ABG 简明血气分析.ppt

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1、ABGINTERPRETATION血气分析解读SIMCICULiuObjectivesWhat’sanABG?UnderstandingAcid/BaseRelationshipGeneralapproachtoABGInterpretationClinicalcausesAbnormalABG’sCasestudiesWhatisanABGArterialBloodGas动脉血气Drawnfromartery-radial,brachial,femoral由动脉取样——一般取桡动脉、肱动脉、股动脉Itisa

2、ninvasiveprocedure.这是侵入性检查Cautionmustbetakenwithpatientonanticoagulants.有凝血功能障碍的患者慎用Helpsdifferentiateoxygendeficienciesfromprimaryventilatorydeficienciesfromprimarymetabolicacid-baseabnormalities协助区分缺氧/通气不足和酸碱代谢异常WhatIsAnABG?pH[H+]PCO2PartialpressureCO2PO2

3、PartialpressureO2HCO3BicarbonateBEBaseexcessSaO2OxygenSaturationAcid/BaseRelationshipThisrelationshipiscriticalforhomeostasis酸碱平衡对内环境是非常重要的SignificantdeviationsfromnormalpHrangesarepoorlytoleratedandmaybelifethreatening酸碱严重失衡后果严重，甚至可能致命AchievedbyRespirator

4、yandRenalsystems一般由呼吸系统和肾脏决定CaseStudyNo.160y/omalecomesERc/oSOB.Tachypneic,tachycardic,diaphoreticandCyanotic.Dxacuteresp.failureandABG’sShowPaCO2wellbelownl,pHabovenl,PaO2isverylow.ThebloodgasdocumentResp.failureduetoprimaryO2problem.60岁男性进入急诊室。查体见呼吸过速、心动过

5、速、大汗、发绀，诊断急性呼衰。动脉血气分析结果PaCO轻度降低，PH升高，PaO2非常低。结果显示其主要问题为缺氧CaseStudyNo.260y/omalecomesERc/oSOB.Tachypneic,tachycardic,diaphoreticandCyanotic.Dxacuteresp.failureandABG’sShowPaCO2veryhigh,lowpHandPaO2ismoderatelylow.ThebloodgasdocumentResp.failureduetoprimari

6、lyventilatorinsufficiency.60岁男性进入急诊室。查体，呼吸过塑，心动过速，大汗，发绀，诊断急性呼衰。动脉血气分析结果显示PaCO2非常高，PH降低，PaO2中度降低。结果显示其主要问题为通气不足。BuffersTherearetwobuffersthatworkinpairsH2CO3NaHCO3CarbonicacidbasebicarbonateThesebuffersarelinkedtotherespiratoryandrenalcompensatorysystem两者和呼

7、吸、肾脏代偿密切相关RespiratoryComponentfunctionofthelungsCarbonicacidH2CO3Approximately98%normalmetabolitesareintheformofCO2CO2+H2OH2CO3excessCO2exhaledbythelungsMetabolicComponentFunctionofthekidneysbasebicarbonateNaHCO3ProcessofkidneysexcretingH+intotheurineandre

8、absorbingHCO3-intothebloodfromtherenaltubules肾脏将H+排泄至尿液，并从肾小管重吸收HCO3-1)activeexchangeNa+forH+betweenthetubularcellsandglomerularfiltrate在肾小管和肾小球主动用Na+交换H+2)carbonicanhydraseisanenzymethataccelerates