Potential risks of high-dose epinephrine for resuscitation from ventricular fibrillation in a porcine model.

The arterial plasma concentrations and hemodynamic effects of epinephrine, 10 micrograms/kg, IV (group A, N = 8) and 50 micrograms/kg, IV (group B, N = 8) were compared in a porcine resuscitation model after 3 minutes of circulatory arrest induced by ventricular fibrillation. All animals in group A were successfully resuscitated after 4.9 +/- 2.8 minutes and 2.8 +/- 1.6 defibrillations. In group B, only 6 of 8 animals were successfully resuscitated after 6.3 +/- 1.1 minutes and 4.0 +/- 2.7 defibrillations (mean +/- SD). During CPR, cardiac output (CO), left ventricular systolic pressure (LVSP), and mean arterial pressure (MAP) were nearly identical in the groups. The hemodynamic situation during the first hour after restitution of spontaneous circulation in group B was characterized by a significantly higher heart rate, combined with significantly lower values for cardiac inotropy, CO, LVSP, and MAP compared to group A. Mean arterial peak epinephrine concentrations (group A 197 +/- 133 ng/mL, group B 1173 +/- 298 ng/mL) were approximately fivefold higher in group B. After resuscitation, plasma concentrations returned to baseline levels within 7 minutes in group A and 15 minutes in group B. Later hemodynamic differences between the groups are thereby attributed to a detrimental impact of high-dose epinephrine on the heart during resuscitation.