Patent Application
20250205402
The present disclosure relates generally to medical 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. Automated PD machines, however, perform the cycles automatically, typically while the patient sleeps. The PD machines free patients from having to manually perform the treatment cycles and from having to transport supplies during the day. The PD machines connect fluidly to an implanted catheter, to a source or bag of fresh dialysis fluid and to a fluid drain. The PD machines pump fresh dialysis fluid from a dialysis fluid source, through the catheter and into the patient's peritoneal chamber. The PD 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.
The PD machines pump used or spent dialysate from the patient's peritoneal cavity, though the catheter, to drain. As with the manual process, several drain, fill and dwell cycles occur during dialysis. A “last fill” may occur at the end of an APD treatment. The last fill fluid may remain in the peritoneal chamber of the patient until the start of the next treatment, or may be manually emptied at some point during the day.
The present disclosure sets forth an automated peritoneal dialysis (“PD”) system and associated methodology, which determine if an occlusion has occurred within a portion of the PD fluid pathway, such as a patient line during a patient drain of the PD treatment. The present disclosure also sets forth an automated peritoneal dialysis (“PD”) system and associated methodology, which determine the intraperitoneal pressure of a patient during therapy. The system includes a PD machine or cycler. The PD machine is capable of delivering fresh, heated PD fluid to the patient at, for example, 14 kPa (2.0 psig) or higher. The PD machine is capable of removing used PD fluid or effluent from the patient at, for example, −9 kPa (−1.3 psig) or lower Fresh PD fluid is delivered in one embodiment via a dual lumen patient line to the patient and is first heated to body fluid temperature, e.g., 37° C. The heated PD fluid is then pumped through a fresh PD fluid lumen of the dual lumen patient line to a disposable filter set. The disposable filter set communicates fluidly with the fresh and used PD fluid lumens of the dual lumen patient line, which are heat disinfected and reusable in one embodiment. The disposable filter set includes a sterilizing grade filter membrane that further filters fresh PD fluid. The disposable filter set is provided in one embodiment with one or more hydrophobic filters or vents upstream from the sterilizing grade filter membrane.
A used PD fluid lumen of the dual lumen patient line carries used PD fluid or effluent from the disposable filter set back to the PD machine. The used PD fluid or effluent is pumped along one or more internal line of the PD machine to a flexible, e.g., disposable, drain line, which carries the used PD fluid or effluent to a drain container or house drain. A PD fluid pump of the PD machine is located along one of the internal lines and pumps used PD fluid or effluent under negative pressure to the PD fluid pump and under positive pressure from the PD fluid pump. One or more pressure sensor is located along the internal line (or a line in fluid communication with the internal line) so as to sense the negative pressure of used PD fluid or effluent drawn to the PD fluid pump. Likewise, one or more pressure sensor may be applied to an internal line (or a line in fluid communication with the internal line) extending from the PD fluid pump to a fresh PD fluid lumen of the dual lumen patient line for sensing positive pressure during a patient fill.
In light of the disclosure set forth herein, and without limiting the disclosure in any way, in a first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) system includes a PD fluid pump configured to pump PD fluid along a line under an upstream pressure and to create an upstream pressure profile having a maximum upstream pressure and a minimum upstream pressure; a pressure sensor positioned and arranged to sense the upstream pressure profile and to produce an output indicative of the upstream pressure profile including a maximum upstream pressure output and a minimum upstream pressure output; and a control unit configured to analyze the output indicative of the upstream pressure profile and to determine that an occlusion in the line has occurred if both the maximum upstream pressure output and the minimum upstream pressure output change by at or more than a set pressure delta, wherein the set pressure delta is optionally the same pressure delta for the maximum upstream pressure output and the minimum upstream pressure output.
In a second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the set pressure delta is different for the maximum upstream pressure output and the minimum upstream pressure output.
In a third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the set pressure delta is selected to avoid a false occlusion detection in the line and so as to detect a partial occlusion in the line.
In a fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the upstream pressure profile is a sinusoidal profile.
In a fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the line under upstream pressure is a flexible patient line and optionally a used PD fluid lumen of a flexible dual lumen patient line.
In a sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the line under upstream pressure is an internal line of a PD machine of the PD system.
In a seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD fluid pump is located along an internal line in fluid communication with the line under upstream pressure, and wherein the pressure sensor is positioned and arranged along the internal line or a third line in fluid communication with the internal line.
In an eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to determine the change by comparing (i) a most recent maximum upstream pressure output to a next most recent maximum upstream pressure output, and (ii) a most recent minimum upstream pressure output to a next most recent minimum upstream pressure output.
In a ninth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to determine the change by comparing (i) a most recent maximum upstream pressure output to an average maximum upstream pressure output including a next most recent maximum upstream pressure output, and (ii) a most recent minimum upstream pressure output to an average minimum upstream pressure output including a next most recent minimum upstream pressure output.
In a tenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, at least one of the average maximum upstream pressure output or the average minimum upstream pressure output is a rolling average.
In an eleventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured to determine the change by comparing (i) an average maximum upstream pressure output including a most recent maximum upstream pressure output and at least one other maximum upstream pressure output to (a) a maximum upstream pressure output just prior to the at least one other maximum upstream pressure output or (b) a second average maximum upstream pressure output including the just prior maximum upstream pressure output, and (ii) an average minimum upstream pressure output including a most recent minimum upstream pressure output and at least one other minimum upstream pressure output to (a) a minimum upstream pressure output just prior to the at least one other minimum upstream pressure output or (b) a second average minimum upstream pressure output including the just prior minimum upstream pressure output.
In a twelfth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the control unit is configured such that upon determining that an occlusion in the line has occurred, at least one of (i) the PD fluid pump is stopped or (ii) an alarm is sounded and/or displayed.
In a thirteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the upstream pressure is a negative pressure.
In a fourteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) system includes a PD fluid pump configured to pump PD fluid along a line under pressure and to create a pressure profile having a maximum pressure and a minimum pressure; a pressure sensor positioned and arranged to sense the pressure profile and to produce an output indicative of the pressure profile including a maximum pressure output and a minimum pressure output; and a control unit configured to analyze the output indicative of the pressure profile and to determine that an occlusion in the line has occurred if both the maximum pressure output and the minimum pressure output change by at or more than a set pressure delta, wherein the set pressure delta is optionally the same pressure delta for the maximum pressure output and the minimum pressure output.
In a fifteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD fluid pump is configured to pump PD fluid along the line under negative pressure, and wherein the maximum pressure output is a maximum negative pressure output and the minimum pressure output is a minimum negative pressure output.
In a sixteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the line is (i) a patient line, optionally a used PD fluid lumen of a dual lumen patient line or (ii) a PD fluid supply line.
In a seventeenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD fluid pump is configured to pump PD fluid along the line under positive pressure, and wherein the maximum pressure output is a maximum positive pressure output and the minimum pressure output is a minimum positive pressure output.
In an eighteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) method includes during a non-treatment mode, determining a pressure profile created by a PD fluid pump configured to pump PD fluid along a line under pressure, wherein the pressure profile includes a maximum pressure and a minimum pressure; positioning a pressure sensor so as to sense the pressure PD fluid profile, the pressure sensor producing an output indicative of the pressure profile including a maximum non-treatment pressure output and a minimum non-treatment pressure output; and analyzing an output indicative of a pressure profile occurring during treatment and determining that an occlusion in the line has occurred if both (i) a difference between a maximum treatment pressure output and the maximum non-treatment pressure output is at or more than a set pressure delta and (ii) a difference between a minimum treatment pressure output and the minimum non-treatment pressure output is at or more than the set pressure delta, wherein the set pressure delta is optionally the same pressure delta for the maximum pressure difference and the minimum pressure difference.
In a nineteenth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, peritoneal dialysis (“PD”) system includes a housing, a PD fluid pump housed by the housing, a dual lumen patient line extending from the housing, the dual lumen patient line including a fresh PD fluid lumen and a used PD fluid lumen. a filter set in fluid communication with the fresh PD fluid lumen, one or more vents positioned upstream from the filter set, a first pressure sensor in fluid contact with the fresh PD fluid lumen; and a control unit. The control unit is configured to (i) determine a hydrostatic pressure by receiving a first pressure value from the first pressure sensor during a patient drain.
In a twentieth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD system includes a second pressure sensor in fluid contact with the used PD fluid lumen. The controller is further configured to (ii) determine when a flow rate of fluid through the fresh PD lumen and the used PD lumen is zero; (iii) receive a second pressure value from the second pressure sensor when the flow rate is zero; and (iv) estimate an intra peritoneal pressure of a patient using the second pressure value and the hydrostatic pressure.
In a twenty-first aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, estimating the intra peritoneal pressure of the patient includes subtracting hydrostatic pressure from the second pressure value.
In a twenty-second aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the controller is configured to repeat (i) to (iv) during each treatment of the patient.
In a twenty-third aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the controller is configured to: (i) store the intra peritoneal pressure values for each treatment; (ii) determine a variation of intra peritoneal pressure values between each treatment; and (iii) issue an alarm if the variation is above a predetermined threshold.
In a twenty-fourth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the filter set includes a hydrophilic membrane
In a twenty-fifth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the vent includes a hydrophobic membrane
In a twenty-sixth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, a peritoneal dialysis (“PD”) system includes a housing, a PD fluid pump housed by the housing, a dual lumen patient line extending from the housing, the dual lumen patient line including a fresh PD fluid lumen and a used PD fluid lumen, a valve positioned on the fresh PD fluid lumen, wherein the valve is configured to close during a patient drain, a filter set in fluid communication with the fresh PD fluid lumen, the filter set comprising a hydrophilic membrane, and one or more vents positioned upstream from the filter set, the one or more vents comprising a hydrophobic membrane. The pump is configured to draw fluid through the used PD fluid lumen during the patient drain causing air to become trapped between the hydrophobic membrane and the hydrophilic membrane.
In a twenty-seventh aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD system includes a first pressure sensor in fluid contact with the fresh PD fluid lumen; and a control unit configured to: (i) determine a hydrostatic pressure by receiving a first pressure value from the first pressure sensor during the patient drain.
In a twenty-eighth aspect of the present disclosure, which may be combined with any other aspect, or portion thereof, the PD system includes a second pressure sensor in fluid contact with the used PD fluid lumen. The controller is further configured to determine when a flow rate of fluid through the fresh PD lumen and the used PD lumen is zero; receive a second pressure value from the second pressure sensor when the flow rate is zero; and (v) estimate an intra peritoneal pressure of a patient using the second pressure value and the hydrostatic pressure.
In a twenty-ninth 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 set forth herein, it is an advantage of the present disclosure to provide a peritoneal dialysis occlusion detection system and associated methodology having an improved response time.
It is another advantage of the present disclosure to provide a peritoneal dialysis occlusion detection system and associated methodology that is repeatable and reliable.
It is a further advantage of the present disclosure to provide a peritoneal dialysis occlusion detection system and associated methodology that uses existing equipment that is used for other purposes.
Moreover, it is an advantage of the present disclosure to provide a peritoneal dialysis occlusion detection system and associated methodology that uses a larger portion of a pressure sensor output profile and has an increased response time to an occlusion, enabling the patient drain to occur at a higher flowrate and resulting in an improved peritoneal dialysis treatment.
It is yet another advantage of the present disclosure to provide a peritoneal dialysis system that can determine the hydrostatic pressure associated with a pressure sensor inside the PD system to determine intra peritoneal pressure.
Moreover, it is an advantage of the present disclosure to provide a PD system determines a change in intra peritoneal pressure over time to determine problems in the system.
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
System 10 in
System 10 may also include PD fluid containers or bags 38a to 38c (e.g., holding the same or different formulations of PD fluid), which connect to distal ends 24d of reusable PD fluid lines 24a to 24c, respectively. System 10d further includes a fourth PD fluid container or bag 38d that connects to a distal end 24d of reusable PD fluid line 24e. Fourth PD fluid container or bag 38d may hold the same or different type (e.g., icodextrin) of PD fluid than provided in PD fluid containers or bags 38a to 38c. Reusable PD fluid lines 24a to 24c and 24e extend in one embodiment through apertures (not illustrated) defined or provided by housing 22 of cycler 20.
System 10 in the illustrated embodiment includes four disinfection connectors 30a to 30d for connecting to distal ends 24d of reusable PD fluid lines 24a to 24c and 24e, respectively, during disinfection. System 10 also provides a patient line connector 32 that includes an internal lumen, e.g., a U-shaped lumen, which for disinfection directs fresh or used dialysis fluid from one PD fluid lumen of a connected distal end 28d of dual lumen reusable patient line 28 into the other PD fluid lumen. Reusable supply tubing or lines 52a1 to 52a4 communicate with reusable supply lines 24a to 24c and 24e, respectively. Reusable supply tubing or lines 52a1 to 52a3 operate with valves 54a to 54c, respectively, to allow PD fluid from a desired PD fluid container or bag 38a to 38c to be pulled into cycler 20. Three-way valve 94a in the illustrated example allows for control unit 100 to select between (i) 2.27% (or other) glucose dialysis fluid from container or bag 38b or 38c and (ii) icodextrin from container or bag 38d. In the illustrated embodiment, icodextrin from container or bag 38d is connected to the normally closed port of three-way valve 94a.
System 10 is constructed in one embodiment such that drain line 52i during a patient fill is fluidly connected downstream from PD fluid pump 70. In this manner, if drain valve 54i fails or somehow leaks during the patient fill of patient P, fresh PD fluid is pushed down disposable drain line 36 instead of used PD fluid potentially being pulled into pump 70. Disposable drain line 36 is in one embodiment removed for disinfection, wherein drain line connector 34 is capped via a cap 34c to form a closed disinfection loop. PD fluid pump 70 may be an inherently accurate pump, such as a piston pump, or less accurate pump, such as a gear pump that operates in cooperation with a flowmeter (not illustrated) to control fresh and used PD fluid flowrate and volume.
System 10 may further include a leak detection pan 82 located at the bottom of housing 22 of cycler 20 and a corresponding leak detection sensor 84 outputting to control unit 100. In the illustrated example, system 10 is provided with an additional pressure sensor 78c located upstream of PD fluid pump 70, which allows for the measurement of the suction pressure of pump 70 to help control unit 100 more accurately determine pump volume. Additional pressure sensor 78c in the illustrated embodiment is located along vent line 52e, which may be filled with air or a mixture of air and PD fluid, but which should nevertheless be at the same negative pressure as PD fluid located within PD fluid line 52c.
System 10 in the example of
System 10 in the example of
Control unit 100 in an embodiment uses feedback from any one or more of pressure sensors 78a to 78c to enable PD machine 20 to deliver fresh, heated PD fluid to the patient at, for example, 14 kPa (2.0 psig) or higher. The pressure feedback is used to enable PD machine 20 to remove used PD fluid or effluent from the patient at, for example, −9 kPa (−1.3 psig) or higher. The pressure feedback may be used in a proportional, integral, derivative (“PID”) pressure routine for pumping fresh and used PD fluid at a desired positive or negative pressure.
Inline resistive heater 56 under control of control unit 100 is capable of heating fresh PD fluid to body temperature, e.g., 37° C., for delivery to patient P at a desired flowrate. Control unit 100 in an embodiment uses feedback from temperature sensor 58a in a PID temperature routine for pumping fresh PD fluid to patient P at a desired temperature.
Referring to
Likewise, one or more pressure sensor 78a may be located along an internal fresh PD fluid line 52f (or a line in fluid communication with the fresh PD fluid line 52f) extending from PD fluid pump 70 to a fresh PD fluid lumen of dual lumen patient line 28 for sensing positive pressure during a patient fill. The output of one or more pressure sensor P2 (sensor 78b1, 78b2 and/or 78c) is/are used by control unit 100 to detect an occlusion (i) in the used PD fluid lumen of flexible dual lumen patient line 28 or (ii) in any of flexible, reusable PD fluid lines 24a to 24c and 24e. The output of pressure sensor 78a is used by control unit 100 in one embodiment to detect an occlusion in the used PD fluid lumen of flexible dual lumen patient line 28.
PD fluid pump 70 may be any type of fluid pump, such as a piston pump or peristaltic pump.
In system 10, one or more processor 102 and one or more memory 104 of control unit 100 are programmed to analyze or apply one or more algorithm to the upstream (e.g., negative) pressure output of pressure sensor P2 (sensor 78b1, 78b2 and/or 78c) during a patient drain to attempt to detect an occlusion in the used fluid lumen of dual lumen patient line 28. The analysis or algorithm as programmed into control unit 100 in an embodiment analyzes the maximum and minimum peaks in the sinusoidal pressure sensor output profile to determine the presence of an occlusion in the used PD fluid lumen of dual lumen patient line 28.
In one embodiment, the analysis or algorithm of control unit 100 looks to see if both the maximum and minimum peaks in the sinusoidal pressure sensor output profile decrease by more than a threshold pressure change or delta value. If so, control unit 100 determines that an occlusion has occurred, causes PD fluid pump 70 to stop pumping, and may optionally cause an audio, visual or audiovisual alarm to be provided at user interface 108 instructing the patient or caregiver to look for a source of the occlusion. The threshold delta values, e.g., 5 kPa (0.73 psig) or 7 kPa (1.02 psig), may be different for (i) the upper and lower (high/low or maximum/minimum) pressure peaks, and (ii) different types of PD fluid flows, e.g., be different for a patient drain through the used PD fluid lumen of patient line 28, versus a patient fill through the fresh PD fluid lumen of patient line 28, and versus a PD fluid draw through a supply line 24a to 24c, 24e extending to a PD fluid container or bag 38a to 38d. The present analysis or algorithms may be used for any type of PD fluid that flows through a line or tube that may experience an occlusion, especially along flexible PD fluid lines, such as patient line 28 or PD fluid lines 24a to 24c and 24e. The threshold delta values in an embodiment are selected to be large enough to prevent false occlusion detections but on the other hand small enough to detect partial occlusions (used PD fluid lumen only partially kinked) in addition to full occlusions.
Upon the occurrence of the occlusion in
As discussed above, properly selecting the threshold delta values for the high and low trigger point comparisons is important to prevent false occlusion detections but to also be able to detect partial occlusions. Another important determination is the high and low pressure peaks to which the threshold delta values are applied. Depending on the type of pump for PD fluid pump 70, the pump output including suction and delivery pressures may vary over time. If PD fluid pump 70 is a peristaltic pump, for example, the pump tubing actuated by the peristaltic pump rollers may wear and/or soften over time such that the corresponding pumping output changes, typically degrading.
Also, suction and delivery pressures will vary greatly due to patient head height (relative to PD machine 20) regardless of the type of pump for PD fluid pump 70. Patient head height can vary during treatment, e.g., if the patient sits up from a sleeping position, and can vary from treatment to treatment depending on the location of PD machine 20 and the patient, e.g., sleeping on a couch versus a bed. Patient head height offsets the pulsation of the pressure profile, e.g., offsets the midline pressure axis (see, e.g.,
Control unit 100 of system 10 is in one embodiment programmed to compare a most recently sensed set of maximum and minimum (high and low) pressure sensor output peaks to the previously sensed set of maximum and minimum pressure sensor output peaks. Here, if (i) a most recently sensed maximum peak has decreased by at or more than the set pressure delta and (ii) a most recently sensed minimum peak has decreased by at or more than the set pressure delta, then control unit 100 determines that a line occlusion has occurred and takes appropriate action as discussed herein. In
In an alternative embodiment, control unit 100 again uses the most recently sensed set of maximum and minimum pressure sensor output peaks but instead compares those peaks to an average of multiple sets of prior maximum and minimum pressure sensor output peaks, e.g., a ten set rolling average. So in the above example for
In a further alternative embodiment, control unit 100 instead compares an average of a number, e.g., two to five, of the most recent sets of maximum and minimum pressure sensor output peaks to (i) the next most recent set of maximum and minimum pressure sensor output peaks or (ii) an average of multiple next most recent sets of maximum and minimum pressure sensor output peaks. So in the above example for
In any of the above embodiments, if both the high and low pressure sensor output differences are at or greater than the corresponding defined or set threshold pressure sensor output deltas, control unit 100 determines that a line occlusion has occurred and takes appropriate action as discussed herein.
System 10 is expressly not limited to occlusion detection during a patient drain. The plots of
Plots similar to those of
As discussed above, in one embodiment control unit 100 is programmed to compare a most recently sensed set of maximum and minimum pressure sensor output peaks may be compared to maximum and minimum pressure sensor output peaks sensed just prior to the most recent set. At the beginning of treatment however there is no precedent. So assuming for example that the very first pumping procedure of a treatment is for control unit 100 to cause effluent or used PD fluid to be removed from the patient (e.g., from a previous treatment or a midday exchange), control unit 100 may use high and low sets of upstream (e.g., negative) pressure peaks recorded during a priming procedure performed before the initial patient drain. Control unit 100 here may be programmed to use the last or most recent recorded set of high and low upstream (e.g., negative) pressure peaks or an average of multiple sets of high and low upstream (e.g., negative) pressure peaks recorded during the priming procedure for comparison with the first sensed set of high and low upstream (e.g., negative) pressure peaks of the initial patient drain.
Assuming instead that the very first pumping procedure of a treatment is for control unit 100 to cause a patient fill of fresh, heated PD fluid to be delivered to the patient, control unit 100 instead use sets of downstream (e.g., positive) high and low pressure peaks recorded during the priming procedure performed before the initial patient drain. Control unit 100 may again use the last or most recent recorded set of downstream (e.g., positive) high and low pressure peaks or an average of multiple sets of downstream (e.g., positive) high and low pressure peaks recorded during the priming procedure for comparison with the first sensed set of downstream (e.g., positive) high and low pressure peaks of the initial patient fill.
In any of the above embodiments, the control unit 100 is programmed so that air bubbles will not result in a false occlusion detection.
As discussed above, a disposable patient line filter set 40, is connected between reusable patient line 28 and the patient's transfer set.
In the illustrated embodiment, the housing of sterilizing grade filter membrane 46 may be provided with one or more hydrophobic filters or vents, e.g., vents 46a and 46b. In an embodiment, the PD fluid filtering media of sterilizing grade filter membrane 46 is hydrophilic in nature and therefore prevents air from traveling through the filter media once wetted. Sterilizing grade filter membrane 46 accordingly provides a last chance air removal mechanism just prior to the fresh PD fluid reaching the patient. Air collects in the housing of sterilizing grade filter membrane 46 upstream of the filter media, which is vented via hydrophobic filters or vents 46a and 46b located upstream of the filter medial. Hydrophobic filters or vents 46a and 46b filter and remove contaminants from any air that might enter the housing of sterilizing grade filter membrane 46 through the vents.
The configuration of disposable patient line filter set 40 allows the patient's intraperitoneal patient pressure (“IPP”), or very close to it, to be measured. Viewing
During drain, patient fill valve 54f is closed so that patient line 52f is closed causing the PD fluid in fresh disposable line 44a, fresh PD fluid lumen 42a, fresh PD fluid lumen 28a and the reusable circuitry inside the cycler 20 (which may still be at least partially fresh PD fluid from the previous patient fill) is static, not moving. Pressure measured by pressure sensor 78a as positioned in
When the PD fluid in used PD fluid lumen 28b and the PD fluid in fresh fluid lumen 28a are both static and not moving (i.e. flowrate is zero), the pressure measured at pressure sensor 78b as positioned in
Such information may be stored in one or more memory 104 and/or sent from cycler 20 via a wired or wireless connection to a network, e.g., the internet, for storage and analysis in a doctor's or clinician's database.
In one embodiment control unit 100 is programmed to compare a most recently calculated IPP value to IPP values stored in the memory 104 from other treatment sessions. Control unit 100 here may be programmed to issue an alarm if the difference between the recently calculated IPP value and the stored IPP value exceeds a predetermined threshold. The control unit 100 may also be configured to analyze trends in the IPP values over time.
At 120 seconds, the system 10 is configured so that the patient P and the disposable filter set 40 are 140 cm above the PD cycler 20. As illustrated in
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, system 10 does not have to use redundant or durable components, does not have to employ disinfection, such as heat disinfection, does not have to employ a dual lumen patient line, and may instead employ a disposable set having a disposable pumping portion that contacts the corresponding medical fluid. Such disposable cassette may employ dual lumen reusable patient line 28, or a single lumen patient line, and may or may not employ disposable filter set 40. Where a single lumen patient line is provided instead, a single one or more pressure sensor may be located along an internal line of PD fluid machine in fluid communication with the single lumen patient line. While disposable filter set 40 would not be needed as a last chance filter for a system not using heat disinfection, disposable filter set 40 may still be provided if the fresh PD fluid is made online at the time of use as a last chance filter for the online PD fluid. PD fluid pumping with the disposable set may be performed alternatively via pneumatic pump actuation of a sheet of a disposable cassette of the disposable set, via electromechanical pump actuation of a sheet of a disposable cassette of the disposable set, or via peristaltic pump actuation of a pumping tube segment provided with the disposable set.
