Lawrence P F, Alves J C, Jicha D, Bhirangi K, Dobrin P B
University of Utah School of Medicine, Department of Surgery, Salt Lake City 84132, USA.
J Vasc Surg. 1998 Feb;27(2):329-34; discussion 335-7. doi: 10.1016/s0741-5214(98)70363-5.
Controversy exists regarding the best technique to identify cerebral ischemia during carotid endarterectomy (CEA). Regional anesthesia allows continuous evaluation of neurologic function and therefore can help determine the incidence, timing, and causes of cerebral ischemia.
The timing and clinical manifestations of any neurologic event during CEA and as long as 30 days afterward was determined by review of operative reports, hospital charts, and outpatient records of consecutive patients who underwent CEA under regional anesthesia over a 68-month period.
Two hundred patients underwent CEA; indications were asymptomatic stenosis > 60% in 25%, transient ischemic attack with stenosis > 50% in 52%, and prior stroke with stenosis > 50% in 23%. Eight patients (4%) were converted to general anesthesia for non-ischemic reasons. Of the remaining 192 patients, 183 (95.5%) underwent the procedure with regional anesthesia and no shunt, 2% had cerebral ischemia and underwent shunt placement, and 2.5% had cerebral ischemia, were converted to general anesthesia, and underwent shunt placement. Cerebral ischemia developed in nine patients after carotid cross-clamping, manifested by loss of consciousness in four, confusion in two, dysarthria and confusion in one, and decreased contralateral motor strength in two. Immediate cerebral ischemia developed in four of the nine patients within 1 minute of cross-damping; all four underwent shunt placement. In five of the nine patients, cerebral ischemia occurred between 20 and 30 minutes after cross-clamping; all occurred during relative intraoperative hypotension (average reduction of 35 mm Hg in the systolic pressure). All awake patients in whom ischemic symptoms developed immediately regained and maintained normal neurologic function with shunt placement. Five of 26 patients (19%) with contralateral occlusion required a shunt; none had postoperative ischemia. The mean carotid cross-clamp time was 27 minutes. Postoperative (30 day) complications included a 0.5% stroke rate, a 0.5% rate of postoperative transient ischemic attack, a 0.5% rate of worsening of preexisting acute stroke, and a 0.5% rate of myocardial infarction (no deaths). Of the nine patients who had intraoperative ischemic changes, none had a postoperative neurologic deficit; the three patients who had postoperative neurologic changes had no intraoperative ischemic symptoms.
CEA with regional anesthesia allows continuous neurologic monitoring and can be performed safely even when contralateral occlusion coexists; intraoperative shunting for ischemia is necessary in 4.5% of all cases and in 19% of patients with contralateral occlusion. Intraoperative ischemia was flow-related in our patients; it occurred early from ipsilateral carotid clamping and late from reduced collateral flow as a result of hypotension. Monitoring should be continued throughout cross-clamping to identify late cerebral ischemia. Postoperative cerebral ischemia is not associated with intraoperative ischemia, if corrected.
关于在颈动脉内膜切除术（CEA）期间识别脑缺血的最佳技术存在争议。区域麻醉允许持续评估神经功能，因此有助于确定脑缺血的发生率、发生时间和原因。
通过回顾在68个月期间接受区域麻醉下CEA的连续患者的手术报告、医院病历和门诊记录，确定CEA期间以及术后长达30天内任何神经事件的发生时间和临床表现。
200例患者接受了CEA；适应症为25%的无症状狭窄>60%，52%的短暂性脑缺血发作伴狭窄>50%，23%的既往卒中伴狭窄>50%。8例患者（4%）因非缺血性原因转为全身麻醉。在其余192例患者中，183例（95.5%）接受了区域麻醉且未使用分流管的手术，2%发生脑缺血并进行了分流管置入，2.5%发生脑缺血，转为全身麻醉并进行了分流管置入。9例患者在颈动脉夹闭后出现脑缺血，表现为4例意识丧失，2例意识模糊，1例构音障碍和意识模糊，2例对侧肌力下降。9例患者中有4例在夹闭后1分钟内出现即刻脑缺血；这4例均进行了分流管置入。9例患者中有5例在夹闭后20至30分钟出现脑缺血；均发生在术中相对低血压期间（收缩压平均降低35 mmHg）。所有出现缺血症状的清醒患者在置入分流管后立即恢复并维持了正常神经功能。26例对侧闭塞患者中有5例（19%）需要分流管；均无术后缺血。平均颈动脉夹闭时间为27分钟。术后（30天）并发症包括0.5%的卒中发生率、0.5%的术后短暂性脑缺血发作发生率、0.5%的既往急性卒中恶化发生率和0.5%的心肌梗死发生率（无死亡）。9例术中出现缺血性改变的患者均无术后神经功能缺损；3例术后出现神经功能改变的患者术中无缺血症状。
区域麻醉下的CEA允许持续的神经监测，即使在对侧闭塞并存时也能安全进行；所有病例中有4.5%、对侧闭塞患者中有19%在术中因缺血需要进行分流管置入。我们的患者术中缺血与血流相关；早期发生于同侧颈动脉夹闭，晚期发生于低血压导致的侧支血流减少。在整个夹闭过程中应持续监测以识别晚期脑缺血。如果得到纠正，术后脑缺血与术中缺血无关。
