The haemodynamic effect of prophylactic peri-operative dopexamine in coronary artery bypass patients.

Twenty-three low risk coronary artery bypass graft patients underwent a controlled study of the effects of prophylactic perioperative dopexamine hydrochloride on haemodynamic indices and peripheral perfusion. The infusion commenced following induction of anaesthesia and continued for 24 h postoperatively. The study demonstrated that dopexamine significantly increased cardiac index compared with the control group (P < 0.05) and that this effect was mediated through an increase in both left ventricular stroke volume index and heart rate (P < 0.05). This was associated with a significantly lower systemic vascular resistance (P < 0.05), without an increase in left ventricular stroke work index in the dopexamine group. Despite normal pre-operative left ventricular function, both groups exhibited a fall in pH (P < 0.05) relative to baseline levels. This fall in pH began prior to cardiopulmonary bypass and persisted in the early postoperative period in both groups, suggestive of tissue hypoperfusion and oxygen deficiency. These indices normalized more rapidly in the dopexamine group, suggesting a more rapid reversal of an intra-operative oxygen debt in this group. The study demonstrates the mechanism of action of dopexamine on cardiac function and peripheral perfusion during cardiac surgery and shows that the inodilator properties during cardiac surgery are useful haemodynamically and facilitate early reversal of tissue hypoperfusion and oxygen debt in this environment.