Effects of TEAS on POCD

Patients undergoing elective orthopedics, urology, and general surgery will be included and randomly allocated to TEAS group or control group . After routine anesthesia induction and tracheal intubation, patients in TEAS group will receive electrical stimulation of acupoints at Neiguan and Shenmen points. For patients in the control group, the electrodes will be only attached to the corresponding sites, with no TEAS electrical stimulation given during the operation. The primary outcome is the incidence of POCD at Day 7 after surgery. The secondary outcomes include the incidence of POD during post-operative days 1-7, the incidence of POCD at Day 30 after surgery, and the serum levels of cytokines, including IL-1β、IL-6、TNF-α、MMP9 on Day 1 after surgery.