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1、Adult Respiratory distress syndrom(ARDS)成人呼吸窘迫综合征,1.Difinition-定义,ALI and its more severe sub-set,ARDS,is a common clinical disorder characterized by injury to the alveolar epithelial and endothelial barriers of the lung,acute inflammation,and protein-rich pulmonary oedema leading to acute respirato
2、ry failure.Often occurs in the setting of MOF.,急性肺损伤及其更加严重的情况ARDS是一种常见的临床异常状况，以肺泡上皮细胞及肺内皮细胞屏障损害、急性炎症反应、富含蛋白的肺水肿导致的急性呼吸衰竭为特点。经常发生于多器管衰竭的情况下。,Diagnostic criteria,Acute onset of respiratory failure with one or more risk factors(table,opposite)HypoxaemiaALI:Ratio PaO2(kPa):FiO2 40ARDS:Ratio PaO2(kPa):Fi
3、O2 27Bilateral infiltrates on CXRPulmonary capillary wedge pressure 19mmHg,with normal colloid oncotic pressure(in patients with hypoalbuminaemia,the critical PCWP is approx.serum albumin(g/l)0.57,see P282)or clinical exclusion of cardiac failure.,诊断标准,发生急性呼吸衰竭，伴有1或多个危险因素（见对侧表）低氧血症 ALI:PaO2(kPa):FiO
4、2 40 FiO2 为吸氧浓度之意 ARDS:PaO2(kPa):FiO2 27胸部X线检查示双肺浸润肺动脉嵌压（PCWP）小于19mmHg，胶体渗透压正常（在低蛋白血症患者，PCWP大约为血清白蛋白(g/l)0.57）或临床排除心力衰竭。,Disorders associated with the development of ARDS,Direct lung injury 直接肺损伤 Aspiration 误吸Gastric contents 胃内容物Near drowning 淹溺Inhalation injury 吸入性损伤Noxious gases 有毒气体Smoke 烟,Disor
5、ders associated with the development of ARDS,Pneumonia 肺炎Any organism 任何病原菌PCP（Pneumocystis pneumonia）卡氏肺囊虫性肺炎Pulmonary vasculitides 肺血管炎Pulmonary contusion 肺挫伤Drug toxicity or overdose 药物中毒或过量Oxygen 氧中毒Opiate overdose 阿片剂过量Bleomycin 博来霉素Salicylates 水杨酸盐,Indirect(non-pulmonary)injury,Shock 休克 Septic
6、aemia 脓毒血症Amniotic or fat embolism 羊水或脂肪栓塞Acute pancreatitis 急性胰腺炎Massive haemorrhage 大出血Multiple transfusions 大量输血DIC（diffusion intravascular coagulation）,Indirect(non-pulmonary)injury,Massive burns 大面积烧伤Major trauma 严重创伤Head injury 头外伤Raised ICP 颅内压升高Intracranial bleed 颅内出血Cardio-pulmonary bypass
7、心肺旁路术Acute liver failure 急性肝衰减,Investigations,CXRABG(consider arterial line as regular samples may be required)Take blood for FBC,U&Es,LFTs and albumin,coagulation,X-match,and CRPSeptic screen(culture blood,urine,sputum)ECGConsider drug screen,amylase if history suggestivePulmonary artery catheter t
8、o measure PCWP,cardiac output,mixed venous oxygen saturation and to allow calculation of haemodynamic parameters,检查,胸部X线检查动脉血气分析采血查全血细胞、肾功、电解质、肝功和白蛋白、凝血功能、X-match和 CRP感染筛查（血、尿、痰培养）心电图如有相关病史行药物筛查及淀粉酶检测肺动脉导管测量PCWP，心输出、混合静脉氧浓度并计算血流动力学参数。,Other investigations if appropriate其它可用检查,CT chestBroncho-alveola
9、r lavage for microbiology and cell count(?eosinophils)Carboxy-haemoglobin estimation.胸部CT检查支气管-肺泡灌洗查微生物及细胞计数（嗜酸性粒细胞？）碳-氧血红蛋白测定,Management,Almost all cases of ALI alone will require HDU/ICU care:liaise earlyThe main aim is to identify and treat the underlying cause whilst providing support for organ
10、failure:Respiratory support to improve gas exchange and correct hypoxiaCardiovascular support to optimize oxygen delivery to tissuesReverse or treat the underlying cause.,治疗,几乎所有的ALI患者需要重症监护主要目的是明确诊断，治疗原发病并对衰竭器管提供支持。呼吸支持以改善通气、纠正缺氧。心血管系统支持以改善组织供氧 逆转和治疗原发病,Respiratory support-Spontaneously breathing p
11、atient,In very mild ALI,hypoxia can be corrected with increased inspired oxygen concentrations(FiO2 40-60%).However,such patients are rarely recognized as having ALI as a cause of their respiratory failure.对于非常轻症的ALI患者,增加吸入氧浓度(FiO2 40-60%)即可纠正缺氧。然而，这样的轻症患者很少被诊断出ALI作为其呼吸衰竭的原因。,自主呼吸患者的呼吸支持,Patients in
12、variably require higher oxygen concentrations(non-rebreather masks with reservoir FiO2 60-80%)or CPAP(see P904).Consider transfer to HDU/ICU如果患者总是需要高浓度给氧（带贮气器的非再呼吸面罩，给氧浓度60%80%）或持续正压通气支持，考虑转入ICU。,Mechanical ventilation,Indications for mechanical ventilationInadequate oxygenation(PaO2 0.6)Rising or e
13、levated PaCO2(6kPa)Clinical signs of incipient respiratory/cardiovascular failure.机械通气适应症.氧合不足（当 FiO2 0.6时PaO2 45mmHg)临床出现呼吸或循环衰竭,Mechanical ventilation,This is the realm of the ICU physician.Main aim is to improve oxygenation/ventilation while minimizing the risk of further ventilator-induced lung
14、injury;termed lung protective ventilation.机械通气属于ICU医师的工作范围。主要目的是改善氧合/通气同时最小化通气诱发的肺损伤，也就是肺保护性通气策略。,Mechanical ventilation-General principles（一般原则）,Controlled mechanical ventilation with sedation(neuromuscular blockade).用镇静剂(神经肌肉阻滞剂)实现可控机械通气Aim for tidal volume 6ml/kg.Recent evidence has confirmed tha
15、t ventilation with smaller tidal volumes is associated with improved outcome compared to the traditional approach(10-12ml/kg).目标潮气量6ml/kg。最近的证据表明小潮气量通气与传统的方法（10-12ml/kg）比可明显改善愈后。,Mechanical ventilation-General principles,Start with FiO2=1.0.Subsequent adjustments are made to achieve oxygen saturatio
16、n 90%with FiO2 0.6.开始用纯氧，继而调整使得在给氧浓度小于0.6时氧饱和度达到90%以上。Positive end expiratory pressure(PEEP)improves oxygenation in most patients and allows reduction in FiO2.Usual starting level,5-10cm H2O,with optimal levels in the range 10-15cm H2O.Beware hypotension due to reduction in venous return.在大多数患者，PEEP
17、可以改善氧合从而可降低给氧浓度。通常从5-10cm H2O开始，理想水平为10-15cm H2O。需小心因静脉回流减少而导致的低血压。,Mechanical ventilation-General principles,The use of smaller tidal volumes may impair CO2 clearance with resulting acidosis despite high ventilatory rates(20-25 breaths/minute).Further increases in rate or tidal volume risk worsenin
18、g ventilator-induced lung injury.Gradual increases in pCO2(up to 13kPa)are well tolerated in most patients and acidosis(pH 7.25)can be treated with intravenous bicarbonate,so-called permissive hypercapnia.尽管通气频率高（20-25次/分），应用小潮气量通气模式可能降低CO2清除率导致酸中毒。进一步增加呼吸频率或潮气量则增加通气诱发的肺损伤的风险。大多患者可以耐受缓慢增加的pCO2（最高可达1
19、3kPa/97.7mmHg，酸中毒时(pH 7.25)可以用静滴碳酸氢盐纠正，所谓允许性高碳酸血症.,Mechanical ventilation-General principles,If oxygenation/ventilation cannot be improved despite these measures,the following can be considered;Inverse ratio ventilation(P906):may improve oxygenation,but pCO2 may rise furtherProne positioning:improve
20、s oxygenation in 70%of patients with ARDSInhaled vasodilators(nitric oxide,nebulized prostacyclin):may improve oxygenationHigh-frequency ventilation:only available in specialist centers.,如果以上措施还不能改善氧合/通气，可以考虑以下措施。反比通气可以改善氧合，但可能导致pCO2 进一步升高。前倾位通气，可以改善70%的ARDS患者的氧合 吸入血管扩张剂可以改善氧合：一氧化氮，雾化吸入前列腺素高频通气：仅在专科
21、中心使用。,Cardiovascular support心血管支持,Arterial line essential for continuous blood pressure measurements.Other invasive monitoring is invariably used(PA catheter,PiCCO,oesophageal Doppler),but their individual roles and effects on outcome are unclear.动脉置管持续血压监测是必要的。其它侵入性监测也总是在使用，如肺动脉导管，PICCO，食管多普勒。但这些监测
22、系统的作用的对愈后的效果尚不清楚。,Cardiovascular support,Most patients are haemodynamically compromised due to the underlying condition and/or ventilatory management,and benefit from fluid resuscitation.This may risk worsening capillary leak in the lung and compromise oxygenation/ventilation.Aim for a low-normal in
23、travascular volume whilst maintaining cardiac index and mean arterial pressure.大多数患者因潜在疾病和/或机械通气治疗损害了血流动力学，液体复苏有利于改善这种状况，但可能有加重肺毛细胞血管渗出的风险，从而损害氧合/通气功能。因此，支持的目的在于维持一个低-正常的血管内容量，同时又可保持心输出指数及平均动脉压。,Cardiovascular support,Inotrope and/or vasopressor support is commonly required and the choice of agent i
24、s usually decided on a combination of clinical evaluation and invasive haemodynamic monitoring(cardiac index,oxygen delivery,mixed venous/central venous saturation,lactate).Agents commonly employed include dobutamine,dopamine,epinephrine,norepinepherine.Repeated assessment is essential.,通常需要正性肌力药和血管
25、活性药物支持，药物的选择需综合临床状况评估和侵入性血流动力学监测指标（心指数、氧输送、混合静脉/中心静脉氧饱和度、乳酸盐浓度等）。常用药物包括：多巴酚丁胺、多巴胺、肾上腺素、去甲肾上腺素。,On-going management,Look for and treat a precipitant(see table,P231)寻找并治疗诱因。SepsisFever,neutrophilia,and raised inflammatory markers are common in ALI/ARDS and do not always imply sepsisA trial of empiric
26、antibiotics guided by possible pathogens,and following an appropriate septic screen(consider bronchoalveolar lavage once intubated and stable),should be considered.Antibiotics should be modified or discontinued in light of microbiological resultsIndwelling CVP catheters are a common source of sepsis
27、Consider low-dose steroid infusion if(see below)Consider activated protein C,which has been shown to improve survival in patients with septic shock with multi-organ failure.,脓毒症发热、中性粒细胞增多、炎症标志物升高等为ALI/ARDS患者的通常表现，但并不总意味着存在脓毒症应考虑行合理的病原菌筛查（一旦插管，病情稳定后可考虑行支气管肺泡灌洗）并根椐可能病原菌的经验性试验性治疗。抗生素应根据病原菌筛查结果调整或终止。留置的
28、中心静脉导管是脓毒症一常见病源。考虑输注低剂量类固醇（见下文）考虑使用活化蛋白C，已表明该药可以改善有多脏器衰竭的脓毒症性休克的生存率。,On-going management,Renal failure.Common and may require renal replacement therapy to control fluid balance and blood biochemistry.Enteral feeding.Helps maintain integrity of the gut mucosa and is associated with a lower risk of sy
29、stemic sepsis when compared to parenteral feeding(TPN).Delayed gastric emptying and reduced gut motility is common in ICU patients and may respond to pro-kinetic drugs(metoclopramide,erythromycin)or may require nasojejunal feeding.Stress ulcer prophylaxis(H2-blockers)should be considered if mechanic
30、al ventilation 48 hours,or multi-organ failure.,治疗肾衰：肾衰常见，可能需要肾脏替代治疗以控制液体平衡和血生化。经肠道饮食:有助于保持消化道内膜的完整性，与全胃肠外营养比较落，可以减少全身脓毒症的风险。胃排空延迟、肠蠕动减弱在ICU患者中常见，对促胃肠动力药物（胃复安、红霉素）有反应，或需要经鼻导管空肠饮食。如果机械通气超过48小时或有多脏器衰竭，应考虑应激性溃疡的预防（H2-blockers）,On-going management,Coagulopathy.Common and if mild does not require therapy
31、.If severe/DIC,expert advice should be sought.凝血障碍：常见，如果轻微则不需治疗。如出现严重凝血障碍如DIC，则需寻求专家的指导。Steroid therapy 激素治疗ALI/ARDS:no benefit in the acute stage.Treatment(2mg/kg/day of methylprednisolone)later in the course of the disease(7-10 days)may improve prognosis but further studies are awaited.ALI/ARDS：在急
32、性期使用无益处。在疾病晚期（7-10天）治疗可以改善预后，但需待进一步的研究结果。,On-going management,Sepsis:evidence suggests that some patients with refractory septic shock(ongoing/increasing vasopressor requirements)may have relative or functional adrenal insufficiency and may benefit from supraphysiological steroid replacement(200-300
33、mg/day hydrocortisone).Identification of patients likely to benefit unclear at present,but ACTH stimulation test may help discriminate.脓毒症：证据表明，一些难治性脓毒症性休克（正在使用或需增加血管活性药物用量）患者有相对的功能性肾上腺功能不全，可能从超生理剂量的激素（200-300mg氢化可的松）替代治疗获益。目前如何识别这些可能获得益的患者尚不清楚，但ACTH刺激试验可能有助于区分他们。,Causes of sudden deterioration in A
34、RDSARDS患者病情突然恶化的原因,Respiratory 呼吸系统Pneumothorax 气胸Bronchial plugging 支气管堵塞Displaced ET tube 气管内导管移位Pleural effusion(haemothorax)胸膜渗出（血胸）Aspiration(e.g.NG feed)误吸（如经鼻-胃管饮食）Cardiovascular 心血管系统Arrhythmia 心律失常Cardiac tamponade 心包添塞Myocardial infarction 心肌梗死GI bleed(stress ulcer)消化道出血（应激性溃疡）Septicaemia
35、脓毒血症,Outcome-愈后,The outcome for ALI/ARDS has improved in recent years,with overall mortality rates of 40%.近年来，ALI/ARDS的愈后已大大改善，总死亡率40%。Patients with ALI/ARDS and sepsis,liver disease,non-pulmonary organ dysfunction,or advanced age have higher mortality rates.对于有脓毒症的ALI/ARDS患者合并肝脏疾病、非肺器管功能不全、高龄等死亡率较高
36、。,In survivors,although formal lung function tests are abnormal,respiratory compromise at 1-2 years is unusual.在存活患者，尽管正规的肺功能检测异常，但呼吸功能损害在1-2年内是罕见的。There is increasing evidence that survivors suffer considerable neuromuscular and psychological disability.This may reflect the period of prolonged critical illness rather than be specific for ALI/ARDS.越来越多的证据表明，存活者存在相当严重的神经肌肉残疾和心理障碍。这可能是长期严重疾病的结果，而不是因为ALI/ARDS有什么特殊。,
