Blood pump flow rate control method and apparatus utilizing multiple sensors

• US 6,422,990 B1
• Filed: 07/28/2000
• Issued: 07/23/2002
• Est. Priority Date: 11/26/1997
• Status: Expired due to Fees

• Current Assignee: Vascor, Inc.
• Original Assignee: Vascor, Inc.
• Inventors: Prem, Edward K.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/627,864
• Time in Patent Office: 725 Days
• Field of Search: 600/17, 600/16, 600/507, 600/587, 600/407, 600/438, 600/439, 600/459, 600/449, 600/450, 600/465, 623/3.1, 623/3.28, 623/3.13
• US Class Current: 600/17
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/523 using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed
• 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 60/82 Magnetic bearings
• CPC Class Codes: A61M 60/824 Hydrodynamic or fluid film bearings
• CPC Class Codes: A61M 60/833 Occluders for preventing backflow
• CPC Class Codes: A61M 60/894 Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: F04D 13/0646 the hollow pump or motor shaft being the conduit for the working fluid
• CPC Class Codes: F04D 29/048 magnetic; electromagnetic
• CPC Class Codes: F16C 2316/18 Pumps for pumping blood
• CPC Class Codes: F16C 2360/44 Centrifugal pumps in general F04D
• CPC Class Codes: F16C 32/0444 Details of devices to control the actuation of the electromagnets

Abstract

A flow rate control method and apparatus for a blood pump is provided wherein multiple sensors are utilized to measure physical dimensions of a ventricle to calculate either a cross sectional area or a volume of the ventricle during distention and contraction. The multiple sensors are positioned at spaced locations around the ventricle, and may be attached to or imbedded in the ventricle. The sensors may be in the same plane for determining a cross sectional area or in different planes for determining a volume. The area or volume is generally proportional to a corresponding area or volume of the ventricle such that the calculated area or volume is indicative of distention and contraction of the volume. The area or volume is utilized to control the blood pump flow rate to avoid overly distending or contracting the ventricle and for operating the flow rate in a pulsatile manner to closely approximate the natural pumping action of the heart.

Claims

1. An method of controlling a blood pump flow rate comprising:

a. measuring physical dimensions of a ventricle during at least one of distention and contraction thereof;

b. calculating at least one of an area and a volume using said physical dimensions, said at least one of an area and a volume generally proportional to a corresponding area or volume of said ventricle;

c. said at least one of an area and a volume indicative of said at least one of distention and contraction of said ventricle; and

d. controlling said blood pump flow rate based on at least one of said area and said volume.

2. The method of claim 1 further comprising controlling said blood pump flow rate to produce a pulsatile flow rate.

3. The method of claim 1 wherein said measuring further comprises ultrasonically measuring a plurality of dimensions of said ventricle.

4. The method of claim 3 wherein said plurality of dimensions further comprises at least three dimensions measured in a single plane through said ventricle such that a cross sectional area is calculated.

5. The method of claim 3 wherein said plurality of dimensions are measured in more than one plane through said ventricle such that a volume is calculated.

6. An apparatus for operating a blood pump at a controlled flow rate comprising:

a. a flow rate controller controlling said blood pump to pump blood at a flow rate;

b. a heart measurement member operatively associated with said flow rate controller and said heart measurement member attachable to a ventricle of a heart which is assisted by said blood pump;

c. said heart measurement member determining at least one of an area and a volume during at least one of distention and contraction of said ventricle, said at least one of an area and a volume being proportional to a corresponding area or volume of said ventricle during said at least one of distention and contraction; and

d. said flow rate controller utilizing at least one of said area and said volume to control said flow rate.

7. The apparatus of claim 6 wherein said flow rate is a pulsatile flow rate.

8. The apparatus of claim 6 wherein said heart measurement member comprises:

a. a plurality of ultrasonic transducers positioned at radially spaced apart locations on said ventricle; and

b. said heart measurement member measuring distances between each of said plurality of ultrasonic transducers, said distances utilized to determine at least one of said area and said volume, said distances based upon an elapsed time for an ultrasonic pulse to travel between respective ones of said plurality of ultrasonic transducers.

9. The apparatus of claim 8 wherein said plurality of ultrasonic transducers further comprises at least three ultrasonic transducers positioned in a single plane through said ventricle such that a cross sectional area may be determined.

10. The apparatus of claim 8 wherein said plurality of ultrasonic transducers are positioned in at least two planes through said ventricle such that a volume may be determined.