Giannoni M F, Sbarigia E, Panico M A, Speziale F, Antonini M, Maraglino C, Fiorani P
I Cattedra di Chirurgia Vascolare, Università di Roma, La Sapienza, Italy.
Eur J Vasc Endovasc Surg. 1996 Nov;12(4):407-11. doi: 10.1016/s1078-5884(96)80004-9.
Studies comparing transcranial Doppler ultrasonography (TCD) with other intraoperative monitoring techniques for detecting clamping ischaemia during carotid endarterectomy under general anaesthesia suggest that a reduction of > two-thirds in the mean middle cerebral artery velocity (mMCAv) or a reduction of > 0.4 in the preclamping mMCAv: clamping mMCAv ratio warrants cerebral protection. Our aim was to study the relationship between mMCAvs and clamping ischaemia during carotid endarterectomy in awake patients.
In a consecutive series of 57 patients undergoing carotid endarterectomy under locoregional anaesthesia 51 were monitored by intraoperative TCD, continuous EEG, and neurologic awake testing.
Five of the 51 (9.8%) patients had transient clamping ischaemia, which carotid shunting reversed. TCD showed that these five patients had significant lower mean mMCAvs than the other 46 patients, who had no deficits (1.8 +/- 1.1 cm/s vs. 26.2 +/- 8.5, p = 0.0003). Current TCD criteria indicated that four other patients (7.8%) should have been shunted. All four had significantly higher clamping mMCAvs than the five shunted patients (11.5 +/- 1.9 vs. 1.8 +/- 1.1, p = 0.0012).
Intraoperative TCD detected cerebral ischaemia and yielded no false-negative. An mMCAv of 10 cm/s or less may indicate the risk of clamping ischaemia better than the higher threshold currently proposed. This would avoid unnecessary shunting due to false-positives.
多项研究比较了经颅多普勒超声（TCD）与其他术中监测技术在全身麻醉下颈动脉内膜切除术期间检测夹闭缺血情况，结果表明大脑中动脉平均血流速度（mMCAv）降低超过三分之二，或夹闭前mMCAv与夹闭时mMCAv的比值降低超过0.4时，需要进行脑保护。我们的目的是研究清醒患者颈动脉内膜切除术期间mMCAv与夹闭缺血之间的关系。
在连续57例行局部麻醉下颈动脉内膜切除术的患者中，51例接受了术中TCD、连续脑电图监测和神经功能清醒测试。
51例患者中有5例（9.8%）出现短暂夹闭缺血，颈动脉分流可逆转缺血。TCD显示，这5例患者的平均mMCAv显著低于其他46例无神经功能缺损的患者（1.8±1.1 cm/s对26.2±8.5，p = 0.0003）。目前的TCD标准表明，另有4例患者（7.8%）应进行分流。这4例患者夹闭时的mMCAv均显著高于5例接受分流的患者（11.5±1.9对1.8±1.1，p = 0.0012）。
术中TCD可检测到脑缺血且无假阴性结果。与目前提出的较高阈值相比，mMCAv为10 cm/s或更低可能更能提示夹闭缺血风险。这将避免因假阳性结果导致的不必要分流。
