Evaluation of the effect of inhaled β2 agonist on lung sounds of children with acute bronchiolitis.

BACKGROUND

Discussions regarding the treatment of acute bronchiolitis are ongoing. In this study, we investigated the effects of bronchodilators in infants with viral bronchiolitis using a lung sound analysis.

METHODS

Subjects were hospitalized children diagnosed with viral acute bronchiolitis who received inhaled short-acting inhaled beta 2-agonist (SABA). Lung sounds were collected before and after SABA inhalation, and imaged and quantified using a dedicated analysis system to objectively evaluate the effects of SABA. Furthermore, we investigated the influence of the child's clinical symptoms (clinical score, SpO2 value, hospitalization days, etc.), past history and family history of allergic diseases on the changes in lung sounds after SABA inhalation.

RESULTS

Twenty-six children (male: female = 16: 10, median age: 11 months) participated in the study, and wheezes on the lung sound spectrogram disappeared or decreased after inhalation of SABA in 57.7% (n = 15). However, no improvement in the low-pitched sounds of the lung spectrogram was evident, and no significant change was observed in the exhalation/inspiration power ratio. Although SpO2 in the group whose wheezes improved due to SABA inhalation was significantly lower than that in the group without improvement (p = 0.008), there were no significant differences in other factors.

CONCLUSION

The lung sound analysis confirmed that wheezes improved after SABA inhalation in half of the infants with acute viral bronchiolitis. However, since there was no improvement in clinical symptoms or low-pitched sounds, it was hypothesized that respiratory dysfunctions were caused by various mechanisms in infants with acute bronchiolitis.