Cognitive Protection - Dexmedetomidine and Cognitive Reserve

Elderly patients who undergo anesthesia and non-cardiac surgery are subject to deterioration of brain function including the development of postoperative delirium (PD) and postoperative cognitive dysfunction (POCD). These disorders cause disability, distress for both patients and their families, are associated with other medical complications and account for significant additional health care costs. We currently use relatively primitive approaches to preventing and treating PD and POCD. The proposed is a pilot study for an NIH grant which was recently submitted. This is a randomized controlled trial of perioperative dexmedetomidine to prevent PD and, potentially, POCD. Fifty patients will be enrolled at Mount Sinai with two different surgeries, either hip replacement or vascular bypass. The patients undergoing hip replacement will receive dexmedetomidine until discharge from the PACU. Vascular surgery patients who are transferred from the PACU to a monitored step-sown unit will continue dexmedetomidine for 24 hours.Participants will be screened for Mild Cognitive Impairment (MCI), and undergo preoperative cognitive testing. Unlike the parent trial, we will test for but will not select for patients with MCI. Participants will be randomized to either dexmedetomidine or placebo which will be started prior to surgery and continued for 24 hours postoperatively. Follow up studies will include surveillance for delirium while in the hospital and cognitive testing at 3 months following surgery.

Dexmedetomidine is a drug used for sedation in critically ill patients that provides some pain relief and controls the bodies response to stress. The sedation produced by dexmedetomidine appears more similar to natural sleep than any other drug used for anesthesia and postoperative sedation. Data suggesting that dexmedetomidine can prevent delirium following cardiac surgery and the developing understanding of the causes of PD and POCD suggest that dexmedetomidine will be particularly effective.