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EP-4233987-B1 - BLOOD TREATMENT SYSTEMS

EP4233987B1EP 4233987 B1EP4233987 B1EP 4233987B1EP-4233987-B1

Inventors

  • WILT, MICHAEL J.
  • VAN DER MERWE, DIRK A.
  • DALE, JAMES D.
  • TRACEY, BRIAN D.
  • GRANT, KEVIN L.
  • DEMERS, JASON A.
  • FLYNN, CATHARINE N.

Dates

Publication Date
20260506
Application Date
20140314

Claims (14)

  1. A system for monitoring fluid flow in an extracorporeal blood circuit comprising: a pumping chamber (111) of a blood pump (101) separated from a control chamber (112) of the blood pump by a flexible diaphragm (109), the control chamber configured to transmit positive or negative pressure to operate the diaphragm; a pressure sensor (114) configured to measure pressure in the control chamber (112) of the blood pump (101); a controller (119) configured to receive information from the pressure sensor (114), and configured to control the delivery of pressure to the control chamber (112) of the blood pump (101); wherein the controller (119) is configured to cause an application of a time-varying pressure waveform on the blood pump diaphragm (109) during a fill-stroke of the blood pump (101), and to monitor a pressure variation in the control chamber (112) measured by the pressure sensor (114), and wherein the controller (119) is configured to determine a blood flow metric based on a variation of a peak-to-peak magnitude of the measured pressure during the course of a fill-stroke of the blood pump and to alert a user based on the blood flow metric.
  2. The system of claim 1, wherein a variation of the peak-to-peak magnitude of the measured pressure variation that deviates from a pre-determined value causes the controller (119) to provide a notification to the user.
  3. The system of claim 1 or 2, wherein the controller (119) is configured to compare a pressure variation in the control chamber measured by the pressure sensor with a target signal variation or target pressure variation induced by the controller, and wherein a deviation between the measured pressure variation and the target signal variation or target pressure variation that is greater than a pre-determined value causes the controller to provide a notification to the user.
  4. The system of any one of the preceding claims, wherein the time-varying pressure waveform comprises a sinusoidal pressure waveform.
  5. The system of any one of the preceding claims, wherein the controller (119) controls the application of the time-varying pressure waveform by controlling a variable restriction valve (117, 118) interposed between the control chamber (112) and a source of positive or negative pressure (121, 122).
  6. The system of claim 5, wherein the source of positive or negative pressure (121, 122) comprises a source of positive pneumatic pressure (121) and a source of negative pneumatic pressure (122).
  7. The system of any one of the preceding claims, wherein the controller (119) is configured to display a value of the blood flow metric on a graphical user interface.
  8. The system of claim 7, wherein the controller (119) is configured to transmit one of a plurality of representative values to the graphical user interface, each said representative value representing one of a pre-determined range of values of the blood flow metric.
  9. The system of any one of the preceding claims, wherein the controller (119) is configured to pause or stop a dialysate pump based on the blood flow metric.
  10. The system of any one of claims 1 to 8, wherein the controller (119) is configured to pause or stop a dialysate pump when the blood flow metric drops below a pre-determined value.
  11. The system of claim 9 or 10, wherein the controller (119) is configured to restart the dialysate pump after the blood flow metric is above a predetermined blood flow metric for a predetermined number of fill strokes.
  12. The system of any one of the preceding claims, wherein the controller (119) is configured to allow a sub-standard blood flow metric to exist for two or more pump strokes, during which the user is alerted to the condition.
  13. The system of any one of the preceding claims, wherein the controller (119) is configured to alert the user before the blood flow metric reaches a threshold value to initiate suspension of a dialysate pump.
  14. The system of any one of the preceding claims, wherein the controller (119) is configured to alert the user so the user may attempt to improve blood flow in a blood line.

Description

FIELD OF INVENTION The present invention generally relates to hemodialysis and similar dialysis systems, e.g., systems able to treat blood or other bodily fluids extracorporeally. In certain aspects, the systems include a variety of systems and methods that would make hemodialysis more efficient, easier, and/or more affordable. BACKGROUND Many factors make hemodialysis inefficient, difficult, and expensive. These factors include the complexity of hemodialysis, the safety concerns related to hemodialysis, and the very large amount of dialysate needed for hemodialysis. Moreover, hemodialysis is typically performed in a dialysis center requiring skilled technicians. Therefore any increase in the ease and efficiency of the dialysis process could have an impact on treatment cost or patient outcome. Fig. 1 is a schematic representation of a hemodialysis system. The system 5 includes two flow paths, a blood flow path 10 and a dialysate flow path 20. Blood is drawn from a patient. A blood flow pump 13 causes the blood to flow around blood flow path 10, drawing the blood from the patient, causing the blood to pass through the dialyzer 14, and returning the blood to the patient. Optionally, the blood may pass through other components, such as a filter and/or an air trap 19, before returning to the patient. In addition, in some cases, anticoagulant may be supplied from an anticoagulant supply 11 via an anticoagulant valve 12. A dialysate pump 15 draws dialysate from a dialysate supply 16 and causes the dialysate to pass through the dialyzer 14, after which the dialysate can pass through a waste valve 18 and/or return to the dialysate feed via dialysate pump 15. A dialysate valve 17 controls the flow of dialysate from the dialysate supply 16. The dialyzer is a type of filter having a semi-permeable membrane, and is constructed such that the blood from the blood flow circuit flows through tiny tubes and the dialysate solution circulates around the outside of the tubes. Therapy is achieved by the passing of waste molecules (e.g., urea, creatinine, etc.) and water from the blood through the walls of the tubes and into the dialysate solution. At the end of treatment, the dialysate solution is discarded. Systems for performing hemodialysis are, for example, disclosed in WO 2010/027437 A2, US 2002/088497 A1, and US 2009/099498 A1. SUMMARY OF THE INVENTION The claimed invention is defined by the subject matter of independent claim 1, wherein preferred embodiments are specified in the dependent claims. The present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of one or more systems and/or articles. Although the various systems and methods described herein are described in relation to hemodialysis, it should be understood that the various systems and method described herein are applicable to other dialysis systems and/or in any extracorporeal system able to treat blood or other bodily fluids, such as hemofiltration, hemodiafiltration, etc. In certain embodiments, the disclosure relates to a flexible diaphragm for use in a reciprocating diaphragm pump. The diaphragm pump may comprise a first rigid body having a curved pumping chamber wall, and a second rigid body having an opposing curved control chamber wall. The diaphragm may be configured to be interposed between the pumping chamber wall and the control chamber wall. In certain such embodiments, the diaphragm comprises: a peripheral bead arranged to locate the diaphragm between the first rigid body and the second rigid body; a diaphragm body having a curved, semi-spheroid or domed shape, the diaphragm body configured to generally conform to a curved inner surface of the pumping chamber wall or a curved inner surface of the control chamber wall, and the diaphragm body may have a pumping side arranged to face the inner surface of the pumping chamber wall and an opposing control side arranged to face the inner surface of the control chamber wall. The diaphragm may further comprise: a transition region between the bead and the diaphragm body, the transition region arranged to be pinched or clamped between a clamping region of the first rigid body and an opposing clamping region of the second rigid body. Such diaphragm may be pre-formed or molded with its control side having a convex shape, such that any elastic tension in the diaphragm is reduced when the control side of the diaphragm body assumes a convex shape when positioned in the diaphragm pump. In certain embodiments, the disclosure relates to a reciprocating diaphragm pump comprising a first rigid body having a pumping chamber wall, a second rigid body having an opposing control chamber wall, and a diaphragm configured to be interposed between the pumping chamber wall and the control chamber wall to define a pumping chamber and a control chamber. In certain such embodiments, the diaphragm comprises: a peripheral bead arranged t