Protective effect of dexmedetomidine in coronary artery bypass grafting surgery

The aim of this study was to observe the impact of dexmedetomidine on postoperative myocardial injury in patients undergoing off‑pump coronary artery bypass (OPCAB) grafting. One hundred and sixty‑two patients who were undergoing OPCAB surgery were randomly divided into control and dexmedetomidine groups (groups C and Dex, respectively). Following the first vascular anastomosis grafting, the patients in group Dex received a continuous intravenous infusion of 0.2‑0.5 µg/kg/h dexmedetomidine, until they were transferred to the Cardiac Surgery intensive care unit (ICU) for 12 h. Patients in group C received physiological saline intraoperatively and an intravenous infusion of 2‑4 mg/kg/h isopropylphenol for postoperative sedation. Invasive arterial pressure and heart rate were continuously monitored for 5 min subsequent to entry into the operating theatre (T0), immediately following surgery (T1), 12 h post‑surgery (T2), 24 h post‑surgery(T3), 48 h post‑surgery(T4) and 72 h post‑surgery (T5). Blood samples were taken to determine the plasma levels of cardiac troponin I (cTnI) and creatine kinase‑MB (CK‑MB) at each time point. At 72 h post‑surgery, a dynamic electrocardiogram was monitored. The blood pressure, heart rate, levels of cTnI, CK‑MB, norepinephrine and cortisol, and postoperative arrhythmic events in the patients in group Dex all decreased compared with those in group C. The duration of mechanical ventilation and ICU residence time were also shorter than those in the control group (P<0.05). Dexmedetomidine reduced post‑surgical myocardial injury in patients who had undergone OPCAB surgery.