New spinal cord functional monitoring for aortic surgery-HFO analysis

本研究旨在探讨高频体感诱发电位（SEP）在主动脉交叉夹持过程中检测脊髓缺血的有效性。采用大鼠脊髓缺血模型，经颅运动诱发电位监测可以在主动脉交叉夹闭后2min内检测到脊髓缺血，比体感诱发电位检测脊髓缺血要快得多。根据SEP的高频分析，SEP的高频分析不反映脊髓功能，而是反映棘上功能。因此，我们的结论是，高频SEP分析不能作为主动脉手术脊髓功能监测的新方法。然而，在本项目中，我们发现经颅运动诱发电位监测可以快速检测主动脉闭塞后脊髓缺血，P50_<MEP>和P50_<SCEP>分别代表主动脉闭塞间隔，MEP和SCEP评估缺血性脊髓功能障碍的50%概率分别为0.3+/- 0.1 min和6.2+/- 0.5 min。我们的数据表明，与节段性SCEP监测相比，tc-MEP监测可以如此迅速地检测脊髓缺血的发生，这可以为包括脊髓保护在内的手术入路提供治疗窗口。

The aim of this project was to investigate whether High frequency analysis of Somatosensory evoked potentials (SEP) can provide excellent efficacy for detecting the spinal cord ischemia during aortic cross clamping. Using the rat's spinal cord ischemic model, transcranial motor evoked potential monitoring can detect the spinal cord ischemia within 2min after aortic cross clamp, which was much faster to detect spinal cord ischemia than that by somatosensory evoked potentials. According to high frequency analysis of SEP, high frequency of analysis of SEP did not reflect spinal cord function, but supraspinal function. Therefore, our conclusion was that high frequency analysis of SEP could not be new spinal cord functional monitoring for aortic surgery. However, in this project, we found that transcranial motor evoked potentials monitoring can provide rapid detection for spinal cord ischemia after aortic occlusion, and the P50_<MEP> and P50_<SCEP> which represent the interval of aortic occlusion associated with 50 % probability of assessment of ischemic spinal cord dysfunction by MEP and SCEP were 0.3+/- 0.1 min and 6.2+/- 0.5 min, respectively.Our data indicated that tc-MEP monitoring could detect the onset of spinal cord ischemia so rapidly in comparison with segmental SCEP monitoring, which could provide therapeutic windows in a surgical approach that includes spinal cord protection.