肺内分流zuihou.ppt

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1、Giveamanafishandyoufeedhimforaday.Teachamantofishandyoufeedhimforalifetime.111122223333444456肘静脉、下肢、上腔、右心房、右心室、肺动脉的静脉氧分压？静脉采血点的氧分压血压Hypoxiaoccursmoreeasilythanhypercarbia.Why?PaO2的降低远多于PaCO2的升高出着容易进着难浓度差、物理弥散化学解离性质，气体分压Pt=+++P1P2P3P4气体分压PO2+PCO2=aconstantInthealveolus,themixtureofgassescontainsni

2、trogen,watervapor,tracegasses,oxygenandcarbondioxide.Attheendofabreath,thepressureinthealveolus=atmosphericpressure.So..PB=PN2+PH2O+Ptracegasses+PO2+PCO2Or..PO2+PCO2=aconstant一个多了另一个就少了Theburlyalveolus(highV/Q).Theweaklingalveolus(lowV/Q).Afundamentalquestion:IntermsofarterialO2andCO2tensions,cant

3、heburlyalveoluscompensatefortheweaklingalveolus?forPaO2.YesorNo？forPaCO2.YesorNo？Thisbasicfactexplainsalot.Knowitcold.Theweaklingalveolus(shuntorV/Qmismatch)TheburlyalveolusCantheburlyalveoluscompensatefortheweaklingalveolus?Notforoxygen!Theburlyalveoluscan’tsaturatehemoglobinmorethan100%.SaO2ofeq

4、ualadmixtureofburlyandweaklingalveolarblood=89%pO2=50mmHgSaO2=75%pO2=50mmHgSaO2=80%SaO2=75%SaO2=98%pO2=130mmHgpO2=40mmHgpO2=130mmHgpO2=40mmHg肌体的储备和动员TheweaklingalveolusTheburlyalveolusCantheburlyalveoluscompensatefortheweaklingalveolus?Yes,forCO2!Theburlyalveolus,ifittriesrealhard,canblowoffextraC

5、O2.PulmonaryvenousbloodpCO2andPaCO2=40mmHgpCO2=44mmHgpCO2=44mmHgpCO2=36mmHgpCO2=46mmHgpCO2=36mmHgpCO2=46mmHg健壮的肺能排出更多的二氧化碳而吸进和运载储备更多的氧Shunt,or“weakling”(lowV/Q)alveolusSaO2=75%“Burly”(highV/Q)alveolusSaO2=99%NormalalveolusSaO2=96%Equaladmixtureof“weakling”and“burly”alveolarbloodhasSaO2=(75+99)/2=8

6、7%.AveragealveolarPACO2=40mmHg.Hence,PaCO2=40mmHgForCO2,burlyalveolusCANcompensatefortheweaklingalveolus.WeaklingalveolusBurlyalveolusNormalalveolusAdmixtureofburlyandweaklingalveolarblood二氧化碳的事好解决氧的事不好办面积时间溶解缓冲难受都有余地，有通气量就行。PaO2isalwaysslightlylowerthanPAO2？问题什么是肺内分流、肺外分流？正常肺内分流多少？分流的形式有哪些？分流增加的结

7、果？分流量如何判断评估测算？怎么减少分流？1.Gasexchange,2.Akeytolungdisorders,3.Unevendistributionoftidalvolumeandperfusion,4.Bloodgases,5.ThePO2-PCO2diagram,6.TheVA/Q-curve,7.Blood-R-curves,8.Deadspace,9.Anatomicvenous-to-arteria