ARDS患者的肺复张.ppt

ARDS患者的肺复张 北京协和医院杜斌 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 ARDS的肺保护性通气策略 ARDS的肺保护性通气策略 小潮气量 6ml kgIBW 避免过度膨胀造成的容积伤 volutrauma 足够的PEEP防止肺泡复张造成的剪切力损伤 atelectrauma 肺泡塌陷与复张造成的剪切力 F PLx V0 V 2 3F 剪切力PL 跨肺压V0 最初容积V 复张后容积如果 PL 30cmH2O V0 V 1 10则 F 140cmH2O MeadJ TakishimaT LeithD Stressdistributioninlungs amodelofpulmonaryelasticity JApplPhysiol1970 28 5 596 608 小潮气量通气的问题 RichardJC MaggioreSM JonsonB ManceboJ LemaireF BrochardL InfluenceofTidalVolumeonAlveolarRecruitment RespectiveRoleofPEEPandaRecruitmentManeuver AmJRespirCritCareMed2001 163 1609 1613 小潮气量通气的问题 RichardJC MaggioreSM JonsonB ManceboJ LemaireF BrochardL InfluenceofTidalVolumeonAlveolarRecruitment RespectiveRoleofPEEPandaRecruitmentManeuver AmJRespirCritCareMed2001 163 1609 1613 小潮气量通气的问题 RichardJC MaggioreSM JonsonB ManceboJ LemaireF BrochardL InfluenceofTidalVolumeonAlveolarRecruitment RespectiveRoleofPEEPandaRecruitmentManeuver AmJRespirCritCareMed2001 163 1609 1613 受损的肺组织如何复张 俯卧位足够的PEEP足够的潮气量 和 或 叹气 肺复张手法减少水肿 最低可接受的FiO2 自主呼吸 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 肺泡的开放压与闭合压 PEEP不能使肺复张 LIP 仅仅是肺复张的开始 HicklingKG Thepressure volumecurveisgreatlymodifiedbyrecruitment AmathematicalmodelofARDSlungs AmJRespirCritCareMed1998 158 194 202 JonsonB RichardJC StrausC ManceboJ LemaireF BrochardL Pressure VolumeCurvesandComplianceinAcuteLungInjury EvidenceofRecruitmentAbovetheLowerInflectionPoint AmJRespirCritCareMed1999 159 1172 1178 低位转折点之上仍有肺组织复张 肺泡的开放压与闭合压 肺泡开放压与闭合压 Paw cmH2O CrottiS MascheroniD CaironiP PelosiP RonzoniG MondinoM MariniJJ GattinoniL Recruitmentandderecruitmentduringacuterespiratoryfailure aclinicalstudy AmJRespirCritCareMed2001 164 131 140 ARDS的肺开放 EditorialOpenupthelungandkeepthelungopenB LachmannDept ofAnesthesiology ErasmusUniversityRotterdam TheNetherlands 1992 18 319 321 RM能够使肺开放 RM PIP45cmH2O PEEP35cmH2Ox1min HalterJM SteinbergJM SchillerHJ DaSilvaM GattoLA LandasS NiemanGF PositiveEnd ExpiratoryPressureafteraRecruitmentManeuverPreventsBothAlveolarCollapseandRecruitment Derecruitment AmJRespirCritCareMed2003 167 1620 1626 肺复张能够改善ARDS氧合 LapinskySE AubinM MehtaS BoiteauP SlutskyAS Safetyandefficacyofasustainedinflationforalveolarrecruitmentinadultswithrespiratoryfailure IntensiveCareMed1999 25 1297 1301 肺复张的各种方法 CPAP SI incrementalPEEPPCVSigh modified HFOV俯卧位 SI改善氧合 TugrulS AkinciO OzcanPE Ince S EsenF TelciL AkpirK CakarN Effectsofsustainedinflationandpostinflationpositiveendexpiratorypressureinacuterespiratorydistresssyndrome Focusingonpulmonaryandextrapulmonaryforms CritCareMed2003 31 738 744 SustainedInflation 45cmH2Ox30s SI改善氧合 FrankJA McAuleyDF GutierrezJA DanielBM DobbsL MatthayMA Differentialeffectsofsustainedinflationrecruitmentmaneuversonalveolarepithelialandlungendothelialinjury CritCareMed2005 33 181 188 SustainedInflation 30cmH2Ox30sTwicewith1mininterval 叹气的设置 LimCM KohY ParkW ChinJY ShimTS LeeSD KimWS KimDS KimWD Mechanisticschemeandeffectofextendedsighasarecruitmentmaneuverinpatientswithacuterespiratorydistresssyndrome Apreliminarystudy CritCareMed2001 29 1255 1260 充气阶段 每30秒PEEP增加5cmH2OVt减少2ml kg前2次呼吸除外直至Vt2ml kg PEEP25cmH2O暂停阶段CPAP30cmH2Ofor30s放气阶段 叹气改善氧合 LimCM KohY ParkW ChinJY ShimTS LeeSD KimWS KimDS KimWD Mechanisticschemeandeffectofextendedsighasarecruitmentmaneuverinpatientswithacuterespiratorydistresssyndrome Apreliminarystudy CritCareMed2001 29 1255 1260 叹气对氧合及呼吸力学的影响 PelosiP CadringherP BottinoN PanigadaM CarrieriF RivaE LissoniA GattinoniL Sighinacuterespiratorydistresssyndrome AmJRespirCritCareMed1999 159 872 880 Sigh 3consecutivesighs minatPplat45cmH2O 叹气的设置 PatronitiN FotiG CortinovisB MaggioniE BigatelloLM CeredaM PesentiA SighImprovesGasExchangeandLungVolumeinPatientswithAcuteRespiratoryDistressSyndromeUndergoingPressureSupportVentilation Anesthesiology2002 96 788 94 Baseline PSVSigh BIPAPPEEPhigh 1 2xPIPpsvor35cmH2OTi s 3 5sf 1bpm 叹气改善呼吸力学及氧合 PatronitiN FotiG CortinovisB MaggioniE BigatelloLM CeredaM PesentiA SighImprovesGasExchangeandLungVolumeinPatientswithAcuteRespiratoryDistressSyndromeUndergoingPressureSupportVentilation Anesthesiology2002 96 788 94 ARDS对RM的反应 VillagraA OchagaviaA VatusS MuriasG FernandezMF AguilarJL FernandezR BlanchL RecruitmentManeuversduringLungProtectiveVentilationinAcuteRespiratoryDistressSyndrome AmJRespirCritCareMed2002 165 165 170 肺复张 CT的提示 HenzlerD MahnkenAH WildbergerJE RossaintR G ntherRW KuhlenR Multislicespiralcomputedtomographytodeterminetheeffectsofarecruitmentmaneuverinexperimentallunginjury EurRadiol2006 16 1351 1359 肺复张 CT的提示 HenzlerD MahnkenAH WildbergerJE RossaintR G ntherRW KuhlenR Multislicespiralcomputedtomographytodeterminetheeffectsofarecruitmentmaneuverinexperimentallunginjury EurRadiol2006 16 1351 1359 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 RMvs PEEP LimCM LeeSS LeeJS KohY ShimTS LeeSD KimWS KimDS KimWD MorphometricEffectsoftheRecruitmentManeuveronSaline lavagedCanineLungs AComputedTomographicAnalysis Anesthesiology2003 99 71 80 RMvs PEEP LimCM LeeSS LeeJS KohY ShimTS LeeSD KimWS KimDS KimWD MorphometricEffectsoftheRecruitmentManeuveronSaline lavagedCanineLungs AComputedTomographicAnalysis Anesthesiology2003 99 71 80 RMvs PEEP LimCM LeeSS LeeJS KohY ShimTS LeeSD KimWS KimDS KimWD MorphometricEffectsoftheRecruitmentManeuveronSaline lavagedCanineLungs AComputedTomographicAnalysis Anesthesiology2003 99 71 80 RMvs PEEP LimCM LeeSS LeeJS KohY ShimTS LeeSD KimWS KimDS KimWD MorphometricEffectsoftheRecruitmentManeuveronSaline lavagedCanineLungs AComputedTomographicAnalysis Anesthesiology2003 99 71 80 RMvs PEEP LimCM LeeSS LeeJS KohY ShimTS LeeSD KimWS KimDS KimWD MorphometricEffectsoftheRecruitmentManeuveronSaline lavagedCanineLungs AComputedTomographicAnalysis Anesthesiology2003 99 71 80 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 为什么肺复张作用不能持久 OczenskiW H rmannC KellerC LorenzlN KepkaA SchwarzS FitzgeraldRD RecruitmentManeuversafteraPositiveEnd expiratoryPressureTrialDoNotInduceSustainedEffectsinEarlyAdultRespiratoryDistressSyndrome Anesthesiology2004 101 620 5 为什么肺复张作用不能持久 肺复张的方法 SI 50cmH2Ox30s作者认为 OczenskiW H rmannC KellerC LorenzlN KepkaA SchwarzS FitzgeraldRD RecruitmentManeuversafteraPositiveEnd expiratoryPressureTrialDoNotInduceSustainedEffectsinEarlyAdultRespiratoryDistressSyndrome Anesthesiology2004 101 620 5 RM PEEPvs RMvs PEEP LimCM JungH KohY LeeJS ShimTS LeeSD KimWS KimDS KimWD Effectofalveolarrecruitmentmaneuverinearlyacuterespiratorydistresssyndromeaccordingtoantiderecruitmentstrategy etiologicalcategoryofdiffuselunginjury andbodypositionofthepatient CritCareMed2003 31 411 418 RM PEEPvs RMvs PEEP LimCM JungH KohY LeeJS ShimTS LeeSD KimWS KimDS KimWD Effectofalveolarrecruitmentmaneuverinearlyacuterespiratorydistresssyndromeaccordingtoantiderecruitmentstrategy etiologicalcategoryofdiffuselunginjury andbodypositionofthepatient CritCareMed2003 31 411 418 RM PEEP RMonly RM后的PEEP RM后的PEEP能够稳定肺泡 HalterJM SteinbergJM SchillerHJ DaSilvaM GattoLA LandasS NiemanGF PositiveEnd ExpiratoryPressureafteraRecruitmentManeuverPreventsBothAlveolarCollapseandRecruitment Derecruitment AmJRespirCritCareMed2003 167 1620 1626 RM后的PEEP能够稳定肺泡 RM PIP45cmH2O PEEP35cmH2Ox1min PEEP5cmH2O PEEP10cmH2O HalterJM SteinbergJM SchillerHJ DaSilvaM GattoLA LandasS NiemanGF PositiveEnd ExpiratoryPressureafteraRecruitmentManeuverPreventsBothAlveolarCollapseandRecruitment Derecruitment AmJRespirCritCareMed2003 167 1620 1626 肺泡稳定能够改善PaO2 McCannUG SchillerHJ GattoLA etal Alveolarmechanicsalterhypoxiculmonaryvasoconstriction CritCaremed2002 30 1315 1321 RM后的PEEP LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 RM PEEPvs PEEPonly LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 RM PEEP PEEPonly PEEP的设置 RM之后通常将PEEP设置在能够维持PaO2 防止塌陷 的水平最初将PEEP设置为20cmH2O然后将FiO2减小到最低水平维持SpO290 95 每20 30分钟降低PEEP2cmH2O直至患者SpO2下降 PEEP的设置 氧合下降前的PEEP水平防止大部分肺泡塌陷的PEEP一旦确认 则需重复肺复张操作 然后把PEEP和FiO2重新设置在上述水平对于多数ARDS患者 PEEP介于15 20cmH2O之间某些患者20cmH2O PEEP的设置 如果将PEEP设置于20cmH2O后 仍发现PaO2 FiO2显著下降按照最初的PEEP设置25cmH2O重复肺复张然后按照上述方法调节FiO2和PEEP PEEP的设置 将PEEP从不必要的高水平逐渐降低不要将PEEP由低水平增加到高水平如同P V曲线所示 根据设置方法不同 同样水平的PEEP所维持的肺容积不同如果在肺泡塌陷后设置PEEP 增加PEEP 则所设置的PEEP水平可以使肺容积减少 PaO2降低 PEEP FiO2的调整 推荐意见降低PEEP之前应当首先降低FiO2 以避免肺泡塌陷一般情况下FiO2应当减低到 0 45如果降低PEEP导致氧合下降应当重新设定PEEP肺泡塌陷时不应增加FiO2 肺复张后氧合稳定所需时间 TugrulS CakarN AkinciO OzcanPE DisciR EsenF TelciL TAkpir Timerequiredforequilibrationofarterialoxygenpressureaftersettingoptimalpositiveend expiratorypressureinacuterespiratorydistresssyndrome CritCareMed2005 33 995 1000 LIP 2 肺复张后氧合稳定所需时间 TugrulS CakarN AkinciO OzcanPE DisciR EsenF TelciL TAkpir Timerequiredforequilibrationofarterialoxygenpressureaftersettingoptimalpositiveend expiratorypressureinacuterespiratorydistresssyndrome CritCareMed2005 33 995 1000 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 不同RM方法的比较 基础通气方式VCV Vt10ml kg f20bpm I E1 2 FiO20 5肺复张 OdenstedtH LindgrenS OlegardC ErlandssonK LethvallS AnemanA StenqvistO LundinS Slowmoderatepressurerecruitmentmaneuverminimizesnegativecirculatoryandlungmechanicsideeffects evaluationofrecruitmentmaneuversusingelectricimpedancetomography IntensiveCareMed2005 31 1706 1714 不同RM方法的比较 OdenstedtH LindgrenS OlegardC etal Slowmoderatepressurerecruitmentmaneuverminimizesnegativecirculatoryandlungmechanicsideeffects evaluationofrecruitmentmaneuversusingelectricimpedancetomography IntensiveCareMed2005 31 1706 1714 不同RM方法的比较 OdenstedtH LindgrenS OlegardC ErlandssonK LethvallS AnemanA StenqvistO LundinS Slowmoderatepressurerecruitmentmaneuverminimizesnegativecirculatoryandlungmechanicsideeffects evaluationofrecruitmentmaneuversusingelectricimpedancetomography IntensiveCareMed2005 31 1706 1714 不同RM方法的比较 对于灌洗造成的急性肺损伤模型缓慢低压复张操作可以促进肺泡复张减少对循环系统的抑制避免对呼吸力学的不良影响 OdenstedtH LindgrenS OlegardC ErlandssonK LethvallS AnemanA StenqvistO LundinS Slowmoderatepressurerecruitmentmaneuverminimizesnegativecirculatoryandlungmechanicsideeffects evaluationofrecruitmentmaneuversusingelectricimpedancetomography IntensiveCareMed2005 31 1706 1714 不同RM方法的比较 LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 Sustainedinflation45for40s IncrementalPEEPPIP35 PEEP8 35 PCVPIP45 PEEP16I E1 2 2min 对于VILI模型PCV是最佳的RM方法其他模型结果相似 PEEP8 PEEP12 PEEP16 LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 RM保护肺内皮而非肺泡上皮 试验动物 大鼠模型制备 酸 pH1 5 吸入机械通气 Vt6ml kgPEEP5cmH2OFiO21 0F60 70bpm复张操作 30cmH2Ox30sx2间隔1分钟 FrankJA McAuleyDF GutierrezJA DanielBM DobbsL MatthayMA Differentialeffectsofsustainedinflationrecruitmentmaneuversonalveolarepithelialandlungendothelialinjury CritCareMed2005 33 181 188 RM保护肺内皮而非肺泡上皮 FrankJA McAuleyDF GutierrezJA DanielBM DobbsL MatthayMA Differentialeffectsofsustainedinflationrecruitmentmaneuversonalveolarepithelialandlungendothelialinjury CritCareMed2005 33 181 188 RM ARDS早期vs 晚期 VillagraA OchagaviaA VatusS MuriasG FernandezMF AguilarJL FernandezR BlanchL RecruitmentManeuversduringLungProtectiveVentilationinAcuteRespiratoryDistressSyndrome AmJRespirCritCareMed2002 165 165 170 原发性ARDS对RM反应不佳 Salinelavage Oleicacidinjury Pneumonia VanderKlootTE BlanchL YoungbloodAM WeinertC AdamsAB MariniJJ ShapiroRS NahumA RecruitmentManeuversinThreeExperimental ModelsofAcuteLungInjuryEffectonLungVolumeandGasExchange AmJRespirCritCareMed2000 161 1485 1494 SustainedinflationCPAP40 30CPAP60 30CPAP60 30 油酸损伤模型RM作用短暂 LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 PEEP8 PEEP12 PEEP16 不同病因对RM的反应 LimCM AdamsAB SimonsonDA DriesDJ BroccardAF HotchkissJR MariniJJ Intercomparisonofrecruitmentmaneuverefficacyinthreemodelsofacutelunginjury CritCareMed2004 32 2371 2377 RM PEEP PEEPonly RM ARDSp与ARDSexp LimCM JungH KohY LeeJS ShimTS LeeSD KimWS KimDS KimWD Effectofalveolarrecruitmentmaneuverinearlyacuterespiratorydistresssyndromeaccordingtoantiderecruitmentstrategy etiologicalcategoryofdiffuselunginjury andbodypositionofthepatient CritCareMed2003 31 411 418 SI改善氧合 TugrulS AkinciO OzcanPE Ince S EsenF TelciL AkpirK CakarN Effectsofsustainedinflationandpostinflationpositiveendexpiratorypressureinacuterespiratorydistresssyndrome Focusingonpulmonaryandextrapulmonaryforms CritCareMed2003 31 738 744 SustainedInflation 45cmH2Ox30s 叹气 ARDSp与ARDSexp PelosiP CadringherP BottinoN PanigadaM CarrieriF RivaE LissoniA GattinoniL Sighinacuterespiratorydistresssyndrome AmJRespirCritCareMed1999 159 872 880 Sigh 3consecutivesighs minatPplat45cmH2O 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 RM不增加肺泡过度膨胀 BugedoG BruhnA HernandezG etal Lungcomputedtomographyduringalungrecruitmentmaneuverinpatientswithacutelunginjury IntensiveCareMed2003 29 218 225 肺复张对内脏血流的影响 NunesS RothenHU BranderL TakalaJ JakobSM ChangesinSplanchnicCirculationDuringanAlveolarRecruitmentManeuverinHealthyPorcineLungs AnesthAnalg2004 98 1432 8 肺复张对胃肠道血流的影响 ClaessonJ LehtipaloS WinsoD Dolungrecruitmentmaneuversdecreasegastricmucosalperfusion IntensiveCareMed2003 29 1314 1321 肺复张对脑氧代谢的影响 BeinT KuhrLP BeleS PlonerF KeylC TaegerK Lungrecruitmentmaneuverinpatientswithcerebralinjury effectsonintracranialpressureandcerebralmetabolism IntensiveCareMed2002 28 554 558 内容 小潮气量通气的问题肺复张的理论与实践肺复张与PEEP肺复张后的PEEP不同复张方法的差异肺复张的临床适应症肺复张的副作用肺复张存在的问题 肺泡开放压与闭合压 Paw cmH2O CrottiS MascheroniD CaironiP PelosiP RonzoniG MondinoM MariniJJ GattinoniL Recruitmentandderecruitmentduringacuterespiratoryfailure aclinicalstudy AmJRespirCritCareMed2001 164 131 140 即使使用足够的PEEP也不能使所有肺单位开放 RM对哪些患者疗效好 尚不清楚肺复张对哪类患者疗效更好肺复张对早期ARDS ALI患者的效果更显著随着ARDS的进展 肺进入纤维增殖期肺复张就无法有效改善氧合气压伤的危险反而增加 RM对哪些患者疗效好 ARDS的病因继发性ARDS 全身性感染 创伤等 比原发性ARDS 肺炎 更容易复张目前的推荐意见在ARDS ALI病程早期进行肺复张无论ARDS的病因如何 肺复张操作的频率 尚不清楚对某一患者进行肺复张操作的适宜频率以下情况应进行肺复张操作病程早期当肺泡塌陷时例如呼吸机脱开 肺复张操作的频率 对于ARDS患者脱离呼吸机能够导致肺泡迅速塌陷 从而发生严重的低氧血症为避免呼吸机脱开 建议采用密闭吸痰装置特殊雾化装置 肺复张操作的频率 肺复张操作当观察到SpO2持续降低 5min 时如果没有观察到氧合下降 则需要每日进行一次或两次肺复张未知 总结 肺复张是肺保护性通气策略的重要组成开放肺并维持肺开放是其理论基础应用气道高压使塌陷肺泡开放应用足够的PEEP维持肺泡开放肺复张对循环的影响肺复张尚未解决的问题压力时间频率适应症 PEEP能否使肺复张 PEEP能够防止肺泡塌陷 derecruitment 低水平的PEEP只能使很少的肺复张对于ARDS 将压力持续维持在常用的PEEP水平 20cmH2O 只能使小部分肺组织复张 PEEP能否使肺复张 ARDS患者的肺复张贯穿于整个吸气过程byHicklingAJRCCM1998TidalrecruitmentoccursbelowoptimalPEEP PEEPattheoptimallevelgenerallyresultsinadecreasedquasi staticcompliancewhenmeasuredontheventilatorbyJonsonetalAJRCCM1999 肺复张所需的压力 正常潮气量通气也能使肺组织复张但是 大部分肺组织可能仍未充分复张在有限的吸气时间内在目标气道峰压水平由于塌陷肺泡表面液体的粘滞性这些肺单位较高的表面张力间质组织的限制塌陷的肺组织需要较高的气道压力和较长的时间才能复张 Howhighapressure Howlongatime healthylung transpulmonarypressureof30cmH2OtorecruitatelectatichealthylungsGreavesetalJAP1990peakalveolarpressuresof40cmH2Ofor7to15secondstorecruitlungsofpreviouslyhealthynormalpatientsfollowing20minutesofgeneralanesthesiabyRothenetalBrJAnaesth1993 1998resolutionofatelectasisduringa40cmH2ORMhasatimeconstantof2 6secRothenetalBrJAnaesth1999 Howhighapressure Howlongatime healthylung Asaresultinpreviouslyhealthyindividualsthevastmajorityofatelectasiswouldberecruitedwithinabout7 8sec Howhighapressure Howlongatime animal peakairwaypressuresof55cmH2Ofor5 10mintoopencollapsedlunginaporcinemodelofARDSSjosrandetalICM1995tomaximallyrecruitlunginasheepsalinelavagelunginjuredmodel40cmH2OPEEP 20cmH2OPC Ppeak60cmH2O I Eof1 1 andarateof10bpmfor2minutesFujinoetalAJRCCM1999 Howhighapressure Howlongatime animal animalsrecruitedwith40cmH2OCPAPfor60secnotmaximallyrecruitedtofullyrecruitthelungmultiple 2 3 RMsrequiredevenatpeakpressuresof60cmH2O Howhighapressure Howlongatime patient peakairwaypressureof46cmH2OtorecruitcollapsedlunginARDSpatientsGattinonietalAJRCCM198635 40cmH2OCPAPfor30 40secpriortoestablishingalungprotectiveventilatorystrategywhenevermechanicalventilationwasdisruptedAmatoetalNEJM1998 Howhighapressure Howlongatime patient InapatientwithsepticARDSinitialrecruitmentmaneuverswith40cmH2OCPAPfor40secfailedPEEP40cmH2OPEEPandPCV20cmH2OatanI Eratioof1 1witharateof10bpmfor2minutestofullyrecruitthelungMedoffetalCCM2000 Howhighapressure Howlongatime patient ThesuccessofPCvsCPAPintheexamplesemphasizetherelationshipbetweenpressureandtimeFujinoetalAJRCCM1999MedoffetalCCM2000Theoptimalrelationshipbetweenthesetwovariablestomaximizeefficacyandmaintainsafetyremainsunclear Mechanismoflungrecruitment First theairwaysmustbeopenedinordertorecruitcollapsedlungAirwayopeningoccursbyeithermovingthemeniscusformedbyfluidliningtheairwaytowardtheperipheryorovercomingtheparenchymatetheringpresentinactualcollapsedairway Mechanismoflungrecruitment Second thecollapsedalveolimustbeopenedcollapsedinjuredlungunitswithincreasedsurfacetensionrequireveryhighpressurestoestablishsufficientlateralstresstoopenthelungMeadetalJAP1970 Whatisclearisthattheoptimalmethodoflungrecruitmentinsuringmaximalefficacyandsafetyhasnotbeendetermined SideEffectsofRMs hemodynamiccompromisedelayeduntilpatientshemodynamicallystabledevelopmentofbarotraumathebenefitsandpotentialrisksmustbecarefullyweighedinpatientswithpreexistingpulmonarycysticorbullouslungdiseasepreexistingairleaks MonitoringofPatients arterialpressurepulserateandrhythmSpO2ifcompromisedevelopstherecruitmentmaneuveraborted PerformanceofaRM FIO2increasedto1 0for5 10minutesbeforeRMsedationgenerallyrequiredtoinsurepassiveinflationduringtherecruitmentperiod30cmH2OCPAPfor30 40secduringthefirstRMfollowedbycarefulassessmentoftheresults PerformanceofaRM IftheresponseisinadequatebutpatienttoleranceisgoodRMshouldberepeatedin15 20minutesatahigherCPAPlevel 35 40cmH2O IftheresponsetothesecondRMisinadequateathirdRM