In the early phase of their disease process, patients with acute lung injury are often ventilated with strategies that control the tidal volume or airway pressure, while modes employing spontaneous breathing are applied later to wean the patient from the ventilator. Spontaneous breathing modes may integrate intrinsic feedback mechanisms that should help prevent ventilator-induced lung injury, and should improve synchrony between the ventilator and the patient's demand. Airway pressure release ventilation with spontaneous breathing was shown to decrease cyclic collapse/recruitment of dependent, juxtadiaphragmatic lung areas compared with airway pressure release ventilation without spontaneous breathing. Combined with previous data demonstrating improved cardiorespiratory variables, airway pressure release ventilation with spontaneous breathing may turn out to be a less injurious ventilatory strategy.