A meta-analysis of randomized controlled trials evaluating the efficacy of epinephrine for the treatment of acute viral bronchiolitis

Background: Controversy exists surrounding the use of bronchodilators for bronchiolitis. Epinephrine hydrochloride is being used with increasing frequency in this group; however, its efficacy has not been systematically reviewed. Objective: To systematically review randomized controlled trials comparing inhaled or systemic epinephrine vs placebo or other bronchodilators. Data Sources: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, primary authors, and reference lists. Study Selection: Studies were included if they (1) were randomized, controlled trials; (2) involved children 2 years or younger with bronchiolitis; and (3) presented quantitative outcomes. Data Extraction: Two reviewers independently extracted data and assessed study quality. Data Synthesis: We included 14 studies (7 inpatient, 6 outpatient, and I patient status unknown). Thirteen of forty-five comparisons were significant. Among outpatients, results favored epinephrine compared with placebo for clinical score at 60 minutes (standardized mean difference [SMD], -0.81; 95% confidence interval [CI], -1.56 to -0.07), oxygen saturation at 30 minutes (weighted mean difference [WMD], 2.79; 95% CL 1.50-4.08), respiratory rate at 30 minutes (WMD, -4.54; 95% CL -8.89 to -0.19), and improvement (odds ratio, 25.06; 95% CL 4.95-126.91); among inpatients, for clinical score at 60 minutes (SMD, -0.52; 95% CI, -1.00 to -0.03). Among outpatients, results favored epinephrine compared with albuterol sulfate (salbutamol) for oxygen saturation at 60 minutes (WMD, 1.91-195% Cl, 0.38-3.44), heart rate at 90 minutes (WMD, -14.00; 95% CI, -22.95 to -5.05), respiratory rate at 60 minutes (WMD, -7.76; 95% CI, -11.35 to -4.17), and improvement (odds ratio, 4.51; 95% CI, 1.9310.53); among inpatients, respiratory rate at 30 minutes (WMD, -5.12; 95% CL -6.83 to -3.41). Conclusions: Epinephrine may be favorable compared with placebo and albuterol for short-term benefits among outpatients. There is insufficient evidence to support the use of epinephrine among inpatients. Large, multicentered trials are required before routine use among outpatients can be strongly recommended.