EFFECT OF INSPIRATORY FLOW ON BREATH SOUND ANALYSIS IN CHILDREN WITH ASTHMA

BACKGROUND: In order to determine the optimal breathing method for childhood lung sound analyses, it is important to study the effect of airflow on the parameters of lung sounds. METHODS: Sixty-one well-controlled children with atopic asthma (median; 12 years) participated. After confirming that there was no wheezing or respiratory symptoms, the lung sound spectrums of the inspiratory flow before and after inhalation of a β2 stimulant were analyzed. At the same time, their lung function was measured by a spirogram and the forced oscillation technique. RESULTS: Before β2 agonist inhalation, the area under the entire curve (AT) and 99% frequency (F99) in the lung sound of inspiratory flow around 2.0L/s due to slightly strong breathing were significantly higher than the lung sound of inspiratory flow around 1.0L/s due to rest breathing. However, no marked differences were observed in the lung sound parameters based on the lung sound spectrum. The improvement in the lung sound parameters after β2 agonist inhalation was clearer at an inspiratory flow around 1.0L/s than that around 2.0L/s. CONCLUSION: The present study showed that changes after β2 agonist inhalation and the correlation with the lung function parameters were clear during resting breathing. This method may be used for the long-term montoring of children with asthma.