Adrenaline for out of hospital cardiac arrest?

In a linked article (doi:10.1136/bmj.f6829), Nakahara and colleagues from Japan write another chapter in the long running saga of the administration of adrenaline (epinephrine) during cardiac arrest.1 Despite being in widespread use for decades, no one has proved that adrenaline improves neurologically intact survival after cardiac arrest, although this observational propensity matched analysis might be the closest yet. The authors show that patients who received adrenaline during a cardiac arrest outside of hospital had a significantly better chance of survival to hospital discharge than matched controls who received no adrenaline. However, no meaningful difference was seen in overall neurologically intact survival.

Two randomised controlled trials have previously tried to determine a causal association between adrenaline and survival after out of hospital cardiac arrest, but both had limitations. The first study was designed to test the hypothesis that intravenous drug administration would lead to inferior quality of cardiopulmonary resuscitation and thereby inferior outcome.2 This hypothesis could not be confirmed because both arms of the study had good quality cardiopulmonary resuscitation and the study was not powered to detect small differences in survival …