Device and methods for body fluid flow control in extracorporeal fluid treatments

• US 20040050789A1
• Filed: 07/28/2003
• Published: 03/18/2004
• Est. Priority Date: 10/12/2000
• Status: Active Grant

• Current Assignee: Renal Solutions, Inc. (Fresenius Medical Care AG)
• Original Assignee: Renal Solutions, Inc. (Fresenius Medical Care AG)
• Inventors: Ash, Stephen R.
• Granted Patent: US 7,273,465 B2
• Time in Patent Office: Days
• US Class Current: 210/646
• CPC Class Codes: A61M 1/3621 Extra-corporeal blood circuits single-needle circuits A61M1/30
• CPC Class Codes: A61M 1/3663 Flow rate transducers; Flow integrators
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 60/113 in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/37 Haemodialysis, haemofiltration or diafiltration
• CPC Class Codes: A61M 60/43 using vacuum at the blood pump, e.g. to accelerate filling
• CPC Class Codes: A61M 60/435 with diastole or systole switching by valve means located between the blood pump and the hydraulic or pneumatic energy source
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed

Abstract

Disclosed are devices and methods for the control of body fluid flow in the extracorporeal treatment of body fluid. Body fluid flow through on of a body fluid flow circuit (10, 50, 60, 100 or 250) is controlled by alternating applying vacuum pressure and positive pressure to the circuit through a pumping chamber (30, 51, 66, 102, or 200) coordinated with flow control valves (40, 42, 44, 62, 114, 116, 118, and 120) to effect a net downstream flow of body fluid through the circuit.

Claims

1. A body fluid pumping assembly for a fluid flow circuit, said assembly comprising:

a first chamber comprising a first expandable membrane therein and defining first body fluid chamber;

a first body fluid port into the first body fluid chamber providing fluid communication with the fluid flow circuit; and

a first gaseous port into the first chamber;

a first sensor providing a first signal representative of the body fluid flow rate in the blood flow circuit; and

a control device responsive to the first signal and adapted to control blood flow into the first inner chamber.

2. The assembly of claim 1, comprising a vacuum source and a pressure source provided to alternatively evacuate and pressurize the first chamber through the gaseous port.

3. The assembly of claim 2, wherein the control device comprises a valve responsive to the first signal to control gaseous flow into or out of the first gaseous port.

4. The assembly of claim 2 wherein the pressure in the first chamber alternates between a pre-selected first pressure and a pre-selected second pressure.

5. The pressure assembly of claim 4 wherein the pre-selected first pressure is selected to be between about −

200 and about −

300 mm of Hg and the pre-selected second pressure is selected to be between about +200 and about +300 mm of Hg.

6. The assembly of claim 1 wherein the first sensor is selected from the group consisting of:

optical detectors, ultrasonic detectors, and more specifically transit time ultrasonic detectors.

7. The assembly of claim 1 wherein the control device comprises a valve directing body fluid into the first body fluid chamber.

8. The assembly of claim 7 wherein the valve opens in response to first signal representative of a pre-determined body fluid flow rate change.

9. The assembly of claim 7 wherein the valve is positioned between the first body fluid and the body fluid flow circuit.

10. The assembly of claim 7, wherein the control device comprises a second valve responsive to the first signal to control gaseous flow into or out of the first gaseous port.

11. The assembly of claim 1 wherein the inner chamber comprises a second body fluid port providing fluid communication with the fluid flow circuit.

12. The assembly of claim 11 comprising a valve positioned between the second body fluid port and the body fluid flow circuit.

13. The assembly of claim 12 comprising a third valve adapted to vary the pressure in the first chamber between about —

300 mm of Hg and about +300 of Hg.

14. The assembly of claim 1 comprising a second chamber comprising a second expandable membrane therein and defining second body fluid chamber;

a second body fluid port into the second inner chamber; and

a second gaseous port into the second gaseous chamber.

15. The assembly of claim 14 wherein the control device comprises a one or more valves alternately directing body fluid flow into the first body fluid chamber and the second body fluid chamber.

16. The assembly of claim 14 wherein the control device comprises a one or more valves simultaneously allowing body fluid into the first body fluid chamber and the second body fluid chamber.

17. The assembly of claim 14 wherein the control device comprises one or more valves controlling alternate pressurization of the first and second gaseous chambers and alternate evacuation of the first and second chambers.

18. The assembly of claim 17 wherein the control device comprises a one or more valves alternately allowing body fluid to the first inner chamber and the second gaseous chamber.

19. The assembly of claim 1 wherein the fluid circuit comprises hemodialysis system, a plasmafiltration or hemofiltration system.

20. An extracorporeal body fluid treatment device comprising:

a body fluid treatment unit having a body fluid flow circuit therethrough including a body fluid inflow line and a body fluid outflow line;

a pumping assembly comprising a first pumping chamber in communication with said body fluid flow circuit and configured to alternately draw body fluid in under a predetermined vacuum pressure and push body fluid out under a predetermined positive pressure;

sensor for detecting the body fluid flow rate in the body fluid flow circuit; and

means for effecting the first pumping chamber to alternately draw body fluid in and push body fluid out.

21. The device of claim 20, wherein the body fluid treatment unit is a hemodialysis system, a plasmafiltration or a hemofiltration system.

22. The device of claim 20, wherein the predetermined vacuum pressure is between about —

300 and about −

200 mm of Hg and the predetermined positive pressure is between about 200 and about 300 mm of Hg.

23. The device of claim 20, wherein the first pumping chamber is coupled to the second pumping chamber whereby the first pumping chamber draws body fluid in while the second pumping chamber forces body fluid out.

24. The device of claim 20, wherein the pumping assembly is positioned upstream of body fluid treatment unit.

25. The device of claim 20, wherein the pumping assembly is positioned downstream of body fluid treatment unit.

26. The device of claim 20, comprising at least on control valve in fluid communication with the body fluid flow circuit and configured to effect a net downstream flow through the body fluid flow circuit.

27. The device of claim 20, wherein the pumping chamber is coupled to the body fluid flow circuit by a pumping chamber inlet line;

wherein the at least one flow control valve comprises a flow directional switching valve coupled to the flow circuit at the juncture of pumping chamber inlet line with the body fluid inflow line, and wherein the valve is configured to be controlled in a manner coordinated with said pumping chamber to effect a net downstream flow through said body fluid flow circuit.

28. The device of claim 20, wherein the pumping chamber comprises a flexible, fluid impermeable membrane, defining a body fluid chamber in fluid communication with said body fluid flow circuit, said membrane being positioned within an outer housing having a port to a source of vacuum pressure and a source of positive pressure, such that said membrane will expand when vacuum pressure is drawn on said housing, thereby communicating said vacuum pressure to said body fluid flow circuit, and such that said membrane will be compressed when positive pressure is applied to said housing, thereby communicating said positive pressure to said body fluid flow circuit.

29. The device of claim 28, wherein the predetermined vacuum pressure is between about —

300 and about −

200 mm of Hg and the predetermined positive pressure is between about 200 and about 300 mm of Hg.

30. The device of claim 20 wherein the sensor is selected from the group consisting of:

optical detectors, ultrasonic detectors, and trans-sonic detectors.

31. A body fluid pumping assembly comprising:

a fluid flow circuit;

a first chamber comprising a first membrane therein and defining first inner chamber;

a first body fluid port into the first body fluid chamber providing fluid communication with the fluid flow circuit; and

a first gaseous port for alternatively pressurizing and evacuating the first chamber;

a second chamber comprising a second membrane therein and defining second inner chamber;

a second body port into the second body fluid chamber providing fluid communication with the fluid flow circuit; and

a second gaseous port for alternatively pressurizing and evacuating the second chamber; and

a control unit synchronizing one or more valves controlling fluid flow with one or more valve controlling gaseous flow.

32. A method for providing a flow of a body fluid through a fluid flow circuit for extracorporeal treatment of the body fluid with a pumping assembly comprising a first pumping chamber having a first predetermined interior volume and in fluid communication with the fluid flow circuit, said method comprising:

withdrawing body fluid from an animal under a pre-selected vacuum pressure into the first pumping chamber to provide said chamber with a desired first amount of body fluid;

detecting a first flow rate of the body fluid; and

controlling the flow of body fluid in the fluid flow circuit in accordance with the first flow rate of the body fluid.

33. The method of claim 32, wherein said detecting comprises detecting the first flow rate of the body fluid directed to the first pumping chamber.

34. The method of claim 32, wherein controlling comprises expelling the first amount of body fluid from the first chamber when said first flow rate corresponds to a first pre-selected flow rate.

35. The method of claim 34, wherein the first pre-selected flow-rate is between about 400 ml/min and about 0 ml/minute.

36. The method of claim 34 wherein controlling comprises expelling the first amount of body fluid form the first chamber when the first flow rate decreases by at least 10%.

37. The method f claim 34 wherein controlling comprises alternately drawing body fluid in to the first pumping chamber under a predetermined vacuum pressure and push body fluid out of the first pumping chamber under a predetermined positive pressure.

38. The method of claim 37 wherein controlling comprises effecting alternatively withdrawing body fluid and pushing body fluid out of the chamber when the fluid flow rate decreases by at least 25%.

39. The method of claim 37 wherein controlling comprises effecting alternatively withdrawing body fluid and pushing body fluid out of the chamber when the fluid flow rate is between about 400 ml/minute and about 0 ml/minute.

40. The method of claim 32 wherein said pumping assembly comprises a second pumping chamber and said method comprises alternatively withdrawing body fluid into and pushing the body fluid out of the first and second pumping chambers.

41. The method of claim 40 wherein said controlling comprises withdrawing body fluid from the animal into the second pumping chamber when the first flow rate decreases by at least 10%.

42. The method of claim 40, wherein said controlling comprises withdrawing body fluid from the animal into the second pumping chamber when the first flow rate is between about 400 ml/minute and about 0 ml/minute.

43. The method of claim 40, wherein said controlling comprises expelling the first amount of body fluid from the first chamber when said first flow rate is between about 400 ml/minute and about 0 ml/minute.

44. The method of claim 40, wherein said detecting comprises determining the flow rate with one or more flow sensors selected from the group consisting of:

optical detectors, ultrasonic detectors, and trans-sonic detectors.

45. The method of claim 40 comprising detecting one or more flow rates of the body fluid out of the first chamber, the second chamber or both.

46. The method of claim 40 wherein said controlling comprises varying the pressure in the first chamber, the second chamber or both.

47. The method of claim 40 wherein said controlling comprises controlling one or more control valves to control body fluid flow into the first chamber, the second chamber or both.

48. The method of claim 47 wherein said controlling comprises varying the pressure in the first chamber, the second chamber or both.

49. The method of claim 32, wherein the extracorporeal body fluid treatment is hemodialysis, hemodialysis with a sorbent suspension, push-pull plasmapheresis, plasmafiltration, hemofiltration, or liver dialysis.

50. The method of claim 49, wherein the alternating vacuum and positive pressures are exerted on a pumping chamber such that the chamber fills with body fluid drawn from the patient under said exerted vacuum pressure, and said chamber empties of body fluid under said exerted positive pressure, and wherein at least one flow control valve coordinates with said alternating pressures to effect a net downstream body fluid flow through the body fluid flow circuit.