Daridorexant to Prevent Post-cardiotomy Delirium

The goal of this follow-on pilot randomized clinical trial is to obtain additional preliminary data to inform a larger, adequately powered phase 2b trial of daridorexant for the prevention of postoperative delirium after heart surgery. Having demonstrated feasibility in a prior study (RSRB #9841), this study aims to estimate the effect of daridorexant on (1) reducing delirium symptom burden and incidence and (2) improving self-reported sleep quality during the postoperative period, and (3) to assess the feasibility of collecting objective sleep data in the postoperative setting. Participants will: complete a baseline visit; take the study drug, either daridorexant or placebo, each of the first three nights after heart surgery; and be evaluated daily for sleep and delirium during the first three postoperative days. Participants will also have the option of wearing a sleep monitor in the hospital each of the first three nights after surgery.