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.
To systematically review randomized controlled trials comparing inhaled or systemic epinephrine vs placebo or other bronchodilators.
MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, primary authors, and reference lists.
Studies were included if they (1) were randomized, controlled trials; (2) involved children 2 years or younger with bronchiolitis; and (3) presented quantitative outcomes.
Two reviewers independently extracted data and assessed study quality.
We included 14 studies (7 inpatient, 6 outpatient, and 1 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% CI, 1.50-4.08), respiratory rate at 30 minutes (WMD, −4.54; 95% CI, −8.89 to −0.19), and improvement (odds ratio, 25.06; 95% CI, 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; 95% CI, 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, 1.93-10.53); among inpatients, respiratory rate at 30 minutes (WMD, −5.12; 95% CI, −6.83 to −3.41).
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.