Abstract： @@ Acute respiratory failure is the most frequent indication for the application of mechanical ventilation. 1 As commonly used in clinical settings, lung protective strategies and recruitment manoeuvres are applications of higher than normal airway pressure to open the collapsed alveoli and prevent lung atelectasis caused by minimal vital ventilation. Under those conditions, we pay more attention to the lung injury and circulatory failure, and less attention to the diaphragmatic structure and function.