METHOD AND APPARATUS FOR DETECTING RESPIRATORY EFFORT

• US 20120190998A1
• Filed: 01/18/2012
• Published: 07/26/2012
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Armitstead, Jeffrey Peter, Wells, Alicia Kristianne, Richards, Glenn
• Granted Patent: US 10,448,893 B2
• Time in Patent Office: Days
• US Class Current: 600/534
• CPC Class Codes: A61B 5/0826 Detecting or evaluating apnoea events A61B5/4818 takes precedence
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0633 with forehead support
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/583 : by visual feedback

Abstract

Devices and systems provide methods for detecting respiratory related effort from movements associated with the head or face. In one embodiment, a strain signal is measured by one or more sensors. A processor may analyze the head strain signal to detect respiratory related effort. Detection of effort may serve as a basis for identifying sleep disordered breathing events. For example, the analysis may serve as part of a detector to identify central or obstructive apneas or central or obstructive hypopneas. Sensors may be integrated with headgear to support them at desired locations of the face or head. Strain from head movement may be detected by measuring, for example, tension of the headgear or force applied against the headgear. The headgear may serve as an independent support for the sensors or as a component of a respiratory treatment apparatus, such as a mask or cannula.

Claims

1. A method for detecting respiratory related effort comprising:

measuring a head strain signal with a sensor; and

analyzing the head strain signal with a processor to detect respiratory related effort.

2. The method of claim 1 wherein the analyzing comprises a comparison of the head strain signal and a threshold.

3. The method of claim 2 wherein the threshold is derived from a prior head strain signal measured with the sensor.

4. The method of claim 2 further comprising identifying, with the processor, a type of a detected apnea or hypopnea, based on the comparison.

5. The method of claim 4 wherein the type of detected apnea or hypopnea is identified as one of central, obstructive or mixed, depending on a presence of respiratory effort.

6. The method of claim 2 further comprising identifying, with the processor, a respiratory related arousal event based on the comparison.

7. The method of claim 2 wherein the sensor comprises a strain gauge, a piezoresistor, a tensometer or a spring guage.

8. The method of claim 7 wherein the sensor comprises a component of headgear.

9. The method of claim 8, wherein the sensor is configured to detect changes in tension of one or more straps of the headgear.

10. The method of claim 8 wherein the sensor is configured to detect changes in head or face contact compression with a portion of the headgear.

11. The method of claim 7 wherein the sensor comprises a component of headgear for a patient interface for a respiratory treatment apparatus, the patient interface comprising a respiratory mask and a breathable gas conduit.

12. The method of claim 7 wherein the sensor comprises a component of a patient interface for a respiratory treatment apparatus, the patient interface comprising a respiratory mask and a breathable gas conduit.

13. The method of claim 2 further comprising controlling a change to a respiratory treatment variable, based on the analyzing of the head strain signal.

14. The method of claim 13 wherein the respiratory treatment variable comprises pressure and wherein controlling the change to the respiratory treatment variable is further based on an analysis of data derived from an additional sensor.

15. The method of claim 14 wherein respiratory treatment variable is pressure and the additional sensor is a flow sensor.

16. The method of claim 1, wherein the step of analyzing the head strain signal with a processor comprises:

generating a first and a second filtered head strain signals based on the generated head strain signal;

making a comparison based on the first and the second filtered head strain signals, and

generating an indicator of a presence or absence of significant respiratory effort based on the comparison.

17. The method of claim 16, wherein the comparison includes comparing the second filtered head strain signal with a proportion of the first filtered head strain signal.

18. The method of claim 17, wherein the first filtered head strain signal comprises a long term average head strain signal, such as a long term absolute average, and the second filtered head strain signal comprises a short term average head strain signal.

19. The method of claim 16, wherein an obtained indication of significant head strain is used to classify an apnea or a hypopnea as an obstructive event.

20. The method of claim 16, wherein an obtained indication of an absence of a significant head strain is used to classify an apnea or a hypopnea as a central event.

21. The method of claim 16, wherein the first and second filtered head strain signals are derived from a plurality of head strain signals.

22. The method of claim 20, wherein each of the first and the second filtered head strain signals is derived from a combined head strain signal, such as a signal representing a sum of multiple head strain signals.

23. A device for detecting a respiratory related effort comprising:

one or more sensors configured to generate a head strain signal; and

a processor, coupled with the one or more sensors, the processor configured to control detection of respiratory related effort by analysis of the head strain signal.

24. The device of claim 23 wherein the analysis comprises a comparison of the head strain signal and a threshold.

25. The device of claim 23 wherein the threshold is derived from a prior head strain signal measured with the sensor.

26. The device of claim 23 wherein the processor is configured to identify a type of detected apnea or hypopnea as one of central, obstructive or mixed, depending on the presence of respiratory effort.

27. The device of claim 24 wherein the processor is configured to identify a respiratory related arousal event based on the comparison.

28. The device of claim 24 wherein the sensor comprises a strain gauge, a piezoresistor, a tensometer or a spring guage.

29. The device of claim 28 wherein the sensor comprises a component of headgear.

30. The device of claim 29, wherein the sensor is configured to detect changes in tension of one or more straps of the headgear.

31. The device of claim 29 wherein the sensor is configured to detect changes in head or face contact compression with a portion of the headgear.

32. The device of claim 28 wherein the sensor comprises a component of headgear for a patient interface for a respiratory treatment apparatus, the patient interface comprising a breathable gas conduit.

33. The device of claim 28 wherein the sensor comprises a component of a patient interface for a respiratory treatment apparatus, the patient interface comprising a respiratory mask and a breathable gas conduit.

34. The device claim 24 wherein the processor is further configured to control a change to a respiratory treatment variable setting based on the analysis of the head strain signal.

35. The device of claim 34 wherein the respiratory treatment variable comprises pressure, wherein the processor is further configured to analyze data derived from an additional sensor, and wherein the control of the change to the respiratory treatment pressure setting is further based on the analysis by the processor of the data derived from the additional sensor.

36. The device of claim 35 wherein the additional sensor is a flow sensor.

37. The device of claim 23, wherein the processor is configured for analyzing the head strain signal by way of:

generating a first and a second filtered head strain signals based on the generated head strain signal;

making a comparison based on the first and the second filtered head strain signals, and

generating an indicator of a presence or absence of significant respiratory effort based on the comparison.

38. The device of claim 37, wherein the comparison includes comparing the second filtered head strain signal with a proportion of the first filtered head strain signal.

39. The device of claim 37 wherein the first filtered head strain signal comprises a long term average head strain signal, such as a long term absolute average, and the second filtered head strain signal comprises a short term average head strain signal.

40. The device of claim 37, wherein an obtained indication of significant head strain is used to classify an apnea or a hypopnea as an obstructive event.

41. The device of claim 37, wherein an obtained indication of an absence of a significant head strain is used to classify an apnea or a hypopnea as a central event.

42. The device of claim 37, wherein the first and second filtered head strain signals are derived from a plurality of head strain signals.

43. The device of claim 42, wherein each of the first and the second filtered head strain signals is derived from a combined head strain signal, such as a signal representing a sum of multiple head strain signals.

44. A respiratory treatment apparatus comprising:

a patient interface including a respiratory mask and headgear, the patient interface comprising one or more sensors configured to generate a head strain signal;

a flow generator adapted to be coupled to the patient interface and to generate a flow a breathable gas through the patient interface, and

a processor, coupled with the flow generator and adapted to couple with the one or more sensors, the processor configured to control the flow generator, and to control a detection of respiratory related effort by analysis of the head strain signal.

45. The apparatus of claim 44 wherein the analysis comprises a comparison of the head strain signal and a threshold.

46. The apparatus of claim 45 wherein the threshold is derived from a prior head strain signal measured with the one or more sensors.

47. The apparatus of claim 44 wherein the processor is configured to identify a type of a detected apnea or hypopnea as one of central, obstructive or mixed, based on the presence of respiratory effort.

48. The apparatus of claim 45 wherein the processor is also configured to identify a respiratory related arousal event based on the comparison.

49. The apparatus of claim 44 wherein at least one of the one or more sensors comprises a strain gauge, a piezoresistor, a tensometer or a spring guage.

50. The apparatus of claim 49 wherein at least one of the one or more sensors comprises a component of headgear.

51. The apparatus of claim 50, wherein the one or more sensors are configured to detect changes in tension of one or more straps of the headgear.

52. The apparatus of claim 50 wherein the one or more sensor are configured to detect changes in head or face contact compression with a portion of the headgear.

53. The apparatus of claim 49 wherein at least one of the one or more sensors comprises a component of a respiratory mask.

54. The apparatus of claim 44 wherein the processor is further configured to control a change to a respiratory treatment variable setting of the flow generator based on the analysis of the head strain signal.

55. The apparatus of claim 54 wherein the respiratory treatment variable comprises pressure, wherein the processor is further configured to analyze data derived from an additional sensor, and wherein the control of the change to the respiratory treatment pressure or ventilation setting is further based on the analysis by the processor of the data derived from the additional sensor.

56. The apparatus of claim 55 wherein the processor is further adapted to couple with a flow sensor, and wherein the additional sensor is the flow sensor.

57. The apparatus of claim 44, wherein the processor is configured for analyzing the head strain signal by way of:

generating a first and a second filtered head strain signals based on the generated head strain signal;

making a comparison based on the first and the second filtered head strain signals, and

generating an indicator of a presence or absence of significant respiratory effort based on the comparison.

58. A patient interface device for a respiratory treatment apparatus, the patient interface device comprising:

a respiratory mask and headgear supporting the mask;

one or more sensors configured to generate a head strain signal, the one or more sensors being adapted for coupling with a signal interface of a processor of a respiratory treatment apparatus for detection of respiratory related effort by analysis of the head strain signal,

wherein the patient interface device is configured to conduct a flow of breathable gas from a flow generator of the respiratory treatment apparatus.

59. The device of claim 58 wherein at least one of the one or more sensors comprises a strain gauge, a piezoresistor, a tensometer or a spring gauge.

60. The device of claim 59 wherein at least one of the one or more sensors comprises a component of the headgear.

61. The device of claim 60, wherein at least one of the one or more sensors is configured to detect changes in tension of the headgear.

62. The device of claim 59 wherein at least one of the one or more sensors is configured to detect changes in head, neck or face contact compression with a portion of the patient interface.

63. The device of claim 58 wherein at least one of the one or more sensors comprises a component of the mask.