Abstract 138: Epinephrine Before Defibrillation In Adults With Shockable Rhythm Out-of-hospital Cardiac Arrest

Introduction: Guidelines recommend epinephrine treatment after the first defibrillation in the resuscitation of patients with shockable rhythm cardiac arrest. Degrees to which routine practice adheres to clinical guidelines can be variable. Hypothesis: Epinephrine was administered prior to defibrillation in a non-trivial proportion of patients with shockable rhythm out-of-hospital cardiac arrest (OHCA). Such practice is associated with worse outcomes. Methods: We conducted a retrospective study in a North American OHCA epidemiologic registry between 2011 and 2015. We assessed the proportion of participants with shockable rhythm OHCA who received pre-defibrillation epinephrine and described their characteristics. In a propensity-matched cohort, we used logistic regression to evaluate associations between pre-defibrillation epinephrine and outcomes, i.e., pre-hospital return of spontaneous circulation (ROSC), survival to hospital discharge, and favorable neurological outcome (modified Rankin Scale score ≤3) at discharge. Results: Of 6938 individuals with shockable rhythm OHCA, 522 (7.5%) received epinephrine before defibrillation. Comparing these patients to those who did not receive pre-defibrillation epinephrine, mean time from emergency medical services activation to first defibrillation was longer (17.5 vs 10.5 min) and a greater proportion received epinephrine intra-osseously (24 vs 20%). In total, 392 (75%) and 5119 (80%) gained prehospital ROSC, 78 (15%) and 1237 (19%) survived to hospital discharge, and 48 (9%) and 996 (16%) had favorable functional outcome at discharge respectively. In propensity-matched analysis, epinephrine use prior to defibrillation was associated with statistically insignificant increases in odds of prehospital ROSC (OR=1.20, 95%CI 0.89-1.61; p=0.23), survival (OR=1.46, 95%CI 0.98-2.17; p=0.06), and favorable neurological outcome at hospital discharge (OR=1.21, 95%CI 0.76-1.93; p=0.43). Conclusions: Data from a North American OHCA registry found that epinephrine can be administered prior to defibrillation in up to 7.5% of patients with shockable rhythm cardiac arrest. Such approach was not associated with worse outcomes in propensity-matched analysis.