呼吸衰竭,Respiratory Failure呼吸内科 阙呈立,www.themegallery.com,Definition & Classification,Failure of gas exchange due to inadequate function of one or more essential components of respiratory system; Manifested as: Hypoxemia (PaO2 50 mmHg );,www.themegallery.com,定义,在海平面上； 吸空气的情况下； 静息； PaO2 50 mmHg (6.7 kPa).,www.themegallery.com,定义中的问题,吸氧情况下PaO250 mmHg非II型呼吸衰竭; 代谢性酸中毒时, 即使PaCO250 mmHg, 仍可考虑存在II型呼吸衰竭;,www.themegallery.com,分型（1）,按血气： I型(oxygenation failure)： PaO2 50 mmHg。 III: Perioperative failure, IV: circulatory failure;,www.themegallery.com,分型（2）,按出现的快慢关系到治疗： 急性：一般存在pH改变, 可以迅速致命 慢性：pH可能在正常范围 慢性基础上急性加重（acute on chronic),www.themegallery.com,流行病学,收住内科ICU的最常见原因; 137/100,000 population, or 360,000/yr in US; 36%在住院期间死亡； 发病率和死亡率随年龄和合并的疾病上升；,www.themegallery.com,生理 五个成分的整合功能,1。神经系统（延髓的背侧核和腹侧核， 传出传入神经+皮质：呼吸频率和呼吸的努力程度） 控制器衰竭/中枢性呼吸暂停； 2。肌肉（泵，包括胸壁的支持结构） 泵衰竭； 3。气道（从上气道-终末细支气管） 气路系统衰竭； 4。肺泡（呼吸性细支气管，肺泡管，肺泡） 肺泡腔衰竭； 5。血管（肺血管网） 肺血管衰竭；,www.themegallery.com,呼吸衰竭的生理,任何一个成分的衰竭, 或几个部件的功能不全呼吸衰竭; 不同成分造成的呼吸衰竭治疗手段不同; 如I型呼衰(哮喘, 肺栓塞, 肺水肿);,www.themegallery.com,Causes Of Respiratory Failure,www.themegallery.com,呼吸衰竭的病因,I型呼衰 心源性肺水肿; 非心源性肺水肿; 肺栓塞(血栓,空气,脂肪) 肺炎; 肺出血;,II型呼衰 中枢抑制; 格林-巴利综合征; 肌肉病; 呼吸肌疲劳; 气道阻塞:哮喘, COPD;,www.themegallery.com,呼吸衰竭的病因,II型呼衰可由肺或非肺脏原因引起： 中枢神经系统受抑; 严重的阻塞性肺病; 肌肉的无力; 除环境因素, I型呼衰提示累及肺实质或肺循环;,www.themegallery.com,低氧血症的机制,吸入氧分压低 低通气 弥散障碍 通气/血流比不匹配 右左分流,www.themegallery.com,低氧和高碳酸血症的机制,所有引起呼吸衰竭的病因均导致低氧血症; 通气血流比不匹配是低氧血症的主要原因，即使在弥散障碍的情况下，也存在相当的通气血流比失调。 低氧血症的五个原因中，CO2分压的增加是由于肺泡低通气引起;,www.themegallery.com,急性呼吸衰竭的危险因素,手术后 原有慢性疾病 营养不良 年迈 病态肥胖 慢性支气管炎 吸烟,www.themegallery.com,Hypoxemia & Hypoxia,Hypoxemia: low PaO2 (a, v, cap), or low O2 content or reduced SaO2; Hypoxia: decreased O2 delivery to the tissues or the effects of decreased tissue O2 delivery; Hypoxia will result from severe hypoxemia, but can also be a consequence of low CO, anemia, septic shock, or CO poisoning (PaO2 may be normal or even elevated),www.themegallery.com,症状和体征,-取决于原发病 例如哮喘， COPD 呼吸中枢抑制 -及缺氧和二氧化碳潴留的症状,www.themegallery.com,Clinical Features,I型呼吸衰竭： 动脉低氧血症和组织缺氧共同作用的结果； 轻度缺氧精神活动的障碍（抽象思维等） 缺氧加重神志改变：嗜睡，昏迷，惊厥及永久脑损害；交感神经活性：HR ,血管收缩, BP , 出汗; 严重缺氧HR,血管扩张, BP , 心肌缺血, 梗死, 心律失常, 和心衰;,www.themegallery.com,Clinical Manifestations of Hypercapnia and Hypoxemia,Hypercapnia Headche Peripheral vasodilation Tachycardia Papilledema Bounding pulse Restlessness Tremor Slurred speech Lethargy Somnlence,Hypoxemia Dyspnea Cyanosis Tachycardia Arrhythmia Diaphoresis Agitation Confusion Hypertension/ Hypotension Seizures,www.themegallery.com,Clinical Manifestations,低pH而非PaCO2的绝对水平与神志和其它临床改变关系更密切 急性CO2主要作用于CNS: PaCO2主要通过CSF中的pH抑制CNS; 慢性CO2 血清和CSF中的HCO3-代偿;,www.themegallery.com,Initial Clinical Evaluation,Upper airway patency and central or peripheral cyanosis; RR and depth/pattern of respiration Respir Drive; Respiratory distress (flaring of nostrils, pursed-lip breathing, use of accessory muscles) Pump function ; Configuration of chest wall and its movement Pump function ; Auscultate over each hemithorax gas Deliveray Pulse oximetry ABG,www.themegallery.com,进一步检查,ABG CXR Sputum/Blood Culture (if febrile) CBC, CRP, U&E etc,www.themegallery.com,When to consider ABG,An unexpected deterioration in an ill patient; Anyone with an acute exacerbation of a chronic chest condition; Anyone with impaired consciousness; Anyone with impaired respiratory effort; Bounding pulse, drowsy, tremor, headache, pink palms, papilloedema; Cyanosis, confusion, visual hallucinations,www.themegallery.com,呼吸衰竭的治疗,原则：先稳定病情再寻找原发病 氧合与通气的支持; 针对呼吸系统原发病的特异性治疗; 无论呼吸系统疾病的类型, 支持治疗总的原则是类似的; I型呼衰: 供氧(机械通气, PEEP); II型呼衰: 改善肺泡通气(通畅气道或机械辅助),www.themegallery.com,Stabilization of Respiratory Failure,Initial threapy be implemented before the specific etiology of the respiratory failure is diagnosed & treated Adequate airway protection Oxygenation Ventilation From the standpoint of RF, the 1st priority is to establish adequate oxygenation & ventilation,www.themegallery.com,Stabilization of RF (contd),Administration of O2 might be all that is initially required If the patient is in distress, mechanical ventilation (NPPV or intubation) is needed Cardiovascular stability must also be rapidly assessed & achieved Following stabilization, a systematic & thorough evaluation of the cause of RF can safely be carried out,www.themegallery.com,呼吸衰竭病因的确定,www.themegallery.com,动脉血气分析： (A-a)DO2,PAO2 = FIO2(PB-PH2O) - PaCO2 / R （A-a)DO2正常（换气正常）： 吸入氧过低 低通气 （A-a)DO2： 分流：一部分去饱和的血液未在肺泡氧和 补充O2相对无效； V/Q失调：高V/Q区域的高PO2并不能显著增加SO2及CtO2，因此不能代偿低V/Q区的低SO2 补充O2可提高低V/Q区的PO2 ；,www.themegallery.com,动脉血气分析：PaCO2 ,根本的机制：肺泡通气量 CO2的产生量 CO2产生 呼吸驱动 呼吸泵功能 气道阻力 气体交换效率(死腔 ),www.themegallery.com,治疗（）,一般治疗： 保持气道通畅； 氧疗 某些情况下需机械通气,www.themegallery.com,治疗（）,特异性治疗： 抗生素 支气管扩张剂（） 糖皮质激素？,www.themegallery.com,Treatment,The effective management of RF depends on identifying and optimally managing all of the treatable factors that impair the respiratory system: Removing excess secretion Treating infection w. antimicrobials Treating obstruction w. bronchodilators Dissolving blood clots w. anticoagulants/thrombolysis Removing transudated fluid w. diuretics CPAP or Lung transplant etc.,