Is epinephrine during cardiac arrest associated with worse outcomes in resuscitated patients?

BACKGROUND: Although epinephrine is essential for successful return of spontaneous circulation (ROSC), the influence of this drug on recovery during the post-cardiac arrest phase is debatable.

OBJECTIVES: This study sought to investigate the relationship between pre-hospital use of epinephrine and functional survival among patients with out-of-hospital cardiac arrest (OHCA) who achieved successful ROSC.

METHODS: We included all patients with OHCA who achieved successful ROSC admitted to a cardiac arrest center from January 2000 to August 2012. Use of epinephrine was coded as yes/no and by dose (none, 1 mg, 2 to 5 mg, >5 mg). A favorable discharge outcome was coded using a Cerebral Performance Category 1 or 2. Analyses incorporated multivariable logistic regression, propensity scoring, and matching methods.

RESULTS: Of the 1,556 eligible patients, 1,134 (73%) received epinephrine; 194 (17%) of these patients had a good outcome versus 255 of 422 patients (63%) in the nontreated group (p < 0.001). This adverse association of epinephrine was observed regardless of length of resuscitation or in-hospital interventions performed. Compared with patients who did not receive epinephrine, the adjusted odds ratio of intact survival was 0.48 (95% confidence interval [CI]: 0.27 to 0.84) for 1 mg of epinephrine, 0.30 (95% CI: 0.20 to 0.47) for 2 to 5 mg of epinephrine, and 0.23 (95% CI: 0.14 to 0.37) for >5 mg of epinephrine. Delayed administration of epinephrine was associated with worse outcome.

CONCLUSIONS: In this large cohort of patients who achieved ROSC, pre-hospital use of epinephrine was consistently associated with a lower chance of survival, an association that showed a dose effect and persisted despite post-resuscitation interventions. These findings suggest that additional studies to determine if and how epinephrine may provide long-term functional survival benefit are needed.