Abstract

Introduction: Eucapnic Voluntary Hyperventilation (EVH) is recommended for exercise-induced bronchospasm (EIB) diagnosis as a surrogate for exercise testing. There are controversies about the minimum minute ventilation rate for EVH to be considered valid in general clinical practice. Objective: To verify whether Forced Expiratory Volume in the first second (FEV1) responses considered diagnostic of Exercise-induced bronchospasm (EIB) are related to the ventilation rates (VR) achieved in Eucapnic Voluntary Hyperventilation (EVH) testing in asthmatic adolescents. Methods: A cross-sectional study was carried out with 72 asthmatics aged between 10 and 20 years. FEV1 was measured before and 5, 15 and 30 minutes after an EVH challenge which lasted 6 min and aimed at a target VR of 21 times the individual?s baseline FEV1. An EIB-compatible diagnosis was defined as a FEV1 post-challenge reduction >10% compared tobaseline. The EVH was repeated between 48 to 72 hours in those without EIB. Results: The achieved VR were not different between individuals with and without EIB (p=0.619). There were no differences either in the proportion of individuals with EIB-compatible response between those achieving low VR (<17-times baseline FEV1) compared to those achieving the target VR(p=0.878). A total of 14/36 patients had EIB at reassessment, with no differences in achieved VR compared to non-respondents(p=0.655).Conclusion: There were not association between achieved VR in the EVH challenge and an EIB-compatible response. Irrespective of the achieved VR, at least a second challenge should be conducted in individuals without EIB in the first test to rule out EIB diagnosis.