Timing of Intravenous Epinephrine Administration During Out-of-Hospital Cardiac Arrest

Background: Current guidelines for cardiopulmonary resuscitation recommend that standard dose of epinephrine be administered every 3 to 5 min during cardiac arrest. However, there is controversy about the association between timing of epinephrine administration and outcomes after out-of-hospital cardiac arrest (OHCA). This study aimed to determine whether the timing of intravenous epinephrine administration is associated with outcomes after OHCA. Methods: We analyzed Japanese government-led nationwide population-based registry data for OHCA. Adult OHCA patients who received intravenous epinephrine by emergency medical service personnel in the prehospital setting from 2011 to 2017 were included. Multivariable logistic regression models were used to assess the associations between time to first epinephrine administration and outcomes after OHCA. Subsequently, associations between early (<= 20 min) versus delayed (>20 min) epinephrine administration and outcomes after OHCA were examined using propensity score-matched analyses. The primary outcome was 1-month neurologically favorable survival. Results: A total of 119,946 patients (mean [SD] age, 75.2 [14.8] years; 61.4% male) were included. The median time to epinephrine was 23 min (interquartile range, 19-29). Longer time to epinephrine was significantly associated with a decreased chance of 1-month neurologically favorable survival (multivariable adjusted OR per minute delay, 0.91 [95% CI, 0.90-0.92]). In the propensity score-matched cohort, when compared with early (<= 20 min) epinephrine, delayed (>20 min) epinephrine was associated with a decreased chance of 1-month neurologically favorable survival (959/42,804 [2.2%] vs. 330/42,804 [0.8%]; RR, 0.34; 95% CI, 0.30-0.39; NNT, 69). Conclusions: Delay in epinephrine administration was associated with a decreased chance of 1-month neurologically favorable survival among patients with OHCA.