Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsFJ conceived the study protocol. FST, FJ, PFL, TD, and HS participated in the design and coordination of the study. FST, JLV, and FJ drafted the present manuscript. All authors read and approved further info the final manuscript.AcknowledgementsWe thank all the nurses and doctors who contributed to this study. The study was supported by grants from AstraZeneca, Wyeth Pharmaceuticals, GlaxoSmithKline Pharmaceuticals, and Bristol-Myers Squibb.
Recent advances in critical care medicine have identified acute brain dysfunction (delirium and coma) as a highly prevalent manifestation of organ failure in critically ill patients that is associated with increased morbidity and mortality [1-6].

Accumulating evidence also shows that the degree [7] and duration [3,8] of acute brain dysfunction are important risk factors for adverse clinical outcomes. The presence of delirium and coma can potentially worsen outcomes in septic patients [9-11]; this may be linked to septic perturbation of inflammatory, coagulopathic and neurochemical mechanisms that can contribute to the pathogenesis of acute brain dysfunction [12,13].Sedative and analgesic medications, routinely administered to mechanically ventilated (MV) patients [14], contribute to increased time on MV and ICU length of stay [15]. Benzodiazepines, in particular, enhance the risk of developing acute brain dysfunction [6,16-18].

Other studies have demonstrated that benzodiazepines are associated with worse clinical outcomes when compared with either propofol or with opioid-based sedation regimens [19,20], although these studies did not evaluate the role of changing sedation Batimastat paradigms on acute brain dysfunction.The Maximizing Efficacy of Targeted Sedation and Reducing Neurological Dysfunction (MENDS) trial [21] demonstrated that dexmedetomidine (DEX) [22], an alpha2 (��2) adrenoceptor agonist, provided safe and efficacious sedation in critically ill MV patients, with significant improvement in brain organ dysfunction (delirium and coma) compared with the benzodiazepine, lorazepam (LZ).