System and method of detecting and processing physiological sounds

• US 20030120159A1
• Filed: 10/04/2002
• Published: 06/26/2003
• Est. Priority Date: 12/18/1996
• Status: Active Grant

• Current Assignee: AusculSciences, Inc.
• Original Assignee: SonoMedica, Inc.
• Inventors: Mohler, Sailor H.
• Granted Patent: US 7,416,531 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• 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 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

An apparatus, operation and method for measurement of systemic and/or pulmonic blood pressure. The present invention offers a passive non-invasive method and system that can be used where measurement of systemic pressure with a traditional blood pressure cuff is contraindicated. The present invention also affords a means for early diagnosis and opportunity for intervention in patients with no symptoms or signs of elevated pulmonary blood pressure that can be performed as part of a routine physical exam. The present invention accomplishes this non-invasive measurement through detection, identification and characterization of the second heart sound acoustic signature associated with heart valve closure. An apparatus for measuring systemic and/or pulmonic blood pressure in accordance with the present invention includes a sensor assembly comprising a housing, an electronic module, a shock dampener, a mounting means, a transducer, an acoustic coupling and a back cover. The sensor assembly is connected to a data acquisition module which in turn is connected to a signal processing means, a remote connection means and a monitor. An improved acoustic coupling is disclosed that provides low-loss acoustic transmission coupling between the skin of the patient and the detector.

Claims

1. An apparatus for monitoring blood pressure comprising:

a means for detecting audio signals;

a means for signal processing connected to the signal detecting means;

a means for signal storage connected to the signal processing means; and

a means for monitoring, connected to the signal processing means.

2. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the audio signal detecting means is a sensor assembly.

3. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the audio signal detecting means is a plurality of sensor assemblies.

4. An apparatus for monitoring blood pressure as claimed in claim 2, wherein the sensor assembly comprises:

a housing having a front and a back;

an electronic module connected to the housing;

a shock dampener connected to the front of the housing;

a means for mounting connected to the housing;

a transducer connected to the mounting means;

an acoustic coupling connected to the transducer; and

a cover connected to the back of the housing.

5. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the housing further comprises a sound deadening material.

6. An apparatus for monitoring blood pressure as claimed in claim 5, wherein the housing further comprises nickel plated aluminum.

7. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the housing further comprises:

a rim having an inside and an outside, located on the periphery of the front of the housing;

a first indentation having an inside and an outside, that runs parallel and adjacent to the inside of the rim;

a second indentation that runs parallel and adjacent to the inside of the first indentation; and

a bore that is approximately centrally located within the second indentation.

8. An apparatus for monitoring blood pressure as claimed in claim 7, wherein the electronic module nests within the bore.

9. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the shock dampener is an “

O”

ring.

10. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the mounting means is a plastic mounting ring.

11. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the transducer is a piezoelement.

12. An apparatus for monitoring blood pressure as claimed in claim 4, wherein the acoustic coupling is a parametric acoustic transconductor.

13. An apparatus for monitoring blood pressure as claimed in claim 12, wherein the parametric acoustic transconductor comprises latex foam.

14. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the signal processing means is a computer with a central processing unit.

15. An apparatus for monitoring blood pressure as claimed in claim 14, wherein the computer with a central processing unit is an IBM compatible personal computer.

16. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the means for signal storage further comprises an array of disks.

17. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the means for signal storage further comprises an internal hard disk drive.

18. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the means for signal storage flirter comprises an internal hard disk drive.

19. An apparatus for monitoring blood pressure as claimed in claim 1, farther comprising:

a means for hard copy reproduction connected to the signal processing means.

20. An apparatus for monitoring blood pressure as claimed in claim 19, wherein the means for hard copy reproduction further comprises a printer.

21. An apparatus for monitoring blood pressure as claimed in claim 1, further comprising:

a means for remote connection connected to the signal processing means.

22. An apparatus for monitoring blood pressure as claimed in claim 21, wherein the means for remote connection further comprises a modem.

23. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the means for monitoring further comprises a high resolution EGA color display monitor.

24. An apparatus for monitoring blood pressure as claimed in claim 1, wherein the means for monitoring further comprises a high resolution VGA color display monitor.

25. An apparatus for monitoring blood pressure as claimed in claim 1, further comprising:

a means for data acquisition connected to the signal detection means and the signal processing means.

26. An apparatus for monitoring blood pressure as claimed in claim 25, wherein the means for data acquisition comprises an amplifier.

27. An apparatus for monitoring blood pressure as claimed in claim 26, wherein the amplifier comprises a tailored bandpass amplifier.

28. An apparatus for monitoring blood pressure as claimed in claim 27, wherein the tailored bandpass amplifier comprises a low frequency response from a predetermined first point to a predetermined second point, and a higher frequency response of a predetermined level, from the predetermined second point to a predetermined third point.

29. An apparatus for monitoring blood pressure as claimed in claim 28, wherein the predetermined level is about 20 dB.

30. An apparatus for monitoring blood pressure as claimed in claim 28, wherein the predetermined first point is about 100 Hz, the predetermined second point is about 100 Hz and the predetermined third point is about 600 Hz.

31. An apparatus for monitoring blood pressure as claimed in claim 28, where in the predetermined second point is about 60 Hz.

32. A method of determining blood pressure comprising:

performing initialization procedures;

acquiring physiologic signals;

acquiring background signals;

subtracting background signals from physiologic signals creating physiologic data;

processing physiologic data forming a time domain output and a frequency domain data output;

comparing the time domain output and the frequency domain output with a reference pattern and feature library; and

determining if a disease modality is indicated.

33. A method of determining blood pressure as claimed in claim 32, wherein

performing initialization further comprises:

initializing system;

calibrating system;

selecting sensors;

inputting patient parameters; and

clearing buffers.

34. A method of determining blood pressure as claimed in claim 32, wherein acquiring physiologic signals comprises acquiring acoustic signals.

35. A method of determining blood pressure as claimed in claim 32, wherein acquiring physiologic signals comprises acquiring electric signals.

36. A method of determining blood pressure as claimed in claim 32, wherein the physiologic signals are in an analog form, further comprising:

converting, the physiologic signals from the analog form to a digital form.

37. A method of determining blood pressure as claimed in claim 32, wherein the background signals are in an analog form, further comprising the step:

converting the background signals from the analog form to a digital form.

38. A method of determining blood pressure as claimed in claim 32, wherein processing further comprises:

applying signal conditioning and time domain averaging to the physiologic data forming conditioned and averaged data;

formatting the conditioned and averaged data in an array creating formatted data;

aligning and normalizing formatted data, creating aligned and formalized data;

normalizing and integrating the aligned and formalized data, creating normalized and integrated data, wherein said normalized and integrated data has time domain components and frequency domain components;

passing the time domain components of the normalized and integrated data through a time domain correlator and feature extraction process; and

passing the frequency domain components of the normalized and integrated data through a frequency domain correlator and feature extractor, creating the time domain output and the frequency domain output.

39. A method of determining blood pressure as claimed in claim 38, further comprising:

displaying the formatted data on a monitor.

40. A method of determining blood pressure as claimed in claim 38, further comprising:

displaying the aligned and normalized data on a monitor.

41. A method of determining blood pressure as claimed in claim 38, firer comprising:

displaying the normalized and integrated data on a monitor.

42. A method of determining blood pressure as claimed in claim 32, further comprising:

updating the reference pattern and feature library.

43. A method of determining systemic blood pressure using sonospectrography analysis comprising:

monitoring the frequency of a sound emitted by the aortic semilunar valve, wherein the sound is detected using a sensor assembly, to monitor physiologic signals, the sensor assembly comprising;

a housing having a front and a back;

an electronic module connected to the housing;

a shock dampener connected to the front of the housing;

a means for mounting connected to the housing;

an acoustic coupler connected to the mounting means;

a transducer connected to the acoustic coupler; and

a cover connected to the back of the housing;

processing the physiologic signals, the processing comprising;

applying signal conditioning and time domain averaging to the physiologic signals to form conditioned and averaged data;

formatting the conditioned and averaged data in an array to create formatted data;

aligning and normalizing formatted data, to create aligned and formalized data;

normalizing and integrating the aligned and formalized data, to create normalized and integrated data that has time domain components and frequency domain components;

passing the time domain components of the normalized and integrated data through a time domain correlator and feature extraction process;

passing the frequency domain components of the normalized and integrated data through a frequency domain correlator and feature extractor, to create a time domain output and a frequency domain output;

comparing time domain output and the frequency domain output with a reference pattern and feature library; and

determining if a disease modality is indicated.

44. A method of determining systemic blood pressure using sonospectrography analysis as claimed in claim 43, further comprising:

acquiring background signals; and

subtracting background signals from physiologic signals.

45. A sensor assembly for detecting physiological sounds comprising:

a housing having a front and a back;

an electronic module connected to the housing;

a shock dampener connected to the front of the housing;

a means for mounting connected to the shock dampener;

an acoustic coupler connected to the mounting means;

a transducer connected to the acoustic coupler; and

a cover connected to the back of the housing.

46. A sensor assembly as claimed in claim 45, wherein the housing further comprises a sound deadening material.

47. A sensor assembly as claimed in claim 46, wherein the housing further comprises nickel plated aluminum.

48. A sensor assembly as claimed in claim 45, wherein the housing further comprises:

a rim having an inside and an outside, that is located on the periphery of the front of the housing;

a first indentation having an inside and an outside, that runs parallel and adjacent to the inside of the rim;

a second indentation that runs parallel and adjacent to the inside of the first indentation; and

a bore, that is approximately centrally located within the second indentation.

49. A sensor assembly as claimed in claim 48, wherein the electronic module nests within the bore.

50. A sensor assembly as claimed in claim 45, wherein the shock dampener is an “

O”

ring.

51. A sensor assembly as claimed in claim 45, wherein the mounting means is a plastic mounting ring.

52. A sensor assembly as claimed in claim 45, wherein the transducer is a piezoelement.

53. A sensor assembly as claimed in claim 52, wherein the acoustic coupling is a parametric acoustic transconductor.

54. A sensor assembly as claimed in claim 53, wherein the parametric acoustic transconductor comprises latex foam.

55. A sensor assembly for detecting physiological sounds comprising:

a housing, having a front, a back, and an interior;

an electronic module that nests in the interior of the housing;

a first shock dampener connected to the front of the housing;

a first mounting means connected to the first shock dampener;

a transducer connected to the first mounting means;

a first acoustic coupling connected to the transducer;

a second shock dampener connected to the back of the housing;

a second mounting means connected to the second shock dampener;

a second transducer connected to the second mounting means; and

a second acoustic coupling connected to the second transducer.

56. A sensor assembly as claimed in claim 55, wherein the housing further comprises a sound deadening material.

57. A sensor assembly as claimed in claim 56, wherein the housing further comprises nickel plated aluminum.

58. A sensor assembly as claimed in claim 55, wherein the housing further comprises:

a first rim having an inside and an outside, that is located on the periphery of the front of the housing;

a first indentation having an inside and an outside, that runs parallel and adjacent to the inside of the first rim;

a second indentation that runs parallel and adjacent to the inside of the first indentation;

a bore, that is approximately centrally located within the second indentation;

a second rim having an inside and an outside, that is located on the periphery of the back of the housing;

a third indentation having an inside and an outside, that runs parallel and adjacent to the inside of the second rim; and

a fourth indentation, that runs parallel and adjacent to the inside of the third indentation.

59. A sensor assembly as claimed in claim 58, wherein the electronic module nests within the bore.

60. A sensor assembly as claimed in claim 58, wherein the first shock dampener is an “

O”

ring and the second shock dampener is an “

O”

ring.

61. A sensor assembly as claimed in claim 58, wherein the first mounting means is a plastic mounting ring and the second mounting means is a plastic mounting ring.

62. A sensor assembly as claimed in claim 58, wherein the first transducer is a piezoelement and the second transducer is a piezoelement.

63. A sensor assembly as claimed in claim 58, wherein the first acoustic coupling is a parametric acoustic transconductor and the second acoustic coupling is a parametric acoustic transconductor.

64. A sensor assembly as claimed in claim 58, wherein the parametric acoustic transconductor comprises latex foam.

65. An apparatus for determining blood pressure comprising:

an acoustic coupling, wherein the acoustic coupling provides a low-loss acoustic transmission coupling between skin and a piezoelectric transducer.

66. An apparatus for determining blood pressure as claimed in claim 65, wherein the acoustic coupling is a parametric acoustic transconductor.

67. An apparatus for determining blood pressure as claimed in claim 65, wherein the acoustic coupling has a high conduction coefficient.

68. An apparatus for determining blood pressure as claimed in claim 65 wherein the acoustic coupling comprises latex foam.

69. An apparatus for monitoring blood pressure comprising:

an acoustic coupling;

a transducer connected to the acoustic coupling;

an electronic module connected to the transducer;

a data acquisition module connected to the electronic module; and

a data cable connected to the electronic module and the data acquisition module.

70. An apparatus for monitoring blood pressure as claimed in claim 69, wherein the data cable is a twisted shielded pair.

71. A method of detecting and processing physiological sounds, comprising:

sensing physiological sounds to acquire analog physiological signals, the acquired analog physiological signals corresponding to basic heart sounds and sounds of interest; and

amplifying a predetermined frequency range of the acquired analog physiological signals that encompasses the sounds of interest, at least a portion of the predetermined frequency range being higher than another frequency range of the acquired analog physiological signals that encompasses the basic heart sounds.

72. The method of claim 71, further comprising:

sampling the amplified physiological signals that encompasses the sounds of interest; and

converting the sampled signals to digital signals.

73. The method of claim 72, further comprising:

displaying the digital signals.

74. The method of claim 72, further comprising:

subjecting the digital signals to a Fourier transformation.

75. The method of claim 74, further comprising:

displaying a time component and a frequency component of the digital signals subjected to the Fourier transformation.

76. The method of claim 72, said sampling being at a sampling rate between 4-48 KHz.

77. The method of claim 72, further comprising:

determining whether features contained within the digital signals match a known disease modality.

78. The method of claim 71, said amplifying being completed with a band-pass amplifier.

79. The method of claim 71, further comprising:

filtering the amplified physiological signals.

80. An assembly for detecting and processing physiological heart sounds, comprising:

a sensor for sensing physiological heart sounds so as to acquire analog physiological signals;

an amplifier configured to amplify a first frequency range of said physiological signals to a first level and configured to amplify a second frequency range of said physiological signals to a second level, said second level being higher than said first level, said first frequency range of physiological signals including frequencies that correspond to basic heart sounds, said second frequency range of said physiological signals including frequencies that correspond to sounds of interest, the sounds of interest having frequencies that are higher than frequencies of the basic heart sounds; and

an analog to digital converter configured to sample said amplified physiological signals in at least said second frequency range and convert said sampled signals to digital signals.

81. The assembly of claim 80, further comprising:

a display for displaying said digital signals.

82. The assembly of claim 80, said analog to digital converter having a sampling rate between 4-48 KHz.

83. The assembly of claim 80, said amplifier being configured such that said first frequency range of amplified signals has a lower end of approximately 10 Hz.

84. The assembly of claim 80, said amplifier being configured such that said second frequency range of amplified signals has a lower end of approximately 100 Hz.

85. The assembly of claim 80, said amplifier being configured such that said second level is approximately 20 dB higher than said first level.

86. The assembly of claim 80, said amplifier being configured such that said first range and said second range have a crossover point of approximately 100 Hz.

87. The assembly of claim 80, said amplifier including a band-pass amplifier.

88. The assembly of claim 80, further comprising:

a filter for filtering said amplified physiological signals in said first frequency range and said second frequency range.

89. A method of detecting and processing physiological sounds, the method comprising:

sensing the physiological sounds to acquire analog physiological signals, the sensed physiological sounds including basic heart sounds and sounds of interest;

amplifying a first frequency range of the physiological signals to a first level;

amplifying a second frequency range of the physiological signals to a second level that is higher than the first level, the second frequency range including frequencies that are higher than frequencies in the first frequency range, the second frequency range including frequencies of the sounds of interest;

sampling the amplified physiological signals in at least the second range; and

converting the sampled signals to digital signals.

90. The method of claim 89, further comprising:

displaying the digital signals.

91. The method of claim 89, further comprising:

subjecting the digital signals to a Fourier transformation.

92. The method of claim 91, further comprising:

displaying a time component and a frequency component of the digital signals subjected to the fourier transformation.

93. The method of claim 89, said sampling being at a sampling rate between 4-48 KHz.

94. The method of claim 89, a lower end of the first frequency range being approximately 10 Hz.

95. The method of claim 89, a lower end of the second frequency range being approximately 100 Hz.

96. The method of claim 89, the second level being approximately 20 dB higher than the first level.

97. The method of claim 89, further comprising:

determining whether features contained within the digital signals match a known disease modality.

98. The method of claim 89, the first frequency range and the second frequency range having a crossover point of approximately 100 Hz.

99. The method of claim 89, said amplifying of the first frequency range and the second frequency range being completed with a band-pass amplifier.

100. The method of claim 89, further comprising:

filtering the amplified physiological signals in the first range and the second range.