Treatment evaluation using lung sound analysis in asthmatic children

Non-invasive assessment of treatment and prediction of attacks in asthmatic children do not yet exist. Lung sound analysis can non-invasively evaluate airway obstruction. We used a recently developed technology for analysing lung sounds using ic700 (index of the chest wall at 700 Hz, sound intensity at 700 Hz) to evaluate response to inhaled corticosteroid (ICS) in asthmatic children.

Seventy asthmatic children, including infants, underwent lung sound recording in the asymptomatic state prior to and 1, 2, 4, 6 and 8 weeks after ICS treatment, and asthma control was assessed at 10 weeks. The ic700 scores at 4, 6 and 8 weeks were compared with the presence of attack during the following 2 weeks. Subjects were divided into uncontrolled and well-controlled groups.

The mean ic700 scores of all subjects significantly reduced after 8 weeks of treatment. The mean scores of the uncontrolled group were significantly higher than those of the well-controlled group at 4, 6 and 8 weeks after starting treatment. The ic700 cut-off value for predicting asthma attacks within 2 weeks following the evaluation was set at 0.0. After 6 weeks of treatment, the area under the curve was 0.92 ± 0.04; the sensitivity, specificity and positive and negative predictive values were 83%, 88% and 88% and 84%, respectively. Similar results were observed at 4 and 8 weeks.

The ic700 score is useful in assessing the effects of ICS treatment, predicting attack symptoms and identifying asymptomatic asthmatic children at a high risk for asthma attack.