Epinephrine Before Defibrillation In Cardiac Arrest Linked To Poor Outcomes

Saket Girotra, MD

Although guidelines prioritize immediate defibrillation for in-hospital cardiac arrest, more than 1 in 4 patients are treated with epinephrine before defibrillation, according to a recent study.

Led by Saket Girotra, MD, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, a team of investigators used data from the Get With The Guidelines-Resuscitation (HWTG-R) registry of in-hospital cardiac arrest in the United States.

They examined both frequency of use of epinephrine before first defibrillation in patients with a shockable in-hospital cardiac arrest and the association of epinephrine before defibrillation with survival to discharge.

Girotra and colleagues used the 2000 - 2018 data from the GWTG-R registry, including adults aged ≥18 years with an index in-hospital cardiac arrest due to initial shockable rhythm treated with defibrillation.

They identified 51,557 patients that met this criteria. Following exclusions for in-hospital cardiac arrest in the emergency department or did not receive defibrillation or epinephrine, the final cohort consisted of 34,820 patients at 497 hospitals.

Primary exposure was administration of epinephrine before first defibrillation, while the primary outcome was survival to discharge. They also examined neurological disability using cerebral performance category scores, with a score of 1 denoting mild or no neurological disability, 3 designating severe neurological disability, and 5 denoting brain death.

Then, investigators performed a time dependent, propensity matched analysis to adjust for confounding due to indication and evaluate the independent association of epinephrine before defibrillation with study outcomes.

Out of a total of 34,820 patients with an initial shockable rhythm, 9630 (27.6%) were treated with epinephrine before defibrillation. Data show those patients who are more likely to be Black, have renal insufficiency, respiratory insufficiency, or sepsis, but they were less likely to have myocardial infarction during admission to hospital, in comparison to those treated with defibrillation first (P <.0001).

They noted the median time to defibrillation was 1 minute, considered longer in the epinephrine first group compared to the defibrillation first group (median 3 minutes versus 0 minutes).

Data show 14,520 patients (41.7%) survived to hospital discharge, 11,595 (33.3%) had favorable neurological survival, and 26,602 (76.4%) survived after acute resuscitation.

Then, in propensity matched analysis with a total of 18,022 patients (9011 matched pairs), epinephrine before defibrillation was associated with lower odds of survival to discharge (25.2% versus 29.9%, adjusted odds ratio 0.81, 95% CI, 0.74 - 0.88, P <.001), favorable neurological survival (18.6% versus 21.4%, aOR, 0.85, 0.76 - 0.92, P <.001), and survival after acute resuscitation (64.4% versus 69.4%; aOR, 0.76, 0.70 - 0.83, P <.001).

“The above associations were consistent across a range of sensitivity analyses, including analyses in which patients were matched according to defibrillation time, which suggests that the association of epinephrine before defibrillation with study outcomes was not entirely explained by delayed defibrillation in patients who were treated with epinephrine first,” investigators wrote.

The study, “Epinephrine before defibrillation in patients with shockable in-hospital cardiac arrest: propensity matched analysis,” was published online in the BMJ.