failure呼吸衰竭课件.ppt

Respiratory failure Department of respiratory medicine Xuanwu hospital Definition Respiratory failure is defined as a dysfunction of gas exchange resulting in abnormalities of oxygenation or carbon dioxide elimination severe enough to impair or threaten the function of vital organs. Respiratory failure is defined as a PaO2 60mmHg. Classification Acute or chronic Type Ⅰ respiratory failure or type Ⅱ respiratory failure depending on the PaCO2. Classification Type Ⅰ respiratory failure: hypoxia is combined with a normal or low pCO2 (50mmHg). type Ⅱ respiratory failure: hypoxia is combined with a raised pCO2 (50mmHg). Mechanisms of arterial hypoxemia Inhalation of hypoxic gas mixture or severe reduction of barometric pressure. Hypoventilation Impaired alveolar diffusion of O2 Ventilation-perfusion mismatching Shunting of systemic venous blood to the systemic arterial circuit Abnormal desaturation of systemic venous blood. Causes: Type Ⅰ respiratory failure Pneumonia Asthma COPD (predominant emphysema—pink puffers’) Pulmonary thromboembolism Acute respiratory distress syndrome and non-cardiogenic pulmonary edema Cardiogenic shock Tension pneumothorax Pulmonary fibrosis Causes: Type Ⅱ respiratory failure COPD (predominant chronic bronchitis—blue bloaters’) Respiratory muscles failure Kyphoscolisis and other structure thoracic disorders Muscular dystrophy Sleep apnea Clinical findings Underlying disease; Hypoxemia: CO2 retention: The symptoms and signs of acute respiratory failure are both insensitive and nonspecific. Clinical findings -hypoxemia The chief symptom of hypoxemia is dyspnea. Signs of hypoxemia include cyanosis, restlessness, confusion, anxiety, delirium, tachypnea, tachycardia, hypertension, cardiac arrhythmias, and tremor. Clinical findings –CO2 retention Dyspnea and headache are the cardinal symptoms of hypercapnia. Sings of hypercapnia include peripheral and conjunctival hyperemia, hypertension, tachycardia, tachypnea, impaired consciousness, papil