Hemodynamics in coronary artery bypass surgery: effects of intraoperative dexmedetomidine administration

Dexmedetomidine is an α2-receptor agonist which is increasingly being used in coronary artery bypass grafting (CABG) surgery due to its suppressive effect on the stress responses against intubation and surgery. In this study effects of dexmedetomidine administration as an adjuvant agent during induction and maintenance of anesthesia on intraoperative hemodynamic changes were studied in patients undergoing CABG.

A total of 20 patients undergoing CABG were included in the study. At the beginning dexmedetomidine infusion of 1 µg/kg body weight (BW)/h was performed for 10 min. After this the infusion dosage of dexmedetomidine was decreased to 0.2-0.4 µg/kgBW/h, 0.15 mg/kgBW of cisatracurium was administered for intubation and 0.5 MAC (minimum alveolar concentration) sevoflurane was administered as a volatile anesthetic. Heart rate (HR), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), cardiac output (CO), systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were recorded 10 min after dexmedetomidine infusion, following intubation, during skin incision and sternotomy, before and after the bypass and in the postoperative period.

With dexmedetomidine infusion HR and MAP were found to be moderately decreased in comparison to baseline values and no severe bradycardia or hypotension requiring intervention occurred. No increase in HR and MAP values were recorded during sternotomy and bypass. The MPAP evaluation showed no difference between the preoperative and intraoperative values (p>0.05). The cardiac output (CO) was found to be low starting from the time of skin incision to just before the bypass, compared to preoperative values (p<0.05) and SVR was moderately decreased with initial high dose infusion and after that increased to baseline values (p<0.05).

Dexmedetomidine can be safely used in CABG operations delivering a stable hemodynamic status throughout the operative period.