Pressure/flow characteristic modification of a centrifugal pump in a ventricular assist device

• US 10,117,983 B2
• Filed: 11/15/2016
• Issued: 11/06/2018
• Est. Priority Date: 11/16/2015
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Inventors: Medvedev, Alexander, Sami, Muhammad
• Primary Examiner(s): Bertram, Eric D.
• Application Number:
  US15/352,141
• Publication Number:
  US 20170136163A1
• Time in Patent Office: 721 Days
• 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 60/411 generated by an electromotor
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed
• CPC Class Codes: A61M 60/585 User interfaces
• CPC Class Codes: F04D 13/06 the pump being electrically driven
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0088 Testing machines
• CPC Class Codes: F04D 29/22 specially for centrifugal pumps
• CPC Class Codes: F05D 2270/3061 of the working fluid

Abstract

A ventricular assist device is disclosed. The ventricular assist device may include a centrifugal pump and a controller. The controller may be configured to cause the centrifugal pump to operate at a first speed above a predetermined flow rate. The controller may also be configured to cause the centrifugal pump to operate at a second speed below the predetermined flow rate, wherein the predetermined flowrate is indicative of a crossover point between systole and diastole phases of a person'"'"'s cardiac cycle.

Claims

1. A ventricular assist device comprising:

a centrifugal pump having a motor; and

a controller, wherein the controller is configured to at least;

measure a current of the motor;

determine an estimated flow rate through the centrifugal pump based on the current;

cause the motor of the centrifugal pump to operate at a first speed when the estimated flow rate is greater than a predetermined flow rate; and

cause the motor of the centrifugal pump to operate at a second speed when the estimated flow rate is less than the predetermined flow rate, wherein the predetermined flowrate is indicative of an actual flow rate through the pump at a crossover point between systole and diastole phases of a person'"'"'s cardiac cycle.

2. A method of controlling a centrifugal pump in a ventricular assist device of a person, wherein the method comprises:

measuring a current of a motor of a centrifugal pump in a ventricular assist device;

determining an estimated flow rate through the centrifugal pump based on the current;

causing the motor of the centrifugal pump to operate at a first speed when the estimated flow rate is greater than a predetermined flow rate; and

causing the motor of the centrifugal pump to operate at a second speed when the estimated flow rate is less than the predetermined flow rate, wherein the predetermined flowrate is indicative of an actual flow rate through the pump at a crossover point between systole and diastole phases of a person'"'"'s cardiac cycle.

3. The method of controlling a centrifugal pump of claim 2, wherein the first speed comprises a minimum operating speed as set by a clinician.

4. The method of controlling a centrifugal pump of claim 2, wherein the second speed is greater than the first speed.

5. The method of controlling a centrifugal pump of claim 2, wherein the second speed comprises a set speed as set by a clinician.

6. The method of controlling a centrifugal pump of claim 2, wherein when the motor of the centrifugal pump is operating at the second speed, the motor of the centrifugal pump is operating at a constant current.

7. The method of controlling a centrifugal pump of claim 2, wherein causing the motor of the centrifugal pump to operate at the second speed comprises controlling the motor of the centrifugal pump to maintain a parameter at a substantially constant value, wherein the parameter is selected from a group consisting of:

motor current, motor voltage, motor power, back electromotive force, and a combination of the same.

8. The method of controlling a centrifugal pump of claim 2, wherein the method further comprises:

determining a current flow rate with a flow measurement sensor.

9. The method of controlling a centrifugal pump of claim 8, wherein the method further comprises:

comparing the current flow rate to the predetermined flow rate.

10. The method of controlling a centrifugal pump of claim 2, wherein the predetermined flow rate is set by a clinician.

11. The method of controlling a centrifugal pump of claim 2, wherein the method further comprises:

identifying a suction event in the centrifugal pump and reducing a speed of the motor of the centrifugal pump to alleviate the suction event.

12. A controller for operating a centrifugal pump in a ventricular assist device of a person, wherein the controller comprises:

one or more processors configured to execute instructions stored on a non-transitory medium, the instructions executable by the one or more processors to at least;

measure a current of a motor of a centrifugal pump in a ventricular assist device;

determine an estimated flow rate through the centrifugal pump based on the current;

cause the motor of the centrifugal pump to operate at a first speed when the estimated flow rate is greater than a predetermined flow rate; and

cause the motor of the centrifugal pump to operate at a second speed when the estimated flow rate is less than the predetermined flow rate, wherein the predetermined flowrate is indicative of an actual flow rate through the pump at a crossover point between systole and diastole phases of a person'"'"'s cardiac cycle.

13. The controller for operating a centrifugal pump of claim 12, wherein the second speed is greater than the first speed.

14. A non-transitory machine readable medium having instructions stored thereon for operating a centrifugal pump in a ventricular assist device of a person, the instructions executable by one or more processors to at least:

measure a current of a motor of a centrifugal pump in a ventricular assist device;

determine an estimated flow rate through the centrifugal pump based on the current;

cause the motor of the centrifugal pump to operate at a first speed when the estimated flow rate is greater than a predetermined flow rate; and

cause the motor of the centrifugal pump to operate at a second speed when the estimated flow rate is less than the predetermined flow rate, wherein the predetermined flowrate is indicative of an actual flow rate through the pump at a crossover point between systole and diastole phases of a person'"'"'s cardiac cycle.

15. The non-transitory machine readable medium of claim 14, wherein the second speed is greater than the first speed.