Dinkel M, Kamp H D, Schweiger H
Institut für Anaesthesiologie, Universität Erlangen-Nürnberg.
Anaesthesist. 1991 Feb;40(2):72-8.
During carotid surgery a monitoring device that will identify patients with inadequate cerebral perfusion and impending cerebral damage after carotid clamping is desirable. Such patients may benefit from cerebral protective measures, which should be applied selectively as their use can also lead to complications. METHODS. In order to evaluate the reliability of somatosensory evoked responses as a means of detecting patients with insufficient collateral perfusion after carotid cross clamping, a prospective study involving 482 operations for reconstruction of supraaortic vessels was performed. Somatosensory evoked potentials (SEPs) were recorded from a cervical (C2-Fz) and a parietal (C3'/C4'-Fz) electrode above the ipsilateral hemisphere following stimulation of the contralateral median nerve. RESULTS. In 22 procedures (4.6%) complete flattening of the cortical SEP occurred after carotid cross clamping. In 7 of 9 cases in which no indwelling shunt was used despite electrical silence neurological deficits were found postoperatively. The SEP amplitude was restored in 12 of the remaining 13 patients with complete loss of the SEP after shunt insertion. Only 3 of these patients demonstrated neurological impairment. During 460 operations evoked potentials were always present. Nevertheless, 5 neurological sequelae were noticed despite unchanged SEP after carotid artery clamping. All deficits, however, were caused by embolization and were unrelated to reduced blood flow after carotid cross clamping. CONCLUSIONS. Our results confirm the reliability of SEP monitoring for the detection of significant cerebral ischemia after carotid clamping. In absence of the cortical SEP immediate shunt placement is necessary to avoid neurological deficits. On the other hand, the risks attendant on indiscriminate cerebral support (embolism after shunt placement, cardiac ischemia due to induced hypertension) can be avoided in the presence of cortical potentials. This allows protection of the heart and the brain by anesthetic management and enables the surgeon to perform endarterectomy with no hurry, to avoid technical failure. SEP data may also be helpful in decision making on reoperation to look for sources of embolization. In conclusion, advanced monitoring by somatosensory evoked responses may help to improve the outcome of carotid surgery.
在颈动脉手术中，需要一种监测装置，能够识别出在颈动脉夹闭后脑灌注不足和即将发生脑损伤的患者。这类患者可能会从脑保护措施中获益，但这些措施也可能导致并发症，因此应选择性应用。方法：为了评估体感诱发电位作为检测颈动脉交叉夹闭后侧支灌注不足患者的手段的可靠性，我们进行了一项前瞻性研究，涉及482例主动脉弓上血管重建手术。在对侧正中神经受刺激后，从同侧半球上方的颈部（C2-Fz）和顶叶（C3'/C4'-Fz）电极记录体感诱发电位（SEP）。结果：在22例手术（4.6%）中，颈动脉交叉夹闭后皮质SEP完全消失。在9例尽管电信号消失但未使用留置分流管的病例中，有7例术后出现神经功能缺损。在其余13例SEP完全消失的患者中，有12例在插入分流管后SEP振幅恢复。这些患者中只有3例出现神经功能损害。在460例手术中，诱发电位始终存在。然而，尽管颈动脉夹闭后SEP未改变，仍发现5例神经后遗症。不过，所有缺损均由栓塞引起，与颈动脉交叉夹闭后血流减少无关。结论：我们的结果证实了SEP监测在检测颈动脉夹闭后严重脑缺血方面的可靠性。如果皮质SEP消失，应立即放置分流管以避免神经功能缺损。另一方面，在存在皮质电位的情况下，可以避免不加区别地进行脑支持所带来的风险（分流管放置后的栓塞、诱导性高血压引起的心脏缺血）。这使得通过麻醉管理保护心脏和大脑成为可能，并使外科医生能够从容地进行内膜切除术，避免技术失败。SEP数据也可能有助于在再次手术寻找栓塞源时做出决策。总之，体感诱发电位的高级监测可能有助于改善颈动脉手术的结果。
