respiratory failure, the inability of the cardiovascular and pulmonary systems to maintain an adequate exchange of oxygen and carbon dioxide in the lungs. Respiratory failure may be caused by a failure in oxygenation or in ventilation. Oxygenation failure is characterized by refractory hypoxemia and occurs in diseases that affect the alveoli or interstitial tissues of the lungs, such as alveolar edema, emphysema, fungal infections, leukemia, lobar pneumonia, lung carcinoma, various pneumoconioses, pulmonary eosinophilia, sarcoidosis, or tuberculosis. Ventilatory failure, characterized by increased arterial tension of carbon dioxide, occurs in acute conditions in which retained pulmonary secretions cause increased airway resistance and decreased lung compliance, as in bronchitis. Ventilation may also be reduced by depression of the respiratory center by barbiturates or opiates, hypoxia, hypercapnia, intracranial diseases, trauma, or lesions of the neuromuscular system or thoracic cage. Respiratory failure in preexisting chronic lung diseases may be precipitated by added stress, as with cardiac failure, surgery, anesthesia, or respiratory tract infections. Treatment of respiratory failure includes clearing the airways by suction, bronchodilators, or tracheostomy or endotracheal tube with ventilator support; antibiotics for infections that are usually present; anticoagulants for pulmonary thromboemboli; and electrolyte replacement in fluid imbalance. Oxygen may be administered in some cases; in others it may further decrease the respiratory reflex by removing the stimulus of a decreased level of oxygen. Chronic respiratory failure may result in cor pulmonale with congestive heart failure and respiratory acidosis. See also acute respiratory failure, airway obstruction, carbon dioxide, hypercapnia, hyperventilation, hypoxemia, hypoxia, respiratory acidosis.
