急性肺损伤（ALI）

null第二十二章 急性肺损伤（ALI） 急性呼吸窘迫综合征（ARDS） ACUTE LUNG INJURY ACUTE RESPIRATORY DISTRESS SYNDROME 第二十二章 急性肺损伤（ALI） 急性呼吸窘迫综合征（ARDS） ACUTE LUNG INJURY ACUTE RESPIRATORY DISTRESS SYNDROME 徐州医学院麻醉学系危重病医学教研室　孟雷概述概述DAD: diffuse alveolar damage（弥漫性肺泡损害） 　Etiology: shock, infection, trauma, aspiration, drugs, inhalation etc. ALI & ARDS: a syndrome of pulmonary vasoconstriction, inflammation and greater permeability of both the alveolar capillary endothelium and epithelium that results in both arterial hypoxemia, resistant to oxygen therapy and the appearance of diffuse infiltrates on chest X-rays.Synonyms for Acute(adult) Respiratory Distress SyndromeSynonyms for Acute(adult) Respiratory Distress SyndromeAdult hyaline membrane disease Adult respiratory insufficiency syndrome Congestive atelectasis Da Nang lung Hemorrhagic atelectasis Hemorrhagic lung syndrome Hypoxic hyperventilation Postperfusion lung Post-traumatic atelectasis Post-traumatic pulmonary insufficiency Progressive pulmonary consolidation Progressive respiratory distress Pump lung、Shock lung Transplant lung Traumatic wet lung、Wet lung、White lungFrom Taylor RW, Duncan CA: The adult respiratory distress syndrome. Resident Med 1983;1:17ALI & ARDSALI & ARDS 病理生理改变： 　急性肺损伤反应，肺泡的弥漫性损害（血管内皮和肺泡上皮细胞的损伤，肺泡的实变，成纤维细胞的增生和胶原纤维的沉着）。ALI & ARDSALI & ARDSCLINICAL　FEATURES（临床表现） 呼吸急促，呼吸音改变 进行性呼吸困难，低氧血症 双侧肺部浸润影 心动过速等ALI & ARDSALI & ARDSViolent and choatic immunologic reactionPulmonary microvascular thrombosis Aggregation of inflammatory cells Stagnation of blood flow through the lungs Intensive hypoxemia Pulmonary arterial hypertension Radiographic evidence: pulmonary edemaStiff lung ALI & ARDSALI & ARDSARDS is not a single disease, but rather a pathophysiologic syndrom.§1. 病因 etiology§1. 病因 etiologySepsis & MODS Trauma Aspiration(误吸) Blood transfusion etc.§2. 病理生理 pathophysiology§2. 病理生理 pathophysiology基本病理改变： acute exudative phase proliferative phase chronic fibrotic phase PATHOPHYSIOLOGYPATHOPHYSIOLOGY非心源性高通透性肺水肿 　Non-cardiac pulmonary edema with increased permeability 肺呼吸功能改变 　Changes of lung respiratory function 肺循环功能改变 　Changes of lung circulatory function PATHOPHYSIOLOGYPATHOPHYSIOLOGYInflammatory ResponseInflammatory ResponseAcute alveolar and endothelial damageVascular permeabilityLung waterproteinGas exchangeincreasedecreaseInflammatory Mediators in ARDSInflammatory Mediators in ARDSCytokines Interleukins Tumor necrosis factor Interforns Complement proteins Contact activation proteins Bradykinin Coagulation proteins Thrombin Fibrin degradation products Progtaglandins Leukotrienes Vasoactive peptides Serotonin Histamine Platelet-activating factorsFrom Foner BJ, Norwood S, Taylor RW: The acute repiratory distress syndrome In: Critical Care. 3rd ed. Civetta JM, Taylor RW, Kirby RR(Eds). Philadelphia, Lippincott-Raven, 1997, pp 1825～1839PATHOPHYSIOLOGYPATHOPHYSIOLOGYPulmonary edema formation and microcirculatory injury:Pulmoanry edema formation Endothelial injury Epithelial injury Ventilator induced pulmoary edemaPATHOPHYSIOLOGYPATHOPHYSIOLOGYHistologic changes Surfactant Alteration Lung mechanics and Gas exchange Extrapulmonary organ failureComponents and Individual Values of the Lung Injury ScoreComponents and Individual Values of the Lung Injury ScoreComponent Value Chest roentgenogram score No alveolar consolidation 0 Alveolar consolidation confined to 1 quadrant 1 Alveolar consolidation confined to 2 quadrant 2 Alveolar consolidation confined to 3 quadrant 3 Alveolar consolidation in all 4 quadrant 4 Hypoxemia score PaO2/FiO2 ＞300 0 PaO2/FiO2 225～299 1 PaO2/FiO2 175～224 2 PaO2/FiO2 100～174 3 PaO2/FiO2 ＜100 4 PEEP score PEEP ≤5 cmH2O 0 PEEP 6～8 cmH2O 1 PEEP 9～11 cmH2O 2 PEEP 12～14 cmH2O 3 PEEP ≥15 cmH2O 4The final value is obtained by dividing the aggregate sum by the number of components that were used. No lung injury: 0 Mild to moderate: 0.1～2.5 Severe: ＞2.5From Murray JF, Mathay MA, Luce JM, et al: An expanded definition of the adult respiratory distress syndrome. Am Rev Respir Dis 1988;138:720.临床分期临床分期ARDS分期： 第一期：原发病临床表现 第二期：轻度呼吸困难 第三期：呼吸窘迫 第四期：严重呼吸窘迫§4. Diagnosis Criteria§4. Diagnosis CriteriaALI: PaO2/FiO2≤300 (whatever PEEP) 　 Bilateral infiltrates on chest radiograph PAWP≤18mmHg or no clinical findings suggestive of increased LAP ARDS: PaO2/FiO2≤200 (whatever PEEP) Bilateral infiltrates on chest radiograph PAWP≤18mmHg or no clinical findings suggestive of increased LAP From Bernard GR, Artigas A, Brigham KL, et al: The American-European consensus conference on ARDS definitions. Am J Respir Crit Care Med 1994;149:818null患者，女性，63，误吸。38mmHg, 100% 9h后： 56mmHg, 50% 13h后： 65mmHg, 50% 20h后： 79mmHg, 50% 34h后： 73mmHg, 50%§5. 治疗 therapy or treatment§5. 治疗 therapy or treatment积极治疗原发疾病　　　7. 部分液体通气 控制感染　　　　　　　8. 表面活性物质替代 机械通气支持　　　　　9. 免疫疗法的应用 降低肺血管阻力　　　 10. 营养代谢支持疗法　 肾上腺糖皮质激素　　 12. 循环功能的支持 体外膜肺氧合 Fluid TherapyFluid TherapyConventional Approach: Aims of resuscitation in ARDS: Attain normal vital signs while PAWPis kept as low as possible. Fluid restriction and diuretic administration. (1)Input and output records of large amount of fluids given befor the diagnosis of ARDS was given. (2)Clinical evidence of excessive fluid retention, such as peripheral edema. (3)Clinical radiologic evidence of pulmoary congestive and edema (4)Improvement in arterial blood gas values after diuretic therapyFluid TherapyFluid TherapyCritique of conventional approach: Pulmonary edema may be caused by so many diseases. In postoperative, posttrauma and sepsis patients, pulmonary edema is due to overexpansion of the interstitium, not to plasma volume overload. Peripheral and pulmonary edema reflect: interstitial fluid volumes increase, plasma oncotic pressure decrease, nutritional failure, endothelial permeability increase, lung hypoxia or anaphylactoid reactions(过敏反应) Hypovolumia is a major pathophysiologic factor of ARDS; pulmonary edema is an effect, not the cause of, ARDS. Fluid TherapyFluid TherapyFluid therapeutic goals values: CI＞4.5 L/min.m2 DO2＞ 600 ml/min.m2 VO2＞ 170ml/min.m2 Blood volume 500 ml greater than normal 3.2 L/min.m2 (men) 2.7 L/min.m2 (women) All these values should be reached within 8～12h postoperatively or after trauma From Shoemaker WC, Ayres SM, Ake Grenvik, Holbrook PR. Textbook of Critical Care, 4th Edition. Harcourt Publishers Limited. 2000. 1397.Fluid TherapyFluid TherapyFor patients with severe lung injury, less is more. —in a news release from the National Heart, Lung and Blood Institute with this headline. Fluid management is a complex issue, and, until now, it was not clear whether providing more or less fluids was more beneficial. Current trends in usual care appear to more closely resemble the liberal fluid management arm of this study-the stdy arm with worse outcomes. —Gordon Bemard, chair of NIH ARDS Network Steering Committee Mechanical VentilationMechanical VentilationLung-protective strategies(肺保护策略): Permissive hypercapnia(允许性高碳酸血症) Low tidal volume + high PEEP Recruitment maneuver(肺复张法) Prone position(俯卧位) NO inhalation Extracorporeal gas exchange(体外气体交换) ECMO(体外膜肺氧合) ECCO2OR(体外CO2清除) Lung protective ventilationLung protective ventilationLow tidal volume: 6 ml/kg vs 10～12 ml/kg Peak airway pressure ≤30 cmH2O Driving pressure ≤20 cmH2O PaCO2 ≤60 mmHg pH ≥7.20 High PEEP than conventional valuesLung protective ventilation --physiologic consequencies of hypercapniaLung protective ventilation --physiologic consequencies of hypercapniaCellular effects: intracellular acidosis In the absence of hypoxemia, intracellular acidosis appears to be well tolerated in critical ill patients. Cardiovascular effects: high sympathetic activity Increase: HR, BP, PVR Decrease: SVR CNS effects: CBF and ICP increase Consciousness: severe agitation, seizure, coma. Lung protective ventilation --recruitment maneuverLung protective ventilation --recruitment maneuverOpen the lung and keep the lung openLung protective ventilation --stepwise recruitment maneuverLung protective ventilation --stepwise recruitment maneuverPEEP titration depend on: Pdeflex 、PaCO2 、Compliance PEEP in crement: 2～3 cmH2O Maintain: 1～2 minutes PEEP target:　16/1st RM; 20/2nd RM; 26-30/3rd RM PIPmax: 40 cmH2O Interval: twice a day Prone position 俯卧位Prone position 俯卧位Physiologic effects: Reexpand consolidated depedent lung region Improve V/Q matching Reduce the compressive force of the heart to lung Complications: Accidental extubation, removal of invasive catheters, facial injury, retinal ischemia, blindness from pressure on the eyeball, peripheral neuropathy,etc.再　见再　见