2015年ARDS-通气策略(宋立强)

西京医院呼吸与危重医学科宋立强PulmonaryProtectiveVentilationInARDS急性呼吸窘迫综合征（AcuteRespiratoryDistressSyndrome，ARDS）心源性以外的各种肺内外致病因素急性、进行性缺氧性呼吸衰竭导致1肺间质2肺泡ARDS是一种水循环障碍的“肺水肿”“肺水肿”分类(按照病因及发生机制)1.感染性肺水肿(pulmonaryedemaduetoinfection)2.毒素吸入性肺水肿(pulmonaryedemaduetopoison)3.淹溺性肺水肿(pulmonaryedemaduetodrowning)4.尿毒症性肺水肿(pulmonaryedemainuremia)5.氧中毒肺水肿(pulmonaryedemaduetooxygentoxicity)②通透性肺水肿——病因及分类ARDS肺水肿的成分：富含蛋白细胞碎片未激活的PS中性粒细胞巨噬细胞炎症介质......参与反应的细胞——中性粒细胞巨噬细胞上皮细胞内皮细胞参与反应的介质——氧自由基蛋白溶解酶花生四烯酸代谢物补体系统凝血和纤溶系统PAFTNFIL......ARDS发病的炎症机制ApexHilumBase病变分布有重力依赖性，从肺前部到背部——1.正常区30%2.陷闭区20~30%3.实变区40~50%病理生理变化——1.间歇性分流2.切变力损伤3.肺循环阻力增加病理生理变化——1.持续性分流2.肺循环阻力增加力学曲线变化——1967年，Ashbaugh等首先描述“成人中的急性呼吸窘迫”1971年，Petty等正式命名“成人呼吸窘迫综合征（ARDS）”1992年，美欧共识会（American-EuropeanConsensusConference,AECC）急性呼吸窘迫综合征（AcuteRespiratoryDiseaseSyndrome，ARDS）首次提出ALI提出AECC标准AECC标准局限性病程急性起病无具体时间ALIPaO2/FiO2≤300mmHg误解201-300mmHg为ALI氧合指数PaO2/FiO2≤200mmHg，未考虑PEEP水平不同的PEEP及FiO2，PaO2/FiO2也不同胸片双肺弥漫性浸润缺乏客观评价指标PAWPPAWP≤18mmHg，无左心房高压ARDS及高水平PAWP可同时存在，PAWP有不确定性AECC诊断标准的局限AnearlyPEEP/FIO2trialidentifiesdifferentdegreesoflunginjuryinpatientswithacuterespiratorydistresssyndrome.AmJRespirCritCareMed.2007；15;176(8):795-804.在（day1）时间点FiO2≥0.5+PEEP≥10，30min条件下——重新分类为ARDS,ALI,ARF29%ARDS患者PAWP≥18mmHg（或CVP升高）,而其中97%PAWP升高的ARDS患者中有正常的心脏功能。结论：PAWP或CVP升高不能作为ARDS的排除标准。Pulmonary-arteryversuscentralvenouscathetertoguidetreatmentofacutelunginjury.NEnglJMed.2006May25;354(21):2213-24.CVPPAWP818BerlinDefinition2012柏林定义ARDS的诊断及病情分级1.发病时间1周以内起病、或新发、或恶化的呼吸症状2.胸部影像学双肺模糊影——不能完全由渗出、肺塌陷或结节来解释3.肺水肿起因不能完全由心力衰竭或容量过负荷解释的呼吸衰竭，没有发现危险因素时可行超声心动图等检查排除血流源性肺水肿4.氧合指数轻度200mmHgPaO2/FiO2≤300mmHgwithPEEP≥5cmH2O中度100mmHgPaO2/FiO2≤200mmHgwithPEEP≥5cmH2O重度PaO2/FiO2≤100mmHgwithPEEP≥5cmH2OOverdistention过度扩张Barotrauma压力伤Volutrauma容量伤Recruitment/DerecruitmentInjury（Atlectrauma）剪切伤/萎陷伤TranslocationofCells细胞形态移位Biotrauma生物伤OxidantInjury氧中毒“Shear”Recruitment/DerecruitmentInjury跨肺压若用30cmH2O的正压通气，则跨肺压约35cmH2O。两个肺单位之间产生高达140cmH2O的切变力。Bilek,A.M....D.P.GaverIIIJApplPhysiol94:770-783,2003DisruptingthealveolarepitheliumTearingincapillaryendotheliumIncitingEventPMNs/MacsEndotheliumEpitheliumAdhesionProteasesO2radicalsCoagulationProteinsCytokinesIL-6IL-8IL-10IL-8-RATNF-aENA-78MIP-1aTransferrinPAFComplementLPBLTB4LTC4②BiophysicalInjury•shear•overdistention•cyclicstretch•Dintrathoracicpressurealveolar-capillarypermeabilitycardiacoutputorganperfusion①BiochemicalInjury(Biotrauma)mfcytokines,complement,PGs,LTs,ROS,proteasesbacteriaEpithelium/interstitiumneutrophilsDistalOrganDysfunctionMechanicalVentilationSlutsky,TremblayAmJRespCritCareMed.1998;157:1721-5DEATHOxidantinjury-keepFiO260Barotrauma-keepalveolarinflationpressures35cmH2OVolutrauma-BabylungconceptorstretchinjuryAtelectrauma-repeatedopeningandclosingBiotrauma-releaseofinflammatorymediatorsandbacterialtranslocationOPENGENTLYANDKEEPTHEMOPEN温柔的打开肺泡，并保持开放WhiteheadT,SlutskyAS.Thorax.2002;57:636①小潮气量（6ml／kg理想体重）②允许性高碳酸血症③控制气道平台压30cmH2O④使用合适的PEEP是迄今为止少有的被大规模随机对照研究证实，能降低ARDS患者死亡率的治疗措施。提高治疗干预强度轻度ARDS中度ARDS严重ARDS小潮气量通气更高水平PEEP无创通气低-中水平PEEP俯卧位通气神经肌肉阻滞剂高频振荡通气ECCO2-RECMO30025020015010050TidalvolumePlateaupressurespHPEEPVCvsPCVRecruitmentmaneuversHigh-frequencyoscillatoryPronepositioningECMO潮气量平台压允许性高碳酸血症呼气末正压定容与定压手法复张高频振荡通气俯卧位通气体外膜氧合肺通气保护策略在儿童ARDS中的应用2000年《NEJM》，861名成人ARDS患者治疗组：小潮气量（4-6ml/kg）,限制压力（平台压30cmH2O），允许性高碳酸血症但保持pH大于7.3显著改善预后病死率39.8%―→31%自主呼吸天数10天―→12天首次为小潮气量通气模式提供可靠的循证医学证据ARDSNet.2000HagerDNetal.TidalVolumeReductioninPatientswithAcuteLungInjuryWhenPlateauPressuresAreNotHigh.AJRCCM2005.Vol1721241-1245多个研究比较***死亡率787patientsfromARDSNetworkstudy平台压死亡率30PEEP：较高的呼气末正压(Meta)BrielM,MeadeM,MercatA,etal.Highervslowerpositiveend-expiratorypressureinpatientswithacutelunginjuryandacuterespiratorydistresssyndrome.JAMA2010;303(9):865–73.医院死亡率ICU死亡率气胸气胸后死亡脱机时间允许性高碳酸血症的通气策略33流程图起始选择与设置潮气量：VTof8mL/kgvsVTof10~15mL/kgPEEP：titratingPEEPashighaspossiblewithoutincreasingthemaximalPEItogreaterthan30cmH2OPurpose:Todeterminewhetherventilationwithlowtidalvolume(VT)andlimitedairwaypressureorhigherpositiveend-expiratorypressure(PEEP)improvesoutcomesforpatientswithARDSoracutelunginjury住院死亡率随访死亡率气压伤因严重低氧所致抢救性治疗的应用率抢救性治疗的死亡率第1天的PaO2routineuseoflowVTtendstobebeneficialinallpatientswithacutelunginjuryorARDSbecausethisventilationstrategyimprovedhospitalmortality.HigherPEEPstrategiesduringlowerVTventilationdidnotimprovehospitalmortalityandcannotberecommendedinunselectedpatientswithacutelunginjuryorARDS.HigherPEEPstrategiesduringlowerVTventilationmaypreventlife-threateninghypoxemia.PCV的优点:variableflowsomorecomfortableifdys-synchrony,prolongitimeforoxygenation,controlpeakpressuresRCTmulticenter,79patientswithARDSPCV(n-37)versusVCV(n=42).Pplat≤35cmH2ONodifferenceinmortalitytrendtomorerenalfailureinVCVgroupBUTpatientsinVCVgrouphadahigherin-housemortalityrelatedtohighernumberofextra-pulmonaryorganfailures(78%vs51%)（TV8cc/kgofweight）Arecentsystematicreviewanalyzed40studiesthatevaluatedRMs;（4wereRCTs,32prospectivestudies,and4retrospectivecohortstudies）Thesustainedinflationmethod