Graphical readout of laryngotracheal spectra and airway monitor

• US 5,058,600 A
• Filed: 01/08/1990
• Issued: 10/22/1991
• Est. Priority Date: 01/08/1990
• Status: Expired due to Term

• Current Assignee: University of Virginia
• Original Assignee: Eastern Virginia Medical School of The Medical College of Hampton Roads, The Center For Innovative Technology
• Inventors: Coleman, Robert F., Schechter, Gary L.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Nasser, Jr., Robert L.
• Application Number:
  US07/461,675
• Time in Patent Office: 652 Days
• Field of Search: 128/716, 128/719, 128/720
• US Class Current: 600/529
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7253 characterised by using transforms
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

A laryngotracheal airway spectra readout and monitor uses one or more miniature accelerometers placed on the outside of the neck of a patient to generate acoustic signals of patterns of breathing. The miniature accelerometers act as contact microphones which are sensitive to the physical vibration of breathing noise but otherwise insensitive to ambient and environmental noise. The acoustic signals are processed using Fast Fourier Transform (FFT) or other suitable acoustic analysis to generate a digitized spectra which may be printed out or recorded for later diagnostic analysis. The printoputs are in the form of a calibrated and normalized graphic readout which can be read by trained physicians or technicians in much the same way as EKGs. The digitized spectra is analyzed by comparing identified parameters of the spectra with a database of known parameters of normal and abnormal airways. Decision algorithms are then used to make diagnoses based on the comparison with the stored normal and abnormal parameter data, and the results of the diagnoses are presented graphically, either on screen or printed or both. Audible and/or visual alarms may also be generated if predetermined conditions are detected. In addition, records of current breathing analysis are stored and can be compared as a function of time to ascertain improvement or deterioration of a patient'"'"'s condition.

Claims

1. A laryngotracheal airway spectra readout comprising:

accelerometer means adapted to be placed on the outside of the neck of a patient, said accelerometer means generating a first electrical signal corresponding to the physical vibration of breathing noise;

pulmonary monitor means adapted to be attached to said patient for generating a second electrical signal corresponding to a phase of the patient'"'"'s breathing; and

frequency spectrum analyzer means connected to said accelerometer means and said pulmonary monitor means for analyzing said first and second electrical signals and generating a calibrated and normalized graphic readout.

2. A laryngotracheal airway spectra readout as recited in claim 1 wherein said frequency spectrum analyzer means includes means for performing fast Fourier transform analyses on said first electrical signal and for producing a three-dimensional spectral display.

3. A laryngotracheal airway spectra readout as recited in claim 1 wherein said frequency spectrum analyzer means includes means for performing fast Fourier transform analyses on said first electrical signal and for producing a long-term average display.

4. A laryngotracheal airway spectra readout as recited in claim 1 wherein said frequency spectrum analyzer means includes means for performing fast Fourier transform analyses on said first electrical signal and for producing a three-dimensional spectral display and a long-term average display.

5. A laryngotracheal airway spectra readout as recited in claim 1 further comprising analog to digital conversion means interposed between said accelerometer means and said pulmonary monitor means for converting said first and said second electrical signals to digital codes, said frequency spectrum analyzer means performing fast Fourier transform analyses on said electrical signal and producing a three-dimensional spectral display and a long-term average display.

6. A laryngotracheal airway monitor comprising:

accelerometer means adapted to be placed on the outside of the neck of a patient, said accelerometer means generating first electrical signal corresponding to the physical vibration of breathing noise;

analog-to-digital converter means connected to receive said first electrical signal and generating a digitized signal;

pulmonary monitor means adapted to be attached to said patient for generating a second electrical signal corresponding to a phase of the patient'"'"'s breathing;

database means for storing known parameters of normal and abnormal airways;

processor means for receiving said digitized signal and said second electrical signal and for performing an acoustic analysis to generate a digitized spectra, said processor means analyzing said digitized spectra by comparing identified parameters of the spectra with said known parameters in said database means and applying decision algorithms to make diagnoses of location and degree of an airway obstruction based on the comparisons with the stored normal and abnormal parameter data; and

readout means connected to said processor means for providing as an output the results of the diagnoses.

7. The laryngotracheal airway monitor as recited in claim 6 wherein records of current breathing analysis are stored in said database means and compared by said processor means as a function of time to ascertain improvement or deterioration of a patient'"'"'s condition.

8. The laryngotracheal airway monitor as recited in claim 6 wherein said readout means presents the results of the diagnoses graphically.

9. The laryngotracheal airway monitor as recited in claim 6 further comprising alarm means connected to said processor means for providing an alarm if predetermined conditions are detected.

10. A method of monitoring a patient'"'"'s laryngotracheal airway comprising the steps of:

generating a first electrical signal with an accelerometer placed on the outside of a patient'"'"'s neck, said electrical signal corresponding to the physical vibration of breathing noise;

converting said electrical signal to a digitized signal;

generating a second electrical signal corresponding to a phase of the patient'"'"'breathing;

storing in a database known parameters of normal and abnormal airways;

performing an acoustic analysis with a processor on said digitized signal and said second electrical signal to generate a digitized spectra;

using said processor to analyze said digitized spectra by comparing identified parameters of the spectra with said database of known parameters and applying decision algorithms to make diagnoses of location and degree of an airway obstruction based on the comparisons with the stored normal and abnormal parameter data; and

providing as an output of said processor the results of the diagnoses.

11. The method of monitoring a patient'"'"'s laryngotracheal airway recited in claim 10 further comprising the steps of:

storing records in said database of current breathing analysis; and

comparing stored records by said processor as a function of time to ascertain improvement or deterioration of the patient'"'"'s condition.