COPD患者的机械通气

COPD患者的机械通气北京协和医院杜斌利益冲突(ConflictsofInterest)TycoDraegerMaquetHamiltonTaemaViasysMechanicalVentilationofCOPD/Asthma|BinDuAECOPD的病理生理MechanicalVentilationofCOPD/Asthma|BinDuAirwayinflammationAirwaynarrowing&obstruction

FrictionalWOBShortenedmuscles,

curvatureAirtrappingAuto-PEEP

VE

musclestrength

Vt

VA

PaCO2

pH

PaO2

ElasticWOB

VCO2SteroidsAbxBDsMV?IPAPMV?IPAPMVPEEPAECOPD的病理生理机制呼气气流的驱动压降低肺弹性回缩力不明原因的异常下降呼气相吸气肌肉活动导致胸壁向外的回缩力异常升高气道阻力显著升高气道半径缩小呼气相声门裂狭窄后果肺过度充盈（FRC增加到正常值的2倍）呼吸系统时间常数增加MechanicalVentilationofCOPD/Asthma|BinDuPeressL,SybrechtG,MacklemPT.Themechanismofincreaseintotallungcapacityduringacuteasthma.AmJMed1976;61:165-169McCarthyDS,SigurdsonM.Lungelasticrecoilandreducedairflowinclinicallystableasthma.Thorax1980;35:298-302ColebatchHJ,FinucaneKE,SmithMM.Pulmonaryconductanceandelasticrecoilrelationshipsinasthmaandemphysema.JApplPhysiol1973;34:143-153CormierY,LecoursR,LegrisC.Mechanismsofhyperinflationinasthma.EurRespirJ1990;3:619-624CollettPW,BrancatisanoT,EngelLA.Changesintheglotticapertureduringbronchialasthma.AmRevRespirDis1983;128:719-723PepePE,MariniJJ.Occultpositiveend-expiratorypressureinmechanicallyventilatedpatientswithairflowobstruction:theauto-PEEPeffect.AmRevRespirDis1982;126:166-170RanieriVM,GrassoS,FioreT,GiulianiR.Auto-positiveend-expiratorypressureanddynamichyperinflation.ClinChestMed1996;17:379-394时间常数(τ)Tau呼气容积残余容积00%100%163.0%37.0%395.0%5.0%599.9%0.1%健康成人2x0.10=0.20”术后气管插管成人5x0.06=0.30”COPD成人15x0.06=0.90”ARDS成人8x0.03=0.24”ARDS患儿5x0.01=0.05”MechanicalVentilationofCOPD/Asthma|BinDu动态过度充盈的发病机制MechanicalVentilationofCOPD/Asthma|BinDuinspexpTimeVTVEETidalvolumeTrappedgasLungVolumeFRCObstructedLungsNormalStiffLungsLevyBD,KitchB,FantaCH.Medicalandventilatorymanagementofstatusasthmaticus.IntensiveCareMed1998,24:105-117.VEI=VT+VEE动态过度充盈的发病机制MechanicalVentilationofCOPD/Asthma|BinDuHubmayrRD,AbelMD,RehderK.Physiologicapproachtomechanicalventilation.CritCareMed1990;18:103-113动态过度充盈的监测吸气末肺容积(VEI)60”窒息过程中从吸气末至静态FRC的呼气容积需要完全肌松与其他指标相比预测气压伤并无优势autoPEEP低估实际autoPEEPPplat足够长的吸气暂停时间没有漏气MechanicalVentilationofCOPD/Asthma|BinDuOddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510Pplat的监测：吸气暂停时间MechanicalVentilationofCOPD/Asthma|BinDuBarberisL,MannoE,GuerinC.Effectofend-inspiratorypausedurationonplateaupressureinmechanicallyventilatedpatients.IntensivecareMed2003;29:130-134Pplat的监测：吸气暂停时间MechanicalVentilationofCOPD/Asthma|BinDuBarberisL,MannoE,GuerinC.Effectofend-inspiratorypausedurationonplateaupressureinmechanicallyventilatedpatients.IntensivecareMed2003;29:130-134autoPEEP与动态过度充盈MechanicalVentilationofCOPD/Asthma|BinDuOddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510肺泡通气：二室模型MechanicalVentilationofCOPD/Asthma|BinDuP2P1RcPiR1R2C1C2Rc=4R1=1.0R2=0.5C1=0.20C2=0.40P1(t)–P2(t)=kVk≈C1R1–C2R2C1+C2.VPiP1P2V1/V2k0.33.82.52.50.501.06.82.52.50.500Rc=4R1=0.5R2=5.0C1=0.01C2=0.40VPiP1P2V1/V2k0.36.35.13.60.041.012.48.43.50.06-5HubmayrRD,AbelMD,RehderK.Physiologicapproachtomechanicalventilation.CritCareMed1990;18:103-113COPD机械通气适应证呼吸肌疲劳且濒临呼吸停止尽管进行充分的保守治疗,PaCO2仍进行性升高劳累和(或)高碳酸血症导致意识状态恶化高浓度吸氧治疗无效的低氧血症痰液清除障碍导致病情恶化呼吸骤停MechanicalVentilationofCOPD/Asthma|BinDuCOPD机械通气的目的缓解呼吸肌疲劳改善气体交换，使其恢复至基础水平防止动态过度充盈和（或）auto-PEEP加重，以免导致循环功能衰竭MechanicalVentilationofCOPD/Asthma|BinDuCOPD机械通气策略控制性低通气(controlledhypoventilation)最先由Darioli和Perret于1984年提出不同于允许性高碳酸血症(permissivehypercapnia)严重气流梗阻患者难以纠正PaCO2增加分钟通气量可加重过度充盈及死腔纠正高碳酸血症效果有限MechanicalVentilationofCOPD/Asthma|BinDuLeathermanJW.Mechanicalventilationforsevereasthma.RespirCare2007;52:1460-1461确定COPD基础气体交换水平ABG考虑思路是否需要处理？平时PaCO2如何？既往结果的提示如果没有既往结果…MechanicalVentilationofCOPD/Asthma|BinDupH 7.202PaCO2 89.2mmHgPaO2 58.9mmHgSaO2 91.9%HCO3 37.9mmol/LBE 11.9mmol/LLA 2.2mmol/L确定COPD基础气体交换水平ABG考虑思路如何根据急性发作时ABG确定平时的PaCO2？pH≈PaCO2/HCO3pH≈40/24≈PaCO2/37.9MechanicalVentilationofCOPD/Asthma|BinDupH 7.202PaCO2 89.2mmHgPaO2 58.9mmHgSaO2 91.9%HCO3 37.9mmol/LBE 11.9mmol/LLA 2.2mmol/L确定COPD气体交换目标以PaCO2不低于基础水平为目标e.g.PaCO268mmHg,pH7.18@MinVent9lpm允许范围PaCO2<90mmHgpH>7.20MechanicalVentilationofCOPD/Asthma|BinDuLeathermanJW,McArthurC,ShapiroRS.Effectofprolongationofexpiratorytimeondynamichyperinflationinmechanicallyventilatedpatientswithsevereasthma.CritCareMed2004;32:1542-1545PaCO2的影响因素

VCO2

做功躁动癫痫

WOB

代谢发热CHO

T4

VA

VE

RR

Vt

Vd(不伴

VE)MechanicalVentilationofCOPD/Asthma|BinDuPaCO2≈VCO2MinVent(1–Vd/Vt)死腔增加时不应盲目增加分钟通气量MechanicalVentilationofCOPD/Asthma|BinDu

Vt

Palv

生理死腔MinVent

PEEP

ITPPaO2

PvO2

CO

休克COPD机械通气：减轻动态过度充盈降低潮气量减慢呼吸频率降低呼气阻力缩短吸气时间增加吸气流量使用硬质管路降低CO2产量MechanicalVentilationofCOPD/Asthma|BinDuStatherDR,StewartTE.Mechanicalventilationinsevereasthma.CritCare2005;9:581-587降低分钟通气量是避免气体闭陷最有效的方法AECOPD/哮喘机械通气初始设置呼吸参数设置模式VCV分钟通气量<10lpm潮气量6–10ml/kgPBW呼吸频率10–14bpm平台压<30cmH2O吸气流量60–80lpm吸气流量波形减速气流呼气时间4–5sPEEP0cmH2OFIO2SaO2>90%MechanicalVentilationofCOPD/Asthma|BinDuOddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510COPD机械通气模式的选择MechanicalVentilationofCOPD/Asthma|BinDuOddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510控制vs.辅助深度镇静+/-肌松以避免人机不同步定容vs.定压气道阻力和autoPEEP很高时，压力控制可能导致肺泡低通气气道梗阻迅速缓解时，压力控制可能导致呼吸性碱中毒定容通气没有上述风险，但需密切监测气道压力MinVent恒定时的潮气量MechanicalVentilationofCOPD/Asthma|BinDuTuxenDV,LaneS.Theeffectsofventilatorypatternonhyperinflation,airwaypressures,andcirculationinmechanicalventilationofpatientswithsevereair-flowobstruction.AmRevRespirDis1987;136:872-879COPD吸气气流波形MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD吸气气流波形吸气气流波形呼吸机参数恒定气流1正弦波减速气流恒定气流2Vt,ml562±67558±65566±59571±72RR,bpm18.2±1.718.6±1.418.4±1.918.5±1.3MV,lpm10.4±1.610.3±1.510.6±1.610.7±1.8Ti/Ttot0.29±0.040.28±0.030.29±0.040.28±0.03平均吸气流量,lpm38±537±739±738±6MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD吸气气流波形吸气气流波形呼吸力学参数恒定气流1正弦波减速气流恒定气流2PIP,cmH2O47.1±11.547.8±10.839.5±9.746.6±11.0Paw,cmH2O7.6±4.27.2±4.88.4±4.58.4±3.9Pplat,cmH2O20.2±9.119.6±10.618.9±8.821.4±10.4Vd/Vt,%58.4±5.254.5±6.348.6±5.557.6±4.9Cst,ml/cmH2O35.3±8.935.8±11.236.6±9.337.2±9.7MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD吸气气流波形吸气气流波形恒定气流1正弦波减速气流恒定气流2pH7.44±0.047.44±0.077.43±0.067.44±0.04PaO2/FiO2,mmHg236±73231±65223±70227±67PaCO2,mmHg45±1045±1037±946±12A-aDO2,mmHg133.1±36.5136.4±34.2156.3±33.7134.4±35.3HR,bpm106.1±18.1108.3±20.2105.3±18.9109.9±20.5MAP,mmHg92±2388±1888±2190±19MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD吸气气流波形吸气气流波形参数恒定气流1正弦波减速气流恒定气流2WOB,J/L0.92±0.160.88±0.180.75±0.150.92±0.18Raw,cmH2O/L/s12.6±3.112.4±3.611.2±2.412.5±3.3VO2,ml/min384±53389±60377±49382±52VCO2,ml/min274±52280±47273±56276±55症状评分54.5±13.458.6±11.942.7±12.356.1±12.8MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD吸气气流波形MechanicalVentilationofCOPD/Asthma|BinDuYangSC,YangSP.Effectsofinspiratoryflowwaveformsonlungmechanics,gasexchange,andrespiratorymetabolisminCOPDpatientsduringmechanicalventilation.Chest2002;122:2096-2104COPD患者机械通气的最佳吸气气流为减速气流Vt,TI和Pplat相似的情况下，PIP更低正常肺泡过度牵张的风险减小高压报警减少，从而确保潮气量通过选择适宜的吸气气流，有可能改善患者的通气Vt恒定时的呼吸频率MechanicalVentilationofCOPD/Asthma|BinDuTuxenDV,LaneS.Theeffectsofventilatorypatternonhyperinflation,airwaypressures,andcirculationinmechanicalventilationofpatientswithsevereair-flowobstruction.AmRevRespirDis1987;136:872-879延长TE：

Flowvs.

RRVtRRFlowTtotTITEΔTE0.515304.001.003.00–0.515604.000.503.500.500.514304.301.003.300.30MechanicalVentilationofCOPD/Asthma|BinDuVtRRFlowTtotTITEΔTE0.515604.000.503.50–0.5151204.000.253.750.250.514604.300.503.800.30OddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510延长TE的有效方法取决于吸气流量基础值VE≈10lpm且TE>4”时延长TE的作用MechanicalVentilationofCOPD/Asthma|BinDuLeathermanJW,McArthurC,ShapiroRS.Effectofprolongationofexpiratorytimeondynamichyperinflationinmechanicallyventilatedpatientswithsevereasthma.CritCareMed2004;32:1542-1545COPD机械通气：外源性PEEP6名重度气道梗阻患者PEEP5–15cmH2OVEI,FRC,Pplat相应升高Peso,CVP升高，CO和MAP降低MechanicalVentilationofCOPD/Asthma|BinDuTuxenDV.Detrimentaleffectsofpositiveend-expiratorypressureduringcontrolledmechanicalventilationofpatientswithsevereairflowobstruction.AmRevRespirDis1989;140:5-9COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuCaramezMP,BorgesJB,TucciMR,etal.Paradoxicalresponsestopositiveend-expiratorypressureinpatientswithairwayobstructionduringcontrolledventilationCritCareMed2005;33:1519-1528对于部分气道梗阻的患者而言,应用控制通气过程中,设置外源性PEEP能够缓解过度充盈基础疾病,机械力学指标或呼吸机设置均无法预测上述结果逐渐增加PEEP并观察平台压力改变,是减少副作用的合理方法COPD机械通气：外源性PEEPMechanicalVentilationofCOPD/Asthma|BinDuGuerinC,Milic-EmiliJ,FournierG:EffectofPEEPonworkofbreathinginmechanicallyventilatedCOPDpatients.IntensiveCareMed2000；26:1207-1214.对于COPD患者>40%的吸气肌力用于克服autoPEEP外源性PEEP能够减少触发吸气所需的吸气肌力，并改善人机协调性COPD机械通气：外源性PEEPAECOPD控制通气过程中不宜应用外源性PEEP一旦自主呼吸恢复，应使用低水平PEEP保证患者舒适不超过autoPEEP降低触发功MechanicalVentilationofCOPD/Asthma|BinDuAECOPD/哮喘机械通气初始设置呼吸参数设置模式VCV分钟通气量<10lpm潮气量6–10ml/kgPBW呼吸频率10–14bpm平台压<30cmH2O吸气流量60–80lpm吸气流量波形减速气流呼气时间4–5sPEEP0cmH2OFIO2SaO2>90%MechanicalVentilationofCOPD/Asthma|BinDuOddoM,FeihlF,SchallerM,etal.Managementofmechanicalventilationinacutesevereasthma:practicalaspects.IntensiveCareMed2006;32:501-510COPD自主呼吸时呼气触发灵敏度MechanicalVentilationofCOPD/Asthma|BinDuTassauxD,GainnierM,BattistiA,etal.Impactofexpiratorytriggersettingondelayedcyclingandinspiratorymuscleworkload.AmJRespirCritCareMed2005;172:1283-1289COPD自主呼吸时呼气触发灵敏度MechanicalVentilationofCOPD/Asthma|BinDuTassauxD,GainnierM,BattistiA,etal.Impactofexpiratorytriggersettingondelayedcyclingandinspiratorymuscleworkload.AmJRespirCritCareMed20