Method and apparatus for diagnosing respiratory disorders and determining the degree of exacerbations

• US 7,785,262 B2
• Filed: 04/25/2005
• Issued: 08/31/2010
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: Convergent Engineering, Inc., University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: Neil Euliano, University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Melker, Richard J., Euliano, Neil R.
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): Natnithithadha; Navin
• Application Number:
  US11/122,278
• Publication Number:
  US 20060241506A1
• Time in Patent Office: 1,954 Days
• Field of Search: 600/300, 600/301, 600/481, 600/483, 600/484, 600500-504, 600529-543
• US Class Current: 600/484
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• 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 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61B 5/1073 Measuring volume, e.g. of limbs
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/4884 inducing physiological or psychological stress, e.g. applications for stress testing
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/1005 with O2 features or with parameter measurement
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)

Abstract

Disclosed herein are apparatuses and methods to monitor respiration and abnormal respiration events utilizing plethysmography. The apparatuses and methods provide an alternative to conventional respiration monitoring methods while enabling accurate yet minimally interruptive and invasive monitoring of respiration. The methods and apparatuses may be employed in the context of sleep studies to determine respiratory related sleep disorders.

Claims

1. A method of monitoring respiration in a patient, said method comprising:

securing a pulse oximeter probe to a central source site of said patient wherein said probe is configured to generate a plethysmography signal stream from said central source site;

processing, using a computer, said signal stream received from said probe to obtain a separate arterial component signal and venous impedance component signal, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying, using a computer, midpoints or minimum values between said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting, using a computer, said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal; and

evaluating said arterial component signal, or venous impedance component signal, or both, to determine respiratory rate, occurrence of an inspiratory event, expiratory event, air restriction or air obstruction, or a combination thereof,

wherein said central source site is a nasal septum, a nasal alar, a pre auricular region, a post auricular region, cheek, or ear canal of said patient.

2. The method of claim 1, wherein said central source site is the nasal septum or nasal alar.

3. The method of claim 1, wherein said evaluating comprises analyzing two or more datasets of signal information obtained at separate time periods.

4. The method of claim 1, wherein processing said signal stream information comprises processing plethysmography signal information generated while said patient is asleep.

5. A method of monitoring respiration in a patient, said method comprising:

securing a pulse oximeter probe to a central source site of said patient wherein said probe is configured to generate a plethysmography signal stream;

processing, using a computer, said signal stream received from said probe to obtain a venous impedance component signal, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying, using a computer, midpoints or minimum values between said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting, using a computer, said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal; and

observing changes in venous impedance component signal correlating with respiratory rate, inspiratory or expiratory events, or combination thereof, of said patient,

wherein said central source site is a nasal septum, a nasal alar, a pre auricular region, a post auricular region, cheek, or ear canal of said patient.

6. A system for monitoring respiration of a patient comprising

at least one pulse oximeter probe configured for securing to a central source site of said patient and effective to generate a plethysmography signal stream;

and

a computer communicatingly connected to said at least one pulse oximeter probe, said computer comprising at least one processing module, a first computer-readable program code module for causing said computer to process signals of said at least one pulse oximeter probe to obtain an arterial component signal or a venous impedance component signal, or both, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying midpoints or minimum values between said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal, and a second computer-readable program code module for causing said computer to analyze said arterial component signal or venous impedance component signal, or both to determine an inspiratory event, expiratory event, an air restriction event or an air obstruction event, or a combination thereof.

7. The system of claim 6, wherein said computer further comprises a display screen.

8. A computer program product for use with a computer comprising at least one processing module, said product comprising:

a computer-usable medium comprising computer readable program code modules embodied in said computer-usable medium;

computer readable first program code module for causing said computer to process plethysmography signals obtained from a pulse oximeter probe by separating out an arterial component signal stream and a venous impedance component signal stream, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying midpoints or minimum values between said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal; and

computer-readable second program code module for causing said computer to analyze said arterial component signal stream or said venous impedance signal stream, or both, to determine an occurrence of an abnormal respiration event.

9. A device useful for diagnosing a respiratory condition, said device comprising a computer configured to communicate with at least one pulse oximeter probe,

said computer comprising at least one processing module;

a first computer-readable program code module for causing said computer to process signals of said at least one pulse oximeter probe to obtain an arterial component signal or a venous impedance component signal, or both, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying midpoints or minimum values between said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal, and a second computer-readable program code module for causing said computer to analyze said arterial component signal or venous impedance component signal, or both a respiratory condition.

10. The device of claim 9, further comprising a display screen effective to display information to a user of said device.

11. The device of claim 9, wherein said device comprises a calibrating mode and an operational mode.

12. The device of claim 11, wherein said calibrating mode allows said device to receive a first dataset of plethysmography signal information of a patient generated during respiration at a predetermined resistance, whereby said device is calibrated for said patient.

13. The device of claim 12, wherein after calibration, said device may receive a second dataset of plethysmography signal information from said patient in said operational mode such that said device may compare said second dataset with said first dataset and provide information on said display screen to assist a user of said device to diagnose a respiratory condition of said patient.

14. The device of claim 9, wherein said respiratory condition is a restriction or obstruction of the nasopharynx caused by an allergy, bacterial infection or viral infection;

sleep apnea which results in a temporary partial or complete obstruction of the posterior pharynx during phases of the sleep cycle;

restriction or obstruction of the trachea or bronchi caused by tracheomalacia, tracheal polyps and warts, or bronchitis;

or restriction or obstruction of the lower airways, caused by asthma, viral infection, bacterial infection, cystic fibrosis or chronic obstructive pulmonary disease.

15. The device of claim 9, wherein said device weighs less than 10 kilograms, 8 kilograms, 6 kilograms, or 4 kilograms.

16. The device of claim 9, wherein said device is battery powered.

17. A method of diagnosing a respiration-related sleep disorder in a patient, said method comprising:

securing a pulse oximeter probe to a central source site of said patient wherein said probe is configured to generate a plethysmography signal stream from said central source site;

processing, using a computer, said signal stream received from said probe to obtain a separate arterial component signal and venous impedance component signal, wherein processing said signal stream comprises identifying peaks and troughs of said signal stream;

identifying, using a computer, midpoints or minimum values between-said peaks and troughs, wherein the interpolated line connecting said midpoints or minimum values represents said venous impedance component;

extracting, using a computer, said venous impedance component from said signal stream thereby obtaining said separate arterial component signal and separate venous impedance component signal and wherein processing said signal stream information comprises processing plethysmography signal information generated while said patient is asleep; and

evaluating said arterial component signal, or venous impedance component signal, or both, to determine occurrence of an inspiratory event, expiratory event, air restriction or air obstruction, or a combination thereof,

wherein said central source site is a nasal septum, a nasal alar, a pre-auricular region, a post auricular region, cheek, or ear canal of said patient.