1第十四章肺功能不全Chapter14RespiratoryFailure22概述概述GeneraldescriptionGeneraldescription肺的正常功能及其评价指标;肺的正常功能及其评价指标;呼吸衰竭的概念;呼吸衰竭的概念;呼吸衰竭的分类。呼吸衰竭的分类。3一、肺的正常功能及其评价指标;Respiratoryfunction(Externalrespiration)Non-respiratoryfunctions概述Generaldescription4呼吸功能的评价指标1.肺容量;肺通气功能的评价指标5呼吸功能的评价指标肺弥散量(diffusingcapacity):指气体在分压差作用下,每分钟经肺泡膜弥散的容量。正常值为:188ml/min·kPa。反映肺换气效率。肺泡气-动脉血氧分压差(PA-aO2):指肺泡气氧分压与动脉血氧分压之差。PA-aO2=PAO2-PaO2反映肺泡膜氧交换状态。2.换气功能的评价指标63.肺通气、换气功能指标呼衰指数(respiratoryfailureindex,RFI):指动脉血氧分压与吸入气氧浓度之比值。反映外呼吸效率。呼吸功能的评价指标74.呼吸动力功能:呼吸的动力功能包括:气道阻力(Raw)肺顺应性(CL)呼吸肌力(Fm)等。最常用的测定指标是气道阻力(Raw)。呼吸功能的评价指标8Non-respiratoryfunctionsFiltrationDefenseandimmunefunctionClearanceoftheforeignbodyintheairwayImmunefunctionMetabolism9GenerallydiagnosedbyPaO2<60mmHg(atsealevel);WhenFiO2<20%,thenRFI≤300canbeusedastheindexofdiagnosis.二、概念Concept二、概念ConceptExternalrespiratorydysfunction→PaO2<60mmHg(atsealevel)WithorwithoutPaCO2>50mmHg呼吸衰竭(Respiratoryfailure)10呼吸功能不全(Respiratoryinsufficiency)外呼吸功能障碍而不能维持血气稳态但未达上述水平;或在静息状态时,血气值正常,仅在运动负荷时PaO2才明显下降或伴PaCO2增高者,称为呼吸功能不全。二、概念Concept二、概念Concept111.AccordingtowhetherPaCO2isnormalTypeⅠPaO2↓(<60mmHg);PaCO2(normal)TypeⅡPaO2↓(<60mmHg);PaCO2↑(>50mmHg)三、呼吸衰竭的分类Classifications三、呼吸衰竭的分类Classifications122.AccordingtoPathogenesisVentilationRF;ExchangingRF.3.AccordingtoPrimarySiteCentralRF;PeripheralRF.4.AccordingtoDurationAcuteRF;ChronicRF.三、呼吸衰竭的分类Classifications三、呼吸衰竭的分类Classifications1313§1§1病因和发病机制病因和发病机制EtiologyandPathogenesisEtiologyandPathogenesisPulmonaryventilationdisorderPulmonarygasexchangedysfunction14一、肺通气功能障碍Pulmonaryventilationdisorder-----hypoventilation限制性通气不足Restrictivehypoventilation阻塞性通气不足Obstructivehypoventilation15(一)限制性通气不足Restrictivehypoventilation指呼吸动力减弱或胸廓和肺的扩张性能降低(弹性阻力增大)使肺泡扩张受限引起的通气功能障碍。Duringinspiration,thedilationorinflationofalveoliarerestricted.Itiscausedbythediseasesthataffectthedistensibilityofthealveolar.16①Paralysisofrespiratorymuscles②DecreasedcomplianceofchestwallCausesofrestrictivehypoventilation③Decreasedcomplianceoflung④Hydrothoraxorpneumothorax17由于气道阻塞或狭窄,使气道阻力增加引起的通气障碍。Obstructivehypoventilationisproducedbyairwayconstrictionorobstruction.(二)阻塞性通气不足ObstructivehypoventilationCentralairwayobstructionPeripheralairwayobstructiontracheacrotch影响气道阻力的最主要因素是气道内径181.中央气道阻塞:CentralairwayobstructionExtrathoracicairwayobstructionIntrathoracicairwayobstructionExpirationExpiration*吸气性呼吸困难Inspiratorydyspnea*呼气性呼吸困难ExspiratorydyspneaInspirationIntra-airwaypressure
AtmosphericpressureInspirationIntra-airwaypressure>Intra-thoracicpressureIntra-airwaypressure