Does Nightly Dexmedetomidine Improve Sleep and Reduce Delirium in ICU Patients?

The goal of this study is to determine whether a nocturnal protocol that incorporates a pharmacologic intervention associated with improved sleep (i.e. dexmedetomidine) will improve sleep quality and reduce the incidence of delirium and sub-syndromal delirium in critically ill patients where ventilator settings have been optimized to optimize sleep quality. 1. To evaluate the impact of a dexmedetomidine-focussed nocturnal sleep protocol that minimizes arousal from sleep on: 1. incidence of delirium \[Intensive Care Delirium Screening Checklist (ICDSC) score ≥ 4\] 2. incidence of sub-syndromal delirium (ICDSC score 1-3) 3. outcomes specifically defined by place of discharge from hospital (i.e., home,rehabilitation, or long-term care) 2. To gain an understanding of the effect of night-time sedation with dexmedetomidine on: 1. patient safety 2. self-reported sleep quality 3. sleep quality and architecture \[based on a subgroup of 10 patients at Tufts Medical Center who will be evaluated using polysomnography(PSG) for one night\] 4. time spent within targeted sedation goal 5. time spent without pain 6. agitation-related events 7. length of stay in the ICU 8. duration of mechanical ventilation 9. length of hospital stay 10. total health care costs by measuring medication costs and hospitalization costs, as well as calculating effectiveness (sleep, sedation and pain management vs. cost). This multicenter study will be performed at: 1. Hopital Maissonneuve Rosemont, Montreal, PQ 2. Tufts Medical Center, Boston, MA