Esmolol for Refractory V Fib
The Article: Use of Esmolol after Failure of Standard Cardiopulmonary Resuscitation to Treat Patients with Refractory Ventricular Fibrillation
Driver et al., Resuscitation 85 (2014) 1337–1341.
The Idea: Esmolol may be helpful in refractory ventricular fibrillation by providing unopposed alpha effects when used with epinephrine and by terminating electrical storm that is perpetuated by endogenous and exogenous catecholamines.
This is a retrospective study of 25 patients who had prehospital or ED cardiac arrest with ventricular fibrillation or ventricular tachycardia as their initial rhythm. To be included, patients must have been unresponsive to 3 rounds of defibrillation, 3mg Epinephrine, and at least 300mg of Amiodarone. 6 patients in this study received esmolol (500mcg/kg loading dose, +/- a drip of up to 100mcg/kg/min); 19 patients did not receive esmolol. The Findings:
Comparing the esmolol group to the control group, 67% vs. 42% had temporary return of spontaneous circulation (ROSC); 67% vs. 32% had sustained ROSC; 66% vs. 32% survived to intensive care unit admission; 50% vs. 16% survived to hospital discharge; and 50% vs. 11% survived to discharge with a favorable neurologic outcome. However, the sample sizes were too small to have any statistically significant results, and there were some clinically relevant differences in the demographics and treatment of the two groups (i.e. longer pre-hospital times in no esmolol group), which makes comparison difficult.
The Takeaway: Esmolol can be considered in patients with refractory ventricular fibrillation after standard ACLS has been attempted for at least 3 rounds and has failed. However, due to the small sample size studied and the heterogeneity between the intervention and control groups, the level of evidence in this paper is comparable to a case series, and this paper did not definitively show any effect of treatment with esmolol.