Neil H. Winawer, MD, SFHM, reviewing
For patients with shockable rhythms, receiving epinephrine prior to defibrillation resulted in worse outcomes.
For patients with shockable rhythms (i.e., ventricular fibrillation or pulseless ventricular tachycardia), guidelines recommend epinephrine only after several refractory defibrillation attempts. However, epinephrine frequently is administered inappropriately prior to the first or second defibrillation attempt. To determine the effect of epinephrine when it is administered for shockable rhythms prior to initial defibrillation, researchers retrospectively identified 35,000 patients — hospitalized at 500 U.S. hospitals between 2000 and 2018 — with in-hospital arrest due to ventricular fibrillation or pulseless ventricular tachycardia. Epinephrine was given before defibrillation in 28% of patients. About 9000 patients who received epinephrine before defibrillation were compared with 9000 propensity-matched patients who did not receive epinephrine.
Patients who received epinephrine before defibrillation were significantly less likely to survive to hospital discharge (25% vs. 30%) or to survive to discharge with favorable neurological outcomes (19% vs. 21%). The median time to defibrillation was 3 minutes in the epinephrine group and 0 minutes in the no-epinephrine group. The negative association of epinephrine with survival persisted even after matching according to defibrillation time.
Despite guidelines recommending prompt defibrillation in patients with shockable rhythms, more than a quarter of inpatients inappropriately received epinephrine prior to defibrillation. This might be due to delays in assessing the rhythm or the assumption of asystole or pulseless electrical activity — rhythms that occur in >85% of cardiac arrests and for which epinephrine is the initial treatment of choice. Understanding the underlying factors behind these findings is critical in designing interventions that ensure best practices during cardiopulmonary resuscitation.
Evans E et al. Epinephrine before defibrillation in patients with shockable in-hospital cardiac arrest: Propensity matched analysis. BMJ 2021 Nov 10; 375:e066534. (https://doi.org/10.1136/bmj-2021-066534. opens in new tab)