病理生理学-呼吸系统ppt课件.ppt

病理生理学系DepartmentofPathophysiology高远生呼吸全过程
Respiration3Symbols呼吸衰竭(RespiratoryFailure)呼衰的类型ClassificationofRespiratoryfailure一、呼衰的原因和发病机制
RespiratoryFailure:TheCauses
andtheMechanisms（一）肺通气功能障碍:
DisordersinPulmonary
Ventilation1. 限制性通气不足（Restrictive
Hypoventilation）：肺泡扩张受限 气道阻力(正常人平静呼吸)：
80%:直径>2mm气管
20%:直径<2mm气管

病因：气管痉挛`肿胀`纤维化`渗出物`异物`肿瘤`气道内外压力改变阻塞位于胸外，表现为吸气性呼吸困难(InspiratoryDyspnea)阻塞位于胸内，表现为呼气性呼吸困难(ExspiratoryDyspnea)用力呼气时等压点(isobaricpoint)移向小气道问题：
呼吸衰竭?
限制性通气不足的定义及其发生原因?
胸内、胸外气道阻塞在呼吸中的差异?（二）弥散障碍
DiffusionImpairment毛细血管内皮细胞1. 弥散面积减少(DecreaseintheSurfaceAreaoftheMembrane)2. 弥散膜厚度增加(IncreaseintheThicknessoftheMembrane)3. 弥散时间缩短(ShorteningintheDiffusionTime)SolubilityCoefficient
(vol/vol,760mmHg):
O2: 0.024
CO2: 0.57正常静息状态下：

每分钟肺泡
通气量（VA)：~4L

每分钟肺血
流量（Q):~5L

VA/Q:0.8VA血液氧和二氧化碳解离曲线
OxygenandCarbonDioxideDissociationCurvesO2transportedas:
O2:1.5%
Hb.O2:98.5% 2. 解剖分流增加(IncreaseinAnatomicShunt)Q血液氧和二氧化碳解离曲线
OxygenandCarbonDioxideDissociationCurves问题：
弥散障碍的发生机制?
功能性分流,静脉血掺杂?
解剖分流,真性分流?
死腔样通气?肺泡-毛细血管膜(alveolarcapillarymembrane)损伤引起的急性呼吸衰竭。

病因：感染（肺炎，败血症等），休克，严重创伤，吸入毒物或胃酸等。30ARDS发生机制(Pathogenesis)Apreviouslyhealthy23-year-oldmalesustainednumeroustraumaticcrush,burn,andsmokeinhalationinjuriesduringalandingaccidentinanairplane.HisinitialB.P.was80/50mmHg,andhewasimmediatelyinfusedwithsalineatthemaximalrate.IntheERhewasintubatedandhadnosignsofpneumothorax.Hisorthopedicinjuriesandburnsweretreated.Theventilatorwasplacedontheassist-controlmodewiththeinitialsettingsofinspiredO2concentrationat40%,respirationrateat12/min,andtidalvolumeat900ml.Arterialbloodgasmeasurementswere:pH=7.47,PCO2of33mmHg,andPO2of62mmHg.24hrs.afteradmission,thepatientbecomesagitatedandhisrespirationrateincreasedto30/min.Hisminuteventilationalsoincreasedfrom8.5l/minto20l/min.Airwaypressureincreasedfrom18to65cmH2O.RepeatarterialbloodgasmeasurementofPO2indicated35mmHgandchestx-raynowshoweddiffuseinfiltratesina"whiteout"pattern.ThediagnosisofARDSiscontingentupon5factors:1.Hypoxemia,2.Diffusepulmonaryinfi