Clinical Application of High-pitched Breath Sound in Children with Asthma.

OBJECTIVE

Breath sound parameters have been suggested to be a new biomarker of airway conditions in asthmatic patients. We investigated new breath sound parameters to determine their utility for evaluating asthmatic children.

METHODS

Fifty-seven children (mean age, 9.0 years, 6-16 years) were included in the present study. The new breath sound parameters, the area under the curve (AUC)>1,000 Hz (A1000 [dBm·Hz]) and the ratio of the A1000 to the total AUC at 100 Hz to the highest frequency of the dBm power spectrum (AT) (A1000/AT [%]) were measured before and after β2 agonist inhalation. Spirography and the forced oscillation technique were also used to evaluate all subjects.

RESULTS

The value of A1000 was negatively correlated with the FEV1 (p=0.028). The increase in the ΔFEV1 was correlated with the decrease in the ΔA1000 (p=0.001) and the ΔA1000/AT (p=0.036).

CONCLUSIONS

The A1000 indicates the airway condition, and the ΔA1000 and the ΔA1000/AT well describe the dilatation of the airways. These parameters are useful for the assessment of bronchial reversibility in asthmatic children.