Generating artificial pulse
In order to produce a pulsatile blood flow pattern that includes time periods of relatively high blood flow rates and time periods of relatively low blood flow rates, the operating speed of a blood pump can be selectively controlled to produce an operating speed pattern that includes time periods of relatively high rotation speeds and periods of relatively low rotation speeds. For example, the blood pump is rotated at a first speed for a first period of time. The speed of the blood pump is then decreased from the first speed to a second speed and is operated at the second speed for a second amount of time. The speed of the blood pump is then decreased to a third speed for a third amount of time. If desired, the operating speed pattern can be repeated to continue the pulsatile blood flow pattern.
1. A method of controlling an implantable blood pump, the method comprising:
operating the implantable blood pump in an artificial pulse mode for a first period of time;
transmitting a first signal to the implantable blood pump to transition the implantable blood pump from the artificial pulse mode to a perturbation mode;
operating the implantable blood pump in the perturbation mode for a second period of time;
transmitting a second signal to the implantable blood pump to transition the implantable blood pump from the perturbation mode to the artificial pulse mode; and
operating the implantable blood pump back in the artificial pulse mode.
2. The method of claim 1 , wherein operating the implantable blood pump in the perturbation mode comprises:
operating the implantable blood pump at a low speed for a first speed period;
increasing the speed of the implantable blood pump from the low speed to a high speed; and
operating the implantable blood pump at the high speed for a second speed period.
3. The method of claim 2 , further comprising operating the implantable blood pump at an intermediate speed for a third period of time.
4. The method of claim 3 , wherein the intermediate speed is between the low speed and high speed of the perturbation mode.
5. The method of claim 4 , wherein the intermediate speed at the third period of time is longer than the perturbation mode at the second period of time.
6. The method of claim 1 , wherein the operating the implantable blood pump in the perturbation mode comprises reducing a speed of the implantable blood pump to a low speed.
7. The method of claim 1 , wherein the perturbation mode stimulates a pulse pressure that occurs at a leading edge of systole of a physiologic pulse.
8. The method of claim 1 , wherein operating the implantable blood pump in the artificial pulse mode comprises:
(a) operating the implantable blood pump at a first speed for a first speed period;
(b) reducing the speed of the implantable blood pump from the first speed to a second speed;
(c) operating the implantable blood pump at the second speed for a second speed period;
(d) reducing the speed of the implantable blood pump from the second speed to a third speed;
(e) operating the implantable blood pump at the third speed for a third speed period; and
repeating steps (a)-(e).
9. The method of claim 8 , wherein a generated pulsatile blood flow includes a temporal rate of change of blood pressure that approximates a temporal rate of change of blood pressure of a physiologic pulse.
10. An implantable blood pump system, the system comprising:
an implantable blood pump configured to replace or partially assist a blood circulation function of a heart, the implantable blood pump operable in an artificial pulse mode and a perturbation mode; and
a controller coupled with the implantable blood pump and configured to transmit a first signal to the implantable blood pump to transition from operating in the artificial pulse mode to operating in the perturbation mode;
wherein the controller is further configured to transmit a second signal to the implantable blood pump to transition from operating in the perturbation mode to operating in the artificial pulse mode.
11. The implantable blood pump system of claim 10 , wherein operating the implantable blood pump in the perturbation mode comprises:
operating the implantable blood pump at a low speed for a first speed period;
increasing the speed of the implantable blood pump from the low speed to a high speed; and
operating the implantable blood pump at the high speed for a second speed period.
12. The implantable blood pump system of claim 11 , further comprising operating the implantable blood pump at an intermediate speed, wherein the intermediate speed is between the low speed and high speed of the perturbation mode.
13. The implantable blood pump system of claim 10 , wherein the operating the implantable blood pump in the perturbation mode comprises reducing a speed of the implantable blood pump to a low speed.
14. The implantable blood pump system of claim 10 , wherein operating the implantable blood pump in the artificial pulse mode comprises:
(a) operating the implantable blood pump at a first speed for a first speed period;
(b) reducing the speed of the implantable blood pump from the first speed to a second speed;
(c) operating the implantable blood pump at the second speed for a second speed period;
(d) reducing the speed of the implantable blood pump from the second speed to a third speed;
(e) operating the implantable blood pump at the third speed for a third speed period; and
repeating steps (a)-(e).
15. A blood pump controller comprising:
a waveform generator to generate a waveform for operating a blood pump; and
a drive waveform transmitter to supply the generated waveform to the blood pump;
wherein the generated waveform is configured to:
operate a blood pump in an artificial pulse mode for a first period of time; and
operate the blood pump in a perturbation mode for a second period of time.
16. The blood pump controller of claim 15 , wherein the generated waveform to operate the blood pump in the perturbation mode is in response to a first input received by the controller, wherein the drive waveform transmitter is configured to transmit a first signal to the implantable blood pump to transition operation in the artificial pulse mode to operation in the perturbation mode.
17. The blood pump controller of claim 16 , wherein the generated waveform is configured to operate the blood pump back in the artificial pulse mode in response to a second input received by the controller, wherein the drive waveform transmitter is configured to transmit a second signal to the implantable blood pump to transition operation in the perturbation mode to operation in the artificial pulse mode.
18. The blood pump controller of claim 15 , wherein the generated waveform is configured to change a speed of the blood pump from one or more of a step-wise change in speed and a curvilinear change in speed.
19. The blood pump controller of claim 15 , wherein the perturbation mode is configured to reduce a speed of the implantable blood pump to a low speed.
20. The blood pump controller of claim 15 , wherein the artificial pulse mode is configured to:
operate the implantable blood pump at a first speed for a first speed period;
reduce the speed of the implantable blood pump from the first speed to a second speed;
operate the implantable blood pump at the second speed for a second speed period;
reduce the speed of the implantable blood pump from the second speed to a third speed;
operate the implantable blood pump at the third speed for a third speed period; and
increase the speed of the blood pump from the third speed to the first speed.