SIGNAL PROCESSING TECHNIQUES FOR AIDING THE INTERPRETATION OF RESPIRATION SIGNALS

• US 20130245482A1
• Filed: 05/01/2013
• Published: 09/19/2013
• Est. Priority Date: 06/09/2009
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Addison, Paul Stanley, Watson, James Nicholas, McGonigle, Scott
• Application Number:
  US13/874,975
• Publication Number:
  US 20130245482A1
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

According to embodiments, a respiration signal may be processed to normalize respiratory feature values in order to improve and/or simplify the interpretation and subsequent analysis of the signal. Data indicative of a signal may be received at a sensor and may be used to generate a respiration signal. Signal peaks in the respiration signal may be identified and signal peak thresholds may be determined. The identified signal peaks may be adjusted based on the signal peak threshold values to normalize the respiration signal.

Claims

1. A method for processing a physiological signal, comprising:

receiving, using a processor, the physiological signal;

generating, using the processor, a wavelet transform based at least in part on the physiological signal, wherein the wavelet transform comprises phase information;

identifying, using the processor, phase values corresponding to respiration based at least in part on the wavelet transform; and

generating, using the processor, a substantially sinusoidal function based at least in part on the phase values, wherein the substantially sinusoidal function is indicative of respiration phase.

2. The method of claim 1, wherein the substantially sinusoidal function comprises normalized height values.

3. The method of claim 1, wherein identifying the phase values comprises identifying a respiration ridge based at least in part on the wavelet transform.

4. The method of claim 3, wherein the respiration ridge comprises local phase values as a function of time.

5. The method of claim 1, wherein generating the sinusoidal function comprises determining the cosine or sine of the phase values.

6. The method of claim 1, wherein generating the sinusoidal function comprises determining an inverse wavelet transform of the phase values as a function of time.

7. The method of claim 1, further comprising determining a respiration parameter based at least in part on the substantially sinusoidal function.

8. The method of claim 1, further comprising generating a display based at least in part on the substantially sinusoidal function.

9. The method of claim 8, wherein the display comprises a bar graph.

10. The method of claim 1, wherein the physiological signal is a photoplethysmograph signal.

11. A system for processing a physiological signal, comprising:

a processor configured to perform operations comprising;

receiving the physiological signal;

generating a wavelet transform based at least in part on the physiological signal, wherein the wavelet transform comprises phase information;

identifying phase values corresponding to respiration based at least in part on the wavelet transform; and

generating a substantially sinusoidal function based at least in part on the phase values, wherein the substantially sinusoidal function is indicative of respiration phase.

12. The system of claim 11, wherein the substantially sinusoidal function comprises normalized height values.

13. The system of claim 11, wherein identifying the phase values comprises identifying a respiration ridge based at least in part on the wavelet transform.

14. The system of claim 13, wherein the respiration ridge comprises local phase values as a function of time.

15. The system of claim 11, wherein generating the sinusoidal function comprises determining the cosine or sine of the phase values.

16. The system of claim 11, wherein generating the sinusoidal function comprises determining an inverse wavelet transform of the phase values as a function of time.

17. The system of claim 11, wherein the processor is configured to perform operations further comprising determining a respiration parameter based at least in part on the substantially sinusoidal function.

18. The system of claim 11, wherein the processor is configured to perform operations further comprising generating a display based at least in part on the substantially sinusoidal function.

19. The system of claim 18, wherein the display comprises a bar graph.

20. The system of claim 11, wherein the physiological signal is a photoplethysmograph signal.

21. A method for processing a respiration signal, comprising:

obtaining, using a processor, the respiration signal;

determining, using the processor, one or more signal thresholds for the respiration signal based at least in part on the respiration signal;

identifying, using the processor, one or more portions of the respiration signal that exceed at least one of the one or more signal thresholds;

selectively adjusting, using the processor, the amplitude of the respiration signal based at least in part on the identified one or more portions to generate an adjusted respiration signal, wherein the amplitude of at least one peak in the respiration signal is adjusted; and

determining, using the processor, a respiration parameter based at least in part on the adjusted respiration signal.

22. The method of claim 21, wherein the one or more signal thresholds comprise an upper threshold and a lower threshold, wherein selectively adjusting comprises reducing the amplitude of the at least one peak, and wherein at least one other peak below the lower threshold remains unadjusted.