Systems And Methods For Autonomic Nervous System Monitoring

• US 20120253140A1
• Filed: 03/30/2011
• Published: 10/04/2012
• Est. Priority Date: 03/30/2011
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett Ireland
• Original Assignee: Nellcor Puritan Bennett Ireland
• Inventors: Addison, Paul S., Watson, James N.
• Application Number:
  US13/076,281
• Publication Number:
  US 20120253140A1
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• 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 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms

Abstract

Methods and systems are disclosed for determining physiological information about a patient'"'"'s autonomic nervous system based on at least one physiological signal measured from the patient and at least one known characteristic of a patient'"'"'s respiration. Respiration protocol may be provided to guide characteristics of the patient'"'"'s respiration. The physiological signal measured from the patient may be transformed using a wavelet transform to create a transformed signal, and a scalogram may be generated based at least in part on the transformed signal. A metric that may indicate information about the patient'"'"'s autonomic nervous system may be determined from the scalogram and the known characteristic of the patient'"'"'s respiration.

Claims

1. A method for determining physiological information about a subject, the method comprising:

receiving a physiological signal affected by a patient'"'"'s respiration, wherein at least one characteristic of the patient'"'"'s respiration is known;

transforming the physiological signal using processing equipment into a transformed signal; and

determining using the processing equipment, information about the patient'"'"'s autonomic nervous system based at least in part on the transformed signal and the at least one characteristic of the patient'"'"'s respiration.

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

3. The method of claim 1, wherein a known characteristic of the patient'"'"'s respiration is derived from a respiration protocol.

4. The method of claim 1, wherein the at least one characteristic of the patient'"'"'s respiration comprises respiration rate, volume of inhalation, volume of exhalation, length of inhalation, length of exhalation, time between inhalation and exhalation, time of inhalation, and/or time of exhalation, and/or a combination thereof.

5. The method of claim 1, wherein the transforming the physiological signal comprises transforming the physiological signal using a wavelet transform;

and further comprising generating a scalogram based at least in part on the transformed signal.

6. The method of claim 1, wherein the determining is based at least in part on respiratory sinus arrhythmia.

7. The method of claim 1, wherein the determining comprises analyzing the transformed signal to identify the at least one metric associated with the patient'"'"'s autonomic nervous system response.

8. The method of claim 7, wherein the at least one metric comprises a time delay between the patient'"'"'s respiratory activity and a corresponding change in morphology of the transformed signal associated with the patient'"'"'s autonomic nervous system response to the respiratory activity.

9. A system for determining physiological information about a subject, the system comprising:

an input configured to receive a physiological signal being affected by a patient'"'"'s respiration, wherein at least one characteristic of the patient'"'"'s respiration is known;

processing equipment configured to;

transform the physiological signal into a transformed signal; and

determine, based at least in part on the transformed signal and the at least one characteristic of the patient'"'"'s respiration, information about the patient'"'"'s autonomic nervous system.

10. The system of claim 9, wherein the physiological signal is a photoplethysmograph signal.

11. The system of claim 9, wherein a known characteristic of the patient'"'"'s respiration is derived from a respiration protocol.

12. The system of claim 9, wherein the at least one characteristic of the patient'"'"'s respiration comprises respiration rate, volume of inhalation, volume of exhalation, length of inhalation, length of exhalation, time between inhalation and exhalation, time of inhalation, and/or time of exhalation, and/or a combination thereof.

13. The system of claim 9, wherein the processing equipment is configured to transform the physiological signal using a wavelet transform;

and to generate a scalogram based at least in part on the transformed signal.

14. The system of claim 9, wherein the processing equipment is configured to determine information about the patient'"'"'s autonomic nervous system based at least in part on respiratory sinus arrhythmia.

15. The system of claim 13, wherein the processing equipment is configured to determine information about a patient'"'"'s autonomic nervous system by analyzing the transformed signal to identify the at least one metric associated with the patient'"'"'s autonomic nervous system response.

16. The system of claim 15, wherein the metric comprises a time delay between the patient'"'"'s respiratory activity and a corresponding change in morphology of the transformed signal associated with the patient'"'"'s autonomic nervous system response to the respiratory activity.

17. A computer-readable medium having stored instructions that when executed direct:

an input port to receive a physiological signal affected by a patient'"'"'s respiration, wherein at least one characteristic of the patient'"'"'s respiration is known; and

processing equipment to;

transform the physiological signal into a transformed signal; and

determine, based at least in part on the transformed signal and the at least one characteristic of the patient'"'"'s respiration, information about the patient'"'"'s autonomic nervous system.

18. The computer-readable medium of claim 17, wherein the physiological signal is a photoplethysmograph signal.

19. The computer-readable medium of claim 17, wherein a known characteristic of the patient'"'"'s respiration is derived from a respiration protocol.

20. The computer-readable medium of claim 17, wherein the at least one characteristic of the patient'"'"'s respiration comprises respiration rate, volume of inhalation, volume of exhalation, length of inhalation, length of exhalation, time between inhalation and exhalation, time of inhalation, and/or time of exhalation, and/or a combination thereof.

21. The computer-readable medium of claim 17, wherein the processing equipment is directed to transform the physiological signal using a wavelet transform;

and to generate a scalogram based at least in part on the transformed signal.

22. The computer-readable medium of claim 17, wherein the processing equipment is directed to determine information about the patient'"'"'s autonomic nervous system based at least in part on respiratory sinus arrhythmia.

23. The computer-readable medium of claim 21, wherein the determining comprises analyzing the transformed signal to identify at least one metric associated with the patient'"'"'s autonomic nervous system response;

and wherein the metric comprises a time delay between the patient'"'"'s respiratory activity and a corresponding change in morphology of the transformed signal associated with the patient'"'"'s autonomic nervous system response to the respiratory activity.