ARDS肺复张的测定-邱海波VIP免费

急性呼吸窘迫综合征肺复张的测定与应用邱海波东南大学附属中大医院东南大学急诊与危重病研究所内容提要ARDS病理生理ARDS肺复张容积测定P-V曲线法等压法CT法：Gattinoni’svsRouby’sARDS肺复张测定应用明确肺不张的分布与特点评价SIorSigh的肺复张作用评价PEEP维持肺复张的作用指导PEEP选择•Lungvolumedecreasedmarkedly(TLC,VC,TV,FRC)---alveolaredema---pulmonarysurfactant---Interstitialpumonaryedemadepressbrochioleandinducespasm•Compliancereducedsignificantly•Ventilation/perfusionmismatch---intrapulmonaryshuntanddeadspacelikeeffectsARDS病理生理特点ARDS病理生理CTscan70-80%的肺野呈现高密度区分布：下垂部位(dependentfield)提示：参与通气肺泡明显减少(20-30%)肺损伤具有不均一性肺容积减少—SmalllungBabyLungARDS病理生理AandCfindingintheacuteorexudativephaseBandDFindinginthefibrosing-alveolitisphaseARDS病理生理肺容积/顺应性明显降低ARDS病理生理•Reducedrangeofvolumeexcursion:Lowcompliance•Flatteningatlowandhighvolumes:Lowerandupperinflectionpoints•Bigatello:BrJAnaest1996VolumePressureNORMALARDS顺应性曲线明显右下移位肺顺应性明显降低ARDS病理生理UpperandLowerInflectionPointsLower呼气末肺泡塌陷吸气早期肺泡再开放Upper吸气末肺泡顺应性明显降低，肺泡过度膨胀ARDS病理生理VolumePressureLowerInflectionPointLowerInflectionPointUpperInflectionPoint通气/血流失调肺泡塌陷：ARDS重力依赖区，炎症或不张区生理性低氧缩血管反应：障碍ARDS病理生理ImaginetheHardnesstoBlowupaBallon...VPeasyhardspatial&elasticlimitationsLaplacianLawItneedshigherinitialpressurestoovercomethesurfacetensiontoopenupabubbletowiderdiameters!Itneedshigherinitialpressurestoovercomethesurfacetensiontoopenupabubbletowiderdiameters!ARDS病理生理SustaininflationSigh小潮气量通气—PHC,避免肺泡过度膨胀最佳PEEP－避免剪切力(Shearforce)性损害VolumePressure肺开放与保护性通气策略的基本内容ARDS病理生理LungvolumedecreasedmarkedlyAtelectraumaKeepthelungKeepthelungopenopenOpenthelungOpenthelungPreventvolutraumaSIandSighPEEPARDS病理生理内容提要ARDS病理生理ARDS肺复张容积测定P-V曲线法等压法CT法：Gattinoni’svsRouby’sARDS肺复张测定应用明确肺不张的分布与特点评价SIorSigh的肺复张作用评价PEEP维持肺复张的作用指导PEEP选择P－V曲线法Step1:测量PEEP所致的FRC(吸气末撤掉PEEP并延长呼气时间)FRC＝VE(ZEEP)－VE(PEEP)肺复张容积测定P－V曲线法Step2:分别描计ZEEP和PEEP的P－V曲线Step3:肺复张容积：RV=V20(PEEP)+FRCV20(ZEEP)肺复张容积测定等压法呼吸模式：BIPAP条件：Ph20cmH2O，PEEP分别为0、5、10、15cmH2O，Ti6S测定：延长呼气时间，测定ZEEP呼出气量。在不同PEEP时吸气末撤掉PEEP，延长呼气时间，测定呼气量肺复张容积测定等压法肺复张容积测定010020030040050051015PEEP水平(cmH2O)复张容积(ml)P-V法等压法P-V曲线法与等压法的比较***#与PEEP5cmH2O相比较，*P<0.05;与PEEP10cmH2O相比，P<0.05;与P-V曲线法相比，#P<0.05*#肺复张容积测定肺复张容积测定—P-V曲线法等压法虽然简单，但准确性较差不能代替P-V曲线法目前肺复张容积的测定仍宜采用P-V曲线法肺复张容积测定CTmethod膈顶上1cmCT层面PEEP与ZEEP比较GattinoniL.AmJRespirCCM,1995,151:1807全肺扫描区别过度膨胀，膨胀，部分复张和塌陷区LuizM,RoubyJJ.AmJRespirCCM,2001,163:1444肺复张容积测定CT法--Gattinoni肺复张容积测定原理•CT空气=0Hu，CT水=1000Hu•CT值=500Hu，肺组织50%空气+50%水•ARDS塌陷肺CT值100Hu~100Hu，塌陷肺泡复张后，100Hu~+100Hu内肺组织减少方法•ZEEP和PEEP通气呼气末CT扫描•膈肌顶上1cm•计算CT值在100Hu~100Hu范围内体素结果之差GattinoniL.AmJRespirCCM,1995,151:1807原理充气不良区(100...