小剂量氯胺酮对心内直视手术患者心肺转流后脑损伤的影响

Effect of low-dose ketamine on brain injury in patients undergoing open-heart surgery with cardiopulmonary bypass

目的观察小剂量氯胺酮对心内直视手术患者心肺转流(CPB)后脑损伤是否具有减轻作用并探讨其机制。方法40例择期心内直视手术患者,随机分为氯胺酮组(n=20)和对照组(n=20)。氯胺酮组于麻醉诱导后静脉注射氯胺酮0.5mg/kg,对照组给予等体积的生理盐水。分别于麻醉诱导前(T1),CPB前(T2),CPB后30min(T3),CPB结束时(T4),CPB结束后4h(T5),CPB结束后24h(T6),采取颈内静脉血,用酶联免疫法(ELLSA)检测血浆S100β蛋白的含量,放射免疫法测定肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)的浓度。记录术前1d和术后3d简易智能量表(MMSE)评分并进行脑功能临床评估。结果两组患者T3,T4,T5S100β蛋白水平均高于T1,与对照组相比,氯胺酮组在T3,T4,T5血浆S100β蛋白含量显著降低(P<0.05)。两组患者T3,T4,T5,T6TNF-α、IL-6水平明显高于T1,与对照组相比,氯胺酮组在T3,T4,T5血浆TNF-α、IL-6含量显著降低(P<0.05)。氯胺酮组术后3dMMSE评分高于对照组,认知功能下降的发生率低于对照组(P<0.05)。结论小剂量氯胺酮能减轻心内直视手术患者心肺转流后的脑损伤,抑制心肺转流诱导的过度炎症反应可能是其部分机制。

Objective To investigate if low-dose ketamine can alleviate brain injury in patients undergoing open-heart surgery with cardiopulmonary bypass（CPB） and explore its possible mechanisms.Methods Forty patients undergoing selective open-heart surgery with cardiopulmonary bypass were randomly divided into two groups：the ketamine group（n=20） and the control group（n=20）.In the ketamine group patients received ketamine（0.5 mg/kg） intravenous injection after induction of anesthesia;In the control group patients received an equal volume of normal saline instead of ketamine.Blood samples were taken from the internal jugular vein before anesthesia（T1）,before CPB（T2）,30 minutes after CPB（T3）,at the end of CPB（T4）,4 hours（T5） and 24 hours（T6） after the end of CPB.Serum S100β protein was determined by the ELLSA method,and TNF-α and IL-6 were assayed by radioimmunoassay.The mini-mental state examination（MMSE） scores on the day before surgery and 3 days after surgery were recorded to evaluate brain function.Results The plasma level of S100β significantly increased from T3 to T5,as compared with the baseline value at T1 in both groups;S100β protein levels in the ketamine group were significantly lower than those in the control group from T3 to T5（P〈0.05）.The plasma levels of TNF-α and IL-6 significantly increased from T3 to T6,as compared with the baseline value at T1 in both groups,and TNF-α and IL-6 in the ketamine group were significantlylower than those in the control group from T3 to T5（P〈0.05）.MMSE scores in the ketamine group were higher than those in the control group,and the incidence of cognitive decline was lower than that in the control group.Conclusion Low-dose ketamine can alleviate brain injury in patients undergoing open-heart surgery with CPB,and its suppression of inflammatory reaction after CPB may be its partial mechanism.