劉 暢,陳 楊,朱悉煜,王東進(jìn)
·臨床研究·
深低溫停循環(huán)選擇性腦灌注最小安全流量的臨床研究
劉 暢,陳 楊,朱悉煜,王東進(jìn)
目的總結(jié)主動(dòng)脈夾層患者深低溫停循環(huán)(DHCA)順行選擇性腦灌注(ASCP)流量的選擇,探討選擇性腦灌注流量的最小安全范圍,從而減少術(shù)后神經(jīng)系統(tǒng)并發(fā)癥的發(fā)生。方法選擇南京大學(xué)醫(yī)學(xué)院附屬鼓樓醫(yī)院2016年1月至2016年12月Stanford A 型夾層動(dòng)脈瘤患者107例,全組患者均在DHCA+ASCP體外循環(huán)方式下行主動(dòng)脈全弓置換+支架象鼻手術(shù),術(shù)前頸動(dòng)脈超聲檢查結(jié)果示頸動(dòng)脈中重度狹窄患者和/或合并有腦血管疾病病史被排除研究之外。根據(jù)術(shù)中不同的ASCP流量分為 3 ml/(kg·min)小流量組(M 組 )、 5 ml/(kg·min)低流量組(D 組 )。術(shù)中應(yīng)用近紅外光譜(NIRS)監(jiān)測儀連續(xù)監(jiān)測DHCA+ASCP流量下5個(gè)時(shí)間點(diǎn)。分別為:麻醉誘導(dǎo)后(T1)、阻斷升主動(dòng)脈后(T2 )、恢復(fù)循環(huán)10 min(T3)、開放升主動(dòng)脈10 min(T4)和停體外循環(huán)后5 min(T5)。記錄雙側(cè)局部大腦氧飽和度(rSO2)數(shù)值、靜脈血乳酸含量及術(shù)后恢復(fù)情況。結(jié)果所有患者無術(shù)后嚴(yán)重神經(jīng)系統(tǒng)并發(fā)癥發(fā)生。兩組患者ASCP時(shí)間、主動(dòng)脈阻斷時(shí)間、 轉(zhuǎn)機(jī)時(shí)間、手術(shù)時(shí)間、轉(zhuǎn)中最低溫度、術(shù)中輸血量、各個(gè)時(shí)間點(diǎn)乳酸濃度差異無統(tǒng)計(jì)學(xué)意義,兩組患者T3、T4兩個(gè)時(shí)間點(diǎn)rSO2變化有統(tǒng)計(jì)學(xué)差異,M組低于D組(P<0.05)但M組的rSO2仍在安全范圍內(nèi),可維持患者腦氧代謝,其余各時(shí)間點(diǎn)rSO2變化無統(tǒng)計(jì)學(xué)差異、患者術(shù)后機(jī)械輔助通氣時(shí)間、監(jiān)護(hù)室停留時(shí)間、術(shù)后二次開胸止血時(shí)間差異均無統(tǒng)計(jì)學(xué)意義。結(jié)論主動(dòng)脈夾層行DHCA+ASCP,在一定時(shí)間內(nèi)3~5 ml/(kg· min)的腦灌注流量時(shí)rSO2在可接受的范圍內(nèi)。能夠?yàn)榇竽X提供足夠的血流,滿足大腦氧代謝所需,均能獲得滿意的腦保護(hù)效果。
深低溫停循環(huán);選擇性腦灌注;腦血氧飽和度;體外循環(huán)
自從1975年,Griepp首次利用低溫技術(shù)腦保護(hù)完成弓部手術(shù)以來,涉及主動(dòng)脈弓部的主動(dòng)脈手術(shù)多采用深低溫停循環(huán)(deep hypothermic circulatory arrest,DHCA)技術(shù)來實(shí)現(xiàn)腦及其他臟器的保護(hù)。臨床研究表明腦組織的氧耗隨著溫度的降低而相應(yīng)降低,18℃時(shí)腦的安全時(shí)限為30~60 min[1],雖然深低溫可以降低腦代謝率,從而減少延長腦缺血的耐受時(shí)間,但是包括腦組織缺血缺氧、體外循環(huán)引起炎癥反應(yīng)等因素,所造成的神經(jīng)系統(tǒng)損傷、凝血功能異常、器官功能障礙、肺損傷等并發(fā)癥也引起較多關(guān)注[2]。因此,結(jié)合DHCA不同的腦保護(hù)方式應(yīng)運(yùn)而生,目前大多數(shù)中心仍采用DHCA+順行選擇性腦灌注(antegrade selective cerebral perfusion,ASCP)的方式行腦保護(hù),常用的ASCP流量為5~10 ml/(kg·min)。但是較高流量的ASCP,會(huì)導(dǎo)致腦水腫及顱內(nèi)壓腦升高增加術(shù)后神經(jīng)并發(fā)癥的發(fā)生[3],有動(dòng)物實(shí)驗(yàn)表明3 ml/(kg·min)ASCP流量能滿足腦需氧量[4]。本研究旨在探討腦保護(hù)所需的最小安全灌注流量。
1.1一般資料 回顧分析南京鼓樓醫(yī)院2016年1月至2016年12月收治Stanford A型主動(dòng)脈夾層動(dòng)脈瘤擇期手術(shù)患者107例。排除合并有腦血管疾病病史和術(shù)前頸動(dòng)脈超聲檢查結(jié)果示頸動(dòng)脈中重度狹窄患者。全部患者均擇期行DHCA+ASCP主動(dòng)脈全弓置換+支架象鼻手術(shù)。按照腦灌注流量不同分為:3 ml/(kg·min)小流量組(M 組 )41例;5 ml/(kg·min)低流量組(D 組 )66例。
1.2手術(shù)和麻醉方法 兩組患者均采用DHCA+ASCP的體外循環(huán)方式行主動(dòng)脈全弓置換+支架象鼻手術(shù),其中M組同期行Bentall術(shù) 11例,Wheat術(shù) 2例,冠狀動(dòng)脈旁路移植術(shù)3例,D組同期行Bentall術(shù) 24例,Wheats術(shù)5例,冠狀動(dòng)脈旁路移植術(shù)4例(表1)。采用靜脈吸入復(fù)合麻醉,監(jiān)測ECG、左側(cè)橈動(dòng)脈壓、左足背動(dòng)脈壓、脈搏氧飽和度、中心靜脈壓、鼻咽溫和直腸溫及混合靜脈血氧飽和度、紅細(xì)胞比容及血漿膠體滲透壓等。
1.3體外循環(huán)管理 采用Sorin C5型體外循環(huán)機(jī)、泰爾茂成人膜式氧合器。預(yù)充液采用復(fù)方乳酸鈉林格注射液2 000 ml全晶體液預(yù)充,機(jī)器內(nèi)加入肝素2 000 U。應(yīng)用含血停搏液(晶體∶血液為1∶4)行心肌保護(hù)。動(dòng)脈插管為右側(cè)腋動(dòng)脈插管,根據(jù)實(shí)際情況增加股動(dòng)脈插管,靜脈插管右心房和/或上、下腔靜脈建立體外循環(huán),降溫至鼻咽溫32℃,阻斷升主動(dòng)脈,經(jīng)主動(dòng)脈根部或切開升主動(dòng)脈直接經(jīng)冠狀動(dòng)脈開口灌注心臟停搏液,術(shù)中采用順行灌注+逆行灌注相結(jié)合的灌注方式行心肌保護(hù)。繼續(xù)降溫,當(dāng)鼻咽溫降至18~21℃時(shí),行DHCA+ASCP。腦灌注流量為3~5 ml/(kg·min),近端分別阻斷無名動(dòng)脈、左頸總動(dòng)脈及左鎖骨下動(dòng)脈。主動(dòng)脈弓部手術(shù)操作完成后分次、20 ml/(kg·min)、30 ml/(kg·min)、40 ml/(kg·min)逐步提升流量至全流量恢復(fù)全身循環(huán)。全流量灌注10~15 min、混合靜脈血氧飽和度>75%時(shí),開始復(fù)溫,期間需維持直腸溫度與水箱溫差<10℃,鼻咽溫與直腸溫度差<5℃,鼻咽及直腸溫恢復(fù)至36.5℃停止體外循環(huán)。充分止血后魚精蛋白中和。拔除動(dòng)脈靜脈插管。
1.4NIRS監(jiān)測 麻醉后將近紅外光譜(near-infrared spectroscopy,NIRS)(FORE-SIGHT,美國CAS Medical Systems,Inc)探頭置于患者雙側(cè)前額,使用頭環(huán)將探頭固定。分別于麻醉誘導(dǎo)后(T1)、阻斷升主動(dòng)脈后(T2)、恢復(fù)循環(huán)10 min(T3)、開放升主動(dòng)脈10 min(T4)和停體外循環(huán)后5 min(T5)時(shí)記錄雙側(cè)腦血氧飽和度(regional cerebraloxygention,rSO2)數(shù)值。并且記錄各個(gè)時(shí)間點(diǎn)靜脈血乳酸含量及術(shù)后恢復(fù)情況。
兩組患者術(shù)前基本資料包括:性別、年齡、體重、術(shù)前心臟功能和合并疾病等差異均無統(tǒng)計(jì)學(xué)意義(P>0.05),見表1。
兩組患者ASCP時(shí)間、主動(dòng)脈阻斷時(shí)間、轉(zhuǎn)機(jī)時(shí)間、手術(shù)時(shí)間、轉(zhuǎn)中最低溫度、乳酸濃度差異無統(tǒng)計(jì)學(xué)意義(P>0.05),見表2。
rSO2各時(shí)點(diǎn)無統(tǒng)計(jì)學(xué)差異(P>0.05), 比較兩組患者各時(shí)點(diǎn)rSO2,其中T1、T2、T5三個(gè)時(shí)間點(diǎn)rSO2差異無統(tǒng)計(jì)學(xué)意義(P>0.05),T3、T4兩個(gè)時(shí)間點(diǎn)rSO2差異有統(tǒng)計(jì)學(xué)意義(P<0.05),見表3。
兩組患者術(shù)后機(jī)械輔助通氣時(shí)間、監(jiān)護(hù)室停留時(shí)間、二次開胸止血差異均無統(tǒng)計(jì)學(xué)意義(P>0.05),見表4。
M組2例患者死亡,其中1例出現(xiàn)循環(huán)功能衰竭,1例肺部感染。D組4例患者死亡,其中3例出現(xiàn)循環(huán)功能衰竭,1例出現(xiàn)雙下肢缺血。其余患者均康復(fù)出院,均未出現(xiàn)嚴(yán)重神經(jīng)系統(tǒng)并發(fā)癥。
表1 兩組患者術(shù)前資料及術(shù)中合并手術(shù)比較
注:COPD:慢性阻塞性肺疾??;CABG:冠狀動(dòng)脈旁路移植術(shù)。
表2 兩組患者術(shù)中情況比較
表3 各時(shí)點(diǎn)雙側(cè)rSO2值比較
表4 術(shù)后機(jī)械輔助通氣時(shí)間、監(jiān)護(hù)室停留時(shí)間、二次開胸止血比較
在深低溫的條件下,應(yīng)間斷行腦灌注,為腦組織提供氧供。即ASCP腦保護(hù)可有效的延長DHCA時(shí)間。有研究表明少量的腦血流也會(huì)在保護(hù)中樞神經(jīng)系統(tǒng)功能上起一定的作用。最低只需 5~10 ml/(kg·min)的腦灌注流量即可起到保護(hù)大腦的作用[5]。因此,對(duì)主動(dòng)脈弓部手術(shù)的患者,一般常規(guī)選擇DHCA+ASCP行腦保護(hù)。但是DHCA+ASCP會(huì)給患者帶來腦水腫等神經(jīng)系統(tǒng)的損傷,到底多大的流量能夠即安全的實(shí)現(xiàn)腦保護(hù),同時(shí)能夠最小程度的腦損傷,目前仍沒有定論,有文獻(xiàn)報(bào)道動(dòng)物實(shí)驗(yàn)3~10 ml/(kg·min)的腦灌注流量即能滿足腦需氧量[6]。筆者通過總結(jié)本中心主動(dòng)脈夾層手術(shù)DHCA時(shí)的不同ASCP流量選擇,探討最小安全ASCP流量,以期減少術(shù)后神經(jīng)系統(tǒng)并發(fā)癥的發(fā)生。
rSO2能反應(yīng)大腦氧代謝的供需平衡,尤其是在涉及主動(dòng)脈弓部手術(shù)的主動(dòng)脈夾層患者中,ASCP更需要能夠反映氧代謝的指標(biāo)[7]。而有研究報(bào)道腦血氧飽和度儀的使用能夠?yàn)樾g(shù)中神經(jīng)系統(tǒng)的動(dòng)態(tài)變化提供明確的指征,術(shù)中及時(shí)調(diào)整手術(shù)方案,進(jìn)行腦保護(hù)相關(guān)方面的治療對(duì)于術(shù)后認(rèn)知功能障礙的減少、減少術(shù)后監(jiān)護(hù)室滯留時(shí)間和住院時(shí)間提供了一定的依據(jù)[8]。主動(dòng)脈夾層術(shù)后中風(fēng)的比例約為10%,90%是因?yàn)轭i動(dòng)脈的狹窄或者腋動(dòng)脈插管導(dǎo)致的動(dòng)脈內(nèi)膜的翻轉(zhuǎn)[9],另外術(shù)中、術(shù)后血壓劇烈的波動(dòng)導(dǎo)致的血栓、斑塊、內(nèi)膜片的脫落都會(huì)引起rSO2數(shù)值的劇烈變化。而心臟術(shù)后發(fā)生中風(fēng)的比例約為5%,平均發(fā)生在術(shù)后1.5天,大多數(shù)發(fā)生在右側(cè)大腦半球,且為梗死性[10]。所以術(shù)中根據(jù)rSO2的監(jiān)測對(duì)術(shù)中腦缺血尤其是右側(cè)大腦半球的判斷有明確的意義。rSO2正常值為55%~75%,術(shù)中連續(xù)的監(jiān)測及各個(gè)時(shí)間段的對(duì)比有明確的意義。
本研究中各個(gè)時(shí)間點(diǎn),全組患者雙側(cè)大腦rSO2值均處于正常范圍之內(nèi),術(shù)后無嚴(yán)重神經(jīng)系統(tǒng)并發(fā)癥發(fā)生。不同腦灌注流量比較,rSO2值均隨著手術(shù)的進(jìn)行即溫度的變化而變化,開始手術(shù)降溫至深低溫選擇性腦灌注,rSO2值呈上升趨勢,DHCA結(jié)束開始復(fù)溫至手術(shù)結(jié)束,rSO2值呈下降趨勢,其中體外循環(huán)前(T1)、升主動(dòng)脈阻斷后10 min(T2)、停機(jī)后5 min(T5)三個(gè)時(shí)間點(diǎn)rSO2值的變化趨勢差異并無統(tǒng)計(jì)學(xué)意義?;謴?fù)循環(huán)10 min(T3)、開放升主動(dòng)脈10 min(T4),兩個(gè)時(shí)間點(diǎn)rSO2值的變化趨勢差異存在統(tǒng)計(jì)學(xué)意義。但3 ml/(kg·min)的小流量組rSO2值仍然處于安全閾值范圍以上,提示大腦血液供應(yīng)仍然充足,能夠滿足大腦氧的代謝需求。本研究同時(shí)觀察圍術(shù)期兩組患者血漿乳酸水平,各時(shí)間點(diǎn)靜脈血乳酸值并無差異,均在可接受的范圍內(nèi),提示3 ml/(kg·min)較5 ml/(kg·min)沒有增加腦的無氧代謝。本研究中對(duì)合并有腦血管疾病病史或術(shù)前頸動(dòng)脈超聲檢查結(jié)果示頸動(dòng)脈中重度狹窄患者被排除在該研究之外。不足之處是術(shù)前未對(duì)患者進(jìn)行大腦Willis環(huán)的完整性進(jìn)行評(píng)估,但術(shù)中無患者存在雙側(cè)rSO2值的顯著差異。
本研究顯示,通過DHCA+ASCP的體外循環(huán)方式行主動(dòng)脈全弓置換+支架象鼻手術(shù)治療Stanford A 型夾層動(dòng)脈瘤患者時(shí),除常規(guī)通過左側(cè)撓動(dòng)脈壓力間接監(jiān)測腦灌注壓力外,還可以通過 NIRS持續(xù)監(jiān)測提供的rSO2值來判斷大腦氧供情況。在一定時(shí)間內(nèi) 3~5 ml/(kg·min)的腦灌注流量能夠?yàn)榇竽X提供足夠的血流, 滿足大腦氧代謝所需,均能獲得滿意的腦保護(hù)效果。
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Minimalsafeperfusionflowofselectivecerebralperfusionduringdeephypothermiccirculatoryarrest
Liu Chang, Chen Yang, Zhu Xi-yu, Wang Dong-jin
DepartmentofThoracicCardiacSurgery,GulouHospital,Nanjing210008,China
WangDong-jinEmail:gldjw@163.com
ObjectiveTo identify whether a minimal perfusion flow of selective cerebral perfusion (SCP) during deep hypothermic circulatory arrest (DHCA) was still safe in the surgery of aortic dissection (AD) patients, and to evaluate. The protective effects of it on decreasing neurological complications after surgery.MethodsA retrospective analysis of 107 patients with Stanford type A aortic dissection in our center since Jan. 2016 to Dec. 2016 was performed. Patients with moderate or severe carotid artery occlusion or cranial vascular diseases were excluded by ultrasound examination. All patients enrolled were
total arch replacement and frozen elephant trunk implantation during surgery accompanied with DHCA and SCP. We divided all patients into two groups, M group (3 ml/(kg·min)) and D group (5 ml/(kg·min)), according to the perfusion flow. Near infrared reflectance spectroscopy (NIRS) was settled to evaluate bilateral cerebral oxygen saturation (rSO2) continuously. Meanwhile, lactate levels were also recorded at several time points during surgery, such as after anesthesia induction (T1), after aortic cross clamp (ACC) (T2), 10 min after circulatory restoration (T3), 10 min after ACC releasing (T4) and 5 min after cardiopulmonary bypass (CPB) (T5).ResultsAll patients enrolled in our study were received DHCA and SCP during operations, and none of them were suffered from severe neurological complications. There were no significant differences in perfusion time, ACC time, CPB time and operation time. Also, no differences were found among lactate levels, mechanical ventilation time, intensive care unit duration and post-operative complications. We only found that the levels of rSO2were a bit lower in M group than those in D group at T3 and T4 time points (P<0.05). However, the value of rSO2in M group was still safe for patients to maintain cerebral oxygen metabolism.ConclusionIt is acceptable that minimal perfusion flow (3 ml/(kg·min)) is still safe during DHCA. Moreover, it can provide enough flow and ensure oxygen metabolism to meet the requirement of cerebral protection.
Deep hypothermic circulatory arrest; Antegrade selective cerebral perfusion; Cerebral oxygen saturation; Extracorporeal circulation
10.13498/j.cnki.chin.j.ecc.2017.04.04
210008 南京,南京大學(xué)醫(yī)學(xué)院附屬鼓樓醫(yī)院心胸外科
王東進(jìn),Email:gldjw@163.com
2017-06-19)
2017-08-08)