Resusc Plus. 2025 Oct 20;26:101140. doi: 10.1016/j.resplu.2025.101140. eCollection 2025 Nov.

INTRODUCTION: Adrenaline provides inotropic, chronotropic and vasopressor effects and is a cornerstone drug during cardiopulmonary resuscitation. This study of in-hospital cardiac arrest aimed to investigate the effect of adrenaline on the return of spontaneous circulation (ROSC) in primary pulseless electrical activity (PEA).

METHOD: In-hospital cardiac arrests episodes at St. Olav University Hospital (Norway) were prospectively registered between 2018 and 2022, among these were 73 episodes with primary PEA. Time of adrenaline administration was obtained with minutes precision by reviewing the clinical record and interviewing personnel, thereby establishing a consistent timeline. We investigated transitions from primary PEA to ROSC following adrenaline administration using time-to-event models.

RESULTS: Adrenaline exerted its maximum effect between 45 and 85 s after administration and strongly favored the transition from primary PEA to ROSC, with an intensity ratio of 5.03 (p < 0.001). Repeated doses of adrenaline, however, had no effect in case of absence of an initial response. Basic life support alone yielded a transition intensity from primary PEA to ROSC of about 0.06, i.e., 6 % per minute.

CONCLUSION: We found a rapid and five-fold increase in the transition intensity from primary PEA to ROSC approximately one minute after adrenaline administration. Repeated doses in the absence of an initial response did not alone increase the transition probability.

PubMed:41323241 | PMC:PMC12662075 | DOI:10.1016/j.resplu.2025.101140