Respiratory-Failure-呼吸衰竭.pptVIP免费

RespiratoryFailure1.AbstractsRespiratoryfailure,whetheracuteorchronic,isafrequentlyfacedproblemandamajorcauseofdeathinourcountry.Forexample,mortalityfromCOPD,whichendsindeathfromrespiratoryfailure,continuestoincrease.Morethan70%ofthedeathsinpatientswithpneumoniaareattributedtorespiratoryfailure.2.DefinitionRespiratoryfailureisfunctionalacuteorchronicdisordercausedbyanyconditionthataffectsthelung’sabilitytomaintainarterialoxygenationorcarbondioxide(CO2)elimination.Itisdefinedasaconditioninwhichthisgasexchangedeterioratesbelowtheusuallevel,sothatarterialoxygentensiondecreases,withorwithoutanabnormalriseinarterialcarbondioxidetension.3.ClassificationsGenerallybothacuteandchronicrespiratoryfailuremaybedividedintotwomaincategories:TyperespiratoryfailureⅠTyperespiratoryfailureisalsocalledⅠhypoxicrespiratoryfailure,whichmeansthatseverelyreducesarterialoxygentension(PaO2<60mmHg),CO2retentionisnotexist.Thistypeofrespiratoryfailureiscausedbyafailureofgasexchange.TyperespiratoryfailureⅡTyperespiratoryfailureisalsomeantthathⅡypercapnic-hypoxicrespiratoryfailure.Arterialbloodgasvaluesshowsthatarterialcarbondioxidetensionismorethan50mmHgandarterialoxygentensionislessthan60mmHgTyperespiratoryismainlycausedbyhypovⅡentilation.PathogenesisMainlydiscusschronicrespiratoryfailurewehaveknownthatthelungs’abilityisgasexchange.Thegasexchangeinvolvesnotonlyoxygenationbutalsocarbondioxideelimination.PathogenesisRespiratoryfailureismainlyassociatedwithpulmonarygasexchangeandpulmonaryventilation.1.pulmonarygasexchangeismainlydeterminedbyventilation-perfusion(V/Q)ratiosanddiffuseabilityV/Qmismatch:AneffectivelunggasexchangeneedsnotonlysufficientlungventilationandlungbloodvolumesbutalsoanadequateV/Qratios.Usually,thevolumeofventilationis4liters/min.Thevolumeoflungbloodis5liters/min.Sotheratiosis0.8Anyofthefactorsinfluencedtheratiosmaymainlycausehypoxemiarespiratoryfailure.Forexample,V/Q>0.8,includingemphysema,pulmonaryembolism.V/Q<0.8,includingatelectasis...