全主动脉弓替换术中顺行性脑灌注时血流变化观察
作者：田良鑫，叶赞凯， 程卫平，杨九光，郑军，孙立忠。
摘要：目的 利用前瞻性随机对照方法比较全主动脉弓替换术中单侧顺行性脑灌注(ASCP)和双侧ASCP时视网膜中央动脉、球后血管血流变化和血S100蛋白浓度变化。方法 16例全主动脉弓替换术患者随机分为单侧ASCP和双侧ASCP组,每组各8例。两组均行术前术后颅脑计算机体层摄影（CT）。术中采用经眼球超声监测视网膜中央动脉及球后血管血流。术中术后动态测定血S100蛋白浓度。结果 两组各有1例出现短暂性神经功能异常。ASCP过程中单侧组右侧视网膜中央动脉可探及血流，左侧视网膜中央动脉不可探及，双侧组两侧视网膜中央动脉均可探及血流。所有患者球后动脉均可探及血流。两组间各阶段血S100蛋白浓度无显著性差异（P0.05）。结论 在基底动脉环完整，存在有效侧支循环条件下，单侧灌注操作较为简便，双侧灌注在ASCP期间两侧脑灌注较为均衡,但两种灌注方法对S100蛋白浓度的影响无显著性差异。
关键词：主动脉；胸外科学；顺行性脑灌注；经眼球超声；S100蛋白。
Orbital Ultrasound and S100 Protein Monitoring during Unilateral and Bilateral Antegrade Selective Cerebral Perfusion in Total Aortic Arch Replacement。
Abstract: OBJECTIVETo compare the serum S100 protein concentration and blood flow in the central retinal artery and retrobular vessels between unilateral and bilateral antegrade selective cerebral perfusion during total aortic arch replacement.METHODS From June 2003 to March 2004, 16 patients who underwent total arch replacement were randomly allocated to one of two methods of brain protection: unilateral antegrade selective cerebral perfusion (unilateral group, n=8 ) or bilateral antegrade cerebral perfusion (bilateral group, n=8). Preoperative and postoperative brain CT scans were performed. During the operation, the blood flow in the central retinal artery and retrobular vessels was monitored with orbital ultrasound. Serum S100 protein was assayed before skin incision, immediately after thoracotomy, 30 minutes after the cardiopulmonary bypass, as well as 6 hours, 24 hours and 48 hours post—operatively. RESULTS All patients survived and were discharged from hospital. No new brain infarction occurred. Transient neurologic dysfunction occurred in 1 patient from each group. During antegrade selective cerebral perfusion, blood flow in the right central retinal artery was detectable in the unilateral group, butnot detectable in the left central retinal artery. In the bilateral group, the blood flow on both sides was detectable during antegrade selective cerebral perfusion. The blood flow in the retrobular vessels was detectable in all of the patients during antegrade selective cerebral perfusion. There were no intergroup differences in serum S100 protein concentration in all phases (P0.05). CONCLUSION Both methods of brain protection had a similar effect upon S100 protein concentration providing the circle of Willis was patent and collateral flow was adequate. Blood flow in bilateral antegrade selective cerebral perfusion was more uniform, whilst unilateral antegrade selective cerebral perfusion has the advantage of simplicity.
Key words：aorta; thoracic surgery; antegrade selective cerebral perfusion; orbital ultrasound; S100 protein。
中枢神经系统损伤一直是主动脉弓部手术中最突出的并发症和致死因素，对术后脑损伤的研究也一直没有停止过。深低温停循环技术曾广泛地应用于主动脉弓部手术中，但中枢神经耐受缺血的能力限制了停循环的安全时限。逆行性脑灌注（RCP）及顺行性脑灌注（ASCP）便先后被用于主动脉弓部手术的脑保护。对于两种灌注方法孰优孰劣尚有争议，但随着研究的进一步深入，许多证据表明RCP不能提供足够的营养物质［1］，越来越多的学者采用ASCP代替逆行性脑灌注用于主动脉弓部手术中的脑保护［2］。ASCP可分为单侧ASCP及双侧ASCP两类。双侧ASCP管道多，影响术野显露，操作复杂。单侧灌注操作简便，但单侧ASCP能否达到双侧ASCP的脑保护效果尚无定论。本研究目的在于比较全主动脉弓替换术中单侧ASCP和双侧ASCP时视网膜中央动脉、球后血管血流变化、血S100蛋白浓度变化，为进一步评价单侧ASCP和双侧ASCP奠定基础。
1 对象与方法。
1.1 对象 2003年6月至2004年3月,阜外医院外科共行全主动脉弓替换手术50例，有以下情况之一者被排除于本研究之外：(1)颈部血管超声发现一侧颈内动脉或椎动脉有50%以上狭窄。(2)经颅多普勒（TCD）检查发现基底动脉环有中度以上狭窄，无有效的侧支循环。(3)急诊患者。(4)有脑血管病史。共纳入患者16例，均为男性，随机分为单侧组及双侧组，每组各8例。单侧组采用经右腋动脉插管单侧ASCP，双侧组采用经右腋动脉和左颈总动脉插管双侧ASCP。两组临床资料差异无显著性（表1）。所有患者均行术前及出院前颅脑CT检查。表1 两组临床资料比较（略）。
1.2 手术及ASCP方法。
所有患者采用统一的静脉及吸入复合麻醉方案。在右腋动脉置入22～24F动脉插管，从右房插入二阶梯静脉引流管，建立体外循环(CPB)，全身降温。鼻咽温度降至20℃时，取头低位，降低流量至10ml/(kg・min)后单侧灌注组分别阻断主动脉弓部各分支，经右腋动脉进行ASCP。双侧灌注组则暂停CPB，经主动脉弓腔内向左颈总动脉插入20F动脉插管, 阻断主动脉弓部除左颈总动脉以外的分支，经右腋动脉及左颈总动脉行双侧ASCP。两组ASCP流量均为10ml/(kg・min)。所有患者均采用4分支人工血管重建主动脉弓部。