COMPARISON OF THE HEMODYNAMIC-EFFECTS OF DOPAMINE AND DOBUTAMINE IN YOUNG-CHILDREN UNDERGOING CARDIAC-SURGERY

Nineteen children, aged 2-54 months, requiring high-dose inotropic sup port after cardiac surgery, were given either dopamine or dobutamine i n a blinded, double crossover, study. Using a pulmonary artery thermis tor, right and left atrial cannulae, and pulmonary and femoral arteria l catheters, conventional haemodynamic variables were measured hourly over three consecutive 4 h dopamine-dobutamine-dopamine or dobutamine- dopamine-dobutamine exchanges. No significant differences in haemodyna mics occurred during dopamine therapy compared with the same dose of d obutamine in 14 patients receiving phenoxybenzamine 2 mg kg(-1), four of whom had also received enoximone. In five patients, neither enoximo ne nor phenoxybenzamine was used and significant increases in pulmonar y artery pressure and pulmonary vascular resistance (P=0.04) occurred when patients were given dopamine rather than dobutamine. We conclude that dobutamine and dopamine are equipotent inotropes in children and that dopamine in doses > 7 mu g kg(-1) min(-1), caused pulmonary vasoc onstriction, an effect mediated by cc adrenergic receptors.