Detection and Monitoring of Stress Events During Sleep

• US 20080269583A1
• Filed: 02/07/2006
• Published: 10/30/2008
• Est. Priority Date: 02/07/2005
• Status: Abandoned Application

• Current Assignee: Widemed Ltd.
• Original Assignee: Widemed Ltd.
• Inventors: Reisfeld, Daniel
• Application Number:
  US11/883,471
• Publication Number:
  US 20080269583A1
• Time in Patent Office: Days
• US Class Current: 600/364
• 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 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

A computer-implemented method for monitoring a patient (22) includes receiving physiological signals from the patient during sleep and processing at least one of the signals to detect a spontaneous stress event. One or more of the signals following the stress event are analyzed so as to evaluate a stress response of the patient.

Claims

1. A computer-implemented method for monitoring a patient, comprising:

receiving a signal associated with respiration of the patient during sleep;

processing the signal to detect a pattern of periodic breathing;

extracting from the signal a shape characteristic of the pattern; and

classifying an etiology of the periodic breathing responsively to the shape characteristic.

2. The method according to claim 1, wherein classifying the etiology comprises determining the periodic breathing to be predominantly central or obstructive in origin.

3. The method according to claim 2, wherein extracting the shape characteristic comprises computing a parameter that is characteristic of a symmetry of the pattern.

4. The method according to claim 3, wherein determining the periodic breathing comprises classifying the periodic breathing as predominantly central in origin if the pattern is symmetrical.

5. The method according to claim 1, wherein receiving the signal comprises receiving an indication of least one of a flow through an airway of the patient, a movement of an abdomen or thorax of the patient, a heart rate of the patient, a respiration rate of the patient, a blood flow of the patient, a blood oxygen saturation level of the patient, and a pulse transit time (PTT) of the patient.

6. The method according to claim 1, wherein receiving the signal comprises receiving a photoplethysmographic signal from an organ of the patient.

7. The method according to claim 6, wherein receiving the signal comprises fastening a belt holding a reflective photoplethysmographic sensor around the patient, and measuring both a respiratory movement and a blood oxygen saturation level of the patient using the belt and photoplethysmographic sensor.

8. The method according to claim 1, wherein the pattern comprises a hyperventilation interval and a hypoventilation interval, and wherein extracting the shape characteristic comprises fitting first and second waveforms to the hyperventilation and hypoventilation intervals, respectively.

9. The method according to claim 8, wherein the first and second waveforms comprise analytical functions.

10. The method according to claim 9, wherein the analytical functions comprise polynomial waveforms.

11. The method according to claim 9, wherein the analytical functions comprise tilted parabolic waveforms.

12. The method according to claim 8, and comprising extracting features from the signal responsively to the first and second waveforms, and selecting a treatment to administer to the patient based on the extracted features.

13. A computer-implemented method for monitoring a patient, comprising:

receiving physiological signals from the patient during sleep;

processing at least one of the signals to detect a spontaneous stress event; and

analyzing one or more of the signals following the stress event so as to evaluate a stress response of the patient.

14. The method according to claim 13, wherein receiving the physiological signals comprises receiving an indication of least one of a flow through an airway of the patient, a movement of an abdomen or thorax of the patient, a heart rate of the patient, a respiration rate of the patient, a blood flow of the patient, a blood oxygen saturation level of the patient, and a pulse transit time (PTT) of the patient.

15. The method according to claim 13, wherein the spontaneous stress event comprises at least one of an apnea and a hypopnea.

16. The method according to claim 15, wherein analyzing the one or more of the signals comprises assessing a periodic breathing pattern associated with the at least one of the apnea and the hypopnea.

17. The method according to claim 13, wherein receiving the physiological signals comprises receiving a photoplethysmographic signal from an organ of the patient.

18. The method according to claim 17, wherein receiving the physiological signals comprises fastening a belt holding a reflective photoplethysmographic sensor around the patient, and measuring a movement of the thorax and at least one of a blood flow of the patient and a blood oxygen saturation level of the patient using the belt and photoplethysmographic sensor.

19. The method according to claim 18, wherein receiving the physiological signals comprises receiving an electrocardiogram (ECG) signal from a Holter monitor coupled to the patient.

20. The method according to claim 13, wherein analyzing the one or more of the signals comprises detecting a change in the signals relative to a baseline, and alerting at least one of the patient and a medical caregiver of the change.

21. The method according to claim 13, wherein receiving the physiological signals comprises collecting the signals from the patient at a first location where the patient is sleeping, and transmitting the signals over a communication network, and

wherein analyzing the one or more of the signals comprises receiving the one or more of the signals over the communication network at a second location, remote from the first location, and analyzing the received signals at the second location.

22. Apparatus for monitoring a patient, comprising:

a sensor, which is coupled to produce a signal associated with respiration of the patient during sleep; and

a diagnostic processor, which is arranged to process the signal to detect a pattern of periodic breathing, to extract from the signal a shape characteristic of the pattern, and to classify an etiology of the periodic breathing responsively to the shape characteristic.

23. The apparatus according to claim 22, wherein the processor is arranged to determine the periodic breathing to be predominantly central or obstructive in origin.

24. The apparatus according to claim 23, wherein the shape characteristic comprises a parameter that is characteristic of a symmetry of the pattern.

25. The apparatus according to claim 24, wherein the processor is arranged to classify the periodic breathing as predominantly central in origin if the pattern is symmetrical.

26. The apparatus according to claim 22, wherein the signal is indicative of least one of a flow through an airway of the patient, a movement of an abdomen or thorax of the patient, a heart rate of the patient, a respiration rate of the patient, a blood flow of the patient, a blood oxygen saturation level of the patient, and a pulse transit time (PTT) of the patient.

27. The apparatus according to claim 22, wherein the sensor comprises a photoplethysmographic sensor.

28. The apparatus according to claim 27, and comprising a belt, which is configured to hold the photoplethysmographic sensor and to be fastened around the patient, wherein the photoplethysmographic sensor comprises a reflective photoplethysmographic sensor, which is arranged to measure at least one of a blood flow and a blood oxygen saturation level of the patient, and the sensor is also coupled to the belt so as to measure a respiratory movement of the patient using the belt.

29. The apparatus according to claim 28, and comprising a Holter monitor, which is coupled to convey an electrocardiogram (ECG) signal from the patient to the diagnostic processor.

30. The apparatus according to claim 22, wherein the pattern comprises a hyperventilation interval and a hypoventilation interval, and wherein the processor is arranged to fit first and second waveforms to the hyperventilation and hypoventilation intervals, respectively.

31. The apparatus according to claim 30, wherein the first and second waveforms comprise analytical functions.

32. The apparatus according to claim 31, wherein the analytical functions comprise polynomial waveforms.

33. The apparatus according to claim 31, wherein the analytical functions comprise tilted parabolic waveforms.

34. The apparatus according to claim 30, wherein the processor is arranged to extract features from the signal responsively to the first and second waveforms, and to determine a treatment to administer to the patient based on the extracted features.

35. Apparatus for monitoring a patient, comprising:

a sensor, which is coupled to receive physiological signals from the patient during sleep; and

a diagnostic processor, which is arranged to process at least one of the signals to detect a spontaneous stress event, and to analyze one or more of the signals following the stress event so as to evaluate a stress response of the patient.

36. The apparatus according to claim 35, wherein the physiological signals comprises an indication of least one of a flow through an airway of the patient, a movement of an abdomen or thorax of the patient, a heart rate of the patient, a respiration rate of the patient, a blood flow of the patient, a blood oxygen saturation level of the patient, and a pulse transit time (PTT) of the patient.

37. The apparatus according to claim 35, wherein the spontaneous stress event comprises at least one of an apnea and a hypopnea.

38. The apparatus according to claim 37, wherein the processor is arranged to assess a periodic breathing pattern associated with the at least one of the apnea and the hypopnea.

39. The apparatus according to claim 35, wherein the sensor comprises a photoplethysmographic sensor.

40. The apparatus according to claim 39, and comprising a belt, which is configured to hold the photoplethysmographic sensor and to be fastened around the patient, wherein the photoplethysmographic sensor comprises a reflective photoplethysmographic sensor, which is arranged to measure at least one of a blood flow and a blood oxygen saturation level of the patient, and the sensor is also coupled to the belt so as to measure a respiratory movement of the patient using the belt.

41. The apparatus according to claim 40, wherein the processor is arranged to detect a change in the signals relative to a baseline, and to alert at least one of the patient and a medical caregiver of the change.

42. The apparatus according to claim 40, wherein the sensor is operative to collect the signals from the patient at a first location where the patient is sleeping, and comprising a console, which is coupled to receive the signals from the sensor and to transmit the signals over a communication network, and

wherein the processor is coupled to receive the signals over the communication network at a second location, remote from the first location, and to analyze the received signals at the second location.

43. Apparatus for monitoring a patient, comprising:

a belt, which is adapted to be fastened around a body of the patient; and

a sensor unit, which is coupled to the belt so as to sense a respiratory motion of the patient, and which comprises a photoplethysmographic sensor, which is held against the body by the belt and is arranged to measure at least one of a blood flow and a blood oxygen saturation level of the patient.

44. The apparatus according to claim 43, wherein the belt is configured to be fastened around a thorax of the patient, and wherein the photoplethysmographic sensor comprises a reflective sensor.