Addition of Intramuscular Epinephrine to Standard of Care by Paramedics to Decrease Time-to-Initial Epinephrine Dose in Pediatric Out-of-Hospital Cardiac Arrest: A Simulation Trial.

Objectives: Survival rates for pediatric out-of-hospital cardiac arrest (POHCA) are low at around 10%. Paramedic services administer critical interventions including epinephrine. While typically administered via intravenous (IV) or intraosseous (IO) routes, obtaining these access points in out-of-hospital emergencies is challenging. We aimed to evaluate the time to first dose epinephrine and dosing accuracy in a simulated POHCA event.

Methods: Paramedics were randomized to one of three epinephrine administration routes: 1) IV or IO; 2) intramuscular (IM) by autoinjector; or 3) IM by needle/syringe. Each participant was asked to provide resuscitation to a school-aged mannequin with asystole, including administration of epinephrine via their randomized route. Participants were not directly informed of the outcome variables. The primary outcome was time to initial epinephrine dose for each route. Our secondary outcomes were non-inferiority time to definitive dose epinephrine (i.e., by IV or IO), time to secure vascular access (either IO or IV), and administration of correct epinephrine dose (within 20% of correct dose).

Results: Sixty six paramedics participated. We demonstrated a significant reduction in time to initial dose of epinephrine of 1.5 min (p < 0.001) by the IM route using epinephrine autoinjectors compared to standard of care by IV or IO. We also demonstrated that using a needle and syringe to administer epinephrine by the IM route offered no benefit in time to initial epinephrine dose and led to more dosing errors for the definitive dose of epinephrine (i.e., by IV or IO) (n = 4). We demonstrated that time to secure vascular access after IM injection with an auto-injector was delayed by 1:07 min (p = 0.002) compared to IV/IO.

Conclusions: This is the first study to demonstrate that IM epinephrine by autoinjector is feasible in a simulated POHCA scenario and confers a significant advantage in time to initial dose of epinephrine. This study will inform future human trials of IM epinephrine for POHCA.