Epinephrine vs. Defibrillation: Does Operational Order Matter in Out-of-Hospital Cardiac Arrest?

Introduction—The administration of both vasopressors and defibrillation has been shown to increase the rate of return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA).

Objective—To determine the significance of operational order (the first chronological intervention of either a vasopressor or defibrillation) of vasopressors and defibrillation in OHCA.

Methods—A retrospective study of OHCA patients was conducted using data from the Prehospital Medical Information System (PreMIS) from Jan. 1, 2012, to June 30, 2014. Included were adult patients with a witnessed arrest who presented in a shockable rhythm. Patients were excluded if the etiology of their arrest was drowning, electrocution, trauma, or unknown. A chi-square test was used to evaluate the direct relationship between operational order and ROSC. A logistic regression was used to identify predictors of ROSC after controlling for confounders.

Results—A total of 736 patients were evaluated within the studied timeframe. Of those, 556 patients (75.5%) were male, 164 patients (22.3%) were minorities, and mean age was 62.79 (±14.29) years. ROSC occurred in 401 patients (54.5%), and 352 patients (47.8%) received lay person CPR. A total of 181 patients (24.9%) received a vasopressor first. A chi-square of the relationship between the operational order of first-line treatment and the influence on ROSC was not significant (p=0.239). A logistic regression model showed operational order was not significant (OR 0.836, p=0.31) when controlling for other OHCA-related factors.

Conclusion—No significant relationship existed between the operational order of first-line treatment and ROSC. A higher-than-expected proportion of patients in the sample received vasopressors as the first-line treatment despite best practice-based protocols as determined by the American Heart Association.