Up to 80% of patients undergoing intensive care have delirium. Early in the ICU stay, delirium and agitation are usually prevented using analgesic and sedative drugs which essentially render the patient unconscious. This is appropriate in the context of aggressive treatment of pathophysiological instability, which often requires multiple painful procedures. However, after the underlying pathophysiological problem has resolved, patients sometimes remain delirious and agitated. This often requires ongoing heavy sedation, which in turn necessitates continued mechanical ventilation, and can worsen the (temporarily masked) delirium. Prolonged mechanical ventilation increases the risk of ventilator associated pneumonia and other life threatening complications.