Effect of Epinephrine Administration on Neurological Outcomes in Patients with Out-of-Hospital Cardiac Arrest Receiving Bystander Cardiopulmonary Resuscitation.
Prehospital emergency care · 2025-11-18 · Registry study
Abstract
OBJECTIVES: To examine whether bystander cardiopulmonary resuscitation (BCPR) is associated with the time-dependent effects of epinephrine administration on neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients. METHODS: We conducted a retrospective cohort study using the All-Japan Utstein Registry from 2015 to 2019. Witnessed OHCA cases of presumed cardiac origin in patients aged 15-116 years who received epinephrine were included. Patients were stratified by initial cardiac rhythm (shockable or non-shockable) and categorized by time to epinephrine administration into early (0-19 min), intermediate (20-26 min), and late (27-56 min) groups. Multivariable logistic regression was performed to assess the association between BCPR and favorable neurological outcomes (CPC 1-2) at one month, adjusting for potential confounders. An interaction term between BCPR and epinephrine timing was included in the models to evaluate whether BCPR modified the time-dependent association between epinephrine administration and outcomes. RESULTS: Among 31,670 patients, 18.5% had shockable and 81.5% had non-shockable rhythms. In the shockable cohort, BCPR was significantly associated with favorable neurological outcomes overall (AOR 1.86, 95% CI 1.41-2.44), particularly in the early (AOR 1.75, 95% CI 1.30-2.34) and intermediate (AOR 2.84, 95% CI 1.75-4.61) groups. No significant interaction between BCPR and epinephrine timing was observed in this cohort. In the non-shockable cohort, BCPR was not independently associated with favorable outcomes across any time category. However, the interaction analysis indicated that the time-dependent effect of epinephrine differed slightly according to BCPR status (AOR for interaction 1.03, 95% CI 1.00-1.05, p = 0.03). CONCLUSIONS: In shockable OHCA, BCPR was associated with improved outcomes, but no significant interaction with epinephrine timing was observed. In non-shockable OHCA, BCPR itself was not associated with outcomes, while the interaction analysis suggested a possible difference by BCPR status, indicating that the functional role of BCPR may vary depending on the initial rhythm.