A Study on the Efficacy and Mechanism of Combined Acupuncture and Medication Strategy in Preventing Postoperative Delirium in Elderly Patients

INTERVENTION: control group:Patients do not use TEAS or the buccal acupuncture therapy intervention during surgery;TEAS group:After the surgery begins, the patient used the fifth generation HANS transcutaneous acupoint electrical stimulator (JS‐502‐A type, Beijing) to stimulate the Baihui and Neiguan acupoints for treatment until the end of the surgery. The current intensity was set to 1 mA, and the frequency was 4/20Hz. The sparse wave was used to stimulate the muscles to achieve slight tremors;sham TEAS group:The intervention method is similar to the TEAS group, but only applies electrode patches to acupoints without electricity;the buccal acupuncture therapy group:After anesthesia,the buccal acupuncture (disposable sterile needle 0.18mmX30mm) were administered to the upper and middle Jiao points (located at the intersection of the mandibular coronoid process and the lower edge of the zygomatic arch), lower Jiao points (located at the midpoint of the line connecting the upper and lower Jiao points), neck points (located at the upper edge of the zygomatic arch root), back points (located below the temporomandibular joint below the zygomatic arch root), waist points (located at the midpoint of the line connecting the back and sacral points), lower waist points (located at the middle and lower 2/3 points of the line connecting the waist and sacral points), sacral points (located 0.5 inches in front of the mandibular angle), and hip points (located at the front of the masseter muscle and 1 inch in front of the mandibular angle). the buccal acupuncture were left for 30 minutes during surgery.; CONDITION: Postoperative delirium after radical gastrectomy PRIMARY OUTCOME: The incidence of postoperative delirium at discharge or within 5 days after surgery; SECONDARY OUTCOME: Assess the Pittsburgh Sleep Quality Inde Xscore from postoperative day 1 to day 5 (before discharge);Hospital Anxiety and Depression Scale score;Postoperative pain score;Changes in inflammatory factors related to postoperative delirium compared to preoperative levels;Evaluate Charlson's comorbidity inde Xscore;Assessment of Consciousness Status (Delirium assessment method) Score;Integrating brain structure and functional imaging through functional magnetic resonance imaging (fMRI) and EEG techniques, dynamically observing the time‐varying mapping relationship of brain functional activity intensity, and evaluating changes in fiber bundle structure connections and functional connections between the hippocampus and prefrontal cortex; INCLUSION CRITERIA: 1. Age greater than or equal to 65 years old; 2.American Society of Anesthesiologists (ASA)physical status of II to III; 3. Intending to perform medium to high‐risk III/IV level surgeries, 4.including laparoscopic radical gastrectomy and open radical gastrectomy for gastric cancer; 5. Patients with 2 or more of the following diseases: hypertension, diabetes, coronary heart disease, central nervous system diseases (cerebral infarction, coelomic infarction, white matter lesions), chronic obstructive pulmonary disease; 6. Postoperative plan to admit patients to the intensive care unit