RespiratoryFailure第一页,共四十九页。1.AbstractsRespiratoryfailure,whetheracuteorchronic,isafrequentlyfacedproblemandamajorcauseofdeathinourcountry.Forexample,mortalityfromCOPD,whichendsindeathfromrespiratoryfailure,continuestoincrease.Morethan70%ofthedeathsinpatientswithpneumoniaareattributedtorespiratoryfailure.第二页,共四十九页。2.DefinitionRespiratoryfailureisfunctionalacuteorchronicdisordercausedbyanyconditionthataffectsthelung’sabilitytomaintainarterialoxygenationorcarbondioxide(CO2)elimination.Itisdefinedasaconditioninwhichthisgasexchangedeterioratesbelowtheusuallevel,sothatarterialoxygentensiondecreases,withorwithoutanabnormalriseinarterialcarbondioxidetension.第三页,共四十九页。3.ClassificationsGenerallybothacuteandchronicrespiratoryfailuremaybedividedintotwomaincategories:第四页,共四十九页。TyperespiratoryfailureⅠTyperespiratoryfailureisalsocalledⅠhypoxicrespiratoryfailure,whichmeansthatseverelyreducesarterialoxygentension(PaO2<60mmHg),CO2retentionisnotexist.Thistypeofrespiratoryfailureiscausedbyafailureofgasexchange.第五页,共四十九页。TyperespiratoryfailureⅡTyperespiratoryfailureisalsomeantthatⅡhypercapnic-hypoxicrespiratoryfailure.Arterialbloodgasvaluesshowsthatarterialcarbondioxidetensionismorethan50mmHgandarterialoxygentensionislessthan60mmHgTyperespiratoryismainlycausedbyⅡhypoventilation.第六页,共四十九页。PathogenesisMainlydiscusschronicrespiratoryfailurewehaveknownthatthelungs’abilityisgasexchange.Thegasexchangeinvolvesnotonlyoxygenationbutalsocarbondioxideelimination.第七页,共四十九页。PathogenesisRespiratoryfailureismainlyassociatedwithpulmonarygasexchangeandpulmonaryventilation.第八页,共四十九页。1.pulmonarygasexchangeismainlydeterminedbyventilation-perfusion(V/Q)ratiosanddiffuseabilityV/Qmismatch:AneffectivelunggasexchangeneedsnotonlysufficientlungventilationandlungbloodvolumesbutalsoanadequateV/Qratios.Usually,thevolumeofventilationis4liters/min.Thevolumeoflungbloodis5liters/min.Sotheratiosis0.8第九...