Hazard mitigation in medical device

• US 20030140274A1
• Filed: 01/23/2002
• Published: 07/24/2003
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Medtronic Emergency Response Systems Inc (Stryker Corporation)
• Inventors: Kelly, Patrick F., Neumiller, James S., DeBardi, Gary A.
• Granted Patent: US 6,957,368 B2
• Time in Patent Office: Days
• US Class Current: 714/24
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

Delivery of energy by a defibrillator or other medical device is inhibited when the processor or software that controls a module of the medical device operates abnormally. A windowed watchdog timer (WWDT) incorporated into one module of the medical device is used to control the operation of other modules of the medical device via a software-based extension technique. As a result, the risk of harm to the patient is reduced compared to medical devices that incorporate over-limit type watchdog timers. In addition, costs associated with implementing WWDTs in multiple modules of the defibrillator are avoided, thereby lowering the overall cost of implementation.

Claims

1. A method comprising:

in a first processor of a medical device, generating a handshake signal;

providing the handshake signal to a second processor of the medical device; and

causing the second processor to reset the first processor when the handshake signal is not provided within a prescribed time interval.

2. The method of claim 1, further comprising resetting the first processor when the handshake signal is provided before a minimum time or after a maximum time.

3. The method of claim 1, further comprising disabling therapy output hardware when the handshake signal is not provided within the prescribed time interval.

4. The method of claim 1, further comprising detecting an abnormal power condition and disabling therapy output hardware in response to the abnormal power condition.

5. The method of claim 1, further comprising detecting a voltage of the medical device.

6. The method of claim 5, further comprising selectively disabling therapy output hardware as a function of the detected voltage.

7. The method of claim 1, wherein the medical device comprises at least one of a therapy control module, a system controller, a user interface module, and a patient parameters module.

8. The method of claim 7, wherein the user interface module is communicatively coupled to at least one of a keyboard, a display screen, and a strip chart recorder.

9. The method of claim 7, wherein the patient parameters module is configured to obtain at least one of ECG information, vital sign measurements, non-invasive blood pressure (NIBP) measurements, and SpO₂ information from a patient.

10. The method of claim 1, wherein the medical device is an automated external defibrillator.

11. A processor-readable medium containing processor-executable instructions for:

in a first processor of a medical device, generating a handshake signal;

providing the handshake signal to a second processor of the medical device; and

causing the second processor to reset the first processor when the handshake signal is not provided within a prescribed time interval.

12. The processor-readable medium of claim 11, further containing instructions for resetting the first processor when the handshake signal is provided before a minimum time or after a maximum time.

13. The processor-readable medium of claim 11, further containing instructions for disabling therapy output hardware when the handshake signal is not provided within the prescribed time interval.

14. The processor-readable medium of claim 11, further containing instructions for detecting an abnormal power condition and disabling therapy output hardware in response to the abnormal power condition.

15. The processor-readable medium of claim 11, further containing instructions for detecting a voltage of the medical device.

16. The processor-readable medium of claim 15, further containing instructions for selectively disabling therapy output hardware as a function of the detected voltage.

17. The processor-readable medium of claim 11, wherein the medical device comprises at least one of a therapy control module, a system controller, a user interface module, and a patient parameters module.

18. The processor-readable medium of claim 17, wherein the user interface module is communicatively coupled to at least one of a keyboard, a display screen, and a strip chart recorder.

19. The processor-readable medium of claim 17, wherein the patient parameters module is configured to obtain at least one of ECG information, vital sign measurements, non-invasive blood pressure (NIBP) measurements, and SpO₂ information from a patient.

20. The processor-readable medium of claim 11, wherein the medical device is an automated external defibrillator.

21. A medical device comprising:

a first functional module comprising a first embedded processor configured to generate a handshake signal; and

a second functional module comprising a second embedded processor configured to receive the handshake signal and to reset the first embedded processor when the handshake signal is not provided within a prescribed time interval.

22. The medical device of claim 21, wherein at least one of the first and second functional modules comprises a windowed watchdog timer.

23. The medical device of claim 21, wherein at least one of the first and second embedded processors is configured to reset when the handshake signal is provided before a minimum time or after a maximum time.

24. The medical device of claim 21, further comprising therapy output hardware, wherein at least one of the first and second embedded processors is configured to disable the therapy output hardware when the handshake signal is not provided within the prescribed time interval.

25. The medical device of claim 21, further comprising a voltage monitor configured to detect an abnormal power condition and to disable therapy output hardware in response to the abnormal power condition.

26. The medical device of claim 25, wherein the voltage monitor is further configured to detect a voltage of the medical device.

27. The medical device of claim 26, wherein the voltage monitor is further configured to selectively disable therapy output hardware as a function of the detected voltage.

28. The medical device of claim 21, wherein the medical device comprises at least one of a therapy control module, a system controller, a user interface module, and a patient parameters module.

29. The medical device of claim 28, wherein the user interface module is communicatively coupled to at least one of a keyboard, a display screen, and a strip chart recorder.

30. The medical device of claim 28, wherein the patient parameters module is configured to obtain at least one of ECG information, vital sign measurements, non-invasive blood pressure (NIBP) measurements, and SpO₂ information from a patient.

31. The medical device of claim 21, wherein the medical device is an automated external defibrillator.