Patients who meet the enrollment criteria will be randomized 1:1 to either the transcutaneous electrical acupoint stimulation (TEAS) or the sham groups. In the TEAS group, the acupoints are bilateral neiguan (PC6), Zusanli (ST 36), Hegu (L14) and Waiguan (SJ5) acupoints. The treatment will consist of two phases: a 30-minute stimulation administered 30 minutes before anesthesia induction, and a 30-minute stimulation session once daily on postoperative days 1, 2, and 3. The stimulation intensity will be adjusted in accordance with the maximal level tolerated by each patient. Patients in the sham group will receive electrode attachment but without stimulation.
