Effect of prehospital epinephrine on out-of-hospital cardiac arrest: a report from the national out-of-hospital cardiac arrest data registry in Japan, 2011-2012.

PURPOSE: The effect of prehospital epinephrine on neurological outcome in out-of-hospital cardiac arrest (OHCA) is still controversial. We sought to determine whether prehospital epinephrine administration was associated with improved outcomes in adult OHCA.

METHODS: A nationwide, population-based, propensity score-matched study of OHCA patients from January 1, 2011, to December 31, 2012, in Japan was conducted. We included adult OHCA patients treated by emergency medical service personnel without an excessive delay. The primary outcome was neurologically favorable survival 1 month after OHCA.

RESULTS: A total of 237,068 patients (16,616 with a shockable rhythm and 220,452 with a non-shockable rhythm) were included in the final cohort. A total of 4024 out of the 16,616 shockable OHCAs and 29,393 out of the 220,452 non-shockable OHCAs received prehospital epinephrine. In the propensity score-matched cohort, prehospital epinephrine was associated with a decreased chance of neurologically favorable survival (shockable OHCA 7.6 vs. 17.9 %, OR 0.38 [95%CI 0.33-0.43]; non-shockable OHCA 0.6 vs. 1.2 %, OR 0.47 [95%CI 0.39-0.56]). In the subgroup analyses, prehospital epinephrine was significantly associated with poor neurological outcome in all subgroups. In the ancillary analyses, although the neurological outcome was worse as the number of epinephrine doses increased or the time to epinephrine increased, patients had a greater chance of a favorable neurological outcome only when a single dose of epinephrine was administered within 15 min of the emergency call in shockable OHCA.

CONCLUSIONS: Among adult OHCA patients, prehospital epinephrine was associated with a decreased chance of neurologically favorable survival. Situations in which prehospital epinephrine is effective may be extremely limited.