Diaphragm-protective mechanical ventilation in acute respiratory failure

Mechanical ventilation injures not only the lungs but also the diaphragm, resulting in dysfunction associated with poor outcomes. The chief mechanisms of ventilator-induced diaphragm dysfunction are : disuse atrophy due to insufficient contraction and excessive ventilatory support ; concentric load-induced injury due to excessive contraction and insufficient ventilatory support ; eccentric load-induced injury due to contraction during the expiratory phase ; and longitudinal atrophy caused by high positive end-expiratory pressure. To protect the diaphragm during mechanical ventilation, maintaining proper levels of diaphragm contraction is paramount ; thus, monitoring of respiratory effort and finely tuned ventilator settings are necessary. Furthermore, maintaining of synchronization between the patient and the ventilator is also important. As diaphragm dysfunction is more likely to occur in critically ill patients, diaphragm-protective mechanical ventilation strategies are essential to reduce the mortality rate of intensive care unit patients. This review outlines clinical evidence of ventilator-induced diaphragm dysfunction and its underlying mechanisms, and strategies to facilitate diaphragm-protective mechanical ventilation.