failure呼吸衰竭课件

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 respiratory failure or type respiratory failure depending on the PaCO2. Classification Type respiratory failure: hypoxia is combined with a normal or low pCO2 (50mmHg). type 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 respiratory failure Pneumonia Asthma COPD (predominant emphysemapink puffers) Pulmonary thromboembolism Acute respiratory distress syndrome and non- cardiogenic pulmonary edema Cardiogenic shock Tension pneumothorax Pulmonary fibrosis Causes: Type 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, papilledema, and asterixis. Treatment of respiratory failure Specific therapy directed toward the underlying disease; Respiratory supportive care directed toward the maintenance of adequate gas exchange; General supportive care. Respiratory support Nonventilatory aspects Ventilatory aspects Nonventilatory aspects Non-invasive +ve pressure -ve pressure CPAP BiPAP Iron lung Ventilatory aspect Maintaining patency of the airway Ensuring adequate alveolar ventilation Tracheal intubation Indications: (1) hypoxemia is not quickly reversed by supplemental oxygen, (2) upper airway obstruction, (3) impaired airway protection, (4) inadequate handling of secretions, (5) facilitation of mechanical ventilation. Ways: orotracheal and nasotracheal intubation. Mechanical ventilation Indications: (1)apnea, (2) acute hypercapnia is not quickly reversed by therapy, (3)severe hypoxemia, (4) progressive patient fatigue. Mechanical ventilation:types invasive IPPV Full supportPartial support CMV SIMV, PSV volume pressure Mechanical ventilation:complications Migration of the tip of the endotracheal tube into main bronchus; Barotrauma; Volutrauma; Acute respiratory alkalosis Hypotension Ventilator-associated pneumonia General supportive care Adequate nutrition and hydration Electrolyte balance Avoid stress gastritis, ulcer, deep venous thrombosis, and pulmonary embolism. Psychologic and emotional support Chronic respiratory failure definition The term chronic respiratory failure refers to a persistent inability to maintain normal gas exchange. Ventilatory failure. Pathophysiology of chronic respiratory failure Impaired ventilatory control Neuromuscular disorders Chest wall abnormalities Airway obstruction Reduced lung compliance Causes of chronic respiratory failure Chronic obstructive pulmonary disease Obstructive sleep apnea syndrome Chest wall deformity Muscular dystrophy Interstitial lung disease Clinical findings of chronic respiratory failure Patient with chronic respiratory failure secondary to severe lung disease have prominent respiratory symptoms. Secondary to neuromuscular disease, central ventilator defect, few or no respiratory symptoms, due to CO2 retention, disrupt normal sleep patterns, fretful sleep, nightmare, morning headaches. During the day, fatigue, mood disorders. Clinical findings of chronic respiratory failure Although the signs of chronic respiratory failure are non-specific, the physical examination is nevertheless very important for detecting predisposing illness. Diagnostic studies for patient with chronic respiratory failure History and physical examination Arterial blood gases Laboratory studies: complete blood cell count, serum electrolytes, thyroid function test Pulmonary function test Nocturnal polysomnography Therapy of chronic respiratory failure Reversal of contributing factors Pharmacologic management Continuous positive airway pressure Noninvasive ventilation Reversal of contributing factors The reversal of airway obstruction with bronchodilators or steroids, treatment of congestive hear failure with diuretics, and correction of metabolic alkalosis may be the only interventions necessary to normalize ventilation. Pharmacologic management To enhance respiratory drive in patient with chronic respiratory failure. Continuous positive airway pressure CPAP has become the therapy of the choice for symptomatic OSA and can be effective in reversing chronic respiratory failure secondary to OSA, cong