Effect of hypothermia on motor evoked potentials - interaction with anesthetics

我们研究了麻醉药和低温对兔模型肌源性MEPs的影响。l)氧化亚氮和异丙酚对氯胺酮和芬太尼麻醉家兔MEPs的影响。结果表明，氧化亚氮和异丙酚抑制单脉冲刺激引起的mep呈剂量依赖性。然而，氧化亚氮对MEPs的抑制作用可以通过列车脉冲刺激来逆转。2)低温对单次或列次脉冲刺激兔肌源性mep的影响。将食管温度依次控制在35、32、30、28℃，记录各温度下的mep值。结果表明，只要使用一系列脉冲进行刺激，将核心温度降低到28℃不会影响MEP振幅。3)亚低温对列车脉冲刺激致肌源性MEPs抑制的影响。将家兔随机分为3个温度组（40、35和30℃），分别给予30%、50%和70%的氧化亚氮。结果表明，在低温期间，氧化亚氮诱导的MEPs抑制可能会增强。这些数据表明，术中监测mep在28℃以上是可行的，但在低温时应仔细解释麻醉剂的影响。

We investigated the effects of anesthetics and hypothermia on myogenic MEPs in a rabbit model.l) The effects of nitrous oxide and propofol on MEPs in rabbits under ketamine and fentanyl anesthesia. The results indicated that nitrous oxide and propofol suppressed MEPs induced by single pulse stimulation in a dose-dependent manner. However, suppressive effect of nitrous oxide on MEPs could be reversed by application of train pulse stimulation.2) The effects of hypothermia on myogenic MEPs induced by single or train pulse stimulation in rabbits. Esophageal temperature was controlled at 35, 32, 30 and 28 degrees C in turn and MEPs were recorded at each temperature. The results indicate that a reduction of core temperature to 28 degrees C did not influence MEP amplitudes as long as a train of pulses were used for stimulation.3) The effects of hypothermia on nitrous oxide-induced suppression on myogenic MEPs induced by train pulse stimulation. The rabbits were randomly allocated to one of three temperature groups (40, 35, and 30 degrees C) and 30%, 50% and 70% of nitrous oxide was administered. The results suggested that nitrous oxide-induced suppression of MEPs may be augmented during hypothermia. These data suggested that intraoperative monitoring of MEPs are feasible above 28 degrees C, but the influence of anesthetics should be carefully interpreted during hypothermia.