Acute respiratory failure is common in patients with acute lung injury. MV re-establishes adequate gas exchange; it allows time for administration of antibiotics, for the host's immune system to fight infections, and for natural healing. Approximately 60% of ALI patients survive to hospital discharge (1). However, conventional approaches to MV in ALI frequently cause dyssynchrony between a patient's spontaneous respiratory efforts and the ventilator's respiratory cycle (2;3). Dyssynchrony causes discomfort, anxiety, and agitation. To manage dyssynchrony, physicians frequently prescribe large doses of sedative and analgesic medications. These medications contribute to delirium and sleep deprivation during the critical illness, and may delay weaning from MV and discharge from the intensive care unit (2;4). They may also contribute significantly to neuromuscular and neurocognitive sequelae after recovery from ALI (5;6). Moreover, MV may itself cause additional lung injury (ventilator-induced lung injury, VILI) which could, paradoxically, delay or prevent recovery from respiratory failure in some ALI patients (7;9).