Pulsatile fluid delivery system

• US 20070134101A1
• Filed: 12/09/2005
• Published: 06/14/2007
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: Quest Medical Incorporated (Atrion Corporation)
• Original Assignee: Quest Medical Incorporated (Atrion Corporation)
• Inventors: Jones, Kenneth, Hayes, Richard, Corera, Cristo
• Granted Patent: US 7,842,003 B2
• Time in Patent Office: Days
• US Class Current: 417/44.100
• CPC Class Codes: F04B 49/065 and making use of computers

Abstract

A system for delivering blood, cardioplegia solution, and other medications or fluids in a pulsatile flow pattern to a patient during cardiopulmonary bypass is disclosed. In a preferred embodiment, a pumping apparatus having at least one chamber is utilized in which a pumping action is achieved by compressing one of the chambers with a piston mechanism, while allowing the other chamber to fill with fluid via retracting its respective piston. The instantaneous flow rate of either of the chambers is determined by the speed of the piston. In a preferred embodiment, a pulsatile flow of fluid is achieved by cyclically alternating the velocity of the piston between two different speeds. A desired average flow rate and/or delivery pressure and/or constant pulse pressure is maintained by adjusting the alternating velocities at the desired frequency and duty cycle. The calculations necessary to obtain a desired average flow rate are performed by a microprocessor, which also controls the movement of the pistons.

Claims

1. A method of creating a pulsatile flow of fluid into a biological destination, comprising:

providing a piston pump having at least one pump chamber containing fluid within the piston pump and adjacent to the piston; and

advancing the piston according to a time-varying velocity profile, wherein advancing the piston causes fluid to flow from the pump chamber to the biological destination at a flow rate that is related to a velocity of the piston.

2. The method of claim 1, wherein the flow rate is related quadratically to the velocity of the piston.

3. The method of claim 1, wherein the velocity of the piston produces a volumetric output rate between an upper and a lower output range.

4. The method of claim 3, wherein the velocity of the piston varies according to a rectangle-wave characteristic having a duty cycle.

5. The method of claim 4, further comprising:

receiving user input to specify the duty cycle for the rectangle-wave characteristic.

6. The method of claim 1, further comprising:

selecting the time-varying velocity profile so as to maintain a constant average flow rate or constant pulse pressure over time.

7. The method of claim 6, wherein selecting the time-varying velocity profile further comprises computing the time-varying velocity profile from a desired amplitude, a desired duty cycle, and a desired average flow rate.

8. The method of claim 7, wherein the time-varying velocity profile includes an upper flow rate and a lower flow rate, which are computed from the desired amplitude, desired duty cycle, and desired average flow rate.

9. The method of claim 7, further comprising:

obtaining user input to specify the desired amplitude, desired duty cycle, and desired average flow rate.

10. The method of claim 1, further comprising:

obtaining user input to specify a frequency for the time-varying velocity profile.

11. The method of claim 1, wherein the fluid pumped from the pump chamber passes through additional at least one additional apparatus before entering the biological destination.

12. The method of claim 11, wherein the at least one additional apparatus includes a compliant fluid delivery line.

13. The method of claim 11, wherein the at least one additional apparatus includes a heat exchanger.

14. The method of claim 1, wherein a flow rate of the fluid pumped from the pump chamber is independent of fluid pressure.

15. The method of claim 1, wherein the fluid includes at least one of blood, crystalloid solution, cardioplegia solution, and other medication.

16. The method of claim 1, wherein the biological destination is an organ.

17. The method of claim 14, wherein the organ is a heart.

18. The method of claim 1, wherein the biological destination is an organism.

19. The method of claim 18, wherein the organism is a human being.

20. The method of claim 1, wherein the piston contains a pressure sensor to determine pressure within the pump chamber.

21. A computer program product in a computer-readable medium for controlling delivery of fluids, comprising functional descriptive material that, when executed by a computer, causes the computer to perform actions that include:

controlling a piston pump having at least one pump chamber containing fluid within the piston pump and adjacent to the piston; and

advancing the piston according to a time-varying velocity profile, wherein advancing the piston causes fluid to flow from the pump chamber at a flow rate that is related to a velocity of the piston.

22. The computer program product of claim 21, wherein the flow rate is related quadratically to the velocity of the piston.

23. The computer program product of claim 21, wherein the velocity of the piston produces a volumetric output rate which alternates between an upper output rate and a lower output rate.

24. The computer program product of claim 23, wherein the velocity of the piston varies according to a rectangle-wave characteristic having a duty cycle.

25. The computer program product of claim 24, further comprising:

receiving user input to specify the duty cycle for the rectangle-wave characteristic.

26. The computer program product of claim 21, comprising additional functional descriptive material that, when executed by a computer, causes the computer to perform additional actions of:

selecting the time-varying velocity profile so as to maintain a constant average flow rate or constant pulse pressure over time.

27. The computer program product of claim 26, wherein selecting the time-varying velocity profile further comprises computing the time-varying velocity profile from a desired amplitude, a desired duty cycle, and a desired average flow rate.

28. The computer program product of claim 27, wherein the time-varying velocity profile includes an upper flow rate and a lower flow rate, which are computed from the desired amplitude, desired duty cycle, and desired average flow rate.

29. The computer program product of claim 27, comprising additional functional descriptive material that, when executed by a computer, causes the computer to perform additional actions of:

obtaining user input to specify the desired amplitude, desired duty cycle, and desired average flow rate.

30. The computer program product of claim 21, comprising additional functional descriptive material that, when executed by a computer, causes the computer to perform additional actions of:

obtaining user input to specify a frequency for the time-varying velocity profile.

31. A pulsatile fluid delivery system comprising:

a piston pump having at least one pump chamber containing fluid within the piston pump and adjacent to the piston; and

a control system configured to control operation of the piston pump, wherein the control system directs the piston to be advanced according to a time-varying velocity profile, wherein advancing the piston causes fluid to flow from the pump chamber to an biological destination at a flow rate that is related to a velocity of the piston.

32. The fluid delivery system of claim 31, wherein the control system includes a stored-program computer and the stored program computer controls the operation of the piston pump according to a stored program.

33. The fluid delivery system of claim 31, wherein the flow rate is related quadratically to the velocity of the piston.

34. The fluid delivery system of claim 31, wherein the velocity of the piston produces a volumetric output rate between an upper and a lower output rate.

35. The fluid delivery system of claim 34, wherein the velocity of the piston varies according to a rectangle-wave characteristic having a duty cycle.

36. The fluid delivery system of claim 35, further comprising:

a user input device, wherein the user input device receives user input to specify the duty cycle for the rectangle-wave characteristic.

37. The fluid delivery system of claim 31, wherein the control system selects the time-varying velocity profile so as to maintain a constant average flow rate or constant pulse pressure over time.

38. The fluid delivery system of claim 37, wherein selecting the time-varying velocity profile further comprises computing the time-varying velocity profile from a desired amplitude, a desired duty cycle, and a desired average flow rate.

39. The fluid delivery system of claim 38, wherein the time-varying velocity profile includes an upper flow rate and a lower flow rate, which are computed from the desired amplitude, desired duty cycle, and desired average flow rate.

40. The fluid delivery system of claim 38, further comprising:

a user input device, wherein the user input device obtains user input to specify the desired amplitude, desired duty cycle, and desired average flow rate.

41. The fluid delivery system of claim 31, further comprising:

a user input device, wherein the user input device obtains user input to specify a frequency for the time-varying velocity profile.

42. The fluid delivery system of claim 31, wherein the fluid pumped from the pump chamber passes through additional at least one additional apparatus before entering the biological destination.

43. The fluid delivery system of claim 42, wherein the at least one additional apparatus includes a compliant fluid delivery line.

44. The fluid delivery system of claim 42, wherein the at least one additional apparatus includes a heat exchanger.

45. The fluid delivery system of claim 31, wherein a flow rate of the fluid pumped from the pump chamber is independent of fluid pressure.

46. The fluid delivery system of claim 31, wherein the fluid includes at least one of blood, crystalloid solution, cardioplegia solution, and other medication.

47. The fluid delivery system of claim 31, wherein the biological destination is an organ.

48. The fluid delivery system of claim 47, wherein the organ is a heart.

49. The fluid delivery system of claim 31, wherein the biological destination is an organism.

50. The fluid delivery system of claim 49, wherein the organism is a human being.

51. The fluid delivery system of claim 31, wherein the piston contains a pressure sensor to determine pressure within the pump chamber.