Priming, integrity and head height methods and apparatuses for medical fluid systems

• US 20050126998A1
• Filed: 10/27/2004
• Published: 06/16/2005
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Childers, Robert W.
• Granted Patent: US 7,575,564 B2
• Time in Patent Office: Days
• US Class Current: 210/646
• CPC Class Codes: A61B 5/02042 Determining blood loss or bleeding, e.g. during a surgical procedure
• CPC Class Codes: A61M 1/1522 the interface being evacuated interfaces to enhance contact
• CPC Class Codes: A61M 1/1524 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/154 with sensing means or components thereof
• CPC Class Codes: A61M 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/1561 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 1/1565 Details of valves
• CPC Class Codes: A61M 1/159 specially adapted for peritoneal dialysis
• CPC Class Codes: A61M 1/28 Peritoneal dialysis ; Other peritoneal treatment, e.g. oxygenation
• CPC Class Codes: A61M 1/281 Instillation other than by gravity
• CPC Class Codes: A61M 1/284 Continuous flow peritoneal dialysis [CFPD]
• CPC Class Codes: A61M 1/288 Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 1/3621 Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 Mode of operation
• CPC Class Codes: A61M 1/3652 using gas, e.g. air
• CPC Class Codes: A61M 2205/122 using evacuated interfaces to enhance contact
• CPC Class Codes: A61M 2205/128 with incorporated valves
• CPC Class Codes: A61M 2205/70 : with testing or calibration facilities
• CPC Class Codes: G01L 7/00 : Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements G01L11/004 takes precedence; transmitting or indicating the displacement of mechanical pressure-sensitive elements by electric , e.g., photoelectric or magnetic means G01L9/00; measuring differences of two or more pressure values G01L13/00; measuring two or more pressure values simultaneously G01L15/00
• CPC Class Codes: G01M 3/04 : by detecting the presence of fluid at the leakage point

Abstract

Improved integrity test, priming sequence and bag height detection tests, apparatuses and methods for a medical fluid delivery system are provided. The integrity test includes a plurality of air pressure decay tests, using positive and negative pressure. The priming sequence includes pumping fluid through a portion of a patient line to be primed to overcome air in the line and other potential obstacles. The head height test measures a pressure build-up or drop-off within a pump chamber of a membrane pump. The measured pressure corresponds to a head height between a fluid supply and the pump or between the pump and a fluid drain. A determination is made whether the corresponding head height is acceptable.

Claims

1. A dialysis machine under control of a processor, the machine comprising:

an actuation unit configured to accept a disposable medical fluid cassette that includes a flexible membrane, the cassette arranged to receive a medical fluid;

the actuation unit and the processor operable to;

in a first integrity test, provide a positive pressure to an outer surface of the membrane of the cassette and measure a decay of the positive pressure on the outer surface; and

in a second integrity test, provide positive pressure to an inner surface of the membrane of the cassette and measure a decay of the positive pressure on the inner surface.

2. The dialysis machine of claim 1, wherein positive pressure is provided in at least one of the first and second tests via a pneumatic source or a mechanical device.

3. The dialysis machine of claim 2, which includes a sensor positioned at the pneumatic source to sense the decay of the positive pressure.

4. The dialysis machine of claim 1, wherein positive pressure in the second integrity test is applied to at least one portion of the cassette selected from the group consisting of:

a pumping portion, a valve portion, a port portion and a flow path portion.

5. The dialysis machine of claim 1, wherein positive pressure in the first integrity test is applied to a first portion of the outer surface of the membrane and negative pressure is applied to a second portion of the outer surface of the membrane.

6. The dialysis machine of claim 1, wherein positive pressure in the first integrity test is applied to a first portion of the outer surface of the membrane and negative pressure is applied to a second portion of the outer surface of the membrane.

7. The dialysis machine of claim 1, wherein positive pressure in the second integrity test is applied to a first portion of the inner surface of the membrane and negative pressure is applied to a second portion of the inner surface of the membrane.

8. The dialysis machine of claim 1, wherein the second integrity test is a first test in which pressure is applied to an inner surface of the membrane of the cassette and pressure decay is measured, and which includes at least one additional integrity test in which at least one of positive and negative pressure is applied to an inner surface of the membrane of the cassette and at least one of positive and negative pressure decay is measured.

9. The dialysis machine of claim 1, wherein the second test occurs after the first test.

10. The dialysis machine of claim 1, wherein at least one of the first and second tests triggers an alarm if the associated pressure decay is not compliant with a preset range.

11. The dialysis machine of claim 1, wherein a same pressure source is used to create positive pressure on the inner and outer surfaces of the membrane.

12. A dialysis machine under control of a processor, the machine comprising:

an actuation unit configured to accept a disposable medical fluid cassette, the cassette having a plurality of fluid lines, each of the fluid lines enclosed so that the sterility of air within the lines is maintained prior to use in treatment, the cassette arranged to receive a medical fluid; and

wherein the actuation unit and the processor are operable;

(i) to provide air pressure to an inner surface of the membrane of the cassette and (ii) to measure a decay of the pressure, (iii) while the fluid lines are enclosed and before any of the fluid lines is connected to a fluid supply.

13. The dialysis machine of claim 12, wherein at least one of the fluid lines is enclosed via at least one device selected from the group consisting of:

a tip protector, a line clamp, and a hydrophobic membrane.

14. The dialysis machine of claim 12, wherein the actuation unit and the processor are further operable:

(i) to provide pressure to the inner surface and (ii) to measure pressure decay, (iii) while at least one of the fluid lines is connected to the fluid supply.

15. The dialysis machine of claim 14, wherein the pressure applied while the at least one fluid line is connected to the fluid supply is air pressure or liquid pressure.

16. The dialysis machine of claim 12, wherein the pressure applied to the inner surface is at least one of positive air pressure and negative air pressure.

17. The dialysis machine of claim 16, wherein the positive and negative pressures are provided at the same time.

18. The dialysis machine of claim 12, wherein the pressure applied to the inner surface of the membrane is caused by applying a pressure to an outer surface of the membrane and manipulating at least one valve.

19. The dialysis machine of claim 12, wherein the pressure applied to the outer surface of the membrane is at least one of a positive pressure and a negative pressure.

20. The dialysis machine of claim 12, wherein the pressure is applied to a select portion of the cassette.

21. The dialysis machine of claim 12, wherein the processor is further operable to process an alarm signal if the measured pressure decay does not comply with a preset range.

22. An improved integrity test method for a dialysis machine having an actuation unit operable with a disposable cassette, the method comprising:

testing a pressure holding capacity of the cassette first; and

testing an operation of the actuation unit second so that a user can determine, after a test failure, whether the failure is due to a failure in the cassette or a failure in the actuation unit.

23. The method of claim 22, wherein testing the pressure holding capacity of the cassette includes performing a plurality of pressure decay tests.

24. The method of claim 22, wherein testing the pressure holding capacity of the cassette includes testing the pressure holding capacity of select portions of the cassette.

25. The method of claim 22, wherein testing the pressure holding capacity of the cassette includes performing a pressure decay test using at least one of positive and negative pressure.

26. The method of claim 22, wherein testing the holding capacity of the cassette includes performing a pressure decay test on pressure applied to at least one of an outside and an inside of the cassette.

27. The method of claim 22, wherein testing the operation of the actuation unit includes testing at least one of a cassette valve operation and a tubing occlusion operation.

28. A method of priming a fluid line in communication with a fluid pump and a fluid bag located upstream from the pump, the method comprising:

(a) pumping fluid through a portion of the fluid line; and

(b) enabling a remainder of the fluid line to be primed via gravity.

29. The method of claim 28, which includes setting a fluid level in the bag and a distal end of the fluid line at substantially the same elevational height.

30. The method of claim 28, which includes closing an outlet valve downstream of the pump while opening an inlet valve upstream of the pump and using the pump to draw fluid from the bag into a pump chamber of the pump.

31. The method of claim 30, which includes closing the inlet valve, opening the outlet valve, and pumping the fluid through the portion of the fluid line.

32. The method of claim 30, which includes opening the inlet and outlet valves and enabling fluid from the bag to be gravity fed to prime the reminder of the fluid line.

33. A method of priming a fluid line in communication with a fluid pump and a fluid bag located upstream from the pump, the method comprising:

(a) pumping fluid through a portion of the fluid line; and

(b) detecting that a patient clamp has not been removed properly from the fluid line by sensing a lack of an expected pressure drop upon pumping the fluid through the portion of the fluid line.

34. The method of claim 33, which includes overcoming air in the fluid line via the pumping of fluid through the portion of the fluid line.

35. A method of verifying head height for a medical fluid system that includes a fluid supply and a fluid pump, the fluid pump including a flexible membrane located inside a pump chamber, the method comprising:

(a) gravity filling at least a portion of the fluid pump with fluid from the supply, the fluid moving the flexible membrane within the chamber;

(b) measuring an air pressure in the chamber on an opposite side of the moved membrane from the fluid, the air pressure indicative of a head height of the supply; and

(c) determining if the head height is acceptable.

36. The method of claim 35, wherein the pump is a first pump and the fluid supply is a first fluid supply and which includes a second pump and a second fluid supply and performing procedures (a) to (c) for the second pump and second fluid supply.

37. The method of claim 35, which includes providing an alarm if the head height is not acceptable.

38. The method of claim 35, wherein measuring the air pressure in the chamber includes calibrating a pressure sensor when the air pressure on the opposite side of the membrane is expected to be zero.

39. A method of verifying head height for a medical fluid system that includes a fluid drain and a fluid pump, the fluid pump including a flexible membrane located inside a pump chamber, the method comprising:

(a) removing fluid from the fluid pump to the fluid drain via gravity, the fluid removal moving the flexible membrane within the chamber;

(b) measuring an air pressure in the chamber on an opposite side of the moved membrane from the fluid, the air pressure indicative of a head height between the fluid pump and the fluid drain; and

(c) determining if the head height is acceptable.

40. The method of claim 39, which includes providing an alarm if the head height is not acceptable.

41. The method of claim 39, wherein measuring the air pressure in the chamber includes calibrating a pressure sensor, prior to removing fluid from the fluid pump, when the air pressure on the opposite side of the membrane is expected to be zero.

42. The method of claim 39, wherein measuring the air pressure in the chamber includes measuring a negative air pressure.