Sleep apnea detector system

• US 6,062,216 A
• Filed: 12/27/1996
• Issued: 05/16/2000
• Est. Priority Date: 12/27/1996
• Status: Expired due to Term

• Current Assignee: Engineered Vigilance, LLC
• Original Assignee: Children's Medical Center Corporation
• Inventors: Corn, Stephen B.
• Primary Examiner(s): Weiss, John G.
• Assistant Examiner(s): SRIVASTAVA, VIRENDRA KUMAR
• Application Number:
  US08/773,577
• Time in Patent Office: 1,236 Days
• Field of Search: 128/204.23, 128/204.21, 128/204.18, 600/529, 600/532, 600/534, 600/535, 600/538, 600/653.1, 600/453, 600/438, 600/552, 600/575
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16

Abstract

An apnea monitor and system for treatment includes a detector in a fixed console that projects a detection beam at a sleep surface. The detection beam is reflected off a patient on the surface and return light is analyzed to develop a signal which varies with external motion of the patient'"'"'s upper body. The motion signals are then fed to a pattern recognizer which identifies breath signals and analyzes them to detect cessation or excessive pauses in breathing, and trigger an alarm or intervention to restore breathing regularity. The monitor includes a laser for generating radiation. The radiation is reflected from the patient and is directed onto a detector. The detector produces output signals corresponding to the impinging reflected light, which are processed by a control element to determine the change of movement, e.g., the breathing rate, of the patient.

Claims

1. An apnea monitor for monitoring breathing of a subject, said monitor comprising

illumination means for producing radiation within a selected wavelength range,

projection means for projecting the radiation towards the subject,

motion determination means for non-invasively determining a change in position of an area of the subject on the basis of changes in radiation reflected by a surface that moves as a result of the subject'"'"'s breathing, and

breathing rate determination means for determining the breathing rate of the subject in response to the change in position of the subject.

2. The apnea monitor of claim 1, wherein the motion determination means comprises

a detector for detecting laser-generated radiation reflected from the subject, the detector producing electrical output signals in response to the reflected radiation incident thereupon, and

a processor in circuit with the detector for processing the electrical output signals to determine the change of position of the subject.

3. The apnea monitor of claim 1, wherein the illumination means emits laser radiation along a first axis, said monitor further comprising an optical network optically coupled to the laser and having a first optical element for directing a portion of the laser radiation to the motion determination means to form a reference beam.

4. The apnea monitor of claim 3, wherein the motion determination means comprises

a detector positioned to receive the reference beam and for detecting the laser-generated radiation reflected from the subject, the detector including means for combining the reflected radiation and the reference beam, and means for generating an electrical signal representative of a beat frequency corresponding to the Doppler shift between the reference beam and the radiation reflected from the subject, and

a processor in circuit with the detector for correlating said beat frequency to apnea of the subject.

5. The apnea monitor of claim 4, wherein the processor includes

means for counting extrema in the electrical signal generated by the detector, corresponding to interference fringes resulting from the reference beam and the reflected radiation, and

means for generating a signal indicative of changes in position of the subject, the processor determining apnea from lapses in said changes in position.

6. The apnea monitor of claim 4, wherein the output signal generated by the detector has a frequency dependent upon the beat frequency between the reflected radiation and the reference beam, which in turn is dependent upon the breathing rate of the subject.

7. The apnea monitor of claim 3, wherein the first optical element is a beamsplitter.

8. The apnea monitor of claim 2, further comprising a filter optically coupled to the detector for filtering ambient light.

9. The apnea monitor of claim 1, further comprising means for driving the laser to produce the radiation.

10. The apnea monitor of claim 1, further comprising an alarm for alerting one of the subject and another person of an alarm condition.

11. The apnea monitor of claim 10, wherein the alarm is an alarm selected from among tactile audible and visual alarms.

12. The apnea monitor of claim 1, further comprising means for transmitting an alarm signal to a location remote from the monitor to alert another person of an alarm condition.

13. The apnea monitor of claim 2, further comprising counter means in circuit with the processor for counting the time between the laser-generated radiation and the reflected radiation detected by the detector.

14. The apnea monitor of claim 2, wherein the detector is a photodetector.

15. The apnea monitor of claim 1, wherein the motion determination means includes means for correlating laser-generated radiation reflected by the subject and radiation directly received by the motion determination means from the laser to determine a beat frequency therebetween.

16. The apnea monitor of claim 1, further comprising a first optical element optically coupled to the laser for collimating the radiation generated by the laser to produce a coherent collimated radiation beam.

17. The apnea monitor of claim 2, further comprising an optical element optically coupled to the detector to converge the reflected radiation thereon.

18. The apnea monitor of claim 1, wherein said motion determination means comprises a data processing system for determining one of the instantaneous distance between the monitor and the selected area of the subject, the rate of movement of the subject, and the breathing rate of the subject.

19. The apnea monitor of claim 1, wherein the motion determination means comprises a data processing system having input-output means for allowing the input of user-selected data and for allowing the transfer of data from the processing system.

20. The apnea monitor of claim 19, wherein the data processing system further comprises a processor, and memory in circuit with the processor for storing data and a program for execution by the processor, the program upon execution determining one of the breathing rate, the change in position, a breathing pattern of the subject, and an apneic period.

21. The apnea monitor of claim 20, further comprising an alarm in circuit with the processing system for alerting one of the subject and another person of an alarm condition, the processing system generating an alarm output signal, wherein the alarm produces one of an audible signal, a visual signal and a tactile signal in response to the alarm output signal.

22. The apnea monitor of claim 1, wherein said illumination means, illuminates with ultrasonic wave energy and wherein said determination means determines a change by Fourier processing of a set of measurements of ultrasonic energy reflected from the subject.

23. The apnea monitor of claim 1, wherein said illumination means includes a laser.

28. The apnea monitor of claim 1, wherein said breathing rate determination means comprises

a detector positioned to receive the reflected radiation from the subject, said detector generating an output signal in response to said movement, and

a processor in circuit with the detector for correlating said output signal to said breathing rate of the subject.

29. The apnea monitor of claim 1, wherein said breathing rate determination means comprises a processor in circuit with the motion determination means for correlating said change in position to said breathing rate of the subject.

30. The apnea monitor of claim 1, wherein said breathing rate determination means comprises a data processing system for storing data associated with the change in position of the subject determined by said motion determination means, and a program for execution by the processor, the program upon execution determining the breathing rate or pattern of the subject to detect an apneic period.

24. A non-invasive method for monitoring breathing of a subject, comprising the steps of

illuminating the subject with radiated energy from an external radiation source,

detecting radiated energy reflected from a surface that moves as a result of breathing by the subject, and

processing the detected energy to identify motions indicative of the breathing rate of the subject.

25. The method of claim 24, wherein the external radiation source includes a laser and the energy is laser light and the steps of detecting and processing comprise

detecting laser-generated radiation reflected from the subject and producing electrical output signals in response to the reflected radiation incident thereupon, and

processing the electrical output signals to determine change of position of the subject.

26. The method of claim 24, further comprising the step of driving a laser to produce the radiated energy.

27. The method of claim 24, further comprising the step of alerting one of the subject and another person of an alarm condition in response to a cessation of breathing or change in the breathing rate.

31. The method of claim 24, wherein the steps of illumination comprises the step of emitting laser radiation along a first axis with a laser, optically coupling an optical network with the laser, said optical network including a first optical element for directing a portion of the laser radiation to form a reference beam.

32. The method of claim 31, wherein the step of detecting comprises the steps of positioning a detector to receive the reference beam and for detecting the laser-generated radiation reflected from the subject.

33. The method of claim 32, further comprising the steps of

combining the reflected radiation and the reference beam, and

determining a beat frequency corresponding to a Doppler shift that occurs between the reference beam and the radiation reflected from the subject,

wherein said beat frequency corresponds to said change in position of the subject.

34. The method of claim 33, wherein said step of processing further comprises the step of providing a processor in circuit with the detector for correlating said beat frequency to apnea of the subject.

35. The apnea monitor of claim 34, wherein the step of processing further comprises the steps of

counting extrema in an electrical signal generated by the detector, said extrema corresponding to interference fringes resulting from the reference beam and the reflected radiation, and

generating a signal indicative of changes in position of the subject, the processor determining apnea from lapses in said changes in position.

36. A method for monitoring breathing of a subject to detect an apnea event, comprising the steps of

illuminating the subject with radiation from a laser,

collecting return radiation reflected from a surface of the subject,

directing the collected laser radiation onto a detector,

generating an output signal with the detector indicative of movement or lack of movement of the subject as a function of breathing of the subject, and

processing the output signal to determine the breathing rate of the subject.

37. The method of claim 36, further comprising the step of performing a Doppler shift analysis of the laser radiation reflected from the subject.

38. The method of claim 37, further comprising the step of determining breathing rate of the subject from the Doppler analysis of the reflected radiation.

39. The method of claim 36, further comprising the steps of analyzing a speckle pattern generated by the reflected radiation, and determining the breathing rate of the subject from said speckle pattern.

40. The method of claim 36, further comprising the step of providing a control circuit for controlling the operation of the laser.