Barotraumatisme lors de la ventilation mécanique

Mechanical ventilation is a vital support in patients with acute respiratory failure improving oxygenation but with the potential to worsen lung injury. Acute respiratory distress syndrome (ARDS) is characterized by bilateral pulmonary infiltrates and stiff lung with a decreased lung compliance responsible for high alveolar pressure even using low tidal volume. Alveolar overdistension induced by mechanical ventilation can cause barotrauma because of bronchial or alveolar rupture. The visible injury is an air leak detected by chest X-ray: pneumothorax or pneumomediastinum. Risk factors associated with barotrauma are the underlying disease for mechanical ventilation and an high airway pressure during mechanical ventilation. The incidence of pneumothorax during ARDS is less than 10% since reduction of tidal volume and limitation of plateau pressure. Alveolar pressure is obtained by measuring plateau pressure at the end of the inspiration. Plateau pressure is the best tool to evaluate the risk of alveolar overdistension. This pressure must be kept below 30 cmH2O.