Early administration of adrenaline is associated with improved survival after out-of- hospital cardiac arrest (OHCA). Delaysin vascular access may impact the timely delivery of adrenaline. Novel methods for administering adrenaline before vascular access may enhance survival. The objective of this study was to determine whether an initial intramuscular (IM) adrenaline dose followed by standard IV/IO adrenaline is associated with improved survival after OHCA.