HEMODYNAMIC-EFFECTS OF DIFFERENT DOSES OF DOPEXAMINE HYDROCHLORIDE IN LOW CARDIAC-OUTPUT STATES FOLLOWING CARDIAC-SURGERY

We studied the haemodynamic effects of dopexamine hydrochloride, a β2-adrenergic agonist with dopaminergic (DA1) activity, in 20 patients with low cardiac output following surgery for coronary artery bypass grafting and/or valve replacement or repair. Following titration of four doses (1, 2, 4 and 6 μg . kg-1 . min-1), the dose producing the optimal response was infused for up to 48 h (five patients). During the infusion, significant increases in cardiac index and stroke volume were accompanied by significant decreases in systemic vascular resistance. Heart rate increased significantly up to 6 h and thereafter returned to control levels. Mean blood pressure was reduced but did not fall below 60 mmHg. However, in five patients treated for 48 h mean blood pressure had returned to control levels. Unwanted effects (tachycardia and hypotension) were seen chiefly at higher doses, leading us to conclude that infusion rates of 4 μg . kg-1 . min-1 or less will be useful in the treatment of low cardiac output following cardiac surgery. © 1992 The European Society of Cardiology.