Feasibility and Efficacy of Prehospital Esmolol for Refractory Ventricular Fibrillation

Abstract Background: We aimed to assess the feasibility of prehospital bolus dose esmolol for patients with out-of-hospital cardiac arrest (OHCA) and refractory ventricular fibrillation (RVF) treated by a single, high-volume, ground-based emergency medical services (EMS) agency. Methods: This retrospective observational study evaluated EMS patients with RVF treated from June 10, 2017 to June 10, 2020. Esmolol (0.5mg/kg bolus) was added to the RVF protocol at the mid-point of the study period on December 10, 2018. Results: We analyzed 61 patients treated with prehospital esmolol and 63 patients treated without esmolol. Median time from EMS arrival to esmolol administration was 17 minutes (interquartile range: 13-22 minutes). Prehospital return of spontaneous circulation (ROSC) was higher in the esmolol group compared to the control group, though statistical significance was not reached (38% versus 24%, p=0.09). Overall, few patients survived to 24 hours (esmolol n=15, pre-esmolol n=16) and fewer survived to hospital discharge (esmolol n=5, pre-esmolol n=5), precluding stable statistical comparisons. Conclusion: Our findings suggest that esmolol is feasible in the prehospital setting and may lead to increased ROSC. Further large-scale studies are needed to determine the effect of prehospital esmolol for RVF as it relates to survival to hospital discharge.Trial Registration: This study was approved by the institutional review board at The Baylor College of Medicine and a waiver of informed consent was granted - protocol number H-48383.