Purpose: During the past 10 years, the acoustic
analysis of breath sounds has been used as a diagnostic tool in
patients suffering from obstructive respiratory diseases. Acoustic
analysis might be able to monitor the response to bronchodilator
therapy in a clinical setting. So far, few studies have been carried
out in asthmatic patients. To assess the responses of a sampling of
asthma patients to an inhaled bronchodilator (terbutaline) by means of
spectral analysis of the tracheal sound performed during forced
Material and methods: Seventeen
nonsmoking asthma patients (9 were male, 8 were female) who had been
suffering from the disease for ≥ 15 years were included in the study,
as were 15 normal subjects (7 were male, 8 were female). The average
age (± SD) was 56.5 ± 15.2 years (FVC, 2.7 ± 0.9 L[
63.4%]; FEV1, 1.5 ± 0.6 L [53.0%]). The tracheal
sounds were collected during three forced expiratory maneuvers with a
sampling frequency of 5,000 Hz and were analyzed by applying a
16-parameter autoregressive model.
centroid frequency decreased after the bronchodilator was given at
different flow segments between 1.2 and 0.4 L/s, with significant
changes between 0.6 and 0.4 L/s.
with asthma showed changes in the spectral acoustic analysis
frequencies after the administration of a bronchodilator drug
(terbutaline) during forced expiratory maneuvers.