ARDS肺复张的实施

ARDS肺复张的实施科学与艺术的困惑内容提要•肺保护性通气策略不能解决解决的问题•肺泡塌陷的病理生理后果•肺复张的临床实施–Proneposition–Spontaneousbreathing–HighVTandsigh–RMARDSnet:小潮气量通气LowTidalVolumesTraditionalTidalVolumesP-valueDeathbeforedischargehomeandbreathingwithoutassistant(%)31.039.80.007Breathingwithoutassistancebydays(%)65.755.00.001NOofventilatorfreedaysDay1-2812±1110±110.007Boratrauma,Day1-28(%)10110.43NOofdayswithoutfailureofnonpulmonaryorgansorsystemsDay1-2815±1112±110.006ARDSNet.NEnglJMed.2000May4;342(18):1301-8.Lowtidalvolume:morealvcollapse小Vt不能复张塌陷肺泡，加重低氧血症实施肺保护性通气策略至少15~25%患者需提高FiO2邱海波,刘大为,陈德昌等.中华麻醉学杂志,1998,18:202-205CollapsedairwayV1V2PressureVolumeV1V1+V2OpeningpressureNormalARDSPEEPadjustmentLIP：塌陷肺泡开始复张的压力不是全部塌陷肺泡复张的压力PEEPnotenough:morealvkeepcollapse30kgPigPostLavagePCVPaw13cmH2OPEEP5cmH2OExperimentalstudy-PigwithARDS许红阳，邱海波.ARDS绵羊肺复张容积测定方法的比较.中国危重病急救医学，2004,16:413.邱海波.PEEP对ARDS肺复张容积及氧合影响的临床研究.中国危重病急救医学，2004,16:399.ClinicalTrial－11ARDSpats0100200300400复张容积(ml)-PaO2/FiO2051015PEEP(cmH2O)肺复张容积PaO2/FiO2A.HypoxamiaB.ShearforcesC.SurfactantsinactivateD.BiotraumaandMODSPathophysiologyConsolidationandalvcollapseA.低氧血症肺泡塌陷：ARDS重力依赖区炎症或不张区生理性低氧缩血管反应：障碍HowDoesExcessiveMechanicalStressInflametheLung?“Shear”Verbruggeetal.CritCareMed1999;27：779Ventilator-associatedlunginjury012345Control7/045/1045/0PurineProtein•Purine:amarkerofATPbreakdownandVILI•42SDrats•PCV6min•PCVPre/PEEP•BALFpurineandproteinLachmann.ICM,1994;20:6-11Intra-alveolarproteinsinactivatealvsurfactantinadose-dependentway1mgsurfactant=inhibitoryeffectof1mgplasmaproteinC.Surfactant灭活Surfactantmoveaway•Whenlungregionscollapseatend–expiration,surfactantmoleculesmoveawayfromthealvsurfacetowardterminalbronchioles•and•cannotbereusedduringnextinflationRoubyJJ.AmJRespirCritCareMed,2001,165:1182D.预防Biotrauma和MODSMariniJJ,GattinoniL.Ventilatorymanagementofacuterespiratorydistresssyndrome:aconsensusoftwoCritCareMed.2004Jan;32(1):250-5.“Stretch”“Shear”AirwayTrauma俯卧位通气的病理生理特征•改善通气过程–胸膜腔压力梯度–顺应性胸壁–促进分泌物的清除ClosingpressureClosingpressure11.10%66.70%100%85.70%0.00%25.00%50.00%75.00%100.00%PPV0.5hPPV2h百分率ARDSp组ARDSexp组TimecourseofProneonPaO2/FiO2betweenARDSpvsARDSexpTimeresponseofPronepositiononPaO2/FiO2betweenARDSpvsARDSexp黄英姿,邱海波.肺内外源性ARDS实施俯卧位通气时间的选择.中华内科杂志2004,43(12):883-887保留自主呼吸的优点Paw[cmH2O]%OpeningandClosingPressures0510152025303540455001020304050OpeningpressureClosingpressure5patients,ALI/ARDSFromCrottietalAJRCCM2001.Someunitscan’tbekeptopenbyanyreasonablePEEP!Amato:CT+PVCurveHeartSpPVLIPUIPInsprecruitLargerVt/Sigh:PressuremustbehighenoughEvenuptoUIP许红阳，邱海波.ARDS绵羊肺复张容积测定方法的比较.中国危重病急救医学，2004,16:413.邱海波.PEEP对ARDS肺复张容积及氧合影响的临床研究.中国危重病急救医学，2004,16:399.ClinicalTrial－11ARDSpats0100200300400复张容积(ml)-PaO2/FiO20PEEP5VT6PEEP5VT10PEEP15VT6PEEP(cmH2O)肺复张容积PaO2/FiO2RecruitmentisTime-Dependent~40SECONDSRecruitmentmannuvers•BasicPrinciples•MethodsforRecruitment•ExperimentalStudiesandClinicalTrials–Efficacy–Hazards1.控制性肺膨胀(SI)法2.PEEP递增法3.压力控制(PCV)法MethodsforRecruitment1.CPAP模式:PS0,PEEP30-40cmH2O,20-50s2.BIPAP:Ph/PL30-40cmH2O,20-50s3.InspHold:将吸气保持键按住，持续20-40s控制性肺膨胀(SI)法MultipleManeuversMayBeNeededForOptimumRMEffectFujinoetal,CritCareMed2001;29(8):1579-1586Post-RMPEEPDeterminesPaO2AverageddatafromthreemodelsRMS-CLim,CCM2004TransientBenefitPost-RM-PEEP－肺开放效应持续时间的决定因素CCM,2004,32:2371-237728mixed-breedpigsModelsofARDS:OAVILIPneumonia(PNM)RMSIIncreasedPEEPPCV肺开放后的PEEP选择----PaO2/FiO21.RM后PEEP:20cmH2O2.PEEP递减:2cmH2O/5min3.PEEP阈值:PaO2/FiO2400的PEEP或PaO2/FiO2降低5%4.PEEP:PEEP阈值+2cmH2OBASELINEVENTILATIONTidalvolume=6ml/kgPEEP=5cmH2OModifyPEEPtogeta1.1ｂ0.9recruitingmaneuverMeasureｂ1.1ｂ0.9LeavePEEPunchangedｂ0.9IncreasePEEPuntil1.1stressindex0.9ｂ1.1DecreasePEEPuntil1.1stressindex0.9CritCareMed,2004,32:1018-1027肺开放后的PEEP选择----StressindexImplications•RM的有效性–ALI的病因(directvsindirect)–PostRMPEEP–Methodincertainsettings•RMhazardsaregreatestandeffectivenessleastinpneumonia-causedacutelunginjury•PCVmaybebettertoleratedthanSIRecommendations•UsePCVinpreferencetoSI–Safer,“multiple”,effective,maintainsventilation,simple•Monitorhemodynamicsduringrecruitinginterval.•以下情况需重复作RM:体位改变,管路断开,呼吸力学特征或PaO2明显恶化•对于顽固性难治性ARDS患者,可考虑反复RM和更高的压力•EmployPronePositionand/orPEEPtoconsolidateRMbenefit.