呼吸衰竭 Respiratory failure
外呼吸 呼吸功能
气体运输 外呼吸 呼吸功能 内呼吸
、概念与分类( Concept& Classification) 1.呼吸衰竭( Respiratory Failure) 在海平面静息状态吸入空气的情况下,由于肺通气和(或)换 气功能的严重障碍,以致P尸aO2低于8.0kPa(<60mmHg),伴有或 不伴有PaCO2高于6.67kPa(50mmHg)的病理过程。 Respiratory failure is a syndrome in which the respiratory system fails in one or both of its gas exchange functions oxygenation and carbon dioxide elimination In practice, respiratory failure is defined as a Pao2 value of less than 60 mm Hg while breathing air or a Paco2 of more than 50 mm Hg. (mmHg=millimeter hydrargyrum
Concept & Classification Respiratory failure is a syndrome in which the respiratory system fails in one or both of its gas exchange functions: oxygenation and carbon dioxide elimination. In practice, respiratory failure is defined as a PaO2 value of less than 60 mm Hg while breathing air or a PaCO2 of more than 50 mm Hg. （mmHg=millimeter hydrargyrum）
【呼吸衰竭指数】( Respiratory failure index,RF|) 计算公式 RF|=PaO/FiO2(100/0.2) RF|≤300可诊断为呼吸衰竭 【呼吸功能不全】( Respiratory insufficiency) ▲PaO2或PaCO2个没有达到上述水平,或在静息时血气 值正常。 ▲没有明显的临床症状,但当体力负荷增加时PaO2才明显 降低或伴有PaCO2水平增高
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2. Classification (1) According to Paco 2 a(Type 1) respiratory failure Hypoxemic respiratory failure a Pao2 of less than 60 mm Hg with a normal or low Paco2 Cause of: Edema. vascular disease. Chest Wall& Pleural disease a(Type ll)respiratory failure( Hypercapnic respiratory failure - a Pao2 low 60 mm Hg and PaCcO, of more than 50 mm Hg Cause of: Airway obstruction, Neuromuscular disease
Type Hypercapnic respiratory failure） a PaO2 low 60 mm Hg and PaCO2 of more than 50 mm Hg. Cause of：Airway obstruction, Neuromuscular disease. Type I Hypoxemic respiratory failure） a PaO2 of less than 60 mm Hg with a normal or low PaCO2 . Cause of：Edema, Vascular disease, Chest Wall & Pleural disease
(2) According to primary site a Centrol respiratory failure a Non-Centrol respiratory failure. (3) According to duration aAcute respiratory failur a Chronic respiratory failure
、原因和机制( Causes& mechanism) Classification of respiration failure mechanism) Restrictive ventilatory disorders 1. Ventilatory disorders Obstructive ventilatory disorders Diffusion disorders 2. Gas exchange disorders Ventilation-perfusion mismatching (Increased of anatomica/ shunt (一)肺通气功能障碍( Ventilatory disorders) 1. Etiologies and mechanisms of alveolar hypoventilation (1)限制性通气不足( Restrictive ventilatory disorders) 由于肺泡扩张受限引起肺泡通气量不足—→限制性通气不足
（一） （Ventilatory disorders） 1. Ventilatory disorders 2. Gas exchange disorders Diffusion disorders Ventilation-perfusion mismatching （Increased of anatomical shunt） Restrictive ventilatory disorders Obstructive ventilatory disorders
肺泡扩张的动力不足( Hypo-motility of pulmonary ventilation) ▲CNS受损 呼吸中枢(-)E>呼吸肌运动↓(泵衰竭) ▲麻醉、安眠药过量 ▲周围神经系统病变 ▲呼吸肌疲劳、呼吸肌萎缩 呼吸肌活动障碍 ▲严重低钾血症、缺氧、酸中毒 ▲胸廓和胸腔疾病( Disorders of chest wa∥) 胸廓扩张受限(泵衰竭)→肺泡扩张动力不足 呼衰PaO2l、PaCO2↑肺有效通气量↓
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肺泡扩张的阻力增加( Increased ventilation resistance) 【肺的顺应性】 (正常成年人肺顺应性为0.2 LemH,O) 肺的顺应性{肺容量 肺弹性阻力 胸壁和肺的弹性回缩力{肺泡表面张力 ▲胸壁弹性阻力增加 胸廓畸形、胸膜纤维化、胸腔积液今胸壁的弹性阻力↑ 胸腔大量积液、张力性气胸 严重的腹水、肝脾肿大 肺泡扩张受限 肺泡于张的阻力 肺顺应性 呼衰肺有效通气量令一限制性通气不足
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▲肺组织顺应性下降( The lungs compliance↓ 肺水肿、 肺泡表面活性物 急性胰腺炎 质分泌!、分解↑ 肺栓塞、氧中 肺泡表面张力 Ⅱ型肺泡上皮受损 毒、毒气中毒 肺纤维化 肺顺应性↓ 肺泡扩张的 呼衰 限制性通气不足 阻力↑
肺栓塞、氧中 毒、毒气中毒 Ⅱ型肺泡上皮受损 肺 泡 表 面 张 力 ↑ 肺水肿、 急性胰腺炎 肺泡表面活性物 质分泌↓、分解↑ 肺顺应性↓ ▲ The lung‘s compliance↓） 肺泡扩张的 阻力↑ 呼衰 限制性通气不足 肺纤维化