BREATHING SOUND ANALYSIS FOR ESTIMATION OF AIRLOW RATE

• US 20080243017A1
• Filed: 03/28/2007
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Abandoned Application

• Current Assignee: TR Technologies Incorporated
• Original Assignee: TR Technologies Incorporated
• Inventors: Yadollahi, Azadeh, Moussavi, Zahra
• Application Number:
  US11/692,745
• Publication Number:
  US 20080243017A1
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6815 Ear
• CPC Class Codes: A61B 5/6822 Neck
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Apparatus for use detection of apnea includes a microphone mounted in the ear of the patient for detecting breathing sounds and a second external microphone together with an oximetric sensor. A transmitter at the patient compresses and transmits the signals to a remote location where there is provided a detector module for receiving and analyzing the signals to extract data relating to the breathing. The detector uses the entropy or range of the signal to generate an estimate of air flow while extracting extraneous snoring and heart sounds and to analyze the estimate of air flow using Otsu'"'"'s threshold to detect periods of apnea and/or hypopnea. A display provides data of the detected apnea/hypopnea episodes and related information for a clinician.

Claims

1. Apparatus for use in analysis of breathing of a patient comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals to generate an estimate of air flow;

and a display for displaying for a clinician the estimated air flow rate relative time;

wherein the detector module is arranged to calculate a function representing the range of the signal or the entropy of the signal providing an estimate of air flow during breathing.

2. The apparatus according to claim 1 wherein the detector module is arranged to cancel heart sounds from the function.

3. The apparatus according to claim 1 wherein the function using entropy is defined by the following formula.

4. The apparatus according to claim 1 wherein the function is the range of signal which is defined as the log of the difference between minimum and maximum of the signal within each short window (i.e. 100 ms) of data.

5. The apparatus according to claim 1 wherein the extraneous sounds are removed by the detector module prior to flow estimation.

6. The apparatus according to claim 1 wherein the display is arranged to display the estimated air flow versus time in any desired time length being chosen by the user.

7. The apparatus according to claim 1 wherein the display is capable of zoom-in and zoom-out functions in the same window.

9. The apparatus according to claim 1 wherein the microphone is arranged to be located in the ear of the patient.

10. The apparatus according to claim 9 wherein the microphone in the ear includes a transmitter arranged for wireless transmission to a receiver.

11. The apparatus according to claim 1 wherein the apparatus is arranged such that inspiration and expiration are monitored by an initial calibration wherein the patient is instructed to initialize the system by taking a deep breath, hold it, start up of the monitoring system, then exhale and continue breathing.

12. The apparatus according to claim 1 wherein an estimate of flow rate is calibrated using a look-up table of previously measured flow-sound relationship data that is sorted based on characteristics of the subjects.

13. The apparatus according to claim 1 wherein the characteristics in the look-up table include BMI, gender, height, neck circumference, and smoking history of the subject.

14. The apparatus according to claim 1 wherein the detector module is arranged to cancel heart sounds.

15. Apparatus for use in use in analysis of breathing of a patient during sleep comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals to generate an estimate of air flow during inspiration and expiration;

and a display for displaying the data for a clinician;

wherein the apparatus is arranged such that inspiration and expiration are monitored by an initial calibration wherein the patient is instructed to initialize the system by taking a deep breath, hold it, start up of the monitoring system, then exhale and continue breathing.

8. The apparatus according to claim 16 wherein the display is capable of playing the breathing sounds in any data window.

16. The apparatus according to claim 15 wherein an estimate of flow rate is calibrated using a look-up table of previously measured flow-sound relationship data that is sorted based on characteristics of the subjects.

17. The apparatus according to claim 16 wherein the characteristics in the look-up table include BMI, gender, height, neck circumference, and smoking history of the subject.

18. Apparatus for use in use in analysis of breathing of a patient during sleep comprising:

a microphone arranged to be located on the patient for detecting breathing sounds;

a detector module for receiving and analyzing the signals to extract data relating to the breathing;

the detector module being arranged to analyze the signals to generate an estimate of air flow during inspiration and expiration;

and a display for displaying the data for a clinician;

wherein an estimate of flow rate is calibrated using a look-up table of previously measured flow-sound relationship data that is sorted based on characteristics of the subjects.

19. The apparatus according to claim 18 wherein the characteristics in the look-up table include BMI, gender, height, neck circumference, and smoking history of the subject.