Method of determining lung condition indicators
View Patent ↗A method and a microprocessor controlled device for use in medical evaluation of the pulmonary system. The method and device incorporate two different non invasive evaluative techniques. Passive auscultation provides indicators of lung condition. Active auscultation, a different evaluative technique, provides information or indications generally not available or provided from passive auscultation. Combining the information from both techniques greatly improves the ability to provide effective medical treatment.
1. A method of determining a condition of at least one lung of a patient comprising:
making an active measurement of the at least one lung by non-invasively introducing a signal through contact with a thoracic skin surface of the patient from a transducer comprising one or more audible frequencies into the at least one lung and receiving the at least one audible frequency signal during or upon passage through the at least one lung;
making a passive measurement of the at least one lung by receiving at least one naturally occurring sound associated with breathing by the patient; and
determining a condition of the at least one lung by combining data associated with the active measurement with data associated with the passive measurement.
2. The method of claim 1 wherein making an active measurement further includes determining one or more variables from the received signal.
3. The method of claim 2 wherein one variable of the one or more variables is the velocity of the received signal.
4. The method of claim 3 wherein the velocity is determined over a range of frequencies associated with the audible frequency signal.
5. The method of claim 2 wherein one variable of the one or more variables is the phase of the received signal.
6. The method of claim 2 wherein one variable of the one or more variables is the dispersion of frequencies of the received signal over a range of frequencies.
7. The method according to claim 1 further comprising ceasing to introduce a sound signal having one or more audible frequencies while making a passive measurement of the at least one lung.
8. The method according to claim 1 wherein the data comprises a ratio of an amplitude of the received audible frequency signal at a first frequency versus the amplitude of the received audible frequency signal at a second frequency.
9. The method according to claim 1 wherein the data comprises a ratio of a velocity of the received signal at a first frequency versus a velocity of the received signal at a second frequency.
10. The method according to claim 1 wherein the data comprises a ratio of an attenuation of the received signal at a first frequency versus the attenuation of the received signal at a second frequency.
11. A method of determining the condition of a patient's lung, the method including the steps of:
injecting a signal comprising audible frequencies through the patient's lung via a thoracic skin surface;
recording the injected signal after the injected signal has passed through the patient's lung and processing the signal to determine a first set of criteria indicative of a condition of the lung;
monitoring naturally occurring breath sounds of the patient's lung;
processing the breath sounds of the patient's lung to determine a second set of criteria indicative of a condition of the lung; and
narrowing the number of criteria indicative of a condition of the lung by comparing the first set of criteria from the injected signal with the second set of criteria from the naturally occurring breath sounds.
12. The method of claim 11 wherein the first set of criteria is selected from a group comprising a cross-correlation function, a coherence function and a transfer function.
13. The method of claim 11 wherein the second set of criteria is selected from a group comprising one or more of wheeze rate, wheeze amplitude, rhonchi rate, rhonchi amplitude, whistle rate, whistle amplitude, crackle rate and crackle amplitude.
14. The method of claim 11 wherein recording the injected signal includes receiving the injected signal with one or more transducers.
15. The method of claim 11 wherein monitoring the naturally occurring breath sounds includes monitoring one or more transducers.
16. The method of claim 11 wherein injecting the signal does not occur at the same time as monitoring the naturally occurring breath sounds.
17. Apparatus for evaluating the condition of a lung of a patient, the apparatus comprising:
one or more emitting transducers introducing a signal to a thoracic skin surface of the patient wherein the signal comprises audible frequencies into the lung;
one or more receiving transducers that receive the introduced signal after it has passed through at least part of the lung; and
a processing unit that
monitors the received signal and determines a first set of indicators of a condition of the lung based on the received signal, and
monitors one or more naturally occurring sounds associated with breathing by the patient and determines a second set of indicators of a condition of the lung based on the one or more monitored naturally occurring sounds, and
compares the first and second set of indicators, and provides a third set of indicators corresponding to a portion of overlap of the first and second sets of indicators respectively, the third set of indicators being indicators of lung condition based upon both the introduced signal and the naturally occurring sounds.
18. Apparatus according to claim 17 wherein the one or more receiving transducers also monitor naturally occurring sounds associated with breathing by the patient.
19. Apparatus according to claim 18 configured to cease introduction of sound during monitoring of naturally occurring sounds associated with breathing by the patient.