title: Bronchodilator responsiveness in infants with bronchiolitis.
abstract: We evaluated 34 infants with bronchiolitis, (17 of both genders; mean age, 4.6 mos; ranges, 0.7-14.5 mos). The 20 inpatients were significantly younger than the 14 outpatients (2.6 vs. 8.2 months, P < 0.05), and more females were inpatients. Forced expiratory flows at functional residual capacity (VmaxFRC) were obtained at baseline, after aerosolized normal saline (NS), and metaproterenol (0.025 mL/kg in 2 mL NS). Flows were expressed as Z-scores, the difference between the measured and predicted flows, divided by the standard deviation for the predicted value. At baseline, outpatients were more obstructed than inpatients (-1.64 vs. -0.95, P < 0.05), infants > 2 months old were more obstructed than infants < or = 2 months old (-1.54 vs. -0.80, P < 0.05), and males more than females (-1.45 vs. -1.02, P < 0.05). Following NS the whole group had a small but significant decrease in Z-scores (-1.23 to -1.31, P < 0.05). Following metaproterenol, the younger infants had significantly (P < 0.05) higher Z-scores compared to baseline and NS (-0.80 vs. -0.86 vs. -0.59). However, no significant changes occurred in older infants. Females also had an increased flow after metaproterenol and were less obstructed than after NS (-1.11 vs. -0.86, P < 0.015). In males no increased flows occurred after metaproterenol (-1.45 vs. -1.48). Bronchodilator responsiveness did not relate to severity of airway obstruction, history of family asthma, allergy, or passive smoke exposure. We conclude that inhaled metaproterenol improves airway function in a subgroup of infants with bronchiolitis, but the subgroup could not clearly be identified because age and gender were confounding factors.
authors.affiliation: Indiana University School of Medicine, Department of Pediatrics, Indianapolis.
authors.forename: R S
authors.initials: RS
authors.lastname: Tepper
authors.forename: D
authors.initials: D
authors.lastname: Rosenberg
authors.forename: H
authors.initials: H
authors.lastname: Eigen
authors.forename: T
authors.initials: T
authors.lastname: Reister
mesh_terms: D000336:Aerosols; D000367:Age Factors; D001988:Bronchiolitis / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D016084:Bronchoconstriction / Q000187:drug effects*; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D006760:Hospitalization; D006801:Humans; D007223:Infant; D008297:Male; D009921:Metaproterenol / Q000008:administration & dosage / Q000627:therapeutic use*; D012737:Sex Factors; D012965:Sodium Chloride / Q000008:administration & dosage
chemical_list: D000336:Aerosols; D012965:Sodium Chloride; D009921:Metaproterenol