右美托咪定对颅内肿瘤手术患者脑脊液中氨基酸的影响

The effect of dexmedetomidine on amino acid in cerebro-spinal fluid of patients undergoing intracranial tumor surgery

目的：探讨右美托咪定对颅内肿瘤手术患者脑脊液中兴奋性和抑制性氨基酸的影响和右美托咪定在神经外科手术中的脑保护机制。方法选择择期脑肿瘤手术患者60例,年龄18-64岁,ASA Ⅰ或Ⅱ级,性别不限,体重50-90 kg。随机均分为两组：右美托咪定组（D 组）和对照组（C 组）。麻醉诱导前 D 组静脉输注右美托咪定1μg/kg,10 min 注完,C 组静脉注射咪达唑仑0.03-0.05 mg/kg。D 组持续静脉泵注右美托咪定0.2-0.7μg·kg-1·h-1,C 组间断给予咪达唑仑0.03-0.05 mg/kg。维持 BIS 值在40-50。记录麻醉诱导前（T0）、切开硬脑膜（T1）、切除肿瘤时（T2）、手术结束时（T3）的 MAP、HR。并于 T0、T3、术后6 h（T4）、12 h （T5）、24 h（T6）收集脑脊液,用高效液相色谱法检测脑脊液中兴奋性氨基酸谷氨酸（Glu）、天门冬氨酸（Asp）和抑制性氨基酸γ-氨基丁酸（GABA）的浓度。结果 T1-T3时 D 组 MAP 明显低于,HR 明显慢于 T0时和 C 组（P 〈0.05）。T3-T6时脑脊液中 C 组 Glu、Asp 浓度明显高于 T0时和 D 组（P 〈0.05）,GABA 浓度明显低于 D 组（P 〈0.05）。与 T0时比较,T3-T5时 D 组 Glu、Asp 浓度有升高、GABA 浓度有降低趋势,但差异无统计学意义,T6时恢复到 T0时水平。结论右美托咪定用于颅内肿瘤手术中可维持血流动力学稳定性,降低脑脊液中兴奋性氨基酸 Glu 和 Asp 浓度,有一定的脑保护作用。

Objective To investigate the effect of dexmedetomidine on excitatory aminoacid （EAA）and inhibition of amino acid（IAA）in cerebro-spinal fluid（CSF）of patients undergoing in-tracranial tumor surgery,and to explore the cerebral protective mechanism of dexmedetomidine in neurosurgery.Methods Sixty patients aged 18-64 years old,ASA Ⅰ or Ⅱ,weighing 50-90 kg un-dergoing elective intracranial tumor surgery were randomly divided into dexmedetomidine group （group D）and control group（group C）.Dexmedetomidine 1 μg/kg was infused before anesthesia in-duction for more than 10 minutes and pumped continously with 0.2-0.7 μg·kg-1·h-1 in group D, while in group C midazolam 0.03-0.05 mg/kg was injected followed by intermittent administration of 0.03-0.05 mg/kg.BIS value was maintained between 40-50.MAP and HR was recorded at the time points before induction（T0 ）,dura mater incision（T1 ）,tumor resection（T2 ）,at the end of the surgery （T3 ）.And we collected CSF at T0 ,T3 ,6 hours after the surgery（T4 ）,12 hours after the surgery （T5 ）,24 hours after the surgery（T6 ）,then the concentrations of EAA and IAA were determined with high-performance liquid chromatography （HPLC）at T0 ,T3 ,T4 ,T5 and T6 .Results The MAP and HR in group D at T1-T3 were much lower than that in T0 and in group C（P 〈0.05）.Compared with T0 ,the Glu and Asp in CSF significantly increased in group C at T3-T6 and were much higher than those in group D （P 〈 0.05 ）,GABA was significantly decreased and much lower than group D（P 〈0.05）.Compared with T0 ,the Glu and Asp in group D at T3-T5 were increased and GABA was decreased, but without statistic significance. At T6 , the values recovered to the level at T0 . Conclusion Dexmedetomidine can be used to maintain hemodynamic stability in intracranial tumor surgery,and may play a role in cerebral protection through inhibiting expression of Glu and Asp （EAA）.