Method and apparatus for the diagnosis of sleep apnea utilizing a single interface with a human body part

• US 5,398,682 A
• Filed: 11/15/1993
• Issued: 03/21/1995
• Est. Priority Date: 08/19/1992
• Status: Expired due to Term

• Current Assignee: Lawrence A. Lynn
• Original Assignee: Lawrence A. Lynn
• Inventors: Lynn, Lawrence A.
• Primary Examiner(s): Sykes, Angela D.
• Application Number:
  US08/151,901
• Time in Patent Office: 491 Days
• Field of Search: 128/716, 128/719, 128/721-724, 128/903, 128/633, 128/604-607, 128/671, 128/670
• US Class Current: 600/335
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

A device for diagnosing sleep apnea by identifying desaturation and resaturation events in oxygen saturation of a patient'"'"'s blood. The slope of the events is determined and compared against various information to determine sleep apnea.

Claims

1. A sleep apnea treatment device, comprising:

an oximeter, having an output signal indicating an oxygen saturation of a patient'"'"'s blood;

a processor element, responsive to said signal indicating oxygen saturation, for identifying at least two consecutive desaturation events, in which said oxygen saturation falls below a baseline level by a predetermined amount and for a predetermined time,

said processor element identifies each desaturation event only when it also includes a resaturation, immediately following said desaturation and coupled with each said desaturation, in which the oxygen saturation rises,

said processor element for calculating a slope of each said desaturation event representing a rate of change per unit time of fall of oxygen saturation,

said processor element for comparing said calculated slopes with value of slopes which are determined in advance to be indicative of sleep apnea and making a diagnosis of sleep apnea based on said comparing and wherein said comparing is also based on at least one slope of said resaturation; and

a positive pressure generating device, constructed and arranged to administer positive airway pressure through a patient'"'"'s nasal pharynx, and wherein said processing element actuates said positive pressure activating device upon identification of said at least two consecutive slopes, said positive pressure generating device being activated by oxygen saturation of the patient to thereby mitigate further desaturation.

2. An apparatus as in claim 1 wherein said processing element compares said consecutive slopes with an absolute number which is likely to indicate sleep apnea.

3. An apparatus as in claim 1 wherein said processing element compares said consecutive slopes with other slopes taken at different times.

4. An apparatus as in claim 1 wherein said processing element includes means for calculating a ratio of resaturation slope to desaturation slope and comparing said ratio with a predetermined number to diagnose sleep apnea.

5. An apparatus for treating sleep apnea comprising:

an oximetry sensor of a type which determines an oxygen saturation of a patient'"'"'s blood;

a microprocessor, programmed to recognize outputs from said sensor and to calculate an oxygen saturation of a patient'"'"'s blood as a function of time from said outputs, and to recognize a coupled desaturation/resaturation occurrence indicative of sleep apnea, said occurrence including;

a. a desaturation event when said oxygen saturation falls a predetermined amount in a predetermined time, and

b. a resaturation event when said oxygen saturation rises a predetermined amount in a predetermined time within a predetermined time after said desaturation event,

said microprocessor also including means for comparing a slope of desaturation of said desaturation event, with a slope of resaturation of said resaturation event, and using said comparison to diagnose sleep apnea,

a positive pressure generator for administering positive airway pressure through the patient'"'"'s nasal pharynx; and

said microprocessor including means for activating said positive pressure generator upon identification of said occurrence of sleep apnea so that upon identification of said occurrence, said positive pressure generator is activated to the patient to thereby mitigate further desaturation.

6. A device for diagnosing sleep apnea, comprising:

an oximeter, having an output signal indicating an oxygen saturation of a patient'"'"'s blood;

a processor, operating to;

1) identify a first desaturation event, in which said oxygen saturation falls below a baseline level by a predetermined amount for a predetermined time,

2) identify a second desaturation event, in which said oxygen saturation falls below a baseline level by a predetermined amount and for a predetermined time; and

3) trigger a storage of said continuously recorded information for a predetermined time responsive to said identifying said first and second desaturation events, and otherwise commanding that said continuously recorded information not be stored.

7. A method for identification of sleep apnea and for determining an optimal level of nasal positive pressure for the treatment of said identified apnea, the method comprising the steps of:

a. disposing an oximeter adjacent to a single human body part and recording continuous measurement of oxygen saturation as a function of time to derive an oxygen saturation waveform;

b. defining a time interval for calculation of a slope of the oxygen saturation;

c. using a computer to continuously calculate said slope along said waveform, using said time interval;

d. continuing executing said steps b and c and using the computer to identify at least two consecutive slopes which fall within a specific range;

e. upon said identification in said step d), using the computer to initiate a preset positive pressure to the nasal pharynx with a positive pressure device; and

f. subsequent to said initiation of said nasal positive pressure, continuing to calculate said slopes of said oximetry waveform to determine efficacy of said nasal positive pressure in mitigating further presence of sleep apnea as defined by the absence of said consecutive slopes.

8. The method of claim 7 further including the step of comparing at least the first and second slope of said consecutive slopes and initiating said nasal positive pressure based on said comparing.

9. The method of claim 7 further including the step of identifying at least a first and a second consecutive desaturation event in which the oxygen saturation falls below a baseline level for a predetermined amount and for a predetermined time, and wherein said calculated slopes are calculated during said events.