Bronchodilators for bronchiolitis

Background Bronchiolitis is an acute, viral lower respiratory tract infection affecting infants and is sometimes treated with bronchodilators. Objectives To assess the effects of bronchodilators on clinical outcomes in infants (0 to 12 months) with acute bronchiolitis. Search methods We searched CENTRAL 2013, Issue 12, MEDLINE (1966 to January Week 2, 2014) and EMBASE (1998 to January 2014). Selection criteria Randomized controlled trials (RCTs) comparing bronchodilators (other than epinephrine) with placebo for bronchiolitis. Data collection and analysis Two authors assessed trial quality and extracted data. We obtained unpublished data from trial authors. Main results We included 30 trials (35 data sets) representing 1992 infants with bronchiolitis. In 11 inpatient and 10 outpatient studies, oxygen saturation did not improve with bronchodilators (mean difference (MD) -0.43, 95% confidence interval (CI) -0.92 to 0.06, n = 1242). Outpatient bronchodilator treatment did not reduce the rate of hospitalization (11.9% in bronchodilator group versus 15.9% in placebo group, odds ratio (OR) 0.75, 95% CI 0.46 to 1.21, n = 710). Inpatient bronchodilator treatment did not reduce the duration of hospitalization (MD 0.06, 95% CI -0.27 to 0.39, n = 349). Effect estimates for inpatients (MD -0.62, 95% CI -1.40 to 0.16) were slightly larger than for outpatients (MD -0.25, 95% CI -0.61 to 0.11) for oximetry. Oximetry outcomes showed significant heterogeneity (I-2 statistic = 81%). Including only studies with low risk of bias had little impact on the overall effect size of oximetry (MD -0.38, 95% CI -0.75 to 0.00) but results were close to statistical significance. In eight inpatient studies, there was no change in average clinical score (standardized MD (SMD) -0.14, 95% CI -0.41 to 0.12) with bronchodilators. In nine outpatient studies, the average clinical score decreased slightly with bronchodilators (SMD -0.42, 95% CI -0.79 to -0.06), a statistically significant finding of questionable clinical importance. The clinical score outcome showed significant heterogeneity (I-2 statistic = 73%). Including only studies with low risk of bias reduced the heterogeneity but had little impact on the overall effect size of average clinical score (SMD -0.22, 95% CI -0.41 to -0.03). Sub-analyses limited to nebulized albuterol or salbutamol among outpatients (nine studies) showed no effect on oxygen saturation (MD -0.19, 95% CI -0.59 to 0.21, n = 572), average clinical score (SMD -0.36, 95% CI -0.83 to 0.11, n = 532) or hospital admission after treatment (OR 0.77, 95% CI 0.44 to 1.33, n = 404). Adverse effects included tachycardia, oxygen desaturation and tremors. Authors' conclusions Bronchodilators such as albuterol or salbutamol do not improve oxygen saturation, do not reduce hospital admission after outpatient treatment, do not shorten the duration of hospitalization and do not reduce the time to resolution of illness at home. Given the adverse side effects and the expense associated with these treatments, bronchodilators are not effective in the routine management of bronchiolitis. This meta-analysis continues to be limited by the small sample sizes and the lack of standardized study design and validated outcomes across the studies. Future trials with large sample sizes, standardized methodology across clinical sites and consistent assessment methods are needed to answer completely the question of efficacy.