Source: Hartling L, Bialy LM, Vandermeer B, Tjosvold L, Johnson DW, et al.
Epinephrine for bronchiolitis. Cochrane Database of Systematic Reviews. 2011, Issue 6.
Art No: CD003123. DOI: 10.1002/14651858.CD003123.pub3.

Efficacy Endpoints: Admission Rate (Day 1)

Harm Endpoints: None

Narrative: Bronchiolitis, a viral respiratory infection in the first 2 years of life (most commonly caused by respiratory syncytial virus) often leads to significant use of healthcare resources. Optimal management strategies remain unclear, including pharmacotherapy for wheezing and shortness of breath.

This Cochrane review identified and assessed six studies of epinephrine versus placebo
with 995 children. The meta-analysis of these trials suggested that epinephrine reduced
the rate of hospitalization on day 1, risk ratio (RR) 0.67 (95% CI, 0.50 – 0.89).

These beneficial effects were not seen by day 7, although the analysis may have been
underpowered with only 3 studies of 875 children (RR 0.81, .95CI: 0.63 - 1.03), and
included trials of predominantly lower quality.

Of note, the review also identified that combination therapy using epinephrine and steroid for outpatients lowered 7-day admission rate when compared to placebo (RR = 0.65, 95% CI, 0.44 – 0.95), and improved clinical scores and respiratory rates. These findings, however, are based on a single high quality study.1

Finally, when epinephrine was compared to salbutamol in this review the rates of
admission within one day were similar, although inadequate power weakens these results
as well.

There was no significant harm identified in the review.

Caveats: This updated Cochrane review represents an important shift, adding 7 studies and altering the definition of bronchiolitis to mean a ‘first episode of wheezing’, a modification that standardized the inclusion criteria. Outcome measures were also changed to emphasize patient-centered outcomes such as admission rate and length of stay. The authors support the use of epinephrine in the treatment of outpatient bronchiolitis because of a reduction in hospitalization noted with the first 24 hours of treatment . In the 2004 version of the review no statistically apparent benefit of epinephrine was identified, and in the current review the benefit was not apparent at 7 days. However it seems quite possible that this was due to power and quality constraints in the studies reporting the 7 day outcome, which were smaller and less rigorous than studies reporting the 24-hour outcome.

One important update was including the synergistic effects of epinephrine and steroid to lower hospitalization rate, as reported in a single study. Additional studies are needed to replicate these results and to define the optimal combinations under specific conditions.

From this review, epinephrine appears helpful when administered early in disease
progression, i.e. in the outpatient/emergency department setting, although inpatient use
did not appear to provide any significant or identifiable benefits.

Author: Jeff Hom, MD

Published/Updated: June 9, 2011