Stühmeier K D, Grabitz K, Mainzer B, Sandmann W, Tarnow J
Institut für Klinische Anaesthesiologie, Heinrich-Heine-Universität, Düsseldorf, Germany.
Anesthesiology. 1993 Dec;79(6):1170-6; discussion 27A-28A.
To reduce the incidence of misleading assessments, and to derive criteria for critical spinal cord ischemia during thoracic or thoracoabdominal aortic aneurysm repair, the authors epidurally stimulated and recorded somatosensory evoked potentials (ESEP) below and above, respectively, the spinal segment at risk (electrospinogram).
Epidural somatosensory evoked potentials were analyzed in 100 consecutive patients undergoing resection of aortic aneurysms using two bipolar catheters (stimulation at the L2 level and recording at the T3 level) for the following criteria: 1) the time until ESEP disappeared completely after cross clamping, 2) the duration of complete ESEP loss during and after cross clamping, and 3) the time until ESEP recovered after declamping. Postoperatively, neurologic deficits were evaluated by a neurologist who was unaware of the ESEP recordings.
Three types of patients could be identified. First, thirty-one patients neither showed ESEP loss nor neurologic deficits. Second, ESEP loss occurring later than 15 min after cross clamping was associated with a neurologic deficit in 2 of 29 patients (6.9%). And, third, 12 of 40 patients (30%) presented a neurologic deficit when ESEP loss occurred within 15 min after cross clamping. Further indicators of an impending risk were a total ESEP loss greater than 40 min (sensitivity 100%, specificity 68%, positive predictive value [PPV] 35%, and negative predictive value [NPV] 100%), and a recovery of ESEP later than 20 min after declamping (sensitivity 93%, specificity 86%, PPV 52%, and NPV 99%).
Epidural somatosensory evoked potentials appeared to be a reasonable intraoperative predictor of postoperative neurologic outcome, and informs surgeons and anesthesiologists about the impending danger at an early state of the operation.
为降低误导性评估的发生率，并得出胸段或胸腹段主动脉瘤修复术中关键脊髓缺血的标准，作者分别在有风险的脊髓节段下方和上方进行硬膜外刺激并记录体感诱发电位（ESEP，即电脊髓图）。
对连续100例接受主动脉瘤切除术的患者进行硬膜外体感诱发电位分析，使用两根双极导管（在L2水平刺激，在T3水平记录），依据以下标准：1）阻断后ESEP完全消失的时间；2）阻断期间及阻断后ESEP完全消失的持续时间；3）松开阻断后ESEP恢复的时间。术后，由一名不了解ESEP记录情况的神经科医生评估神经功能缺损情况。
可识别出三种类型的患者。第一，31例患者既未出现ESEP消失，也未出现神经功能缺损。第二，阻断后15分钟后出现ESEP消失的29例患者中有2例（6.9%）出现神经功能缺损。第三，40例患者中有12例（30%）在阻断后15分钟内出现ESEP消失时出现神经功能缺损。即将发生风险的进一步指标包括ESEP完全消失超过40分钟（敏感性100%，特异性68%，阳性预测值[PPV]35%，阴性预测值[NPV]100%），以及松开阻断后20分钟后ESEP恢复（敏感性93%，特异性86%，PPV52%，NPV99%）。
硬膜外体感诱发电位似乎是术后神经功能结果合理的术中预测指标，能在手术早期告知外科医生和麻醉医生即将出现的危险。
