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1、1,第十四章 肺功能不全 Chapter 14 Respiratory Failure,2,概 述 General description,肺的正常功能及其评价指标; 呼吸衰竭的概念; 呼吸衰竭的分类。,3,一、肺的正常功能及其评价指标; Respiratory function(External respiration) Non-respiratory functions,概 述 General description,4,呼吸功能的评价指标,肺容量;肺通气功能的评价指标,5,呼吸功能的评价指标,肺弥散量(diffusing capacity): 指气体 在分压差作用下,每分钟经肺泡膜弥散的
2、容量。正常值为:188ml/minkPa。反映肺换气效率。 肺泡气-动脉血氧分压差(PA-aO2):指肺泡 气氧分压与动脉血氧分压之差。PA-aO2=PAO2-PaO2反映肺泡膜氧交换状态。,换气功能的评价指标,6,肺通气、换气功能指标呼衰指数(respiratory failure index,RFI):指动脉血氧分压与吸入气氧浓度之比值。反映外呼吸效率。,呼吸功能的评价指标,7,呼吸动力功能:呼吸的动力功能包括: 气道阻力(Raw) 肺顺应性(CL) 呼吸肌力(Fm)等。 最常用的测定指标是气道阻力(Raw)。,呼吸功能的评价指标,8,Non-respiratory functions,F
3、iltration Defense and immune functionClearance of the foreign bodyin the airwayImmune function Metabolism,9,Generally diagnosed by PaO2 60mmHg(at sea level); When FiO2 20%, then RFI 300 can be used as the index of diagnosis .,二、概念 Concept,External respiratory dysfunction PaO2 60mmHg(at sea level) Wi
4、th or without PaCO2 50mmHg,呼吸衰竭(Respiratory failure),10,呼吸功能不全(Respiratory insufficiency) 外呼吸功能障碍而不能维持血气稳态但未达上述水平;或在静息状态时,血气值正常,仅在运动负荷时PaO2才明显下降或伴PaCO2增高者,称为呼吸功能不全。,二、概念 Concept,11,1. According to whether PaCO2 is normal Type PaO2 (50mmHg),三、呼吸衰竭的分类Classifications,12,2. According to Pathogenesis Ven
5、tilation RF; Exchanging RF. 3. According to Primary Site Central RF; Peripheral RF. 4. According to Duration Acute RF; Chronic RF.,三、呼吸衰竭的分类Classifications,13,1 病因和发病机制 Etiology and Pathogenesis,Pulmonary ventilation disorder,Pulmonary gas exchange dysfunction,14,一、肺通气功能障碍 Pulmonary ventilation diso
6、rder -hypoventilation,限制性通气不足Restrictive hypoventilation 阻塞性通气不足Obstructive hypoventilation,15,(一)限制性通气不足 Restrictive hypoventilation,指呼吸动力减弱或胸廓和肺的扩张性能降低(弹性阻力增大)使肺泡扩张受限引起的通气功能障碍。 During inspiration, the dilation or inflation of alveoli are restricted. It is caused by the diseases that affect the dis
7、tensibility of the alveolar.,16,Paralysis of respiratory muscles,Decreased compliance of chest wall,Causes of restrictive hypoventilation,Decreased compliance of lung,Hydrothorax or pneumothorax,17,由于气道阻塞或狭窄,使气道阻力增加引起的通气障碍。 Obstructive hypoventilation is produced by airway constriction or obstructio
8、n.,(二)阻塞性通气不足 Obstructive hypoventilation,Central airway obstruction,Peripheral airway obstruction,trachea crotch,影响气道阻力的最主要因素是气道内径,18,中央气道阻塞: Central airway obstruction,Extrathoracic airway obstruction,Intrathoracic airway obstruction,Expiration,Expiration,*吸气性呼吸困难 Inspiratory dyspnea,*呼气性呼吸困难Exspi
9、ratory dyspnea,Inspiration,Intra-airway pressure Atmospheric pressure,Inspiration,Intra-airway pressure Intra-thoracic pressure,Intra-airway pressure Intra-thoracic pressure,19,2. 外周气道阻塞 Peripheral airway obstruction,It refers to the airway obstruction at the bronchiole whose diameter is 2mm. Causes
10、 : 慢性支气管炎 chronic bronchitis 支气管哮喘 bronchial asthma 慢性阻塞性肺气肿等 chronic obstructive emphysema ,etc. (主要损害小气道),20,*呼气性呼吸困难,呼气时肺泡缩小,对小气道的牵拉作用减弱,胸内负压减小,气道内径变小,阻力增大,小气道狭窄更加明显; 吸气时反之,小气道狭窄减轻。,21,肺气肿病人肺弹性回缩力降低,等压点也向肺泡端移动(上移),易致小气道受压而闭合.,22,(三)全肺通气不足时的血气变化 Blood gas changes in hypoventilation,23,二、肺换气功能障碍 Pu
11、lmonary gas exchange dysfunction,弥散障碍 (Diffusion disorder) 肺泡通气与血流比例失调(Ventilation/perfusion imbalance) 解剖分流增加 (Increase of anatomic shunt),24,(一) 弥散障碍 Diffusion disorder,1. 概念 Concept 弥散障碍是指由肺泡膜面积减小或肺泡膜异常增厚和弥散时间缩短引起的气体交换障碍。,25,2. 弥散障碍的常见原因 Common causes of diffusion disorder,Area of alveolar-capill
12、ary membrane ,Normal adult R-M: 80 m2 At rest, used R-M: 3540 m2 Causes: 肺不张(atelectasis) 肺实变(pulmonary consolidation) 肺叶切除(lobar resection) 肺气肿(emphysema),26,Area of alveolar-capillary membrane Thickness of the membrane ,2. 弥散障碍的常见原因 Common causes of diffusion disorder,27,Area of alveolar-capillary
13、 membrane Thickness of the membrane Shortening of the diffusion time体力负荷增加(劳动、运动),2. 弥散障碍的常见原因 Common causes of diffusion disorder,28,At rest-no changes. Only when the pulmonary blood stream speeds up-PaO2 , PaCO2 normal or .,3.弥散障碍时的血气变化 Blood Gas Changes in Diffusion Disorder,Type RF,29,(二)肺泡通气与血流
14、比例失调Ventilation-perfusion imbalance,30,Normal ventilation and blood flow distribution in lung,more marked,31,肺部疾病时,通气与血流比例严重失调,患者不能进行有效的换气。这是肺部疾病引起呼吸衰竭最常见的机制。 Ventilation/perfusion imbalance consists of 部分肺泡通气不足(功能性分流) Partial alveolar hypoventilation(Functional shunt / Venous admixture) 部分肺泡血流不足(死腔
15、样通气)Partial alveolar hypoperfusion(Dead space like ventilation),32,部分肺泡通气不足 Partial alveolar hypoventilation (VA/Q),支哮、慢支、阻塞性肺气肿,部分肺泡 阻塞性通气不足,肺纤维化、肺水肿、肺不张等,部分肺泡 限制性通气不足,33,部分肺泡通气 血流正常,V/Q,静脉血掺杂 (功能性分流),3%30-50%,病肺:PaO2 、CaO2 ,健肺:PaO2 、CaO2 ,PaO2 CaO2,PaCO2、CaCO2,PaCO2 、CaCO2,PaCO2 N/ CaCO2 N/,34,肺A炎、肺小血管收缩、栓塞 、DIC,部分肺泡血流,2.部分肺泡血流不足 Partial alveolar hypoperfusion (VA/Q),35,病肺:PaO2 、CaO2 ,健肺:PaO2 、CaO2 ,PaO2 CaO2,PaCO2、CaCO2,PaCO2、CaCO2,PaCO2 N/ CaCO2 N/,死腔样通气,30%60-70%,部分肺泡血流 通气量正常, V/Q,气体不能被充分利用,36,Functional shunt ( local hypoventilation) Dead space like ventilation ( local hypoperfusion,