Surgical patients over 70 experience postoperative delirium (POD) complications in up to 50% of procedures. Sleep/circadian disruption has emerged as a potential risk factor for POD in epidemiological studies. However, the relationship remains unclear in a clinical setting. This protocol presents a single-site, prospective, noninvasive observational study designed to examine the relationship between sleep/circadian regulation and POD and how this association is influenced by AD pathology and genetic risk for AD. This novel approach for understanding modifiable risk factors of POD and cognitive decline after surgery could assist with establishing treatments and preventative measures for POD in the future.

Dr. Zhongcong Xie provided consulting service to Baxter Pharmaceutical company, Shanghai 9th and 10th hospital, NanoMosaic Inc., and Anesthesiology and Perioperative Science within the last 36 months. The authors have no other conflicts of interest to declare.

This study will be primarily funded by a grant award Dr. Lei Gao (PI) received from the Alzheimer's Association.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The IRB of Massachusetts General Brigham Institution gave ethical approval for this work.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study will be available upon reasonable request to the authors.