System, method, and apparatus for utilizing a pumping cassette

• US 9,488,167 B2
• Filed: 05/29/2014
• Issued: 11/08/2016
• Est. Priority Date: 07/20/1999
• Status: Expired due to Fees

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Gray, Larry B., Bryant, Robert J. Jr., Spencer, Geoffrey P.
• Primary Examiner(s): Schneider, Craig
• Assistant Examiner(s): Rost, Andrew J
• Application Number:
  US14/290,482
• Publication Number:
  US 20140260551A1
• Time in Patent Office: 894 Days
• Field of Search: 251/61.1, 251/128, 417/477.2, 417/477.1, 417/395, 417/394, 417/392, 417/476, 417/474, 277/646, 604/153
• US Class Current: 1/1
• CPC Class Codes: A61M 1/1649 with pulsatile dialysis fluid flow
• CPC Class Codes: A61M 1/267 used for pumping
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362264 the filter being a blood filter
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2209/02 Equipment for testing the apparatus
• CPC Class Codes: A61M 39/228 with a tubular diaphragm constrictable by radial fluid force
• CPC Class Codes: A61M 5/14 Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
• CPC Class Codes: A61M 5/14224 Diaphragm type
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: F04B 43/067 the fluid being actuated directly by a piston
• CPC Class Codes: F04B 45/00 Pumps or pumping installations having flexible working members and specially adapted for elastic fluids
• CPC Class Codes: F04B 45/02 having bellows
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/12 : by varying the length of stroke of the working members
• CPC Class Codes: F04B 53/10 : Valves; Arrangement of valves
• CPC Class Codes: F04B 53/16 : Casings; Cylinders; Cylinder liners or heads; Fluid connections
• CPC Class Codes: G01M 3/26 : by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
• CPC Class Codes: G01M 3/32 : for containers, e.g. radiators
• CPC Class Codes: G05D 16/20 : characterised by the use of electric means

Abstract

The present invention involves, in some embodiments, systems and methods for performing an integrity test on a medical grade cassette that is configured to be used on a medical fluid handling system, wherein the cassette may be disposable and may comprise a membrane therein. The test may be configured to determine an error condition, such as detection of membrane leakage above a threshold value, and may in certain cases be implemented by a medical computer system. In certain cases the integrity test is a dry integrity test and in certain cases, the test is configured to determine a leakage rate of fluid through the membrane.

Claims

1. A method for performing a dry integrity test on a medical-grade cassette, the medical-grade cassette being a single-use disposable cassette that can removably mate with a reusable portion of a dialysis machine, the method comprising:

adjusting a pressure of a pressure tank in the reusable portion;

closing a valve in the reusable portion of the dialysis machine connecting the pressure tank to a membrane of a medical-grade disposable cassette;

measuring a first pressure of the pressure tank within the reusable portion;

opening the valve in the reusable portion;

measuring a second pressure of the pressure tank;

determining a difference between the first and second pressures; and

determining whether the membrane of the medical-grade disposable cassette is leaking above a threshold using the difference.

2. The method according to claim 1, wherein the method is implemented by one or more processors within a medical apparatus.

3. The method according to claim 1, wherein the cassette is loaded into a dialysis machine, wherein the dialysis machine performs the method.

4. The method according to claim 1, wherein the act of determining whether the membrane is leaking above the threshold using the difference comprises the act of comparing the difference to a predetermine value to determine if the difference is greater than the predetermined value.

5. The method according to claim 1, where the acts of opening the value and closing the valve each includes an act of actuating the valve.

6. The method according to claim 1, further comprising an act of actuating the valve to transition from the open valve position to the closed valve position.

7. The method according to claim 1, wherein the first pressure measurement is determined by taking a first set of a plurality of measurements of a pressure transducer.

8. The method according to claim 7, wherein the first set of the plurality of measurements occur at predetermined intervals.

9. The method according to claim 7, wherein the second pressure measurement is determined by taking a second set of a plurality of measurements of the pressure transducer.

10. The method according to claim 9, wherein the second set of the plurality of measurements occur at the predetermined intervals.

11. The method according to claim 1, wherein the first and second measurements are temporally different.

12. The method according to claim 1, further comprising the act of continuously monitoring the pressure of the pressure tank.

13. The method according to claim 1, wherein the determining acts are calculating acts performed by at least one processor.

14. The method according to claim 1, further comprising the act of halting an operation of a dialysis machine when the difference is above the threshold.

15. The method according to claim 1, wherein the membrane is determined to be leaking if the difference is above the threshold.

16. A method for performing a dry integrity test on a disposable cassette that is configured to be used on a medical fluid handling system, the method comprising:

receiving a pressure on a membrane of the cassette;

measuring a first pressure associated with the membrane;

allowing a predetermined amount of time to pass;

measuring a second pressure associated with the membrane;

determining a difference between the first and second pressures; and

determining whether the difference is above a predetermined threshold.

17. The method according to claim 16, wherein the method further comprises determining the cassette has a leak if the difference is above the predetermined threshold.

18. The method according claim 16, wherein the method is configured to have a greater difference as a leak in the membrane is larger.

19. A method for detecting a leakage rate of fluid through a medical grade membrane in a fluid flow control system having a first chamber and a second chamber, the membrane being disposed between the first chamber and the second chamber, the second chamber having a connection to a pressure tank, the pressure tank having a fluid with a pressure, the connection defining a fluid path, the method comprising:

blocking the fluid path;

adjusting the pressure of the fluid in the pressure tank;

measuring a first pressure in the pressure tank to generate a first pressure value while the fluid path is blocked and after the pressure in the pressure tank is adjusted;

unblocking the fluid path;

measuring a second pressure in the pressure tank to generate a second pressure value after the fluid path is unblocked; and

determining whether there is a leak in the membrane based on a difference between the first pressure and the second pressure.

20. A method for detecting a leakage rate of fluid through a medical membrane in a fluid flow control medical system having a first chamber and a second chamber, the membrane being disposed between the first chamber and the second chamber, the second chamber having a medical-grade connection to a pressure tank, the pressure tank having a fluid with a pressure, the connection defining a medical-grade fluid path, the method comprising:

blocking the fluid path;

adjusting the pressure of the fluid in the pressure tank;

measuring a first pressure in the pressure tank to generate a first pressure value while the fluid path is blocked and after the pressure in the pressure tank is adjusted;

unblocking the fluid path;

measuring a second pressure in the pressure tank to generate a second pressure value after the fluid path is unblocked; and

determining a leakage of fluid through the membrane based on the first and second pressure values.

21. The method according to claim 20, further comprising the act of causing an alarm when the leakage becomes greater than a predetermined threshold value.

22. The method according to claim 21, wherein the step of causing an alarm occurs in a processor.

23. The method according to claim 21, wherein the alarm is an auditory alarm.

24. The method according to claim 21, wherein the alarm is a visual alarm.

25. The method according to claim 20, wherein in the act of measuring a pressure at a first set of multiple timed intervals and in the act of measuring a pressure at a second set of multiple timed intervals the pressure is measured with a transducer.

26. The method according to claim 20, wherein in the act of calculating a blocked pressure rate and in the act of calculating an unblocked pressure rate the rates are calculated in a processor.

27. The method according to claim 20, wherein the fluid is air.

28. The method according to claim 20, further comprising the acts of:

measuring the pressure at a first set of multiple timed intervals; and

storing each of the pressure measurements in a memory unit; and

providing the pressure measurements in the memory unit to a processor.

29. The method according to claim 20, further comprising the acts of:

measuring the pressure at a second set of multiple timed intervals;

storing each of the pressure measurements in a memory unit; and

providing the pressure measurements in the memory unit to a processor.

30. A method implemented by a medical computer system for detecting a leakage rate of fluid through a membrane in a fluid flow control system having a first chamber and a second chamber, the membrane disposed between the first chamber and the second chamber, the second chamber having a connection to a pressure tank, the pressure tank having a fluid with a pressure, the connection defining a fluid path, the method implemented by executing a set of instructions on the medical computer, the method performing the acts of:

activating, using the medical computer, a valve controller for blocking the fluid path;

adjusting, using the medical computer, the pressure of the fluid in the pressure tank;

reading, using the medical computer, the pressure in the pressure tank while the fluid path is blocked;

creating, using the medical computer, a pressure measurement at each of a first set of multiple timed intervals while the fluid path is blocked and after the pressure is adjusted;

calculating, using the medical computer, a blocked pressure value based on the pressure measurements in the pressure tank at the first set of multiple timed intervals;

activating, using the medical computer, the valve controller unblocking the fluid path;

reading, using the medical computer, the pressure within the pressure tank while the fluid path is unblocked;

creating, using the medical computer, a pressure measurement at each of a second set of multiple timed intervals after the fluid path is unblocked;

calculating, using the medical computer, an unblocked pressure value based on the pressure measurements in the pressure tank at the second set of multiple timed intervals; and

calculating, using the medical computer, a leakage rate based on the blocked pressure value and the unblocked pressure value.

31. The method according to claim 30, wherein the blocked pressure value and the unblocked pressure value are pressure measurements.

32. The method according to claim 30, further comprising the act of alarming the medical computer when the leakage rate becomes greater than a predetermined threshold value.

33. The method according to claim 30, further comprising the act of causing an alarm to be an auditory alarm.

34. The method according to claim 30, further comprising an act of causing an alarm to be a visual alarm.

35. A method for detecting a leakage rate of fluid through a membrane in a fluid flow control system having a first chamber and a second chamber, the membrane being disposed between the first chamber and the second chamber, the second chamber having a connection to a pressure tank, the pressure tank having a fluid with a pressure, the connection defining a fluid path, the method comprising:

blocking the fluid path;

adjusting the pressure of the fluid in the pressure tank;

taking a first measurement of the pressure within the pressure tank after the pressure tank is adjusted and the fluid path is blocked;

unblocking the fluid path;

taking a second measurement of the pressure within the pressure tank after the fluid path is unblocked;

taking the difference between the first and second measurements; and

determining whether the difference is above a threshold.

36. The method according to claim 35, wherein the second measurement occurs at a predetermined amount of time after the first measurement thereby defining a leak rate.

37. The method according to claim 35, wherein the act of determining whether the difference is above a threshold is determining whether a leak rate is past a critical leak rate.

38. The method according to claim 35, further comprising the act of causing an alarm when the leakage becomes greater than a predetermined threshold value.

39. The method according to claim 38, wherein the act of causing an alarm occurs in a processor.

40. The method according to claim 38, wherein the alarm is an auditory alarm.

41. The method according to claim 38, wherein the alarm is a visual alarm.

42. The method according to claim 35, wherein in the acts of taking a first measurement of the pressure includes an act of measuring a pressure at a first set of multiple timed intervals and, the act of taking a second measurement includes the act of measuring a pressure at a second set of multiple timed intervals the pressure.

43. The method according to claim 42, wherein the act of taking the first and second measurements utilizes a pressure transducer.

44. The method according to claim 35, wherein in the act of taking a first measurement and in the act of taking a second measurement are at least partially implemented by a calculation of a processor.

45. The method according to claim 35, wherein the fluid is air.

46. The method according to claim 35, further comprising the act of:

taking the first measurement using a first set of multiple timed intervals; and

storing each of the pressure measurements in a memory unit; and

providing the pressure measurements in the memory unit to a processor.

47. The method according to claim 35, further comprising the act of taking the second measurement using a second set of multiple timed intervals;

storing each of the pressure measurements in a memory unit;

providing the pressure multiplied timed interval measurements to the processor; and

calculating, by the processor, the first and second measurements.

48. A method for performing a dry integrity test on a medical-grade cassette, the method comprising:

adjusting a pressure of a pressure tank;

adjusting a valve connecting the pressure tank to a membrane of a cassette to a first position;

measuring a first pressure of the pressure tank after the valve has been in the first position;

adjusting the valve to a second position;

measuring a second pressure of the pressure tank after the valve has been in the second position;

determining a difference between the first and second pressures; and

determining whether the membrane is leaking above a threshold using the difference.

49. The method according to claim 48, wherein the method is implemented by one or more processors within a medical apparatus.

50. The method according to claim 48, wherein the cassette is loaded into a dialysis machine, wherein the dialysis machine performs the method.

51. The method according to claim 48, wherein the act of measuring the first pressure occurs while the valve still remains in the first position.

52. The method according to claim 48, wherein the act of measuring the second pressure occurs while the valve still remains in the second position.

53. A method for performing a dry integrity test on a medical-grade cassette, the method comprising:

adjusting a pressure of a pressure tank;

adjusting a valve connecting the pressure tank to a membrane of a cassette to a first position;

measuring a first pressure of the pressure tank after the valve has been in the first position;

adjusting the valve to a second position;

measuring a second pressure of the pressure tank after the valve has been in the second position;

determining a difference between the first and second pressures; and

determining whether there is a leak in the membrane based on the difference between the first and second pressures.

54. The method according to claim 53, wherein the determination of whether there is a leak in the membrane includes the act of determining whether the difference is beyond a threshold.