PERITONEAL DIALYSIS SYSTEM INCLUDING PERISTALTIC PUMP

A peritoneal dialysis (“PD”) system includes a cycler having a peristaltic pump actuator; a disposable set including a pressure sensing manifold including first and second pressure sensing pods, a drain line and a first dialysis fluid/heater container line in fluid communication with the first pressure sensing pod, and at least one dialysis fluid container line and a patient line in fluid communication with the second pressure sensing pod; and a control unit programmed to operate the peristaltic pump actuator (i) in a first direction to pump fresh dialysis fluid along the at least one additional dialysis fluid container line into the first dialysis fluid/heater line and (ii) in a second direction to pump heated fresh dialysis fluid along the first dialysis fluid/heater line into the patient line. The pump actuator may be operated in the first direction again to pump used dialysis fluid from the patient to a drain.

PRIORITY CLAIM

The present application claims priority to and the benefit of IN Application No. 202041056330, filed Dec. 24, 2020, the entirety of which is herein incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to medical fluid treatments and in particular to dialysis fluid treatments.

BACKGROUND

Due to various causes, a person'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'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'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'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' worth of toxins prior to a treatment. In certain areas, the closest dialysis center can be many miles from the patient's home, causing door-to-door treatment time to consume a large portion of the day. Treatments in centers close to the patient's home may also consume a large portion of the patient'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, into a patient's peritoneal chamber via a catheter. The dialysis fluid is in contact with the peritoneal membrane in the patient's peritoneal chamber. Waste, toxins and excess water pass from the patient's bloodstream, through the capillaries in the peritoneal membrane, and into the dialysis 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 or spent dialysis 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 or spent dialysis fluid to drain from the peritoneal chamber. The patient then switches fluid communication so that the patient catheter communicates 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 and allows the dialysis fluid to dwell within the peritoneal chamber, 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.

Automated peritoneal dialysis (“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 dialysis fluid and to a fluid drain. APD machines pump fresh dialysis fluid from a dialysis fluid source, through the catheter and into the patient's peritoneal chamber. APD machines also allow for the dialysis 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 or spent dialysate from the patient's peritoneal cavity, though the catheter, and to the 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.

Known APD systems include a machine or cycler that accepts and actuates a pumping cassette having a hard part and a soft part that is deformable for performing pumping and valving operations. Sealing the fluid disposable cassette with a pneumatic path via a gasket to provide actuation has proven to be a potential field issue, which can delay treatment start time and affect user experience. Pneumatic cassette systems also produce acoustic noise, which may be a source of customer dissatisfaction.

For each of the above reasons, an improved APD machine is needed.

SUMMARY

The present disclosure sets forth a streamlined automated peritoneal dialysis (“APD”) cycler and associated system providing a peristaltic pump and disposable set that organizes tubing and performs many functions discussed below. The cycler of the system in one embodiment includes a peristaltic pump actuator that is capable of pumping in two directions. Flow in either direction advances through a pressure sensing manifold, which is part of an overall disposable set, and which may be separated into two pressure sensing pods, a first pressure sensing pod and a second pressure sensing pod. Both pressure sensing pods include a pressure sensing diaphragm that separates a liquid side for receiving dialysis fluid (fresh unheated dialysis fluid, fresh heated dialysis fluid and used dialysis fluid) from a pressure transmission side that holds a transmission fluid (e.g., air) for transmitting fluid pressure to a pressure transducer. The pressure sensing pods sense both positive and negative fluid pressure and output pressure signals to a control unit that uses a control algorithm configured to control the speed of a peristaltic pump actuator to ensure that the pumping pressure to the patient is within a safe limit, e.g., +1.5 psig to +9 psig for positive pressure pumping to the patient and −1.0 psig to −3 psig for negative pressure pumping from the patient. Pumping to and from the heater container or to drain may be performed at higher pressures if desired. The pumping pressures are controlled in an embodiment using feedback from the pod pressure sensors in an algorithm, e.g., using proportional, integral and derivative (“PID”) routine, which determines how much current to deliver to the peristaltic pump actuator. The pressure readings from the pressure pods may be used as feedback (i) continuously over the entire course of a patient fill or drain, (ii) only at critical times such as the beginning and end of a fill or drain, (iii) or at such critical times in combination with intermittent or periodic pressure checks during a middle portion of a fill or drain.

In one embodiment, the first pressure sensing pod operates with a drain line and a first dialysis fluid/heater container line, while the second pressure sensing pod operates with a patient line and second and third additional dialysis fluid lines. The drain line may run to a house drain (toilet, bathtub or sink) or to a drain container. The first dialysis fluid container is placed atop a batch heater of the cycler, e.g., a resistive plate heater, for a first patient fill. After the first dialysis fluid from the first container is heated and delivered to the patient, fresh dialysis fluid is pulled from a second or third dialysis fluid container and is delivered to the first dialysis fluid container for heating (e.g., while the first solution fluid dwells within the patient).

In an alternative embodiment, the batch heater is replaced with an inline heater provided by the cycler, which heats fresh dialysis fluid as it flows through the patient line to the patient. The batch and inline dialysis fluid heaters both operate with one or more temperature sensor to sense the temperature of the heated, fresh dialysis fluid to use as feedback to the control unit for controlling the heater, e.g., via a PID algorithm.

Each of the fluid lines mentioned above may be placed in a pinch valve provided by the cycler, which are each under selective control of the control unit in one embodiment. The pinch valves may be electrically actuated solenoid valves that energize open for fail safe operation. In an alternative embodiment, the pinch valves are replaced by multiway valves, e.g., stopcock valves, which operate with the pressure sensing manifold and the fluid lines. The multiway valves selectively allow flow into and out of desired ports of the pressure sensing pods. It should be appreciated that in certain instances, the rollers of the peristaltic pump actuator may also be used as an occluder or valve, which may reduce the number of valves needed and act as a backup in case of a valve malfunction.

Regardless of the type of valves, the control of the valves in combination with the direction of the peristaltic pump actuator dictates the direction of fluid flow. Different fluid paths include (i) from the first dialysis fluid/heater container to the patient, (ii) from either of the second or third dialysis fluid containers to the first dialysis fluid/heater container, and (iii) from the patient to drain, e.g., house drain or drain container.

Combinations of fluid paths (i) to (iii), or portions thereof, are used for priming the disposable set prior to treatment. One or more priming or air sensor may be provided by the cycler, e.g., an optical or capacitance sensor, for detecting the presence of liquid. The one or more priming or air sensor is located so as to operate with (i) the patient line (to determine when the patient line is fully primed prior to connection with the patient's catheter and to look for air during treatment) and (ii) the heating line (e.g., to look for air during treatment that may come out of solution due to fluid heating).

The cycler may further provide a flow sensor that invasively or non-invasively measure flowrate, e.g., along the patient line. The control unit of the cycler may integrate the measured flowrate to determine a volume of fresh dialysis fluid delivered to the patient and a volume of used dialysis fluid removed from the patient. The control unit also determines the difference between those values to arrive at an amount of ultrafiltration (“UF”) removed from the patient. In an alternative embodiment, a weigh scale provided with the dialysis fluid heater may be used to weigh fresh dialysis fluid delivered to the patient and used dialysis fluid removed from the patient. A single weigh scale may be used with the heating container for fresh dialysis fluid and the drain container for used dialysis fluid. Alternatively, separate dedicated fresh dialysis fluid and used dialysis fluid scales may be provided.

In one embodiment, the control unit includes one or more processor, one or more memory and a video controller operating with a user interface provided to control each of the peristaltic pump actuator, the dialysis fluid valves and the heater, and to receive signals from each of the pressure sensing pods, the priming or air sensor, the flow or weight sensors if provided, and one or more temperature sensor associated with the batch or inline heater. The user interface may be provided with a touchscreen and/or electromechanical pushbuttons to allow the user or patient to enter parameters for treatment and a display screen for providing information, such as treatment status information.

The control unit may also be programmed to monitor for a patient empty detection based on a pressure monitoring algorithm using measurements taken at the pressure sensing manifold. A characteristic increase in negative or suction pressure in the patient line at the end of a patient drain as measured by at least one of the pressure sensing pods indicates a patient empty condition to the control unit. A fluid pushback within the patient line may be employed as part of the patient empty algorithm. The patient empty detection is believed to be relatively quick, which reduces the amount of time that the patient is subjected to increased negative patient pressures.

The control unit of the cycler may also detect a patient line occlusion based on a pressure rise or decay algorithm. Again, a characteristic increase in suction or negative pressure in the patient line measured by at least one of the pressure sensing pods during a patient drain indicates an occlusion to the control unit, while a rise in positive pressure in the patient line measured by at least one of the pressure sensing pods during a patient fill indicates an occlusion to the control unit. Fluid pushback attempts within the patient line may again be employed as a result of the occlusion algorithms.

It is contemplated that the peristaltic pumping system of the present disclosure allows for a partial or perhaps even a full PD fluid flowrate to be maintained even during partial negative and positive occlusions. In this manner, treatment times may be maintained or almost maintained even when an occlusion is present. Thus, the usual response to an occlusion, namely to stop treatment, wake the patient, and instruct the patient to clear the occlusion if possible, is not necessarily the response with the system of the present disclosure. If, for example, the drain or fill is almost complete, the system of the present disclosure may determine that it is best to complete the fill or drain at the present flowrate and then try to clear the occlusion once the drain or fill is completed.

The control unit may further additionally be programmed to perform a patient fill according to a fill profile in which a speed of the peristaltic pump actuator operating in the second direction is increased during a middle portion of the patient fill. The control unit may still further additionally be programmed to perform a patient drain according to a drain profile in which a speed of the peristaltic pump actuator operating in the first direction is increased during a middle portion of the patient drain. In any case, the peristaltic pumping system of the present disclosure provides a wide range of flowrates, e.g. from less than ten mL/min to greater than 350 mL/min, while ensuring that positive or negative patient pressures are maintained within limits. The peristaltic pumping is also relatively smooth, allowing for minimal flow pulsation across treatment.

The pressure sensing manifold, the fluid lines and fluid containers of the disposable set may be made of one or more plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), polyurethane (“PU”) or polycarbonate (“PC”). The housing of the cycler may be made of any of the above plastics, and/or of metal, e.g., stainless steel, steel and/or aluminum.

In light of the disclosure set forth herein, and without limiting the disclosure in any way, in a first aspect, which may be combined with any other aspect described herein, or portion thereof, a peritoneal dialysis system includes (i) a cycler having a peristaltic pump actuator; a disposable set including a pressure sensing manifold including first and second pressure sensing pods, a drain line and a first dialysis fluid/heater container line in fluid communication with the first pressure sensing pod, and at least one additional dialysis fluid container line and a patient line in fluid communication with the second pressure sensing pod; and a control unit programmed to operate the peristaltic pump actuator (i) in a first direction to pump fresh dialysis fluid along the at least one additional dialysis fluid container line into the first dialysis fluid/heater line and (ii) in a second direction to pump heated, fresh dialysis fluid along the first dialysis fluid/heater line into the patient line.

In a first aspect, which may be combined with any other aspect described herein, or portion thereof, the peritoneal dialysis system includes a peristaltic pumping tube in fluid communication with the first and second pressure sensing pods.

In a third aspect, which may be combined with any other aspect described herein, or portion thereof, at least one of the drain line or the first dialysis fluid/heater container line is connected to a port extending from the first pressure sensing pod.

In a fourth aspect, which may be combined with any other aspect described herein, or portion thereof, at least one of the at least one additional dialysis fluid container line or the patient line is connected to a port extending from the second pressure sensing pod.

In a fifth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to use an output from the first pressure sensing pod as feedback to control pumping in the first direction at or below a positive system pressure limit for moving fresh dialysis fluid to a dialysis fluid/heater container.

In a sixth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to use an output from the second pressure sensing pod as feedback to control pumping in the first direction at or below a negative system pressure limit for moving fresh dialysis fluid to a dialysis fluid/heater container.

In a seventh aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to use an output from the second pressure sensing pod as feedback to control pumping in the second direction at or below a positive patient pressure limit for moving fresh dialysis fluid to a patient.

In an eighth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to use an output from the second pressure sensing pod as feedback to control pumping in the first direction at or below a negative patient pressure limit for removing used dialysis fluid from a patient.

In a ninth aspect, which may be combined with any other aspect described herein, or portion thereof, the cycler further includes at least one of a drain valve for operating with the drain line, a dialysis fluid/heater valve for operating with the first dialysis fluid/heater container line, at least one additional dialysis fluid container valve for operating with the at least one additional dialysis fluid container line, or a patient valve for operating with the patient line.

In a tenth aspect, which may be combined with any other aspect described herein, or portion thereof, the cycler further includes at least one of a first multiway valve actuator for operating with the first pressure sensing pod to allow flow to either the drain line or the first dialysis fluid/heater container line, or a second multiway valve actuator for operating with the second pressure sensing pod to allow flow to either the patient line or one of the at least one additional dialysis fluid container line.

In an eleventh aspect, which may be combined with any other aspect described herein, or portion thereof, the cycler further includes a heater under control of the control unit for heating fresh dialysis fluid delivered to a first dialysis fluid/heater container via the first dialysis fluid/heater container line.

In a twelfth aspect, which may be combined with any other aspect described herein, or portion thereof, at least one of the first and second pressure sensing pods includes a flexible diaphragm that transmits fresh and used dialysis fluid pressure fluctuations to a pressure transmission fluid.

In a thirteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the flexible diaphragm is further configured to dampen pressure fluctuations.

In a fourteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is further configured to end a patient drain when a negative pressure increase is sensed by the second pressure sensing pod while the peristaltic pump actuator is operated in the first direction to pump used dialysis fluid from the patient line.

In a fifteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to end the patient drain when the negative pressure increase is sensed and the control unit has determined that at least a threshold amount of used dialysis fluid has been removed from the patient.

In a sixteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is configured to end the patient drain when the negative pressure increase is sensed and after a pushback of used dialysis fluid in the patient line by the peristaltic pump actuator operating in the second direction fails to remove the negative pressure increase.

In a seventeenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is further configured to determine that a patient line occlusion has occurred when the second pressure sensing pod senses an increase in positive pressure in the patient line while moving fresh dialysis fluid to a patient.

In an eighteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is further configured to determine that a patient line occlusion has occurred when the second pressure sensing pod senses an increase in negative pressure in the patient line while removing used dialysis fluid from a patient.

In a nineteenth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is further configured to perform a patient fill according to a fill profile in which a speed of the peristaltic pump actuator operating in the second direction is increased for a middle portion of the patient fill.

In a twentieth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is further configured to perform a patient drain according to a drain profile in which a speed of the peristaltic pump actuator operating in the first direction is increased for a middle portion of the patient drain.

In a twenty-first aspect, which may be combined with any other aspect described herein, or portion thereof, the peristaltic pump actuator is positioned relative to the cycler such that the first and second pressure sensing pods, the drain line, the first dialysis fluid/heater container line, the at least one additional dialysis fluid container line and the patient are oriented at least substantially horizontally for treatment.

In a twenty-second aspect, which may be combined with any other aspect described herein, or portion thereof, the peristaltic pump actuator is located on a tray that slides into and out of the cycler.

In a twenty-third aspect, which may be combined with any other aspect described herein, or portion thereof, the peristaltic pump actuator is accessible from a top of the cycler.

In a twenty-fourth aspect, which may be combined with any other aspect described herein, or portion thereof, the peristaltic pump actuator is positioned relative to the cycler such that the first and second pressure sensing pods, the drain line, the first dialysis fluid/heater container line, the at least one additional dialysis fluid container line and the patient are oriented at least substantially vertically for treatment.

In a twenty-fifth aspect, which may be combined with any other aspect described herein, or portion thereof, the cycler further includes a plurality of valves, a first door configured to selectively cover the plurality of valves and a second door configured to selectively cover the peristaltic pump actuator.

In a twenty-sixth aspect, which may be combined with any other aspect described herein, or portion thereof, the first and second pressure sensing pods are spaced at least one of (i) symmetrically about or (ii) equidistant to the peristaltic pump actuator.

In a twenty-seventh aspect, which may be combined with any other aspect described herein, or portion thereof, a peritoneal dialysis system includes a first peristaltic pump actuator; a second peristaltic pump actuator; a disposable set including a first peristaltic pumping tube operable with the first peristaltic pump actuator, the first peristaltic pumping tube outputting to a second peristaltic pumping tube operable with the second peristaltic pump actuator; and a control unit programmed to operate a first speed of the first peristaltic pump actuator as a function of a second speed of the second peristaltic pump actuator.

In a twenty-eighth aspect, which may be combined with any other aspect described herein, or portion thereof, the function is constant or periodic.

In a twenty-ninth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is programmed to operate the second speed based on a set dialysis fluid flowrate.

In a thirtieth aspect, which may be combined with any other aspect described herein, or portion thereof, the control unit is programmed to operate the first peristaltic pump actuator so as to create a desired inlet pressure to the second peristaltic pumping tube.

In a thirty-first aspect, any of the features, functionality and alternatives described in connection with any one or more ofFIGS.1to17may be combined with any of the features, functionality and alternatives described in connection with any other ofFIGS.1to17.

It is accordingly an advantage of the present disclosure to provide an APD system having a peristaltic pump and valves that collectively reduce operating noise and which maintain and improve treatment time due to range of peristaltic pump ability.

It is another advantage of the present disclosure to provide an APD system that is portable to ultra-portable.

It is a further advantage of the present disclosure to provide an APD system that eliminates certain sealing issues present in known APD systems.

It is yet a further advantage of the present disclosure to provide an APD pump driven system that eliminates bulky pneumatic equipment associated with certain APD systems.

It is yet a further advantage of the present disclosure to provide an APD pump driven system that reduces noise relative to pneumatic systems.

It is yet another advantage of the present disclosure to provide an APD system that manages peritoneal dialysis fluid flow so as to be within safe and comfortable patient pressure limits.

Still another advantage of the present disclosure is to provide an APD system having improved empty detection, resulting in lower time of patient exposure to low pressure during empty detection.

Still a further advantage of the present disclosure is to provide an APD system having lessened flow pulsation for improved patient comfort.

Yet another advantage of the present disclosure is to provide an APD system that is suited for inline heating to further improve treatment time and reduce device size.

Yet a further advantage of the present disclosure is to provide an APD system having reduced disposable integrity test duration.

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.

DETAILED DESCRIPTION

Referring now to the drawings and in particular toFIG.1, an embodiment of system10includes an automated peritoneal dialysis (“APD”) cycler20ahaving a housing22, which uses peristaltic pumping in the illustrated embodiment, and which operates a disposable set100(seeFIGS.2and3). All rigid and flexible tubing portions of disposable set100may be made of one or more plastic, e.g., polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), polyurethane (“PU”) or polycarbonate (“PC”). Housing22of cycler20amay be made of any of the above plastics, and/or of metal, e.g., stainless steel, steel and/or aluminum.

Housing22is shown in phantom line to see the components of system10provided inside. In the illustrated embodiment, housing22is provided with a series of holes or slots24a,24b,24c,24dand24efor tubing of disposable set100to extend from the inside of housing22to the outside of the housing. While illustrated as round holes, the apertures may alternatively be slots that24a,24b,24c,24dand24ethat extend up along a front surface of housing22(see e.g., slots24aand24c), through an upper edge of the front surface, so that with the lid of cycler20alifted, the patient or caregiver may translatingly insert the tubes of disposable set100down into the slots, and wherein various tubes may be preconnected to the dialysis fluid containers or bags and possibly a drain container or bag.

FIG.1also illustrates that housing22of cycler20aof system10houses a peristaltic pump actuator30, which is variable speed and rotates in two directions in one embodiment. The peristaltic pumping tube operating with peristaltic pump actuator30extends to two pressure sensing pods112aand112b, which operate respectively with reusable pressure transducers26and28located within housing22. Multiple tubes extend from pressure sensing pods112aand112band individually through pinch valves40,42,44,46and48and from there through holes or slots24a,24b,24c,24dand24e. Pinch valves40,42,44,46and48in one embodiment are electrically actuated solenoid valves that energize open so as to operate in a fail safe manner. In an alternative embodiment discussed below, pinch valves40,42,44,46and48are replaced with multiway stopcock valves that interface directly with pressure sensing pods112aand112b.

FIG.1further illustrates that housing22of cycler20aof system10houses a heater34, which in one embodiment is attached to and openable with the lid of housing22. Heater34is in one embodiment a batch heater that heats an entire fill volume worth of fresh dialysis fluid, e.g., before treatment for a first patient fill and during a patient dwell for subsequent patient fills. One or more temperature sensor36aand36bis provided and located so as to measure the temperature of fresh dialysis fluid located within a container or bag placed on top of heater34. The output of one or more temperature sensor36aor36bis used in an embodiment as feedback, e.g., via a proportional, integral, derivative (“PID”) control routine, to control the power supplied to heater34in an attempt to heat the fresh dialysis fluid to body temperature, e.g., 37° C. Heater34in an alternative embodiment is an inline heater that heats the dialysis fluid flowing through a patient line or tube to the patient to body temperature.

Besides pressure transducers26and28and temperature sensors36aand36b, system10includes additional sensors discussed below. Each of the sensors of cycler20aof system10discussed herein outputs in one embodiment to a control unit50illustrated in FIG.1, which in addition controls the operation of peristaltic pump actuator30, batch heater34(or alternatively an inline heater), and pinch valves40,42,44,46and48(or alternatively the stopcock valves). Control unit50includes one or more processor52, one or more memory54and a video controller56that controls a user interface58, such as a touch screen user interface. User interface58may alternatively or additionally be a remote user interface, e.g., via a tablet or smartphone. Control unit50receives signals from pressure transducers26and28and uses the signals, e.g., via a PID control routine to control patient pumping pressure and other pumping pressures discussed herein via the control of current to peristaltic pump actuator30. Pressure readings from the pressure pod transducers26and28may be used as feedback to control unit50(i) continuously over the entire course of a patient fill or drain, (ii) only at critical times such as the beginning and end of a fill or drain, (iii) or at such critical times in combination with intermittent or periodic pressure checks during a middle portion of a fill or drain. In an example, if a pressure signal received at control unit50exceeds a certain value (positive or negative), depending on the condition of a partial occlusion, control unit50may be configured to lower the speed of peristaltic pump actuator30to a specified level, which may be a single level or multiple, e.g., two, levels. Such a pumping regime ensures that the control of peristaltic pump actuator30is not complex and is achievable.

Control unit50may also include a transceiver and a wired or wireless connection to a network (not illustrated), e.g., the internet, for sending treatment data to and receiving prescription instructions/changes from a doctor's or clinician's server interfacing with a doctor's or clinician's computer. The data sent to the doctor's or clinician's computer may be analyzed and/or converted to, or used to form, other data useful for analysis. Such data conversion is performed alternatively at control unit50.

FIGS.2and3each illustrate system10and are very similar, including the same components, which are numbered the same.FIGS.2and3illustrate peristaltic pump actuator30, batch heater34, temperature sensors36aand36b, and pinch valves40,42,44,46and48discussed above withFIG.1, each operating with control unit50. Pressure sensing pods112aand112bdiscussed inFIG.1are also illustrated inFIG.3. In the illustrated embodiment, pressure sensing pods112aand112bare provided as part of a single, e.g., rigid manifold110, which in turn is provided as part of an overall disposable set100. Disposable set100also includes a peristaltic pumping tube108, which is actuated by peristaltic pump actuator30and is connected at either end to pressure sensing pods112aand112bof rigid manifold110. In an embodiment, peristaltic pumping tube108has a shore hardness of at least77A and perhaps much higher and is formed of a mix of polymer resin molecular weight and plasticizer selected to provide desired springback properties. A higher shore hardness value and desired polymer mix enable the peristaltic pumping tube to spring open to its original shape more accurately and for a longer period of time during pumping. Peristaltic pump actuator30likewise has sufficient stiffness to operate the stiffer pumping tube.

System10employs additional measures to increase the accuracy of the peristaltic pumping provided by actuator30and peristaltic pumping tube108. For example, it is contemplated to increase the number of rollers of actuator30, e.g., from three to five or six, to reduce flow pulsatility. As discussed herein, pressure sensing pods112aand112balso dampen pulsatility and provide uniform boundary conditions, which enables the pump behavior to be systematic and have less asymmetry. Pressure sensing pods112aand112bin one embodiment are symmetrically located in an equidistant manner about peristaltic pump actuator30, further reducing asymmetry and its deviation. It is also contemplated for control unit50to operate peristaltic pump actuator30so that fluid resistance on a suction side of pump actuator30and pumping tube108during patient fills and drains is the same, providing hydraulic balancing that further reduces asymmetry.

Disposable set100further includes a drain line or tube120, a first fresh dialysis fluid/heating container or bag line or tube122, a patient line or tube124, a second dialysis fluid container or bag line or tube126and a third dialysis fluid container or bag line or tube128, which may be a last fill container or bag.

The primary difference betweenFIGS.2and3is the order in which the different lines or tubes extend from rigid manifold110. InFIGS.2and3, patient line or tube124is located in the same position relative to rigid manifold110. But inFIG.2, drain line or tube120is located on top, while first fresh dialysis fluid/heating container or bag line or tube122is located beneath drain line120. InFIG.3, first fresh dialysis fluid/heating container or bag line or tube122is located on top, while drain line or tube120is located beneath the bag/heating line122. Also, inFIG.2, third dialysis fluid container or bag line128is located above second dialysis fluid container or bag line126, while inFIG.3, second dialysis fluid container or bag line126is located above third dialysis fluid container or bag line128.FIGS.2and3illustrate that different lines or tubes may be located in different orientations. Also,FIG.1illustrates that rigid manifold110, pressure sensing pods112aand112band associated tubes108,120,122,124,126and128may be oriented horizontally during operation, whileFIGS.2and3illustrate that rigid manifold110, pressure sensing pods112aand112band associated tubes108,120,122,124,126and128are oriented vertically during operation.

In general, if disposable set100is door loading, such that it is mounted vertically on the cycler, it is desirable to position drain line120on top for better air management. If disposable set100is instead top loading, such that it is mounted horizontally onto the cycler, the positions of drain line120and dialysis fluid/heating line122are interchangeable. The positions of second dialysis fluid line126versus third dialysis fluid (last bag) line128are also generally interchangeable. Patient line124and third dialysis fluid line128(inFIG.2) or patient line124and second dialysis fluid line126(inFIG.3) are positioned next to each other so that a single multiway or “3 by 2” pinch valve may be provided to control both lines, reducing the number of valve motors if motorized valves are employed. Patient line124may be provided above or below third dialysis fluid line128(inFIG.2) or above or below second dialysis fluid line126(inFIG.3).

InFIG.3for example, with a reduced number of valves using a “3 by 2” valve, either patient line124or second dialysis fluid line126bag will be open, while third dialysis fluid line128(e.g., for a last fill of fluid different from that in second dialysis fluid line126) has independent control. For example, during a patient fill using open patient line124, second and third dialysis fluid lines126and128are closed. During a heater bag replenish using open second dialysis fluid line126, patient line124and third dialysis fluid line128are closed.

Providing independent valves instead allows the ordering of patient line124, second dialysis fluid line126and third dialysis fluid line128to be completely flexible. The APD systems for cyclers20ato20fare configurable to have many different valve options, for example, (i) two “3 by 2” pinch valves and a single pinch valve (three motors), (ii) five pinch valves (five motors but independent line control), (iii) stopcock valves (two motors and independent line control) or (iv) combinations thereof.

Regardless of the orientation of rigid manifold110, pressure sensing pods112aand112band associated tubes, and regardless of the relative position of drain line120versus first dialysis fluid/heating line122and the relative position of second dialysis fluid line126versus third dialysis fluid line128, it is contemplated that the fluid lines be positioned according to the following guidelines. First, patient line or tube124needs to be located on the other side of peristaltic pump actuator30from drain line or tube120, so that peristaltic pump actuator30inFIGS.2and3may be rotated in the clockwise direction to remove effluent from patient P to the drain. Second, first fresh dialysis fluid/heating container or bag line or tube122needs to be located on the other side of peristaltic pump actuator30from second and third dialysis fluid lines or tubes126and128, so that peristaltic pump actuator30inFIGS.2and3may be rotated again in the clockwise direction to pump fresh dialysis fluid along second and third dialysis fluid lines or tubes126and128into first fresh dialysis fluid/heating container or bag line or tube122in subsequent fills for heating. Third, first fresh dialysis fluid/heating container or bag line or tube122needs to be located on the other side of peristaltic pump actuator30from patient line or tube124, so that peristaltic pump actuator30inFIGS.2and3may be rotated in the counterclockwise direction to pump heated, fresh dialysis fluid along first fresh dialysis fluid/heating container or bag line or tube122to patient P for filling. It should be appreciated that inFIGS.2and3, especially in a top loading configuration, where air mitigation is not as much of a factor, the relative positions of lines120and122versus lines124,126and128may be reversed, which would reverse the clockwise and counterclockwise directions just discussed.

FIG.3illustrates that disposable set100also includes a drain container or bag130connected to or in fluid communication with a distal end of drain line or tube120.FIG.2illustrates instead that drain line or tube120may extend to a house drain, e.g., toilet, sink or bathtub.FIGS.2and3illustrate that disposable set100also includes a first fresh dialysis fluid/heating container or bag132connected to or in fluid communication with a distal end of first fresh dialysis fluid/heating container or bag line or tube122.FIGS.2and3illustrate that disposable set100also includes a patient connector134connected to or in fluid communication with a distal end of patient line or tube124.FIGS.2and3further illustrate that disposable set100includes a second dialysis fluid container or bag136connected to or in fluid communication with a distal end of second dialysis fluid container or bag line126.FIGS.2and3illustrate that disposable set100still further includes a third dialysis fluid container or bag138connected to or in fluid communication with a distal end of third dialysis fluid container or bag line128.

First fresh dialysis fluid/heating container or bag132as illustrated inFIGS.2and3is placed onto batch heater34for heating and onto temperature sensors36aand36bfor temperature sensing. First fresh dialysis fluid/heating container or bag132may hold the same type and quantity of dialysis fluid as at least one of second and third containers or bags136,138. Alternatively, all three containers or bags may hold different types of dialysis fluids, e.g., different dextrose or glucose concentrations, and/or different quantities of same. Last container or bag138may for example hold a different formulation of dialysis fluid, e.g., icodextrin.

FIGS.2and3further illustrate drain line or tube120in operable communication with drain pinch valve40, first fresh dialysis fluid/heating container or bag line or tube122in operable communication with fluid/heater pinch valve42, patient line or tube124in operable communication with patient pinch valve44, second dialysis fluid container or bag line126in operable communication with second fluid valve46and third dialysis fluid container or bag line128in operable communication with third fluid valve48. Pinch valves40,42,44,46and48are alternatively stopcock valves as described herein.

FIGS.2and3illustrate that cycler20aof system10may provide additional sensors, such as air detection or prime sensors32aand32blocated along first fresh dialysis fluid/heating container or bag line or tube122and patient line or tube124, respectively. Air detection or prime sensors32aand32boutput to control unit50and may for example be light detection sensors, capacitance sensors, magnetic sensors or other types of sensors that can discern between air being present in the corresponding tube versus fresh or used dialysis fluid. Air detection sensor32aoperating with fresh dialysis fluid/heating container or bag line or tube122may be used for detecting air that comes out of solution during heating in first fresh dialysis fluid/heating container or bag132prior to delivery to patient P. Air detection or prime sensor32boperating with patient line or tube124may be used for confirming that the patient line has been primed properly and for air alarms during fresh dialysis fluid delivery to patient P.

Table 1 below illustrates one example valve sequencing chart for the flow schematic of system10ofFIG.3, under control of control unit50, in which valve42for first fresh dialysis fluid/heating container or bag line or tube122is located above valve40for drain line or tube120. It should be appreciated that the valve sequencing for system10inFIG.2, under control of control unit50, is the same as the chart below, wherein the difference is that the valves would read instead left to right V40, V42, V44, V48, V46. The first three sequences are for priming and involve flowing fresh dialysis fluid through different combinations of lines and in different directions to remove air from disposable set100. In priming sequence 1, control unit50causes drain valve40and dialysis fluid valves46and48to open and with the other valves closed actuates peristaltic pump actuator30in a clockwise direction (FIG.3) for a defined number of strokes to pull fresh dialysis fluid from second and third dialysis fluid containers or bags136,138to and to push same to drain130, priming lines or tubes126,128,108and120. In priming sequence 2, control unit50causes drain valve40and dialysis fluid valve46to open and with the other valves closed actuates peristaltic pump actuator30in a clockwise direction (FIG.3) for another defined number of strokes to pull fresh dialysis fluid from second dialysis fluid container or bag136and to push same to drain130, priming lines or tubes126,108and120.

In priming sequence 3, control unit50causes dialysis fluid/heater valve42and patient line valve44to open and with the other valves closed actuates peristaltic pump actuator30in a counterclockwise direction (FIG.3) for another defined number of strokes to pull fresh dialysis fluid from dialysis fluid/heater container or bag132and to push same to patient P, priming lines or tubes122,108and124. Along with the defined number of strokes (e.g., knowing patient line length and assumed volume pumped per stroke), or perhaps in place of the defined number of strokes, it is contemplated to position the end of patient line or tube124within a clip or other holder provided at housing22of cycler20a, and which is adjacent to air detection or prime sensor32b. When air detection or prime sensor32bsenses dialysis fluid instead of air, control unit50considers the priming of patient line or tube124to be complete or perhaps almost complete after which one or more additional pump stroke is made to ensure that the patient line is fully primed.

At the end of priming sequence 3, all lines of disposable set100have been primed. Priming sequences 1 to 3 also fully prime dialysis fluid chambers114of pressure sensing pods112aand112b. After priming, treatment may begin assuming that the fresh dialysis fluid within first fresh dialysis fluid/heating container132has been heated to body temperature. It is contemplated that the initial heating occur before and during priming sequences 1 to 3. Additionally, in many instances patient P is full of effluent at the start of treatment (from a prior treatment) so that after priming the first treatment step is a drain of patient P. The initial heating may accordingly also occur during an initial drain of patient P.

In the fill sequence of Table 1, control unit50causes dialysis fluid/heater valve42and patient line valve44to open (or remain open after priming sequence 3) and with the other valves closed actuates peristaltic pump actuator30in a counterclockwise direction (FIG.3) according to a fill profile in one embodiment. One possible fill profile starts with control unit50causing peristaltic pump actuator30to operate at a low positive pressure and flowrate and to ramp up the fill flowrate after a certain initial fill percentage has been completed to a maximum fill flowrate, e.g., set by the maximum allowable patient fill pressure, e.g., +1 psig to +9 psig (note that a higher psig limit, such as +9 psig may be restricted to certain points in the patient fill, e.g., during the middle portion). The flow profile may involve control unit50at the end of the patient fill lowering the positive pressure and flowrate, enabling a precise fill volume to be more easily achieved. It is believed that the patient is more sensitive to positive pumping pressure at the beginning and end of the patient fill, whereas the patient is less sensitive in the middle of the fill during which the patient's peritoneum is partially full and able to absorb higher pressures.

In the drain sequence of Table 1, control unit50causes drain valve40and patient line valve44to open and with the other valves closed actuates peristaltic pump actuator30in a clockwise direction (FIG.3) according to a drain profile in one embodiment. One possible drain profile is similar to the example fill profile and starts with control unit50causing peristaltic pump actuator30to operate at a low negative pressure and flowrate and to ramp up the drain flowrate after a certain initial drain percentage has been completed to a maximum drain flowrate, e.g., set by the maximum allowable patient drain pressure, e.g., −1 psig to −3 psig. The drain profile may involve control unit50at the end of the patient drain lessening the negative pressure and flowrate, enabling a precise drain volume to be more easily achieved. Alternatively, the drain may end when a particular condition occurs, e.g., a negative pressure sensing of the patient being empty or effectively empty. As before with filling, it is believed that the patient is more sensitive to negative pumping pressure at the beginning and end of the patient drain, whereas patient P is less sensitive in the middle of the drain where the patient's peritoneum is partially full of effluent, which is able to absorb higher negative pressures.

In the heater replenish sequence of Table 1, control unit50causes a desired one of the second or third dialysis fluid container valves46or48and first dialysis fluid/heater container valve42to be open, and with the other valves closed actuates peristaltic pump actuator30in a clockwise direction (FIG.3) for a defined number of strokes to pull fresh dialysis fluid from second or third dialysis fluid container or bag136,138and push same to dialysis first fluid/heater container or bag132. The defined number of strokes here may correspond to a subsequent patient fill volume, perhaps with some additional amount of fluid as an engineering factor and for tubing volume. It is contemplated that the heater replenish sequence occur directly after the completion of a patient fill and/or during a patient dwell to provide enough time for the fresh dialysis fluid replenish volume to be heated to body temperature, e.g., e.g., 37° C.

In addition to the valve sequencing discussed above in connection with Table 1, control unit50may further additionally be programmed to vary the speed of peristaltic pump actuator30to perform a patient fill according to a fill profile in which the speed of the peristaltic pump actuator operating in the filling direction is increased during a middle portion of the patient fill. Control unit50may still further additionally be programmed to perform a patient drain according to a drain profile in which the speed of peristaltic pump actuator30operating in the draining direction is increased during a middle portion of the patient drain. In any case, the peristaltic pumping system of the present disclosure provides a wide range of flowrates, e.g. from less than 10 mL/min to greater than 350 mL/min, while ensuring that positive and negative patient pressures are within limits. The peristaltic pumping is also relatively smooth due to pressure sensing pods112aand112bas discussed herein, allowing for minimal flow pulsation across treatment.

The priming sequence discussed in connection with Table 1 is for a valve arrangement in which there is independent control of each valve42to48.FIGS.2and3illustrate dashed boxes around valves40and42and valves44and46to show an alternative embodiment mentioned above in which the pinch valves are “3 by 2” pinch valves, which use a single motor and have two tubes running through the valve such that one tube is open while the other is closed, and wherein the states can be reversed. “3 by 2” pinch valves are incapable of opening or closing both tubes at the same time. The priming sequence using “3 by 2” pinch valves, e.g., in combination with a single pinch valve to provide five different line closures for the five lines120to128, may require a slightly different priming flowpath over the six sequences illustrated in Table 1. The overall result however is the same, which is a fully primed disposable set at the beginning of treatment.

Referring now toFIGS.4A and4B, rigid manifold110and pressure sensing pods112aand112bare illustrated in more detail.FIG.4Ais an exploded view showing the different components of pressure sensing pods112aand112b, wherein each component may be made of any of the materials discussed herein.FIG.4Aalso illustrates that pressure sensing pods112aand112bmay form a single rigid manifold110via bridging member110b. Pressure sensing pods112aand112bin the illustrated embodiment are made of three primary pieces, namely, a dialysis fluid chamber114that carries fresh or used dialysis fluid, a diaphragm116that flexes based on fluid pressure, and a transmission fluid chamber118that holds a pressure transmission fluid, such as air that is compressed corresponding to the positive or negative pumping pressure applied to the fresh or used dialysis fluid. The pressure transmission fluid contacts pressure transducers26and28that output corresponding pressure signals to control unit50. In one embodiment, dialysis fluid chambers114are sealingly fixed to transmission fluid chambers118, e.g., via ultrasonic sealing, heat sealing or adhesive sealing, in such a way that diaphragms116are sealed in place so that dialysis fluid is prevented from entering transmission fluid chambers118and transmission fluid is prevented from entering dialysis fluid chambers114.

In the illustrated embodiment, bridging member110bextends between dialysis fluid chambers114such that dialysis fluid chambers114of both pressure sensing pods112aand112bmay be made, e.g., molded, as a single unitary piece. Bridging member110bmay alternatively extend between transmission fluid chambers118such that the transmission fluid chambers may be made as a single unitary piece. Transmission fluid chambers118are each provided with a transmission fluid port118pthat may be configured to connect directly with one of pressure transducers26and28or to connect to the transducers via intermediary tubes (not illustrated).

FIGS.4A and4Billustrate that dialysis fluid chambers114of disposable set100are each provided with, e.g., formed with a peristaltic pumping port114p, which sealingly attaches to an end of peristaltic pumping tube108. Dialysis fluid chamber114of pressure sensing pod112aincludes tubing ports114aand114b, which sealingly attach to an end of drain line or tube120and first fresh dialysis fluid/heating container or bag line or tube122, respectively. Dialysis fluid chamber114of pressure sensing pod112bincludes tubing ports114c,114dand114ethat sealingly attach to an end of patient line or tube124, third dialysis fluid container or bag line128, and second dialysis fluid container or bag line126, respectively, in the illustrated embodiment, which corresponds to the tubing orientation ofFIG.2(versusFIG.3).

FIG.4Cillustrates one embodiment of an assembled pressure sensing pod112aor112b. Dialysis fluid chamber114of pressure sensing pod112aor112bincludes peristaltic tubing port114p, which sealingly attaches to an end of peristaltic pumping tube108. Dialysis fluid chamber114in the illustrated embodiment is ultrasonically, heat or adhesively sealed to transmission fluid chamber118in a manner so as to hold flexible diaphragm116sealingly in place. In the illustrated embodiment, dialysis fluid chamber114and transmission fluid chamber118include or define mating crimping rings CR that pinch flexible diaphragm116in a circular manner just inside of a thickened outer ring116rof flexible diaphragm116. Flexible diaphragm116as illustrated may be formed with one or more prestressed or preformed shapes, such as a preformed circular channel116c. Transmission fluid chamber118may likewise include or be formed with circular channel118cencircling transmission fluid port118p, wherein circular channel118cis aligned with circular channel116c

FIGS.5A and5Billustrate an alternative embodiment for disposable set100, which uses an alternative rigid manifold150, wherein dialysis fluid chambers114are modified to operate with stopcock handles140. Otherwise, diaphragms116, transmission fluid chambers118, the fixing of dialysis fluid chambers114to transmission fluid chambers118, and the arrangement of ports114ato114eand114pand their connection to tubes120,122,124,128,126and108are the same as described above forFIGS.4A and4Bin one embodiment. Stopcock handles140are driven by multiway or stopcock valve actuators, which are located within cycler20ain a manner similar to that illustrated for valves40,42,44,46and48, except that rigid manifold110is placed directly onto the multiway or stopcock valve actuators when loading disposable set100for treatment. Stopcock handles140include a driving aperture142that accepts a driving rod144(seeFIG.11A) of the stopcock valve actuators146and148(seeFIG.11A), e.g., via a keyed relationship. Control unit50causes the driving rods of the stopcock valve actuators to rotate to a desired angular position to allow fluid flow to or from a desired line or tube120,122,124,126or128.

For pressure sensing pod112a, control unit50causes the multiway or stopcock valve actuator to rotate stopcock handle140between three positions, one in which peristaltic pumping tube108communicates fluidly with drain line or tube120, another in which peristaltic pumping tube108communicates fluidly with first fresh dialysis fluid/heating container or bag line or tube122, and a third in which all lines are occluded. For pressure sensing pod112b, control unit50causes the multiway or stopcock valve actuator to rotate stopcock handle140between four positions, one in which peristaltic pumping tube108communicates fluidly with patient line or tube124, a second in which peristaltic pumping tube108communicates fluidly with second dialysis fluid container or bag line126, a third in which peristaltic pumping tube108communicates fluidly with third dialysis fluid container or bag line128, and a fourth in which all lines are occluded. The all lines occluded positions of the two stopcock valves enable flexible membranes116to be desirably positioned within chambers114and118so as to provide an accurate pressure signal over a desired range of positive and negative pressures to be measured.

It should be appreciated that there are other ways to actuate stopcock handles140besides the use of driving apertures142and mating driving rods. For example, the outer diameter of stopcock handle140may include gear teeth or ratchets that mate with gear teeth or ratchets of a driver that drives stopcock handle140from the outside.

Referring now toFIG.6, an alternative rigid manifold210of an alternative disposable set200for use with system10is illustrated. Alternative rigid manifold210includes four multiway or stopcock valves212ato212d(each having an all lines occluded position in one embodiment), which here are not integrated with pressure sensing pods112aand112b. It is accordingly contemplated for any version of system10to provided stopcock valves separately or in combination with pressure sensing pods112aand112b. Multiway or stopcock valves212ato212doperate with four respective multiway or stopcock valve actuators (not illustrated but part of the cycler) under control of control unit50. Stopcock valve212ais rotatable to allow fresh dialysis fluid to flow from manifold210into a heater inlet tube216aor from manifold210to drain tube120(to either a drain container or house drain). Stopcock valve212dis rotatable to allow fresh dialysis fluid to flow from either a second dialysis fluid dialysis fluid container line or tube126into manifold210or from a third dialysis fluid dialysis fluid container line or tube128into manifold210. Stopcock valve212bis rotatable to allow fresh dialysis fluid to flow from either a first dialysis fluid dialysis fluid container line or tube122into manifold210or from a fourth or last fill container line214into manifold210(disposable set200accordingly allows for an extra container of fresh dialysis fluid). Stopcock valve212cis rotatable to allow heated dialysis fluid to flow from a heater outlet tube216binto patient line124or used dialysis fluid to flow from patient line124into manifold210.

Alternative rigid manifold210also includes an inline fluid heating pathway220, e.g., serpentine, which is placed in operable communication with an inline heater (not illustrated) under control of control unit50, wherein the inline heater may be integrated with the cycler of system10or may be provided as a standalone unit as part of system10. In a standalone implementation, the standalone inline heater may include its own control unit, which may operate as a delegate control unit to cycler control unit50, wherein the two control units may communicate in a single direction or bidirectionally in a wired or wireless manner. One or more temperature sensor36aand36boutputting to control unit50may be provided for use as feedback to control the inline heater to output heated, fresh dialysis fluid into heater outlet tube216band patient line124at body temperature or 37° C. Control unit50may employ a proportional, integral, derivative (“PID”) control algorithm using feedback from one or more temperature sensor36aand36bto determine how much current or power to deliver to the inline heater.

Peristaltic pumping tube108is actuated via peristaltic pump actuator30under control of control unit50in a clockwise manner to pull used dialysis fluid from patient line124past pressure sensing pod112aand to push same past pressure sensing pod112b, and into drain line120to a drain container or house drain. Pressure sensing pods112aand112bdampen pulsatility and increase the accuracy of effluent or used dialysis fluid flow as discussed herein. Peristaltic pumping tube108is actuated via peristaltic pump actuator30under control of control unit50in a clockwise manner to pull fresh dialysis fluid from dialysis fluid container line122or fourth or last fill container line214past pressure sensing pod112aand to push same past pressure sensing pod112b, through inline heating pathway220where the fresh fluid is heated, and into patient line124to the patient. Pressure sensing pods112aand112bagain dampen pulsatility and increase the accuracy of fresh, heated dialysis fluid flow as discussed herein.

Peristaltic pumping tube108is actuated via peristaltic pump actuator30under control of control unit50in a counterclockwise manner to pull fresh dialysis fluid from second and third dialysis fluid container tubes or lines126and128past pressure sensing pod112band to push same past pressure sensing pod112aand into the first dialysis fluid container line or tube124in preparation for a next patient fill. The fill preparation movement of fresh dialysis fluid may be performed during a patient dwell. Pressure sensing pods112aand112bagain dampen pulsatility, however, because the patient is not involved in the fill preparation pumping procedure, the operating pressures and corresponding flowrates may be higher. System10ofFIG.6is further advantageous because, as discussed above, it allows for a fourth container of fresh dialysis fluid, which in addition to the last fill solution (e.g., icodextrin), may be the same or different type of fresh dialysis fluid as the first and second containers of dialysis fluid.

Referring now toFIG.7an alternative configuration for the cycler of system10is illustrated via cycler20b. Cycler20bis similar to cycler20aofFIG.1in that peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48are oriented such that pressure sensing pods112aand112band tubes or lines120to128of rigid manifold110are oriented horizontally. The primary difference is that peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48instead of being located within cycler20aas inFIG.1, are located instead on top of cycler20binFIG.7. A lightweight metal or plastic (e.g., clear acrylic) lid38may be provided, e.g., hinged to the housing of cycler20b, for easy access to peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48for the ready loading of disposable set100. While door or lid38does not have to be structurally capable of handling pinch valve forces, which is an advantage of cycler20b, door or lid38is however structurally sound enough to enable positioners provided by the lid to push disposable tubes or lines into respective pinch slots.

User interface58may be located along any desired surface of the housing of cycler20bor rotate up into position via a mounting arm hinged to cycler20b. Once disposable set100is loaded, lid38may be closed so that treatment may begin.

Another difference between cyclers20aand20bis that cycler20aincludes an integrated heater34. Cycler20binstead includes a standalone or modular heater (not illustrated), which may be a batch or inline heater. If a batch heater, initial dialysis fluid container or bag132disposable set100is loaded onto the batch heater for treatment. If an inline heater, inline fluid heating pathway220, e.g., serpentine, is loaded instead onto the inline heater for treatment. In either case, the standalone or modular heater enables cycler20bto be very compact, e.g., on the order of 214 mm (8.4 inches) and 175 mm (6.9 inches) in footprint by 110 mm (4.3 inches) in height, including lid38.

Referring now toFIGS.8A and8Banother alternative configuration for the cycler of system10is illustrated via cycler20c. Cycler20cis very similar to that of cycler20bofFIG.7in that peristaltic pump actuator30, pressure transducers26and28and the valve actuators are oriented such that pressure sensing pods112aand112band tubes or lines120to128of rigid manifold150are oriented horizontally. Another similarity is that peristaltic pump actuator30, pressure transducers26and28and the valve actuators are again located on top of cycler20cinFIG.7. A small, lightweight metal or plastic cover66may be provided, e.g., hinged, to the housing of cycler20c, for easy access to peristaltic pump actuator30, pressure transducers26and28and pressure sensing pods112aand112bfor the ready loading of rigid manifold150. User interface58in the illustrated embodiment rotates up into position via a mounting arm68hinged to cycler20b. Once disposable set100is loaded, cover66may be closed so that treatment may begin. For improved usability, it is contemplated for cover66to include or provide a moveable, e.g., slideable, peristaltic pump race to make the loading of pump tubing segment108easier. Cyclers20band20calso include a standalone or modular heater (not illustrated), which may be a batch or inline heater. If a batch heater, initial dialysis fluid container or bag132disposable set100is loaded onto the batch heater for treatment. If an inline heater, inline fluid heating pathway220, e.g., serpentine, is loaded instead onto the inline heater for treatment.

The primary difference between cycler20cand cycler20bis that instead of pinch valves, cycler20cuses the multiway or stopcock valve version of alternative rigid manifold150illustrated in connection withFIGS.5A and5B. To load alternative rigid manifold150, the user sets stopcock handles140(seeFIGS.5A and5B) onto multiway or stopcock valve actuators (seeFIG.11A), which are located at the top of cycler20c. The user then stretches peristaltic pumping tube108over peristaltic pump actuator30. Alternatively, control unit50may cause peristaltic pump actuator30to translate into operable position against peristaltic pumping tube108. In either case, the user then closes cover66over alternative rigid manifold150. Pressure sensing pods112aand112bassociated with stopcock handles140operate respectively with lines or tubes120and122and124,126and128as illustrated inFIGS.5B,8A and8B.

Referring now toFIG.9, a further alternative configuration for the cycler of system10is illustrated via cycler20d. Cycler20dis very similar to that of cycler20ain that peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48are oriented such that pressure sensing pods112aand112band tubes or lines120to128of rigid manifold110are oriented horizontally. Cyclers20dand20aalso each include an integrated batch heater34and associated temperature sensors36aand36bunder control of and outputting to control unit50. Batch heater34is oriented differently with cycler20d, which may help reduce the footprint of cycler20d. Batch, e.g., resistive, heater in any embodiment may be angled so that dialysis fluid container132is tilted to allow air to migrate up into the back of the container.

Cycler20dincludes a tray70onto which peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48are placed so such that disposable set100including pressure sensing pods112aand112band tubes or lines120to128of rigid manifold110may be loaded for treatment, after which tray70is translated into the housing of cycler20d. At the end of treatment, tray70is slideably opened to remove the used disposable set. While cycler20dis illustrated using pinch valves40to48, cycler20dmay alternatively use multiway or stopcock valves described herein.

Referring now toFIG.10, yet another alternative configuration for the cycler of system10is illustrated via cycler20e. Cycler20eis similar to that of cycler20din that cyclers20eand20dalso each include an integrated batch heater34and associated temperature sensors36aand36bunder control of and outputting to control unit50. Batch heater34is oriented the same as with cycler20d, which may help reduce the footprint of the cycler.

With cycler20e, peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48are oriented such that pressure sensing pods112aand112band associated tubes or lines120to128of rigid manifold110are oriented instead vertically. The vertical orientation may help with air mitigation. A vertically opened and closed door72, e.g., hinged to cycler20e, may be closed once disposable set100(not illustrated) is loaded vertically into operation with peristaltic pump actuator30, pressure transducers26and28and pinch valves40to48for treatment. Door72is opened when treatment is completed so that the used disposable set may be removed. While cycler20eis illustrated using pinch valves40to48, cycler20emay alternatively use multiway or stopcock valves described herein.

Referring now toFIGS.11A and11B, cycler20fillustrates an alternative vertically oriented disposable set embodiment using alternative stopcock rigid manifold150illustrated in connection withFIGS.5A and5B. Alternative stopcock rigid manifold150includes disposable stopcock handles140having driving apertures142that accept cycler driving rods144of stopcock valve actuators146and148under control of control unit50, e.g., via a keyed relationship. Control unit50causes driving rods144of the stopcock valve actuators146and148to rotate to a desired angular position to allow fluid flow to or from a desired line or tube120,122,124,126or128.

Cycler20fin the illustrated embodiment includes two doors, a horizontally hinged valve door74and a vertically hinged pump door76, which may be provided with a cutout78, e.g., circular cutout, which extends over pump peristaltic actuator30. To load stopcock rigid manifold150, the user opens doors74and76and places rigid stopcock manifold150onto valve door74so that pressure sensing pods112aand112bare seated in fitted pod seats (not illustrated) located on the inside of valve door74. The user then rotates door74up so that driving apertures142of stopcock handles140come into registry with driving rods144of stopcock valve actuators146and148. The valves of cycler20fare thereafter operational.

Rotating door74up (door74shown in phantom line inFIG.11Bto see pressure sensing pods112aand112bin solid line) also rotates peristaltic pumping tube108into close proximity to peristaltic pump actuator30. In one embodiment, the user then stretches peristaltic pumping tube108over peristaltic pump actuator30. Alternatively, control unit50may cause peristaltic pump actuator30to translate into operable position against peristaltic pumping tube108. In either case, once peristaltic pumping tube108is loaded for operation against peristaltic pump actuator30, the user closes pump door76, so that cutout78moves into registry with peristaltic pump actuator30. A further option is to provide a moveable raceway, e.g., as pump door76swings out or open, the raceway of the pump head moves accordingly to increase the clearance between the rollers of peristaltic pump actuator30and the raceway. As pump door76swings in or closes, the raceway closes onto the loaded peristaltic pumping tube108.

In an embodiment, cutout78is covered with glass or clear acrylic so that the rotation of peristaltic pump actuator30may be viewed but cannot be touched. Doors74and76as illustrated may overlap each other.

FIG.12illustrates a simplified version of system10, which includes drain container130and dialysis fluid containers or bags132,136and138and associated tubes or lines120,122,126and128leading respectively from or to peristaltic pumping tube108operating with peristaltic pump actuator30. Pressure sensing pods112aand112bare also illustrated. Patient line124leads from peristaltic pumping tube108to patient P. A flow sensor80is located along patient line124and outputs to control unit50. System10may also include a downstream patient pressure sensor112cthat outputs to control unit50.

Flow sensor80in an embodiment is an inline flow sensor, which may be an invasive disposable flow sensor or a reusable or durable flow sensor that is non-invasive. In either case, the output of flow sensor to control unit50may be integrated over time to monitor and determine accurately how much fresh dialysis fluid has been delivered to the patient and how much used dialysis fluid has been removed from the patient. Control unit50may also calculate a difference between the two, which is the patient's removed ultrafiltration (“UF”) volume. Flow sensor80is also used in connection with the charts below to output dialysis fluid flowrate. Thus while a goal of system10is to make peristaltic pumping inherently accurate, it is also contemplated to add a volume and flowrate monitoring and control device, such as a flow sensor80operating with control unit50.

FIG.12also illustrates that any of cyclers20ato20fof system10may optionally include a second peristaltic pump actuator30and associated peristaltic pumping tube108. The outlet pressure of the upstream peristaltic pump actuator30and associated peristaltic pumping tube108(depending on if flow is fresh dialysis fluid from left to right or used dialysis fluid from right to left) is used to set a desired positive pressure on the inlet side of the downstream peristaltic pump30/108. Doing so removes variability at the inlet side of the downstream peristaltic pump30/108and thus improves peristaltic pumping accuracy. That is, the serial placement of peristaltic pumps30/108ensures that the pressure boundary conditions of the downstream peristaltic pump30/108are consistent, which increases accuracy. Control unit50selects the revolutions per minute (“RPM”) of the upstream peristaltic pump30/108as a function of the RPM of the downstream peristaltic pump30/108in one embodiment. RPM's of the upstream peristaltic pump may be a (i) constant function, e.g., RPMupstream=f (RPMdownstream), where RPMdownstreamis determined by a set flowrate or a (ii) periodic function, e.g., RPMupstream=a sin(2πf*t)+b+RPMdownstream, where a is periodic function amplitude, f is frequency, and b is a constant offset.

FIG.13is a graph illustrating a positive pressure patient filling output according to any of peristaltic APD cyclers20ato20foperating with a disposable set100having pressure sensing pods112aand112b. Pressure sensing pods112aand112band associated system10of the present disclosure sense pressure and output signals as feedback to control unit50, which uses the feedback as part of an algorithm, e.g., a proportional, integral and derivative (“PID”) algorithm, to control the current to peristaltic pump actuator30so as to achieve a commanded pressure. ViewingFIGS.2and3it should be appreciated that pressure sensing pod112bmay be the pod associated with detecting positive and negative patient pumping pressure. Pressure sensing pod112amay be used for example to ensure that a higher system pressure limit, e.g., for pumping to fresh dialysis fluid/heating container or bag132, is not exceeded. Pressure sending pods112aand112bare also used by control unit50to detect partial or complete occlusion of any of the fluid lines120to128.

Pressure sensing pods112aand112balso provide an enlarged dialysis fluid volume bounded on one side by flexible membrane116, which dampens pressure pulses inherent with the actuation of peristaltic pump actuator30. The dampening of pressure spikes is important to reduce pulsatility and increase accuracy along with maintaining the dampened pressure output at or below a safe or comfortable patient limit.FIG.13illustrates that at a fill flowrate FR, e.g., using sensor80ofFIG.12, of about 280 m/min (which is typically more than adequate), pressure sensing pods112aand112benable a rather consistent positive patient pressure output PP below one psig to be simulated or determined, which is typically within a safe and comfortable range for patient P. InFIG.13, the positive pressure PP line representing the pressure at the patient is measured in a test rig. The other two sinusoidal pressure lines inFIG.13are from pressure sensing pods112aand112b, one on the negative pressure inlet side of pump actuator30and the other on the positive pressure outlet side of the pump actuator. A pressure drop occurs between the positive pressure outlet side of pump actuator30and the patient, which is predictable, and thus the outputs from pressure sensing pods112aand112bset a pressure band within which an accurate positive patient pressure may be calculated or determined at control unit50.FIG.13illustrates that at the very realistic flow of 280 mL/min or greater, the positive pressure PP at the patient is well within limit.

FIG.14is a graph illustrating a negative pressure patient drain output according to any of peristaltic APD cyclers20ato20foperating with a disposable set having pressure sensing pods112aand112b.FIG.14illustrates that at a drain flowrate FR, e.g., using sensor80ofFIG.12, of about 260 mL/min (which is likewise more than adequate), pressure sensing pods112aand112byield a rather consistent negative patient pressure output NP less than −1 psig, which is also typically within a safe and comfortable range for patient P. Like withFIG.13, inFIG.14, the negative pressure NP line representing the pressure at the patient is measured in a test rig. The other two sinusoidal pressure lines inFIG.13are from pressure sensing pods112aand112b, one on the negative pressure inlet side of pump actuator30and the other on the positive pressure outlet side of the pump actuator. A pressure drop occurs between the negative pressure inlet side of pump actuator30and the patient, which is predictable, and thus the outputs from pressure sensing pods112aand112bset a pressure band within which an accurate negative patient pressure may be calculated or determined at control unit50.FIG.14illustrates that at the very realistic flow of 260 mL/min or greater, the negative pressure PP at the patient is well within limit.

FIGS.13and14illustrate that system10performs well at higher flowrates needed to fill and drain the patient efficiently. It is also expected that typical APD treatments using system10may enter a slow flow condition, for example, during drain due to increased resistance induced in the patient's indwelling catheter caused by the catheter position inside the patient's peritoneal cavity and/or the catheter pores being partially blocked. The flowrate shown above in patient drainFIG.14may, for example, drop below 50 mL/min during slow flow and under the increased flow resistance. System10is nevertheless able to maintain accuracy and symmetry (fill versus drain accuracy) when there is no high resistance from patient catheter, e.g., over a range of flowrates, for example from 100 mL/min to greater 280 mL/min for patient filling and 15 mL/min to greater than 220 mL/min for patient draining and slow flow conditions. Thus, where it matters, when flowrates are higher, system10demonstrates more than sufficient accuracy.

System10accordingly by design commands a flowrate with speed and volume based on revolutions per minute (“RPM”) and by design expects pump actuator30to be accurate. Pressure pods112aand112bindicate if system10is experiencing a partial or full occlusion or a slow flow condition. If so, control unit50employs an algorithm to either lower the flowrate (RPM) to a predefined at least one level (e.g., one or two levels) and if the problem persists as determined by the algorithm, stops pump actuator30and alarms at user interface58to alert the patient to clear the occlusion or determine an empty condition. A goal of system10is however to transition from drain to fill without waking the patient, so that the algorithm may be programmed such that if the low flow condition occurs after a sufficient amount of effluent has been removed from the patient, then system10automatically transitions to a next patient fill unless treatment is completed at the end of the drain.

Control unit50of cyclers20ato20fof system10is in one embodiment configured to monitor the output pressure sensing pods112bduring a patient drain to look for a patient empty detection using a pressure monitoring algorithm. Control unit50is programmed to look for a characteristic increase in negative pressure drop (negative suction pressure increases) in patient line124at the end of a patient drain as measured by pressure sensing pod112b, wherein the characteristic increase in negative pressure at the end of drain (e.g., after a certain or threshold volume of effluent has been drained from patient P) indicates a patient empty condition. At that point, control unit50stops peristaltic pump actuator30from rotating in a draining direction (e.g., clockwise inFIGS.2and3) and switches the valves from a patient drain setting to a patient fill setting (see Table 1). Control unit50prior to halting the patient drain may attempt a pushback of effluent in patient line124to see if perhaps a blockage can be cleared, allowing further draining to occur. The pushback may be provided, for example, when control unit50, which counts peristaltic pump strokes and knows an average volume of fresh or used dialysis fluid moved per stroke, calculates that the drain volume is relatively low when the systematic decay in suction pressure is detected.

FIG.15illustrates a patient empty detection graph using any of cyclers20ato20fof system10. The upper line shows a drain flowrate FR, e.g., using sensor80ofFIG.12, while the lower line shows a negative pressure output NP using pressure sensing pods112aand112b.FIG.15also illustrates three example points along negative pressure output NP line, which are inputted into an algorithm used by control unit50to determine a patient empty condition. The first point occurs when control unit50determines that negative pressure output NP starts to increase or become more negative, e.g., after a certain number of readings all trend towards increased negative pressure. The second point occurs when control unit50determines that the negative pressure output NP increases or become more negative by a first delta amount from the first point, e.g., by −0.5 psig. The third point occurs when control unit50determines that negative pressure output NP increases or become more negative by a second delta amount from the first point, e.g., by −1.0 psig. Upon detecting the third point, control unit50in an example determines an end of drain condition and proceeds as described above. The output from flow sensor80may be used alternatively or additionally in an algorithm at control unit50to determine an end of drain, however, it is not expected that such a flow sensor is needed.

Control unit50of cyclers20ato20fof system10may also be programmed to detect a patient line occlusion based on a positive pressure rise (during filling) or a negative pressure rise (during draining) algorithm. A characteristic rise in suction pressure in patient line124measured by pressure sensing pod112bduring a patient drain indicates an occlusion to control unit50, while a characteristic rise in positive pressure in patient line124measured by pressure sensing pod112bduring a patient fill indicates an occlusion to control unit50. One or more fluid pushback attempt within patient line124may again be employed as part of the occlusion algorithms in an attempt to clear the occlusion and allow treatment to continue prior to alarming the patient.

FIG.16illustrates a full occlusion occurring during a patient drain using any of cyclers20ato20fof system10. The upper line shows a drain flowrate FR, e.g., using sensor80ofFIG.12, while the lower line shows a negative pressure output NP using pressure sensing pods112aand112b. At about three seconds, drain flowrate FR drops and negative pressure output NP increases due to a large occlusion. At about 4.4 seconds, control unit50using the occlusion detection algorithm of the present disclosure causes pump actuator30to stop and the drain flowrate FR to flatline to zero, while negative pressure output NP also flatlines to a high negative pressure, indicating a full occlusion. Here, pump actuator30stops based on the NP increase (and/or rate of change of NP increase) occurring at about three seconds. Once pump actuator30stops, if NP flatlines as is the case at about 4.4 seconds, the occlusion detection algorithm determines a full occlusion and causes user interface58to alarm. If instead the pressure changes to static pressure, the occlusion detection algorithm instead determines a partial occlusion. At about 7.4 seconds, the occlusion is released, e.g., via a fluid pushback, and drain flowrate FR increases, while negative pressure output NP decreases to a normal patient drain level. In one example, when the occlusion is released there is a momentary surge in flowrate due to a pressure differential between the two sides of the occlusion, the patient or bag side and the pump side (pump side pressure is lower). If a pushback is employed under complete occlusion, either the occlusion will release or the pressure will rise in the opposite direction as in the case of a fill occlusion. It is contemplated for control unit50to look for the occlusion change in one or both of pressure and flowrate as shown here at three and 4.4 seconds, and to attempt a pushback to clear the occlusion as shown here at 7.4 seconds. The same algorithm may be employed to look for and correct a partial patient drain occlusion.

FIG.17illustrates a full occlusion occurring during a patient fill using any of cyclers20ato20fof system10. The upper line shows a fill flowrate FR, e.g., using sensor80ofFIG.12, while the lower line shows a positive pressure output PP using pressure sensing pods112aand112b. At about 6.2 seconds, fill flowrate FR drops and positive pressure output PP increases due to a large occlusion. At about 7.6 seconds, control unit50using the occlusion detection algorithm of the present disclosure causes pump actuator30to stop and the fill flowrate FR to flatline to zero, while positive pressure output PP also flatlines to a high positive pressure, indicating a full occlusion. At about 10.4 seconds, the occlusion is released, e.g., via a fluid pushback, and drain flowrate FR increases, while positive pressure output PP decreases to a normal patient fill level. In one example, when the occlusion is released a momentary surge in flowrate occurs due to a pressure gradient between two sides of the occlusion, the pump outlet side and the patient side. It is contemplated for control unit50to look for the occlusion change in one or both of pressure and flowrate as shown here at 6.2 and 7.6 seconds, and to attempt a pushback to clear the occlusion as shown here at 10.4 seconds. The same algorithm may be employed to look for and correct a partial patient fill occlusion. The occlusion can either be released via a pushback from the cycler or be performed manually.

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 such changes and modifications be covered by the appended claims. For example, while system10may count peristaltic pump strokes and multiply the count by a known volume per stroke to calculate an overall volume of fresh ore used dialysis fluid pumped to or from a patient, system10may alternatively or additionally provide other volume monitoring and control techniques. Moreover, as discussed above, the integration of the output of an invasive or noninvasive flow sensor to control unit50may be used to determine an overall volume of fresh and used dialysis fluid pumped (and thus ultrafiltration (“UF”) removed from patient P). In another example, a weigh scale provided with heater34and a drain container (or separate fresh and used weigh scales), which outputs to control unit50is used to sense a weight loss associated with fresh dialysis fluid delivered to patient P and a weight gain associated with used dialysis fluid removed from patient P. Also, while inline heating is discussed inFIG.6being used with multiway or stopcock valves212ato212d, inline heating may be used instead with pinch valves.