Cardioprotective effect of dexmedetomidine on patients underwent coronary artery bypass graft-ing

Objective To observe the cardioprotective effect of dexmedetomidine on patients underwent coronary artery bypass grafting. Methods There were fifty patients who were scheduled for coronary artery bypass grafting. These patients were 53 -71 years old,with a body mass index of 17 -25 kg/m^2 . They were randomly divided into two groups：saline group（ group C,25 cases）and dexmedetomidine group（ group D,25 cases）. The patients in the group D received an intravenous infusion of 1 μg/kg for 10 minutes. Then the infusion speed was adjusted to 0. 5 μg/（kg·h）until the end of surgery. An equivalent volume of normal saline was administered via the intravenous infusion in the group C. BP and HR were recorded at 10 min before operation（T1）,skin incision（T2）,chest opening（T3）, 10 min after aortic unclamping（ T4 ）and the end of operation（ T5 ）. Blood samples were taken from the radial artery for determination of plasma cardiac troponin T（cTnT）concentrations at T1,30 min after aortic clamping（ T6 ）,1 h after aortic unclamping（ T7 ）,6 h after aortic unclamping（ T8 ）and 24 h after aortic unclamping（ T9 ）. Results Compared with the baseline value at T1 ,there was no significant change in HR and BP at different time points in group D. HR and BP levels significantly increased at T2-T5 in group C（ P﹤0 . 05 ）. The plasma cTnI levels were significantly increased at T8 and T9 in the two groups （ P﹤0 . 05 ）. The plasma cTnI levels at T8 and T9 were significantly lower in group D than those in group C（ P﹤0. 05 ）. Conclusions Dexmedetomidine infusion is beneficial for keeping the hemodynamics stable and can protect myocardium in patients underwent coronary artery bypass grafting. Key words: Dexmedetomidine; Coronary artery bypass grafting; Hemodynamics; Cardioprotective effect