooling period, the control unit 100 monitors the output of the pressure sensor 72a to see if the output returns to the pressure level prior to heating in FIG. 4. If any CO 2 The leak occurs and the pressure drops to the end of Figure 3. 2 If the post-injection pressure falls below this level, the control unit 100 may, for example, inject additional CO 2 to regain the required pressure rise above the initial start-up pressure (e.g., about 21 kPa (3 psig)). 2 to allow CO to be injected. 2 Valve 54o can be opened (blackened valve). Ammonia and / or CO 2 A sensor, if provided, may be used here in addition or instead. Note that the cooled PD fluid contains a higher mole fraction of CO 2 As a result, CO 2 The pressure does not need to be increased to the previous level (eg 21 kPa).

[0098] In one embodiment, the control unit 100 is configured to detect whether the PD fluid patient tubing or line 52f is CO 2 Any pressure remaining in the source 80 2 Valves 54e, 54f, 54g, 54h, and 54u are closed to allow the CO 2The valve 54o is opened. The first patient pressure sensor 72a now detects CO 2 The pressure remaining in the sensor 80 is read and a corresponding signal is sent to the control unit 100. In an alternative embodiment shown in FIG. 2 The pressure sensor 76 is 2 1. The pressure regulator 74 is provided upstream of the pressure regulator 74 so that it can read the pressure remaining in the source 80 and send a corresponding signal to the control unit 100. In either situation, the control unit 100 in the embodiment 2 CO so that sauce 80 can be ordered and delivered to the patient. 2 The user interface 108 is configured to send a message to a central location when it determines that the pressure level in the CO source 80 is getting low. 2 An audio, visual, or audiovisual message may also be provided to the patient that the source 80 is getting low but a new supply is arriving. 2 When receiving the source 80, the user interface 108 selects an existing CO 2 Source 80 New CO 2 Audio, visual, or audiovisual instructions on how to replace source 80 may also be provided to the patient.

[0099] It should be understood that various changes and modifications of the presently preferred embodiments described herein will be readily apparent to those skilled in the art. Accordingly, it is intended that such changes and modifications are covered by the appended claims. For example, while Figures 2-5 illustrate readings obtained from a single pressure sensor and a temperature sensor, the control unit 100 may instead analyze pressure and temperature outputs from multiple pressure and temperature sensors located at different locations along the sterilization loop 90. As mentioned herein, the pressures listed in tables 110 and 120 of Figures 6 and 7, respectively, may be absolute pressure values ​​or pressure rise or pressure delta values.

Claims

1. 1. A peritoneal dialysis ("PD") system comprising: A PD fluid pump; a sterilization loop comprising the PD fluid pump, the sterilization loop comprising a PD fluid used to sterilize the sterilization loop; Carbon Dioxide (CO ２ ), a source of calcium carbonate (CaCO ) during the sterilization sequence. ３ ) into the sterilization loop to inhibit and / or eliminate the production of CO ２ carbon dioxide (CO ２ ), with source Including, P.D. system.

2. The sterilization loop and the CO ２ CO located between the source ２ 10. The PD system of claim 1, further comprising a valve. ２ A valve is provided to the sterilization loop. ２ The PD system is opened to allow for the

3. In order to inhibit and / or remove the formation of said calcium carbonate during the sterilization sequence, ２ to enable the CO ２ The PD system of claim 2 comprising a control unit configured to cause the valve to open.

4. 4. The PD system of claim 3, further comprising at least one pressure sensor having an output to the control unit, the control unit being configured to monitor an output of the at least one pressure sensor to detect the desired pressure or pressure increase.

5. The PD system of claim 3 , wherein the control unit is configured to use a look-up table to determine the desired pressure or pressure increase.

6. 6. The PD system of claim 5, wherein the control unit stores a sterilization temperature, the PD fluid is heated to the sterilization temperature for the sterilization sequence, and the desired pressure or pressure rise in the look-up table corresponds to the sterilization temperature.

7. 7. The PD system of claim 6, further comprising at least one temperature sensor having an output to the control unit, the control unit being configured to monitor the at least one temperature sensor output to detect the sterilization temperature.

8. The PD system of claim 5 , wherein the look-up table is specific to the type of PD fluid used for sterilization.

9. 6. The PD system of claim 5, wherein the control unit senses a bicarbonate level of the PD fluid used for sterilization, and the desired pressure or pressure increase in the lookup table corresponds to the bicarbonate level.

10. The control unit is configured to supply CO ２ and obtaining initial pressure and temperature readings prior to supplying CO 2 contained in the sterilization loop, the control unit further comprising: ２ The PD system of claim 5 configured to determine an initial amount of

11. The PD system of claim 3 , wherein the control unit is configured to use an algorithm to determine the desired pressure or pressure increase.

12. The control unit may further comprise a control unit configured to control the CO ２ to pressurize the PD fluid to the desired pressure or pressure increase. ２ The PD system of claim 3 configured to cause a valve to open.

13. The control unit controls the PD fluid pump to operate during the disinfection sequence while simultaneously controlling the CO ２ to pressurize the PD fluid to the desired pressure or pressure increase. ２ The PD system of claim 3 configured to cause a valve to open.

14. 4. The PD system of claim 3, further comprising a PD fluid heater, the control unit controlling the CO ２ to pressurize the PD fluid to the desired pressure or pressure increase. ２ The PD system is configured to open the valve.

15. 4. The PD system of claim 3, further comprising a PD fluid heater, the control unit configured to control the CO ２ to pressurize the PD fluid to the desired pressure or pressure increase. ２ The PD system is configured to open the valve.

16. The control unit may further comprise a step of: ２ to pressurize the PD fluid. ２ The PD system of claim 3 configured to cause a valve to open.

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