Preoperative cognitive impairment (PCI) may increase the incidence of postoperative delirium (POD), yet screening for cognitive impairment is rarely performed. This study hypothesized that Mini-Cog for preoperative cognitive impairment screening predicts postoperative delirium. Elderly patients (65 years or older) attending Henan Provincial People's Hospital during the trial period who required elective thoracic surgery were recruited into the study.

We collected data points on demographics and hospital episodes through the electronic medical record the day before surgery. Cognitive function screening (Mini-Cog; the Mini-mental State Examination, MMSE), depression screening (Patient Health Questionnaire-9, PHQ-9), sleep quality assessment (Pittsburgh Sleep Quality Index, PSQI), and pain assessment (Numeric Rating Scale, NRS) were performed, and the time spent on Mini-Cog test and MMSE assessment was recorded. The Short Confusion Assessment Method (CAM) was administered once per day on postoperative days 1 to 5 to evaluate delirium.

Inclusion Criteria:

1. 65 years of age or older,
2. elective thoracic surgery,
3. under general anesthesia.

Exclusion Criteria:

1. history of psychiatric disorders,
2. use of any antipsychotic drugs,
3. ASA score >3
4. severe visual, hearing, or physical dysfunction unable to complete the scale
5. advanced malignant tumors of the chest with distant metastases to bone, liver, etc.,
6. history of general anesthesia surgery in the last six months.

Elderly patients attending Henan Provincial People's Hospital during the trial period who required elective thoracic surgery