摘要目的 比较七氟醚、异氟醚和地氟醚对神经外科手术患者经颅电刺激运动诱发电位(MEPs)的影响.方法 择期行神经外科手术患者60例,年龄18～64岁,ASA分级Ⅰ或Ⅱ级.随机分为3组(n=20):七氟醚组、异氟醚组和地氟醚组.监测BIS值和经颅电刺激MEPs.调节七氟醚、异氟醚和地氟醚吸入浓度,使其呼气末浓度分别达到0.50、0.75、1.00和1.30 MAC,每一浓度均维持15 min,视为稳态呼气末浓度.于给予吸入麻醉药前(基础状态)和达到各稳态呼气末浓度(T1-4)时,记录MEPs的波幅和潜伏期以及BIS值.记录MEPs波形记录失败情况.结果 与七氟醚组和异氟醚组比较,地氟醚组T1.2时波幅和BIS值降低,T1-4时潜伏期延长(P＜0.05);七氟醚组和异氟醚组各指标比较差异无统计学意义(P＞0.05).七氟醚组、异氟醚和地氟醚组基础状态、T1、T2时的记录失败率均为0;T3时记录失败率分别为0、5%和20%,三组比较差异无统计学意义(P＞0.05);T4时记录失败率分别为5%、20%和45%,与七氟醚组和异氟醚组比较,地氟醚组记录失败率升高(P＜0.05);七氟醚组和异氟醚组比较差异无统计学意义(P＞0.05).结论 地氟醚对神经外科手术患者经颅电刺激MEPs的抑制作用强于七氟醚和异氟醚.术中行MEPs监测时,七氟醚和异氟醚适宜的呼气末浓度为1.00 MAC,地氟醚为0.75～1.00 MAC.

abstractsObjective To compare the effects of sevoflurane,isoflurane and desflurane on transcranial electrical motor evoked potentials(MEPs)in patients undergoing neurosurgery.Methods Sixty ASA Ⅰ or Ⅱ patients aged 18-64 yr undergoing neurosurgery were randomly divided into 3 groups(n = 20 each): sevoflurane group,isoflurane group and desflurane group.BIS value and MEPs were monitored.The end-tidal concentrations of sevoflurane,isoflurane and desflurane were adjusted and maintained at 0.50,0.75,1.00 and 1.30 MAC respectively for at least 15 min during 6 stimuli delivered at 1000 Hz and 300 V lasting for 75 μs.The amplitudes and latency of MEPs and BIS value were recorded before administration(baseline)and the each stable state (T1-4).The failure rate of MEPs was also recorded.Results The amplitude of MEPs and BIS value were significantly decreased at T1.2 and the latency of MEPs was prolonged at T1-4 in desflurane group compared with sevoflurane and isoflurane groups(P＜0.05).There was no significant difference in the amplitudes and latency of MEPs and BIS value between group sevoflurane and isoflurane(P＞0.05).The failure rates of MEPs were 0 at baseline,T1 and T2,0,5% and 20% at T3 ,and 5%,20% and 45% at T4 in sevoflurane,isoflurane and desflurane groups respectively.The failure rate of MEPs was significantly higher in desflurane group than in sevoflurane and isoflurane groups(P＜0.05).Conclusion Desflurane has greater suppressive effect on MEPs than sevoflurane and isoflurane.1.00 MAC of sevoflurane and isoflurane,while 0.75-1.00 MAC of desflurane may be the suitable end-tidal concentration for MEP monitoring.