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）对主动脉阻断时脊髓缺血的诊断价值。采用大鼠脊髓缺血模型，经颅运动诱发电位监测可在主动脉阻断后2 min内检测到脊髓缺血，比体感诱发电位检测脊髓缺血快得多。从SEP高频分析来看，SEP高频分析不能反映脊髓功能，而只能反映脊髓上的功能。因此，我们的结论是，SEP的高频分析不能作为新的脊髓功能监测主动脉手术。然而，在本项目中，我们发现经颅运动诱发电位监测可以提供对主动脉阻断后脊髓缺血的快速检测，并且代表与MEP和SCEP评估缺血性脊髓功能障碍的50%概率相关的主动脉阻断间期的P50_<MEP>和P50_分别为0.3+/- 0.1 min和6.2+/- 0.5 min<SCEP>，我们的数据表明，与节段性SCEP监测相比，tc-MEP监测可以如此快速地检测脊髓缺血的发作，节段性SCEP监测可以在包括脊髓保护的手术方法中提供治疗窗口。

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.