右美托咪定对单肺通气患者开胸术后认知功能障碍的影响

Effect of dexmedetomidine on cognitive dysfunction after thoracic surgery in patients undergoing one-lung ventilation

目的评价右美托咪定对单肺通气患者开胸术后认知功能障碍（POCD）的影响。方法择期开胸术患者62例，年龄45～64岁，体重指数17．5～25．5kg／m^2。采用随机数字表法，将患者分为右美托咪定组（Dex组）和对照组（C组），每组31例。Dex组于麻醉诱导前静脉泵注右美托咪定0．5μg／kg，泵注10min，随后静脉泵注0．5μg·kg^-1·h^-1至手术结束前30min；C组给予等量生理盐水。于麻醉诱导前、术后24、48和72h时采集静脉血标本，采用ELISA法检测血清S-100β蛋白和神经元特异性烯醇化酶（NSE）水平。术后72h时采用简明心智评分测验量表评定POCD的发生情况。结果与麻醉诱导前比较，2组术后各时点血清S-100β蛋白和NSE水平升高（P〈0．01）；与C组比较，Dex组术后各时点血清S-100β蛋白及NSE水平降低（P〈0．01），术后72h时POCD发生率明显降低（26％vs6％，P〈0．05）。结论右美托咪定可有效减轻单肺通气开胸术患者的神经损伤，明显抑制POCD发生，提示其适宜作为开胸术麻醉用药。

Objective To evaluate the effect of dexmedetomidine on cognitive dysfunction after thoracic surgery in patients undergoing one-lung ventilation. Methods Sixty-two patients, aged 45-64 yr, of ASA physical status Ⅰ or Ⅱ, with body mass index ranged from 17.5 to 25.5 kg/m^2, scheduled for elective thoracic surgery, were randomly allocated into 2 groups （n = 31 each） using a random number table： dexmedetomidine group （Dex group） and control group （C group）. Dexmedetomidine 0.5 μg/kg was infused for 10 min starting from the time point before induction of anesthesia, followed by continuous infusion at a rate of 0.5 μg · kg^-1 · h^-1 until 30 min before the end of surgery in Dex group. The equal volume of normal saline was administered instead in group C. Before induction and at 24, 48 and 72 h after surgery, venous blood samples were collected for determination of levels of S-100 beta protein and neuronspecific enolase in serum by ELISA. Cognitive function was assessed by Mini-Mental State Examination at 72 h after surgery. Results The levels of S-100 beta protein and neuron-specific enolase in serum were significantly increased after surgery than before induction in the two groups. Compared to C group, the levels of S-100 beta protein and neuron-specific enolase in serum were significantly decreased after surgery, and the incidence of postoperative cognitive dysfunction was decreased in Dex group （26% vs 6%）. Conclusion Dexmedetomidine can effectively reduce the nerve damage during one-lung ventilation and significantly inhibit the development of postoperative cognitive dysfunction in patients undergoing thoracic surgery, indicating that dexmedetomidine is suitable for thoracic surgery.