The aim of this clinical trial is to study the effect of transcutaneous electrical acupoint stimulation combined with auricular vagus nerve stimulation on postoperative delirium in elderly patients undergoing gastrointestinal surgery. The study aims to answer the following main questions

1. whether it reduces the expression of inflammatory factors in the acute postoperative period
2. whether it can reduce the incidence of postoperative delirium

Existing clinical studies have shown that TEAS has demonstrated value in preventing postoperative delirium (POD). Currently, taVNS is commonly used clinically to improve patients' cognitive dysfunction (POCD), and POD is often considered a precursor to the development of POCD. However, no one has yet used the two in combination, so this study aimed to combine the two to investigate their potential benefits in preventing POD.

Inclusion Criteria:

1. Aged ≥65 years;
2. Body mass index (BMI) 18-30 kg/m²;
3. American Society of Anesthesiologists (ASA) physical status classification I-III;
4. Patients scheduled for elective laparoscopic gastrointestinal surgery;
5. Willingness to provide written informed consent and comply with the treatment regimen;
6. Absence of severe organic diseases, psychiatric disorders, or preoperative delirium.

Exclusion Criteria:

1. Preoperative Mini-Mental State Examination (MMSE) score <20;
2. Electrocardiographic evidence of severe bradycardia (heart rate <50 beats per minute);
3. Presence of skin lesions or infections at the electrical stimulation site;
4. History of preoperative chemotherapy or radiotherapy;
5. Concomitant severe organic diseases with compromised tolerance to interventions;
6. Prior exposure to Transcutaneous Electrical Acupoint Stimulation (TEAS) or transcutaneous auricular vagus nerve stimulation (taVNS) with documented insensitivity;
7. Inability to communicate normally, dementia, hearing impairment, or severe psychiatric disorders.

The IPDs collected in the experiment were published only as the results of the paper