US-20260124349-A1 - INLINE HEATER OVERHEATING SYSTEM AND METHOD

US20260124349A1US 20260124349 A1US20260124349 A1US 20260124349A1US-20260124349-A1

Abstract

An inline heating system for a dialysis machine is disclosed. In an example, the inline heating system includes an inline heater comprising a heater element. The inline heating system also includes a control unit configured to compare a rate of change in heater element resistance to a set maximum rate of change in heater element resistance as part of a no flow or low flow condition detection algorithm implemented by the control unit. Power applied to the inline heater is stopped when a no flow or low flow condition is detected using the no flow or low flow condition detection algorithm to prevent overheating of the inline heater.

Inventors

Oskar Erik Frode Styrbjorn Fallman
Michael PETTERSSON
Jimmie Marcus Axel Hansson

Assignees

BAXTER INTERNATIONAL INC.
BAXTER HEALTHCARE SA

Dates

Publication Date: 20260507
Application Date: 20260105

Claims (20)

1 . An inline heating system comprising: an inline heater including a heater element; and a control unit configured to compare a rate of change in heater element resistance to a set maximum rate of change in heater element resistance as part of a no flow or low flow condition detection algorithm implemented by the control unit, wherein power applied to the inline heater is stopped when a no flow or low flow condition is detected using the no flow or low flow condition detection algorithm.
2 . The inline heating system of claim 1 , wherein the control unit is further configured to compare at least one determined heater element resistance to at least one calibrated heater element resistance as part of the no flow or low flow condition detection algorithm implemented by the control unit.
3 . The inline heating system of claim 2 , wherein the at least one calibrated heater element resistance is determined remote from the inline heating system and then stored in the control unit.
4 . The inline heating system of claim 2 , wherein the at least one calibrated heater element resistance is specific to at least one of (i) a fluid flowrate through the inline heater, or (ii) input power to the inline heater.
5 . The inline heating system of claim 1 , which is provided as part of a peritoneal dialysis machine, hemodialysis machine, hemofiltration machine, hemodiafiltration machine, continuous renal replacement therapy machine, water purification unit, dialysis fluid preparation unit, or a blood warmer.
6 . The inline heating system of claim 1 , wherein the control unit is configured to cause one of a voltage or a current from a voltage source to be applied to power the inline heater.
7 . The inline heating system of claim 6 , further comprising at least one of a current or voltage meter outputting to the control unit and arranged to measure at least one of the current or the voltage at the heater element due to the applied voltage and/or current, wherein the control unit is further configured to determine the rate of change in heater element resistance using the measured at least one of the current or the voltage.
8 . The inline heating system of claim 7 , wherein the control unit includes the at least one of the current or voltage meter.
9 . The inline heating system of claim 6 , further comprising: measurement circuitry configured to measure at least one of the current or the voltage at the heater element; and a differential circuit configured to determine the rate of change in heater element resistance using the at least one of the current or the voltage at the heater element.
10 . The inline heating system of claim 9 , wherein the differential circuit includes at least one of (i) a passive capacitive differential circuit that includes a capacitor and resistor, (ii) a passive inductive differential circuit that includes an inductor and a resistor, or (iii) an active differential circuit, which includes a capacitor, a resistor, and an operation amplifier.
11 . The inline heating system of claim 1 , wherein the control unit is further configured to generate an alert indicative of the no flow or low flow condition.
12 . The inline heating system of claim 1 , wherein the control unit is configured to begin operating the no flow or low flow condition detection algorithm responsive to determining or receiving an indication of dialysis fluid flowing through a fluid heating pathway that includes the inline heater.
13 . The inline heating system of claim 1 , wherein the control unit is configured to begin operating the no flow or low flow condition detection algorithm responsive to causing a pump to pump dialysis fluid.
14 . The inline heating system of claim 1 , wherein the control unit is configured to begin operating the no flow or low flow condition detection algorithm responsive to causing power to be applied to the inline heater.
15 . A method of detecting a no flow or low flow condition in a peritoneal dialysis machine, the method comprising: causing, using a control unit, a pump to pump dialysis fluid through at least a fluid heating pathway including an inline heater, the inline heater including a heater element; causing, using the control unit, one of a voltage or a current from a voltage source to be applied to power the inline heater; measuring, using measurement circuitry or the control unit and at least one of a current or voltage meter, at least one of the current or the voltage at the heater element; determining, using a differential circuit or the control unit, a rate of change in heater element resistance; comparing, using a comparator or the control unit, a set maximum rate of change in heater element resistance; and determining, using the comparator or the control unit, the no flow or low flow condition when the rate of change in heater element resistance exceeds the set maximum rate of change in heater element resistance.
16 . The method of claim 15 , wherein the control unit or the comparator is further configured to compare at least one determined heater element resistance to at least one calibrated heater element resistance.
17 . The method of claim 16 , wherein the at least one calibrated heater element resistance is determined remote from the peritoneal dialysis machine and then stored in the control unit or the comparator.
18 . The method of claim 16 , wherein the at least one calibrated heater element resistance is specific to at least one of (i) a fluid flowrate through the inline heater, or (ii) input power to the inline heater.
19 . The method of claim 15 , further comprising generating, using the control unit, an alert indicative of the no flow or low flow condition.
20 . The method of claim 15 , wherein the comparator or the control unit is configured to use a no flow or low flow condition detection algorithm to determine the no flow or low flow condition.

Description

PRIORITY CLAIM The present application is a continuation application of U.S. patent application Ser. No. 17/903,366, filed on Sep. 6, 2022, which claims priority to and the benefit of U.S. Provisional Patent Application No. 63/241,738 , filed on Sep. 8, 2021, the entire contents of which are hereby incorporated herein by reference and relied upon. BACKGROUND The present disclosure relates generally to medical fluid treatments and in particular to the heating of treatment fluid during 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 or PD fluid, into a patient's peritoneal chamber via a catheter. The PD fluid comes into 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 PD fluid due to diffusion and osmosis, i.e., an osmotic gradient occurs across the membrane. An osmotic agent in the PD fluid provides the osmotic gradient. Used PD fluid is drained from the patient, removing waste, toxins and excess water from the patient. This cycle is repeated, e.g., multiple times. There are various types of peritoneal dialysis therapies, including continuous ambulatory peritoneal dialysis (“CAPD”), automated peritoneal dialysis (“APD”), tidal flow dialysis and continuous flow peritoneal dialysis (“CFPD”). CAPD is a manual dialysis treatment. Here, the patient manually connects an implanted catheter to a drain to allow used PD fluid to drain from the patient's peritoneal cavity. The patient then switches fluid communication so that the patient catheter communicates with a bag of fresh PD fluid to infuse the fresh PD fluid through the catheter and into the patient. The patient disconnects the catheter from the fresh PD fluid bag and allows the PD fluid to dwell within the patient's peritoneal cavity, wherein the transfer of waste, toxins and excess water takes place. After a dwell period, the patient repeats the manual dialysis procedure, for example, f