METHODS AND SYSTEMS FOR DETERMINING PHYSIOLOGICAL INFORMATION BASED ON STATISTICAL REGRESSION ANALYSIS

• US 20140073940A1
• Filed: 09/11/2012
• Published: 03/13/2014
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Rodriguez-Llorente, Fernando, Engelbrecht, Pirow, Wooder, Nicholas James
• Granted Patent: US 9,226,670 B2
• Time in Patent Office: Days
• US Class Current: 600/476
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 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 6/5217 extracting a diagnostic or physiological parameter from medical diagnostic data
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012

Abstract

A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may select two segments of the physiological signal, shifted in time relative to one another by a lag value, and determine a correlation value between the two segments. The system may determine a metric based on the segments, and determine correlation information based on the correlation value and the metric. The metric may be indicative of how well the segments are correlated, providing additional information relative to the correlation value. Based on the metric, the system may modify the correlation value, determine a confidence value, or determine other information. The system may determine physiological rate information based on the correlation information.

Claims

1. A subject monitoring system for processing physiological information of a subject, comprising:

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

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

select a first segment of the physiological signal comprising a plurality of values;

select a second segment of the physiological signal comprising a plurality of values, wherein the second segment is shifted in time from the first segment;

determine a correlation value between the first segment and the second segment;

analyze the first segment and the second segment to determine a metric; and

determine correlation information based on the correlation value and based on the metric.

2. The system of claim 1, wherein the processing equipment is further configured to modify the correlation value based on the metric.

3. The system of claim 1, wherein the processing equipment is further configured to:

select multiple segments of the physiological signal each comprising a plurality of values;

determine multiple correlation values between the first segment and the multiple segments, wherein the multiple segments are each shifted in time from the first segment by a unique lag; and

determine that the correlation value corresponds to a peak in the multiple correlation values.

4. The system of claim 1, wherein the processing equipment is further configured to generate a plurality of value pairs each comprising a value of the first segment and a corresponding value of the second segment.

5. The system of claim 4, wherein the processing equipment is further configured to determine a metric based on the plurality of value pairs and a reference relationship.

6. The system of claim 4, wherein the processing equipment is further configured to:

apply a transform to the plurality of value pairs to generate a plurality of transformed value pairs comprising a first value and a second value; and

analyze the distribution across the plurality of first values of each transformed value pairs.

7. The system of claim 1, wherein the metric is a confidence value, and wherein the processing equipment is further configured to generate a modified confidence value by multiplying the correlation value and the metric.

8. A processing module for processing physiological information of a subject, wherein the processing module is configured to:

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

select a first segment of the physiological signal comprising a plurality of values;

select a second segment of the physiological signal comprising a plurality of values, wherein the second segment is shifted in time from the first segment;

determine a correlation value between the first segment and the second segment;

analyze the first segment and the second segment to determine a metric; and

determine correlation information based on the correlation value and based on the metric.

9. The processing module of claim 8, further configured to modify the correlation value based on the metric.

10. The processing module of claim 8, further configured to:

select multiple segments of the physiological signal each comprising a plurality of values;

determine multiple correlation values between the first segment and the multiple segments, wherein the multiple segments are each shifted in time from the first segment by a unique lag; and

determine that the correlation value corresponds to a peak in the multiple correlation values.

11. The processing module of claim 8, further configured to generate a plurality of value pairs each comprising a value of the first segment and a corresponding value of the second segment.

12. The processing module of claim 11, further configured to determine a metric based on the plurality of value pairs and a reference relationship.

13. The processing module of claim 11, further configured to:

apply a transform to the plurality of value pairs to generate a plurality of transformed value pairs comprising a first value and a second value; and

analyze the distribution across the plurality of first values of each transformed value pairs.

14. The processing module of claim 8, wherein the metric is a confidence value, the processing module further configured to generate a modified confidence value by multiplying the correlation value and the metric.

15. A method for processing physiological information of a subject, comprising:

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

selecting, using the processing equipment, a first segment of the physiological signal comprising a plurality of values;

selecting, using the processing equipment, a second segment of the physiological signal comprising a plurality of values, wherein the second segment is shifted in time from the first segment;

determining, using the processing equipment, a correlation value between the first segment and the second segment;

analyzing, using the processing equipment, the first segment and the second segment to determine a metric; and

determining, using the processing equipment, correlation information based on the correlation value and based on the metric.

16. The method of claim 15, wherein determining correlation information comprises modifying the correlation value based on the metric.

17. The method of claim 15, further comprising

selecting multiple segments of the physiological signal each comprising a plurality of values;

and

determining multiple correlation values between the first segment and the multiple segments, wherein the multiple segments are each shifted in time from the first segment by a unique lag, and wherein determining correlation information comprises determining that the correlation value corresponds to a peak in the multiple correlation values.

18. The method of claim 15, wherein analyzing the first segment and the second segment comprises generating a plurality of value pairs each comprising a value of the first segment and a corresponding value of the second segment.

19. The method of claim 18, wherein analyzing the first segment and the second segment further comprises determining a metric based on the plurality of value pairs and a reference relationship.

20. The method of claim 18, wherein analyzing the first segment and the second segment further comprises:

applying a transform to the plurality of value pairs to generate a plurality of transformed value pairs comprising a first value and a second value; and

analyzing the distribution across the plurality of first values of each transformed value pairs.

21. The method of claim 15, wherein the metric is a confidence value, and wherein determining the correlation information comprises generating a modified confidence value by multiplying the correlation value and the metric.

22. A computer-readable medium for use in processing physiological information of a subject, 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 the subject;

selecting a first segment of the physiological signal comprising a plurality of values;

selecting a second segment of the physiological signal comprising a plurality of values, wherein the second segment is shifted in time from the first segment;

determining a correlation value between the first segment and the second segment;

analyzing the first segment and the second segment to determine a metric; and

determining correlation information based on the correlation value and based on the metric.

23. The computer-readable medium of claim 22, having further computer program instructions recorded thereon for modifying the correlation value based on the metric.

24. The computer-readable medium of claim 22, having further computer program instructions recorded thereon for:

selecting multiple segments of the physiological signal each comprising a plurality of values;

determining multiple correlation values between the first segment and the multiple segments, wherein the multiple segments are each shifted in time from the first segment by a unique lag; and

determining that the correlation value corresponds to a peak in the multiple correlation values.

25. The computer-readable medium of claim 22, having further computer program instructions recorded thereon for generating a plurality of value pairs each comprising a value of the first segment and a corresponding value of the second segment.

26. The computer-readable medium of claim 25, having further computer program instructions recorded thereon for determining a metric based on the plurality of value pairs and a reference relationship.

27. The computer-readable medium of claim 22, having further computer program instructions recorded thereon for:

applying a transform to the plurality of value pairs to generate a plurality of transformed value pairs comprising a first value and a second value; and

analyzing the distribution across the plurality of first values of each transformed value pairs.

28. The computer-readable medium of claim 22, wherein the metric is a confidence value, and wherein the computer-readable medium has further computer program instructions recorded thereon for generating