Does bronchodilator responsiveness in infants with bronchiolitis depend on age?

Abstract

To assess the relation between age and bronchodilator responsiveness in infants with bronchiolitis. In 41 infants (age, 2 to 18 months) with bronchiolitis, lung function was measured with the raised volume rapid thoracoabdominal compression technique before and after salbutamol inhalation. Lung function was quantified in terms of timed volumes (FEV(0.5), FEV(0.75), and FEV(1.0)). A significant change was defined as a postbronchodilator value that differed from baseline by more than twice the within-subject coefficient of variation. For the group, postbronchodilator values did not differ significantly from baseline (DeltaFEV(0.5), 3.8% +/- 9.3%; DeltaFEV(0.75), 3.5% +/- 9.5%; and DeltaFEV(1.0), 4.0 +/- 9.8%). Eleven subjects showed significantly increased timed volumes; 3 presented with a decreased lung function; the remaining patients failed to show a significant change. The mean age of subjects with improved lung function did not differ significantly from the mean age of those with no or paradoxical responses (9.7 +/- 4.7 vs 8.1 +/- 4.1 months); there was no correlation of age with the size of the bronchodilator response. The results of the current study indicate that bronchodilator responsiveness in infants with bronchiolitis is not age-dependent.