FILTER MECHANISM FOR REMOVING ECG ARTIFACT FROM MECHANICAL CHEST COMPRESSIONS

• US 20130296727A1
• Filed: 11/14/2012
• Published: 11/07/2013
• Est. Priority Date: 05/03/2012
• Status: Active Grant

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Sullivan, Joseph L., Walker, Robert G., Marx, Robert
• Granted Patent: US 9,084,545 B2
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61H 2201/5007 computer controlled
• CPC Class Codes: A61H 2201/5043 Displays
• CPC Class Codes: A61H 2201/5097 wireless
• CPC Class Codes: A61H 2230/045 used as a control parameter for the apparatus
• CPC Class Codes: A61H 2230/206 used as a control parameter for the apparatus
• CPC Class Codes: A61H 2230/208 used as a control parameter for the apparatus
• CPC Class Codes: A61H 2230/305 used as a control parameter for the apparatus A61H2230/045 takes precedence
• CPC Class Codes: A61H 31/005 with feedback for the user
• CPC Class Codes: A61H 31/006 Power driven
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3993 User interfaces for automatic external defibrillators

Abstract

An external medical device can include a housing and a processor within the housing. The processor can be configured to receive an input signal for a patient receiving chest compressions from a mechanical chest compression device. The processor can also be configured to select at least one filter mechanism, the mechanical chest compression device having a chest compression frequency f. The processor can be further configured to apply the at least one filter mechanism to the signal to at least substantially remove chest compression artifacts from the signal, wherein the chest compression artifacts correspond to the chest compressions being delivered to the patient by the mechanical chest compression device, and wherein the at least one filter mechanism substantially rejects content in the frequency f plus content in at least one more frequency that is a higher harmonic to the frequency f.

Claims

1. An external medical device, comprising:

a housing; and

a processor within the housing configured to;

receive an input signal for a patient receiving chest compressions from a mechanical chest compression device;

select at least one filter mechanism, the mechanical chest compression device having a chest compression frequency f;

apply the at least one filter mechanism to the input signal to at least substantially remove chest compression artifacts from the input signal, wherein the chest compression artifacts correspond to the chest compressions being delivered to the patient by the mechanical chest compression device, and wherein the at least one filter mechanism substantially rejects content in the frequency f plus content in at least one more frequency that is a higher harmonic to the frequency f but substantially passes frequencies between the frequency f and the higher harmonic.

2. The device of claim 1, further comprising:

a display in connection with the housing.

3. The device of claim 2, in which

the processor is further configured to cause the display to visually present the filtered ECG data to a user.

4. The device of claim 1, in which

The filter mechanism substantially rejects content in the frequency f plus content in at least two more frequencies that are additional higher harmonics of the frequency f.

5. The device in claim 1, in which

the input signal is an ECG signal.

6. The device in claim 1, in which

the input signal is an impedance signal.

7. The device of claim 1, in which

the selecting is performed responsive to an identification of the mechanical chest compression device being used to deliver the chest compressions to the patient.

8. The device of claim 1, further comprising:

an energy storage module within the housing for storing an electrical charge, and

a defibrillation port for guiding via electrodes the stored electrical charge to the patient.

9. The device of claim 1, in which

the mechanical chest compression device provides an indication of the frequency f to the processor.

10. The device of claim 1, in which

the at least one filter mechanism comprises a comb filter, a plurality of notch filters, or both.

11. The device of claim 10, in which

the at least one filter mechanism has a Q value of no less than 4.

12. The device of claim 10, in which

the plurality of notch filters has a 3 dB notch width of no more than approximately 0.5 Hz.

13. The device of claim 1, in which

the at least one filter mechanism includes a non-adaptive filter.

14. The device of claim 1, in which

the processor is further configured to detect the chest compressions being delivered to the patient.

15. The device of claim 1, in which

the processor is preconfigured to apply the at least one filter mechanism.

16. The device of claim 1, in which

the processor is configured to apply the at least one filter mechanism to the ECG data responsive to input received from a user.

17. The device of claim 1, in which

the processor is configured to select the at least one filter mechanism responsive to input received from a user.

18. The device of claim 1, in which

the processor is configured to select the at least one filter mechanism responsive to input received from the mechanical chest compression device delivering the chest compressions to the patient.

19. The device of claim 1, in which

the processor is further configured to suppress application of the at least one filter mechanism to the ECG data responsive to a determination that the mechanical chest compression device is no longer delivering chest compressions to the patient.

20. The device of claim 1, in which

the processor is further configured to monitor an impedance signal corresponding to the patient.

21. The device of claim 20, in which

the processor is further configured to detect return of spontaneous circulation (ROSC) by applying the at least one filter to the impedance signal.

22. A method in an external medical device, the method comprising:

receiving an input signal for a patient receiving chest compressions from a mechanical chest compression device, the mechanical chest compression device having a chest compression frequency f;

selecting at least one filter mechanism; and

applying the at least one filter mechanism to the received signal to at least substantially remove chest compression artifacts therefrom, wherein the chest compression artifacts correspond to the chest compressions being delivered to the patient by the mechanical chest compression device, and wherein the applying includes;

substantially rejecting content in the frequency f by the at least one filter mechanism, and

substantially rejecting content in at least one more frequency that is a higher harmonic to the frequency f by the at least one filter mechanism.

23. The method of claim 22, in which

the receiving, selecting, and applying are each part of a post-event review.

24. The method of claim 22, in which

the input signal is an ECG signal.

25. The method of claim 22, in which

the input signal is an impedance signal.

26. The method of claim 22, further comprising:

visually presenting the filtered signal to a user.

27. The method of claim 22, in which

the selecting is based on a chest compression rate, a sample rate of the ECG data, an identification of the mechanical chest compression device being used to deliver the chest compressions to the patient, or a combination thereof.

28. The method of claim 22, further comprising:

storing an electrical charge, and

guiding via electrodes the stored electrical charge to the patient.

29. The method of claim 22, further comprising:

detecting the chest compressions being delivered to the patient.

30. The method of claim 22, further comprising:

determining whether the mechanical chest compression device is still delivering chest compressions to the patient.

31. The method of claim 22, further comprising:

suppressing the applying responsive to a determination that the mechanical chest compression device is no longer delivering chest compressions to the patient.

32. The method of claim 22, further comprising:

monitor an impedance signal corresponding to the patient.

33. The method of claim 32, further comprising:

applying a signal-averaging filter to the impedance signal to detect a return of spontaneous circulation (ROSC).

34. The method of claim 22, in which

the at least one filter mechanism comprises a comb filter.

35. The method of claim 34, in which

the comb filter is non-adaptive.

36. The method of claim 22, in which

the at least one filter mechanism comprises a plurality of notch filters.

37. The method of claim 22, in which

each of the notch filters is non-adaptive.

38. A method in an external medical device, the method comprising:

receiving a signal containing ECG data for a patient receiving chest compressions from a mechanical chest compression device, the mechanical chest compression device having a chest compression frequency f;

selecting at least one filter mechanism;

applying the at least one filter mechanism to the received signal to at least substantially remove chest compression artifacts from the ECG data, wherein the chest compression artifacts correspond to the chest compressions being delivered to the patient by the mechanical chest compression device, and wherein the applying comprises;

the at least one filter mechanism substantially rejecting content in the frequency f; and

the at least one filter mechanism substantially rejecting content in at least one more frequency that is a higher harmonic to the frequency f; and

determining a pattern of the chest compression artifacts corresponding to the chest compressions being delivered to the patient.

39. The method of claim 38, further comprising:

determining whether the pattern matches an existing chest compression signature.

40. A system for treating a patient experiencing cardiac arrest, the system comprising:

a mechanical chest compression device configured to deliver chest compressions to the patient at a frequency f, the mechanical chest compression device having precise frequency control; and

a patient monitor configured to receive at least one input signal from the patient and remove signal content at the frequency f from the at least one input signal.

41. The system of claim 40, in which

the mechanical chest compression device produces CPR artifacts having spectral peaks within the at least one input signal.

42. The system of claim 41, in which

the spectral peaks each have a narrow bandwidth.

43. The system of claim 41, in which

the at least one input signal is an ECG signal.

44. The system of claim 41, in which

the at least one input signal is an impedance signal.