Search

Hemodynamic effects of dobutamine and dopamine (both 5, 10, 15 microgram/kg/min) and epinephrine (0.04 microgram/kg/min) were studied immediately following cessation of cardiopulmonary bypass in 34 patients with preoperative evidence of left ventricular dysfunction. Significant increases in mean cardiac index were seen with dobutamine (15, 25, and 26% respectively), and epinephrine (30%). The largest increases occurred with dopamine (44, 53, and 64 percent respectively). Responses varied from patient to patient, however. Seven patients developed marked output increases without concomitant increases in arterial pressure, whereas seven others showed "satisfying" increases in arterial pressure without appreciable output increases. Heart rate increases were small and few arrhythmias were noted. We conclude that dopamine, epinephrine, and dobutamine all are effective inotropic agents during the immediate post-bypass period, with variations discussed in detail. None possess the disturbing chronotropic and arrhythmogenic effects of isoproterenol (previously studied). Efficacy of administration of inotropic drugs seems best assessed by serial output measurements during this period.

Dobutamine, a recently introduced derivative of dopamine, is reported to retain inotropic properties with less pronounced chronotropic and arrhythmogenic effects than isoproterenol. The drug was evaluated in two doses, 5 mug/kg/min and 10 mug/kg/min, in two groups of ten patients each, during emergence from cardiopulmonary bypass. A third group of five patients was studied similarly with isoproterenol, 0.02 mug/kg/min. Cardiac index increased 16 and 28 per cent eith the two doses of dobutamine, respectively, and 9 per cent with isoproterenol. Heart rate, in contrast, increased 6 and 15 per cent with dobutamine (not significant) and 44 per cent with isoproterenol (significant). Dobutamine seemed to associated with fewer arrhythmias than isoproterenol. It is concluded that dobutamine, 5-10 mug/kg/min, is suitable for use during emergence from cardiopulmonary bypass and may possess advantages over isoproterenol.

Almost three decades have passed since the establishment of open-heart surgery, and in such a short life span the specialty has established itself scientifically and reached a certain maturity. New techniques, better understanding of the pathophysiology of cardiac problems, and the effective use of new drugs constantly improve the results of operation. Greater experience in anesthetic management and improved postoperative care will contribute much to the success of this youngest surgical specialty. This review outlines the current principles of anesthesia and postoperative care of patients undergoing cardiac operations. Preanesthetic evaluation provides guidance for anesthetic management, supportive techniques, and postoperative care. During operations, light anesthesia is usually sufficient for patients with cardiac disease and minimizes myocardial depression. Monitoring must provide data on the physiological changes that are taking place from moment to moment during and after operations. Perfusion produces a highly abnormal state, and the severity of complications varies with its duration. Introduction of new drugs has also facilitated hemodynamic management during and after operations. Postoperative care is based on careful observation of the patient and early detection of trends, both of which lead to preventive rather than curative treatment wheneven possible.