无肌松药全凭静脉麻醉对脊柱侧凸手术患者运动诱发电位监测的影响

Effects of total intravenous anesthesia without muscle relaxants on motor evoked potential monitoring during scoliosis surgery

目的评价无肌松药全凭静脉麻醉对脊柱侧凸手术患者运动诱发电位（MEP）监测的影响。方法择期行脊柱侧凸后路融合术患者50例，性别不限，年龄18～25岁，ASA分级I或Ⅱ级，采用随机数字表法，将患者随机分为2组（n=25）：肌松药复合全凭静脉麻醉组（1组）和无肌松药全凭静脉麻醉组（Ⅱ组）。2组均经20min静脉输注右美托咪定负荷量1μg／kg，随后以0．2μg·kg-1·hp-1速率维持。给予右美托咪定负荷量后进行麻醉诱导，气管插管，机械通气。麻醉维持：静脉输注瑞芬太尼0．2μg·kg-1·min-1和丙泊酚80～120μg·kg-1·min-1维持脑电双频谱指数值40～60；静脉输注顺阿曲库铵0．5～1．5μg·kg-1·min-1，采用四个成串刺激监测肌松程度，维持L45％．55％，II组于椎旁肌肉分离完毕前30min停用顺阿曲库铵。记录停用肌松药期间MEP监测情况，并由外科医生评价肌松程度。记录成功唤醒情况。结果与I组比较，II组MEP监测成功率升高（P〈0．05），肌松程度差异无统计学意义（P〉0．05）。2组患者均成功唤醒。结论无肌松药全凭静脉麻醉用于脊柱侧凸手术患营可在满足手术所需肌松程度的同时，提高MEP临测的成功机率。

Objective To evaluate the effects of total intravenous anesthesia without muscle relaxants on motor evoked potential （MEP） monitoring during scoliosis surgery. Methods Fifty ASA I or II patients of both sexes, aged 18-25 yr, scheduled for posterior spinal fusion surgery, were randomly divided into 2 groups with 25 patients in each group： muscle relaxants combined with total intravenous anesthesia group （group I ） and total in- travenous anesthesia without muscle relaxant group （group II ） In both groups, a loading dose of dexmedetomidine 1 μg/kg was infused over 20 min, followed by infusion at 0.2 μg kg-1 h-1 . After the loading dose of dexmedeto- midine was given, anesthesia was induced, the patients were tracheal intubated and mechanieally ventilated. Anes- thesia was maintained with remifentanil 0.2 μg·kg-1·min-1 and propofol 80-120 μg·kg-1·min-1 . The bispectral index value was maintained at 40-60. Train of four stimulation of ulnar nerve was used to monitor the neuro-muscu- lar block. Cisatracurium was infused at 0.5-1.5 μg·kg-1·min-1 , T1 was maintained at 45%-55% , and the infu- sion was stopped 30 rain before the isolation of paraspinal muscles was completed in group II . MEP were monitored and recorded during the period when the administration of the muscle relaxation was stopped, and the degree of muscle relaxation was assessed by the surgeon. The successful wake-up test was recorded. Results The incidence of successful MEP monitoring was significantly higher in group II than in group l （ P 〈 0.05）. There was no sig- nificant difference in the degree of muscle relaxation between the two groups （ P 〉 0.05）. All the patients were successfully woken up. Conclusion Total intravenous anesthesia without muscle relaxants can provide satisfactory muscle relaxation for scoliosis surgery and increase the probability of successful MEP monitoring simuhaneously.