Comparison of Enoximone with Dopamine after Protamine Reversal of Heparin

Abstract

This study compared the effects of enoximone with those of dopamine on myocardial function after protamine administration for the reversal of heparin. Twelve dogs were intubated and given 300 IU/kg heparin. A femoral artery cannula and two venous cannulae were inserted, and the animals were placed on hypothermic (28°C) cardiopulmonary bypass. The hearts were arrested for one hour with cold crystalloid cardioplegic solution and the animals were rewarmed to 36°C. After weaning from bypass, the heparin was neutralized with 4.5 mg/kg protamine sulfate. The dogs were divided into 3 groups: a control group (group C) received only protamine, another group (group D) received dopamine 10 μg/kg/min and protamine, and the third group (group E) received enoximone 10 μg/kg/min and protamine. Cardiac output was 1,320 ± 50 mL/min in group C, 1,420 ± 30 mL/min in group D, and 1,540 ± 10 mL/min in group E. We concluded that enoximone is an effective drug for relieving the adverse effects of protamine on the myocardium.