1、Anesthetic Management of Cerebrovascular Disease Carotid Endarterectomy,Daniel J.Cole,M.D.Phoenix, Arizona 翻译：福建医科大学附属协和医院麻醉科规培住院医师：曾燕,脑血管疾病颈动脉内膜切除术的麻醉管理,Introduction,Stroke （中风）is the third leading cause of death. carotid artery disease（劲动脉疾病） is a significant anesthetic issue （麻醉问题）for patients ov
2、er 50 years of age. A stroke occurs due to occlusive or hemorrhagic conditions. Occlusive cerebrovascular disease can be thrombotic, embolic, or stenotic(血栓，栓塞或狭窄)in origin.(闭塞性或出血性中风的发生是由于闭塞性脑血管疾病，血栓，栓塞或起源于狭窄) Patients with a history of prior stroke （既往中风史）or transient ischemic attack（短暂性脑缺血发作） hav
3、e an increased risk of recurrent perioperative stroke （围术期再次中风的危险）.,简介,Major symptoms of carotid artery disease include changes in vision, headache, changes in speech, or facial(发热) and extremity(四肢) weakness. Signs(体征) suggestive of carotid artery disease include a high-pitched bruit (高亢的杂音)at the
4、origin(起源) of the internal carotid artery, increase in size and pulsation（强度） of the ipsilateral (同侧)superficial temporal artery（颞浅动脉）, and changes in the retinal examination（眼底检查）. Confirmation（确诊） of carotid artery disease is achieved by vascular imaging which may include ultrasound, MR angiograph
5、y, or catheter angiography.（颈动脉疾病的确认是通过血管成像，其中可能包括超声，磁共振血管造影或导管造影）,Introduction,Presently, there is insufficient （不足的）information to regarding the timing of surgery （手术时机） following an ischemic episode（缺血性发作）. Data（数据） suggests there is a small but real increase in morbidity（发病率） if surgery is perfo
6、rmed shortly after the onset of symptoms（症状）.（数据表明，如果进行手术后不久出现症状，有一个小，但真正的发病率增加） Risk may be associated with the presence（存在） of a low density（低密度） lesion （病变）on CT scan, vascular territory（血管壁内） of the infarct（梗塞）, brain shift（脑组织移位）, and level of consciousness（意识）.,Carotid Artery Revascularization
7、（颈动脉再灌注）,Carotid endarterectomy (CEA) （颈动脉内膜切除术）was introduced in 1954 as treatment for occlusive（闭塞性） carotid artery disease. Efficacy（疗效） data on CEA was limited until the 1990s. Analysis of three trials has demonstrated that CEA has a marginal（微小） benefit in symptomatic patients with 50%-69% sten
8、osis of the carotid artery, and was of greatest benefit in patients with 70% stenosis.（三项试验分析表明，CEA在狭窄面积为50-69的颈动脉狭窄症状的患者身上收效甚微，在狭窄 70的患者收益最大。）,Carotid Artery Revascularization（颈动脉再灌注）,Stenting(支架植入术) and angioplasty（血管成形术） of the carotid artery (CAS) has been performed for almost two decades. Poten
9、tial （潜在） advantages of CAS include avoiding cranial nerve（颅神经） damage, wound hematoma（伤口血肿）, and general anesthesia（全身麻醉）. The anesthetic technique for this procedure involves（ 涉及）minimal sedation(镇静）. This procedure can cause severe （严重）bradycardia（心动过缓） and hypotension, and can result in cerebral
10、 hyperperfusion（高灌注）.,Anatomic/Physiologic（解剖/生理学） Considerations（注意事项）,Carotid artery disease is typically（通常是） the result of ather-osclerosis（动脉粥样硬化）at the bifurcation（分支） of the common carotid artery（颈总动脉）or the origin（主支） of the internal carotid artery（颈内动脉）. （颈动脉疾病通常是颈内动脉主支和颈总动脉分支粥样硬化的结果） Ische
11、mia is most often embolic in origin but may also have a hemodynamic basis.（ 缺血最常见的起源于栓塞，但可能也有血液动力学基础） There are three phases（阶段） of the response of various cerebral variables（脑变量） to progressive（进展的） carotid artery disease.（颈动脉疾病的进展在脑变量的反应上分三阶段） During ischemia（缺血）, collateral flow（侧支循环） is a corner
12、stone（基础） of cerebral blood flow (CBF) compensation（补偿）.,Anatomic/Physiologic（解剖/生理学） Considerations,The principal pathways of collateral flow are the Circle of Willis（侧支循环的主要途径是Willis环）, extracranial anastomotic channels（颅外吻合通道）, and leptomeningeal （脑膜）communications that bridge “watershed”（分水岭） ar
13、eas between major arteries. During CEA, the risk of ischemia is related to the dependency of the circulation on the ipsilateral（同侧） internal carotid（颈内） artery, and the cerebrovascular（脑血管） reserve（储备） of the contralateral（对侧） hemisphere（半球）.,Preoperative Concerns（术前关注点）,CEA has an inherent（固有） risk
14、 of perioperative（围手术期） stroke and cardiovascular（心血管） events.（CEA存在着围术期中风和心血管事件的固有风险） In symptomatic patients, there is a 6.5% rate of stroke and death associated with CEA; while the reported stroke and death rate for patients with asymptomatic disease is 2.3%. The risk for stroke following CEA is
15、most strongly associated with an active neurologic（神经） process（活动） prior to surgical intervention（手术干预）.,Other factors which have been reported to increase neurological risk include:（其他有报道的增加神经系统风险的因素包括）, hemispheric versus retinal transient ischemic attack（半球与视网膜短暂性脑缺血发作） an urgent procedure（紧急手术）
16、a left sided procedure（左侧手术） ipsilateral ischemic lesion on computerized tomography（电脑断层扫描同侧缺血性病变） contralateral carotid occlusion or poor collaterals（对侧的颈动脉闭塞或者侧支循环差） impaired consciousness（意识障碍） an irregular or ulcerated ipsilateral plaque（不规则或者破溃的同侧斑块）,Medical complications occur about 10% of the
17、 time after CEA and are associated with the following:（CEA后并发症的发生还与下列有关）, Hypertension (HTN) （高血压病）： the incidence（发病率） of a neurologic deficit（神经功能缺损） is greater in patients with uncontrolled（ 未控制的）HTN preoperatively （术前）and postoperative HTN（术后高血压）.（术前未控制的高血压和术后高血压的神经功能缺损的发病率更高） Cardiac（心脏病）： a ca
18、rdiac assessment（心脏评估） is indicated in patients who present for CEA. Diabetes（糖尿病）： data indicate（表明） that CEA can be performed safely in patients with diabetes（糖尿病人可以安全的进行CEA） Renal insufficiency（肾功能不全）： patients with renal insufficiency have an overall（整体）increased（增加） risk for stroke, death, and
19、cardiac morbidity（发病率）, associated with CEA,Monitoring （监控）,Basic Monitoring ：this should include basic ASA monitoring and intra-arterial blood pressure monitoring. （基本监控应包括基础麻醉的监测和动脉内血压监测）CNS Monitoring：no special cerebral monitor is required in awake patients with regional anesthesia.special cereb
20、ral monitor（脑监测） is employed（用于） when general anesthesia（全麻）.,Monitoring （监控）,Electrophysiological（电生理） Monitoring: The 16-channel EEG（脑电图） remains a sensitive indicator（指标） of inadequate（不足） cerebral perfusion（脑灌注）. Ipsilateral（单） or bilateral（双） attenuation（降低） of high frequency amplitude（高频压力） or
21、 development（增长） of low frequency activity seen during carotid cross-clamping is indicative of inadequate cerebral perfusion.Intraoperative neurologic complications have been shown to correlate well with EEG changes indicative of ischemia. （同侧或双侧高频衰减幅度或开发低频活动期间看到颈动脉交叉夹紧是反映脑灌注不足，术中已显示出良好的相关性脑电图改变，预示缺
22、血的神经系统并发症）,Most studies suggest that SSEPs are useful for monitoring cerebral perfusion during cross-clamping and have similar or superior sensitivity and specificity to conventional EEG.(SSEPs在监测夹闭动脉的脑灌注上有类似或优于常规脑电图的敏感性和特异性） Stable anesthesia must be maintained to minimize the influence of anesthet
23、ics on the SSEP amplitude. In general, 50% reduction of amplitude of the cortical component is considered to be a significant indicator of inadequate cerebral perfusion. In contrast to conventional EEG, SSEP monitors the cortex as well as the subcortical pathways in the internal capsule, an area not
24、 reflected in the cortical EEG.（必须维持麻醉平稳麻醉药对体感诱发电位的振幅的影响减到最小。在一般情况下，减少50的振幅皮质成分被认为是脑灌注不足一个重要的指标。与常规脑电图相反，体感诱发电位监测皮层和皮层下通路， 而没有反映在皮层脑电图,Monitoring （监控）,Measurement of Stump（残端）Pressure: Since one important determinant of CBF is perfusion pressure, it seems reasonable to assume that the distal（远端） art
25、erial pressure in the ipsilateral（同侧） hemisphere（半球） during carotid occlusion（颈动脉闭塞） would provide some indication（迹象） of collateral（侧枝的） CBF. Stump pressure involves direct measurement of the retrograde internal carotid artery pressure following occlusion of the more proximal common and external ca
26、rotid arteries.（由于CBF的一个重要的决定因素是灌注压，这似乎是合理的假设，在同侧半球在颈动脉闭塞远端动脉压会提供一些补偿，CBF树桩压力涉及直接测量闭塞的逆行颈内动脉的近端压力和颈外动脉压力）Transcranial Doppler （经颅多普勒超声）(TCD): TCD has been utilized（利用） as a monitoring（监控） tool by measuring blood flow velocity（速度） in the middle cerebral artery（中脑动脉） during CEA. （TCD被用来作为监测工具，通过测量CEA过
27、程中大脑中动脉血流速度）,Anesthetic Management,General anesthesia is preferred in patients with anatomy/pathology that may make the surgical conditions difficult.（全麻是那些在解剖/病理学上有手术困难的患者的首选）One caveat that is often not appreciated regards nitrous oxide. It is very difficult to place a shunt in the carotid artery,
28、 or to release the carotid artery cross-clamp, without exposing the distal cerebral circulation to air bubbles.（需要注意的一点是氧化亚氮是不被推荐的。放置颈动脉分流器或释放颈动脉交叉钳时不暴露前端而使气泡进入到脑循环，这是非常困难的）,Anesthetic Management,Sevoflurane and desflurane have been shown to result in quicker extubation times and recovery profiles a
29、fter CEA, compared to isoflurane, with no significant perioperative difference in cardiac morbidity.（与异氟烷相比，七氟烷和地氟烷被证明CEA术后更快的拔管时间、更好的苏醒质量，而无围术期心脏事件发生率的不同。） Propofol and narcotics may be associated with better hemodynamic stability than isoflurane, and remifentanil/propofol may have less evidence of
30、 myocardial ischemia than isoflurane/fentanyl.（与异氟烷相比，丙泊酚和阿片类可能有更好的血流动力学稳定性，瑞芬太尼/丙泊酚与异氟烷/芬太尼相比可能更少的心肌缺血发生）,Anesthetic Management,A regional technique for CEA requires anesthesia of cervical nerves 2-4. （CEA的区域麻醉需要麻醉颈神经2-4） Superficial cervical plexus block, deep cervical plexus block, epidural anest
31、hesia, straight local, and combinations of these techniques have all been used successfully.（颈浅神经丛阻滞、颈深神经丛阻滞、硬膜外麻醉、单纯局麻或以上技术的结合都被成功的使用过）Until recently, non-randomized studies suggested that the use of a regional technique may be associated with reductions (approximately 50%) in the odds of stroke, d
32、eath, myocardial infarction and pulmonary complications.（直到最近，非随机研究提示区域性技术可能与术后中风、死亡、心肌梗死、肺部并发症的减少（近50%）相关。）,Modalities of Cerebral Protection脑保护的方式,Surgical（外科）： a shunt is placed to maintain CBF during cross-clamping（分流在颈动脉夹闭时用于维持脑血流）. Most often, placement of the shunt is dependent on the data of
33、 a cerebral monitor.（大多数情况下，是否放置分流取决于脑功能监测的数据） A shunt entails the risks of embolization and carotid intimal dissection， and limits surgical exposure. （分流意味着栓塞和颈动脉内膜剥脱的风险，并限制了外科暴露） There is insufficient evidence from randomized controlled trials to support or refute the use of routine or selective s
34、hunting during CEA.（没有足够随机对照实验证据支持或拒绝在CEA中常规或选择性分流）,Physiologic:（生理）1. Hypothermia（低温）-much has been studied about the beneficial（有益） effect of mild hypothermia（低温） on cerebral ischemia（脑缺血）. Accordingly, is the concern that if hypothermia is employed as a cerebral protectant for CEA, many patients
35、may suffer from shivering during recovery; and a consequent increase in myocardial oxygen consumption which may precipitate myocardial ischemia. Thus, routine employment of hypothermia is not recommended for patients undergoing CEA. Conversely, hyperthermia should be avoided.（很多研究已经表明低温对脑缺血的有利，但是，如果
36、采用低温作为CEA术中的脑保护剂，许多患者可出现在恢复过程中寒战发抖以及心肌耗氧量的增加可能诱发心肌缺血，因此，不建议常规对接受CEA的患者进行低温麻醉，相反，应避免高温）,2. Hyperglycemia（高血糖）-should be avoided（避免） and treated（处理） when possible.3. Hypertension（高血压）-during ischemia, autoregulation（自动调节） is impaired and CBF is dependent on perfusion pressure（灌注压）. It is advisable to
37、maintain normal to high arterial pressure in most situations.（缺血过程中，自动调节受损，脑血流是依赖于灌注压力以维持正常的动脉血压，在大多数情况下，这是可取的）4. Hemodilution（血液稀释）-using hemodilution to improve CBF is dependent upon the rationale（原理） that CBF is inversely related to（负相关的） hematocrit（血细胞比容）.（使用血液稀释改善CBF是根据CBF负相关于血细胞比容的原理）5. Carbon
38、 Dioxide（二氧化碳）-normocarbia（正常二氧化碳分压） should be the goal.（必须维持正常的二氧化碳分压）,Modalities of Cerebral Protection,Anesthetics:（麻醉药）1. Barbiturates（巴比妥类药物）-as a whole, the evidence does not support the use of barbiturates as a cerebral protectant for permanent focal ischemia. (总的来说，证据不支持使用巴比妥类药物作为永久性局灶性脑缺血脑保
39、护剂)2. Volatile Anesthetics（挥发性麻醉药）-general anesthesia with isoflurane and sevoflurane is associated with a lower critical CBF (that at which EEG evidence of ischemia was present) compared to halothane and enflurane（与氟烷、安氟醚相比，全身麻醉中使用异氟醚和七氟醚更少出现危险的脑血流（脑电图证实的脑缺血）3. Etomidate（依托咪酯）-etomidate is not reco
40、mmended for use as a cerebral protectant.（依托咪酯，不建议用做脑保护剂）4. Propofol（异丙酚）-the amassed database is not as large as that for barbiturates （数据有限）5. Dexmedetomidine（右美托咪啶）-it should be pointed out that in human volunteers dexmedetomidine decreases CBF but does not increase the incidence of shunt placeme
41、nt during awake CEA（应该指出的是，在人类志愿者，右旋美托咪啶降低脑血流，但是在清醒麻醉下的CEA中不增加分流率）,The Postoperative Period（术后）,Concernsin the immediate postoperative period include:（术后即刻应关注的是：）1. HTN（高血压）-HTN may worsen neurologic outcome by exacerbating the hyperperfusion syndrome with resultant intracerebral hemorrhage（高血压可能加剧高
42、灌注综合征，导致脑出血，使预后恶化）2. Hyperperfusion （高灌注）Normotension should be maintained in patients at risk for hyperperfusion.（有高灌注危险的患者应保持患者正常灌注）3. Hypotension（低血压）-Regional anesthesia may be associated with a higher incidence of postoperative hypotension while general anesthesia is more often associated with
43、postoperative hypertension（区域麻醉可能伴随术后高发生率的低血压，而全麻往往与术后高血压相关）4. Myocardial Infarction（心梗）-the most frequent cause of morbidity and mortality（心梗是发病率和死亡率的最常见的原因，）5. Stroke（中风）-most often embolic in origin.（中风常源于栓塞）,6. Bleeding- airway obstruction has been attributed to neck hematoma that is worsened by
44、 hypertension.（气道阻塞已被归因于高血压恶化导致的颈部血肿） 7. Cranial Nerve Injury -Damage to the recurrent laryngeal nerve may compromise protective reflexes as well as cause airway obstruction. Bilateralinjuries can result in upper airway obstruction.（喉返神经的损伤除了可能引起气道梗阻，还可能损害保护性反射。双侧损伤可能会导致上呼吸道阻塞。）8. Carotid Body Damag
45、e results in reduced ventilatory response to hypoxemia and hypercapnia. Patients undergoing second-side CEA merit close observation.（颈动脉体损伤导致对低氧血症和高碳酸血症的通气反应降低，患者接受第二侧CEA应密切观察。）9. CNS Dysfunction（中枢神经系统功能障碍）,Conclusions,Approximately one third of perioperative strokes are hemodynamic in nature. （围术期
46、中风大约有三分之一源于血流动力学的变化）It is reasonable that tight physiologic management might affect this subset of patients. （严格的生理管理可能影响这一部分患者，这是合理的）Patients who have undergone CEA have increased risk of a perioperative myocardial event. （接受过CEA的患者围术期心肌事件的风险增加）There is no demonstrable advantage of a specific anest
47、hetic technique for patients undergoing CEA.（没有一种特别的麻醉技术对CEA患者有明显的优势） Whichever anesthetic technique is employed, it is imperative that CBF is optimized there is minimal cardiac stress, and that anesthetic recovery is rapid. （无论采用哪种麻醉技术，都要求合适的脑血流和更小的心脏负荷以及更快的苏醒）Additional concerns in the immediate p
48、ostoperative period are tight hemodynamic control.（在术后即刻期间应特别关注严格的血流动力学控制）,Table 2-key points of anesthetic management of CEA.（CEA麻醉管理的关键点）,Indications （适应症） In symptomatic patients, CEA is indicated if stenosis is 70 percent; and for selected patients if the stenosis is 50-69 percent. In asymptomatic patients, the indications are controversial. （在有症状的患者中，狭窄70的患者是手术的适应症，狭窄在50-69可有选择的进行手术。无症状患者的手术适应症是有争议的）,Preoperative Concerns（术前关注点）：Hypertension（高血压） coronary artery disease（冠状动脉疾病） diabetes mellitus（糖尿病） renal insufficiency（肾功能不全） active neurologic process （神经功能的变化）,
