THE HEMODYNAMIC-EFFECT OF PROPHYLACTIC PERIOPERATIVE 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 dopex amine hydrochloride on haemodynamic indices and peripheral perfusion. The infusion commenced following induction of anaesthesia and continue d for 24 h postoperatively. The study demonstrated that dopexamine sig nificantly increased cardiac index compared with the control group (P< 0.05) and that this effect was mediated through an increase in both le ft ventricular stroke volume index and heart rate (P<0.05). This was a ssociated 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 funct ion, both groups exhibited a fall in pH (P<0.05) relative to baseline levels. This fall in pH began prior to cardiopulmonary bypass and pers isted in the early postoperative period in both groups, suggestive of tissue hypoperfusion and oxygen deficiency. These indices normalized m ore rapidly in the dopexamine group, suggesting a more rapid reversal of an intra-operative oxygen debt in this group. The study demonstrate s the mechanism of action of dopexamine on cardiac function and periph eral perfusion during cardiac surgery and shows that the inodilator pr operties during cardiac surgery are useful haemodynamically and facili tate early reversal of tissue hypoperfusion and oxygen debt in this en vironment.