Study design and participants
cognitive disorder, psychiatric
This prospective, randomized, double‐blinded study was performed at Vilnius University Hospital Santaros Klinikos (Vilnius, Lithuania) over a two‐year period (December 1, 2017 to December 1, 2019). The approval for the trial was obtained from the Vilnius Regional Biomedical Research Ethics Committee (Approval No. 158200‐17‐949‐453; Date: September 12, 2017). All eligible patients were provided with the information about the study and signed an informed consent form on the day of inclusion.Patients were invited to take part in the trial if they fit the following criteria: elective thyroid surgery under general anesthesia, hospitalization at least one day before the surgery and age ≥40 years. Those who refused to participate or continue participation, did not speak Lithuanian, or had been prediagnosed with neurological, psychiatric, or cognitive disorder were excluded from the study. Participants were also eliminated from the study if they were discharged less than 24 h after the surgery (Figure CONSORT flowchart of study participants.