AUTOMATED INTEGRITY TESTS

• US 20090259216A1
• Filed: 04/10/2008
• Published: 10/15/2009
• Est. Priority Date: 04/10/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Goetz, Steven M., Drew, Touby A.
• Granted Patent: US 8,287,520 B2
• Time in Patent Office: Days
• US Class Current: 604/891.100
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 5/1117 Fall detection
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/36535 controlled by body position or posture
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371

Abstract

Techniques for testing integrity of various elements of implantable medical device systems are described. Some embodiments automatically test the integrity of one or more system elements in response to detecting an event. Examples of events in response to which an integrity test may be performed include the patient being within a target activity state, a symptomatic event experienced by a patient, an external impact on the patient that exceeds a damage threshold, or an indication that the patient is receiving inappropriate therapy. Some embodiments automatically test integrity in response to failure to autonomously detect an event, which may be indicated by input from a patient. An implantable lead carrying electrodes or a therapeutic substance delivery element, such as a catheter, are examples of system elements for which integrity may be tested in some embodiments.

Claims

1. A method comprising:

monitoring a signal from a sensor that detects a physiological parameter of a patient;

determining whether an event is detected based on the signal; and

automatically testing integrity of a therapeutic substance delivery element based on the determination of whether the event is detected,

wherein the therapeutic substance delivery element delivers a therapeutic substance from an implantable medical device to a target therapy delivery site in the patient.

2. The method of claim 1, wherein testing integrity comprises at least one of measuring a pressure within the therapeutic substance delivery element, or measuring flow of the therapeutic substance within the therapeutic substance delivery element.

3. The method of claim 1, wherein determining whether an event is detected comprises at least one of determining whether the patient experienced a symptomatic event, or determining whether the patient is within a target activity state.

4. The method of claim 1, wherein the event comprises at least one of an abnormal signal from the sensor, or an external force with a magnitude that exceeds a threshold.

5. The method of claim 1, further comprising:

detecting an occlusion in the therapeutic substance delivery element based on the integrity test; and

altering a pumping characteristic of a pump within the medical device that delivers the therapeutic agent to the therapeutic substance delivery element to clear the occlusion.

6. The method of claim 1, further comprising providing an alert to the patient based on the integrity test.

7. The method of claim 1, wherein determining whether the event is detected comprises detecting the event, and wherein testing integrity comprises testing integrity in response to the detection.

8. The method of claim 1, wherein determining whether the event has been detected comprises determining that the event has not been detected for a threshold period of time, and testing integrity comprises testing integrity in response to the determination that the event has not been detected for the threshold period of time.

9. The method of claim 1, wherein determining whether the event has been detected comprises:

receiving an indication from the patient that the event occurred; and

determining that the event was not detected based on the signal from the sensor, and

wherein testing integrity comprises testing integrity in response to the determination that the event was not detected based on the signal from the sensor.

10. The method of claim 9, further comprising testing the integrity of the sensor in response to the determination that the event was not detected based on the signal from the sensor.

11. The method of claim 1, wherein determining whether the event is detected comprises detecting the event, wherein testing integrity comprises testing integrity every N^th time the event is detected, and wherein N is an integer greater than 1.

12. The method of claim 1, wherein the therapeutic substance delivery element comprises at least one of a pump within the implantable medical device or an implantable catheter coupled to the pump.

13. The method of claim 1, further comprising:

detecting an intermittent occlusion in the therapeutic substance delivery clement based on the integrity test;

monitoring a duration of the occlusion; and

adjusting delivery of the therapeutic substance to make up for therapy missed throughout the duration of the occlusion.

14. An implantable medical device comprising:

an integrity measurement module configured to test integrity of a therapeutic substance delivery element that delivers a therapeutic substance from the implantable medical device to a target therapy delivery site in a patient; and

a processor that monitors a signal from a sensor that detects a physiological parameter of the patient, determines whether an event is detected based on the signal, and automatically controls the integrity measurement module to test integrity of the therapeutic substance delivery element based on the determination.

15. The implantable medical device of claim 14, wherein the processor controls the integrity measurement module to at least one of measure a pressure within the therapeutic substance delivery element, or measure flow of the therapeutic substance within the therapeutic substance delivery element to test the integrity of the therapeutic substance delivery element.

16. The implantable medical device of claim 14, wherein the event comprises a symptomatic event experienced by the patient.

17. The implantable medical device of claim 14, wherein the event comprises the patient being within a target activity state.

18. The implantable medical device of claim 14, wherein the event comprises at least one of an abnormal signal from the sensor, or an external force with a magnitude that exceeds a threshold.

19. The implantable medical device of claim 14, further comprising a pump that delivers the therapeutic agent to the therapeutic substance delivery element, wherein the processor detects an occlusion in the therapeutic substance delivery element based on the integrity test, and alters a pumping characteristic of the pump to clear the occlusion.

20. The implantable medical device of claim 14, wherein the processor detects the event based on the signals, and controls the integrity measurement module to test integrity of the therapeutic substance delivery element in response to the detection.

21. The implantable medical device of claim 14, wherein the processor determines that the event has not been detected for a threshold period of time, and controls the integrity measurement module to test integrity of the therapeutic substance delivery element in response to the determination that the event has not been detected for the threshold period of time.

22. The implantable medical device of claim 14, wherein the processor receives an indication from the patient that the event occurred, determines that the event was not detected based on the signal from the sensor, and controls the integrity measurement module to test integrity of the therapeutic substance delivery element in response to the determination that the event was not detected based on the signal from the sensor.

23. The implantable medical device of claim 22, wherein the processor controls the integrity measurement module to test integrity of the sensor in response to the determination that the event was not detected based on the signal from the sensor.

24. The implantable medical device of claim 14, wherein the processor detects an intermittent occlusion in the therapeutic substance delivery element based on the integrity test, monitors a duration of the occlusion, and adjusts delivery of the therapeutic substance to make up for therapy missed throughout the duration of the occlusion.

25. A method comprising:

monitoring a first signal from a first sensor of an implantable medical device system, wherein the first sensor detects a first physiological parameter of a patient;

determining that the patient is not receiving appropriate therapy based on the first signal; and

automatically testing integrity of at least one other element of the implantable medical device system based on the determination,

wherein the at least one other element comprises at least one of a therapy delivery element, a second sensor that detects a second physiological parameter of the patient, a software element, a firmware element, or a hardware element.

26. The method of claim 25, wherein determining that the patient is not receiving appropriate therapy based on the first signal comprises detecting at least one of unexpected energy content in a particular frequency band, or a value out of an expected physiological range.

27. The method of claim 25, wherein determining that the patient is not receiving appropriate therapy based on the first signal comprises determining that the first sensor is functioning properly.

28. The method of claim 25, further comprising providing an alert to the patient based on the integrity test.

29. The method of claim 25, wherein the therapy delivery element comprises at least one of a lead carrying at least one electrode that delivers electrical stimulation to the patient, or a therapeutic substance delivery element that delivers a therapeutic substance to a target therapy delivery site in the patient.

30. The method of claim 25, wherein the each of the first and second sensors comprises at least one of an electrode, an accelerometer, a sensor that detects at least one of activity or posture, an electroencephalogram sensor, an electromyogram sensor, an electrocardiogram sensor, a chemical sensor, an optical sensor, a pressure sensor, or a temperature sensor.

31. An implantable medical device comprising:

an integrity measurement module; and

a processor that monitors a signal from a first sensor that detects a first physiological parameter of a patient, determines that a patient is not receiving adequate therapy based on the first signal, and automatically controls the integrity measurement module to test integrity of at least one other element of an implantable medical device system that includes the implantable medical device based on the determination,

wherein the at least one other element comprises at least one of a therapy delivery element, a second sensor that detects a second physiological parameter of the patient, a software element, a firmware element, or a hardware element.

32. The implantable medical device of claim 31, wherein the processor detects at least one of unexpected energy content in a particular frequency band or a value out of an expected physiological range, and determines that the patient is not receiving appropriate therapy based on the detection.

33. The implantable medical device of claim 31, wherein the processor determines that the first sensor is functioning properly, and determines that the patient is not receiving appropriate therapy based on the determination that the first sensor is functioning properly.

34. The implantable medical device of claim 31, wherein the processor provides an alert to the patient based on the integrity test.

35. A method comprising:

monitoring a signal from a sensor of an implantable medical device system that detects at least one of activity, posture, or pressure;

detecting an external force with a magnitude that exceeds a threshold based on the signal; and

automatically testing integrity of at least one element of the implantable medical device system in response to the detection,

wherein the at least one element comprises at least one of a therapy delivery element, the sensor, another sensor that detects another physiological parameter of the patient, a software element, a firmware element, or a hardware element.

36. The method of claim 35, further comprising providing an alert to the patient based on the integrity test.

37. The method of claim 35, wherein the sensor comprises an accelerometer.

38. The method of claim 35, wherein the therapy delivery element comprises at least one of a lead carrying at least one electrode that delivers electrical stimulation to the patient, or a therapeutic substance delivery element that delivers a therapeutic substance to a target therapy delivery site in the patient.

39. The method of claim 35, wherein the at least one element comprises at least one of an electrode, an accelerometer, a sensor that detects at least one of activity or posture, an electroencephalogram sensor, an electromyogram sensor, an electrocardiogram sensor, a chemical sensor, an optical sensor, a pressure sensor, or a temperature sensor.

40. The method of claim 35, wherein the threshold comprises a system damage threshold.

41. The method of claim 35, wherein the force comprises at least one of an acceleration or an external impact.

42. An implantable medical device comprising:

an integrity measurement module; and

a processor that monitors a signal from a sensor that detects at least one of activity, posture, or pressure, detects an external force with a magnitude that exceeds a threshold based on the signal, and automatically tests integrity of at least one element of the implantable medical device system in response to the detection,

wherein the at least one element comprises at least one of a therapy delivery element, the sensor, another sensor that detects another physiological parameter of the patient, a software element, a firmware element, or a hardware element.

43. The medical device of claim 42, wherein the processor provides an alert to the patient based on the integrity test.

44. The medical device of claim 42, wherein the sensor comprises an accelerometer.

45. The medical device of claim 42, wherein the threshold comprises a system damage threshold.

46. The medical device of claim 42, wherein the force comprises at least one of an acceleration or an external impact.