The goal of this clinical trial is to evaluate the effects of transcutaneous electrical acupoint stimulation (TEAS) combined with triple antiemetics for postoperative nausea and vomiting (PONV) in high-risk patients.

The primary question it seeks to answer is:

Does TEAS combined with triple antiemetics further reduce the incidence of PONV in high-risk subjects? Researchers will compare active TEAS with sham stimulation to determine whether the addition of TEAS to dexamethasone, palonosetron, and droperidol lowers the PONV rate beyond that achieved by the triple-drug prophylaxis alone.

780 female patients, aged between 18 to 65 y, who are scheduled for elective laparoscopic surgery requiring general anesthesia, will be randomly allocated to acustimulation group (Group TEAS), or the control group.

In Group TEAS, a surface electrode will be applied to the P6 and L14 acupoint 30 min before induction. An operator will set electric stimulating current at 1mA with frequency at 2 Hz, and gradually increased the current intensity to a little below discomfort threshold. The stimulation will be maintained until the patient is discharged from the operation. In the control group the same protocol was applied for percutaneous acupoint electrical stimulation, initiated before anesthesia induction with the minimum perceptible current (MPC) and terminated after 1 minute.

A standardized anesthetic protocol will be followed. In all groups, dexamethasone 5mg and palonosetron 0.25mg i.v. will be given after induction, and droperidol 1.25 mg i.v. will be given during the abdominal closure. After surgery, metoclopramide 10mg i.v. will be administered as a rescue therapy to any patient who experiences an episode of moderate or severe nausea, an episode of vomiting, and requests rescue medication.

The patients shall be unaware of the group assignments. An anesthesiologist, who are trained for the study and blinded to the randomization, will collect the data.

Inclusion Criteria:

• Women scheduled for laparoscopic surgery ；
• Aged 18-65 years；
• ASA Class I-III；
• Apfel score ≥ 3 (female sex, non-smoker, history of PONV and/or motion sickness).

Exclusion Criteria:

• Patients with a history of allergy to the investigational drug or contraindications；
• Long-QT syndrome ；
• Pregnancy, lactation, or menstruation ；
• Current smoker；
• Nausea/vomiting or use of antiemetics, opioids, or systemic corticosteroids within 24 h before surgery；
• Requirement for post-operative sedation and mechanical ventilation ；
• Severe renal or hepatic impairment ；
• Psychiatric or neurological disorder ；
• Vertebrobasilar insufficiency；
• Vestibular disease；
• Language or communication barrier ；
• Skin lesion or infection at the acupoint stimulation site ；
• Upper-limb nerve injury ；
• Implanted cardiac pacemaker or defibrillator ；
• Participation in another clinical trial within the past 4 weeks.

Both acupoint stimulation and placebo treatment will be administered by the same investigator, who will take no part in anesthesia management or data collection. To maintain blinding, an opaque drape will be placed over the TEAS unit in both groups. All participants will be informed that they may or may not feel a tingling sensation at the wrists while the device is operating. Follow-up and data collection will be performed by a separate investigator who is uninvolved in routine anesthesia care and blinded to group allocation.