RT Journal Article
SR Electronic
T1 Coherence analysis of breath sounds during bronchial provocation test in children
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P4531
VO 44
IS Suppl 58
A1 Yoon Ha Hwang
A1 Sung Won Kim
A1 Hiroshi Odajima
A1 Hiroshi Nakano
YR 2014
UL http://erj.ersjournals.com/content/44/Suppl_58/P4531.abstract
AB Background: Changes in the lung sound spectra depend on many factors such as sound production sites, local airflow velocity, and sound transmission. Thus, the objective of this study is to analyze the relationship between change in tracheal sounds and lung sounds during BPT (bronchial provocation test), thereby illuminating the mechanism for the spectral changes of breath sounds. Methods: The subjects consisted of 20 well-controlled asthmatic male patients of 8 to 15 years old. During BPT, we recorded the breath sounds at the right chest locations and analyzed them using FFT (Fast Fourier Transform). We calculated the coherences between tracheal sounds (as reference) and lung sounds. We also estimated the transmission of sound from the trachea to the chest walls. Data which contained wheezes were excluded from the analysis. Results: During the expiration period, coherence decreased with RT-Ach (respiratory threshold-acetylcholine) and increased with bronchodilator use. Sound power increased with RT-Ach, and returned to baseline with bronchodilator use. These results were statistically significant (p<0.05). The sound transmission did not change during BPT. It is suggested that the sound origin migrated to the periphery with bronchoconstriction during the expiration period. Conclusions: In asthmatic patients, the mechanism of breath sound changes during bronchoconstriction did not cause changes in transmission, but lead to migration of the sound production site to the periphery during expiration.