Responses to inhaled bronchodilators in infancy are not linked with asthma in later childhood

Many doctors consider wheezing infants and young children who respond to beta-adrenergic agents to be asthmatics, or at least at risk for later asthma. The aim of this study was to compare responses to inhaled albuterol and racemic epinephrine in infancy between children with and without asthma later in childhood. In a crossover study setting, 100 acutely wheezing infants aged less than 24 months were randomized to receive inhalations of either racemic epinephrine and placebo, or albuterol and placebo. Clinical evaluation consisted of measurements of respiratory rate, heart rate, and oxygen saturation, and clinical assessment of the respiratory distress assessment instrument (RDAI) score, consisting of wheezing and chest indrawings. The asthma status of the children was evaluated at three clinical follow-up visits, at 4.0, 7.2, and 12.3 (median) years of age. Responses to bronchodilating agents, when respiratory rates and RDAI scores were used as outcome measures, were not different in future asthmatics compared to nonasthmatics. However, oxygen saturation was significantly higher after albuterol inhalation in children who had asthma at all three visits (92.67% confidence interval (CI), 91.39-93.96) than in those without asthma at these visits (92.52% CI, 91.79-93.25), but lower, correspondingly, after racemic epinephrine (91.97% CI, 90.74-93.19 vs. 93.04% CI, 92.29-93.79) and placebo (91.38% CI, 90.49-92.28 vs. 93.12% CI, 92.60-93.65) inhalations (P = 0.04). In conclusion, we were not able to confirm that future asthmatics respond better than future nonasthmatics to bronchodilating agents during wheezing in infancy. More studies are needed to characterize the subset of infants who benefit from bronchodilating treatment in infancy.