Avaliação espirométrica de broncoespasmo induzido pelo exercício em crianças e adolescentes

Introduction: Exercise-induced bronchoconstriction (EIB) consists of transient narrowing of lower airways after exercise in the presence or absence of clinical recognition of asthma. The lack of symptoms control may lead to EIB, but the association between them is not well established. The evaluation of asthma control in children and adolescents presents a great challenge, due to the difficulty of correct symptoms perception in the pediatric population. Objective: Analyze spirometric parameters and the changes in respiratory variables in asthmatic children and adolescents with EIB. Methods: Observational study, with cross-cutting and prospective inclusions. Selected asthmatic children and adolescents from 7 to 17 years of age. After asthma control asses according to the Global Initiative for Asthma (GINA), Childhood Asthma Control Test (C-ACT) and Asthma Control Test (ACT), patients performed a pre-exercise spirometry test, requiring a baseline FEV1 . 80% of the predicted to submit to the bronchial challenge test according to the ATS 2013 protocol. Serial post-exercise spirometry was performed. EIB was defined as a fall in FEV1 of at least 10% from baseline. For normality verification was used Kolmogorov Smirnov test. The prevalence variables were analyzed by the chi-square test for independence. Unpaired sample T-test was conducted for the comparative analysis of the spirometry data variables obtained in the lung function test in the groups. The FEV1 values before and after the exercise challenge, intergroup, were compared with the variance analysis (ANOVA two way). It was considered a 5% significance (P < 0.05) in all tests. Results: Seventy participants were analyzed and EIB was positive in 41 (58.6%). According to C-ACT and ACT 20 (40,8%) of the symptomatic patients had negative challenge test, not being possible to observe statistical difference between symptomatic and non-symptomatic patients. However, symptoms insights noticed by parentes related to EIB had P-value equal to 0.001. There was an association between the occurrence of EIB and lower values of FEV1/FVC and MMEF25-75%. The fall percentage of FEV1 in approximately one third of the patients was more than 25%, showing a potential risk of serious events even in children and adolescents with seemingly normal pulmonary function. Moreover, it was observed that the fall percentage of the FEV1 was greater in the first five minutes after the exercise