病理生理基础

1、病理生理基础Ventilation in ALIBackgroundpALIALI是是ICUICU常见的危重病常见的危重病p病理生理特点病理生理特点 肺容积明显降低肺容积明显降低 肺顺应性明显下降肺顺应性明显下降 通气通气/ /血流比例失调血流比例失调p肺组织分布肺组织分布“不均一不均一”TIDAL recruitment end-expiration end-inspirationTIDAL hyperinflation end-expiration end-inspirationbackgroundIntensive Care Med,2005, 31:776784非重力依赖区过度膨胀非重

2、力依赖区过度膨胀重力依赖区潮汐性塌陷复张重力依赖区潮汐性塌陷复张Best Practice & Research Clinical Anaesthesiology 2010;24:171-182.VILI立项依据Always opening and closingVILITidal collapseVT0 10 20 30 400 10 20 30 40 50%Paw(cmH2O)Closing pressureOpening pressureCrotti,et al Am J Respir Crit Care Med 2001;164:131-140HEARTSPPEEP-Keep

3、the lung openLow VtRM Open lung BackgroundARDS病理生理变化病理生理变化肺保护性通气肺保护性通气机械通气患者病死率仍机械通气患者病死率仍高达高达37%Intensive Care Med 2009;35:816825.13,322 pats admitted to 299 ICUs from 35 countriesBackground6mlKg小潮气量小潮气量非重力依赖区肺泡依然过度膨胀非重力依赖区肺泡依然过度膨胀 Background中大医院重症医学科预试验中大医院重症医学科预试验重力依赖区通气不良和塌陷肺泡重力依赖区通气不良和塌陷肺泡明显增加明

4、显增加 Background中大医院重症医学科预试验中大医院重症医学科预试验HEARTSPAt present：Lung Protective Ventilation Strategies非重力依赖区非重力依赖区肺泡过度膨胀肺泡过度膨胀 重力依赖区重力依赖区肺泡潮汐性塌陷复张肺泡潮汐性塌陷复张 BackgroundVILIVILI几乎无处不在几乎无处不在潮气量和潮气量和PEEPPEEP的设定依然矛盾重重的设定依然矛盾重重潮气量设置困难个体化难！潮气量设置困难个体化难！重症重症ARDS大量肺泡塌陷大量肺泡塌陷即使即使“小小”潮气量仍然导致潮气量仍然导致VILI潮气量应更小潮气量应更小VILI塌陷

5、肺泡少塌陷肺泡少“小小”潮气量太小，肺泡通气无法保证，导致肺泡塌陷潮气量太小，肺泡通气无法保证，导致肺泡塌陷显然，显然，6mlKg的的“小小”潮气量不适合所有潮气量不适合所有ARDSThe most controversial issue in ALI/ARDS pts PEEP水平不足水平不足肺泡反复塌陷、复张，产生剪切力肺泡反复塌陷、复张，产生剪切力 VILIPEEP水平过高水平过高肺泡过度膨胀，导致气压伤肺泡过度膨胀，导致气压伤 VILIMethods to titrate PEEP in ALI/ARDS Best PEEP(Suter, NEJM, 1975) Super PEEP(

6、Kirby, Chest, 1975) Pflex(Amato, Am J Respir Crit Care Med, 1995) Oxygenation scale(ARDSnet, NEJM, 2000) Stress index(Ranieri, Anesthesiology, 2000) Pmc(Goddon, Anesthesiology, 2001) FRC+Cst(Lambermont, Critical Care, 2008) Pes(Talmor, NEJM, 2008) Increased recruitment strategy(Mercat, JAMA, 2008) E

7、IT(Meier, ICM, 2008) Which one is best?滴定PEEP的最佳方法 简便、床边 快速 安全 可重复，为PEEP滴定提供可靠信息Stress index-Stress index-肺牵张指数肺牵张指数容量控制通气、恒定流速容量控制通气、恒定流速Stress index-Stress index-肺牵张指数肺牵张指数P-tP-t曲线吸气支：曲线回归方程曲线吸气支：曲线回归方程P=a P=a * * t tb b + c+ c b b 值：肺牵张指数值：肺牵张指数描述曲线的形状，反映肺泡开放与塌陷程度的力学指标描述曲线的形状，反映肺泡开放与塌陷程度的力学指标Slut

8、sky AS, Aneathiology, 2000,93: 1320-8 Grasso S, Crit Care Med, 2004, 32: 101827Ranieri VM et al Anesthesiology 2000Stress index-Stress index-肺牵张指数肺牵张指数stress index= 1 before RMstress index = 1 after RM 0.6 stress index 0.8 0.8 stress index 11.1 stress index 1.31.3 stress index 1.5End InspirationEnd

9、Expirationb b值与塌陷和过度膨胀值与塌陷和过度膨胀b b值与塌陷和过度膨胀值与塌陷和过度膨胀肺牵张指数指导肺牵张指数指导ARDSARDS患者患者PEEPPEEP的选择的选择 14例ARDS患者实施肺复张后容量控制通气 用回归法求得方程: P=a*tb+c. b为肺牵张指数。 复张后调整PEEP使 b1(0.6b0.8) b=1(0.9b1(1.1b1.3)0100200300400500600700复张前 b1PaO2/FiO2复张容积 与复张前比较，*P0.05; 与复张后b1比较，#P0.05; 与b=1比较，P0.05黄英姿，邱海波。中华医学杂志。2009,89:273905

10、1015202530354045复张前 b1PplatCst肺复张后肺复张后b=1b=1时，氧合、顺应性和肺复张容积明显改善时，氧合、顺应性和肺复张容积明显改善与基础状态比较与基础状态比较*P0.05；与氧合法比较；与氧合法比较P0.05；与肺牵张指数法比较与肺牵张指数法比较P0.05；与顺应性法比较；与顺应性法比较P0.05 *不同方法选择最佳PEEP的比较 PEEP(cmH2O)PaO2/FiO2(mmHg)与基础状态比较，与基础状态比较，*P0.05*与基础状态比较，与基础状态比较，*P0.05复张容积复张容积(ml)Cst(ml/cmH2O )THE STRESS INDEX CONC

11、EPT: experimental data0.0 0.5 1.0 1.5 2.0.Ranieri VM et al Anesthesiology 20000.0 0.5 1.0 1.5 2.0.0204060801000204060801001 - Specificity (False Positive Rate) (%)1 - Specificity (False Positive Rate) (%)0 20 40 60 80 1000 20 40 60 80 100total airway injury scoreTNF-IL-6MIP-2THE STRESS INDEX CONCEPT

12、: experimental dataRanieri VM, Slutsky AS Anesthesiology 2000BAL b=1 during SIventilationb=1 during SIventilationP 0.001b1 during NIHventilationb=1 during NIHventilationP 0.0541010IL-1 b=1b=1，炎症反应降低，炎症反应降低B B值滴定值滴定PEEPPEEPB B值反应肺顺应性的动态变化值反应肺顺应性的动态变化 btotal tot = 1.00 but the algorithm is still able to distinguish b1 = 0.91 b2 = 1.11KleisTEK - Advanced Electronic Systems, Ba