Providing "Good Sleep" for ICU Sedation

In this proposal the investigators seek to determine whether sedation mediated by activation of α2 adrenoceptors (dexmedetomidine) is more like natural sleep than that provided by a sedative agent that modulates the GABAA receptor (propofol), two common widely used sedative agents in ICU. Ten volunteers will be enrolled and each subject will be studied on three experimental sessions. Subjects will be randomized to receive a continuous infusion of either saline, dexmedetomidine (DEX), or propofol in each of the three sessions. By relying on clinical rating scales, the investigators ensure that the doses of DEX and propofol administered induce equisedative states before progressing to magnetoencephalography and electroencephalography data collection. If the restorative and reparative benefits of sleep mitigate the development of cognitive dysfunction, this will result in shorter ICU length of stay for critically ill patients with a concomitant reduction in healthcare costs. Furthermore, it is possible that the restorative properties of sleep for the central nervous system can extend to the immune system with less infection and/or greater likelihood of survival from sepsis. In this manner, our project will translate experimental data towards clinical practice and the adoption of rational and clinically supported interventions in the ICU that are likely to improve not only patient reported outcome measures, but also the chance of surviving critical illness. Each experimental session will take a maximum of 7 hours (5 hours maximum for control sessions). Sessions have to be separated by at least one week. Subjects will be enrolled for a minimum of 3 weeks (1 session on each week) and no more than 3 months.