Effect of dexmedetomidine on cerebral injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of dexmedetomidine on the cerebral injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB).Methods Forty ASA Ⅱ or Ⅲ patients of both sexes,aged 43-64 yr,scheduled for elective cardiac valve replacement,were randomly divided into 2 groups (n =20 each)control group (group C) and dexmedetomidine group (group D).Dexmedetomidine 0.6 μg/kg was injected intravenously over 15 min before induction of anesthesia,followed by infusion at 0.2μg· kg-1 · h-1 until the end of operation in group D.While the equal volume of normal saline was given in group C.Blood samples were obtained from the radial artery and jugular bulb for blood gas analysis before CPB,immediatelv after declamping of the ascending aorta,at the end of CPB and at 6 h after operation (T1-4).The arteriovenous blood O2 difference (Da-jvO2) and cerebral O2 extraction rate (CERO2) were calculated.The plasma concentrations of S-100β and neuron-specific enolase (NSE) in the blood samples obtained from the jugular bulb were measured at T1-4 and 24 h after operation.Results Compared with group C,the jugular venous oxygen saturation was significantly increased and Da-jvO2 and CERO were decreased at T2,3,and the plasma concentrations of S100β and NSE were decreased at T2-4 in group D (P ＜ 0.05).Conclusion Dexmedetomidine can decrease the cerebral O2 metabolic rate and reduce the cerebral injury in patients undergoing cardiac valve replacement under CPB.