Periodic disordered breathing detection

• US 7,819,816 B2
• Filed: 03/29/2006
• Issued: 10/26/2010
• Est. Priority Date: 03/29/2006
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation), Mediacell Licensing Corporation
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lin, Zheng, Pu, Yanchuan, Kwok, Jonathan, Lee, Kent
• Primary Examiner(s): Mallari; Patricia C
• Application Number:
  US11/392,365
• Publication Number:
  US 20070239057A1
• Time in Patent Office: 1,672 Days
• Field of Search: 600/345, 600/347, 600/365, 600/484, 600/508, 600/529, 204/403.01
• 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 by computing a parameter characterizing envelope cycle length for multiple envelope cycles occurring within a time window, the parameter comprising one or both of a standard deviation (K_SD) of duration for n envelope cycles and a duration of the time window divided by a mean (K_MEAN) indicative of average envelope cycle length, wherein developing, detecting, and determining are performed at least in part by circuitry, and wherein n is a number.

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 1, wherein the parameter comprises the standard deviation (K_SD) parameter and the envelope periodicity is determined based on the standard deviation (K_SD) being less than a first threshold and n being greater than a second threshold.

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

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

8. The method of claim 7, wherein the 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.

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

10. The method of claim 9, 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.

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

12. The method of claim 11, wherein determining the severity of the periodic disordered breathing comprises distinguishing between central sleep apnea and obstructive sleep apnea.

13. The method of claim 11, wherein determining the severity of the periodic disordered breathing comprises determining the severity of a patient'"'"'s heart failure condition by determining the presence of the periodic disordered breathing in each of a plurality of physiological states.

14. The method of claim 11, wherein determining the severity of the periodic disordered breathing comprises determining a frequency of the periodicity and a stability of the periodicity.

15. The method of claim 11, wherein determining the severity of the periodic disordered breathing comprises determining a depth of a change in peaks of the envelope.

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

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

18. The method of claim 1, further comprising one or more of generating an alert, initiating a therapy, and changing delivery of the therapy in response to determination of presence of periodic disordered breathing.

21. The method of claim 18, further comprising one or more of generating an alert, initiating a therapy, and changing delivery of the therapy in response to determination of presence of periodic disordered breathing.

19. A method, comprising:

developing a signal representative of patient respiration;

providing an envelope of the signal;

determining periodicity of the envelope; and

determining presence of periodic disordered breathing based on the periodicity of the envelope by computing a standard deviation (K_SD) of duration for n envelope cycles characterizing envelope cycle length for multiple envelope cycles occurring within a time window, wherein at least one of determining periodicity and determining presence is performed at least in part by circuitry, and wherein n is a number.

20. The method of claim 19, wherein developing, providing, determining periodicity, and determining presence are performed patient internally.

22. A method, comprising:

developing a signal representative of patient respiration;

providing an envelope of the signal;

determining periodicity of the envelope; and

determining presence of periodic disordered breathing based on the periodicity of the envelope by computing a parameter characterizing envelope cycle length for multiple envelope cycles occurring within a time window, the parameter comprising the time window duration divided by a mean (K_MEAN) indicative of average envelope cycle length, wherein at least one of determining periodicity and determining presence is performed at least in part by circuitry.

23. The method of claim 22, wherein developing, providing, determining periodicity, and determining presence are performed patient internally.

24. The method of claim 22, further comprising one or more of generating an alert, initiating a therapy, and changing delivery of the therapy in response to determination of presence of periodic disordered breathing.