ECG noise reduction system for removal of vehicle motion artifact

• US 9,642,575 B2
• Filed: 03/17/2014
• Issued: 05/09/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Freeman, Gary A., Herken, Ulrich R.
• Primary Examiner(s): MAHMOOD, NADIA AHMAD
• Application Number:
  US14/216,225
• Publication Number:
  US 20140288450A1
• Time in Patent Office: 1,149 Days
• Field of Search: 600509, 601 41
• CPC Class Codes: A61B 2560/0247 for compensation or correction of the measured physiological value
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6893 Cars
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence

Abstract

An ECG processing system which removes vehicle motion artifact from a measured ECG signal based on vehicle cabin motion and vehicle suspension motion.

Claims

1. An electrocardiogram (ECG) signal processing system for processing an ECG signal of a patient undergoing transport provided by a vehicle, said processing system comprising:

one or more vehicle motion sensors operably connected to the vehicle and operable to generate one or more signals corresponding to vehicle motion;

electrodes operable to measure the ECG signal of the patient;

an output device;

a processor communicatively coupled to the one or more vehicle motion sensors, the electrodes, and the output device, the processor configured to;

receive the one or more signals corresponding to the vehicle motion from the one or more vehicle motion sensors and the measured ECG signal from the electrodes,

process the one or more signals corresponding to the vehicle motion and the measured ECG signal to determine an estimated true ECG signal, and

output the estimated true ECG signal to the output device.

2. The ECG signal processing system of claim 1 further comprising a CPR motion sensor configured to provide a signal corresponding to motion of the chest of the patient during CPR chest compressions, wherein the processor is communicatively coupled to the CPR motion sensor and further configured to:

receive the signal corresponding to the motion of the chest of the patient during CPR chest compressions; and

process the signal corresponding to the motion of the chest of the patient during CPR chest compressions to determine the estimated true ECG signal.

5. The ECG signal processing system of claim 1 wherein the processor is further configured to:

estimate vehicle motion induced artifacts in the measured ECG signal based on the one or more signals corresponding to the vehicle motion; and

remove the estimated vehicle motion induced artifacts from the measured ECG signal to determine the estimated true ECG signal.

6. The ECG signal processing system of claim 5 wherein the processor further comprises a signal combiner configured to subtract the estimated vehicle motion induced artifacts from the measured ECG signal to determine the estimated true ECG signal.

7. The ECG signal processing system of claim 5 wherein the processor is further configured to estimate the vehicle motion induced artifacts in the measured ECG signal based on a linear predictive filter.

8. The ECG signal processing system of claim 7 wherein the processor is further configured to identify the linear predictive filter.

9. The ECG signal processing system of claim 5 wherein the processor is further configured to estimate the vehicle motion induced artifacts in the measured ECG signal based on a non-linear predictive filter.

10. The ECG signal processing system of claim 9 wherein the processor is further configured to identify the non-linear predictive filter.

11. The ECG signal processing system of claim 5 wherein the one or more vehicle motion sensors are operably connected to one or more components of the vehicle and wherein the one or more signals corresponding to the vehicle motion are one or more signals corresponding to motion of the one or more components of the vehicle.

12. The ECG signal processing system of claim 11 wherein the one or more components of the vehicle comprise one or more of a gurney, a vehicle cabin, a vehicle frame, and one or more vehicle suspension components.

13. The ECG signal processing system of claim 12 wherein the processor is further configured to:

receive a signal corresponding to motion of the vehicle cabin and a signal corresponding to motion of the one or more vehicle suspension components, and

process the signal corresponding to the motion of the vehicle cabin and the signal corresponding to the motion of the one or more vehicle suspension components to account for a delay in transmission of vibrations from the one or more vehicle suspension components to the vehicle cabin to estimate the vehicle motion induced artifacts in the measured ECG signal.

14. The ECG signal processing system of claim 12 wherein the processor is further configured to:

receive a signal corresponding to motion of the vehicle frame and a signal corresponding to motion of the one or more vehicle suspension components, and

process the signal corresponding to the motion of the vehicle frame and the signal corresponding to the motion of the one or more vehicle suspension components to account for relative motion between the vehicle frame and the one or more vehicle suspension components to estimate the vehicle motion induced artifacts in the measured ECG signal.

15. The ECG signal processing system of claim 1 wherein the output device comprises a display.

16. The ECG signal processing system of claim 2 wherein the CPR motion sensor comprises one or more of an accelerometer, a velocity sensor, a displacement sensor, and a force sensor.

17. The ECG signal processing system of claim 1 wherein the vehicle comprises a gurney, an ambulance, or a combination thereof.

3. A method of calculating an estimated true ECG signal from a patient undergoing transport provided by a vehicle, said method comprising:

receiving, at a processor, from one or more vehicle motion sensors operably connected to the vehicle and communicatively coupled to the processor, a first input comprising one or more signals corresponding to vehicle motion;

receiving, at the processor, from electrodes communicatively coupled to the processor, a second input comprising a measured ECG signal of the patient;

processing the first input and the second input, by the processor, to determine the estimated true ECG signal; and

outputting, by the processor to an output device, the estimated true ECG signal.

4. The method of claim 3 further comprising:

receiving, at the processor, from a CPR motion sensor communicatively coupled to the processor, a signal corresponding to motion of the chest of the patient during CPR chest compressions; and

processing the signal corresponding to the motion of the chest of the patient during CPR compressions to determine the estimated true ECG signal.

18. The method of claim 3 wherein the output device comprises a display.

19. The method of claim 3, wherein the processing the first input and the second input comprises:

estimating vehicle motion induced artifacts in the measured ECG signal based on the one or more signals corresponding to the vehicle motion; and

determining the estimated true ECG signal by removing the estimated vehicle motion induced artifacts from the measured ECG signal.

20. The method of claim 19 further comprising determining the estimated true ECG signal by subtracting the estimated vehicle motion induced artifacts from the measured ECG signal.

21. The method of claim 19 further comprising estimating the vehicle motion induced artifacts in the measured ECG signal based on a linear predictive filter.

22. The method of claim 21 further comprising identifying the linear predictive filter.

23. The method of claim 19 further comprising estimating the vehicle motion induced artifacts in the measured ECG signal based on a non-linear predictive filter.

24. The method of claim 23 further comprising identifying the non-linear predictive filter.

25. The method of claim 19 wherein the one or more vehicle motion sensors are operably connected to one or more components of the vehicle and wherein the one or more signals corresponding to the vehicle motion are one or more signals corresponding to motion of the one or more components of the vehicle.

26. The method of claim 25 wherein the one or more components of the vehicle comprise one or more of a gurney, a vehicle cabin, a vehicle frame, and one or more vehicle suspension components.

27. The method of claim 26 further comprising:

receiving a signal corresponding to motion of the vehicle cabin and a signal corresponding to motion of the one or more vehicle suspension components; and

estimating the vehicle motion induced artifacts in the measured ECG signal by processing the signal corresponding to the motion of the vehicle cabin motion and the signal corresponding to the motion of the one or more vehicle suspension components to account for a delay in transmission of vibrations from the one or more vehicle suspension components to the vehicle cabin.

28. The method of claim 26 further comprising:

receiving a signal corresponding to motion of the vehicle frame and a signal corresponding to motion of the one or more vehicle suspension components; and

estimating the vehicle motion induced artifacts in the measured ECG signal by processing the signal corresponding to the motion of the vehicle frame and the signal corresponding to the motion of the one or more vehicle suspension components to account for relative motion between the vehicle frame and the one or more vehicle suspension components.

29. The method of claim 3 wherein the vehicle comprises a gurney, an ambulance, or a combination thereof.