Hemodynamic effects of dexmedetomidine in patients after cardiac surgery

Dexmedetomidine hydrochloride (Prece-dex(R)) is a potent and highly selective central a2-adrenoreceptor agonist. Dexmedetomidine has recently been approved as a new sedative drug, however, its hemodynamic effects on patients just after cardiac surgery has not been established.

Nineteen patients (14 males and 5 females) who underwent elective cardiovascular surgery were included in this study. The mean age of the patients was 65 years. Coronary artery bypass grafting was performed in 8 patients, aortic valve surgery in 5, mitral valve plus radiofrequency Maze surgery in 3, graft replacement of the ascending aorta in 2 and double valve replacement in 1. After surgery, dexmedetomidine was continuously infused for 3 h in total at a rate of 0.8 mg/kg/h for the initial 1 h and followed by 0.4 mg/kg/h.

All patients were well sedated during dexmedetomidine infusion. Dexmedetomidine infusion induced a decrease in systemic blood pressure and systemic vascular resistance index. Heart rate, stroke index, central venous pressure, pulmonary artery pressure and pulmonary artery resistance index remained unchanged. Mixed venous oxygen saturation significantly decreased and arterio-venous O2 content difference increased after the beginning of dexmedetomidine infusion.

Continuous dexmedetomidine infusion did not influence the hemodynamic condition except for the vaso-dilating effect, thus dexmedetomidine was considered to be a viable sedative drug after cardiac surgery.