Background: Bronchiolitis is an acute, highly infectious lower respiratory tract infection. Bronchodilators are commonly used in the management of bronchiolitis in North America but not in the United Kingdom.
Objectives: The objective of this review was to assess the effects of bronchodilators on clinical outcomes in infants with acute bronchiolitis.
Search strategy: In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library, Issue 1, 2006), MEDLINE (1966 to October 2005), EMBASE (2003 to September 2005) and the reference lists of articles. The files of one author (AG) were also reviewed.
Selection criteria: Randomized controlled trials (RCTs) comparing bronchodilators (other than epinephrine) with placebo in the treatment of bronchiolitis.
Data collection and analysis: For this updated review, one author assessed trial quality and extracted data. Unpublished data were requested from study authors when necessary.
Main results: Twenty-two clinical trials with 1428 infants with bronchiolitis were included in this review. In eight trials, with 468 infants, there was no improvement in clinical score for 43% of those treated with bronchodilators compared to 57% of those treated with placebo (odds ratio (OR) for no improvement 0.45, 95% confidence interval (CI) 0.15 to 1.29). There was a statistically significant but clinically modest improvement in the overall average clinical score (standardized mean difference (SMD) -0.48, 95% CI -0.62 to -0.33). However there was no statistically significant improvement in oxygenation overall (weighted mean difference (WMD) -0.57, 95% CI -1.17 to 0.03). Subgroup analyses showed a slightly greater effect size in outpatient studies, where there were shorter follow up durations, than in inpatient studies for both oximetry (outpatients WMD -0.84, 95% CI -1.59 to -0.10 versus inpatients WMD -0.25, 95% CI -1.18 to 0.67) and average clinical score (outpatients SMD -0.68, 95% CI -0.87 to -0.49 versus inpatients SMD -0.23, 95% CI -0.44 to -0.01). Bronchodilator recipients showed no improvement in the rate of hospital admission after treatment as outpatients (18% versus 26%, OR 0.70, 95% CI 0.36 to 1.35) or duration of hospitalization for inpatients (WMD 0.02, 95% CI -0.32 to 0.36). The inclusion of studies that enrolled infants with recurrent wheezing may have biased the results in favor of bronchodilators.
Authors' conclusions: Bronchodilators produce small short-term improvements in clinical scores. This small benefit must be weighed against the costs and adverse effects of these agents.