Event Registration for Automatic Threshold Setting

• US 20080161701A1
• Filed: 12/28/2006
• Published: 07/03/2008
• Est. Priority Date: 12/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Kessels, Roger, Bullens, Roland W.M.
• Granted Patent: US 8,052,610 B2
• Time in Patent Office: Days
• US Class Current: 600/481
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37258 Alerting the patient
• CPC Class Codes: G08B 21/0453 worn on the body to detect health condition by physiological monitoring, e.g. electrocardiogram, temperature, breathing detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

An implantable medical device includes a sensor for sensing a first signal in a patient, detection circuitry for receiving the first signal, determining a parameter therefrom, and detecting a first event in response to the parameter. The device further includes control circuitry configured to receive a second signal corresponding to a second event and to determine a threshold from the stored parameter in response to receiving the second event signal. The detection circuitry detects the first event in response to the parameter crossing the determined threshold.

Claims

1. An implantable medical device, comprising:

a sensor for sensing a first signal in a patient,

detection circuitry for receiving the first signal, determining a parameter corresponding to the first signal, and detecting a first event in response to the parameter;

memory for storing the parameter; and

control circuitry configured to receive a second signal corresponding to a second event and further configured to determine a threshold from the stored parameter in response to receiving the second event signal;

wherein the detection circuitry detects the first event in response to the parameter crossing the determined threshold.

2. A device according to claim 1 further comprising alarm circuitry for generating an alarm signal in response to the detected first event.

3. A device according to claim 1 wherein determining the threshold comprises determining a value of the stored parameter at a time prior to the second event signal.

4. A device according to claim 1 further comprising telemetry circuitry coupled to the control circuitry and wherein the second signal being an externally generated signal received by the telemetry circuitry.

5. A device according to claim 1 wherein the second event corresponds to a worsening of the parameter subsequent to the first event.

6. A device according to claim 1 wherein the second event corresponds to a hospitalization.

7. A device according to claim 1 wherein the sensor being an impedance sensor.

8. A device according to claim 7 wherein the impedance sensor being configured for sensing thoracic impedance.

9. A device according to claim 1 wherein the sensor being an impedance sensor configured for sensing thoracic impedance, the first event corresponding to a thoracic fluid level, the second event being a hospitalization, and wherein determining the threshold comprises determining the parameter value at a predetermined time prior to the hospitalization.

10. A method for use in an implantable medical device, comprising:

sensing a first signal in a patient,

determining a parameter corresponding to the first signal;

storing the parameter;

detecting a first event in response to the parameter;

receiving a second signal corresponding to a second event; and

determining a threshold corresponding to the stored parameter in response to receiving the second event signal;

wherein the first event being detected in response to the parameter crossing the determined threshold.

11. A method according to claim 10 further comprising generating an alarm signal in response to the detected first event.

12. A method according to claim 10 wherein determining the threshold comprises determining a value of the stored parameter at a time prior to the second event signal.

13. A method according to claim 10 wherein the second signal being a telemetry signal received by the implantable medical device and transmitted from an external device.

14. A method according to claim 10 wherein the second event corresponds to a worsening of the parameter subsequent to the first event.

15. A method according to claim 10 wherein the second event corresponds to a hospitalization.

16. A method according to claim 10 wherein the first signal being an impedance signal.

17. A method according to claim 16 wherein the impedance signal corresponds to thoracic impedance.

18. A method according to claim 10 wherein the first signal being a thoracic impedance signal, the first event corresponding to a thoracic fluid level, the second event being a hospitalization, and determining the threshold comprises determining the parameter value at a predetermined time prior to the hospitalization.

19. A computer-readable medium for storing a set of instructions which when implemented in an implantable medical device system including a microprocessor cause the system to:

sense a first signal in a patient,

determine a parameter corresponding to the first signal,

store the parameter;

detect a first event in response to the parameter;

receive a second signal corresponding to a second event; and

determine a threshold from the stored parameter in response to receiving the second event signal;

wherein the first event being detected in response to the parameter crossing the determined threshold.

20. A computer-readable medium according to claim 19 further comprising instructions which cause the system to generate an alarm signal in response to the detected first event.

21. A computer-readable medium according to claim 19 wherein determining the threshold comprises determining a value of the stored parameter at a time prior to the second event signal.

22. A computer-readable medium according to claim 19 wherein the second signal being a telemetry signal received by the implantable medical device and transmitted from an external device.

23. A computer-readable medium according to claim 19 wherein the second event corresponds to a worsening of the parameter subsequent to the first event.

24. A computer-readable medium according to claim 19 wherein the second event corresponds to a hospitalization.

25. A computer-readable medium according to claim 19 wherein the first signal being an impedance signal.

26. A computer-readable medium according to claim 25 wherein the impedance signal corresponds to thoracic impedance.

27. A computer-readable medium according to claim 19 wherein the first signal being a thoracic impedance signal, the first event corresponding to a thoracic fluid level, the second event being a hospitalization, and wherein determining the threshold comprises determining the parameter value at a predetermined time prior to the hospitalization.

28. An implantable medical device system, comprising:

an implanted sensor for sensing a first signal in a patient,

detection circuitry for receiving the first signal, determining a parameter corresponding to the first signal, and detecting a first event in response to the parameter;

memory for storing the parameter;

control circuitry configured to receive a second signal corresponding to a second event and further configured to determine a threshold from the stored parameter in response to receiving the second event signal;

an implantable telemetry circuit coupled to the control circuit; and

an external telemetry circuit in bidirectional communication with the implantable telemetry circuit, the external telemetry circuit adapted to transmit the second signal to the implantable telemetry circuit;

wherein the detection circuitry detects the first event in response to the parameter crossing the determined threshold.