Exercise-induced bronchodilation (EIBd) in children undergoing Exercise-Induced Bronchoconstriction test (EIB) affects its interpretation

<bold>Background.</bold> EIB_d has been shown in asthmatic adults (J Appl Physiol 2002;92:2353-60). <bold>Aim.</bold> We assessed whether EIB_d occur also at end EIB in children suspected of exercise-induced bronchial hyperresponsiveness (EIBH), thus affecting EIB sensibility. <bold>Methods.</bold> 205 consecutive children (12±3 yrs), clinically suspected for EIBH, underwent an EIB test on cycle ergometer. Exercise protocol: four 1-min incremental steps to reach a heart rate of at least 90% max predicted to be maintained for 2 min. Forced Expiratory Volume at 1 s (FEV1) obtained at baseline (%predicted), and at 5, 10, 15 and 20 min after exercise (%baseline) assessed EIBH. Salbutamol spray (200-400μg according to children size) was administered, if necessary, at study end. Statistics: ANOVA. <bold>Results.</bold> Of the 205 children studied, 131 (64%) were negative, and 41 (23%) positive for EIBH (FEV₁post +0.3±3.4 and -11.4±4.7 %baseline, respectively). The remaining 26 (13%) children showed EIB_d (FEV₁post +11.9±5.0 %baseline) that occurred at 12.7±5.7 min after exercise. EIB_d was associated with lower baseline FEV₁ (88.5±14.9 %predicted) as compared to both negative (101.2±14.9 %predicted) and positive (96.1±14.5 %predicted) EIBH groups (p<0.0001 and p<0.05, respectively), indicating baseline bronchoconstriction. Finally, in the 13 (50%) EIB_d children in whom salbutamol was administered, no further increase in FEV₁ was observed (−2.9±6.4%), indicating post-exercise full bronchodilation.<bold>Conclusions.</bold> We conclude that EIB test should not be considered negative in symptomatic EIBd children and, hence, that they deserve some bronchodilator therapy or exercise premedication.