Abstract:Significant advances in the physiological concepts, diagnosis and therapy of respiratory failure are reviewed. The etiology of the respiratory failure in a given patient can be deduced by studying the ventilation, perfusion, diffusion and distribution of the inspired air. This assessment and a knowledge of the mechanics of ventilation are essential for the determination of specific therapy. Curves for bicarbonate and arterial carbon dioxide tension in animals, in normal persons and in patients with chronic pulmonary disease are discussed with regard to their clinical applications.Cardiovascular complications and neuromuscular and cerebrovascular changes due to acute relative hypocapnia and hyperbasemia induced by inadvertent mechanical hyperventilation are the most common hazards of artificial or assisted ventilation. Clinical and chemical recognition of these states by means of blood gas analyses enables prompt correction, accomplished by increasing deadspace ventilation, reducing the respiratory rate, and giving acetazolamide. In respiratory failure, the administration of oxygen is essential for the correction of hypoxia. When the respiratory failure is caused by an acute exacerbation of chronic pulmonary disease, the corrective oxygen concentrations should be kept strictly within the range of 21 to 35 per cent.