 Patients with primary brain injury or prolonged weakness are excluded. Participants will be randomized into one of 2 study groups. All patients will receive adequate analgesia at randomization at the discretion of treating clinician. All randomized patients will have Light sedation as the default target unless otherwise clinically indicated. The intervention group will receive EGDS with dexmedetomidine as the primary sedative agent to achieve light sedation, with the addition of propofol as required. The use of benzodiazepines in the intervention group is not allowed, with the exception of specific, defined circumstances. 