Prehospital Epinephrine Appears to Increase Return of Spontaneous Circulation but Decrease 1-Month Survival in Patients with Out-of-Hospital Cardiac Arrest

Epinephrine is a common and accepted element of early treatment for patients with out-of-hospital cardiac arrest, and it is part of the standard treatment algorithm for both shockable and non-shockable rhythms recommended by the American Heart Association (Circulation 2010 Nov 2;122(18 Suppl):S640). Epinephrine increases coronary perfusion pressure during resuscitation, and this increase in coronary blood flow is believed to increase the likelihood of successfully resuscitating the heart. However, despite being in widespread use since the 1960s, the efficacy of epinephrine has rarely been investigated. A new large cohort study conducted in Japan calls current recommendations into question, suggesting that prehospital epinephrine treatment may be harmful.

A total of 417,188 patients (mean age 72 years) with out-of-hospital cardiac arrest from 2005 to 2008 were included in the study. All patients had cardiac arrest before the arrival of emergency medical services, were treated by emergency medical personnel, and were then transported to the hospital. Of this group, 15,030 patients (3.6%) were treated with IV epinephrine prior to hospital arrival.

The investigators used a propensity analysis to control for confounding factors and selection bias. For each patient, a propensity score based on demographic and clinical factors was calculated to estimate the probability of receiving epinephrine treatment. Demographic factors included age, sex, year of treatment, and presence of bystander or family member eyewitnesses. Clinical factors included the etiology of the cardiac arrest, whether resuscitation was attempted by bystanders, makeup of ambulance staff, use of advanced life support, times to ambulance arrival and hospital arrival, type of first documented rhythm, and insertion of an IV line. A subgroup of 26,802 patients (half of these receiving epinephrine) were included in the propensity-matched analysis.

In the propensity-matched cohort, spontaneous circulation returned before hospital arrival in 18.3% of epinephrine-treated patients and 10.5% of nontreated patients (p < 0.001, NNT 13) (level 2 [mid-level] evidence). However, 1-month survival was significantly reduced in the epinephrine group (5.1% vs. 7%, p < 0.001, NNH 52). Survival with good or moderate cerebral performance at 1 month was also reduced for epinephrine (1.3% vs. 3.1%, p < 0.001, NNH 55). Similar results were attained in analyses of the complete cohort (JAMA 2012 Mar 21;307(11):1161). It is important to note that this study looked at the effects of epinephrine use in the pre-hospital setting only . These findings should not be considered generalizable to the broader use of epinephrine in situations where more resources for treating all aspects of the patient's condition are available.

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