ACOUSTIC DETECTION FOR RESPIRATORY TREATMENT APPARATUS

• US 20110313689A1
• Filed: 02/10/2010
• Published: 12/22/2011
• Est. Priority Date: 02/11/2009
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Martin, Dion Charles Chewe, Farrugia, Steven Paul, Holley, Liam
• Granted Patent: US 10,773,038 B2
• Time in Patent Office: Days
• US Class Current: 702/56
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• 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 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/14 Detection of the presence or absence of a tube, a connector or a container in an apparatus
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3365 Rotational speed
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 2230/46 : Resistance or compliance of the lungs

Abstract

Methods and apparatus provide acoustic detection for automated devices such as respiratory treatment apparatus. In some embodiments of the technology, acoustic analysis of noise or sound pulses, such as a cepstrum analysis, based on signals of a sound sensor (104) permits detection of obstruction (O) such as within a patient interface, mask or respiratory conduit (108) or within patient respiratory system. Some embodiments further permit detection of accessories such as an identification thereof or a condition of use thereof, such as a leak. Still further embodiments of the technology permit the detection of a patient or user who is intended to use the automated device.

Claims

1. A method for detecting a respiratory treatment conduit obstruction comprising:

determining with a sound sensor a measure of sound of a flow generator within a respiratory treatment conduit; and

analyzing the measure of sound from the sound sensor with a processor; and

indicating with the processor a presence or absence of obstruction in the respiratory treatment conduit based on the analyzing.

2. The method of claim 1 wherein the analyzing comprises calculating a Fourier transform from data samples representing the measure of sound.

3. The method of claim 2 wherein the analyzing further comprises calculating a logarithm of the transformed data samples representing the measure of sound.

4. The method of claim 3 wherein the analyzing further comprises calculating an inverse transform of the logarithm of the transformed data samples representing the measure of sound.

5. The method of claim 4 wherein the analyzing further comprises calculating a difference between (a) the inverse transform of the logarithm of the transformed data samples representing the measure of sound and (b) an inverse transform of a logarithm of Fourier transformed data samples representing a sound measured from an unobstructed version of the respiratory treatment conduit.

6. The method of claim 5 wherein the indicating comprises displaying a graph of data based on the difference calculating.

7. The method of claim 6 further comprising detecting a location and extent of the presence of obstruction based on data of the difference calculating.

8. The method of claim 7 wherein the extent is determined from an amplitude value of a significant sample of the data of the difference calculating.

9. The method of claim 8 wherein the location is determined from a position of the significant sample in the data of the difference calculating.

10. The method of claim 9 wherein the respiratory treatment conduit comprises an endotracheal tube.

11. The method of claim 10 wherein the flow generator generates the sound within the respiratory treatment conduit by changing the flow generator speed, then generated sound being flow generator noise.

12. The method of claim 1 further comprising pre-measuring sound from an unobstructed version of the respiratory treatment conduit.

13. The method of claim 1 wherein the sound sensor is a single microphone.

14. An apparatus for detecting a respiratory treatment conduit obstruction comprising:

a microphone adapted for coupling with a respiratory treatment conduit to generate a measure of sound of a flow generator within the respiratory treatment conduit; and

a processor configured to analyze data samples of the measure of sound from the microphone, the processor being further configured to indicate a presence or absence of obstruction in the respiratory treatment conduit based on the analyzed data samples.

15. The apparatus of claim 14 wherein the microphone is adapted with an endotracheal tube coupler, the endotracheal tube coupler comprising an opening to connect with a portion of an endotracheal tube.

16. The apparatus of claim 15 wherein the endotracheal tube coupler further comprises an opening adapted to connect with a portion of a ventilator supply tube.

17. The apparatus of claim 15 wherein the endotracheal tube coupler further comprises a microphone chamber adapted with a membrane to separate the chamber from a gas channel of the coupler.

18. The apparatus of claim 17 wherein the endotracheal tube coupler further comprises a vent adapted to permit the microphone chamber to equalize with ambient pressure.

19. The apparatus of claim 14 further comprising the flow generator, wherein the processor is further configured to control the flow generator to generate a respiratory treatment.

20. The apparatus of claim 14 wherein the processor is configured to calculate a Fourier transform from data samples representing the measure of sound.

21. The apparatus of claim 20 wherein the processor is configured to analyze the data samples by calculating a logarithm of the transformed data samples representing the measure of sound.

22. The apparatus of claim 21 wherein the processor is configured to analyze the data samples by further calculating an inverse transform of the logarithm of the transformed data samples representing the measure of sound.

23. The apparatus of claim 22 wherein the processor is configured to analyze the data samples by further calculating a difference between (a) the inverse transform of the logarithm of the transformed data samples representing the measure of sound and (b) an inverse transform of a logarithm of Fourier transformed data samples representing a measure of sound measured from an unobstructed version of respiratory treatment conduit.

24. The apparatus of claim 23 wherein the processor is configured to indicate the presence of obstruction by displaying a graph of data based on the difference calculating.

25. The apparatus of claim 24 further wherein the processor is configured to detect a location and extent of the presence of obstruction based on data of the difference calculating.

26. The apparatus of claim 25 wherein the extent is determined from an amplitude of a significant sample of the data of the difference calculating.

27. The apparatus of claim 26 wherein the location is determined from a position of the significant sample in the data of the difference calculating.

28. The apparatus of claim 14 wherein the processor is further configured to pre-measure sound from an unobstructed version of the respiratory treatment conduit.

29. The apparatus of claim 14 wherein the respiratory treatment conduit comprises an endotracheal tube.

30. The apparatus of claim 14 wherein the flow generator generates the sound within the respiratory treatment conduit by changing the speed of the flow generator, the sound being flow generator noise.

31. An apparatus for detecting a respiratory treatment conduit obstruction comprising:

a sound sensing means to generate a measure of sound of a flow generator within a respiratory treatment conduit;

a controller means, coupled with the sound sensing means, the controller means for controlling a determination of a presence of obstruction in the respiratory treatment conduit by analyzing the measure of sound from the sound sensing means.

32. The apparatus of claim 31 further comprising an endotracheal tube coupling means for housing the sound sensing means and for connecting with a portion of an endotracheal tube and a portion of a ventilator supply tube.

33. The apparatus of claim 32 wherein the coupling means further comprises a membrane to separate a ventilator gas channel and the sound sensing means.

34. The apparatus of claim 33 wherein the coupling means further comprises a venting means for equalizing the sound sensing means with ambient pressure.

35. The apparatus of claim 31 further comprising the flow generator, wherein the controller means is further adapted for controlling the flow generator to generate a respiratory treatment.

36. The apparatus of claim 31 further comprising a respiratory treatment conduit, and wherein the respiratory treatment conduit comprises an endotracheal tube.

37. The apparatus of claim 31 further comprising a sound means for generating a sound within the respiratory treatment conduit, the sound means comprising a servo-controlled blower.

38. The apparatus of claim 31 wherein the sound sensing means comprises a single microphone.

39. A method for detecting a respiratory system obstruction comprising:

determining with a sound sensor a measure of sound of a flow generator; and

analyzing the measure of sound from the sound sensor with a processor by calculation of a cepstrum from the measure of sound; and

indicating with the processor a presence or absence of obstruction in the respiratory system of a patient based on the analyzing.

40. The method of claim 39 further comprising detecting an extent of the presence of obstruction based on calculating a difference between the cepstrum from the measure of sound and a cepstrum determined from a prior measure of sound.

41. The method of claim 40 wherein the extent is determined from an amplitude value of a significant sample of the data of the difference calculating.

42. The method of claim 41 wherein a location is determined from a position of the significant sample in the data of the difference calculating, and wherein the position represents a point beyond a known end of a respiratory treatment conduit.

43. An apparatus for detecting a respiratory obstruction comprising:

a microphone adapted for coupling with a respiratory treatment conduit to generate a measure of sound of a flow generator; and

a processor configured to analyze data samples of the measure of sound from the microphone by calculation of a cepstrum with the data samples of the measure of sound, the processor being further configured to indicate a presence or absence of obstruction in the respiratory system of a patient based on the analyzed data samples.

44. The apparatus of claim 43 further comprising detecting an extent of the presence of obstruction based on calculating a difference between the cepstrum from the measure of sound and a cepstrum determined from a prior measure of sound.

45. The apparatus of claim 44 wherein the extent is determined from an amplitude value of a significant sample of the data of the difference calculating.

46. The apparatus of claim 45 wherein a location is determined from a position of the significant sample in the data of the difference calculating, and wherein the position represents a point beyond a known end of a respiratory treatment conduit.

47. The apparatus of claim 43 further comprising a flow generator, wherein the processor is further adapted for controlling the flow generator to generate a respiratory treatment.

48. A device for use with a flow generator that generates a supply of pressurized air to be provided at an outlet to a patient for treatment, wherein the device comprises:

a patient interface attachable to the outlet of the flow generator;

an emitter generating a first signal;

a sensor to receive the first signal and a second signal reflected from the patient interface; and

a controller that processes the first signal and reflected second signal, and wherein the controller detects the connection of a patient interface based on the processed reflected second signals.

49. The device of claim 48, wherein the first signal is either:

an acoustic impulse or a continuous acoustic signal.

50. The device of claim 49, wherein the sensor is microphone, pressure sensor, or flow sensor.

51. The device of claim 50, wherein the controller processes the first and second signals by cepstrum analysis.

52. The device of claim 51, wherein the emitter is the flow generator.

53. The device of claim 52, wherein the patient interface includes:

a mask and tubing.

54. The device of claim 53, wherein the sensor mounted or encapsulated in or proximal to outlet of flow generator.

55. The device of claim 54, wherein the sensor is:

a microphone;

pressure;

or flow sensor.

56. The device of claim 55, wherein the controller transfers information about the patient interface to a computer.

57. The device of claim 56, wherein the sensor is positioned proximal to the outlet of the flow generator.

58. The device of claim 48 wherein the detection of the connection of a patient interface comprises an identification of a particular mask model.

59. The device of claim 48 wherein the detection of the connection of a patient interface comprises a detection of a leak associated with the patient interface.

60. A device for use with a flow generator that generates a supply of pressurized air to be provided at an outlet to a patient for treatment, wherein the device comprises:

a patient interface attachable to the outlet of the flow generator;

an emitter generating a first signal;

a sensor to receive the first impulse and a second signal reflected from the patient interface; and

a controller that processes the first and reflected second signals,

and wherein the controller identifies the patient interface based on at least one feature of the reflected second signal being compared to at least one feature of set of predetermined acoustic signals.

61. A device for use with a flow generator that generates a supply of pressurized air to be provided at an outlet to a patient for treatment, wherein the device comprises:

a patient interface attachable to the outlet of the flow generator;

an emitter generating a first signal;

a sensor to receive the first and a second signal reflected from the patient interface; and

a controller that processes the impulse and reflected second signals,

and wherein the controller identifies a fault in the patient interface based on at least one feature of the reflected second signal being compared at least one feature of set of predetermined acoustic signals.

62. A method for identifying patient interfaces adapted to connect a flow generator, wherein generates a supply of pressurized air from an outlet, wherein the method comprises:

emitting an first signal in the airpath;

detecting the first signal and a second signal reflected along the airpath;

filtering signals to obtain the second signal;

comparing second signal to an array of predetermined reflected signals of patient interfaces; and

identifying a patient interface connected to the airpath based on a comparison of second signal to said array.

63. A method of identifying a type of mask connected to flow generator by characterizing the acoustic reflection of the mask.

64. A method for detecting or identifying characteristics in the airpath, wherein the method comprises:

emitting an first signal in the airpath;

detecting the first signal and a second signal reflected along the airpath;

filtering signals to obtain the second signal;

comparing second signal to an array of predetermined characteristics of airpaths; and

identifying characteristics in the airpath based on a comparison of second signal to said array.

65. The method of claim 64, wherein the airpath includes a patient interface

66. The method of claim 64, wherein the airpath includes the respiratory system of a patient.

67. The method of claim 64, wherein the characteristics include one or more selected from the following group:

restrictions in airpaths, airpath diameters, airpath lengths, and airpath occlusions.

68. The method of claim 64, wherein the method identifies characteristics of patient interface.

69. The method of claim 64, wherein the characteristics of patient interface are used to adjust a therapy parameter that controls setting of a flow generator.

70. An respiratory treatment apparatus comprising:

a microphone adapted for coupling with a respiratory treatment conduit to generate a measure of sound from the conduit, the sound being generated noise of a flow generator; and

a processor configured to analyze data samples of the measure of sound from the microphone by comparison of them with previously stored data samples representing a template, the processor being further configured to detect a system or patient characteristic from the comparison.

71. The apparatus of claim 70 wherein the analysis of data samples comprises a calculation of a cepstrum with the data samples of the measure of sound.

72. A method for authenticating a user of a device comprising:

determining with a sound sensor a measure of sound of a sound generator within a sound conduit directed to an anatomical cavity of a user of a device; and

analyzing the measure of sound from the sound sensor with a processor by calculation of a cepstrum from the measure of sound; and

determining with the processor that the user is a pre-authorized user based on the analyzing.

73. The method of claim 72 wherein the determining comprises permitting an operation of the device.

74. The method of claim 72 wherein the sound generator comprises a speaker and the sound sensor comprises a microphone.

75. The method of claim 72 wherein the device comprises a respiratory treatment apparatus, the sound generator comprises a flow generator and the sound conduit comprises a respiratory supply tube.

76. The method of claim 72 wherein the analyzing comprises comparing data of the cepstrum with data of a prior cepstrum determined with a prior measure of sound from a setup process.

77. The method of claim 76 further comprising determining the prior measure of sound taken in a setup process.

78. An apparatus for authenticating a user comprising:

a sound conduit adapted to direct an acoustic signal to an anatomical cavity of a user of the apparatus;

a sound generator to generate the acoustic signal;

a microphone adapted for coupling with the sound conduit to generate a measure of the acoustic signal; and

a processor configured to analyze data samples of the measure of the acoustic signal from the microphone by calculation of a cepstrum with the data samples of the measure of sound, the processor being further configured to determine that the user is a pre-authorized user based on the analysis.

79. The apparatus of claim 78 wherein the processor is configured to permit an operation of the apparatus based on the determination.

80. The apparatus of claim 79 wherein the sound generator comprises a speaker.

81. The apparatus of claim 78 wherein the analysis of the processor comprises comparing data of the cepstrum with data of a prior cepstrum determined from a prior measure of sound taken in a setup process.

82. The apparatus of claim 81 wherein the processor is further configured to set the prior measure in a setup process.

83. The apparatus of claim 78 wherein the apparatus comprises a respiratory treatment apparatus, the sound generator comprises a servo-controlled blower and the sound conduit comprises a respiratory supply tube and mask or nasal cannula.