Method and apparatus for detecting respiratory effort

• US 10,448,893 B2
• Filed: 01/18/2012
• Issued: 10/22/2019
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Inventors: Armitstead, Jeffrey Peter, Richards, Glenn, Wells, Alicia Kristianne
• Primary Examiner(s): Berhanu, Etsub D
• Assistant Examiner(s): Catina, Michael
• Application Number:
  US13/352,758
• Publication Number:
  US 20120190998A1
• Time in Patent Office: 2,834 Days
• Field of Search: 600529, 600534
• 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:

using a sensor to generate a strain signal, the strain signal including one or both of a mouth strain signal and a jaw strain signal, the sensor being configured with a respiratory mask or headgear of a respiratory treatment apparatus to sense mask force or headgear tension, the headgear tension concerning change in tension of a strap of the headgear, wherein the sensor is configured to generate the strain signal in response to movement of one or both of a user'"'"'s mouth and jaw;

receiving the strain signal and a flow signal from a flow sensor in a processor, and

detecting breathing related events in the processor with the flow signal and strain signal, the detecting comprising analyzing the strain signal in the processor to detect respiratory related effort,

wherein the analyzing comprises a comparison of the strain signal and a threshold value;

and automatically controlling a change to a respiratory treatment variable in a controller of the respiratory treatment apparatus, based on the analyzing of the strain signal and the flow signal.

2. The method of claim 1 wherein the threshold is derived from a prior mouth strain signal or jaw strain signal measured with the sensor.

3. The method of claim 1 wherein the method further comprises indicating, with the processor, a type of detected apnea or hypopnea based on the analyzing of the strain signal, wherein the type of detected apnea or hypopnea is identified as one of central, obstructive or mixed, depending on a presence of respiratory effort.

4. The method of claim 1 further comprising identifying, with the processor, a respiratory related arousal event based on the comparison.

5. The method of claim 1 wherein the sensor comprises a strain gauge, a piezoresistor, a tensometer or a spring gauge.

6. The method of claim 5 wherein the sensor is a component of headgear.

7. The method of claim 6, wherein the sensor is configured to detect changes in tension of one or more straps of the headgear.

8. The method of claim 6 wherein the sensor is configured to detect changes in head or face contact compression with a portion of the headgear.

9. The method of claim 5 wherein the sensor is 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.

10. The method of claim 5 wherein the sensor is a component of a patient interface for a respiratory treatment apparatus, the patient interface comprising a respiratory mask and a breathable gas conduit.

11. The method of claim 1 wherein the respiratory treatment variable comprises pressure.

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

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

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

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

13. The method of claim 12, wherein the comparison includes comparing the second filtered strain signal with a proportion of the first filtered strain signal.

14. The method of claim 13, wherein the first filtered strain signal comprises a first average strain signal determined over a first period of time, and the second filtered strain signal comprises a second average strain signal determined over a second period of time, wherein the first period of time is longer than the second period of time.

15. The method of claim 12, wherein an obtained indication of strain of one or both of the user'"'"'s mouth and jaw is used to classify an apnea or a hypopnea as an obstructive event.

16. The method of claim 12, wherein an obtained indication of an absence of strain of one or both of the user'"'"'s mouth and jaw is used to classify an apnea or a hypopnea as a central event.

17. The method of claim 12, wherein the first and second filtered strain signals are derived from a plurality of strain signals.

18. The method of claim 16, wherein each of the first and the second filtered strain signals is derived from a combined strain signal representing a sum of multiple strain signals.

54. The method of claim 1 wherein the sensor is configured with a respiratory mask of a respiratory treatment apparatus to sense mask force.

55. The method of claim 1 wherein the sensor is configured with headgear of a respiratory treatment apparatus to sense headgear tension.

62. The method of claim 1, further comprising determining, with the processor, a type of detected apnea or hypopnea, based on the analyzing of the strain signal.

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

one or more sensors configured with a respiratory mask or headgear to generate a strain signal, the strain signal including one or both of a mouth strain signal and a jaw strain signal, the one or more sensors configured to sense mask force or headgear tension, the headgear tension concerning change in tension of a strap of the headgear, wherein the sensor is configured to generate the strain signal in response to movement of one or both of a user'"'"'s mouth and jaw;

a flow sensor configured to generate a flow signal, and

a processor, coupled with the one or more sensors and the flow sensor, the processor configured to control detection of breathing events with the flow signal and the strain signal, the detection comprising detection of respiratory related effort by analysis of the strain signal,

wherein the analysis comprises a comparison of the strain signal and a threshold value; and

wherein the processor is configured to automatically control a change to a respiratory treatment variable setting based on the analysis of the strain signal and the flow signal.

20. The device of claim 19 wherein the threshold is derived from a prior mouth strain signal or jaw strain signal measured with the strain sensor.

21. The device of claim 19 wherein the processor is configured to identify a type of detected apnea or hypopnea, based on the analyzing of the strain signal, as one of central, obstructive or mixed, depending on the presence of respiratory effort.

22. The device of claim 19 wherein the processor is configured to identify a respiratory related arousal event based on the comparison.

23. The device of claim 19, wherein the strain sensor comprises a strain gauge, a piezoresistor, a tensometer or a spring gauge.

24. The device of claim 23 wherein the sensor is a component of headgear.

25. The device of claim 24, wherein the strain sensor is configured to detect changes in tension of one or more straps of the headgear.

26. The device of claim 24 wherein the strain sensor is configured to detect changes in head or face contact compression with a portion of the headgear.

27. The device of claim 23 wherein the strain sensor comprises a component of headgear for a patient interface for a respiratory treatment apparatus, the patient interface comprising a breathable gas conduit.

28. The device of claim 23 wherein the strain 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.

29. The device of claim 19 wherein the respiratory treatment variable comprises pressure.

30. The device of claim 19, wherein the processor is configured for analyzing the strain signal by way of:

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

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

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

31. The device of claim 30, wherein the comparison includes comparing the second filtered strain signal with a proportion of the first filtered strain signal.

32. The device of claim 30 wherein the first filtered strain signal comprises a first average strain signal over a first period of time and the second filtered strain signal comprises a second average strain signal determined over a second period of time, wherein the first period of time is longer than the second period of time.

33. The device of claim 30, wherein an obtained indication of a strain of one or both of the user'"'"'s mouth and jaw is used to classify an apnea or a hypopnea as an obstructive event.

34. The device of claim 30, wherein an obtained indication of an absence of a strain of one or both of the user'"'"'s mouth and jaw is used to classify an apnea or a hypopnea as a central event.

35. The device of claim 30, wherein the first and second filtered strain signals are derived from a plurality of strain signals.

36. The device of claim 35, wherein each of the first and the second filtered strain signals is derived from a combined strain signal representing a sum of multiple strain signals.

56. The device of claim 19 wherein the one or more sensors are configured with a respiratory mask of a respiratory treatment apparatus to sense mask force.

57. The device of claim 19 wherein the one or more sensors are configured with headgear of a respiratory treatment apparatus to sense headgear tension.

37. A respiratory treatment apparatus comprising:

a patient interface including a respiratory mask and headgear, the patient interface comprising one or more sensors configured with the patient interface or the headgear to generate a strain signal, the strain signal including one or both of a mouth strain signal and a jaw strain signal, the one or more sensors configured to sense mask force or headgear tension, the headgear tension concerning change in tension of a strap of the headgear, wherein the sensor is configured to generate the strain signal in response to movement of one or both of a user'"'"'s mouth and jaw;

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

a flow sensor to generate a flow signal; and

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

wherein the analysis comprises a comparison of the strain signal and a threshold value; and

wherein the processor is configured to automatically control a change to a respiratory treatment variable setting of the flow generator based on the analysis of the strain signal and the flow signal.

38. The apparatus of claim 37 wherein the threshold is derived from a prior mouth strain signal or jaw strain signal measured with the one or more sensors.

39. The apparatus of claim 37 wherein the processor is configured to identify a type of a detected apnea or hypopnea, based on the analyzing of the strain signal, as one of central, obstructive or mixed, based on the presence of respiratory effort.

40. The apparatus of claim 37 wherein the processor is also configured to identify a respiratory related arousal event based on the comparison.

41. The apparatus of claim 37 wherein at least one of the one or more sensors comprises a strain gauge, a piezoresistor, a tensometer or a spring gauge.

42. The apparatus of claim 41 wherein at least one of the one or more sensors comprises a component of headgear.

43. The apparatus of claim 42, wherein the one or more sensors are configured to detect changes in tension of one or more straps of the headgear.

44. The apparatus of claim 42 wherein the one or more sensor are configured to detect changes in head or face contact compression with a portion of the headgear.

45. The apparatus of claim 41 wherein at least one of the one or more sensors is a component of a respiratory mask.

46. The apparatus of claim 37 wherein the respiratory treatment variable comprises pressure.

47. The apparatus of claim 37, wherein the processor is configured for analyzing the strain signal by way of:

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

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

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

58. The respiratory treatment apparatus of claim 37 wherein the one or more sensors are configured with a respiratory mask of a respiratory treatment apparatus to sense mask force.

59. The respiratory treatment apparatus of claim 37 wherein the one or more sensors are configured with headgear of a respiratory treatment apparatus to sense headgear tension.

48. 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 with the respiratory mask or the headgear to generate a strain signal, the strain signal including one or both of a mouth strain signal and a jaw strain signal, the one or more sensors configured to sense mask force or headgear tension, the headgear tension concerning change in tension of a strap of the headgear, wherein one or more sensors is configured to generate the strain signal in response to movement of one or both of a user'"'"'s mouth and jaw, the one or more sensors being adapted for coupling with a signal interface of a processor of a respiratory treatment apparatus for detection of breathing events with a flow signal of a flow sensor and the strain signal, the detection comprising detection of respiratory related effort by analysis of the strain signal and a threshold value,

wherein a change to a respiratory treatment variable setting is based on the analysis of the strain signal and the flow signal, and wherein the patient interface device is configured to conduct a flow of breathable gas from a flow generator of the respiratory treatment apparatus.

49. The device of claim 48 wherein at least one of the one or more sensors comprises a strain gauge, a piezoresistor, a tensometer or a spring gauge.

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

51. The device of claim 50, wherein at least one of the one or more sensors is configured to detect changes in tension of the headgear.

52. The device of claim 49 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.

53. The device of claim 48 wherein at least one of the one or more sensors is a component of the mask.

60. The patient interface device of claim 48 wherein the one or more sensors are configured with headgear of a respiratory treatment apparatus to sense headgear tension.

61. The patient interface device of claim 48 wherein the one or more sensors are configured with a respiratory mask of a respiratory treatment apparatus to sense mask force.