新生儿呼吸窘迫综合征NRDS英文

新生儿呼吸窘迫综合征NRDS英文第1页/共23页NeonatalRespiratoryDistressSyndrome(NRDS)

or:HyalineMembraneDisease(HMD)MostcommoncauseofrespiratoryfailureinthefirstdaysOccurringin1~2%ofnewborninfants(GA26~28w,50%,30~31w,lessthan20~25%)Mortality~50%at20yrsago,Survive80~90%nowHighrisk:IDM,GA<37w,multipreg.,C-section,asphyxia,coldstress,historyofprioraffected,maleorwhiteinfantsLowrisk:chronicorpregnancy-associatedhypertension,maternalopiateaddiction,PROM,antenatalcorticosteroid第2页/共23页LungDevelopment

EmbryonicLungDevelopmentFetalLungDevelopment

(Pseudoglandular,Canalicular,TerminalSaccular)

PostnatalLungDevelopment第3页/共23页EmbryonicLungDevelopment

primitivelungmainbronchilobarbronchisegmentalbronchi第4页/共23页FetalLungDevelopmentPseudoglandularStage~7th–16thweekPrimitivebronchialtreeTerminalbronchioles第5页/共23页

FetalLungDevelopmentCanalicularStage~16th–24thweekTerminalSaccularStage~24th–36thweekRespiratorybronchiolesTransitorysacculesandducts第6页/共23页PostnatalLungDevelopmentPostnatalDevelopment~birth

–8yearAlveolarperiodSecondaryalveolarseptaAlveolarductsandalveoli第7页/共23页Surfactantstartsynthesisin20~24wincreasein28~32wmeetdemandsafter35wdoubleinalveolarwithin24hadultlevelafter3~7dhalf-life12~24hrenewin24~48,>90%reuse第8页/共23页SurfactantCompositionPhospholipid90%(neutral5%) saturated 50％ unsaturated 35％Protein 10％ (albumin5%) SP-A,30~35kDa,18ologomer,hydrophilicD,43kDa,12oligomer SP-B,8kDa,dimer,hydrophobicC,4kDa,dimer第9页/共23页FunctionofPulmonarySurfactantDecreasealveolarsurfacetension,reducerespiratoryworkMaintainalveoliinflationandfunctionalresidualcapacityAcceleratelungfluidabsorption,reducealveolareffusionPathogenOpsonization,alveolarmacrophageactivation

Effects:improveoxygenation,ameliorateventilation/perfusionanti-inflammationFluidsurfacetension

Pressure(P)=2xsurfacetension()radius(r)第10页/共23页EtiologyandPathophysilogySurfactantlowersthesurfacetensionofalveolarmembranePulmonaryimmaturityresultsinsurfactantdeficiencyAlveolicollapseattheendofexpirationleadstorespiratoryfailureSurfactantdeficiencycanariseafterasphyxia/shockandacidosis第11页/共23页Pathologyatelectasis,pulmonaryedema,vascularcongestion,hemorrhage,generalizedcapillaryleakandmucosalnecrosisleadstothesmallairfilledterminalairways,therespiratorybronchiolesandalveolarducts,beingsurroundedbycollapsedalveolifilledwithdebrisinanearuniformdistribution(hyalinemembranes)第12页/共23页PathophysiologyLackofalveolarsurfactantinthelungsofinfants

AveryandMead,AmJDisChild1959

progressiveatelectasislossoffunctionalresidualcapacity(FRC)alterationofventilation-perfusionratioWeakrespiratorymusclesandcompliantchestwallimpairalveolarventilation

Diminishedoxygenation,cyanosisandacidosisincreasedpulmonaryvascularresistance(PVR)right-to-leftshuntingthroughductusarterioususintrapulmanaryventilation-perfusionmismatch第13页/共23页ClinicalPresentationPresentatbirthorwithinseveralhoursafterbirth:tachypneagruntingretractionscyanosiswithincreasingoxygenrequirementsPhysicalfindings:ralespoorairexchangeuseofaccessorymusclesofbreathingnasalflaringabnormalpatternsofrespirationwithapnea第14页/共23页RadiographicChangesofRDSabellshapedthoraxwithdiffuseandsymmetrical“groundglass”infiltrates,airbronchogramsanddecreasedlungvolumeorseverebilateralopacitycharacterizedbythetermof“whiteout”

第15页/共23页LaboratoryFindingsRespiratoryandmetabolicacidosis

Phospholipid(PL)/Sphingomyelin(S)<2:1;orPhosphatidylglycerol(PG)negativeShakingTest

Add1mLof95%alcoholto1mLofgastricfluid,shakefor15seconds,watchforfoamformation第16页/共23页DiagnosisandDifferentialDiagnosis“Wetlung”ortransientrespiratorydistress

AmnioticfluidormeconiumaspirationsyndromeGroupBhemolyticStreptococcuspneumoniaDiaphragmatichernia第17页/共23页TreatmentCarefulassessmentandresuscitationAdequateventilation,oxygenation,circulationandtemperaturemustbeassuredSurfactantreplacementtherapy(natural/synthetic)Ventilatorymanagement(CPAP,IPPV,PEEP)Acid-baseandelectrolytehomeostasisClosureofpatentductusarteriousus(PDA)SupportivetreatmentAntibiotic第18页/共23页RespiratoryManagementContinuousPositiveAirwayPressure(CPAP)

Indication:whenFiO2>0.6,PaO2<50mmHgorTcSO2<85%

Pressure:4~10cmH2O,flow5L/min,32°C,humidity100%ConventionalMechanicalVentilation(CMV)

Indication:PaO2<50mmHgorTcSO2<85%withCPAP(8cm);PCO2>70mmHg;orfrequentapnea

Complication:PAL(pulmonaryairleak)BPD(bronchopulmonarydysplasia;orCLD)RLF(retrolentalfibroplasia)VAP(ventilator-associatedpneumonia)第19页/共23页ApplicationofPulmonarySurfactantIntratrachealinstillation:50~200mg/kg,6~12hintervalNeonatalRespiratoryDi