Epinephrine in Prehospital Traumatic Cardiac Arrest-Life Saving or False Hope?

Objectives: While epinephrine is widely used for medical cardiac arrests, there is a knowledge gap regarding its utility for traumatic arrests. Traumatic arrests result from hypovolemia, hypoxia, or anatomic impairment of cardiac function such that the inotropic and vasoconstrictive effects of epinephrine may be ineffective or harmful. We hypothesized that epinephrine does not improve survival among patients with traumatic cardiac arrest.

Methods: This was a multicenter retrospective cohort study of trauma patients sustaining prehospital cardiac arrest who were treated at seven level I and II trauma centers over 6 years (2011-2017), ascertained via trauma registry data and chart abstraction. The primary outcome was survival to hospital discharge; patients treated with or without epinephrine were compared. Multivariable analyses were performed using Poisson regression. Time to event analyses were conducted using Cox proportional hazard models.

Results: We included 1631 adult and pediatric trauma patients with prehospital cardiac arrest. Prehospital epinephrine was administered to 844 (52%). The median age was 35 years, 335 (21%) were female, 712 (44%) sustained blunt trauma, and 58 (4%) had a shockable initial rhythm. Survival to hospital discharge was significantly lower in the prehospital epinephrine cohort compared to the no epinephrine cohort in univariable analysis [43/844 (5%) vs. 125/787 (16%), p < 0.001]. Among patients with blunt mechanism, survival was significantly lower in the prehospital epinephrine cohort [12/382 (3%) vs. 54/330 (16%), p < 0.001]. Among patients with penetrating mechanism, survival was not statistically different [10/276 (4%) with epinephrine vs. 22/374 (6%) without, p = 0.19]. In multivariable analyses adjusting for age, sex, mechanism, and initial rhythm, epinephrine was associated with lower likelihood of survival in the overall and blunt cohorts; there was no significant difference in the penetrating cohort (overall aRR 0.33, 95% CI 0.23-0.46; blunt aRR 0.20, 95% CI 0.11-0.37; penetrating aRR 0.62, 95% CI 0.30-1.28). Adjusted and unadjusted time to event analyses across each of these cohorts showed that epinephrine was associated with either statistically inferior or indistinct hazard ratios.

Conclusions: Epinephrine was not associated with improved survival following traumatic cardiac arrest, and in multiple subanalyses, it was associated with inferior outcomes. These results may inform prehospital traumatic arrest protocols.