Changes in Lung Sounds During the Acute Stage of RSV Acute Bronchiolitis in Infants.

OBJECTIVE: Changes in the respiratory function over time in respiratory syncytial virus (RSV)-induced acute bronchiolitis were evaluated by a lung sound analysis. METHODS: We retrospectively examined changes in lung sound parameters over time in 54 children (median age, 7 months) diagnosed with RSV acute bronchiolitis. We evaluated the power of inspiratory and expiratory sounds using a conventional method and analyzed the frequency characteristics of inspiratory sounds using new automated analysis software program. We examined changes in these lung sound parameters over time during and after hospitalization and compared these data with those of age-matched healthy children. RESULTS: In 138 lung sound samples from 54 infants, the power of inspiratory and expiratory sounds was greatest within 4 days after the onset and improved over time. In contrast, the greatest changes in inspiratory sound parameters were observed at 5 to 10 days after the onset of RSV acute bronchiolitis. Some lung sound parameters in patients with RSV acute bronchiolitis did not return to normal even by 14 days after the onset. CONCLUSIONS: This finding is considered a characteristic of RSV acute bronchiolitis in infants and is meaningful in terms of post-treatment management.