Patent Application
20240066198
This application claims priority to and the benefit of Indian Provisional Patent Application No. 202141008530, entitled “Pod Pump Fluid Management System”, filed Mar. 1, 2021, the entire contents of which are incorporated herein by reference and relied upon.
The present disclosure relates generally to medical fluid treatments and in particular to dialysis fluid treatments.
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 dialysis 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 peritoneal chamber, 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.
In any of the above modalities using an automated machine, the automated machine operates typically with a disposable set, which is discarded after a single use. Depending on the complexity of the disposable set, the cost of using a set per day may become significant. Also, daily disposables require space for storage, which can become a nuisance for home owners and businesses. Moreover, daily disposable replacement requires daily setup time and effort by the patient or caregiver at home or at a clinic. There is also a need for APD devices to be portable so that a patient may bring his or her device on vacation or for work travel.
For each of the above reasons, it is desirable to provide a relatively simple, compact APD machine, which operates a simple and cost effective disposable set.
The present disclosure sets forth an automated peritoneal dialysis (“APD”) system having a machine or cycler that operates with a disposable set having a pod pump. In one possible configuration for the system, the disposable set includes multiple peritoneal dialysis fluid containers or bags, wherein one of the containers is placed on top of the cycler, which includes a heating plate to heat dialysis fluid located originally in the container as well as dialysis fluid pumped to the container from a second or later container for a subsequent patient fill. In an alternative embodiment, the plate or batch heater is replaced with an inline heater, which heats fresh dialysis fluid as it flows through the patient line to the patient. The disposable pumping pod or pod pump may be oriented vertically as illustrated herein, wherein fluid tubes or lines run horizontally from the pumping pod. An air pump for driving the disposable pod pump and other reusable components herein is located within a housing of the cycler.
The air pump is configured to provide both positive and negative pressure air to the disposable pod pump via a pneumatic valve manifold. The pneumatic valve manifold may include four pneumatic valves, including positive and negative pneumatic valves located between the air pump and the pod pump and reference chamber valves located between the pod pump and a reference chamber (located within the housing), wherein the reference chamber is used for fluid volume determinations discussed herein. In an embodiment, the air pump includes a box-in-a-box noise reducing structure in which inner and out noise reducing or attenuating encloses are provided about a pneumatic pump body to significantly reduce perceptible audible noise outputted by the air pump.
In an embodiment, a first pneumatic pressure sensor is located between the pneumatic valve manifold and the disposable pumping pod (pod pressure sensor). A second pneumatic pressure sensor is located between the pneumatic valve manifold and the reference chamber (reference pressure sensor). The pod and reference pressure sensors are used for the fluid volume determinations discussed herein. The pod pressure sensor is also used to control pumping pressure and to determine an end of stroke for the drawing and discharging of dialysis fluid into and from the pod pump.
The disposable set may include five fluid lines that extend from the disposable pumping pod, including a drain line that extends to a house drain (toilet, sink or bathtub) or to a drain bag. Three peritoneal dialysis fluid containers or bags are provided in one embodiment, one of which sits atop a batch heater as mentioned above. The fifth line is a patient line. The disposable pumping pod mounted vertically to the front or actuation surface of the dialysis cycler, allows the drain line to be located at the top of the pumping pod and the patient line to be located at the bottom of the pumping pod. Such arrangement allows for air in the pod pump to migrate naturally upwardly into the drain line where it can be pumped to drain.
Each of the five fluid lines is fitted into or operates with a pinch valve, which may be an electrically actuated solenoid valve. The pinch valves are failsafe in one embodiment, meaning that upon power loss the valves are biased to close their respective fluid lines. The pinch valves alternatively retain their state upon power loss, but are still part of a failsafe design in cooperation with the pod pump being deactivated upon power loss.
The pinch valves in an embodiment include a rotary nut motor that includes female threads that rotate threadingly around male threads of a threaded shaft. The female threads rotate and cause the threaded shaft to translate back and forth along a central axis extending through the threaded shaft. The rotary nut motor is bidirectional so that the threaded shaft, which carries a spring-loaded plunger in one embodiment, may cause a fluid line to be occluded or opened. A sensor, such as any type of object detecting sensor discussed herein, is provided to look for a proximal end of the threaded shaft protruding through the back of the pinch valve. If the proximal end is detected, indicating a valve open position, at a time when the valve is supposed to be occluding the fluid line, treatment is stopped and an alarm is provided in one embodiment.
The disposable set may include a drain line that is bifurcated into a smaller disposable portion and a longer, distal reusable portion. The disposable and reusable portions are separated by a reusable drip chamber that breaks the effluent drain flow so as to create an air column in a top portion of the drip chamber. The air column prevents any pathogens that develop in the reusable portion of the drain line from traveling through the effluent into the smaller disposable portion of the drain line. The longer, distal reusable portion of the drain line reduces disposable cost and waste.
The drip chamber may include a sensing portion within which the air column is formed and maintained. The sensing portion may include a window or slot for operation with one or more sensor provided by the cycler, e.g., a pair optical sensors. The sensors detect whether air or liquid (effluent) is present. The lower sensor detecting effluent instead of the air column may cause the cycler to take an evasive action, e.g., slow down or stop the present drain flow, while an upper sensor detecting effluent instead of the air column may cause the cycler to take more sever actions, e.g., stop treatment and notify the patient to look for a kink or occlusion in the reusable drain line.
The drip chamber may also be provided with a port for connection to an air pump that pumps into the sensing portion to help maintain the air column or for connection to an air tube having a distal hydrophobic vent that allows air into the sensing portion under negative pressure to help maintain the air column. Positive pressure air may also be used at the end of a patient drain phase to blow out the reusable drain line to prevent or mitigate pathogen growth. To this end, the drip chamber may also be provided with a disinfectant well or sponge to prevent pathogen migration up an inner wall of the sensing portion and for contacting effluent that rises too high in the sensing portion of the drip chamber.
The drip chamber and reusable drain line may be provided with a cycler having the pneumatic pod pumping discussed herein but may alternatively be provided with a cycler having a different type of pumping, such as a durable PD fluid contacting pump that is disinfected after treatment instead of being discarded. In any case, the drip chamber and the reusable portion of the drain line may be capped after treatment when the disposable portion of the drain line has been removed. For example, a distal end of the reusable portion of the drain line may be provided with a tethered cap for capping the distal end, or the cycler may be provided with a blind port for receiving the distal end of the reusable portion of the drain line.
For priming, it is contemplated that the cycler provide a prime sensor/bubble detector, e.g., an optical or capacitive sensor, which operates with the patient line to look for (i) fluid during priming to know that the patient line has been fully primed and (ii) air during treatment. If air is detected during treatment, the air entrained dialysis fluid may be pulled back into the disposable pumping pod and then pumped out to drain.
The pod pump may be constructed in multiple ways. In one embodiment the pod pump includes a rigid, e.g., plastic disposable shell and a flexible sheet, diaphragm or membrane fixed, e.g., ultrasonically welded, to the shell. Here, positive and negative pneumatic pressure is supplied from the air pump and the pneumatic valve manifold to the flexible sheet, diaphragm or membrane. In another embodiment, the pod pump includes two rigid plastic shells, namely, a pneumatic rigid plastic shell and a fluid contacting rigid plastic shell, which are sealed together to hold a flexible sheet, diaphragm or membrane in a sealed manner therebetween. A central pneumatic port is provided in the pneumatic rigid shell, which communicates pneumatically with the air pump and the pneumatic valve manifold. Here, air resides between the rigid plastic shell having the pneumatic port and the flexible membrane. In either of the above embodiments, five fluid ports extend from the fluid contacting rigid plastic shell, which connect to the five fluid lines discussed above. Fresh, fresh heated, or used dialysis fluid resides accordingly between the fluid contacting rigid plastic shell and the flexible membrane. In either embodiment, the flexible membrane is (i) pulled towards the actuation surface under negative pressure to pull fresh or used dialysis fluid into the disposable pumping pod, and (ii) pushed away from the actuation surface under positive pressure to push fresh or used dialysis fluid from the disposable pumping pod.
The pod pump, the flexible plastic sheet, 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. As illustrated herein, the housing of the cycler may take different forms, e.g., the user interface may rotate up or out from the housing or may be integrated with the housing. A lid of the housing may be provided in halves that rotate outwardly to accept portions of a dialysis fluid/heater container or bag. Such arrangement allows an overall size and footprint to be smaller and to not be constrained at least in two dimensions by the size of the fluid/heater container or bag.
A control unit having one or more processor, one or more memory and a video controller operating with a user interface is provided to control each of the fluid valves, each of the pneumatic valves, the air pump, and the heater and to receive signals from each of the pressure sensors, the priming sensor or air detector, and one or more temperature sensor associated with the batch or inline the 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 is also programmed to perform calculations based on the ideal gas law to determine how much fresh or used dialysis fluid has been pumped by the pod pump.
In one embodiment, the control unit is programmed to cause fresh or used dialysis fluid to be drawn into the pod pump using the following procedure. Here, the air pump is configured to be in a negative pressure or suction mode and is placed in pneumatic communication with the disposable pod pump via the opening of the negative pneumatic valve located between the air pump and the pod pump. A desired fluid source valve from which fluid is to be drawn into the disposable pumping pod is opened, e.g., a fresh dialysis fluid source valve, the heater bag valve or the patient valve. The control unit uses pressure feedback from the pod pressure sensor in an algorithm, e.g., a proportional, integral, derivative (“PID”) routine, to regulate the air pump to maintain a desired negative fluid pressure while fluid is pulled into the disposable pumping pod. In an embodiment, the control unit controls current to the air pump to adjust its speed and thus its negative pneumatic pressure output. The desired pressure may be different depending on the fluid source, e.g., −1.5 psig to −3.0 psig for pulling effluent from the patient or higher for pulling fresh PD fluid from a dialysis fluid container.
The control unit in one embodiment uses a second algorithm to sense a spike in negative pressure and/or a corresponding drop in air pump speed to indicate an end of stroke and that the pod pump is filled with fresh or used dialysis fluid, which causes a trigger to stop the air pump.
In one embodiment, the control unit is programmed to measure an initial volume of fresh or used dialysis fluid drawn between the flexible sheet and the fluid contacting rigid plastic shell using two sets of pressure measurements and the ideal gas law. In a first set of pressure measurements, the control unit takes the pressure measurements of (i) the air side of the disposable pumping pod using the pod pressure sensor and (ii) the reference chamber using the reference pressure sensor. After fresh or used dialysis fluid is drawn into the pod pump, the control unit in a second set of pressure measurements opens one or more pneumatic valve(s) to allow the air side of the disposable pumping pod and the reference chamber to communicate pneumatically. Here, both the pod and reference pressure sensors measure the pressure of the combined cavity. Then, with all values on the right side of the following equation known or measured (the volume of the reference chamber is known), the control unit calculates the volume of fluid pulled into the disposable pumping pod is as follows:
V
fluid initial
=V
reference chamber*(Pref final−Pref initial)/(Ppump initial−Ppump final)
In one embodiment, the control unit is programmed to cause fresh or used dialysis fluid to be pumped from the pod pump using the following procedure. Here, the air pump is configured to be in a positive pressure mode, which is placed in pneumatic communication with the disposable pumping pod via the opening of the positive pneumatic valve located between the air pump and the pod pump. A desired fluid destination valve through which fluid is to be delivered from the disposable pumping pod is opened, e.g., the heater bag valve, the patient valve or the drain valve. The control unit uses pressure feedback from the pod pressure sensor in the pressure algorithm, e.g., PID routine, to regulate the air pump to maintain a desired positive fluid pressure while fluid is discharged from the disposable pumping pod. Again, the control unit controls current to the air pump to adjust its speed and thus its positive pneumatic pressure output. The desired pressure may be different depending on the fluid destination, e.g., 3.0 psig to 8.0 psig for pushing fresh, heated dialysis fluid to the patient or higher for pushing to drain or the heating container. The control unit in one embodiment uses an additional algorithm to sense a spike in positive pressure and/or a corresponding drop in air pump speed to indicate an end of stroke and that the pod pump has been emptied of fresh or used dialysis fluid, which causes a trigger to stop the air pump.
In one embodiment, the control unit is programmed to measure a final volume of fresh or used dialysis fluid located between the flexible sheet and the fluid contacting rigid plastic shell using the same two sets of pressure measurements and the ideal gas law. In a first set of pressure measurements, the control unit takes the pressure measurements of (i) the air side of the disposable pumping pod using the pod pressure sensor and (ii) the reference chamber using the reference pressure sensor. After fresh or used dialysis fluid is pumped from the pod pump, the control unit in a second set of pressure measurements opens one or more pneumatic valve(s) to allow the air side of the disposable pumping pod and the reference chamber to communicate pneumatically. Here, both the pod and reference pressure sensors measure the pressure of the combined cavity. Then, with all values on the right side of the following equation known or measured, the control unit calculates the volume of fluid remaining in the pumping pod after the discharge stroke as follows:
V
fluid final
=V
reference chamber*(Pref final−Pref initial)/(Ppump initial−Ppump final)
The control unit then calculates the volume of fluid pumped from the pod pump by calculating the difference between the calculated pumping chamber volume before (Vfluid initial) and after (Vfluid final) pumping. The above steps or procedures are repeated until a required or prescribed volume of fresh or used dialysis fluid is pumped. The same pumping regime just described is used to pump fluid from any fluid source to any destination.
In light of the disclosure set forth herein, and without limiting the disclosure in any way, in a first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis system comprises a cycler including a pneumatic valve manifold, an air pump positioned and arranged to supply pneumatic pressure to the pneumatic valve manifold without intervening pneumatic storage, a pneumatic pressure sensor positioned and arranged to detect pneumatic pressure, and a control unit configured to use an output of the pneumatic pressure sensor as feedback to adjust the air pump according to a set pneumatic pressure; and a disposable set including a pod pump having a flexible sheet, one side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure via the air pump and pneumatic valve manifold.
In a second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the air pump is configured to supply positive and negative pneumatic pressure.
In a third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pneumatic valve manifold includes a positive pneumatic valve positioned between the air pump and the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure and a negative pneumatic valve positioned between the air pump and the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure, and wherein the control unit is configured to open the positive pneumatic valve when the air pump is supplying positive pneumatic pressure and to open the negative pneumatic valve when the air pump is supplying negative pneumatic pressure.
In a fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pneumatic valve manifold further includes at least one additional pneumatic valve positioned and arranged to allow a reference chamber to communicate pneumatically with the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure.
In a fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pressure sensor is a first pressure sensor positioned and is arranged between the pneumatic valve manifold and the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure, and wherein the cycler also includes a second pressure sensor positioned and arranged between the pneumatic valve manifold and the reference chamber.
In a sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to use outputs from the first and second pressure sensors in combination with a sequence of the positive pneumatic valve, negative pneumatic valve and the at least one additional pneumatic valve and an ideal gas law equation to compute at least one of (i) an initial dialysis fluid volume in the pod pump after fresh or used dialysis fluid is drawn into the pod pump or (ii) a final dialysis fluid volume in the pod pump after fresh or used dialysis fluid is pumped from the pod pump.
In a seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to subtract (ii) from (i) to determine a volume of the fresh or used dialysis fluid pumped from the pod pump.
In an eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to use at least one of a sensed speed of the air pump or the output of the pneumatic pressure sensor to determine that the flexible sheet has completed (i) drawing fresh or used dialysis fluid into the pod pump or (ii) pumping fresh or used dialysis fluid from the pod pump.
In a ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the cycler further includes at least one of (i) a batch or inline dialysis fluid heater under control of the control unit or (ii) an air or priming sensor outputting to the control unit.
In a tenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the cycler further includes an actuation surface, and wherein the one side of the flexible sheet is positioned and arranged during operation to receive pneumatic pressure through the actuation surface via the air pump and pneumatic valve manifold.
In an eleventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the disposable cassette includes a plurality of dialysis fluid lines extending from the pod pump, wherein the cycler includes a plurality of fluid valves provided along the actuation surface for interfacing with the plurality of dialysis fluid lines, and wherein the fluid valves are optionally spring actuated to occlude the plurality of dialysis fluid lines.
In a twelfth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the disposable cassette includes a fluid contacting rigid plastic shell, wherein the flexible sheet is fixed to the fluid contacting rigid plastic shell.
In a thirteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the disposable cassette includes a pneumatic rigid plastic shell and a fluid contacting rigid plastic shell, which are sealed together to hold the flexible sheet therebetween.
In a fourteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the air pump is provided within a noise-reducing enclosure.
In a fifteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis system comprises a disposable set including a pod pump having a flexible sheet, one side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure; and a cycler including a pneumatic valve manifold for providing pneumatic pressure to the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure, an air pump positioned and arranged to supply pneumatic pressure to the pneumatic valve manifold without intervening pneumatic storage, a reference chamber in pneumatic communication with the pneumatic valve manifold, a first pneumatic pressure sensor positioned and arranged to detect pneumatic pressure outputted by the air pump, a second pressure sensor positioned and arranged to detect pneumatic pressure within the reference chamber, and a control unit configured to use outputs from the first and second pressure sensors in combination with a sequence of the pneumatic valve manifold and an ideal gas law equation to compute at least one of (i) an initial dialysis fluid volume in the pod pump after fresh or used dialysis fluid is drawn into the pod pump or (ii) a final dialysis fluid volume in the pod pump after fresh or used dialysis fluid is pumped from the pod pump.
In a sixteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to subtract (ii) from (i) to determine a volume of the fresh or used dialysis fluid pumped from the pod pump.
In a seventeenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is further configured to repeat (i) and (ii) and to subtract (ii) from (i) until a prescribed volume of fresh or used dialysis fluid is pumped.
In an eighteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pneumatic valve manifold includes a positive pneumatic valve positioned between the air pump and the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure and a negative pneumatic valve positioned between the air pump and the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure, and at least one additional pneumatic valve positioned and arranged to allow the reference chamber to communicate pneumatically with the side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure, and wherein the control unit is configured to use outputs from the first and second pressure sensors prior to and after the at least one additional pneumatic valve is opened.
In a nineteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sequence of the pneumatic valve manifold includes opening the negative pneumatic valve to draw fresh or used dialysis fluid into the pod pump prior to opening the at least one additional pneumatic valve.
In a twentieth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sequence of the pneumatic valve manifold includes opening the positive pneumatic valve to pump fresh or used dialysis fluid from the pod pump prior to opening the at least one additional pneumatic valve.
In a twenty-first second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to open the positive pneumatic valve when the air pump is supplying positive pneumatic pressure and to open the negative pneumatic valve when the air pump is supplying negative pneumatic pressure.
In a twenty-second second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis system comprises a cycler including a dialysis fluid pump, a plurality of valve actuators, and a control unit configured to control the dialysis fluid pump and the plurality of valve actuators; and a disposable set including a pump actuation portion operable with the dialysis fluid pump, a valve actuation portion operable with the plurality of valve actuators and a drain line, the drain line including a disposable portion, a reusable portion, and a drip chamber located between the disposable portion and the reusable portion, the drip chamber configured to create an air column that dissuades pathogen migration from the reusable portion to the disposable portion.
In a twenty-third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the drip chamber is reusable and provided with the reusable portion of the drain line.
In a twenty-fourth second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the dialysis fluid pump includes a pneumatic valve manifold and an air pump positioned and arranged to supply pneumatic pressure to the pneumatic valve manifold.
In a twenty-fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pump actuation portion of the disposable set includes a pod pump having a flexible sheet, one side of the flexible sheet positioned and arranged during operation to receive pneumatic pressure via the air pump and pneumatic valve manifold.
In a twenty-sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the plurality of valve actuators include pinch valve actuators.
In a twenty-seventh second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the valve actuation portion of the disposable set includes a plurality of lines, including the drain line, positioned and arranged to be actuated by the pinch valve actuators
In a twenty-eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system includes a pneumatic pressure sensor positioned and arranged to detect pneumatic pressure, and a control unit configured to use an output of the pneumatic pressure sensor as feedback to adjust the air pump according to a set pneumatic pressure.
In a twenty-ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the reusable portion of the drain line is longer than the disposable portion of the drain line.
In a thirtieth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system includes a connector located at an end of the disposable portion of the drain line, the connector configured to connect to the drip chamber, the connector configured to dissuade touch contamination.
In a thirty-first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the cycler includes a clip for holding the drip chamber.
In a thirty-second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the cycler includes a sensor outputting to the control unit, the drip chamber positioned and arranged to enable the sensor to sense the air column.
In a thirty-third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sensor is an optical sensor, an ultrasonic sensor, a capacitance sensor, a proximity sensor, a magnetic sensor or combinations thereof.
In a thirty-fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sensor incudes first and second sensors spaced elevationally apart, the control unit programmed to react differently to the first sensor versus the second sensor detecting an interruption of the air column.
In a thirty-fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the drip chamber includes a window or slot for operation with the sensor.
In a thirty-sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the drip chamber includes a well configured to receive and hold disinfectant.
In a thirty-seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system includes a disinfectant reservoir positioned and arranged to deliver disinfectant to the well.
In a thirty-eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system includes a disinfectant sponge configured for insertion into the drip chamber.
In a thirty-ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the disinfectant sponge is provided as part of the disposable portion of the drain line.
In a fortieth first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the drip chamber includes a port connectable to a pneumatic line for receiving air to help maintain the air column.
In a forty-first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system includes an air pump for delivering air through the pneumatic line or a hydrophobic vent placed at a distal end of the pneumatic line enabling air to be drawn into the drip chamber under negative pressure.
In a forty-second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a pinch valve includes a linear actuator; a shaft driven be the linear actuator; a plunger moved by the shaft; a housing defining an aperture through which the plunger extends to occlude a fluid line; and a sensor positioned and arranged relative to the linear actuator so as to sense a portion of the shaft indicating a valve open position.
In a forty-third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the housing is fixed to the linear actuator.
In a forty-fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the shaft is a threaded shaft and the linear actuator includes a rotary nut motor threadingly engaged to the threaded shaft for translating the threaded shaft in a first direction when the rotary nut motor rotates in a first direction and translating the threaded shaft in a second direction when the rotary nut motor rotates in a second direction.
In a forty-fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the pinch valve includes a collar coupled to the shaft, a mounting flange fixed to the plunger, and a spring positioned between the plunger and the collar, the spring biased to pull the mounting flange against the collar when the plunger does not engage the fluid line, the spring configured to be compressed when the plunger engages the fluid line.
In a forty-sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sensor is mounted to the linear actuator.
In a forty-seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sensor is positioned and arranged to sense a proximal end of the shaft extending though a back of the linear actuator.
In a forty-eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sensor is an optical, capacitive, or ultrasonic sensor.
In a forty-ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system a sealing mechanism for sealing a distal end of the disposable portion of the drain line after treatment.
In a fiftieth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the sealing mechanism includes a tethered cap or a blind port provided at the cycler.
In a fifty-first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the peritoneal dialysis system (i) includes a sealing mechanism for sealing the drip chamber after treatment or (ii) is configured such that the disposable portion of the drain line remains connected to the drip chamber after treatment.
In a fifty-second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, any of the features, functionality and alternatives described in connection with any one or more of
In light of the above aspects and present disclosure, it is an advantage of the present disclosure to provide a relatively volumetrically accurate automated peritoneal dialysis (“APD”) cycler.
It is another advantage of the present disclosure to provide an APD cycler that achieves relatively precise pressure control.
It is a further advantage of the present disclosure to provide a relatively quiet APD cycler.
It is still another advantage of the present disclosure to provide a pneumatically operated APD cycler that does not require pressure storage devices.
It is still a further advantage of the present disclosure to provide an APD system that is able to build motive fluid or pneumatic pressure in a relatively simple manner.
It is yet another advantage of the present disclosure to provide an APD system that employs a relatively low cost disposable set.
It is yet a further advantage of the present disclosure to provide an APD system that employs a primarily reusable drain line, which saves disposable cost.
Still another advantage of the present disclosure is to provide an APD system that employs improved pinch valves.
Still a further advantage of the present disclosure is to provide an APD system that employs a reduced noise air pump.
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.
Referring now to the drawings and in particular to
As illustrated in
In one possible configuration for system 10 as illustrated in
Disposable pumping pod or pod pump 110 is oriented vertically in the illustrated embodiment of
Disposable set 100a may alternatively provide more or less than the illustrated five fluid lines, e.g., the number of fresh dialysis fluid containers may be varied. Fresh dialysis fluid containers 102a to 102c may contain the same or different types and volumes of fresh dialysis fluids. For example, fresh dialysis fluid containers 102a to 102c may contain different levels of dextrose or glucose. One of the containers may contain a different formulation of fresh dialysis fluid, e.g., icodextrin, for a patient's last fill.
With disposable set 100a and pumping pod 110 mounted vertically to actuation surface 24 of cycler 20a, drain line 104 is located at the top of the pumping pod, while patient line 18 is located at the bottom of the pumping pod. Such arrangement allows for air in pod pump 110 to migrate naturally upwardly into drain line 104 where it can be pumped to the house drain or drain container.
To load disposable set 100a and pod pump 110, the patient or user in one embodiment opens door 26 as illustrated in
Referring additionally to
In the illustrated embodiment, air pump 40 delivers both positive and negative pressure air to disposable pod pump 110 via a pneumatic valve manifold 50. In particular, positive pressure line 42 leads from positive port 40a to pneumatic valve manifold 50, while negative pressure line 44 leads from negative port 40b to pneumatic valve manifold 50. Pneumatic valve manifold 50 in the illustrated embodiment includes four pneumatic valves, including positive and negative pneumatic valves 52a and 52b located between air pump 40 and pod pump 110, and reference chamber valves 54a and 54b located between pod pump 110 and a known volume reference chamber 60, which is used for fluid volume determinations discussed herein. Pneumatic valves 52a, 52b, 54a and 54b in an embodiment are electrically actuated solenoid valves that open upon being energized so as to operate in a failsafe way. Pneumatic valve manifold 50 also includes pneumatic lines 56 linking positive and negative pneumatic valves 52a and 52b and reference chamber valves 54a and 54b. In an embodiment, one of reference chamber valves 54a and 54b pneumatically connects reference chamber 60 to pneumatic rigid plastic shell 120 when needed, while the other of reference chamber valves 54a and 54b pneumatically connects reference chamber 60 to ambient for venting the reference chamber when needed.
In the illustrated embodiment, a first pneumatic pressure sensor 48a is located between pneumatic valve manifold 50 and disposable pumping pod 110 (pod pressure sensor). A second pneumatic pressure sensor 48b is located between pneumatic valve manifold 50 and reference chamber 60 (reference pressure sensor). Pod and reference pressure sensors 48a and 48b are used for the volume determinations discussed herein. Pod pressure sensor 48a is also used to control the pumping pressure of pod pump 110 and to determine an end of stroke for the drawing and discharging of fresh and used dialysis fluid into and from the pod pump. Pod pressure sensor 48a enables system 10 to not provide a pressure sensor located along patient line 108, however, such a patient line pressure sensor may be provided if desired, e.g., for redundancy. Reference pressure sensor 48b is located along a pneumatic loop 62 pneumatically linking pneumatic valve manifold 50 to reference chamber 60.
As illustrated in
For priming, it is contemplated that cycler 20a provide a prime sensor/bubble detector 58, e.g., an optical or capacitive sensor, which operates with patient line 108 to look for (i) fresh dialysis fluid during priming to know that patient line 108 has been fully primed and (ii) air in patient line 108 during treatment. If air is detected during treatment, the air entrained dialysis fluid may be pulled back along patient line 108 into disposable pumping pod 110, and then pumped out to drain via drain line 104. Alternatively, it is contemplated to allow a certain amount of air to build within pod pump 110, e.g., at the top of the fluid contacting shell 114, before being delivered to drain.
In either of the pod pump 120 embodiments of
Rigid shells 114 and 120 and flexible plastic sheet 112 of pod pump 110, fluid lines 104, 106a to 106c and 108 and fluid containers 102a to 102c of disposable set 100a 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”). Housing 22a of cycler 20a may be made of any of the above plastics, and/or of metal, e.g., stainless steel, steel and/or aluminum.
User interface 88 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.
In one embodiment, control unit 80 is programmed to cause fresh or used dialysis fluid to be drawn into pod pump 110 using the following procedure. Air pump 40 is configured to be in a negative pressure or suction mode and is placed in pneumatic communication with disposable pod pump 110 via the opening of negative pneumatic valve 52b of pneumatic valve manifold 50. A desired fluid source valve from which fluid is to be drawn into the disposable pumping pod is opened, e.g., dialysis fluid valves 36a to 36c or patient valve 38. Control unit 80 uses pressure feedback from the pod pressure sensor 48 in an algorithm, e.g., a proportional, integral, derivative (“PID”) routine, to regulate air pump 40 to maintain a desired or set negative fluid pressure while fresh or used dialysis fluid is pulled into disposable pumping pod 110. In an embodiment, control unit 80 controls electrical current to air pump 40 to adjust its speed and thus its negative pneumatic pressure output. The desired or set pressure may be different depending on the fluid source, e.g., −1.5 psig to −3.0 psig for pulling from patient P or higher negative pressure for pulling fluid from a dialysis fluid container.
Control unit 80 in one embodiment uses a second algorithm to sense a spike in negative pressure from pod pressure sensor 48a and/or a corresponding drop in the speed of air pump 40 to indicate an end of stroke and that pod pump 110 is filled with fresh or used dialysis fluid, which causes a trigger to stop air pump 40. The speed of air pump 40 is measureable, e.g., via monitoring a moving part of the air pump such as a piston, membrane or shaft rotation speed, and wherein the measured speed is proportional to dialysis fluid filling flowrate. Alternatively or additionally, the speed of air pump 40 may be known or assumed from a speed commanded by control unit 80.
In one embodiment, control unit 80 is programmed to cause fresh or used dialysis fluid to be pumped from pod pump 110 using the following procedure. Air pump 40 is configured to be in a positive pressure mode, which is placed in pneumatic communication with disposable pumping pod 110 via the opening of positive pneumatic valve 52a of pneumatic valve manifold 50. A desired fluid destination valve through which fluid is to be delivered from the disposable pumping pod is opened, e.g., drain valve 34, dialysis fluid heater valves 36a or patient valve 38. Control unit 80 uses pressure feedback from pod pressure sensor 48a in the pressure algorithm, e.g., PID routine, to regulate air pump 40 to maintain a desired or set positive fluid pressure while fluid is discharged from disposable pumping pod 110. Again, control unit 80 may control electrical current to air pump 40 to adjust its speed and thus its positive pneumatic pressure output. The desired or set pressure may be different depending on the fluid destination, e.g., 3.0 psig to 8.0 psig for pushing fresh, heated dialysis fluid to patient P or higher positive pressure for pushing fluid to drain or the heating container 102a.
Control unit 80 in one embodiment uses an additional algorithm to sense a spike in positive pressure from pod pressure sensor 48a and/or a corresponding drop in the speed of air pump 40 to indicate an end of stroke and that pod pump 110 has been emptied of fresh or used dialysis fluid, which causes a trigger to stop air pump 40. The speed of air pump 40 is measureable as discussed above, e.g., via monitoring a moving part of the air pump such as a piston, membrane or shaft rotation speed, and wherein the measured speed is proportional to dialysis fluid emptying flowrate. Alternatively or additionally, the speed of air pump 40 may be known or assumed from a speed commanded by control unit 80.
Control unit 80 is programmed to employ a method 150 for determining how much fresh or used dialysis fluid has been delivered from pod pump 110. In method 150, control unit 80 measures an initial volume of fresh or used dialysis fluid drawn between flexible sheet 112 and the fluid contacting rigid plastic shell 114 using two sets of pressure measurements and an equation based on the ideal gas law. At oval 152, method 150 begins. At block 154, control unit 80 opens negative pneumatic valve 52b, opens a desired source pinch valve 36a to 36c or 38 and runs air pump 40 so as to create a desired negative pumping pressure and draw fresh or used dialysis fluid into pod pump 110.
At block 156, in a first set of pressure measurements, control unit 80 takes pressure measurements of (i) the air side of the disposable pumping pod 110 using pod pressure sensor 48a and (ii) reference chamber 60 using reference pressure sensor 48b.
At block 158, in a second set of pressure measurements, control unit 80 opens one or more pneumatic reference valve(s) 54a and/or 54b to allow the air side of disposable pumping pod 110 and reference chamber 60 to communicate pneumatically. Here, both pod pressure sensor 48a and reference pressure sensor 48b measure the pressure of the combined pneumatic cavity. The difference between the first set of measurements at block 156 and the second set of measurements at block 158 is that the first pressure readings at block 156 are taken before pneumatically connecting pumping pod 110 and reference chamber 60, while the second pressure readings at block 158 are taken after pneumatically connecting pumping pod 110 and reference chamber 60.
At block 160, with all values on the right side of the following equation (based on the ideal gas law) known or measured, including the known volume of reference chamber 60, control unit 80 calculates the volume of fresh or used dialysis fluid pulled into disposable pumping pod 110 is as follows:
V
fluid initial
=V
reference chamber*(Pref final−Pref initial)/(Ppump initial−Ppump final)
Control unit 80 in method 150 is programmed to measure a final volume of fresh or used dialysis fluid located between flexible sheet 112 and fluid contacting rigid plastic shell 114 using the same two sets of pressure measurements and an equation based on the ideal gas law. At block 162, control unit 80 opens positive pneumatic valve 52a, opens a desired destination pinch valve 34, 36a or 38 and runs air pump 40 so as to create a desired positive pumping pressure and push fresh or used dialysis fluid from pod pump 110.
At block 164, in a first set of pressure measurements, control unit 80 takes pressure measurements of (i) the air side of the disposable pumping pod 110 using the pod pressure sensor 48a and (ii) reference chamber 60 using reference pressure chamber 48b.
At block 166, in a second set of pressure measurements, control unit 80 opens one or more pneumatic reference valve(s) 54a and/or 54b to allow the air side of disposable pumping pod 110 and reference chamber 60 to communicate pneumatically. Here, both pod pressure sensor 48a and reference pressure sensor 48b measure the pressure of the combined pneumatic cavity. The difference between the first set of measurements at block 164 and the second set of measurements at block 166 is that the first pressure readings at block 164 are taken before pneumatically connecting pumping pod 110 and reference chamber 60, while the second pressure readings at block 166 are taken after pneumatically connecting pumping pod 110 and reference chamber 60.
At block 168, with all values on the right side of the following equation (based on the ideal gas law) known or measured, including the known volume of reference chamber 60, control unit 80 calculates the volume of fresh or used dialysis fluid remaining in pod pump 110 after the discharge stroke as follows:
V
fluid final
=V
reference chamber*(Pref final−Pref initial)/(Ppump initial−Ppump final)
At block 170, control unit 80 calculates the volume of fresh or used dialysis fluid pumped from pod pump 110 by calculating the difference between the calculated fluid volume after drawing in fluid (Vfluid initial) and the calculated fluid volume after pumping fluid out (Vfluid final) pumping.
At block 172, control unit adds the volume of fresh or used fluid pumped determined at block 170 with a previously accumulated volume of fresh or used dialysis fluid pumped.
At diamond 174, control unit 80 determines whether the accumulated volume of fresh or used dialysis fluid pumped updated at block 172 meets a required or prescribed volume of fresh or used dialysis fluid to be pumped. If not, then method 150 returns to block 154 and repeats the above sequence. If so, then method 150 ends at oval 176.
The same pumping regime described in connection with method 150 is used to pump fluid from any fluid source described herein to any destination described herein. In steps 158 and 160, both pressure sensors 48a and 48b should read and output the same pressure values to control unit 80. The readings from pressure sensors 48a and 48b could be averaged to provide an average pressure value that is used for operation, or the pressure reading from one of the sensors, e.g., sensor 48a may be used for operation, while the reading from the other pressure sensor 48b may be used as a redundant reading to see if primary pressure sensor 48a has drifted.
Referring now to
As before, a disposable set, here set 100b, including a pod pump 110 is inserted for operation inside of APD cycler 20b, for example, in between an actuation surface and a door 26 of the APD cycler. Door 26, for example, hinges open via one or more hinge located along a bottom of cycler housing 22b, adjacent to actuation surface 24. Disposable set 100b also includes multiple peritoneal dialysis fluid containers or bags 102a to 102c, wherein one of the containers, e.g., container 102a, is placed on top of cycler 20b, which includes a dialysis fluid heater to heat dialysis fluid located originally in container 102a as well as dialysis fluid pumped to container 102a from second and third containers 102b and 102c for subsequent patient fills. As before, the plate or batch heater may be replaced by an inline heater dialysis fluid heater, which heats fresh dialysis fluid as it flows through patient line 108 to the patient.
Air pump 40, pneumatic valve manifold 50 and known volume reference chamber 60, including all structure, functionality and alternatives discussed above for cycler 20a are located within housing 22b of cycler 20b. All electronic components of cycler 20b are under control of and/or output to control unit 80 described above. Control unit 80 controls air pump 40 and pneumatic valve manifold 50 using reference chamber 60 to pump fresh and used dialysis fluid to and from pumping pod 110 according to method 150 of
One difference with cycler 20b is that user interface 88 is connected to housing 22b via a bracket 88a that connects hingedly to housing 22b via a hinge 88b. When not needed, user interface 88 folds conveniently out of the way and into the front of housing 22b as illustrated in
In the illustrated embodiment of
One difference with disposable set 100b is that the disposable portion of drain line 104d is shortened, reducing waste and cost. Disposable portion of drain line 104d includes a connector 130 that attaches to a reusable drip chamber 180 illustrated and described in more detail below. A reusable portion of drain line 104r extends from the bottom of reusable drip chamber 180 to a drain container or bag or to a house drain, such as a toilet, bath or sink. Reusable portion of drain line 104r is significantly longer than disposable portion 104d, reducing cost.
Referring now to
Referring now to
Sensor(s) 70 is/are provided to look to ensure that an air column exists within sensing portion 182 of reusable drip chamber 180. The air column helps to ensure the sterility of used dialysis fluid flowing through disposable portion of drain line 104d. That is, over time impurities may form in reusable portion of drain line 104r. The air column formed in drip chamber 180, however, ensures that there is no fluid path for any pathogens to flow from reusable portion of drain line 104r to disposable portion of drain line 104d. The only path is for the pathogens to migrate up the inner wall of sensing portion 182, which is a tortuous path. Additionally, the small disposable portion of drain line 104d still provides a relatively long path for any pathogen(s) that is/are able to migrate into disposable portion 104d, against the flow of used dialysis fluid and during a single treatment.
In the illustrated embodiment, male threads 138 are provided on the opposite side of flange 136 from stop 134. Male threads 138 mate sealingly with female threads 190 provided at the top of reusable drip chamber 180. A shroud 140 extends from male threads 138 past a concentric inner port 142 from which used dialysis fluid forms droplets that fall from connector 130 into reusable drip chamber 180. The additional extension of shroud 140 past inner port 142 tends to prevent a user from touching an end of inner port 142 and potentially contaminating same.
When connector 130 is inserted, e.g., threaded, into the top of reusable drip chamber 180, shroud 140 extends past a port 192 of the drip chamber. Port is provided for connection to an air or pneumatic line leading to an air pump, which may be system air pump 40 or a separate small, dedicated air pump under control of control unit 80. For example, the air or pneumatic line may extend from port 192, through an aperture formed in housing 22a to 22c of cyclers 20a to 20c, to the air pump. The air pump pumps air into reusable drip chamber 180 to help ensure that the air column is present. Air may be pumped into reusable drip chamber 180 continuously during drain or upon sensor(s) 70, e.g., lower sensor 70b in
In an alternative embodiment, the air or pneumatic line extends from port 192 to a hydrophobic vent located at its distal end, which may be routed so as to reside within housing 22a to 22c. The hydrophobic vent filters air entering the line due to negative pressure created via a venturi effect of the effluent fluid flowing through reusable drip chamber 180. The air pulled in through port 192 extends to sensing portion 182 to help maintain the air column.
It should be appreciated however that reusable drip chamber 180 and drain line portions 104d and 104r do not have to be provided with or operate with a disposable set, with a cycler that operates a disposable set, or with a pneumatically operated cycler. Reusable drip chamber 180 and drain line portions 104d and 104r may operate alternatively with any type of pumping, such as peristaltic pumping, piston pumping, centrifugal pumping, etc. The pumping (valving and heating) may further alternatively be durable, not disposable, in which fresh and used PD fluid flows through the durable PD fluid pump over many treatments. The durable cycler may be disinfected in between treatments. Here, disposable portion of drain line 104d may be plugged directly into the cycler during treatment to communicate fluidly with one or more internal, reusable drain line.
For disinfection, the patient or user may remove disposable portion of drain line 104d from a drain connector of the cycler. If so, the drain connector includes a cover or cap that seals the drain connector closed during disinfection. The patient or user may remove the disposable portion of drain line 104d from reusable drip chamber 180 so that portion 104d can be discarded. The patient or user caps reusable drip chamber 180 and the distal end of reusable portion 104r as discussed above. Alternatively, the patient or user leaves the disposable portion of drain line 104d in place during disinfection, connected to the drain connector of the cycler and the top of reusable drip chamber 180. Here, the cycler fluidly isolates the drain connector, or at least a portion thereof, during disinfection, so that disinfection fluid does not flow into the left-in-place disposable portion of drain line 104d. In any of the above embodiments, disinfection may then proceed assuming any other needed disinfection connections (e.g., patient line, dialysis fluid supply lines) have been made.
The primary differences with alternative cycler 20c are that user interface 88 is built into or integrated with housing 22c instead of being hinged to the housing. User interface may likewise be built into housings 22a and 22b of cyclers 20a and 20b. A primary difference with alternative cycler 20c is that the lid of housing 22c may be split into two halves 22h, e.g., equally sized halves. Each half 22h may then hinge outwardly open for receiving and supporting a portion of container or bag 102a. When halves 22h are open, a heating tray having heater 30 and temperature sensors 32 under control of control unit 80 is exposed for controllably heating fresh dialysis fluid located within container or bag 102a. Rotatable halves 22h enable the overall size of housing 22c to be smaller and to not be constrained in two dimensions to being at least the size of container or bag 102a.
Referring now to
Linear actuator 92 in one embodiment includes a rotary nut motor having female threads (not illustrated) that rotate threadingly around male threads of a threaded shaft 94. The female threads rotate but are constrained so as not to translate along the axis of threaded shaft 94, which causes the threaded shaft to translate back and forth along the central axis extending through shaft 94 and linear actuator 92. Linear actuator 92 is bidirectional so that when control unit 80 causes the female threads to turn in a first direction, threaded shaft 94 is pulled into the linear actuator, opening a line 104, 106a to 106c or 108. When control unit 80 instead causes the female threads to turn in a second direction, threaded shaft 94 is pushed out of the linear actuator, closing a line 104, 106a to 106c or 108.
A mounting flange 96 is located about threaded shaft 94. Mounting flange 96 includes or defines clearance holes 96a to 96d that accept screws that thread into respective threaded holes or bores 98a to 98d provided in a plunger 98. Plunger 98 is thus fixed to mounting flange 96. Plunger 98 and mounting flange 96 constrain a compression spring 194. When plunger 98 is pulled away from and is not contacting a line 104, 106a to 106c or 108, compression spring 194 pushes plunger 98 against a collar 196, which is fixed to threaded shaft 94, e.g., via a set screw, which in turn pulls mounting flange 96 to abut against or away from a collar 196. When plunger 98 is pushed towards and makes contact with a line 104, 106a to 106c or 108, compression spring 194 compresses and allows plunger 98 and mounting flange 96 to translate towards linear actuator 92 slightly relative to fixed collar 196 until the compression spring 194 becomes fully compressed. The slight amount of play provides greater tolerance to the pinch valve 34, 36a to 36c and 38.
The distal end of plunger 98 extends through an aperture 90e provided in housing 90 to reach line 104, 106a to 106c or 108. Aperture 90e also centers and constrains the movement of the distal end of plunger 98. In one embodiment, the combination of the movement of threaded shaft 94 and the force of compression spring 194 (sized selectively in at least one of length, coil diameter and spring material) provides enough extension distance and spring force to fully occlude lines 104, 106a to 106c and 108 even under the highest possible positive dialysis fluid pressure, e.g., 8 psig.
In the illustrated embodiment, pinch valve 34, 36a to 36c or 38 is provided with a sensor 198, which may be attached to the back of linear actuator 92 or to a portion of housing 22a to 22c of cyclers 20a to 20c, respectively. In either case, sensor 198 is positioned to sense whether a proximal end 94p of threaded shaft 94 is present or not, that is, whether the proximal end 94p has been pulled back to the point that it extends through the back end of linear actuator 92 (indicating an open or fluid flow valve position). Sensor 198 may be an optical, capacitive, ultrasonic or other type of sensor outputting to control unit 80, which is capable of detecting the presence or not of the proximal end 94p of threaded shaft 94. In an embodiment, control unit 80 is programmed to look to see from the output of sensor 198 that the proximal end 94p is not present at a time when pinch valve 34, 36a to 36c or 38 is supposed to be closed to occlude flow through line 104, 106a to 106c and 108. If the output from sensor 198 indicates that proximal end 94p is not present at a time when the pinch valve is supposed to be closed, then treatment proceeds as planned. If the output from sensor 198 indicates that proximal end 94p is present at a time when the pinch valve is supposed to be closed, then treatment is stopped and an audio, visual or audiovisual alarm is provided at user interface 88 in one embodiment.
Each of the components of pinch valve 34, 36a to 36c or 38 described above, including housing 90, linear actuator 92, threaded shaft 94, mounting flange 96, plunger 98, spring 194, collar 196, and sensor 198 may be formed from metal, such as stainless steel, steel and/or aluminum, and/or molded from plastic, such as polyvinylchloride (“PVC”) or a non-PVC material, such as polyethylene (“PE”), polyurethane (“PU”) or polycarbonate (“PC”).
Referring now to
An issue with air pumps in general is noise, which is heightened in the present disclosure because a primary mode of use for cyclers 20a to 20c is at night while the patient sleeps. Air pump 40 of the present disclosure mitigates audible noise via a box-in-a-box configuration.
In the illustrated embodiment, pump body 40a is housed inside of a first noise-reducing enclosure, which is formed from a plurality of acoustic foam sheets 64. Acoustic foam sheets 64 may for example be six to fifteen millimeters thick or even thicker, e.g., up to twenty-five millimeters thick and may be made of high density polyethylene (“HDPE”). Acoustic foam sheets 64 may be secured together to form the first enclosure, e.g., adhered and/or fastened together, with the top acoustic foam sheet 64 left unattached so that pump body 40a may be placed inside of the first enclosure. Acoustic foam sheets 64 are alternatively secured, e.g., adhered and/or fastened, to the insides of walls 46a and 46b of a second or outer noise-reducing enclosure. Walls 46a and 46b may be made of any of the metal or plastic materials discussed herein and may be four to twelve millimeters thick. Walls 46a include or form the sides and bottom of the outer enclosure, while wall 46b includes the top of the outer enclosure, which is removable so that pump body 40a may be placed inside of the first and second enclosures. The first and second enclosures may include mating one or more aperture(s) that allow pneumatic tubing or lines and electrical wiring to run to pump body 40a.
The outer enclosure is also made of a noise reducing or attenuating material. The combination of the inner and outer enclosures allows the audible noise output from air pump 40 to be reduced to about thirty-one to thirty-two dB. It is contemplated to further reduce the noise output by placing spacers between the inner enclosure (formed from acoustic form sheets 64) and the outer enclosure (formed from walls 46a and 46b) so as to create an air gap between the enclosures. The air gap acts as a third noise reducing layer.
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. For example, pneumatic valves may be used instead of electrically actuated pinch valves. In another example, separate positive and negative air pumps may be used to supply positive and negative air pressure instead of single air pump 40. In a further example, heater 30 could be located remote from cycler 20a. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202141008530 | Mar 2021 | IN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/017249 | 2/22/2022 | WO |
