COMPARISON OF THE HEMODYNAMIC-EFFECTS OF DOBUTAMINE WITH ENOXIMONE AFTER OPEN-HEART-SURGERY IN SMALL CHILDREN

We have studied 28 children (mean age 13.6 months) undergoing elective cardiac surgery involving a myocardial ischaemic time greater than 60 min. Thirteen received phenoxybenzamine I mg kg(-1) before cardiopulm onary bypass (CPB) and dobutamine 10 mu g kg(-1) min(-1) before discon tinuation of CPB; 15 received enoximone 0.5 mg kg(-1) followed by an i nfusion of 10 mu g kg(-1) min(-1) before discontinuation of CPB. Haemo dynamic variables were measured at intervals for 6h after CPB. Two pat ients in each group required additional inotropic support with adrenal ine. Heart rates, right and left atrial pressures, mean pulmonary arte ry pressures and systemic and pulmonary vascular resistance indices we re similar in the two groups. Mean arterial pressure was significantly greater in those receiving dobutamine (61.3 (SD 7.6) mm Hg) compared with enoximone (56.2 (5.3) mm Hg) (P < 0.05). Differences in cardiac i ndex (thermodilution) (dobutamine group 2.92 (0.62) litre min(-1) m(-2 ); enoximone group 2.55 (0.55) litre min(-1) m(-2)) and left ventricul ar stroke work index (dobutamine group 13.1 (4.7) g m beat(-1) m(-2); enoximone group 10.4 (2.7) g m beat(-1) m(-2)) were not statistically significant. Enoximone may be used successfully in these patients to a ssist discontinuation of CPB and maintain an acceptable haemodynamic s tate in the early postoperative period but, when used alone, conferred no advantage compared with the combination of dobutamine and phenoxyb enzamine.