MEDICAL FLUID CASSETTES AND RELATED SYSTEMS AND METHODS

• US 20130331774A1
• Filed: 06/08/2012
• Published: 12/12/2013
• Est. Priority Date: 06/08/2012
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Inventors: Farrell, Sean, Fallon, Joseph Michael, Plahey, Kulwinder S., Beiriger, Michael James
• Granted Patent: US 9,610,392 B2
• Time in Patent Office: Days
• US Class Current: 604/28
• 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 1/155 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 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/121 interface between cassette and base
• CPC Class Codes: A61M 2205/36 related to heating or cooling
• CPC Class Codes: A61M 2209/084 Supporting bases, stands for equipment
• CPC Class Codes: F04B 43/025 two or more plate-like pumping members in parallel
• 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: F04B 9/02 the means being mechanical

Abstract

This disclosure relates to medical fluid cassettes and related systems and methods. In certain aspects, a medical fluid cassette includes a base having a first region and a second region, a first membrane overlying the first region of the base, and a second membrane overlying the second region of the base. The second membrane is configured to rebound away from the base when a force used to press the second membrane toward the base is released.

Claims

1. A medical fluid pumping system, comprising:

a medical fluid pumping machine defining a cassette enclosure, the medical fluid pumping machine comprising a movable piston; and

a medical fluid cassette configured to be disposed within the cassette enclosure of the medical fluid pumping machine, the medical fluid cassette comprising

a base having a first region and a second region;

a first membrane overlying the first region of the base, the first membrane cooperating with the first region of the base to form at least one fluid pathway; and

a second membrane overlying the second region of the base, the second membrane cooperating with the second region of the base to define a fluid pump chamber, the second membrane being more resilient than the first membrane, and the cassette being positionable within the cassette enclosure of the medical fluid pumping machine so that the second membrane can be moved toward the base by the piston to decrease a volume of the fluid pump chamber and, upon retraction of the piston, the second membrane can rebound to increase the volume of the pump chamber.

2. The medical fluid pumping system of claim 1, wherein the second region of the base is a recessed region of the base.

4. The medical fluid pumping system of claim 1, wherein the second membrane has a greater thickness than the first membrane.

6. The medical fluid pumping system of claim 1, wherein the first and second membranes are formed of different materials.

8. The medical fluid pumping system of claim 1, wherein the second region of the base is a recessed region of the base, and the second membrane is sized to overlie a portion of the base that surrounds the recessed region.

9. The medical fluid pumping system of claim 8, wherein a fluid-tight seal is formed between a peripheral region of the second membrane and the base.

10. The medical fluid pumping system of claim 9, wherein the second membrane comprises a dome-shaped portion.

11. The medical fluid pumping system of claim 9, wherein the medical fluid cassette further comprises a first ring that is secured to the second membrane and compresses the second membrane against the base.

12. The medical fluid pumping system of claim 11, wherein the first ring is fastened to the base.

13. The medical fluid pumping system of claim 11, further comprising a second ring disposed on a side of the base opposite the second membrane, the second ring secured to the first ring in a manner to cause the first ring to compress the second membrane against the base.

15. The medical fluid pumping system of claim 9, wherein the second membrane is attached to the portion of the base that surrounds the recessed region.

17. The medical fluid pumping system of claim 1, wherein the first membrane defines an aperture that is aligned with the second region of the base, and the second membrane is at least partially disposed within the aperture of the first membrane.

18. The medical fluid pumping system of claim 1, wherein the first membrane covers substantially the entire surface of the base.

20. The medical fluid pumping system of claim 18, wherein the second membrane is attached to a portion of the first membrane that overlies the second region of the base.

21. The medical fluid pumping system of claim 18, wherein the second membrane overlies substantially the entire surface of the base.

22. The medical fluid pumping system of claim 21, wherein the second membrane comprises a plurality of cutouts that are aligned with valve regions of the cassette.

24. The medical fluid pumping system of claim 1, wherein the piston comprises a piston head having a circumferential region that is configured to move radially inward as the piston head is pressed against the second membrane to move the second membrane toward the base.

25. The medical fluid pumping system of claim 24, wherein the circumferential region of the piston head is formed of an elastomeric material that compresses as the piston head is pressed against the second membrane to move the second membrane toward the base.

26. The medical fluid pumping system of claim 24, wherein the piston head comprises a plurality of interleaved segments that move relative to one another to allow the circumferential region of the piston head to collapse as the piston head is pressed against the second membrane to move the second membrane toward the base.

29. The medical fluid pumping system of claim 24, wherein the piston head comprises a plurality of telescoping segments that move relative to one another to allow the circumferential region of the piston head to collapse as the piston head is pressed against the second membrane to move the second membrane toward the base.

32. The medical fluid pumping system of claim 24, wherein at any given time throughout an outward stroke of the piston, an area of a portion of the piston head in contact with the second membrane is substantially equal to an area of the pump chamber in a plane in which the second membrane lies.

33. The medical fluid pumping system of claim 1, wherein the medical fluid pumping system is a dialysis system.

34. The medical fluid pumping system of claim 33, wherein the medical fluid pumping system is a peritoneal dialysis system.

3. (canceled)

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14. (canceled)

16. (canceled)

19. (canceled)

23. (canceled)

27-28. -28. (canceled)

30-31. -31. (canceled)

35. A medical fluid cassette, comprising:

a base having a first region and a second region;

a first membrane overlying the first region of the base, the first membrane cooperating with the first region of the base to form at least one fluid pathway; and

a second membrane overlying the second region of the base, the second membrane cooperating with the second region of the base to define a fluid pump chamber, the second membrane being more resilient than the first membrane and being configured to rebound away from the base when a force used to press the second membrane toward the base is released.

42. The medical fluid cassette of claim 35, wherein the second region of the base is a recessed region of the base, and the second membrane is sized to overlie a portion of the base that surrounds the recessed region.

43. The medical fluid cassette of claim 42, wherein a fluid-tight seal is formed between a peripheral region of the second membrane and the base.

44. The medical fluid cassette of claim 43, wherein the second membrane comprises a dome-shaped portion.

45. The medical fluid cassette of claim 43, wherein the medical fluid cassette further comprises a first ring that is secured to the second membrane and compresses the second membrane against the base.

47. The medical fluid cassette of claim 45, further comprising a second ring disposed on a side of the base opposite the second membrane, the second ring secured to the first ring in a manner to cause the first ring to compress the second membrane against the base.

49. The medical fluid cassette of claim 43, wherein the second membrane is attached to the portion of the base that surrounds the recessed region.

51. The medical fluid cassette of claim 35, wherein the first membrane defines an aperture that is aligned with the second region of the base, and the second membrane is at least partially disposed within the aperture of the first membrane.

52. The medical fluid cassette of claim 35, wherein the first membrane covers substantially the entire surface of the base.

54. The medical fluid cassette of claim 52, wherein the second membrane is attached to a portion of the first membrane that overlies the second region of the base.

56. The medical fluid cassette of claim 52, wherein the second membrane overlies substantially the entire surface of the base.

57. The medical fluid cassette of claim 56, wherein the second membrane comprises a plurality of cutouts that are aligned with valve regions of the cassette.

59. The medical fluid cassette of claim 35, wherein the medical fluid cassette is a dialysis fluid cassette.

60. The medical fluid cassette of claim 59, wherein the medical fluid cassette is a peritoneal dialysis fluid cassette.

36-41. -41. (canceled)

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61. A medical fluid delivery method, comprising:

expelling a medical fluid from a fluid pump chamber defined between a membrane and a recessed region of a base of a medical fluid cassette by using a piston to press the membrane into the recessed region; and

then

drawing medical fluid into the fluid pump chamber by retracting the piston and allowing the membrane to rebound toward the retracting piston, wherein the membrane is allowed to rebound toward the retracting piston head due to resiliency of the membrane.

62-65. -65. (canceled)

66. A medical fluid pumping machine, comprising:

a housing that at least partially defines a cassette enclosure configured to receive a medical fluid cassette comprising a fluid pump chamber defined between a membrane and a base; and

a piston that is translatable relative to the housing, the piston comprising a piston head having a circumferential region that is configured to move radially inward as the piston head is pressed against the membrane of the cassette to move the membrane toward the base of the cassette.

67-75. -75. (canceled)

76. A medical fluid delivery method, comprising:

expelling a medical fluid from a fluid pump chamber defined between a membrane and a base of a medical fluid cassette by pressing a piston head against the membrane to move the membrane toward the base, wherein a circumferential region of the piston head is configured to move radially inward as the piston head is pressed against the membrane to move the membrane toward the base.

77-78. -78. (canceled)