氯胺酮对体外循环心脏手术患者的脑保护作用

Cerebral protective effect of ketamine in patients undergoing cardiac surgery under cardiopulmonary bypass

目的观察氯胺酮对体外循环(CPB)下心脏手术患者的脑保护作用。方法择期行二尖瓣置换术患者40例,ASAⅡ～Ⅲ级,随机分为氯胺酮组(K组)和对照组(C组),每组20例。两组均以咪唑安定、舒芬太尼、哌库溴铵进行麻醉诱导及维持。K组诱导后静脉注射氯胺酮2mg/kg,继以50μg/(kg.min)持续输注至手术结束,C组给予等量生理盐水。桡动脉和右颈内静脉置管监测动脉压和中心静脉压,并经右颈内静脉逆行置管至颈静脉球部以采集血液标本。分别于麻醉诱导后(T1)、CPB后20min(T2)、CPB结束(T3)、术毕(T4)、术后24h(T5)抽取动脉血及颈静脉球部血行血气分析,计算脑氧摄取率(ERO2),并测定颈静脉球血S100β蛋白浓度。结果与C组比较,K组脑ERO2在T2～4时间点明显降低(P<0.05)。与T1比较,两组S100β蛋白浓度在T2～5时间点明显升高(P<0.05);与C组相比,K组S100β蛋白在T2～5各时间点均显著降低(P<0.05)。结论氯胺酮对体外循环下心脏手术患者具有一定脑保护作用。

Objective To investigate the cerebral protective effect of ketamine during cardiac surgery performed under CPB.Methods Forty ASA Ⅱ～Ⅲ patients undergoing elective mitral valve replacement under CPB were randomly divided into 2 groups with 20 cases each: ketamine group(K) and control group(C). Anesthesia was induced and maintained with midazolam, sufentanyl and pipecuronium. After induction, bolus of 2 mg/kg of ketamine was given intravenously followed by a continuous infusion of 50 μg/(kg·min) in group K until the end of operation. In group C equal volume of normal saline was given instead of ketamine. Radial artery was cannulated for continuous MAP mornitoring. Right internal jugular vein was cannulated and the catheter was advanced in a cephalad direction into the jugular bulb. Blood samples were taken from radial artery and jugular vein bulb after induction of anesthesia (before ketamine injection)(T1), 20 min after CPB(T2), at the end of CPB(T3), at the end of operation (T4) and 24 h after operation (T5). At each time point, the changes of arterial and jugular venous hemoblobin saturation (SaO2 and SjvO2) were observed, and cerebral oxygen extraction rate(ERO2)was calculated. Plasma S100β protein concentration in jugular vein bulb was determined by ELISA. Results Cerebral oxygen extraction rate in group K was significantly lower than that in group C at T2~4(P<0.05). Plasma S100β protein concentrations were significantly higher at T2~5 than those at T1 in both groups(P<0.05); It was significantly lower in group K than that in group C at T2~5(P<0.05).Conclusion Ketamine has cerebral protective effect to some extent during cardiac surgery performed under CPB.