小剂量氯胺酮对颅脑手术患者的脑保护作用

Cerebral protective effect of low-dose ketamine during brain surgery

目的观察小剂量氯胺酮对颅脑手术患者的脑保护作用。方法拟行开颅手术的颅内肿瘤患者20例,随机分为2组(n=10),对照组(C组)和氯胺酮组(K组)。开放静脉通道后均在左侧卧位下行L_(3,4)间隙蛛网膜下腔穿刺置管,以监测颅内压和抽取脑脊液用,足背动脉穿刺置管监测动脉压。K组麻醉诱导后静脉注射氯胺酮0．2mg／kg,然后以6μg．kg^(-1)·min^(-1)持续静脉输注至缝皮；C组给予等量生理盐水。分别于麻醉诱导前即刻(T_0)、手术开始后2 h(T_1)、术毕(T_2)以及术后1 d(T_3)抽取足背动脉血,测定血浆白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)浓度；同时抽取脑脊液,测定星状细胞胶质蛋白(S-100)浓度。结果与T_0时比较,K组T_(2,3)时IL-6、TNF-α、S-100浓度升高(P＜0．05),C组T_(2,3)时IL-6浓度升高、T_(1～3)时TNF-α、S-100浓度升高(P＜0．05)；与C组比较,T_3时IL-6、T_(1～3)时TNF-α浓度及T_(1,2)时S-100浓度降低(P＜0．01)；两组去颅骨及术毕时ICP均低于基础值,两组间差异无统计学意义(P＞0．05)。结论小剂量氯胺酮对颅脑手术患者脑具有一定的保护作用。

Objective To investigate the cerebral protective effect of low-dose ketamine in patients undergoing brain surgery for intracranial tumor. Methods Twenty ASA Ⅱ patients aged 18-62 yrs weighing 49-78 kg were randomly divided into 2 groups （n = 10 each）： group Ⅰ ketamine （K） and group Ⅱ control （C）. The patients were premedicated with intramuscular luminal 0.1 g and atropine 0.5 mg. Anesthesia was induced with midazolam 0.15 mg· kg^-1 , fentanyl 5 μg · kg^-1 and vecuronium 0.12 mg· kg^-1 and maintained with 1.5% isoflurane and continuous infusion of fentanyl 2 μg· kg^- 1· min^ -1 and intermittent i.v. boluses of vecurenium. The patients were intubated and mechanically ventilated. PET CO2 was maintained at 30 mm Hg. In group K ketamine 0.2 mg · kg^-1 was given after induction of anesthesia followed by infusion at 6 μg · kg^-1 · min^-1 which was maintained until skin closure. In group C equal volume of normal saline was given instead of ketamine. A catheter was placed in the subarachnoid space at L3-4 for collection of CSF and monitoring of intracranial pressure （ICP）. A dorsalis pedis was cannulated for continuous direct BP monitoring and blood sampling. ECG, BP, HR, SpO2, PErCO2 and ICP were monitored during operation. Arterial blood samples were taken immediately before induction （T0）, 2h after skin incision （T1）, at the end of operation （T2） and on the morning of the 1st postoperative day （T3 ） for determination of plasma TNF-α and IL-6 concentrations. CSF was collected at the same time points for determination of S-100 concentration. Results The two groups were comparable with respect to age, M/F sex ratio, body weight, duration of operation and intraoperative blood loss. The plasma IL-6 and TNF-α concentrations were significantly increased during and after operation as compared to the baseline values at To in both groups and were significantly higher in group C than in group K. No S-100 was detected in CSF at TO but CSF S-100 concentration was significantly increased during and after operation in both groups and was significantly higher in group C than in group K. Conclusion Low-dose ketamine has cerebral protective effect during brain surgery.