ScvO2的临床意义

ScvO2的临床意义内容氧供与氧耗SvO2与ScvO2ScvO2的临床应用氧供与氧耗15vol%=15ml/dl5vol%=5ml/dl氧供DO2与氧耗VO2DO2=CaO2×CO=(1.34×SaO2×Hb+0.0031×PaO2)×CO=1.34×SaO2×Hb×COVO2=(CaO2-CvO2)×CO=(SaO2-SvO2)×1.34×Hb×COSvO2=SaO2-VO2/(1.34×Hb×CO)呼吸血红蛋白循环(Fick方程)氧摄取EO2EO2=VO2/DO2EO2=(SaO2-SvO2)/SaO2当SaO2=100%时：EO2=1-SvO2全身EO2=1-75%=25%各组织EO2不同，其相应之静脉氧饱和度不同SvO2=1-EO2氧供氧耗失衡SvO2降低或增加无氧代谢组织缺氧乳酸生成影响SvO2的因素75%-+DO2应激发热寒战躁动疼痛呼吸做功VO2CO(心衰、低容量）Hb（贫血、出血）SaO2（缺氧、呼衰）DO2CO（液体复苏、正性肌力）Hb（输血）SaO2（氧疗）VO2低体温镇静镇痛麻醉机械通气氧摄取（分流、细胞死亡）SvO2的界值PinskyMR,ManceboJ,Appliedphysiologyinintensivecare.ScvO2与SvO2ScvO2与SvO2ScvO2与SvO2SvO2由肺动脉导管测得反映全身的氧耗量正常值：75%ScvO2由中心静脉（上腔静脉）导管测得反映脑及上半身的氧耗量正常值：72%测定方法连续监测光纤导管或光纤中心静脉导管间断测定中心静脉血气正常各组织器官的静脉氧饱和度PinskyMR,ManceboJ,Appliedphysiologyinintensivecare.休克时？ScvO2与SvO2的相关性CharalambosLadakisPavlosMyrianthefsAndreasKarabinisetal.CentralVenousandMixedVenousOxygenSaturationinCriticallyillpatients,Respairation,2001;68279-285LinearcorrelationofpairedScvO2andSvO2measurementsfor296pairedsamplesScvO2increasesby0.87%foreveryunitincreaseinSvO2ScvO2与SvO2的相关性DueckMHetal.Anesthesiology2005;103:249–57MožinaandPodbregarCriticalCare2010,14:R42thMožinaandPodbregarCriticalCare2010,14:R42MožinaandPodbregarCriticalCare2010,14:R42MožinaandPodbregarCriticalCare2010,14:R42SvO2与ScvO2的一致性绝对值相差5~18%ScvO2的临床应用休克中的应用VO2DO2ScvO2/SvO2乳酸休克的本质是组织缺氧和氧代谢障碍，最终结果是MODS。液体复苏、及早纠正氧供与氧耗的失衡、降低组织缺氧程度至关重要。急诊患者的复苏多数（31例/36例）存在休克的危重患者经初期复苏至正常生命体征后乳酸继续升高(2mmol/L)，ScvO2仍低于正常(65%)，提示存在无氧酵解和氧债。这些患者进一步治疗后乳酸下降（4.6±3.8to2.6±2.5,p0.05)，ScvO2升高（52±18to65±13%,p0.05)ScvO2能作为初期复苏后指导休克治疗的指标RadyMY,RiversEP,NovakRM:ResuscitationofthecriticallyillintheED:responsesofbloodpressure,heartrate,shockindex,centralvenousoxygensaturation,andlactate.AmJEmergMed1996,14:218-225.重症感染与感染性休克中的应用1368·1377NEnglJMed,Vol.345,No.19·November8,2001早期目标指导治疗（EGDT）研究结果——死亡率RiversE,NguyenB,HavstadS,eta1．Earlygoaldirectedtherapyinthetreatmentofseveresepsisandsepticshock.NEngJMed,2001,345:1368—1377.进行ScvO2监测，达到EGDT目标，可使患者病死率下降16%（46.5%vs30.5%）。低ScvO2的预后差2012“拯救脓毒症运动”指南——早期复苏目标MAP≥65mmHgCVP8~12mmHg,机械通气12~15mmHg尿量≥0.5ml/kg/hScvO2≥70%orSvO2≥65%感染性休克高ScvO2的预后单因素分析结果存活组与死亡组的ScvO2该研究共纳入4家医院急诊科脓毒症患者619名，按EDGT复苏方案治疗，据ScvO2水平分为三组：低ScvO2组(＜70%)、正常ScvO2组(71~89%)、高组(90~100%)。比较住院死亡率并进行多因素分析0%5%10%15%20%25%30%35%normoxiahypoxiahyperoxiamortality23%25%31%初始ScvO2与死亡率(81/351)(56/223)(14/45)25/6296/46531/92ScvO2在ACS中的应用该研究纳入患者43名，为收住CCU的急性冠脉综合征（ACS）并急性肺水肿或心源性休克患者，测定入室时、24h、48h的中心静脉和外周动脉血气，主要终点为致死性事件，次要终点为住院全因死亡率ActaCardiolSin2008;24:12633结果：存活组与死亡组ScvO2的差异有显著性ActaCardiolSin2008;24:12633所有患者ScvO2、SaO2的变化存活患者ScvO2的变化ActaCardiolSin2008;24:12633创伤患者的评估Lowcentralvenoussaturationpredictspooroutcomeinpatientswithbraininjuryaftermajortrauma:aprospectiveobservationalstudyAlessandroDiFilippo*1,ChiaraGonnelli1,LuciaPerretta1,Rosariopina1,MarcoChiostri2,GianFrancoGensini2andAdrianoPeris1ScandinavianJournalofTrauma,ResuscitationandEmergencyMedicine2009,17:23ScandinavianJournalofTrauma,ResuscitationandEmergencyMedicine2009,17:23ScvO2≤65%的患者住院时间延长，死亡率明显增加急诊插管对重症患者ScvO2的影响15minHernandezetal.CriticalCare2009,13:R63Hernandezetal.CriticalCare2009,13:R63插管改善ScvO2的机制插管前预充纯氧，溶解氧增加，氧供提高插管时镇静与肌松使氧摄取减少而降低氧耗初始机械通气减轻了过度通气，使pH升高而使氧离曲线右移，利于氧释放围术期ScvO2的应用患者资料单因素分析Aftermultivariateanalysis,meanScvO2value(OR1.23[95%CI1.01to1.50],p=0.037),hospitalLOS(OR0.75[95%CI0.59to0.94],p=0.012),andSAPSII(OR0.90[95%CI0.82to0.99],p=0.029)wereindependentlyassociatedwithpostoperativecomplications.多因素分析低ScvO2与术后并发症相关P=0.004TheoptimalvalueofmeanScvO2fordiscriminatingbetweenpatientswhodidordidnotdevelopcomplicationswas73%(sensitivity72%,specificity61%)ScvO2与乳酸在感染性休克中应用比较Jones的研究显示：在感染性休克的早期目标性治疗中，乳酸清除率达标与ScvO2达标，两组的住院死亡率无差别【25%（17~30%）vs17%（11~24%）】。JonesAEetal.JAMA.2010February24;303(8):739–746ScvO2与容量反应性大循环指标：血压、心率、尿量、CVPCO、CIPPVSVVScvO2?ScvO2AsaMarkertoDefineFluidResponsivenessMethods:Atotalof30patientsrequiringVEwereincludedinthisprospectivecohortstudy,allequippedwithradialarteriallineandpulmonaryarterycatheters.CI,mixedvenousoxygensaturation(SvO2)andScvO2weremeasuredbeforeandafterVE.CI,SvO2,andScvO2changesaftervolumewereanalyzedusinglinearregression.ReceiveroperatingcharacteristicscurveanalysiswasusedtotesttheirabilitytodistinguishRandNRMethods:Atotalof30patientsrequiringVEwereincludedinthisprospectivecohortstudy,allequippedwithradialarteriallineandpulmonaryarterycatheters.CI,mixedvenousoxygensaturation(SvO2)andScvO2weremeasuredbeforeandafterVE.CI,SvO2,andScvO2changesaftervolumewereanalyzedusinglinearregression.ReceiveroperatingcharacteristicscurveanalysiswasusedtotesttheirabilitytodistinguishRandNRGiraudR,etal.JTrauma.2011;70:802–807ScvO2AsaMarkertoDefineFluidResponsivenessGiraudR,etal.JTrauma.2011;70:802–807ScvO2AsaMarkertoDefineFluidResponsivenessGiraudR,etal.JTrauma.2011;70:802–807ScvO2AsaMarkertoDefineFluidResponsivenessResults:ScvO2andSvO2variationsafterVE(SvO2)weresignificantlycorrelatedwithCIchanges(CI)afterVE(r0.67andr=0.49,p0.001,respectively).AScvO2thresholdvalueof4%allowedthedefinitionofRandNRpatientswith86%sensitivity(95%CI;57–98%)and81