FLUID DELIVERY SYSTEM AND METHOD FOR MONITORING FLUID DELIVERY SYSTEM

• US 20110313238A1
• Filed: 06/22/2011
• Published: 12/22/2011
• Est. Priority Date: 06/22/2010
• Status: Active Grant

• Current Assignee: TC1 LLC (Abbott Laboratories Incorporated)
• Original Assignee: Thoratec LLC
• Inventors: Reichenbach, Steven H., Law, Yu Fai, Hsu, George Chao-chih
• Granted Patent: US 8,905,910 B2
• Time in Patent Office: Days
• US Class Current: 600/16
• CPC Class Codes: A61M 2205/3365 Rotational speed
• 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 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/221 the blood flow through the rotating member having both radial and axial components, e.g. mixed flow pumps
• CPC Class Codes: A61M 60/232 Centrifugal pumps
• 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 60/258 Piston pumps
• CPC Class Codes: A61M 60/515 Regulation using real-time patient data
• CPC Class Codes: A61M 60/531 using blood pressure data, e.g. from blood pressure sensors
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed

Abstract

A fluid delivery system includes an electric motor, a pump driven by the electric motor, and a control system. The control system is programmed to supply a variable voltage to the electric motor, to sense a response of a current of the electric motor to the variable voltage, and to obtain frequency domain information about the response of the current of the electric motor.

Claims

1. A system configured to control, monitor, or evaluate a blood pump driven by a motor, the system comprising:

a device programmed to analyze a driving signal with a non-steady component to the motor or the blood pump and a corresponding response signal received from the motor or to analyze two different response signals received from the motor resulting from the driving signal with the non-steady component, and to determine from the analysis whether the blood pump is in operation under either a pump event or a physiological event.

2. The system of claim 1, wherein the analysis includes generating information including one or a combination of frequency domain information, time domain information, and amplitude information, and comparing the information with data representative of one or both of the pump event and the physiological event.

3. The system of claim 1, further comprising a memory device storing data representative of one or both of the pump event and the physiological event, the memory device in communication with the device programmed to analyze.

4. The system of claim 1, wherein the pump event is one or a combination of events selected from the group consisting of occlusion, additional friction within the blood pump, thrombosis within the blood pump, kink in a graft or artificial conduit attached to the blood pump, increased drag on a rotor of the blood pump, increased drag on an impeller of the blood pump, and increased drag on an internal bearing of the blood pump.

5. The system of claim 1, wherein the physiological event is a change in peripheral vascular resistance.

6. The system of claim 1, wherein the physiological event is a condition selected from the group consisting of hypertension, hypotension, hypervolemia, tachycardia, arrhythmia, and tamponade.

7. The system of claim 1, wherein the device is programmed to match, in accordance with the analysis, an operating condition of the blood pump to a specific pump event from a plurality of pump events including occlusion, additional friction within the blood pump, thrombosis within the blood pump, kink in a graft or artificial conduit attached to the blood pump, increased drag on a rotor of the blood pump, increased drag on an impeller of the blood pump, increased drag on an internal bearing of the blood pump, and combinations thereof.

8. The system of claim 7, wherein the analysis includes phase-and-power analysis, amplitude-and-power analysis, or a combination thereof.

9. The system of claim 7, wherein the device is programmed to distinguish, in accordance with the analysis, the specific pump event from any one or plurality of physiological events including hypertension, hypotension, hypervolemia, tachycardia, arrhythmia, and tamponade.

10. The system of claim 9, wherein the analysis includes any one or a combination of phase-and-power analysis, amplitude-and-power analysis, peak amplitude frequency analysis, frequency-domain analysis, time-domain analysis, and time-frequency-domain analysis.

11. The system of claim 1, wherein the driving signal is based on the heart of a patient.

12. The system of claim 1, wherein the device is configured to supply the driving signal to the motor.

13. The system of claim 1, wherein the analysis includes generating frequency domain information that includes one or more of a transfer function component of the driving signal to the response signal, and a transfer function component of a first signal of the two different response signals to a second signal of the two different response signals, wherein each of the transfer function components includes phase information or amplitude information.

14. The system of claim 1, wherein the analysis includes generating frequency domain information that includes a transfer function of a pair of signals, the pair of signals selected from the group consisting of motor voltage and motor current, motor voltage and rotor speed, motor voltage and motor power, speed command signal and motor current, speed command signal and rotor speed, speed command signal and motor power, motor current and rotor speed, and motor power and rotor speed.

15. The system of claim 14, wherein the transfer function component is amplitude information of a first signal of the pair of signals at a selected frequency divided by amplitude information of a second signal of the pair of signals at the selected frequency.

16. The system of claim 14, wherein the device is programmed to determine a degree of pump occlusion based at least on the transfer function.

17. The system of claim 1, wherein the analysis includes generating frequency domain information that includes a phase angle of the response signal at a selected frequency.

18. The system of claim 17, wherein the frequency domain information includes a phase difference, the phase difference being a phase angle of the driving signal at the selected frequency minus the phase angle of the response signal at the given frequency.

19. The system of claim 18, wherein the device is programmed to determine a degree of pump occlusion based at least on the phase difference.

21. A pump system functioning as a ventricular assist device, the pump system comprising:

a blood pump driven by a motor; and

the device according to claim 1.

20. The system of claim wherein the device is programmed to determine a degree of pump occlusion based at least on one or more of:

(a) a phase difference between the driving signal and the response signal at a selected frequency,

(b) a predetermined relationship between a degree of pump occlusion and a phase difference between the driving signal and the response signal,

(c) whether a phase difference between the driving signal and the response signal is negative or positive,

(d) a historic record of phase difference between the driving signal and the response signal, and

(e) a change in a phase difference between the driving signal and the response signal.

22. A method for controlling or monitoring a blood pump driven by a motor, the method comprising:

analyzing a driving signal with a non-steady component to the motor or the blood pump and a corresponding response signal received from the motor, or analyzing two different response signals received from the motor resulting from the driving signal with the non-steady component; and

determining from the analysis whether the blood pump is in operation under either a pump event or a physiological event.

23. The method of claim 22, wherein the analyzing step includes generating information including one or a combination of frequency domain information and time domain information, and comparing the information with data representative of one or both of the pump event and the physiological event.

24. The method of claim 22, wherein the pump event is a condition selected from the group consisting of occlusion, additional friction within the blood pump, thrombosis within the blood pump, kink in a graft or artificial conduit attached to the blood pump, increased drag on a rotor of the blood pump, increased drag on an impeller of the blood pump, increased drag on an internal bearing of the blood pump, and combinations thereof.

25. The method of claim 22, wherein the physiological event is a change in peripheral vascular resistance.

26. The method of claim 22, wherein the physiological event is a condition selected from the group consisting of hypertension, hypotension, hypervolemia, tachycardia, arrhythmia, and tamponade.

27. The method of claim 22, wherein the determining step includes matching an operating condition of the blood pump to a specific pump event from a plurality of pump events including occlusion, additional friction within the blood pump, thrombosis within the blood pump, kink in a graft or artificial conduit attached to the blood pump, increased drag on a rotor of the blood pump, increased drag on an impeller of the blood pump, increased drag on an internal bearing of the blood pump, and combinations thereof.

28. The method of claim 27, wherein the analysis step includes phase-and-power analysis, amplitude-and-power analysis, or a combination thereof.

29. The method of claim 27, wherein the determining step includes distinguishing the specific pump event from at least one physiological event including hypertension, hypotension, hypervolemia, tachycardia, arrhythmia, and tamponade.

30. The method of claim 29, wherein the analysis step includes any one or a combination of phase-and-power analysis, amplitude-and-power analysis, peak amplitude frequency analysis, frequency-domain analysis, time-domain analysis, and time-frequency-domain analysis.