Epinephrine for cardiac arrest.

PURPOSE OF REVIEW: Epinephrine is the primary drug administered during cardiopulmonary resuscitation (CPR) to reverse cardiac arrest. Epinephrine increases arterial blood pressure and coronary perfusion during CPR via alpha-1-adrenoceptor agonist effects. However, the dose, timing and indications for epinephrine use are based on limited animal data. Recent studies question whether epinephrine provides any overall benefit for patients.

RECENT FINDINGS: A randomized controlled trial indicates that epinephrine for out-of-hospital cardiac arrest increases return of pulses, but does not significantly alter longer-term survival. Very large, well-controlled, observational studies suggest that, despite increases in return of pulses, epinephrine reduces long-term survival and functional recovery after CPR. Detrimental effects were greatest in patients found in ventricular fibrillation. Laboratory data suggest that harmful epinephrine-induced reductions in microvascular blood flow during and after CPR may offset the beneficial epinephrine-induced increase in arterial blood pressure during CPR.

SUMMARY: The available clinical data confirm that epinephrine administration during CPR can increase short-term survival (return of pulses), but point towards either no benefit or even harm of this drug for more patient-centred outcomes (long-term survival or functional recovery). Prospective trials are needed to determine the correct dose, timing and patients for epinephrine in cardiac arrest.