Microprocessor system for the simplified diagnosis of sleep apnea

• US 6,223,064 B1
• Filed: 07/14/1998
• Issued: 04/24/2001
• Est. Priority Date: 08/19/1992
• Status: Expired due to Term

• Current Assignee: Lawrence A. Lynn
• Original Assignee: Lawrence A. Lynn
• Inventors: Lynn, Eric N., Lynn, Lawrence A.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US09/115,226
• Time in Patent Office: 1,015 Days
• Field of Search: 600/323, 600/324, 600/333, 600/483, 600/484, 600/529, 600/534, 600/537, 600/538, 600/595
• US Class Current: 600/324
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

A method of evaluating a patient with sleep apnea includes monitoring a patient to produce at least one timed waveform of at least one physiologic parameter, identifying along the waveform a first waveform variation indicative of an apnea, identifying along the waveform a second waveform variation indicative of another apnea, determining the interval intermediate at least one portion of the first waveform variation and at least one portion of the second waveform, and assessing the severity of sleep apnea based on at least the determining. A device for determining the severity of sleep apnea comprises a monitor capable of generating a signal indicative of at least one physiologic parameter and a processor capable of processing the signal, the processor operating to generate a timed waveform of the parameter and to identify a plurality of sequential waveform variations indicative of a corresponding plurality of sequential apneas, the sequential waveform variations having temporal and spatial relationships between the waveform variations and along the waveform, the processor further operating to determine at least one of the temporal and the spatial relationships and displaying the determining so that the determining can be used to assess the severity of sleep apnea.

Claims

1. A method of evaluating a patient with sleep apnea comprising:

a. monitoring the patient to produce at least one timed waveform of at least one physiologic parameter,

b. identifying along said waveform a first waveform variation indicative of an apnea,

c. identifying along said waveform a second waveform variation indicative of another apnea,

d. determining the interval intermediate at least one portion of said first waveform variation and at least one portion of said second waveform, and

e. assessing the severity of sleep apnea based on at least said determining.

2. The method of claim 1 wherein said interval is a value indicative of the sufficiency of recovery between said apnea and said another apnea.

3. The method of claim 1 wherein said one portion of the first waveform variation corresponds to said one portion of the second waveform variation.

4. The method of claim 3 wherein said one portion of the first waveform variation is substantially the last portion of said first waveform variation.

5. The method of claim 4 wherein said one portion of the second waveform variation is the substantially the first portion of the second waveform variation.

6. The method of claim 5 wherein said first waveform variation is adjacent said second waveform variation.

7. The method of claim 5 wherein said first waveform variation precedes said second waveform variation.

8. The method of claim 5 wherein said first waveform variation immediately precedes said second waveform variation.

9. The method of claim 1 wherein said parameter is a respiratory parameter.

10. The method of claim 1 wherein said parameter is an oximetry parameter.

11. The method of claim 1 wherein said method includes using a microprocessor to perform at least the processing of b through d.

12. The method of claim 1 wherein said method includes using a microprocessor to perform at least the processing of b through e.

13. The method of claim 1 wherein said waveform is a waveform indicative of the flow of gas though at least one of the patient'"'"'s nose and the patient'"'"'s mouth.

14. A method of evaluating a patient with sleep apnea comprising:

a. monitoring the patient to produce at least one timed waveform of at least one physiologic parameter,

b. identifying along said waveform a first waveform variation indicative of an apnea,

c. identifying along said waveform at least a second waveform variation indicative of another apnea, and

d. determining the severity of sleep apnea based at least on the position of said second waveform variation relative to at least said first waveform variation.

15. The method of claim 14 further including identifying at least a third waveform variation indicative of a third apnea and wherein said determining is based on at least the position of said third waveform variation relative to at least one of said first and second waveform variations.

16. The method of claim 14 further including identifying at least one cluster of waveform variations indicative of a corresponding cluster of apneas, and wherein said determining is based on the position of said waveform variations within said cluster relative to other waveform variations within said cluster.

17. The method of claim 14 further including identifying at least one cluster of waveform variations indicative of a corresponding cluster of apneas said cluster producing a spatial cluster waveform pattern indicative of a spatial pattern of a corresponding cluster of apneas and further determining the spatial relationships of said waveform variations within said cluster waveform pattern and using at least said determining to determine the severity of sleep apnea.

18. A device for determining the severity of sleep apnea comprising a monitor capable of generating a signal indicative of at least one physiologic parameter and a processor capable of processing said signal, said processor operating to generate a timed waveform of said parameter and to identify a plurality of sequential waveform variations indicative of a corresponding plurality of sequential apneas, said sequential waveform variations having temporal and spatial relationships between said waveform variations and along said waveform, said processor further operating to determine at least one of said temporal and said spatial relationships and displaying said determining so that said determining can be used to assess the severity of sleep apnea.

19. The device of claim 18 wherein said waveform variations occur in a sequential order with at least one interval intermediate said variations and wherein said determining comprises said processor measuring said at least one interval intermediate said variations.

20. The device of claim 19 wherein said plurality of sequential waveform variations is indicative of a number of sequential apneas equal to the number of said sequential waveform variations.

21. A method for determining the severity of sleep apnea in a patient, the method including:

a. identifying a plurality of sequential apneas, said apneas being separated by sequential intervening intervals,

b. determining a magnitude value of at least a portion of said intervening intervals, and

c. determining the severity of sleep apnea in the patient based on the magnitude value of at least a portion of said intervals.

22. The method of claim 21 wherein said intervening intervals are time intervals.

23. The method of claim 22 wherein said magnitude value is the average intervening time interval.

24. The method of claim 21 wherein said sequential apneas are separated by recovery intervals said intervening intervals comprising said recovery intervals.

25. The method of claim 24 wherein said recovery interval is associated with a value of arterial oxygen saturation during said recovery interval, the method further including determining said value of said oxygen saturation during said recovery interval and using said value to determine the severity of sleep apnea.

26. The method of claim 21 wherein each said apnea has an associated duration, the method further including measuring at least a portion of said associated duration to determine a duration result and further using at least said duration result to determine the severity of sleep apnea.

27. The method of claim 26 wherein said apnea induces a decrease in oxygen saturation and wherein said associated duration is the duration of decreased oxygen saturation associated with said apnea.

28. The method of claim 27 wherein said duration result is the average duration of decreased oxygen saturation.

29. The method of claim 27 wherein said decrease in oxygen saturation defines a value of slope of decrease, the method further including determining said value of slope and using said value of slope to determine the severity of apnea.

30. The method of claim 29 wherein the value of slope is the average slope.

31. The method of claim 29 wherein said slope includes an initial portion and a terminal portion, the method further including determining a value of the initial portion and using said value of said initial portion to determine the severity of sleep apnea.

32. The method of claim 31 wherein the value of the initial portion slope is the average slope of the initial portion.

33. The method of claim 26 wherein said duration result is the average apnea duration.

34. A method of determining the severity of sleep apnea comprising:

a. identifying a plurality of sequential apneas having a spatial relationship to each other,

b. determining said spatial relationship, and

c. defining the severity of sleep apnea based on at least said determining.

35. The method of claim 34 wherein said plurality of sequential apneas comprises a cluster of closely spaced apneas.

36. A method of determining the severity of sleep apnea comprising:

a. identifying a plurality of sequential apneas having a temporal relationship between each other,

b. determining said temporal relationship, and

c. defining the severity of sleep apnea based on at least said determining.

37. The method of claim 36 wherein said plurality of sequential apneas comprises a cluster of closely spaced apneas.

38. A method of defining the severity of sleep apnea comprising:

a. identifying a plurality of sequential apneas,

b. determining a value indicative of the sufficiency of the recovery between said apneas, and

c. defining the severity of sleep apnea based at least on said determining.

39. The method of claim 38 wherein said value is the time interval between said apneas.

40. The method of claim 38 wherein said value is the number of breaths between said apneas.

41. The method of claim 38 wherein said value is the quotient of said time interval and an indicator of the duration of at least one apnea adjacent said time interval.

42. The method of claim 41 wherein said indicator of the duration is the lowest oxygen saturation associated with said at least one apnea.

43. The method of claim 41 wherein said indicator of the duration is a measure of the time duration of said at least one apnea.

44. A microprocessor system for the evaluation of a patient, the system comprising:

monitor having at least one sensor for positioning adjacent said patient, and

a processor programmed to;

(a) produce at least one timed waveform based on at least one physiologic parameter of the patient;

(b) identify along said timed waveform a first waveform variation induced by at least one of a first apnea and a first hypopnea;

(c) identify along said timed waveform at least a second waveform variation induced by at least one of another apnea and another hypopnea; and

(d) determine a relationship between at least one portion of said first waveform variation to at least one portion of said second waveform.

45. A system as in claim 44 wherein the processor is further programmed to:

(e) output a result of said determining.

46. The system claim of claim 44 wherein said relationship is a spatial relationship.

47. The system claim of claim 44 wherein said relationship is a temporal relationship.

48. The system of claim 44 wherein said processor is further programmed to:

(e) determine an interval intermediate at least one portion of said first waveform variation and at least one portion of said second waveform; and

(g) output an indication of said determining.

49. The system of claim 48 wherein said one portion of the first waveform variation is the substantially the last portion of the first waveform variation, and said one portion of the second waveform variation is the substantially the first portion of the second waveform variation.

50. The system of claim 44 wherein said first waveform variation comprises a decreasing portion coupled to a increasing portion, said decreasing portion being induced by said first apnea, and said increasing portion being induced by recovery from said first apnea.

51. The system of claim 50 wherein said second waveform variation comprises a decreasing portion coupled to a increasing portion, said decreasing portion being induced by said another apnea, and said increasing portion being induced by recovery from said another apnea, and wherein said interval is defined by the interval intermediate of at least one point along said increasing portion of said first waveform and at least one point along said decreasing portion of said second waveform.

52. The system of claim 51 wherein said parameter is the oxygen saturation of arterial blood.

53. The system of claim 52 wherein said second portion of said first waveform variation is a rise in oxygen saturation and said first portion of said second waveform variation is a fall in oxygen saturation, said rise immediately proceeding said fall.

54. The system of claim 44 wherein said processor is further programmed to identify a plurality of sequential apneas.

55. The system of claim 44 wherein said parameter is a respiratory parameter.

56. The system of claim 44 wherein said waveform is a waveform indicative of the flow of gas though at least one of a patient'"'"'s nose and mouth.

57. A system as in claim 44 wherein the processor is further programmed to:

(a) provide an output based on said determining.

58. The system of claim 44 wherein said processor is further programmed to:

(e) determine an interval intermediate at least one portion of said first waveform variation and at least one portion of said second waveform; and

(f) provide an output based on said interval.

59. A microprocessor system for determining at least one of the presence of sleep apnea and the severity of sleep apnea, the system comprising a monitor having at least one sensor for positioning adjacent said patient and a processor programmed to:

(a) produce at least one timed waveform of at least one physiologic parameter of a patient;

(b) identify along said timed waveform a first waveform variation induced by an apnea;

(c) identify along said timed waveform at least a second waveform variation induced by another apnea; and

(d) determine at least one of the presence and severity of sleep apnea based at least on a position in at least one of time and space of said second waveform variation relative to at least said first waveform variation.

60. The system of claim 59 wherein the processor is further programmed to identify at least a third waveform variation induced by a third apnea and wherein said determining at least one of the presence and severity of sleep apnea is based on at least the position of said third waveform variation relative to at least one of said first and second waveform variations.

61. The system of claim 59 wherein the processor is further programmed to identify at least one cluster of waveform variations indicative of a corresponding cluster of apneas, and wherein said determining at least one of the presence and severity of sleep apnea is based on the positions of said waveform variations within said cluster relative to other waveform variations within said cluster.

62. The system of claim 59 wherein the processor is further programmed to:

(e) identify at least one cluster of waveform variations indicative of a corresponding cluster of apneas said cluster producing a spatial cluster waveform pattern indicative of a spatial pattern of a corresponding cluster of apneas;

(f) determine the spatial relationships of said waveform variations within said cluster waveform pattern; and

(g) based on at least said determined spatial relationships, determine at least one of one of the presence and the severity of sleep apnea.

63. A device for providing an output useful in assessing a patient, the device comprising:

(A ) a monitor capable of generating a signal indicative of at least one measured physiologic parameter; and

(B) a processor capable of processing said signal, said processor programmed to;

(a) generate a timed waveform of said parameter;

(b) identify a plurality of closely spaced waveform variations indicative of a corresponding plurality of closely spaced apneas, said closely spaced waveform variations having temporal and spatial relationships between said waveform variations and along said waveform;

(c) determine at least one of said temporal and said spatial relationships; and

(d) provide an output based on said determining.

64. The device of claim 63 wherein said parameter produces waveform variations which occur in a sequential order with at least one interval intermediate said variations and wherein said determining comprises measuring said at least one interval intermediate said variations.

65. The device of claim 63 wherein the total number of said waveform variations defining said plurality of said closely spaced waveform variations is equal to the total number of said closely spaced apneas.

66. A microprocessor system for the evaluation of a patient, the system comprising a processor programmed to:

(a) identify a plurality of sequential apneas, said apneas being separated by sequential intervening intervals;

(b) determine a magnitude value of at least a portion of said intervening intervals; and

(c) provide an output based on the magnitude value of at least a portion of said intervals.

67. The system of claim 66 wherein said intervening intervals are time intervals.

68. The system of claim 67 wherein said magnitude value is the average intervening time interval.

69. The system of claim 67 wherein said sequential apneas are separated by recovery intervals said intervening intervals comprising said recovery intervals.

70. The system of claim 69 wherein said recovery interval is associated with a value of arterial oxygen saturation during said recovery interval, said system further programmed to:

determine a value indicative of said arterial oxygen saturation during said recovery interval, and,

using said value, to determine the severity of sleep apnea.

71. The system of claim 67 wherein each said sequential apnea has an associated duration said processor further programmed to:

(d) determine said duration to determine a duration result of at least one of said sequential apneas and,

(e) using said duration result with said value of said intervening interval, to determine the severity of sleep apnea.

72. The system of claim 71 wherein said apnea induces a decrease in oxygen saturation and wherein said associated duration is the duration of decreased oxygen saturation associated with said apnea.

73. The system of claim 72 wherein said decrease in oxygen saturation defines a magnitude of decrease, and wherein said magnitude of decrease is compared to said magnitude value of said intervening interval to determine the severity of sleep apnea.

74. The system of claim 72 wherein said decrease in oxygen saturation defines a value of slope of decrease, the microprocessor further programmed to determine said value of slope and using said value of slope to determine the severity of apnea.

75. The system of claim 74 wherein the value of slope is the average slope.

76. The system of claim 74 wherein said value of slope includes an initial portion and a terminal portion, the microprocessor further programmed to:

determine a value of the initial portion, and,

using said value of said initial portion, to determine the severity of sleep apnea.

77. The system of claim 76 wherein the value of the initial portion slope is the average slope of the initial portion.

78. The system of claim 71 wherein said duration result is the average duration.

79. A microprocessor system for determining in a patient at least one of the presence and the severity of sleep apnea, the system comprising a processor programmed to:

(a) identify a plurality of closely spaced waveforms, defined by a corresponding plurality of closely spaced apneas, said waveforms having a spatial relationship to each other, said spatial relationship being defined by at least one waveform induced by at least one apnea occurring at one time and at least one other waveform induced by at least one other apnea occurring at another time;

(b) determine said spatial relationship; and

(c) provide an output based on said determined spatial relationship.

80. The system of claim 79 wherein said spatial relationship is defined by said waveforms being similar to each other to produce a plurality of closely spaced and similar waveforms.

81. The system of claim 79 wherein said closely spaced waveform occur within 120 seconds of each other.

82. The system of claim 79 wherein said spatial relationship is defined by said closely spaced waveforms occurring at regular intervals.

83. The system of claim 79 wherein said waveforms define clusters of substantially regular waveform cycles, said spatial relationship being defined by said clusters.

84. A microprocessor system for evaluation of a patient, the system comprising a processor programmed to:

(a) identify a plurality of sequential apneas having a temporal relationship to each other;

(b) determine said temporal relationship; and

(c) define the severity of sleep apnea in the patient based on at least said determined relationship.

85. The system of claim 84 wherein said plurality of sequential apneas comprises a cluster of closely spaced apneas.

86. A microprocessor system for determining the severity of sleep apnea in a patient, the processor programmed to:

(a) identify a plurality of sequential apneas;

(b) determine a value indicative of the sufficiency of the recovery between said apneas; and

(c) define the severity of sleep apnea in the patient based at least on said determined value.

87. The system of claim 86 wherein said value is the time interval between said apneas.

88. The system of claim 87 wherein said processor is further programmed to determine a second value indicative of the duration of at least one of said sequential apneas adjacent said time interval and wherein said value indicative of the sufficiency of the recovery between said apneas is a mathematical comparison of said time interval and said second value.

89. The system of claim 86 wherein said value is the number of breaths between said apneas.

90. A microprocessor system for the evaluation of a patient the system comprising a processor programmed to:

(a) produce at least one timed waveform based on at least one physiologic parameter of the patient;

(b) identify along said timed waveform a plurality of apneas; and

(c) determine a relationship between aspects of at least some of said plurality of apneas.

91. A system as claim 90 wherein the relationship is based on at least one of:

(a) a temporal relationship between at least some of said plurality of apneas; and

(b) a spatial relationship between at least some of said plurality of apneas; and

(c) a sufficiency of recovery between at least some of said plurality of apneas; and

(d) an interval between at least some of said plurality of apneas; and

(e) a magnitude value relationship between at least some of said plurality of apneas.

92. A system as in claim 90 wherein the processor is further programmed to provide an output based on said determining.

93. A system as in claim 92 wherein said output is a result of said determining.

94. A system as in claim 92 wherein said output is an indication of said determining.

95. The system of claim 92 wherein said output is a visual output.

96. The system of claim 92 wherein said output is at least one of a text output and a numerical output.

97. A system as in claim 90 wherein the processor is further programmed to determine at least one of the presence or severity of sleep apnea based on said determining.