A Passive Acoustic Technique to Enhance Lung Diseases Diagnostic

Abstract

Abstract. Multiple lung obstructive and restrictive lung diseases are considered to experiment a new methodology based on Passive Time Delay Technique (PTDT). Lung sounds were recorded using a multichannel stethoscope on 32 healthy subjects, 20 COPD patients and 20 patients with different lung disorders. The sensors were distributed on the posterior and anterior chest wall. During recordings, all participants were breathing at matching airflow rates. Calculated time delay (TD) was identified for inspiration phase and an average TD value was provided after three repetitive measurements for each inspiration phase. TD computed in COPD patients: 440 ± 87 % (P < 0.05) was remarkably greater than time delay computed with normal subjects: 160 ± 10 % (P < 0.05) it was also greater than TD recorded with different other lung disorders patients. Results were presented as mean ± SD, standard deviation of time delay in ms. Significant P values (P < 0.05) were indicated using Wilcoxon test. Preliminary results are very encouraging to develop this technique and enhance lung diseases monitoring.