Dopamine versus Dobutamine after Open‐Heart Surgery

Abstract

The haemodynamic effects of dopamine and dobutamine were compared in a cross-over study of 12 patients in the early postoperative phase after open-heart surgery. The drug infusion rates (dopamine (microgram/kg/min) mean 6.5, range 2.8-12, dobutamine (microgram/kg/min) mean 7.9, range 4.3-12.3) were adjusted so that the cardiac output increased by 50%. With both drugs this was achieved through simultaneous increases in stroke volume (dopamine + 16%, dobutamine + 9%) and heart rate (dopamine + 31%, dobutamine + 38%). The systemic vascular resistance did not change with dopamine but decreased significantly (-18%) with dobutamine. Therefore, the systolic and diastolic arterial blood pressures rose significantly more with dopamine than with dobutamine. The left atrial pressure increased with dopamine but was unchanged with dobutamine. The urine output was significantly higher with dopamine than with dobutamine.

Use of Enoximone in Weaning from Cardiopulmonary Bypass following Mitral Valve Surgery

“…This may be a consequence of periopera tive myocardial ischaemia or necrosis, either alone or in combination with advanced pre operative myocardial dysfunction. In addi tion, some of these patients have pre-exist ing pulmonary hypertension which, though it may have an element of reversibility, ren ders them liable to right ventricular failure [2], Conventional inotropes, even dobutamine [3], all tend to increase pulmonary vascu lar resistance. Conventional management in weaning from cardiopulmonary bypass in cludes optimization of filling pressures, ad ministration of adrenergic agents, some times in combination with vasodilators, such as glyceryl trinitrate [4,5], in an at tempt to minimize increases in pulmonary vascular resistance, and in some cases me chanical support with balloon counterpulsa tion [6,7] or ventricular assist devices, either univentricular [8] or biventricular [9] as required.…”