【完整版】急性呼吸窘迫综合征-英文课件文档

ACUTERESPIRATORYDISTRESSSYNDROMEMichaelL.Fiore,MD–FellowinCriticalCareMedicine MaryW.Lieh-Lai,MD,Director,ICUandFellowshipProgramDivisionofCriticalCareMedicineChildren’sHospitalofMichigan/WayneStateUniversityA.K.A.

AdultRespiratoryDistressSyndromeDaNangLungTransfusionLungPostPerfusionLungShockLungTraumaticWetLungHISTORICALPERSPECTIVESDescribedbyWilliamOslerinthe1800’sAshbaugh,BigelowandPetty,Lancet–196712patientspathologysimilartohyalinemembranediseaseinneonatesARDSisalsoobservedinchildrenNewcriteriaanddefinitionORIGINALDEFINITIONAcuterespiratorydistressCyanosisrefractorytooxygentherapyDecreasedlungcomplianceDiffuseinfiltratesonchestradiographDifficulties:lacksspecificcriteriacontroversyoverincidenceandmortalityREVISIONOFDEFINITIONS1988:four-pointlunginjuryscoreLevelofPEEPPaO2/FiO2ratioStaticlungcomplianceDegreeofchestinfiltrates1994:consensusconferencesimplifiedthedefinition1994CONSENSUSAcuteonsetmayfollowcatastrophiceventBilateralinfiltratesonchestradiographPAWP<18mmHgTwocategories:AcuteLungInjury-PaO2/FiO2ratio<300ARDS-PaO2/FiO2ratio<200EPIDEMIOLOGYEarliernumbersinadequate(vaguedefinition)Using1994criteria:17.9/100,000foracutelunginjury13.5/100,000forARDSCurrentepidemiologicstudyunderwayInchildren:approximately1%ofallPICUadmissionsINCITINGFACTORSShockAspirationofgastriccontentsTraumaInfectionsInhalationoftoxicgasesandfumesDrugsandpoisonsMiscellaneousSTAGESAcute,exudativephaserapidonsetofrespiratoryfailureaftertriggerdiffusealveolardamagewithinflammatorycellinfiltrationhyalinemembraneformationcapillaryinjuryprotein-richedemafluidinalveolidisruptionofalveolarepitheliumSTAGESSubacute,Proliferativephase:persistenthypoxemiadevelopmentofhypercarbiafibrosingalveolitisfurtherdecreaseinpulmonarycompliancepulmonaryhypertension

STAGESChronicphaseobliterationofalveolarandbronchiolarspacesandpulmonarycapillariesRecoveryphasegradualresolutionofhypoxemiaimprovedlungcomplianceresolutionofradiographicabnormalitiesMORTALITY40-60%Deathsdueto:multi-organfailuresepsisMortalitymaybedecreasinginrecentyearsbetterventilatorystrategiesearlierdiagnosisandtreatmentPATHOGENESISIncitingeventInflammatorymediatorsDamagetomicrovascularendotheliumDamagetoalveolarepitheliumIncreasedalveolarpermeabilityresultsinalveolaredemafluidaccumulationNORMALALVEOLUSTypeIcellEndothelialCellRBC’sCapillaryAlveolarmacrophageTypeIIcellACUTEPHASEOFARDSTypeIcellEndothelialCellRBC’sCapillaryAlveolarmacrophageTypeIIcellNeutrophilsPATHOGENESISTargetorganinjuryfromhost’sinflammatoryresponseanduncontrolledliberationofinflammatorymediatorsLocalizedmanifestationofSIRSNeutrophilsandmacrophagesplaymajorrolesComplementactivationCytokines:TNF-a,IL-1b,IL-6PlateletactivationfactorEicosanoids:prostacyclin,leukotrienes,thromboxaneFreeradicalsNitricoxidePATHOPHYSIOLOGYAbnormalitiesofgasexchangeOxygendeliveryandconsumptionCardiopulmonaryinteractionsMultipleorganinvolvementABNORMALITIESOFGASEXCHANGEHypoxemia:HALLMARKofARDSIncreasedcapillarypermeabilityInterstitialandalveolarexudateSurfactantdamageDecreasedFRCDiffusiondefectandrighttoleftshuntOXYGENEXTRACTIONVO2=QxHbX13.4X(SaO2-SvO2)ArterialInflow(Q)capillaryO2O2O2O2O2O2O2VenousOutflow(Q)CellO2(AdaptedfromtheICUBookbyP.Marino)OXYGENDELIVERYDO2=QXCaO2DO2=QX(1.34XHbXSaO2)X10Q=cardiacoutputCaO2=arterialoxygencontentNormalDO2:520-570ml/min/m2Oxygenextractionratio=(SaO2-SvO2/SaO2)X100NormalO2ER=20-30%HEMODYNAMICSUPPORTMaxO2extractionCriticalDO2VO2=DO2XO2ERDO2VO2NormalMaxO2extractionCriticalDO2AbnormalFlowDependencyDO2VO2SepticShock/ARDSOXYGENDELIVERY&CONSUMPTIONPathologicflowdependencyUncouplingofoxidativedependencyOxygenutilizationbynon-ATPproducingoxidasesystemsIncreaseddiffusiondistanceforO2betweencapillaryandalveolusCARDIOPULMONARYINTERACTIONSA=PulmonaryhypertensionresultinginincreasedRVafterloadB=ApplicationofhighPEEPresultingindecreasedpreloadA+B=DecreasedcardiacoutputRESPIRATORYSUPPORTConventionalmechanicalventilationNewermodalities:HighfrequencyventilationECMOInnovativestrategiesNitricoxideLiquidventilationExogenoussurfactantMANAGEMENTMonitoring:RespiratoryHemodynamicMetabolicInfectionsFluids/electrolytesMANAGEMENTOptimizeVO2/DO2relationshipDO2hemoglobinmechanicalventilationoxygen/PEEPVO2preloadafterloadcontractilityCONVENTIONALVENTILATIONOxygenPEEPInverseI:EratioLowertidalvolumeVentilationinpronepositionRESPIRATORYSUPPORTGoal:maintainsufficientoxygenationandventilation,minimizecomplicationsofventilatorymanagementImproveoxygenation:PEEP,MAP,Ti,O2Improveventilation:changeinpressureMechanicalVentilationGuidelinesAmericanCollegeofChestPhysicians’ConsensusConference1993GuidelinesforMechanicalVentilationinARDSWhenpossible,plateaupressures<35cmH2OTidalvolumeshouldbedecreasedifnecessarytoachievethis,permittingincreasedpCO2PEEP-BenefitsIncreasestranspulmonarydistendingpressureDisplacesedemafluidintointerstitiumDecreasesatelectasisDecreaseinrighttoleftshuntImprovedcomplianceImprovedoxygenationNoBenefittoEarlyApplicationofPEEPPepePEetal.NEJM1984;311:281-6.ProspectiverandomizationofintubatedpatientsatriskforARDSVentilatedwithnoPEEPvs.PEEP8+for72hoursNodifferencesindevelopmentofARDS,complications,durationofventilation,timeinhospital,durationofICUstay,morbidityormortalityEverythinghingesonthematterofevidence

CarlSaganPressure-controlledVentilation(PCV)Time-cycledmodeApproximatesquarewavesofapresetpressureareappliedandreleasedbymeansofadeceleratingflowMorelaminarflowattheendofinspirationMoreevendistributionofventilationinpatientswithmarkeddifferentresistancevaluesfromoneregionofthelungtoanotherPressure-controlledInverse-ratioVentilationConventionalinspiratory-expiratoryratioisreversed(I:E2:1to3:1)LongertimeconstantBreathstartsbeforeexpiratoryflowfrompriorbreathreachesbaselineauto-PEEPwithrecruitmentofalveoliLowerinflatingpressuresPotentialfordecreaseincardiacoutputduetoincreaseinMAPExtracorporealMembraneOxygenation(ECMO)ZapolWMetal.JAMA1979;242(20):2193-6Prospectivelyrandomized90adultpatientsMulticentertrialConventionalmechanicalventilationvs.mechanicalventilationsupplementedwithpartialvenoarterialbypassNobenefitPartialLiquidVentilation(PLV)VentilatingthelungwithconventionalventilationafterfillingwithperfluorocarbonPerflubron20timesO2and3timestheCO2solubilityHeavierthanwaterHigherspreadingcoefficientStudiesinanimalmodelssuggestimprovedcomplianceandgasexchangePartialLiquidVentilation(PLV)CLLeach,etal.NEJM1996;335:761-7.TheLiquiVentStudyGroup13prematureinfantswithsevereRDSrefractorytoconventionaltreatmentNoadverseeventsIncreasedoxygenationandimprovedpulmonarycompliance8of10survivorsPartialLiquidVentilation(PLV)HirschletalJAMA1996;275:383-38910adultpatientsonECMOwithARDSAnnSurg1998;228(5):692-7009adultpatientswithARDSonconventionalmechanicalventilationImprovementsingasexchangewithfewcomplicationsNorandomizedorcasecontrolledtrialsHigh-FrequencyJetVentilationCarlonGCetal.Chest1983;84:551-59Prospectiverandomizationof309adultpatientswithARDStoreceiveHFJVvs.VolumeCycledVentilationVCVprovidedahigherPaO2HFJVhadslightlyimprovedalveolarventilationNodifferenceinsurvival,ICUstay,orcomplicationsHighFrequencyOscillatingVentilator(HFOV)RaiseMAPRecruitlungvolumeSmallchangesintidalvolumeImpedesvenousreturnnecessitatingintravascularvolumeexpansionand/orpressorsPredictingoutcomeinchildrenwithsevereacuterespiratoryfailuretreatedwithhigh-frequencyventilationSarnaikAP,MeertKL,PappasMD,SimpsonPM,Lieh-LaiMW,HeidemannSMCritCareMed1996;24:1396-1402SUMMARYOFRESULTSSignificantimprovementinpH,PaCO2,PaO2andPaO2/FiO2occurredwithin6hoursafterinstitutionofHFVTheimprovementingasexchangewassustainedSurvivorsshowedadecreaseinOIandincreaseinPaO2/FiO2twentyfourhoursafterinstitutingHFVwhilenon-survivorsdidnotPre-HFVOI>20andfailuretodecreaseOIby>20%atsixhourspredicteddeathwith88%(7/8)sensitivityand83%(19/23)specificity,withanoddsratioof33(p=.0036,95%confidenceinterval3-365)STUDYCONCLUSIONSInpatientswithpotentiallyreversibleunderlyingdiseasesresultinginsevereacuterespiratoryfailurethatisunresponsivetoconventionalventilation,highfrequencyventilationimprovesgasexchangeinarapidandsustainedfashion.Themagnitudeofimpairedoxygenationanditsimprovementafterhighfrequencyventilationcanpredictoutcomewithin6hours.HighFrequencyOscillatingVentilation(HFOV)–PediatricARDSArnoldJHetal.CritCareMed1994;22:1530-1539.Prospective,randomizedclinicalstudywithcrossoverof70patientsHFOVhadfewerpatientsrequiringO2at30daysHFOVpatientshadincreasesurvivorSurvivorshadlesschroniclungdiseaseNewEnglandJournalofMedicine2000;342:1301-8STUDYCONCLUSIONInpatientswithacutelunginjuryandtheacuterespiratorydistresssyndrome,mechanicalventilationwithalowertidalvolumethanistraditionallyusedresultsindecreasedmortalityandincreasesthenumberofdayswithoutventilatoruseIncreasedoxygenationandimprovedpulmonarycomplianceNORMALALVEOLUSPartialLiquidVentilation(PLV)SelectivelyimprovesperfusionofventilatedareasTargetorganinjuryfromhost’sinflammatoryresponseanduncontrolledliberationofinflammatorymediators1994:consensusconferencesimplifiedthedefinitionStaticlungcomplianceUncouplingofoxidativedependencyA+B=Decreasedcardiacoutput10adultpatientsonECMOwithARDSAmericanCollegeofChestPhysicians’ConsensusConference1993Multicenterstudyof725patientswithsepsisinducedARDSHISTORICALPERSPECTIVESIncreasedoxygenationandimprovedpulmonarycomplianceAcuteonsetJAMA1979;242(20):2193-6PATHOGENESISPronePositionImprovedgasexchangeMoreuniformalveolarventilationRecruitmentofatelectasisindorsalregionsImprovedposturaldrainageRedistributionofperfusionawayfromedematous,dependentregionsStaticlungcompliancepathologysimilartohyalinemembranediseaseinneonatesEndothelial4X(SaO2-SvO2)RecoveryphaseGuidelinesforMechanicalVentilationinARDSInpatientswithacutelunginjuryandtheacuterespiratorydistresssyndrome,mechanicalventilationwithalowertidalvolumethanistraditionallyusedresultsindecreasedmortalityandincreasesthenumberofdayswithoutventilatoruseSurvivorsshowedadecreaseinOIandincreaseinPaO2/FiO2twentyfourhoursafterinstitutingHFVwhilenon-survivorsdidnotMulticenterstudyof725patientswithsepsisinducedARDS1988:four-pointlunginjuryscoreImpedesvenousreturnnecessitatingintravascularvolumeexpansionand/orpressorsPronePositionEndothelialImproveventilation:changeinpressureMoreevendistributionofventilationinpatientswithmarkeddifferentresistancevaluesfromoneregionofthelungtoanotherOxygendeliveryandconsumptionPronePositionNakosGetal.AmJRespirCritCareMed2000;161:360-68Observationalstudyof39patientswithARDSindifferentstagesImprovedoxygenationinprone(PaO2/FiO2189±34pronevs.83±14supine)after6hoursNoimprovementinpatientswithlateARDSorpulmonaryfibrosisPronePositionNEJM2001;345:568-73Prone-SupineStudyGroupMulticenterrandomizedclinicaltrial304adultpatientsprospectivelyrandomizedto10daysofsupinevs.proneventilation6hours/dayImprovedoxygenationinpronepositionNoimprovementinsurvivalExogenousSurfactantSuccesswithinfantswithneonatalRDSExosurfARDSSepsisStudy.Anzuetoetal.

NEJM1996;334:1417-21RandomizedcontroltrialMulticenterstudyof725patientswithsepsisinducedARDSNosignificantdifferenceinoxygenation,durationofmechanicalventilation,hospitalstay,orsurvivalExogenousSurfactantAerosoldeliverysystem–only4.5%ofradiolabeledsurfactantreachedlungsOnlyreacheswellventilated,lesssevereareasNewapproachestodeliveryareunderstudy,includingtrachealinstillationandbronchoalveolarlavageInhaledNitricOxide(iNO)PulmonaryvasodilatorSelectivelyimprovesperfusionofventilatedareasReducesintrapulmo