Pulsatile flow generation in heart-lung machines

• US 5,916,191 A
• Filed: 04/30/1996
• Issued: 06/29/1999
• Est. Priority Date: 04/30/1996
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Plunkett, Sean D., Palermo, Henry W.
• Primary Examiner(s): Clarke, Robert A.
• Assistant Examiner(s): O YONG, KI
• Application Number:
  US08/643,123
• Time in Patent Office: 1,155 Days
• Field of Search: 604/4-6, 604/65, 623/3, 251/4, 251/5, 251/61.1, 128/DIG. 3, 128/DIG. 12, 422/44-46
• US Class Current: 604/6.11
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/06 Heartbeat rate only
• CPC Class Codes: A61M 60/113 in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/279 Peristaltic pumps, e.g. roller pumps
• CPC Class Codes: A61M 60/37 Haemodialysis, haemofiltration or diafiltration
• CPC Class Codes: A61M 60/38 Blood oxygenation
• CPC Class Codes: A61M 60/446 the axis of both movements being parallel, e.g. roller screw actuators or cylindrical cam transmissions
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/554 of blood pressure
• CPC Class Codes: A61M 60/562 for making blood flow pulsatile in blood pumps that do not intrinsically create pulsatile flow
• CPC Class Codes: A61M 60/569 synchronous with the native heart beat

Abstract

Pulsatile blood flow in a heart-lung machine is accomplished by pumping blood into a bladder at a constant rate, and cyclically emptying the bladder into aortic line of the heart-lung machine either by means of the bladder'"'"'s own elasticity or by a mechanical compression mechanism which can be programmed to simulate the human heartbeat.

Claims

1. Apparatus for producing pulsatile blood flow in a heart-lung machine, comprising:

a) an extracorporeal blood circuit having an expandable bladder;

b) a blood intake connected to said bladder

c) a pump connected to said extracorporeal blood circuit, said pump pumping a supply of blood to said bladder at a substantially constant rate;

d) a blood outlet for said bladder; and

e) a pressure-sensitive valve having a hysteresis so as to open said blood outlet when the blood volume in said bladder rises to a first predetermined level, and to close said blood outlet when the blood volume in said bladder drops to a second predeteremined level.

2. The apparatus of claim 1, in which said bladder is elastic, and said elasticity provides the sole bias for ejecting blood into said blood outlet when said valve is open.

3. The apparatus of claim 1, further comprising:

e) a fixed plate and a movable plate, said bladder being disposed between said plates so as to be squeezable thereby; and

f) a controller arranged to operate said valve and to move said movable plate to squeeze said bladder while said valve is open;

g) a microprocessor associated with said controller and arranged to control the squeezing movement of said movable plate in such a manner as to squeeze said bladder in a predetermined pattern;

h) a pressure sensor in said blood outlet, said pressure sensor being so connected to said microprocessor in a feedback loop as to conform the blood pressure in said blood outlet to a predetermined time-amplitude pattern.