The Evolving Role of Esmolol in Management of Pre- Hospital Refractory Ventricular Fibrillation; a Scoping Review

Introduction: Few studies have described their experience using esmolol, an ultra-short acting Κ-adrenergic antagonist, in the emergency department (ED) as a feasible adjuvant therapy for the treatment of refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) out-of-hospital cardiac arrest. However, there is currently insufficient evidence to support the widespread implementation of this therapy. The aim of this scoping review was to summarize the current available evidence on the use of esmolol as an adjuvant therapy for refractory VF/pVT out-of-hospital cardiac arrest, as well as to identify gaps within the literature that may require further research. Methods: We conducted a comprehensive literature search of MEDLINE via PubMed, Embase, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) on July 5, 2019. The search was restricted to articles that were published from January 2000 to July 2019. Google Scholar was searched and reference lists of relevant papers were examined to identify additional studies. We included any controlled clinical study design (randomized controlled trials and non-randomized controlled trials) and observational studies (cohort studies and case-control studies) in adults providing information on the use of esmolol as an adjuvant therapy for refractory VF/pVT out-of-hospital cardiac arrest. Results: The search yielded 2817 unique records, out of which 2 peer-reviewed articles were found relating to the research purpose totaling 66 patients 33.3% (n = 22) of which received esmolol. These studies found that sustained return of spontaneous circulation (ROSC) was significantly more common in the patients that received esmolol compared to the control group. However, no statistically significant outcomes were found regarding survival to discharge and favorable neurological outcome. No randomized controlled trials were identified. Conclusion: To date, it is difficult to conclude the real benefit of esmolol as an adjuvant therapy for refractory VF/pVT out-of-hospital cardiac arrest based on the available evidence. The findings of this scoping review suggest that there is a paucity of research and limited evidence to support this therapy.