PERITONEAL DIALYSIS CYCLER HAVING DISINFECTION

Abstract

A peritoneal dialysis (“PD”) system includes a first volumetric balancing chamber including a first fixed volume chamber and a first diaphragm positioned and arranged to extend back and forth within the first fixed volume chamber, the first diaphragm separating a fresh PD fluid side from a used PD fluid side of the first volumetric balancing chamber; a second volumetric balancing chamber including a second fixed volume chamber and a second diaphragm positioned and arranged to extend back and forth within the second fixed volume chamber, the second diaphragm separating a fresh PD fluid side from a used PD fluid side of the second volumetric balancing chamber; and a PD fluid pump positioned and arranged to pump used PD fluid back and forth between the used PD fluid sides of the first and second volumetric balancing chamber.

Claims

1. A peritoneal dialysis (“PD”) system comprising: a first volumetric balancing chamber including a first fixed volume chamber and a first diaphragm positioned and arranged to extend back and forth within the first fixed volume chamber, the first diaphragm separating a fresh PD fluid side from a used PD fluid side of the first volumetric balancing chamber; a second volumetric balancing chamber including a second fixed volume chamber and a second diaphragm positioned and arranged to extend back and forth within the second fixed volume chamber, the second diaphragm separating a fresh PD fluid side from a used PD fluid side of the second volumetric balancing chamber; and a PD fluid pump positioned and arranged to pump used PD fluid back and forth between the used PD fluid sides of the first and second volumetric balancing chambers.

2. The PD system of claim 1, which includes at least one valve in fluid communication with the fresh PD fluid side of one of the first or second volumetric balancing chambers, and wherein fresh PD fluid is discharged from the fresh PD fluid side through the at least one valve when the PD fluid pump pumps used PD fluid to the used PD fluid side of the first or second volumetric balancing chamber.

3. The PD system of claim 2, which includes a control unit configured to operate the PD fluid pump, the control unit configured to determine an amount of fresh PD fluid discharged from the fresh PD fluid side of the first or second volumetric balancing chamber via (i) monitoring a pumping output of the PD fluid pump and/or (ii) using a known volume of the first or second fixed volume chamber.

4. The PD system of claim 1, which includes at least one valve in fluid communication with the fresh PD fluid side of the first or second volumetric balancing chamber, and wherein fresh PD fluid is drawn into the fresh PD fluid side through the at least one valve when the PD fluid pump pumps used PD fluid from the used PD fluid side of the first or second volumetric balancing chamber.

5. The PD system of claim 1, which is configured during a patient drain such that the PD fluid pump pumps used PD fluid through a patient line, through one of the first or second volumetric balancing chambers, and through a drain line.

6. The PD system of claim 5, wherein the PD fluid pump pumps used PD fluid through a return lumen of the patient line, and wherein the patient line further includes an output lumen for delivering fresh PD fluid to a patient.

7. The PD system of claim 5, which includes a control unit configured to operate the PD fluid pump during the patient drain, the control unit configured to determine an amount of used PD fluid removed during the patient drain via monitoring at least one pumping output of the PD fluid pump.

8. The PD system of claim 1, which includes a first heater in fluid communication with the fresh PD fluid sides of the first and second volumetric balancing chambers, and a second heater in fluid communication with the used PD fluid sides of the first and second volumetric balancing chambers, wherein the first heater is used in a sterilization sequence and the second heater is used in a disinfection sequence.

9. The PD system of claim 8, wherein the first heater is further used to heat fresh PD fluid for treatment.

10. The PD system of claim 8, wherein the first heater heats fresh PD fluid to at least 120° C. for the sterilization sequence, and the second heater heats fresh or used PD fluid to at least 65° C. for the disinfection sequence.

11. The PD system of claim 1, which includes a sterilization loop including the fresh PD fluid sides of the first and second volumetric balancing chambers and at least one of (i) at least one reusable solution line or (ii) at least one sealed cover that closes over at least one patient line port and/or drain line port.

12. The PD system of claim 1, which includes a disinfection loop including the used PD fluid sides of the first and second volumetric balancing chambers and at least one sealed cover that closes over at least one patient line port and/or drain line port.

13. The PD system of claim 1, which is configured to run a patient drain in which (i) the first and second volumetric balancing chambers are bypassed and the accuracy of PD fluid pump is relied upon or (ii) the first and second volumetric balancing chambers are operated.

14. A peritoneal dialysis (“PD”) system comprising: a first volumetric balancing chamber including a first fixed volume chamber and a first diaphragm positioned and arranged to extend back and forth within the first fixed volume chamber, the first diaphragm separating a fresh PD fluid side from a used PD fluid side of the first volumetric balancing chamber; a second volumetric balancing chamber including a second fixed volume chamber and a second diaphragm positioned and arranged to extend back and forth within the second fixed volume chamber, the second diaphragm separating a fresh PD fluid side from a used PD fluid side of the second volumetric balancing chamber; and a first heater in fluid communication with the fresh PD fluid sides of the first and second volumetric balancing chambers, and a second heater in fluid communication with the used PD fluid sides of the first and second volumetric balancing chambers, wherein the first heater is used in a sterilization sequence and the second heater is used in a disinfection sequence.

15. The PD system of claim 14, wherein the first heater is further used to heat fresh PD fluid for treatment.

16. The PD system of claim 14, wherein the first heater heats fresh PD fluid to at least 120° C. for the sterilization sequence, and the second heater heats fresh or used PD fluid to at least 65° C. for the disinfection sequence.

17. The PD system of claim 14, which includes a sterilization loop including the fresh PD fluid sides of the first and second volumetric balancing chambers and at least one of (i) at least one reusable solution line or (ii) at least one sealed cover that closes over at least one patient line port and/or drain line port.

18. The PD system of claim 14, which includes a disinfection loop including the used PD fluid sides of the first and second volumetric balancing chambers and at least one sealed cover that closes over at least one patient line port and/or drain line port.

19. A peritoneal dialysis (“PD”) system comprising: a sterilization loop including a fresh PD fluid side of a PD machine; a disinfection loop including a used PD fluid side of the PD fluid machine; and a control unit configured to run a sterilization sequence in the sterilization loop and a disinfection sequence in the disinfection loop.

20. The PD system of claim 19, wherein the sterilization loop includes a fresh PD fluid side of at least one volumetric balancing chamber, and wherein the disinfection loop includes a used PD fluid side of the at least one volumetric balancing chamber.

21. The PD system of claim 19, wherein the disinfection loop includes at least one reusable solution line, and wherein the disinfection loop includes at least one sealed cover that closes over at least one patient line port and/or drain line port.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0056] FIG. 1 is a schematic view of one embodiment of a peritoneal dialysis (“PD”) machine and associated system having a single pump located on a used PD fluid side of the machine.

[0057] FIG. 2 is a schematic view of the embodiment of the PD machine and associated system of FIG. 1 in a sterilization/disinfection mode performing a “germ deactivation”.

[0058] FIG. 3 is a schematic view of another embodiment of a peritoneal dialysis (“PD”) machine and associated system having a single pump located on a used PD fluid side of the machine.

[0059] FIG. 4 is a schematic view of a third embodiment of a peritoneal dialysis (“PD”) machine and associated system having a single pump located on a used PD fluid side of the machine.

[0060] FIG. 5 is a schematic view of a third embodiment of a peritoneal dialysis (“PD”) machine and associated system having a single pump located on a used PD fluid side of the machine.

DETAILED DESCRIPTION

[0061] Referring now to the drawings and in particular to FIG. 1, a peritoneal dialysis (“PD”) system 10a and associated methodology of the present disclosure includes a PD machine 20a. System 10a and PD machine 20a (as do other systems and machines or cyclers described herein) attempt to eliminate disposable items as much as possible and instead provide a majority of its fluid carrying portions as reusable components, which are disinfected after treatment. PD machine 20a includes a housing 22 that holds the reusable flow components and tubes or lines described herein. Any of the housing and reusable flow components and lines discussed herein may be made of metal, e.g., stainless steel, steel (for non-fluid contacting components) or aluminum (for non-fluid contacting components), or plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), polyetereterketon (“PEEK”), polyurethane (“PU”) or polycarbonate (“PC”).

[0062] PD machine 20a includes a PD fluid pump 24, such as an electrically operated piston, membrane or gear pump, which may be inherently accurate. PD machine 20a in the illustrated embodiment includes two heaters 26a and 26b, such as an inline heaters. Heater 26a, which is the treatment fluid heater, is capable of heating PD fluid from room temperature or colder to body temperature, e.g., 37° C., at a flowrate of at least 300 milliliters (“ml”)/minute (typical PD fill and drain flowrates are 200 to 300 ml/min). Heaters 26a and 26b are both used for “germ deactivation” (a term used herein include either sterilization or disinfection or both) at the end of treatment. Heater 26a is used for sterilization, while heater 26b is used for disinfection. Sterilization requires higher temperatures as discussed herein. Heaters 26a and 26b may both be capable of obtaining sterilization temperatures and may be the same or different heaters with the same or different capabilities.

[0063] PD machine 20a includes a plurality of valves 28a to 28o, which may be electrically actuated solenoid valves having a reusable valve body that occludes (e.g., when unpowered) or allows (e.g., when powered) dialysis fluid to flow through the body. Valves 28a to 28d are solution or supply valves. Valves 28e to 28i are fresh dialysis fluid inlet/outlet valves. Valves 28j to 28m are used dialysis fluid inlet/outlet valves. Valves 28n and 28o are toggling valves that allow used dialysis fluid to be pumped back and forth between volumetric balancing chambers 40a and 40b. Valves 28n and 28o may also be used when system 10a detects air in a pump chamber. Toggling valves 28n and 28o, like valve 28h, are three-way valves that switch flow path positions or orientations upon electrical actuation.

[0064] Although not illustrated in system 10a of FIG. 1, one or more airtrap may be provided, which operates with one or more level sensor located adjacent the airtrap, so that a desired level or range of levels of fresh or used PD fluid may be maintained in the airtrap. The level sensors may be ultrasonic, capacitance, inductive or optical sensors capable of discerning between fresh or used PD fluid versus air inside the airtrap.

[0065] PD machine 20a further includes temperature sensors 36a and 36b located adjacent to inline heaters 26a and 26b, respectively. In the illustrated embodiment, temperature sensors 36a and 36b are located downstream from heaters 26a and 26b. Third and fourth temperature sensors may also be located upstream from heaters 26a and 26b. The output from temperature sensors 36a and 36b are used as feedback to control how much power is supplied to inlet heaters 26a and 26b when fresh or used PD fluid is flowing through same.

[0066] Dialysis machine 20a also includes a plurality of pressure sensors 34a to 34c. The outputs from pressure sensors 34a to 34c are used to make sure that the pumping of fresh PD fluid to the patient is performed within a safe positive pressure limit, e.g., one to five psig (e.g., two psig (14 kPa), and that the pumping of used PD fluid from the patient is performed within a safe negative pressure limit, e.g., −1.0 psig to −3.0 psig (e.g., −1.3 psig (−9 kPa)). Pressure sensors 34a to 34c are each illustrated as being on the used PD fluid side of PD machine 20a, which is advantageous because they maximally see the disinfection temperature after treatment (as opposed to a higher sterilization temperature). The outputs from pressure sensors 34a and 34b associated with volumetric balancing chambers 40a and 40b, respectively, are nevertheless able to be used to control and monitor positive fresh PD fluid pumping pressures because the used PD fluid is used to drive the fresh PD fluid. The pressure of the used PD driving fluid is translated to and is thus the same as the driven fresh PD fluid.

[0067] PD machine 20a further includes at least one conductivity sensor 38, which may be temperature compensated. In FIG. 1, conductivity sensor 38 is shown located to sense used PD fluid, the output of which may be used to evaluate the effectiveness of the PD treatment and/or to look for disease, such as peritonitis. Conductivity sensor 38 may also be used, e.g., in a priming scenario, to measure the conductivity of fresh PD fluid to confirm that the fluid meets a prescribed PD fluid. Locating conductivity sensor 38 in the used PD fluid side of PD machine 20a is also advantageous in that the conductivity sensor only needs to see the disinfection temperature after treatment.

[0068] PD machine 20a of system 10a includes a control unit 50 having one or more processor 52, one or more memory 54 and a video controller 56, which controls a display device 58 associated with a user interface 60 of the machine. Control unit 50 controls each of PD fluid pump 24, inline heaters 26a, 26b, and valves 28a to 28o according to the flow sequences discussed herein. Control unit 50 also receives outputs from level sensors (discussed below), pressure sensors 34a to 34c, temperature sensors 36a, 36b and one or more conductivity sensor 38, and uses those outputs for feedback purposes discussed herein and also for any readout(s) desired at display device 58.

[0069] User interface 60 may include a touchscreen overlay operable with display device 58 and/or one or more electromechanical button, such as a membrane switch for inputting user commands. User interface 60 displays information to the user at display device 58 and may also include one or more speaker for outputting alarms, alerts and/or voice guidance commands. User interface 60 may be provided with PD machine 20a as illustrated in FIG. 1 and/or be a remote user interface operating with control unit 50. Control unit 50 may also include a transceiver (not illustrated) and a wired or wireless connection to a network, e.g., the internet, for sending treatment data to and receiving prescription instructions from a doctor's or clinician's server interfacing with a doctor's or clinician's computer.

[0070] Volumetric balancing chambers 40a and 40b are passive components in that they do not receive electrical inputs and are not under direct control by control unit 50. Volumetric balancing chambers 40a and 40b are instead operated via fluid pressure as directed by their associated valves. Volumetric balancing chambers 40a and 40b each include a fixed volume chamber 42, which may be made of any medically safe material discussed herein. Fixed volume chambers 42 include a flexible diaphragm or membrane 44, which flexes back and forth to receive a volume of used PD and dispel a like volume of fresh PD fluid. Flexible diaphragms or membranes 44 may be made of a durable and medically safe rubber, e.g., silicone, which does not permanently deform over multiple uses.

[0071] Housing 22 of PD machine 20a includes multiple features provided to aid the “germ deactivation” (sterilization and disinfection) performed after treatment. Housing 22 for example includes spring-loaded doors 30a to 30c, which cover reusable solution lines 102a to 102c, respectively, after treatment when reusable solution lines 102a to 102c are disconnected from disposable pigtails 104a to 104c extending from PD fluid containers 106a to 106c. As illustrated in FIG. 2, reusable solution lines 102a to 102c when disconnected are plugged into sterilization ports 32a to 32c provided in housing 22.

[0072] Housing 22 also includes an output port 46a that receives an output lumen 108a of a patient line 108. Housing 22 further includes a return port 46b that receives a return lumen 108b of patient line 108. Housing 22 additionally includes a drain port 46c that receives a drain line 112. Each of ports 46a to 46c is covered with a sealed cover 48, e.g., which spring-closes over ports 46a to 46c, when patient line 108 and drain line 112 are removed. Sealed covers 48 direct the sterilization fluid (port 46a) and the disinfection fluid (ports 46b and 46c) back into PD machine 20a and thereby help form the sterilization and disinfection loops, respectively.

[0073] In the illustrated embodiments herein, output lumen 108a is provided with a sterile, sterilizing grade filter 110, which provides a final level of sterilization to the fresh PD fluid prior to being delivered to the patient via patient line 108. Pore sizes for sterile, sterilizing grade filter 110 may, for example, be 0.1 to 0.2 micron. Suitable sterile, sterilizing grade filters may, for example, be Pall IV-5 or GVS Speedflow filters. It is envisioned that sterilizing grade filter 110 is eventually not needed or provided assuming that the fresh PD fluid side of system 10a has been sterilized properly. It is contemplated to perhaps provide sterilizing grade filter 110 until it is proven that proper sterilization is achievable and that the filter is not needed.

[0074] In FIGS. 1 to 5, valves that are darkened are open, while valves that are unshaded are closed. FIG. 1 illustrates a first PD machine 20a, which operates as part of system 10a, which also includes all disposable items, such as PD fluid containers 106a to 106c and their pigtails 104a to 104c, patient line 108 (including sterile, sterilizing grade filter 110 if provided) and drain line 112. In the systems of any of FIGS. 1 to 5, the patient may begin the treatment full of effluent from a previous treatment or be empty. Control unit 50 of PD machine 20a (and any of the PD machines discussed herein) may be programmed to start treatment by applying negative pressure to the patient. If the patient does not have effluent PD fluid to give, the patient is likely empty although patient line 108 could instead be kinked, which may be discovered or fixed by alarming or trying to clear the occlusion, respectively. Machine 20a may also be configured to check if the patient's fluid status is different than expected, e.g., perhaps the patient skipped a prescribed day fill. Control unit 50 may also be configured to initially try to push a small amount of PD fluid towards the patient to determine if a kink or other line occlusion exists. If a kink does not exist, then control unit 50 continues to the next programmed action. If a kink does exist, control unit 50 causes user interface 60 to issue an alarm.

[0075] If the patient is full of effluent at the beginning of treatment, PD machine 20a (and any of the PD machines discussed herein) senses same by causing PD fluid pump 24 to attempt to pull effluent from the patient through patient line 108 and return lumen 108b. Not sensing a resistance to the negative pressure, control unit 50 determines that the patient is full of effluent and continues with the initial drain. Control unit 50 here causes PD fluid pump 24 to continue pulling effluent from the patient through patient line 108 and return lumen 108b, through three-way valve 28n (for example), and for PD fluid pump 24 to push the effluent through three-way valve 28o, the effluent or used PD fluid side of volumetric balancing chamber 40b, and through valves 28k and 28l, drain port 46c, drain line 112 to a drain container or house drain (e.g., toilet or bathtub). In the above patient draining embodiment, PD fluid pump 24 needs to be an accurate pump, such as a piston pump, since volumetric balancing chambers 40a and 40b are bypassed.

[0076] In an embodiment, the accuracy of PD fluid pump 24 is relied on to know how much effluent has been removed during the patient drains (initial and subsequent drains). PD fluid pump 24 may for example be a piston pump that pumps a precise amount of effluent per every piston stroke. Control unit 50 accumulates the number of piston strokes over the course of multiple patient drains. A patient drain may end upon at least a minimum prescribed amount of effluent being removed from the patient. A patient drain may end alternatively upon control unit 50 receiving a characteristic pressure signal indicating that the patient is empty or virtually empty. The pressure signal to the control unit 50 may be from any one or more of pressure sensors 34a to 34c.

[0077] An alternative draining flow path through at least one volumetric balancing chamber may be used instead. In one example, used PD fluid is pumped into volumetric balancing chamber 40b. Control unit causes valves 28i, 28g, 28j and 28l to be open, while valve 28k is closed. Used PD fluid may also be drained from volumetric balancing chamber 40a to drain line 112. In the next half-cycle, volumetric balancing chamber 40b is initially full of patient effluent, while volumetric balancing chamber 40a is initially empty. Here, control unit 50 causes PD fluid to pump drained effluent towards volumetric balancing chamber 40a, which in turn pushes fresh fluid over to volumetric balancing chamber 40b, causing drained effluent to be pushed to drain line 112 via the now open valve 28k (valve 28j is here closed). In this alternative patient draining embodiment, PD fluid pump 24 may be a less accurate pump because volumetric balancing chambers 40a and 40b are used and provide volumetric accuracy. It is worth noting however that using a single accurate pump, such as a piston pump, is also advantageous because whatever error is present tends to cancel out when determining a patient's ultrafiltration (“UF”) volume, which is a difference between one or more drain volume and one or more fill volume. If a presumption that the accurate pump tends to error in the same manner for a patient drain as a patient fill is correct, then the two errors, albeit small due to the accuracy of the pump, will cancel and yield an even more accurate UF removed volume. And it is more important for a PD treatment that UF volume is determined accurately. Volumetric balancing chambers 40a and 40b may be used as a supervisory or primary way of determining volume pumped, with the accurate pump volume used as a check.

[0078] If the patient is instead empty at the beginning of treatment, then control unit 50 transitions to an initial fill. Because there is no fluid on the used PD or effluent sides of volumetric balancing chambers 40a and 40b at this time, control unit 50 instead causes PD fluid pump 24 to pump air initially to place negative pressure on flexible diaphragms 44 to pull fresh PD fluid from PD fluid container 106a, for example, through valves 28g and 28i, and into the fresh PD fluid sides of volumetric balancing chambers 40a and 40b, respectively. Control unit 50 then causes PD fluid pump 24 to pump air in the opposite direction to place positive air pressure on the flexible diaphragms 44 of volumetric balancing chambers 40a and 40b to discharge fresh PD fluid therefrom. The fresh PD fluid travels through valves 28g and 28i and valves 28f and 28e into output lumen 108a and patient line 108. The above process (drawing fresh PD fluid into volumetric balancing chambers 40a and 40b and discharging same from the balancing chambers by pumping air at PD fluid pump 24) is repeated until enough fresh PD fluid resides within patient line 108 to fill the used PD fluid or effluent side of volumetric balancing chambers 40a and 40b, or at least enough of same so that PD fluid pump 24 can pump fresh PD fluid back and forth between the volumetric balancing chambers.

[0079] Control unit 50 then performs the initial patient fill using the above process (drawing fresh PD fluid into volumetric balancing chambers 40a and 40b and discharging same from the balancing chambers) but does so now by pumping fresh PD fluid back and forth between the effluent sides of volumetric balancing chambers 40a and 40b instead of air. Control unit 50 performs the initial patient fill (and all subsequent patient fills according to above fill and discharge) by metering fresh, heated (at heater 26a under control of control unit 50) PD fluid to the patient via patient line 108 until a prescribed amount of fresh PD fluid is delivered. It should be appreciated that subsequent patient fills (any after the initial patient fill) occur after a patient drain in which the used PD fluid or effluent side of volumetric balancing chambers 40a and 40b is primed with used PD fluid or patient effluent from the prior drain.

[0080] In an alternative embodiment, control unit 50 causes system 10a to be primed fully (including fresh and used PD fluid sides of volumetric balancing chambers 40a and 40b) prior to the patient connecting to PD machine 20a. Here, fresh PD fluid is pumped through both sides of volumetric balancing chambers 40a and 40b and eventually to drain via drain line 112.

[0081] For patient filling in any of the systems and PD cyclers discussed herein, volumetric accuracy may be monitored and controlled in one or more way. One way is discussed above for patient draining, which is for control unit 50 to count accurate pump fill strokes made by PD fluid pump 24. That is, the amount of fluid pumped back and forth between volumetric balancing chambers 40a and 40b via three-way valves 28n and 28o should equal the amount of fresh, heated PD fluid discharged from volumetric balancing chambers 40a and 40b to the patient. The other way is for control unit 50 to count and accumulate the number of discharge strokes made by each of volumetric balancing chambers 40a and 40b. The volumes of the fixed volume chambers 42 of volumetric balancing chambers 40a and 40b are known so that each time fresh PD fluid is discharged from the chambers, the incremental volume may be accumulated by control unit 50. Pressure sensors 34a and 34b operating with volumetric balancing chambers 40a and 40b, respectively, are well-positioned to detect when flexible diaphragms 44 dead end against a wall of fixed volume chambers 42, confirming that a full stroke of fresh PD fluid has been discharged from the fixed volume chambers. Control unit 50 may employ both methods for monitoring filling accuracy for comparison and/or for calibrating PD fluid pump 24 for the next patient drain where the accuracy of PD fluid pump 24 is needed.

[0082] Referring now to FIG. 2, an example “germ deactivation” (sterilization/disinfection) sequence for PD machine 20a of system 10a is illustrated. The teachings of the “germ deactivation” sequence are applicable to any of the PD machines and associated systems discussed herein. Here, at the end of treatment, the patient or caregiver removes PD fluid containers 106a to 106c. Spring-loaded doors 30a to 30c automatically close over reusable solution lines 102a to 102c, respectively, which are sealingly plugged into sterilization ports 32a to 32c. A sterilization loop is thereby formed, which includes reusable solution lines 102a to 102c, the reusable lines within PD machine 20a that lead to the fresh PD fluid sides of volumetric balancing chambers 40a and 40b, the fresh PD fluid sides themselves and output port 46a.

[0083] At the end of treatment, the patient or caregiver also removes patient line 108 (including output lumen 108a and return lumen 108b) and drain line 112 from ports 46a to 46c, respectively. Sealed cover 48 covers, e.g., spring-closes over exposed output port 46a to seal the port and force sterilization fluid back into the sterilization loop. Sealed covers 48 also, e.g., spring-close over exposed ports 46b to 46c to seal the ports and force disinfection fluid back into a disinfection loop that also includes the used PD fluid or effluent side of PD machine 20a up to and including the used sides of volumetric balancing chambers 40a and 40b. The disinfection loop at the end of treatment is full of used PD fluid or patient effluent, which may be used for the disinfection sequence if desired. If fresh PD fluid is desired for disinfection instead, then control unit 50 causes PD fluid pump 24 to pump a disinfection loop volume's worth of fresh PD fluid into patient line 108 prior to its removal. Control unit 50 also causes PD fluid pump 24 to pull the fresh PD fluid into the disinfection loop from patient line 108 and push the used PD fluid from the disinfection loop to a drain container or house drain via drain line 112 prior to its removal. The disinfection loop or used PD fluid side of volumetric balancing chambers 40a and 40b is now primed with leftover fresh PD fluid for disinfection. The sterilization loop or fresh PD fluid side of volumetric balancing chambers 40a and 40b is also now primed with leftover fresh PD fluid for sterilization.

[0084] In an embodiment, it does not matter which “germ deactivation” portion takes place first, sterilization or disinfection. The two sequences may overlap, however the sterilization sequence needs to sterilize the fresh PD fluid sides of volumetric balancing chambers 40a and 40b, while the disinfection sequence needs to disinfect the used PD fluid sides of the volumetric balancing chambers. It may not be possible to sterilize and disinfect volumetric balancing chambers 40a and 40b at the same time. Moreover, PD fluid pump 24 is needed in both sterilization and disinfection sequences and may not be able to perform double duties simultaneously.

[0085] For sterilization, it is contemplated that control unit 50 receives feedback from temperature sensor 36a to cause sterilization/treatment heater 26a to heat the leftover fresh PD fluid in the sterilization loop to a desired sterilization temperature of, for example, 120° C. or higher. PD fluid pump 24 pumps leftover PD fluid back and forth between the used PD fluid sides of volumetric balancing chambers 40a and 40b, causing heated leftover PD fluid in the sterilization loop to be circulated back and forth to contact and sterilize all areas of the sterilization loop. The areas of the sterilization loop contacted with superheated PD fluid include reusable solution lines 102a to 102c, sterilization ports 32a to 32c, valves 28a to 28i, associated lines, the fresh PD fluid sides of volumetric balancing chambers 40a and 40b, and output port 46a. Any one or more or all of valves 28a to 28i may be toggled open and closed during the sterilization sequence to aid the sterilization. Control unit 50 concludes the sterilization sequence after a sufficient FO sterilization dose is delivered to the sterilization loop, e.g., after fifteen to twenty minutes of sterilization recirculation at 120° C. or higher.

[0086] For disinfection, which may again occur before or after or overlap with the sterilization sequence, it is contemplated that control unit 50 receiving feedback from temperature sensor 36b cause disinfection heater 26b to heat the disinfection loop fluid (e.g., leftover fresh or used PD fluid) to a desired sterilization temperature of, for example, 65° C. or 75° C. or higher.

[0087] PD fluid pump 24 pumps disinfection loop fluid (e.g., leftover fresh or used PD fluid) back and forth between the used PD fluid sides of volumetric balancing chambers 40a and 40b, and throughout the disinfection loop, causing heated disinfection loop fluid (e.g., leftover fresh or used PD fluid) in the disinfection loop to be circulated back and forth to contact and disinfect all areas of the disinfection loop. The areas of the disinfection loop contacted with heated disinfection loop fluid (e.g., leftover fresh or used PD fluid) include valves 28j to 28o and associated lines, the used PD fluid sides of volumetric balancing chambers 40a and 40b, and ports 46b and 46c. Any one or more or all of valves 28j to 28o may be toggled open and closed (two-way) or toggled between positions or orientations (three-way) during the disinfection sequence to aid the disinfection. Control unit 50 concludes the disinfection sequence after a sufficient AO disinfection dose is delivered to the disinfection loop, e.g., after forty-five minutes at 75° C. or higher, assuming a disinfection loop volume of around 100 to 150 milliliters. Larger or smaller disinfection loop volumes would require longer and shorter disinfection times, which is due primarily to longer or shorter warmup times associated with larger or smaller disinfection loop volumes.

[0088] Referring now to FIG. 3, PD fluid machine 20b of system 10b illustrates an alternative embodiment of the present disclosure. PD fluid machine 20b of system 10b includes each of the features, structure and alternatives described above for PD fluid machine 20a of system 10a. All such structure, functionality and alternatives are incorporated by reference into PD fluid machine 20b of system 10b.

[0089] In PD fluid machine 20a of system 10a, air in the fresh and used PD fluid sides of the system tends to collect in volumetric balancing chambers 40a and 40b. The air may be detected using pressure sensors 34a and 34b. Once the amount of air in volumetric balancing chambers 40a and 40b reaches a threshold, control unit 50 causes the air to be purged to a drain container or house drain via drain line 112 (air on the fresh PD side may be pushed into the used PD fluid side via return lumen 108b of patient line 108 and from there to drain).

[0090] To prevent or mitigate air entering volumetric balancing chambers 40a and 40b, PD fluid machine 20b of system 10b provides a fresh PD fluid airtrap 62a on the fresh PD fluid side of machine 20b and a used PD fluid airtrap 62b on the used PD fluid side of machine 20b. Each of airtraps 62a and 62b operates with one or more level sensor 64a and 64b that output to control unit 50. One or more level sensor 64a, 64b ensure(s) that a desired level or range of levels of fresh and used PD fluid are maintained in the respective airtrap. Level sensors 64a, 64b may be ultrasonic sensors or any other type of sensor that can detect between PD fluid and air.

[0091] Airtraps 62a and 62b allow more air to be tolerated in system 10b. More air may be collected before control unit 50 needs to perform an air purge routine. Also, when an air purge routine is needed, air may be purged from airtraps 62a and 62b during a dwell phase of the treatment. Airtraps 62a and 62b are sized in an embodiment to hold a full volume's worth of air generated in each patient fill (airtrap 62a) and each patient drain (airtrap 62b) so that the purging of air may occur during a patient dwell. It is a goal of system 10b to attempt to trap air in airtraps 62a and 62b prior to the air reaching balancing chambers 40a and 40b, which could affect their volumetric accuracy.

[0092] Referring now to FIG. 4, PD fluid machine 20c of system 10c illustrates another alternative embodiment of the present disclosure. PD fluid machine 20c of system 10c includes each of the features, structure and alternatives described above for PD fluid machines 20a and 20b of systems 10a and 10b. All such structure, functionality and alternatives are incorporated herein by reference into PD fluid machine 20c of system 10c. PD fluid machine 20c of system 10c includes airtraps 62a and 62b as discussed above for PD fluid machine 20b of system 10b. PD fluid machine 20c of system 10c removes two-way valve 28j in PD fluid machine 20b of FIG. 3. Also, two-way valve 28k in PD fluid machine 20b of FIG. 3 is a three-way valve in PD fluid machine 20c of FIG. 4. PD fluid machine 20c of FIG. 4 accordingly includes one less valve than PD fluid machine 20b of FIG. 3. It should be appreciated that those of skill in the art may be able to determine many different ways to valve PD systems of the present disclosure. PD fluid machine 20c of system 10c provides one example.

[0093] Referring now to FIG. 5, PD fluid machine 20d of system 10d illustrates yet another alternative embodiment of the present disclosure. PD fluid machine 20d of system 10d includes each of the features, structure and alternatives described above for PD fluid machines 20a to 20c of systems 10a to 10c, respectively. All such structure, functionality and alternatives are incorporated herein by reference into PD fluid machine 20d of system 10d. The primary difference with PD fluid machine 20d of system 10d is the provision of alternative airtraps 162a and 162b in the fresh PD fluid side and the used PD fluid side of PD machine 20d, respectively.

[0094] One issue with airtraps 62a and 62b of PD machines 20b and 20c is that they are stiff and may leak or squirt fresh or used PD fluid if a pressure exists above ambient in the surrounding fluid lines and a door of PD fluid machine 20d is opened. Such pressure building may occur after a disinfection/sterilization phase, for example, before the fluid temperature has a chance to cool. Present alternative airtraps 162a and 162b mitigate the pressure-building issue by providing flexible membranes 164. At the start of the “germs deactivation” (sterilization/disinfection) sequence, control unit 50 positions membranes 164 within airtraps 162a and 162b such that there a sufficient amount of air residing on the non-fluid contacting sides of membranes 164. When the “germs deactivation” sequence has been completed, the air on the non-fluid contacting sides of the back sides of the membranes 164 is released via control unit 50, e.g., through vent valve 28p for airtrap 162a and through vent valve 28q for airtrap 162b. The release of air from airtraps 162a and 162b relives pressure in the fresh and used PD fluid sides of PD machine 20c, respectively, without allowing air into system 10d that could destroy the germ-free status of the fresh and used sides after sterilization/disinfection.

[0095] 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. For example, while heat is disclosed as the mechanism for sterilization and disinfection, it should be appreciated that other types of disinfection are possible alternatively or additionally, such as, chemical disinfection and/or UV radiation. It is therefore intended that such changes and modifications be covered by the appended claims.