FALSE POSITIVE REDUCTION IN SPO2 ATRIAL FIBRILLATION DETECTION USING AVERAGE HEART RATE AND NIBP

• US 20080269626A1
• Filed: 04/30/2007
• Published: 10/30/2008
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Gallagher, Scott Patrick, Sitzman, David Alan
• Granted Patent: US 7,806,832 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence

Abstract

The method and system includes detecting atrial fibrillation in a patient by monitoring the blood oxygen saturation level over a period of time. The method and system produces a plethysmographic waveform from the monitored blood oxygen saturation level and analyzes the plethysmographic waveform and detected intervals and determines whether the patient is in atrial fibrillation. The method and system is preferably implemented in a software application and may be configured to report to the user on the current state of atrial fibrillation (AFIB) and a current trend.

Claims

1. A method of detecting atrial fibrillation in a human or animal subject, the method comprising:

acquiring a plethysmographic waveform of a patient from a monitoring device over a period of time;

extracting a pulse from the plethysmographic waveform;

measuring a set of pulse intervals from the plethysmographic waveform;

measuring a set of features from the plethysmographic waveform;

analyzing the set of pulse intervals and the set of pulse features from the plethysmographic waveform to determine an atrial fibrillation state of the patient; and

analyzing the pulse from the plethysmographic waveform to confirm the atrial fibrillation state of the patient.

2. The method as claimed in claim 1, wherein the monitoring device is a pulse oximeter sensor.

3. The method as claimed in claim 1, wherein one of the set of features is a set of pulse amplitudes.

4. The method as claimed in claim 1, further comprising analyzing the set of pulse intervals and the set of pulse features from the plethysmographic waveform to detect an atrial fibrillation trend of the patient.

5. The method as claimed in claim 4, further comprising reporting the atrial fibrillation trend.

6. The method as claimed in claim 1, further comprising reporting the atrial fibrillation state.

7. The method as claimed in claim 1, wherein analyzing the pulse includes:

conducting an average heart rate analysis; and

an average heart rate variability analysis.

8. The method as claimed in claim 1, further comprising acquiring and analyzing an NIBP pulse of the patient.

9. The method as claimed in claim 1, further comprising acquiring and analyzing a set of medical records of the patient.

10. The method as claimed in claim 1, wherein analyzing the set of pulse intervals includes:

conducting a hidden Markov model analysis on the set of pulse intervals; and

conducting a contextual analysis on the set of pulse intervals.

11. The method as claimed in claim 10, wherein the hidden Markov model analysis determines a probability of the patient having an irregular heart rhythm.

12. The method as claimed in claim 10, wherein the contextual analysis rules out atrial fibrillation as a source of irregular heart rhythm.

13. The method as claimed in claim 1, wherein analyzing the set of pulse features includes:

calculating amplitude variation between each consecutive one of the set of pulse amplitudes.

14. The method as claimed in claim 13, wherein the atrial fibrillation state determination is dependent on an analysis of pulse amplitude variation.

15. The method as claimed in claim 1, wherein analyzing the set of pulse amplitudes includes determining a set of filling time dynamics of the set of pulse amplitudes.

16. The method as claimed in claim 15, wherein the steps of analyzing the set of pulse amplitudes and determining the set of filling time dynamics provides an indication of the degree of atrial augmentation present.

17. The method as claimed in claim 1, wherein the pulse analyzing step contributes to determining the atrial fibrillation state of the patient.

18. A system for detecting atrial fibrillation in a human or animal subject, the system comprising:

a remote sensing system configured to analyze a plethysmographic waveform from a first monitoring device, and further configured to analyze an NIBP pulse from a second monitoring device;

a storage media for storing a computer application;

a processing unit coupled to the remote sensing system and the storage media, and configured to execute the computer application, and further configured to receive the plethysmographic waveform and the NIBP pulse from the remote sensing system,

wherein when the computer application is executed, a pulse and a set of pulse intervals from the plethysmographic waveform are detected, and a set of pulse features are measured from the plethysmographic waveform, and further wherein the set of pulse intervals and the set of pulse features are analyzed to determine an atrial fibrillation state of the patient, and the pulse and the NIBP pulse are analyzed to confirm the atrial fibrillation state of the patient.

19. The system as claimed in claim 18, wherein the monitoring device is a pulse oximeter sensor.

20. The system as claimed in claim 18, further wherein when the set of pulse intervals and the set of pulse features from the plethysmographic waveform are analyzed, an atrial fibrillation trend of the patient is detected.

21. The system as claimed in claim 20, further comprising means for reporting the atrial fibrillation trend to the patient.

22. The system as claimed in claim 18, further comprising means for reporting the atrial fibrillation state.

23. The system as claimed in claim 18, wherein when the computer application is executed and the pulse is analyzed, an average heart rate analysis and an average heart rate variability is conducted on the pulse.

24. The system as claimed in claim 18, wherein the NIBP pulse is analyzed to the atrial fibrillation state of the patient.

25. The system as claimed in claim 18, wherein when the computer application is executed, a set of medical records are acquired and analyzed to either determine of confirm the atrial fibrillation state of the patient.

26. The system as claimed in claim 18, wherein when the computer application is executed and the set of pulse intervals is analyzed, a hidden Markov model analysis is conducted on the set of pulse intervals, and a contextual analysis is conducted on the set of pulse intervals.

27. The system as claimed in claim 26, wherein the hidden Markov model analysis determines a probability of the patient having an irregular heart rhythm.

28. The system as claimed in claim 26, wherein the contextual analysis rules out atrial fibrillation as a source of irregular heart rhythm.

29. The system as claimed in claim 18, wherein when the computer application is executed and the set of pulse features is analyzed, the filling time dynamics of the set of pulse features is determined, and feature variation between each one of the set of pulse features is calculated relative to the mean, the median, consecutive pulses, or maximum to minimum.

30. The system as claimed in claim 29, wherein the atrial fibrillation state determination is dependent on an analysis of pulse amplitude variation.

31. The system as claimed in claim 30, wherein the analysis of pulse amplitude variation as a function of filling time provides an indication of the degree of atrial augmentation present.

32. A method of detecting atrial fibrillation, the method comprising:

producing a plethysmographic waveform from a plethysmographic sensor;

extracting a pulse from the plethysmographic waveform;

detecting a set of pulse intervals from the plethysmographic waveform;

measuring a set of pulse features from the plethysmographic waveform;

analyzing the set of pulse intervals and the set of pulse features from the plethysmographic waveform to determine an atrial fibrillation state of the patient and to detect an atrial fibrillation trend of the patient;

analyzing the pulse from the plethysmographic waveform, and an NIBP pulse and a set of medical records to confirm the atrial fibrillation state of the patient; and

reporting the atrial fibrillation state and the atrial fibrillation trend to the patient,

wherein analyzing the pulse includes conducting an average heart rate analysis and an average heart rate variability analysis.