医学精品课件ARDS呼吸功能监测与通气策略抉择

1、ARDS呼吸功能监测与通气策略抉择 邱海波 刘玲东南大学附属中大医院ICU2021/7/15 星期四1内容提要 Physiopathologic course of ARDS and the dilemma in Mechanical ventilationOxygenation and ShuntRespiratory mechanicsCompliance (Elastance) and ResistanceStress indexEsophageal PressureVd / Vt2021/7/15 星期四2Therapeutic target of MV in ARDSBecome e

2、vident over the past two decadesMV itself can augment or cause pulmonary damageShift of therapeutic target of MV in ARDS 1970sNormal gas exchange1980-1990Protection of thelung from VILIN Engl J Med 1972;287:799-806.Lancet 1980;2:292-4.Am Rev Respir Dis 1987; 135:312-5.Intensive Care Med 1990;16:372-

3、7.2021/7/15 星期四3The lung-protection strategyLung recruitment-open the lung Use of higher PEEP-keep lung open (avoid collapse/recruitment) Low tidal volumes (Pplat 30cmH2O)- avoid overdistension Prevent regional and global stress and strain on the lung parenchymaAm J Respir Crit Care Med. 2008, 178:

4、346355.2021/7/15 星期四4Same MV strategy sutiable for every ARDS pat ?May be No.Physiological effects of RM and PEEP associated with patients individual characteristics Inflamattion spreading from core diseasePercentage of potentially recruitable lungDifferent stages of ARDSN Engl J Med. 2006, 354; 177

5、5-86 .JAMA. 1994, 271, 1772-79. 2021/7/15 星期四5Inflamattion spreading from core diseasePossible modelLowerHigherHigher severity mortalityCore disease 24%Inflammation spreading 1Lower severity mortality2021/7/15 星期四6Potentially recruitable lungLower percentage of potentially recruitable lungHigher per

6、centage of potentially recruitable lungN Engl J Med. 2006, 354; 1775-862021/7/15 星期四7Mortality in Relation to the Percentage of potentially Recruitable Lung (Panel A) Pulmonary anatomy according to CT Findings in patients with Healthy Lungs, Patients with Unilateral Pneumonia,and Patients with Acute

7、 Lung Injury or ARDS (Panel B).N Engl J Med. 2006, 354; 1775-862021/7/15 星期四8Lower VS Higher percentage of potentially recruitable lungHigher percentage of potentially recruitable lungGreater total lung weights Poorer oxygenation Respiratory-system compliance Higher levels of dead spaceHigher rates

8、of deathN Engl J Med. 2006, 354; 1775-862021/7/15 星期四9Different stages of ARDSPathologic stagesEarly exudative phase edema, bleeding, atelactasis, PMN and plt embolus, and microembolusProliferative phase proliferation of tive II epithelium cellFibrotic phase Proliferation of fibroblastHeterogeneity

9、：location, time courseVersatility : Pathologic changes2021/7/15 星期四10Difficult to assessGattinoni L (1994)Early ARDS (MV up to 1 week): prevalent edemaIntermediate ARDS (between 12 weeks): a transition period during edema begins to be reabsorbed and proliferative processes begin to occurLate ARDS (m

10、ore than 2 weeks): fibrous processesClinical stages of ARDSJAMA. 1994, 271, 1772-79. 2021/7/15 星期四11Early VS Late ARDS 84 sever ARDS for underwent extracoresl support (1979-1992)JAMA. 1994, 271, 1772-79. 2021/7/15 星期四12Early VS Late ARDS JAMA. 1994, 271, 1772-79. 2021/7/15 星期四13CT scan, early VS lat

11、e ARDS Gattinoni L Type 1Early ARDSWeek 1Intermediate ARDSWeek 2Late ARDSWeek 7d)RM: PCV 2min at PIP 50cmH2O/PEEP PUIPAm J Respir Crit Care Med, 2002, 165:1651702021/7/15 星期四16Summary-Early and Late ARDSEarly ARDS is characterized by edema and intact lung structureRecruitability is function of the e

12、xtent of edemaWith time lung structure is altered associated with increased dead space and PCO22021/7/15 星期四17Prognosis of ARDSInflammation spreadingPotentially recruitable lungLowerLower severity mortalityRM and higher PEEP may be harmfulHigherHigher severity mortalityRM and higher PEEP are neededC

13、ore diseaseAggravated Improved Early ARDSLate ARDSEffect of RM and higher PEEP?2021/7/15 星期四18QuestionsHow to know who will get benefit from RM and PEEPHow to set a suitable PEEP in ARDS patientCT scan may be one choiceBut not at bed sidePaO2 (P/F) may be another choiceBut our goal is not better gas

14、 exchangeHow about bedside respiratory mechanical monitoring Reduce VILI2021/7/15 星期四19内容提要 Physiopathologic course of ARDS and the dilemma in Mechanical ventilationOxygenation and ShuntRespiratory mechanicsCompliance (Elastance) and ResistanceStress indexEsophageal PressureVd / Vt2021/7/15 星期四20Shu

15、nt is the fundamental cause of hypoxemia in ARDSRM and PEEPImprove oxygenation(P/F)Reduced Shunt Am J Respir Crit Care Med, 2001, 164:1701-17112021/7/15 星期四21肺泡完全复张的临床标准-P/FPaO2/FiO2400 PaO2 + PaCO2 400 2.PaO2/FiO2 降低5%2021/7/15 星期四22PaO2 + PaCO2 400 (at 100% oxygen): 维持肺开放的可靠指标达到PaO2 + PaCO2 400时：

16、CT显示只有5% 的肺泡塌陷 PaO2 + PaCO2 400对塌陷肺泡的预测： ROC曲线下面积 0.943Borges JB, , Amato MBP.Am J Respir Crit Care Med Vol 174. pp 111, 2006肺泡完全复张的临床标准-CT2021/7/15 星期四23肺泡完全复张的临床标准-CTBorges JB, , Amato MBP.Am J Respir Crit Care Med Vol 174. pp 111, 2006动脉氧合与塌陷肺组织重量明显呈负相关 (R = 0.91)2021/7/15 星期四24Methods of Qs/Qt c

17、alculationQc: 经肺毛细血管回心的血量(已气体交换)Qs: 经短路回心的血量(未经体交换)Qt= Qc+Qs 总回心血量计算公式：太复杂但比较准确正常肺Qs/Qt 4-5%ARDS Qs/Qt常30%2021/7/15 星期四25简化公式吸空气时：吸纯氧时：应用条件吸纯氧10-20min(最大限度纠正相对分流)PaO2150-200mmHg2021/7/15 星期四26P/F and Qs/Qt change with lung recruitment Case 63 Y woman Guillain-Barre Syndrome, Pneumonia, ALIPEEPPEEP20

18、21/7/15 星期四27内容提要Physiopathologic course of ARDS and the dilemma in Mechanical ventilationOxygenation and ShuntRespiratory mechanicsCompliance (Elastance) and ResistanceStress indexEsophageal PressureVd / Vt2021/7/15 星期四28Respiratory mechanics -Compliance (Elastance) and Resistance2021/7/15 星期四29Con

19、cepts and FormulaE=P / VolC= Vol / PCst=Vt / (Pplat-PEEPtot)Cdyn=Vt / (PIP-PEEPtot)R= P / VC= 1 / E2021/7/15 星期四30Compliance and Resistance changes in ARDSCompliance decreased significantlyResistance may increase slightlyCompliance decreasedDue to alveolar collapse Resistance increased2021/7/15 星期四3

20、1Compliance decreasedP-V curve Reduced range of volume excursion: Low complianceFlattening at low and high volumes: Lower and upper inflection pointsVolumePressureNORMALARDS顺应性曲线明显向右下移位2021/7/15 星期四32six pigletsvenous infusion of oleic acidPEEP titration (from 26 to 0 cmH2Owith a Vt of 6 to 7 ml/kg)

21、 performed, following a RMCritical Care 2007, 11: R86.2021/7/15 星期四33Ronitoring respiratory mechanics during a PEEP titration procedure may be a useful adjunct to optimize lung aerationCritical Care 2007, 11: R86.PEEP at min Ers corresponded to the greatest amount of normally aerated areas2021/7/15

22、星期四34%E2: Percentage of volume dependent elastancePercentage of non-linearity of the elastance of the Ers%E230%: tidal overdistensionIntensive Care Med. 2008, 34:22912299In non-injured animals2021/7/15 星期四35Stress index and %E2 are useful in non-injured lungs onlyErs can be superior to the stress in

23、dex and %E2 to guide PEEP titration in focal loss of lung aerationErs seems to be useful for guiding PEEP titration in non-injured and injured lungs2021/7/15 星期四36Female pigsLung lavageCrs: computed using the occlusion techniqueRM: 45 cmH2O for 40 sPeep10 cmH2OPro and Post RM (CT scan)Gas exchange L

24、ung mechanics Amount and the changes in aerated andCritical Care. 2005, 9: R471-R4822021/7/15 星期四37Vpoor: volume of poorly aerated lung; Vhap: volume of hyperinflated lungPmcd: pressure of maximum compliance decrease on inflation curve 2021/7/15 星期四38Crs may be useful for guiding PEEP titrationChang

25、es in aerated and nonaerated lung volumes were adequately represented by Crs Not by changes in oxygenation or shuntCritical Care. 2005, 9: R471-R4822021/7/15 星期四39Case 79 y, man, 75 kg Pneumonia, ARDS, APACH II 27Sedation and nerve block Baiseline: VcV, Vt 500ml, PEEP 6cmH2O, RR 20 b/min, P/F Crs 56

26、, Pplat 16cm H2O, PaCO2 35mmHg, P/F 121RM: SI 40cmH2O30s (P/F400 mm Hg or change1-b=1-b1RM again set the PEEP in b=12021/7/15 星期四47Case64 y, man, 70 kg Multiple trauma, ARDSBaiseline MV set: SIMV+PS (autoflow), Vt 420ml, PEEP10cmH2O, FiO2 50%, RR 20 b/minPplat 26cm H2O, PaCO2 47mmHg, P/F 155Change t

27、o VCV: VT 420ml, RR 20 b/minRM: SI 40cmH2O30s (P/F400 or change1341513161222021/7/15 星期四49Respiratory mechanics -MV Guided by Esophageal Pressure2021/7/15 星期四50MV Guided by Esophageal Pressurein ALIEsophageal pressurepleuralpressure pressureTranspulmonary pressure= pulmonary alveolar pressure -Esoph

28、ageal pressure61 ARDS pats MVControl or esophagealpressureguided groupPrimary end pointimprovement in oxygenationSecondary end points:Respiratory-system compliancePatient outcomesN Engl J Med. 2008, 359; 20952021/7/15 星期四512021/7/15 星期四522021/7/15 星期四532021/7/15 星期四54As compared with the current standard of careSignificantly improves oxygenation and complianceN Engl J Med. 2008, 359; 2095MV Guided by Esophageal Pressure2021/7/15 星期四55内容提要 Physiopathologic course of ARDS and the dilemma in Mechanical ventilationOxygenation and ShuntRespiratory mechanicsCo