Association of epinephrine and outcome in cardiac arrest with refractory shockable rhythm: a population-based,...

Epinephrine use in cardiac arrest is increasingly controversial, with contrasting results according to initial rhythm. We assessed the association between epinephrine use and favorable neurological outcome among patients with out of hospital cardiac arrest with refractory shockable arrest.

In this multicentric population-based prospective registry, we included all patients with out-of-hospital cardiac arrest, with persistent ventricular fibrillation after at least 3 defibrillations from 15/05/2011 to 31/12/2021 in Paris and its suburbs. Primary outcome was survival with a favorable neurological outcome (Cerebral Performance Categories level 1 or 2 at hospital discharge). A multivariate logistic regression analysis and a propensity score analysis with adjustment, matching and inverse probability weighting were performed.

Among the 3163 patients with refractory shockable arrest, 2572 (81%) received epinephrine. Primary outcome was achieved in 270 patients (11%) among those who received epinephrine, and in 294 patients (50%) among those who did not. After adjustment, epinephrine use remained negatively associated with favorable outcome (aOR 0.24, 95%CI 0.19-0.31, p < 0.001). This negative association between epinephrine and favorable outcome was consistent after adjustement for propensity-score (aOR 0.24, 95%CI 0.18-0.31, p < 0.001), matching on propensity score (aOR 0.40, 95%CI 0.31-0.51, p < 0.001), and in various sensitivity analyses.

In a large population-based registry of patients experiencing refractory ventricular fibrillation, epinephrine use was consistently associated with worse outcome using various methodological approaches. These findings are challenging the systematic use of epinephrine in refractory ventricular fibrillation.The use of potential alternative therapeutic strategies might be evaluated in this population.