A MICROCOMPUTER-BASED LUNG SOUNDS ANALYSIS

The use of a microcomputer in lung sound-analysis is described. The sy stem was used experimentally in order to evaluate automated auscultati on as a mean for improving the sensitivity of pulmonary health mass sc reening. The sound signals from four custom-made piezoelecric transduc ers, affixed at specific locations on the chest wall, and the breathin g flow signal produced by a pneumotachograph were amplified, filtered and digitized simultaneously at 4000 Hz per channel for 512 ms. The ac oustic data were transformed to the frequency domain to enable the cal culation of the power spectra. Those were averaged over successive run s and displayed as log power vs. frequency. The operator could assess the convergence of the spectral pattern using the on-line graphics and calculated parameters, and store the data once the noise level had re ached a preset level. This procedure was repeated during expiration, i nspiration and on breath arrest. The results of the off-line analysis of the lung sounds, combined with pulmonary function tests and a quest ionnaire, were used to identify lung pathology.