HEMODYNAMIC-EFFECTS AND COMPARISON OF ENOXIMONE, DOBUTAMINE AND DOPAMINE FOLLOWING MITRAL-VALVE SURGERY

Mitral valve surgery may be complicated by a postoperative low output state requiring inotropic support, and a wide variety of factors may i nfluence the choice of agents used to treat this condition. The author s have examined and compared the haemodynamic effects of the highly sp ecific phosphodiesterase inhibitor enoximone, and the adrenergic agent s dobutamine and dopamine in patients undergoing mitral valve surgery. Enoximone, 0.5 mg kg-1 bolus, followed by a continuous infusion of 5 mug kg-1min-1, was compared against dobutamine, 7 mug kg-1min-1, and d opamine, 5 mug kg-1min-1, with the protocol allowing for an increase i n the infusion rate by a factor of two if clinical and haemodynamic me asurements indicated. All 25 patients receiving enoximone were success fully weaned from cardiopulmonary bypass at the first attempt, with si gnificant increases in cardiac index and stroke index, combined with l ittle or no change in heart rate or pulmonary artery pressures and a h ighly significant reduction in systemic vascular resistance, and a red uction in mean arterial pressure. Three of the 25 patients receiving d obutamine were withdrawn from the study because of inadequate haemodyn amic response, while the remaining 22 patients demonstrated significan t increases in heart rate, cardiac index and stroke index, with a redu ction in systemic vascular resistance. Nine of the 25 patients receivi ng dopamine failed to respond adequately, while the remaining 16 demon strated an increase in heart rate and cardiac index but with little ch ange in stroke index and a modest reduction in systemic vascular resis tance. Enoximone has been shown to be a highly effective first-line in otrope in patients following mitral valve surgery with significant adv antages over dobutamine and dopamine.