Apparatus and method for modifying pressure-flow characteristics of a pump

• US 9,839,733 B2
• Filed: 06/22/2015
• Issued: 12/12/2017
• Est. Priority Date: 06/22/2010
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Inventors: Reichenbach, Steven H., Law, Yu Fai
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): Miller, Cheryl
• Application Number:
  US14/746,527
• Publication Number:
  US 20150283312A1
• Time in Patent Office: 904 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 60/237 the blood flow through the rotating member having mainly axial components, e.g. axial flow 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

Abstract

Blood pump systems including a continuous flow blood pump and methods for controlling a continuous flow blood pump operate the blood pump to simulate target pressure-flow characteristics that are different from native pressure-flow characteristics of the blood pump. A method for controlling a continuous flow blood pump driven by a motor includes operating the motor at a first rotational rate. A first flow rate of the continuous flow blood pump driven at the first rotational rate is measured and/or estimated. The first flow rate is used to determine a second rotational rate based on target pump characteristic data corresponding to target pressure-flow characteristics for the continuous flow blood pump different from pressure-flow characteristics of the continuous flow blood pump when driven by the motor at a constant rotational speed. The second rotational rate is different from the first rotational rate. The motor is then operated at the second rotational rate.

Claims

1. A blood pump system for providing ventricular assistance to a patient, the blood pump system comprising:

a continuous flow blood pump;

a motor drivingly coupled with the continuous flow blood pump; and

a control unit operatively coupled with the motor, the control unit including a processor and memory storing (a) target pump characteristic data defining a target pressure-flow curve for the continuous flow blood pump, the target pressure-flow curve being different from a pressure-flow characteristics curve of the continuous flow blood pump when driven by the motor at a constant rotational rate, and (b) instructions that when executed by the processor cause the processor to;

operate the motor at a first rotational rate;

determine a first flow rate of the continuous flow blood pump driven by the motor at the first rotational rate;

determine a second rotational rate for the motor as a function of the first rotational rate and the first flow rate via accessing the target pump characteristic data, the second rotational rate being different from the first rotational rate and selected to cause the continuous flow blood pump to generate a resulting pressure differential and a resulting flow rate in conformance with the target pressure-flow curve; and

operate the motor at the second rotational rate.

2. The blood pump system of claim 1, wherein the instructions, when executed by the processor, further cause the processor to estimate the first flow rate based on the first rotational rate and a current or power consumption of the motor.

3. The blood pump system of claim 1, wherein the instructions, when executed by the processor, cause the processor to estimate a pressure differential across the blood pump based on the first rotational rate and a current or power consumption of the motor and use the estimated pressure differential in the determination of the second rotational rate.

4. The blood pump system of claim 1, wherein the target pump characteristic data includes a specified power-speed relationship.

5. The blood pump system of claim 4, wherein the target pump characteristic data includes a plurality of different power-speed relationships, each of the power-speed relationships corresponding to a respective operational level for the blood pump.

6. The blood pump system of claim 1, wherein the target pump characteristic data defines a target pressure differential across the pump as a function of flow rate through the blood pump.

7. The blood pump system of claim 1, wherein the target pump characteristic data includes data corresponding to a plurality of different operational levels of the blood pump, each of the different operational levels of the blood pump producing a different differential pressure across the blood pump for a reference flow rate through the blood pump.

8. The blood pump system of claim 1, wherein the instructions, when executed by the processor, cause the processor to:

determine a second flow rate of the continuous flow blood pump driven by the motor at the second rotational rate;

determine a third rotational rate for the motor as a function of the second rotational rate and the second flow rate via accessing the target pump characteristic data, the third rotational rate being different from each of the first and second rotational rates and selected to cause the continuous flow blood pump to generate a second resulting pressure differential and a second resulting flow rate in conformance with the target pressure-flow curve; and

operate the motor at the third rotational rate.

9. The blood pump system of claim 1, wherein the continuous flow blood pump comprises an axial flow pump, a centrifugal pump, or a mixed flow pump.

10. A method for controlling a continuous flow blood pump driven by a motor, the method comprising:

operating the motor at a first rotational rate;

measuring and/or estimating a first flow rate of the continuous flow blood pump driven by the motor at the first rotational rate;

determining a second rotational rate for the motor as a function of the first rotational rate and the first flow rate via accessing target pump characteristic data stored in a memory device, the target pump characteristic data defining a target pressure-flow curve for the continuous flow blood pump, the target pressure-flow curve being different from a pressure-flow curve of the continuous flow blood pump when driven by the motor at a constant rotational rate, the second rotational rate being different from the first rotational rate and selected to cause the continuous flow blood pump to generate a resulting pressure differential and a resulting flow rate in conformance with the target pressure-flow curve; and

operating the motor at the second rotational rate.

11. The method of claim 10, wherein the first flow rate is estimated based on the first rotational rate and a current or power consumption of the motor.

12. The method of claim 10, wherein the first flow rate is measured.

13. The method of claim 10, wherein determining the second rotational rate includes estimating a pressure differential across the blood pump based on the first rotational rate and a current or power consumption of the motor.

14. The method of claim 10, wherein determining the second rotational rate includes measuring a pressure difference across the blood pump.

15. The method of claim 10, wherein the target pump characteristic data includes a specified power-speed relationship.

16. The method of claim 15, wherein the target pump characteristic data includes a plurality of different power-speed relationships, each of the power-speed relationships corresponding to a respective operational level for the blood pump.

17. The method of claim 10, wherein the target pump characteristic data defines a target pressure differential across the pump as a function of flow rate through the blood pump.

18. The method of claim 10, wherein the target pump characteristic data includes data corresponding to a plurality of different operational levels of the blood pump, each of the different operational levels of the blood pump producing a different differential pressure across the blood pump for a reference flow rate through the blood pump.

19. The method of claim 10, comprising:

measuring and/or estimating a second flow rate of the continuous flow blood pump driven by the motor at the second rotational rate;

determining a third rotational rate for the motor as a function of the second rotational rate and the second flow rate via accessing the target pump characteristic data stored in the memory device, the third rotational rate being different from each of the first and second rotational rates and selected to cause the continuous flow blood pump to generate a second resulting pressure differential and a second resulting flow rate in conformance with the target pressure-flow curve; and

operating the motor at the third rotational rate.

20. The method of claim 10, wherein the continuous flow blood pump comprises an axial flow pump, a centrifugal pump, or a mixed flow pump.