METHODS AND SYSTEMS FOR CONDITIONING A PHYSIOLOGICAL SIGNAL USING AN ADJUSTABLE BANDPASS FILTER

• US 20140073952A1
• Filed: 09/11/2012
• Published: 03/13/2014
• Est. Priority Date: 09/11/2012
• Status: Abandoned Application

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Rodriguez-Llorente, Fernando, Engelbrecht, Pirow, Wooder, Nicholas James
• Application Number:
  US13/609,433
• Publication Number:
  US 20140073952A1
• Time in Patent Office: Days
• US Class Current: 600/479
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence

Abstract

A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may apply a bandpass filter to the physiological signal to assist in the determination of the physiological information. The system may determine a value indicative of a physiological rate and a metric based on the physiological signal. The system may select one or more settings, such as the center frequency and bandwidth, of the bandpass filter based on the rate and based on the metric, and apply the bandpass filter to the physiological signal.

Claims

1. A subject monitoring system for conditioning a physiological intensity signal, comprising:

a sensor configured to generate a physiological signal, wherein the sensor detects light attenuated by a subject; and

processing equipment coupled to the sensor, wherein the processing equipment is configured to;

determine a value indicative of a physiological rate based on the physiological signal;

determine a metric based on the physiological signal;

select one or more bandpass filter settings of a bandpass filter based on the physiological rate and based on the metric; and

apply the bandpass filter with the selected one or more bandpass filter settings to the physiological signal to generate a filtered signal.

2. The system of claim 1, wherein the metric is indicative of noise in the physiological signal.

3. The system of claim 2, wherein the one or more bandpass filter settings comprise a spectral band, and wherein the processing equipment is further configured to select a narrow spectral band when the metric exceeds a threshold.

4. The system of claim 2, wherein the one or more bandpass filter settings comprise a spectral band, and wherein the processing equipment is further configured to select a wide spectral band when the metric is below a threshold.

5. The system of claim 1, wherein the one or more bandpass filter settings comprise a center frequency and wherein the center frequency corresponds to the physiological rate.

6. The system of claim 1, wherein the physiological rate is heart rate of the subject.

7. A processing module for conditioning a physiological intensity signal, wherein the processing module is configured to:

receive a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;

determine a value indicative of a physiological rate based on the physiological signal;

determine a metric based on the physiological signal;

select one or more bandpass filter settings of a bandpass filter based on the physiological rate and based on the metric; and

apply the bandpass filter with the selected one or more bandpass filter settings to the physiological signal to generate a filtered signal.

8. The processing module of claim 7, wherein the metric is indicative of noise in the physiological signal.

9. The processing module of claim 8, wherein the one or more bandpass filter settings comprise a spectral band, and wherein the processing module is further configured to select a narrow spectral band when the metric exceeds a threshold.

10. The processing module of claim 8, wherein the one or more bandpass filter settings comprise a spectral band, and wherein the processing module is further configured to select a wide spectral band when the metric is below a threshold.

11. The processing module of claim 7, wherein the one or more bandpass filter settings comprise a center frequency and wherein the center frequency corresponds to the physiological rate.

12. The processing module of claim 7, wherein the physiological rate is heart rate of the subject.

13. A method for conditioning a physiological intensity signal, comprising:

receiving, using processing equipment, a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;

determining, using the processing equipment, a value indicative of a physiological rate based on the physiological signal;

determining, using the processing equipment, a metric based on the physiological signal;

selecting, using the processing equipment, one or more bandpass filter settings of a bandpass filter based on the physiological rate and based on the metric; and

applying, using the processing equipment, the bandpass filter with the selected one or more bandpass filter settings to the physiological signal to generate a filtered signal.

14. The method of claim 13, wherein the metric is indicative of noise in the physiological signal.

15. The method of claim 14, wherein the one or more bandpass filter settings comprise a spectral band, and wherein selecting the one or more bandpass filter settings comprise selecting a narrow spectral band when the metric exceeds a threshold.

16. The method of claim 14, wherein the one or more bandpass filter settings comprise a spectral band, and wherein selecting the one or more bandpass filter settings comprise selecting a wide spectral band when the metric is below a threshold.

17. The method of claim 13, wherein the one or more bandpass filter settings comprise a center frequency and wherein the center frequency corresponds to the physiological rate.

18. The method of claim 13, wherein the physiological rate is heart rate of the subject.

19. A computer-readable medium for use in conditioning a physiological intensity signal, the computer-readable medium having computer program instructions recorded thereon for:

receiving a physiological signal derived from a detector output, wherein the detector detects light attenuated by a subject;

determining a value indicative of a physiological rate based on the physiological signal;

determining a metric based on the physiological signal;

selecting one or more bandpass filter settings of a bandpass filter based on the physiological rate and based on the metric; and

applying the bandpass filter with the selected one or more bandpass filter settings to the physiological signal to generate a filtered signal.

20. The computer-readable medium of claim 19, wherein the metric is indicative of noise in the physiological signal.

21. The computer-readable medium of claim 20, wherein the one or more bandpass filter settings comprise a spectral band, the computer-readable medium having further computer program instructions recorded thereon for selecting a narrow spectral band when the metric exceeds a threshold.

22. The computer-readable medium of claim 20, wherein the one or more bandpass filter settings comprise a spectral band, the computer-readable medium having further computer program instructions recorded thereon for selecting a wide spectral band when the metric is below a threshold.

23. The computer-readable medium of claim 19, wherein the one or more bandpass filter settings comprise a center frequency and wherein the center frequency corresponds to the physiological rate.

24. The computer-readable medium of claim 19, wherein the physiological rate is heart rate of the subject.