Patent Publication Number: US-2023137696-A1

Title: Dual lumen patient line system and method having kink detection

Description:
PRIORITY CLAIM 
     The present application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/274,693 filed Nov. 2, 2021, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present disclosure relates generally to medical fluid treatments and in particular to dialysis fluid treatments. 
     Due to various causes, a person&#39;s renal system can fail. Renal failure produces several physiological derangements. It is no longer possible to balance water and minerals or to excrete daily metabolic load. Toxic end products of metabolism, such as, urea, creatinine, uric acid and others, may accumulate in a patient&#39;s blood and tissue. 
     Reduced kidney function and, above all, kidney failure is 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 functions is critical to many people because the treatment is lifesaving. 
     One type of kidney failure therapy is Hemodialysis (“HD”), which in general uses diffusion to remove waste products from a patient&#39;s blood. A diffusive gradient occurs across the semi-permeable dialyzer between the blood and an electrolyte solution called dialysate or dialysis fluid to cause diffusion. 
     Hemofiltration (“HF”) is an alternative renal replacement therapy that relies on a convective transport of toxins from the patient&#39;s blood. HF is accomplished by adding substitution or replacement fluid to the extracorporeal circuit during treatment. The substitution fluid and the fluid accumulated by the patient in between treatments is ultrafiltered over the course of the HF treatment, providing a convective transport mechanism that is particularly beneficial in removing middle and large molecules. 
     Hemodiafiltration (“HDF”) is a treatment modality that combines convective and diffusive clearances. HDF uses dialysis fluid flowing through a dialyzer, similar to standard hemodialysis, to provide diffusive clearance. In addition, substitution solution is provided directly to the extracorporeal circuit, providing convective clearance. 
     Most HD, HF, and HDF treatments occur in centers. A trend towards home hemodialysis (“HHD”) exists today in part because HHD can be performed daily, offering therapeutic benefits over in-center hemodialysis treatments, which occur typically bi- or tri-weekly. Studies have shown that more frequent treatments remove more toxins and waste products and render less interdialytic fluid overload than a patient receiving less frequent but perhaps longer treatments. A patient receiving more frequent treatments does not experience as much of a down cycle (swings in fluids and toxins) as does an in-center patient, who has built-up two or three days&#39; worth of toxins prior to a treatment. In certain areas, the closest dialysis center can be many miles from the patient&#39;s home, causing door-to-door treatment time to consume a large portion of the day. Treatments in centers close to the patient&#39;s home may also consume a large portion of the patient&#39;s day. HHD can take place overnight or during the day while the patient relaxes, works or is otherwise productive. 
     Another type of kidney failure therapy is peritoneal dialysis (“PD”), which infuses a dialysis solution, also called dialysis fluid or PD fluid, into a patient&#39;s peritoneal chamber via a catheter. The PD fluid comes into contact with the peritoneal membrane in the patient&#39;s peritoneal chamber. Waste, toxins and excess water pass from the patient&#39;s bloodstream, through the capillaries in the peritoneal membrane, and into the PD fluid due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. An osmotic agent in the PD fluid provides the osmotic gradient. Used PD fluid is drained from the patient, removing waste, toxins and excess water from the patient. This cycle is repeated, e.g., multiple times. 
     There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis (“CAPD”), automated peritoneal dialysis (“APD”), tidal flow dialysis and continuous flow peritoneal dialysis (“CFPD”). CAPD is a manual dialysis treatment. Here, the patient manually connects an implanted catheter to a drain to allow used PD fluid to drain from the patient&#39;s peritoneal cavity. The patient then switches fluid communication so that the patient catheter communicates with a bag of fresh PD fluid to infuse the fresh PD fluid through the catheter and into the patient. The patient disconnects the catheter from the fresh PD fluid bag and allows the PD fluid to dwell within the patient&#39;s peritoneal cavity, wherein the transfer of waste, toxins and excess water takes place. After a dwell period, the patient repeats the manual dialysis procedure, for example, four times per day. Manual peritoneal dialysis requires a significant amount of time and effort from the patient, leaving ample room for improvement. 
     APD is similar to CAPD in that the dialysis treatment includes drain, fill and dwell cycles. APD machines, however, perform the cycles automatically, typically while the patient sleeps. APD machines free patients from having to manually perform the treatment cycles and from having to transport supplies during the day. APD machines connect fluidly to an implanted catheter, to a source or bag of fresh PD fluid and to a fluid drain. APD machines pump fresh PD fluid from a dialysis fluid source, through the catheter and into the patient&#39;s peritoneal chamber. APD machines also allow for the PD fluid to dwell within the chamber and for the transfer of waste, toxins and excess water to take place. The source may include multiple liters of dialysis fluid, including several solution bags. 
     APD machines pump used PD fluid from the patient&#39;s peritoneal cavity, though the catheter, to drain. As with the manual process, several drain, fill and dwell cycles occur during dialysis. A “last fill” may occur at the end of the APD treatment. The last fill fluid may remain in the peritoneal chamber of the patient until the start of the next treatment, or may be manually emptied at some point during the day. 
     The line leading from the APD machine to the patient often becomes kinked due to the often sleeping patient rolling over on the patient line or otherwise twisting it. The patient line may line may also become blocked internally, e.g., via fibrin or other patient substances collecting in the patient line. When this occurs, the APD machine typically sounds and alarm and pauses treatment. The patient has to be awakened to fix the problem. Pausing treatment and waking the patient lead to a more cumbersome treatment. It is accordingly desirable to provide an APD machine that can accurately detect patient line occlusions and provide accurate information regarding the occlusions so that the patient can be properly informed when an occlusion does occur. 
     SUMMARY 
     The automated peritoneal dialysis (“PD”) system and associated methodology of the present disclosure operates with a dual lumen patient line. The dual lumen patient line may be disinfected and reused for multiple treatments or may be discarded after treatment. In one embodiment, the dual lumens of the patient line merge together at the distal end of the patient line to form a single lumen in a connector that connects to the patient&#39;s transfer set and communicates fluidly with the patient&#39;s indwelling catheter. In an alternative embodiment, the dual lumens of the patient line do not merge together and instead connect respectively to separate lumens of the patient&#39;s transfer set and communicate fluidly with a dual lumen indwelling catheter to perform continuous flow peritoneal dialysis (“CFPD”). In CFPD, fresh PD fluid flows to the patient, while used PD fluid is removed from the patient. 
     Regardless of whether the dual lumens of the patient line merge into a single lumen upstream of the patient&#39;s transfer set or not, fresh PD fluid is delivered through one of the lumens of the dual lumen patient line via a PD fluid pump. The PD fluid pump may be an electrically operated piston, gear, membrane or centrifugal pump, which may be inherently volumetrically accurate so that a separate PD fluid volume measurement apparatus, such as a flowmeter, balance chamber or an apparatus using the ideal gas law, is not needed. Here, PD fluid flows through the body of the PD fluid pump, which is disinfected after treatment. In an alternative embodiment, the PD fluid pump includes a pump actuator that actuates a tube or flexible sheet through which the PD fluid flows. The pump actuator may for example be (i) a peristaltic pump actuator that operates with a pumping tube or (ii) a pneumatic or electromechanical pump actuator (e.g., stepper motor and piston) that operates with a flexible pumping sheet. The pump actuators are reusable and do not contact fluid so they do not need to be disinfected after treatment. The pumping tube or flexible sheet may be discarded after each treatment or may be disinfected and reused for multiple treatments. 
     The PD fluid pump may be bidirectional or unidirectional, and a single pump may be provided. The PD fluid pump may also be continuous. The PD fluid pump is controllable to pump PD fluid to and from the patient at or within a pressure limit, e.g., by controlling a level of current, a pulse width, or a pneumatic pressure to the PD fluid pump. A positive patient pressure limit may for example be one to five psig (e.g., two psig (14 kPa)). A negative patient pressure limit may for example be −1.0 psig to −3.0 psig (e.g., −1.3 psig (−9 kPa)). The PD fluid may be supplied from containers or bags that may hold different dextrose or glucose level dialysis fluids, such as 1.36% glucose dialysis fluid, 2.27% glucose dialysis fluid and/or a last bag of a different formulation of PD fluid, such as icodextrin. The PD fluid may be heated by a heater, e.g., an inline heater, which is able to heat PD fluid from room temperature to body temperature, e.g., 37° C., at a flowrate of at least 200 milliliters (“ml”)/minute. 
     PD fluid lines lead from the PD fluid pump to the dual lumen patient line. The PD fluid lines may be located inside of the PD machine or cycler and be reusable lines that are disinfected after treatment. The PD fluid lines may alternatively be mounted on the outside of the PD machine or cycler or mounted inside a door of the PD machine or cycler. Here, the PD fluid lines are typically single use disposable but could alternatively be disinfected after treatment for reuse. Any of the tubing inside or outside of the housing of the machine or cycler may be metal, e.g., stainless steel, or plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), cross-linked polyethylene (“PEX”), polyurethane (“PU”) or polycarbonate (“PC”). 
     One or more valves is/are provided along the PD fluid lines to open or occlude flow as desired. The valves may for example be electrically actuated solenoid valves, e.g., energized open for failsafe operation. Here, PD fluid flows through the body of the valve, which is disinfected after treatment for reuse. The valves may alternatively be pinch valves, having electromechanical or pneumatic valve actuators that pinch closed flexible tubing or a flexible sheet. Here, the valve actuators are reusable and do not contact fluid so they do not need to be disinfected after treatment. The flexible pumping tube or flexible sheet may be discarded after each treatment or may be disinfected and reused for multiple treatments. 
     A valve may be positioned along the PD fluid line that is in fluid communication with the return lumen of the dual lumen patient line and which leads to an inlet of the PD fluid pump. If such valve is closed during the occlusion pressure checking described next, then the return lumen of the dual lumen patient line is a static pressure line. If such valve is instead open during the occlusion pressure checking, then the return lumen of the dual lumen patient line may be a dynamic pressure line in which a closed loop is formed with the two lumens and the PD fluid lines interfacing between the PD fluid pump. 
     A pressure sensor is provided for each lumen of the dual lumen patient line and may be provided along the PD fluid lines interfacing between the PD fluid pump and the dual lumens. The pressure sensors may be inline, reusable pressure sensors having bodies through which the PD fluid flows. The pressure sensors may alternatively be pod pressure sensors, e.g., disposable, that are formed in the PD fluid line and have a fluid contacting side and an air transmission side that transmits the fluid pressure to a pressure transducer via an air transmission line. The pressure sensors may further alternatively be force sensors that accept flexible portions of their respective PD fluid lines, and which obtain pressure readings by measuring the force applied by the flowing fluid through the flexible portions. 
     The PD machine or cycler of the system of the present disclosure includes a control unit having one or more processor and one or more memory that controls the PD fluid pump, valves, heater and which receives signals or outputs from the pressure sensors and other sensors such as temperature sensors, conductivity sensors, a flow switch, and/or a leak detection sensor and process the signals or outputs as feedback. The control unit uses pressure feedback to control the dialysis fluid pump to run at safe patient pressure limits (mentioned above) during treatment and safe system limits during disinfection. The control unit uses temperature feedback to control the dialysis fluid heater to heat the fresh dialysis fluid to, e.g., body temperature. The control unit may use temperature compensated conductivity readings to analyze fresh and/or used dialysis fluid. 
     The control unit also monitors the outputs of the pressure sensors to look for an occlusion in the dual lumen patient line. If there is no flow in either of the lumens of the dual lumen patient line, then the control unit expects the pressures measured in each lumen to be the same or almost the same. The control unit knows that there is no flow in either of the lumens because the control unit knows when the PD fluid pump is actuated or not. When the PD fluid pump is pumping fluid, which the control unit commands and thus knows is taking place, and a closed loop is formed with the PD fluid return line and the inlet of the PD fluid pump, the control unit is programmed to expect the fluid pressure in the fill lumen to be different than the fluid pressure in the return lumen by a known amount of pressure drop in the closed loop caused by the flow of PD fluid. 
     If the pressure difference is different than the expected pressure drop difference, then the control unit runs an algorithm to determine if the difference in pressure is due to an occlusion in either or both of the dual lumens of the patient line. If the fill side pressure is at or above a predetermined amount, e.g., one psig (0.07 bar) or perhaps more, then the control unit determines that there is an occlusion in the fill lumen of the dual lumen patient line. If the return side pressure is lower than a predetermined amount, e.g., one psig (0.07 bar) or perhaps more, then the control unit determines that there is an occlusion in the return lumen of the dual lumen patient line. If both (i) the fill side pressure is at or above the predetermined amount, e.g., one psig (0.07 bar) or perhaps more, and (ii) the return side pressure is lower than the predetermined amount, e.g., one psig (0.07 bar) or perhaps more, then the control unit determines that there is an occlusion in the patient&#39;s transfer set. In any of the above scenarios, the control unit alarms at the machine or cycler and temporarily pauses treatment. A user interface at the machine or cycler under control of the control unit provides a message to the user detailing the location of the occlusion. 
     When the PD fluid pump is pumping fluid, which the control unit again knows is taking place, and a valve located along the PD fluid return line is closed causing the return fluid lumen to be static, the control unit is programmed to expect the fluid pressure in the fill lumen to be different than the fluid pressure in the return lumen by a known amount of pressure drop in the fill lumen only. If the pressure difference is different than the expected pressure drop difference (fill lumen only), then the control unit runs the same algorithm discussed above to determine if the difference in pressure is due to an occlusion in either one of the dual lumens of the patient line or perhaps in the patient&#39;s transfer set. 
     In light of the disclosure set forth herein, and without limiting the disclosure in any way, in a first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) system includes a housing; a PD fluid pump housed by the housing; a dual lumen patient line extending from the housing, the dual lumen patient line including a fill lumen and a return lumen; a PD fluid fill line in fluid communication with the fill lumen and an outlet of the PD fluid pump; a PD fluid return line in fluid communication with the return lumen and an inlet of the PD fluid pump; a fill pressure sensor configured to detect PD fluid pressure along the PD fluid fill line; a return pressure sensor configured to detect PD fluid pressure along the PD fluid return line; and a control unit configured to use outputs from the fill and return pressure sensors to determine if one of the fill lumen or the return lumen of the dual lumen patient line is occluded. 
     In a second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to operate the PD fluid pump and to determine if the PD fluid pump is pumping PD fluid or not. 
     In a third aspect of the present disclosure, which may be combined with any other aspect described herein, or portion thereof, the PD fluid fill line is located within the housing, along a surface of the housing, or behind a door provided by the housing. 
     In a fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD fluid return line is located within the housing, along a surface of the housing, or behind a door provided by the housing. 
     In a fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD system includes a user interface in operable communication with the control unit, the control unit configured upon determining an occlusion to cause the user interface to provide an alarm detailing whether the fill lumen is occluded, the return lumen is occluded, or a patient&#39;s transfer set is occluded. 
     In a sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to expect the outputs from the fill and return pressure sensors to be the same or almost the same if the PD fluid pump is not being actuated. 
     In a seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to expect the outputs from the fill and return pressure sensors to be different by a pressure drop amount if the PD fluid pump is being actuated. 
     In an eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD fluid pump, the PD fluid fill line, the fill lumen, the PD fluid return line and the return lumen form a closed loop, and wherein the pressure drop amount includes a pressure drop in both the fill lumen and the return lumen. 
     In a ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD system includes a valve under control of the control unit, the valve positioned to close the PD fluid return line, and wherein the pressure drop amount includes a pressure drop in the fill lumen but not the return lumen while the return lumen is closed by the valve. 
     In a tenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to determine (i) an occlusion in the fill lumen if the output from the fill pressure sensor is greater than an expected output from the fill pressure sensor by at least a first predetermined amount, (ii) an occlusion in the return lumen if the output from the return pressure sensor is less than an expected output from the return pressure sensor by at least a second predetermined amount, and (iii) an occlusion in a patient&#39;s transfer set if both (i) and (ii) are met. 
     In an eleventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the first and second predetermined amounts of the tenth aspect are at least substantially the same. 
     In a twelfth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to determine (i) an occlusion in the fill lumen if the output from the fill pressure sensor meets or exceeds a first predetermined pressure amount, (ii) an occlusion in the return lumen if the output from the return pressure sensor is less than a second predetermined pressure amount, and (iii) an occlusion in a patient&#39;s transfer set if both (i) and (ii) are met. 
     In a thirteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the first and second predetermined pressure amounts of the twelfth aspect are at least substantially the same. 
     In a fourteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the fill lumen and the return lumen of the dual lumen patient line merge into a single lumen in a connector located at the distal end of the dual lumen patient line. 
     In a fifteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the fill lumen and the return lumen of the dual lumen patient line extend into a connector located at the distal end of the dual lumen patient line, the connector configured to connect to a dual lumen patient transfer set for performing continuous flow peritoneal dialysis. 
     In a sixteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) system includes a housing; a PD fluid pump housed by the housing; a dual lumen patient line extending from the housing, the dual lumen patient line including a fill lumen and a return lumen; a fill pressure sensor configured to detect PD fluid pressure in the fill lumen of the dual lumen patient line; a return pressure sensor configured to detect PD fluid pressure in the return lumen of the dual lumen patient line; and a control unit configured to use outputs from the fill and return pressure sensors to determine if one of the fill lumen or the return lumen of the dual lumen patient line is occluded. 
     In a seventeenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, any of the features, functionality and alternatives described in connection with any one or more of  FIG.  1  or  2    may be combined with any of the features, functionality and alternatives described in connection with any other of  FIG.  1  or  2   . 
     It is accordingly an advantage of the present disclosure to provide an automated peritoneal dialysis (“PD”) machine or cycler having accurate occlusion detection. 
     It is another advantage of the present disclosure to provide a PD system having a dual lumen patient line. 
     It is a further advantage of the present disclosure to provide a PD machine or cycler that may employ durable fluid handling components that accept peritoneal dialysis fluid directly without having to operate with a disposable item, such as a tube or flexible sheeting. 
     It is yet another advantage of the present disclosure to provide a volumetrically accurate PD cycler. 
     It is yet a further advantage of the present disclosure to provide a PD machine or cycler having fluid pressure control pumping to and from the patient. 
     It is still a further advantage of the present disclosure to provide a relatively quiet PD machine or cycler. 
     Additional features and advantages are described in, and will be apparent from, the following Detailed Description and the Figures. The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the figures and description. Also, any particular embodiment does not have to have all of the advantages listed herein and it is expressly contemplated to claim individual advantageous embodiments separately. Moreover, it should be noted that the language used in the specification has been selected principally for readability and instructional purposes, and not to limit the scope of the inventive subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is a schematic view of one embodiment of a system during a patient fill or dwell, the system including an automated peritoneal dialysis (“PD”) machine or cycler having a dual lumen patient line. 
         FIG.  2    is a schematic view of the system of  FIG.  1    during a patient drain. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings and in particular to  FIG.  1   , an embodiment of an automated peritoneal dialysis (“PD”) system  10  and associated methodology of the present disclosure includes a PD machine or cycler  20 . Cycler  20  includes a housing  22  that holds reusable or durable flow components. Housing  22  may be made of metal, e.g., steel stainless steel, or aluminum, and/or plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), cross-linked polyethylene (“PEX”), polyurethane (“PU”) or polycarbonate (“PC”). Housing  22  is compact, lightweight and transportable in various embodiments. 
     Housing  22  holds a PD fluid pump  24 . PD fluid pump  24  may be an electrically operated piston, gear, membrane or centrifugal pump, which may be inherently volumetrically accurate so that a separate PD fluid volume measurement apparatus, such as a flowmeter, balance chamber or an apparatus using the ideal gas law, is not needed. Here, PD fluid flows through the body of durable PD fluid pump  24 , which is disinfected after treatment. In an alternative embodiment, PD fluid pump  24  includes a pump actuator that actuates a tube or flexible sheet of a disposable set through which the PD fluid flows. Pump actuator  24  may for example be (i) a peristaltic pump actuator that operates with a pumping tube or (ii) a pneumatic or electromechanical pump actuator (e.g., stepper motor and piston) that operates with a flexible pumping sheet. The pump actuators are reusable and do not contact fluid so they do not need to be disinfected after treatment. The pumping tube or flexible sheet may be discarded after each treatment or may be disinfected and reused for multiple treatments. In any embodiment discussed above, PD fluid pump  24  may be bidirectional or unidirectional, and a single pump may be provided. PD fluid pump  24  may also be continuous. 
     Housing  22  also holds plural valves, e.g., valve  26   a  to  26   c  located along the PD fluid lines to open or occlude flow as desired. It should be appreciated that machine or cycler  20  provides additional valves, which are not shown for ease of illustration. Nevertheless, each of the valves, including valves  26   a  to  26   c  may be electrically actuated solenoid valves, e.g., energized open for failsafe operation. Here, PD fluid flows through the bodies of valves  26   a  to  26   c , which are disinfected after treatment for reuse. Valves  26   a  to  26   c  may alternatively be pinch valve actuators, e.g., electromechanical or pneumatic valve actuators that pinch closed flexible tubing or a flexible sheet. Here, valve actuators  26   a  to  26   c  are reusable and do not contact fluid so they do not need to be disinfected after treatment. The flexible pumping tubing or flexible sheeting may be discarded after each treatment or may be disinfected and reused for multiple treatments. 
     In the illustrated embodiment of  FIGS.  1  and  2   , a return valve  26   a  is positioned along an internal, reusable return line  28   a , which is in fluid communication with a return lumen  40   r  of a dual lumen patient line  40 . Reusable PD fluid return line  28   a  leads to an inlet of PD fluid pump  24 . If return valve  26   a  is closed during an occlusion pressure checking sequence described below, then return lumen  40   r  of dual lumen patient line  40  is a static pressure line. If return valve  26   a  is instead open during the occlusion pressure checking, then return lumen  40   r  of dual lumen patient line  40  may be a dynamic pressure line in which a closed loop is formed with the two lumens  40   f  and  40   r  and reusable PD fluid lines  28   a  and  28   b  interfacing with PD fluid pump  24 . 
     Machine or cycler  20  of system  10  in the illustrated embodiment of  FIGS.  1  and  2    also includes a fill valve  26   b  located along a reusable PD fluid fill line  28   b  and a drain valve  26   c  located along a reusable PD fluid drain line  28   c . In  FIG.  1   , drain valve  26   c  is closed and fill valve  26   b  is open (return valve  26   a  may be open or closed) to prevent fresh PD fluid from being delivered to drain and to allow the fresh PD fluid to be delivered along PD fluid fill line  28   b  and fill lumen  40   f  of dual lumen patient line  40  to patient P. In  FIG.  2   , return and drain valves  26   a  and  26   c  are open while and fill valve  26   b  is closed to prevent used PD fluid from being returned to patient P and to instead allow the used PD fluid to be removed from patient P and delivered along return lumen  40   r  of dual lumen patient line  40 , PD fluid return line fill line  28   b  and PD fluid drain line  28   c  to a house drain or drain container  106 . 
     In the illustrated embodiment, housing  22  also houses a pressure sensor  30   a ,  30   b  provided for each lumen  40   r ,  40   f  of dual lumen patient line  40 . Pressure sensors  30   a ,  30   b  reside along reusable PD fluid lines  28   a ,  28   b , respectively, which interface between PD fluid pump  24  and the dual lumens. Pressure sensors  30   a ,  30   b  may be inline, reusable pressure sensors having durable bodies through which the PD fluid flows. Pressure sensors  30   a ,  30   b  may alternatively be pod pressure sensors, e.g., disposable, which are formed along their respective PD fluid line  28   a ,  28   b  and have a fluid contacting side and an air transmission side that transmits the fluid pressure to a pressure transducer via an air transmission line. Pressure sensors  30   a ,  30   b  may further alternatively be force sensors that accept flexible portions of respective PD fluid lines  28   a ,  28   b , and which obtain pressure readings by measuring the force applied by the flowing fluid through the flexible portions. 
     In the illustrated embodiment, housing  22  also houses an inline heater  32 , which is positioned to heat fresh PD fluid prior to being delivered to patient P. Inline heater  32  is in one embodiment able to heat PD fluid from room temperature to body temperature, e.g., 37° C., at a flowrate of at least 200 milliliters (“ml”)/minute. In alternative embodiments, system  10  may employ batch heating, e.g., which occurs in a supply or dedicated heating container or bag instead of inline heater  32 . One or more upstream or downstream temperature sensor (not illustrated) may be provided for outputting feedback and possibly feedforward information for the control of the PD fluid heater. System  10  may include other sensors, such as conductivity, priming, level sensors, a flow switch, and/or a leak detection sensor (not illustrated). 
       FIGS.  1  and  2    illustrate that PD machine or cycler  20  of system  10  of the present disclosure includes a control unit  50  having one or more processor  52  and one or more memory  54  that controls PD fluid pump  24 , valves  26   a  to  26   c  (and any other valves), inline heater  32 , and which receives signals or outputs from pressure sensors  30   a ,  30   b  and any of the other sensors listed above and processes the signals or outputs for feedback and/or display. Control unit  50  uses pressure feedback from pressure sensors  30   a ,  30   b  for the occlusion detection discussed below and to control dialysis fluid pump  24  to run at or within safe patient pressure limits during treatment, e.g., by controlling a level of current, a pulse width, or a pneumatic pressure to PD fluid pump  24 . A positive patient pressure limit may for example be one to five psig (e.g., two psig (14 kPa)). A negative patient pressure limit may for example be −1.0 psig to −3.0 psig (e.g., −1.3 psig (−9 kPa)). Control unit  50  uses temperature feedback to control dialysis fluid heater  32  to heat the fresh dialysis fluid to, e.g., body temperature or 37° C. Control unit  50  may use temperature compensated conductivity readings to analyze fresh and/or used dialysis fluid. 
     Control unit  50  also includes a video controller  56  that interfaces with a user interface  58 , which may include a display screen  60  operating with a touchscreen and/or one or more electromechanical button, such as a membrane switch. User interface  58  may also include one or more speaker for outputting alarms, alerts and/or voice guidance commands. User interface  58  may be provided with cycler  20  as illustrated in  FIGS.  1  and  2    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&#39;s or clinician&#39;s server interfacing with a doctor&#39;s or clinician&#39;s computer. 
     Dual lumen patient line  40  may be disinfected and reused for multiple treatments or may be discarded after treatment. In one embodiment, dual lumens  40   f  and  40   r  of patient line  40  merge together at the distal end of the patient line to form a single lumen in a connector  42  that connects to the patient&#39;s transfer set  44  and communicates fluidly with the patient&#39;s indwelling catheter. In an alternative embodiment, dual lumens  40   f  and  40   r  of patient line  40  do not merge together and instead connect respectively to separate lumens of the patient&#39;s transfer set  44  and communicate fluidly with a dual lumen indwelling catheter to perform continuous flow peritoneal dialysis (“CFPD”). In CFPD, fresh PD fluid flows to the patient, while used PD fluid is removed from the patient. Regardless of whether dual lumens  40   f  and  40   r  of patient line  40  merge into a single lumen upstream of the patient&#39;s transfer set  44  or not, fresh PD fluid is delivered through fill lumen  40   f  of dual lumen patient line  40  via PD fluid pump  24 . 
     System  10  provides a disposable set  100  for operation with cycler  20 . Disinfecting and reusing dual lumen patient line  40  reduces the amount of disposable items needed with disposable set  100 . In such case, disposable set  100  includes one or more supply container or bag  102  having a disposable supply line  104  that connects to one or more internal and reusable supply line  28   s  located within housing  22 . In an alternative embodiment, the at least one supply line  104  is reusable and has a distal end configured to plug into cycler  20  after treatment to create a closed loop for disinfection. The PD fluid supplied from at least one supply container or bag  102  may hold different dextrose or glucose level dialysis fluids, such as 1.36% glucose dialysis fluid, 2.27% glucose dialysis fluid and/or a last bag of a different formulation of PD fluid, such as icodextrin. Disposable set  100  may also include a drain container or bag  106  having a disposable drain line  108  that connects to reusable PD fluid drain line  28   c  located within housing. Drain container or bag  106  may alternatively be eliminated using a house drain, such as a toilet or bathtub. Drain line  108  may alternatively be reusable and have a distal end configured to plug into cycler  20  after treatment to create a closed loop for disinfection. 
     Reusable PD fluid lines  28   a  to  28   d  are illustrated as being located inside of housing  22  but may alternatively be mounted on an outer surface of the housing or be mounted inside a door of PD machine or cycler  20 . Here, the PD fluid lines  28   a  to  28   d  are typically single use disposable and operate with face mounted valves but could alternatively be disinfected after treatment for reuse. Any of the tubing located inside or outside of housing  22  may be metal, e.g., stainless steel, or plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), cross-linked polyethylene (“PEX”), polyurethane (“PU”) or polycarbonate (“PC”). 
     Occlusion Detection 
     Control unit  50  of system  10  is also configured to monitor the outputs of pressure sensors  30   a ,  30   b  to look for an occlusion in dual lumen patient line  40 . If there is no flow in either lumen  40   f  or  40   r  of dual lumen patient line  40 , then control unit  50  expects the pressures measured in each lumen by pressure sensors  30   a ,  30   b  to be the same or almost the same. Control unit  50  knows when there is no flow in either of lumens  40   f  or  40   r  because control unit  50  commands PD fluid pump  24  and thus knows when it is actuated or not. 
     In  FIG.  1   , when PD fluid pump  24  is filling patient P with fresh PD fluid, which control unit  50  commands and thus knows is taking place, and a suspected line kink or other partial or full occlusion is detected by control unit  50 , a dynamic closed loop may be formed with PD fluid pump  24 , reusable PD fluid lines  28   a  and  28   b , and dual lumen patient line  40  return and patient valves  26   a  and  26   b  open and drain valve  26   c  closed. Control unit  50  is programmed here to expect the fluid pressure in fill lumen  40   f , as measured by pressure sensor  30   b , to be different than the fluid pressure in return lumen  40   r , as measured by pressure sensor  30   a , by a known amount of pressure drop (e.g., empirically determined) in the closed loop caused by the flow of fresh PD fluid. As mentioned above, lumens  40   f  and  40   r  converge to a single lumen at connector  42 , allowing pressure sensor  30   a  to also see positive filling pressure when both lumens  40   f  and  40   r  are fully primed. If the pressure difference between the readings of pressure sensors  30   a  and  30   b  is different than the expected pressure drop difference, e.g., by more than a set margin of error, then control unit  50  in an embodiment runs an algorithm to determine if the mismatch in pressure difference is due to an occlusion in either or both of the lumens  40   f  and  40   r  of patient line  40 . If the fill lumen pressure reading at pressure sensor  30   b  is at or above a predetermined amount, e.g., one psig (0.07 bar) or perhaps more, then control unit  50  determines that there is an occlusion in fill lumen  40   f  of dual lumen patient line  40 . If the return lumen pressure reading at pressure sensor  30   a  is lower than a predetermined amount, e.g., one psig (0.07 bar) or perhaps more, then control unit  50  determines that there is an occlusion in return lumen  40   r  of dual lumen patient line  40 . If both (i) the fill side pressure sensor reading at pressure sensor  30   b  is at or above the predetermined pressure, e.g., one psig (0.07 bar) or perhaps more, and (ii) the return side pressure sensor reading at pressure sensor  30   a  is lower than the predetermined pressure, e.g., one psig (0.07 bar) or perhaps more, then control unit  50  determines that there is an occlusion in transfer set  44  of patient P. 
     In any of the above scenarios, control unit  50  alarms at user interface  58  of machine or cycler  20  and temporarily pauses treatment. User interface  58  under control of the control unit  50  may for example provide an audio, visual or audiovisual message to the user detailing the location(s) of the occlusion. 
     In the patient drain of  FIG.  2   , where PD fluid pump  24  removes used PD fluid from patient P, which control unit  50  again knows is taking place, return and drain valves  26   a  and  26   c  are open while fill valve  26   b  is closed. Pressure sensor  30   b  can nevertheless sense negative pressure due to the convergence of lumens  40   f  and  40   r  to a single lumen at connector  42 . Here, fill lumen  40   f  is a static line. A pressure drop in negative pressure (which can be determined empirically and stored in control unit  50 ) occurs beginning at the inlet of PD fluid pump  24  (highest negative pressure) and extends through reusable PD fluid return line  28   a  and return lumen  40   r  to the convergence point at connector  42  (lowest negative pressure), which is in essence the pressure that pressure sensor  30   a  sees via static negative pressure fill lumen  40   f  If the measured pressure drop between pressure sensors  30   a  and  30   b  is less than expected (e.g., by a margin of error), then control unit  50  determines that there is an occlusion in return lumen  40   r  and alarms the patient or user in a manner described herein. If the measured pressure drop between pressure sensors  30   a  and  30   b  is less than expected (e.g., by a margin of error), then control unit  50  determines that there is a leak, for example, at connector  42 . 
     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. It is therefore intended that any or all of such changes and modifications may be covered by the appended claims.