POWER SUPPLY MONITORING FOR AN IMPLANTABLE DEVICE

• US 20100274302A1
• Filed: 05/21/2010
• Published: 10/28/2010
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Cyberonics, Inc
• Original Assignee: Cyberonics, Inc
• Inventors: Armstrong, Randolph K., Nguyen, Huan D., Guzman, Albert W.
• Granted Patent: US 8,086,310 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

A method and an apparatus for projecting an end of service (EOS) and/or an elective replacement indication (ERI) of a component in an implantable device and for determining an impedance experienced by a lead associated with the implantable device. An active charge depletion of an implantable device is determined. An inactive charge depletion of the implantable device is determined. A time period until an end of service (EOS) and/or elective replacement indication (ERI) of a power supply associated with the IMD based upon the active charge depletion, the inactive charge depletion, and the initial and final (EOS) battery charges, is determined. Furthermore, to determine the impedance described above, a substantially constant current signal is provided through a first terminal and a second terminal of the lead. A voltage across the first and second terminals is measured. An impedance across the first and second terminals is determined based upon the constant current signal and the measured voltage.

Claims

1. A method for determining a time period until an end of service of an energy storage device in an implantable medical device, said energy storage device comprising a total available electrical charge that may be obtained from said energy storage device, said method comprising:

determining a first current usage rate for a first future current usage period of an implantable medical device;

determining a second current usage rate for a second future current usage period of an implantable medical device;

determining a future combined current usage rate based upon said first future current usage rate and said second current usage rate; and

determining a total charge depleted by said implantable medical device by

determining a charge depleted during at least a first prior current usage period, and

determining a charge depleted during at least a second prior current usage period; and

determining a time period until an end of service of the energy storage device based upon said total available electrical charge, said total charge depleted, and said future combined current usage rate.

2. The method of claim 1, wherein said energy storage devices comprises a battery.

3. The method of claim 1 wherein said first prior current usage period comprises a stimulation period.

4. The method of claim 1 wherein said second prior current usage period comprises an inactive period.

5. The method of claim 1, further comprising the step of determining a third current usage rate for a third future current usage period of an implantable medical device, and wherein said step of determining a future combined current usage rate comprises determining a future combined current usage rate based upon said first future current usage rate, said second current usage rate, and said third current usage rate.

6. The method of claim 5 wherein said first future current usage period comprises an inactive period, said second future current usage period comprises a stimulation period, and said third future current usage period comprises a stimulation period, and wherein said second future current usage rate is different from said third current usage rate.

7. A method for determining the remaining useful life of an energy storage device in an implantable medical device, said energy storage device having a total available electrical charge that may be obtained from said energy storage device, said method comprising:

determining an active charge depletion of the implantable medical device;

determining an inactive charge depletion of said implantable medical device; and

determining a time period until an end of service of the energy storage device based upon said active charge depletion, said inactive charge depletion, and said total available charge.

8. The method of claim 7, wherein determining an active charge depletion of an implantable medical device further comprises determining a charge depleted during a previous stimulation performed by said implantable device.

9. The method of claim 8, wherein determining an active charge depletion of an implantable medical device further comprises determining an active current usage rate for a future stimulation to be performed by said implantable device.

10. The method of claim 9, wherein determining an active current usage rate for a future stimulation to be performed by said implantable medical device further comprises correlating a first predetermined current usage rate with a first stimulation performed by said implantable device.

11. The method of claim 10, wherein correlating said first predetermined current usage rate with said first stimulation performed by said implantable device further comprises calibrating said first predetermined current usage rate based upon at least one stimulation parameter.

12. The method of claim 10, wherein correlating said first predetermined current usage rate with said first stimulation performed by said implantable device further comprises calibrating said first predetermined current usage rate based upon a lead impedance.

13. The method of claim 10, wherein determining an active current usage rate for a future stimulation to be performed by said implantable medical device further comprises correlating a second predetermined current usage rate with a second stimulation performed by said implantable device.

14. The method of claim 13, wherein correlating said second predetermined current usage rate with said second stimulation performed by said implantable device further comprises calibrating said second predetermined current usage rate based upon at least one stimulation parameter.

15. The method of claim 7, wherein said energy storage device comprises a battery.

16. The method of claim 7, wherein determining an inactive charge depletion of an implantable medical device further comprises determining a charge depleted during a previous idle period of said implantable medical device.

17. The method of claim 7, wherein determining an inactive charge depletion of said implantable medical device further comprises determining an idle current usage rate for a future idle period of said implantable medical device.

18. The method of claim 17, further comprising calibrating said idle current usage rate for a previous idle time period.

19. The method of claim 7, further comprising generating an end of service signal based upon a determination that said time period until said end of service equals zero.

20. The method of claim 7, further comprising generating an end of service signal based upon a determination that said end of service has already occurred.

21. The method of claim 20, further comprising generating an elective replacement indicator signal based upon a determination that said time period until said end of service is less than or equal to a predetermined period.

22. The method of claim 21, wherein said predetermined period is six months.

23-27. -27. (canceled)

28. A method for determining the remaining useful life of a battery in an implantable medical device, said battery having a first charge and a second charge less than said first charge comprising:

determining a total available charge for said battery comprising the difference between said first charge and said second charge;

determining a charge depletion of the implantable medical device; and

determining a time period until an end of service of a power supply associated with said implantable medical device based upon said charge depletion and said total available charge.

29-66. -66. (canceled)