Continued circulatory support: effect of epinephrine or dopamine on 24-hour survival and neurologic function in dogs

The effects on 24-h survival and neurologic function were compared following continued postresuscitation circulatory support with epinephrine or dopamine. Cardiopulmonary arrest was induced by ventricular fibrillation. After 10 min, resuscitation efforts were initiated including i.v. infusion of either epinephrine (6 μg/kg per min, 11 dogs) or dopamine (10 μg/kg per min, 14 dogs) for continued circulatory support. There was no difference detected in duration of circulatory support, although dogs receiving epinephrine required more lidocaine (3.3 ± 0.4 vs. 1.8 ± 0.3 mg/kg, P = 0.005). Likewise, there was no statistically significant difference detected in MAP or HR between groups at any time tested. However, dogs receiving epinephrine had significantly worse neurologic function at 6 and 12 h postarrest. Mean survival time (20.3 ± 1.2 vs. 15.3 ± 1.9 h, P = 0.028) and overall survival (P = 0.027, survival curve analysis) were significantly longer for dogs receiving dopamine. Plasma glucose in the first 6 h postarrest was significantly higher in dogs receiving epinephrine (P = 0.006). These results suggest that the use of epinephrine for continued vasopressor support in cardiopulmonary resuscitation may contribute to decreased survival and poorer neurologic function in this controlled experimental setting. It is reasonable to propose that similar responses to these commonly used circulatory support agents occur clinically. Therefore, continued vasopressor support with dopamine rather than epinephrine may be justified in the setting of cardiac resuscitation.