Response to bronchodilators in school children with asthma and normal FEV1

Abstract

Background: Asthma is a chronic inflammatory disorder of the airways, associated with variable airflow obstruction that is at least partly reversible, either spontaneously or with treatment. When assessing asthma, FEV1 is often the only functional parameter considered.

Aim: To evaluate if there is a positive response to bronchodilators in school children with asthma and normal FEV1. To correlate this results with clinical parameters of disease.

Method: 190 asthmatic children with normal FEV1 were included and submitted to lung function testing with bronchodilation. We evaluated bronchodilator response (BDR) and questioned them about several clinical aspects (daily medication, rescue medication, asthma exacerbations, nocturnal symptoms and exercise-induced symptoms), in the past 3 months. We considered a normal FEV1 when it was 80% of the predicted value (PV) and a positive BDR when FEV1 increased for at least 12% after administration of bronchodilators.

Results: 85 male and 105 female patients; 75 were atopic; 25 patients had intermittent asthma, 48 mild persistent and 42 moderate persistent asthma. There was a positive BDR in 52 patients (I group). In this group, 15 patients referred nocturnal and/or exercise-induced symptoms vs. 138 from those with a negative BDR (II group). Regarding daily medication, 21/52 patients with positive BDR and 50/138 from those with negative BDR were on inhaled corticosteroids.

Conclusion: In this study 27.3% of asthmatic children had a positive BDR, although presenting normal FEV1. A positive BDR correlated with clinical parameters, mainly with recent asthma exacerbations.