Zaarour Christian, Engelhardt Thomas, Strantzas Samuel, Pehora Carolyne, Lewis Stephen, Crawford Mark W
Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Spine (Phila Pa 1976). 2007 Oct 15;32(22):E627-30. doi: 10.1097/BRS.0b013e3181573eb4.
Randomized controlled trial. OBJECTIVE.: To determine the effect of low-dose ketamine on the voltage needed to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia in children undergoing scoliosis surgery.
Motor-evoked potentials (MEPs) are increasingly used to assess the integrity of motor pathways during surgery. Whereas most general anesthetics depress MEP amplitude, the effect of ketamine has been variable, ranging from little or no reduction to an increase in amplitude, suggesting that ketamine may be useful as an agent to facilitate MEP monitoring. We tested the hypothesis that low-dose ketamine would reduce the voltage required to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia.
Thirty-four patients 12 to 16 years of age undergoing posterior instrumentation for correction of idiopathic scoliosis were randomly assigned to receive low-dose ketamine (0.5 mg/kg bolus, followed by 4 microg/kg/min infusion) or an equal volume of saline. Anesthesia was maintained using a mixture of 30% oxygen in air, continuous infusion of propofol at a rate of 100 to 150 microg/kg per min, and continuous infusion of remifentanil. Myogenic motor-evoked responses to transcranial electrical stimulation of the motor cortex were recorded. The minimum voltage required to elicit maximal amplitude of the MEP response was determined. Voltage requirements were compared using the Mann-Whitney U rank sum test. P < 0.05 was considered statistically significant.
No significant difference was found in the minimal voltage needed to elicit maximum amplitude of the MEP response. Median (range) voltage requirements in the ketamine and control groups were 227 V (range, 160-350 V) and 215 V (range, 150-300 V), respectively.
Addition of low-dose ketamine to propofol/remifentanil anesthesia does not significantly reduce the voltage needed to elicit maximum amplitude of the motor-evoked response to transcranial electrical stimulation.
随机对照试验。目的：确定在接受脊柱侧弯手术的儿童丙泊酚/瑞芬太尼麻醉期间，小剂量氯胺酮对经颅电刺激诱发运动诱发电位最大振幅所需电压的影响。
运动诱发电位（MEP）越来越多地用于评估手术期间运动通路的完整性。虽然大多数全身麻醉药会降低MEP振幅，但氯胺酮的作用却不尽相同，从几乎没有降低到振幅增加，这表明氯胺酮可能是有助于MEP监测的药物。我们检验了这样一个假设，即在丙泊酚/瑞芬太尼麻醉期间，小剂量氯胺酮会降低经颅电刺激诱发运动诱发电位最大振幅所需的电压。
34例12至16岁接受后路器械矫正特发性脊柱侧弯的患者被随机分配接受小剂量氯胺酮（0.5mg/kg静脉推注，随后以4μg/kg/min输注）或等体积生理盐水。使用30%氧气与空气的混合气体、以100至150μg/kg每分钟的速率持续输注丙泊酚以及持续输注瑞芬太尼维持麻醉。记录对运动皮层经颅电刺激的肌源性运动诱发电位。确定诱发MEP反应最大振幅所需的最小电压。使用曼-惠特尼U秩和检验比较电压需求。P<0.05被认为具有统计学意义。
诱发MEP反应最大振幅所需的最小电压未发现显著差异。氯胺酮组和对照组的中位（范围）电压需求分别为227V（范围，160 - 350V）和215V（范围，150 - 300V）。
在丙泊酚/瑞芬太尼麻醉中添加小剂量氯胺酮并不能显著降低经颅电刺激诱发运动诱发电位最大振幅所需的电压。
