Feasibility of prehospital esmolol for refractory ventricular fibrillation

Esmolol may increase survival for patients with refractory ventricular fibrillation (RVF); however, information related to esmolol use in the prehospital environment is limited. We aimed to assess the feasibility of prehospital bolus dose esmolol for patients with RVF treated by a high-volume, ground-based emergency medical services (EMS) agency.

Esmolol (0.5 mg/kg single bolus) was added to the RVF protocol on December 10, 2018. Feasibility was defined as esmolol administration in >75% of RVF cases. Secondarily, we compared the proportion of patients with prehospital return of spontaneous circulation (ROSC), 24-hour survival, and survival to hospital discharge during the intervention period (December 10, 2018-June 10, 2020) to a historical control period (June 10, 2017-December 9, 2018) using chi-square tests.

Before the protocol change, 63 patients with RVF were identified. After esmolol was added, 70 patients with RVF were identified and 61 (87%) received esmolol. Prehospital ROSC was higher in the esmolol group compared to the historical 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.

Collectively, these findings suggest that EMS clinicians are able to accurately identify RVF and administer esmolol in the prehospital setting and that ROSC may be increased. Further large-scale studies are needed to determine the effect of prehospital esmolol for RVF as it relates to neurologically intact hospital discharge.