Respiratory-Failure-呼吸衰竭VIP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,severeCOPD.DiffuseabilityDiffusionabnormalitymainlyinfluenceoxygenexchange.2.PulmonaryhypoventilationItmaycausehypercapnic-hypoxicrespiratoryfailure.Pulmonaryhypoventilationincludesrestrictivehypoventilationandobstructivehypoventilation.Somediseasesinfluencedcentralnervoussystem,peripheralnervoussystem,chestwallrespiratorymusclesandpulmonarycompliancemayallcauserestrictivehypoventilation.SomecommonconditionsthatmaycauseventilatoryfailurewithhypercapneaTheseconditionsincludebrainstemlesion,alteredneuromusculartransmission(guillain-barresyndrome),muscleweakness(malnutrition,shock,hypoxemia,hypokalemia),increasedairwayresistance(upperairwayobstruction,increasedbronchialsecretionsandedema),decreasedlungcompliance(infection,atelectasis,interstitialfibrosis,acutelunginjury),decreasedchestwallcompliance(chestwalltrauma,pleuraleffusion,pneumothorax).COPDandasthmaarethemostcommondiseaseassociatedtoobstructivehypoventilation.Inourclinicalwork,multifactorsinvolveinthecourseofrespiratoryfailure.Forexample,aCOPDpatientwithseverepulmonaryinfection,hispulmonarygasexchangeabilityandpulmonaryventilationareallabnormal.PathophysiologyHypoxiaandhypercapnicmayinfluencefunctionsofmanyimportantorgansandsystems,includingrespiratorysystem,cardiovascularsystem,centralnervesystem,bloodsystemanddigestivesystemandrenalfunctio...