Bronchodilator responsiveness in wheezy infants and toddlers is not associated with asthma risk factors.

BACKGROUND There are limited data assessing bronchodilator responsiveness (BDR) in infants and toddlers with recurrent wheezing, and factors associated with a positive response. OBJECTIVES In a multicenter study of children ≤ 36 months old, we assessed the prevalence of and factors associated with BDR among infants/toddlers with recurrent episodes of wheezing. METHODS Forced expiratory flows and volumes using the raised-volume rapid thoracic compression method were measured in 76 infants/toddlers [mean (SD) age 16.8 (7.6) months] with recurrent wheezing before and after administration of albuterol. Prior history of hospitalization or emergency department treatment for wheezing, use of inhaled or systemic corticosteroids, physician treatment of eczema, environmental tobacco smoke exposure, and family history of asthma or allergic rhinitis were ascertained. RESULTS Using the published upper limit of normal for post bronchodilator change (FEV(0.5)  ≥ 13% and/or FEF(25-75)  ≥ 24%) in healthy infants, 24% (n = 18) of children in our study exhibited BDR. The BDR response was not associated with any clinical factor other than body size. Dichotomizing subjects into responders (defined by published limits of normal) or by quartile to identify children with the greatest change from baseline (4th quartile vs. other) did not identify any other factor associated with BDR. CONCLUSIONS Approximately one quarter of infants/toddlers with recurrent wheezing exhibited BDR at their clinical baseline. However, BDR in wheezy infants/toddlers was not associated with established clinical asthma risk factors.