Effects of dexmedetomidine on inflammatory responses in patients undergoing cardiac valve replacement with cardiopulmonary bypass

Objective To evaluate the effects of dexmedetomidine on inflammatory responses in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Thirty ASA physical status Ⅱ or Ⅲ patients of both sexes,aged 45-64 yr,weighing 50-80 kg,scheduled for elective cardiac valve replacement with CPB,were equally and randomly divided into 2 groups using a random number table:control group (group C) and dexmedetomidine group (group D).Anesthesia was induced with iv injection of midazolam,sufentanil,etomidate and rocuronium.The patients were endotracheally intubated and mechanically ventilated.A loading dose of dexmedetomidine 1 μg/kg was injected intravenously over 10 min after induction,followed by continuous infusion at 0.05 μg· kg-1 · h-1 until the end of operation in group D.While the equal volume of normal saline was given in group C.Anesthesia was maintained with inhalation of sevoflurane,iv infusion of sufentanil and intermittent iv boluses of rocuronium.Before induction (T0),at 10 min after termination of CPB (T1),at the end of operation (T2),and at 6 and 24 h after operation (T3,4),the jugular bulb venous blood samples were taken for determination of serum concentrations of tumor necrosis factor-apha (TNF-α),interleukin-6 (IL-6),S100β protein and neuron-specific enolase (NSE).Results Compared with group C,the serum TNF-α concentrations at T1 4,IL-6 concentrations at T24,S100β protein concentration at T3,4 and NSE concentration at T1,2 were significantly decreased in group D (P ＜ 0.05).Conclusion Dexmedetomidine infused at 0.05 μg· kg-1 · h-1 after a loading dose of 1 tg/kg can reduce inflammatory responses,thus reducing cerebral injury in patients undcrgoing cardiac valve replacement with CPB. Key words: Dexmedetomidine;  Cardiopulmonary bypass;  Inflammation