Periodic disordered breathing detection

• US 20070239057A1
• Filed: 03/29/2006
• Published: 10/11/2007
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation), Mediacell Licensing Corporation
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lin, Zheng, Kwok, Jonathan, Lee, Kent, Pu, Yanchuan
• Granted Patent: US 7,819,816 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61N 1/3601 of respiratory organs

Abstract

Systems and methods are directed to evaluating breathing disorders, such as periodic disordered breathing. A signal representative of patient respiration is developed, typically patient-internally. An envelope of the signal is provided. Periodicity of the envelope is detected, and presence and severity of periodic disordered breathing is determined based on the periodicity of the envelope.

Claims

1. A method, comprising:

developing, patient internally, a signal representative of patient respiration;

providing an envelope of the signal;

detecting periodicity of the envelope; and

determining presence of periodic disordered breathing based on the periodicity of the envelope.

2. The method of claim 1, wherein providing the envelope of the signal comprises squaring and low pass filtering the signal.

3. The method of claim 1, wherein providing the envelope of the signal comprises performing peak detection on the signal or downsampling the signal.

4. The method of claim 1, wherein detecting periodicity of the envelope comprises determining regularity of envelope periodicity.

5. The method of claim 4, wherein determining regularity of envelope periodicity comprises computing a standard deviation (K_SD) of duration for n envelope cycles occurring within a time window having a predetermined duration.

6. The method of claim 5, wherein envelope periodicity is determined if the standard deviation (K_SD) is less than a first threshold and n is greater than a second threshold.

7. The method of claim 1, wherein determining presence of periodic disordered breathing comprises determining regularity of envelope periodicity and a duration of envelope cycles occurring within a time window of predetermined duration.

8. The method of claim 1, wherein determining presence of periodic disordered breathing comprises computing, within a time window of predetermined duration, a mean (K_MEAN) indicative of average envelope cycle length and a standard deviation (K_SD) of the mean (K_MEAN) computed for n envelope cycles occurring within the time window.

9. The method of claim 8, wherein presence of periodic disordered breathing is determined if the standard deviation (K_SD) is less than a first threshold, n is greater than a second threshold, and K_MEAN falls within a third threshold range.

10. The method of claim 1, further comprising computing a number of periodic disordered breathing events occurring within a time window of predetermined duration by dividing the predetermined duration by a mean (K_MEAN) indicative of average envelope cycle length.

11. The method of claim 10, further comprising computing an estimated apnea-hypopnea index based on the number of periodic disordered breathing events occurring within each of a plurality of the time windows, a total duration of the plurality of time windows defining a duration of patient sleep.

12. The method of claim 1, further comprising determining severity of the periodic disordered breathing.

13. The method of claim 12, wherein determining the severity of the periodic disordered breathing comprises distinguishing between central sleep apnea and obstructive sleep apnea.

14. The method of claim 12, wherein determining the severity of the periodic disordered breathing comprises determining the severity of a patient'"'"'s heart failure condition by determining presence of the periodic disordered breathing in each of a plurality of physiological states.

15. The method of claim 12, wherein determining the severity of the periodic disordered breathing comprises determining a frequency of the periodicity and a stability of the periodicity.

16. The method of claim 12, wherein determining the severity of the periodic disordered breathing comprises determining a depth of a change in peaks of the envelope.

17. The method of claim 1, wherein the signal representative of patient respiration comprises a respiratory-modulated physiological signal.

18. The method of claim 1, wherein each of providing, detecting, and determining is performed patient internally.

19. A system, comprising:

an implantable housing;

detection circuitry provided in the housing and configured to detect a signal representative of patient respiration; and

a processor configured to detect periodicity of an envelope of the signal and determine presence of periodic disordered breathing based on the periodicity of the envelope.

20. The system of claim 19, wherein the processor is disposed in the implantable housing.

21. The system of claim 19, wherein the processor is disposed in a patient-external system.

22. The system of claim 19, wherein the processor is configured to detect regularity of envelope periodicity.

23. The system of claim 19, wherein the processor is configured to determining a duration of envelope periodicity.

24. The system of claim 19, wherein the processor is configured to compute an estimated apnea-hypopnea index based on the periodicity of the envelope.

25. The system of claim 19, wherein the processor is configured to determine severity of the periodic disordered breathing.

26. A system, comprising:

means for developing a signal representative of patient respiration from within a patient;

means for detecting periodicity of an envelope of the signal; and

means for determining presence of periodic disordered breathing based on the periodicity of the envelope.