ABSTRACT
Respiratory insufficiency represents the final common pathway of pathologies that brings disequilibrium between respiratory needs of the organism and performance of the respiratory apparatus. To orient the diagnostic and therapeutic steps, this chapter generally distinguishes four types of acute respiratory insufficiency: related to upper airways obstruction, hypoxemic, hypercapnic, and mixed. The etiology, physiopathology, and diagnostic and therapeutic approaches of these conditions are specified with each entity. The acute hypoxemia encountered in clinical settings is most often a manifestation of one of the three following phenomena, either isolated or associated: shunt, ventilation/perfusion (V?/Q?) mismatch, and alveolar hypoventilation. Two main types of ventilatory apparatus defects produce alveolar hypoventilation and cause a retention of CO2: disorders of ventilatory rhythm and effector ventilatory apparatus insufficiency. The first intervention to offer to the hypoxemic patient will be oxygen supplementation according to the mode of administration and the flow of oxygen chosen.
