Written by Amanda Mathews
In this systematic review and meta-analysis, researchers found that epinephrine in standard doses, high doses, and with vasopressin lead to an improvement in ROSC and survival to hospital admission in out-of-hospital cardiac arrest (OHCA) but did not improve survival to discharge or functional neurologic outcome.
Why does this matter?
Epinephrine is part of American Heart Association guidelines for the treatment of cardiac arrest, but the PARAMEDIC-2 trial showed that epinephrine improved ROSC but not long term functional outcome. Use of epinephrine has been a point of controversy for over 100 years. We covered an epinephrine meta-analysis back in 2019, which showed improved ROSC and survival – though not with favorable neurological outcome. What does this even larger meta-analysis find?
More Epi, more problems?
This was a large systematic review and meta-analysis of 18 randomized control trials (21,594 patients) that included patients aged 16 or older with non-traumatic OHCA who received intravenous medication or placebo. They excluded studies that included medications delivered IM or via endotracheal tube. The researchers included studies that evaluated the efficacy of standard dose epinephrine (1mg or 0.01-0.02 mg/kg), high dose epinephrine (single dose > 5mg or 0.1mg/kg), a combination of standard dose epinephrine and vasopressin, or vasopressin alone compared to each other or a placebo. They conducted separate subgroup analyses comparing outcomes in patients with an initial shockable rhythm versus non-shockable rhythm.
This study found that all medication interventions compared to placebo improved ROSC and patient survival to hospital admission but did not lead to an improvement in hospital discharge or survival with good functional outcome. There was no difference in patient centered outcomes when comparing standard dose epinephrine and high dose epinephrine. Survival to hospital discharge was improved in the non-shockable rhythm subgroup but was not improved in the shockable rhythm subgroup with the administration of standard dosing epinephrine.
Overall, this study supports the current recommendation for 1mg epinephrine dosing in non-shockable OHCA. For shockable rhythms, shock first before trying 1mg epinephrine. This study does not find any role for vasopressin in the treatment of OHCA.
Epinephrine in Out-of-Hospital Cardiac Arrest: A Network Meta-analysis and Subgroup Analyses of Shockable and Nonshockable Rhythms. Chest. 2023 Jan 31:S0012-3692(23)00165-4. doi: 10.1016/j.chest.2023.01.033. Epub ahead of print.