Microprocessor system for the simplified diagnosis of sleep apnea

• US 20010018557A1
• Filed: 02/06/2001
• Published: 08/30/2001
• Est. Priority Date: 08/19/1992
• Status: Active Grant

• Current Assignee: Lawrence A. Lynn
• Original Assignee: Lawrence A. Lynn
• Inventors: Lynn, Eric N., Lynn, Lawrence A.
• Granted Patent: US 6,760,608 B2
• Time in Patent Office: Days
• 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 steps of:

a. monitoring a 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,

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 proceeds said second waveform variation.

8. The method of

claim 1

wherein said parameter is a respiratory parameter.

9. The method of

claim 1

wherein said parameter is an oximetry parameter.

10. The method of

claim 1

wherein said method includes using a microprocessor to perform at least steps b through d.

11. The method of

claim 1

wherein said method includes using a microprocessor to perform at least steps b through e.

12. The method of

claim 1

wherein said waveform is a waveform indicative of the flow of gas though at least one of a patients nose and mouth.

13. The method of claim S wherein said first waveform variation immediately proceeds said second waveform variation.

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

a. monitoring a 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,

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 the step of identifying at least a third waveform variation indicative of another 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 the step of 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 the step of 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 including steps of:

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,

c. determining the severity of sleep apnea 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 21

wherein each said apnea has an associated duration and further including the step of 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.

26. The method of

claim 25

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.

27. The method of

claim 26

wherein said duration result is the average duration of decreased oxygen saturation.

28. The method of

claim 25

wherein said duration result is the average apnea duration.

29. The method of

claim 24

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

30. The method of

claim 26

wherein said decrease in oxygen saturation defines a value of slope of decrease and further including the step of determining said value of slope and using said value of slope to determine the severity of apnea.

31. The method of

claim 30

wherein the value of slope is the average slope.

32. The method of

claim 30

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

33. The method of

claim 32

wherein the value of the initial portion slope is the average slope of the initial portion.

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

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

b. determining said spatial relationship,

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

36. The method of

claim 34

wherein said plurality of sequential apneas comprises a cluster of closely spaced apneas.

35. A method of determining the severity of sleep apnea comprising steps of:

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

b. determining said temporal relationship,

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

37. The method of

claim 35

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,

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.