REPOSE Study: Reducing Delirium by Enhancing Postoperative Sleep With Suvorexant

This research study will evaluate the effectiveness of postoperative administration of a drug called suvorexant, to improve postoperative sleep and decrease the severity of delirium (serious confusion) in adults 65 years and older undergoing non-cardiac surgery.

Suvorexant is an FDA-approved drug to treat a condition called insomnia, a sleep disorder characterized by difficulty falling asleep, staying asleep or getting good quality sleep, and has been found to have a good safety profile in older adults. Since older surgical patients often have difficulties with sleep, suvorexant might improve sleep after surgery but this remains unknown. Because difficulties with sleeping after surgery have been associated with a disorder of severe confusion called delirium, administration of suvorexant after surgery may also help prevent delirium or decrease its severity. Participants will receive either a placebo or suvorexant by mouth (or feeding tube if present) on the first three nights after surgery while in the hospital. Prior to surgery, participants will be asked to wear a wristband sleep monitor and complete several questionnaires about their sleep, brief thinking and memory tests, a test of attention, and a measurement of their pupil size with a special camera. After surgery, participants will wear a comfortable headband device that records the electrical signals from the brain to measure the amount and depth of their sleep. This device will be worn for the first 3 nights from 9:00 PM to 6:00 AM after surgery or until hospital discharge, whichever occurs first. After surgery, participants will also answer several questions about their sleep quality and redo some of the brief thinking and memory tests (delirium tests), attention tests, and pupil size measurements. Additionally, the investigators will collect a blood sample prior to surgery and on the first two days after surgery. Benefits of this study include the possibility of improved sleep after surgery and fewer problems with confusion and thinking and memory problems after surgery. Risks of participation include headache, diarrhea, dry mouth, cough, abnormal dreams, dizziness, daytime tiredness and discomfort from the blood draw.