Spontaneous Breathing in Acute Respiratory Distress Syndrome

Abstract

In patients with acute respiratory distress syndrome, lung protective ventilatory strategy usually requires heavy sedation and the use of neuromuscular blocking agents because of the risk of major asynchronies and/or excessive tidal volumes in pressure control ventilation in the case of excessive patient inspiratory effort. An original approach aiming at maintaining spontaneous breathing without increasing these risks is allowed by the Airway Pressure Release Ventilation mode. In this mode, pressure control breaths are delivered and the patient can breathe spontaneously without assistance at anytime at the two pressure levels. This ventilation mode is by design asynchronous. It might allow the improvement of alveolar recruitment, in particular, in dependant zones to decrease the risk of ventilator-induced diaphragmatic dysfunction, to reduce the dose of sedative agents and the length of stay on mechanical ventilation, and to also improve hemodynamics. However, a high spontaneous breathing activity might be associated with an excessive work of breathing and an increased risk of ventilator-induced lung injury.