This single-center randomized sham-controlled trial will be conducted in cardiothoracic surgery department of the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine in China. A total of 92 eligible participants with pulmonary nodules (size ≥ 8mm) who will undergo VATS will be randomly allocated to a TEAS group and a sham TEAS (STEAS) group in a 1:1 ratio. Daily TEAS/STEAS treatment will be performed starting on 3 days before the VATS and continued for three consecutive days, once per day. The primary outcome will be the minimal clinically important difference of generalized anxiety disorder scale score change between the day before surgery with the baseline. The secondary outcomes include serum concentrations of 5-hydroxytryptamine, norepinephrine and gamma-aminobutyric acid, intraoperative anesthetic consumption, time to postoperative chest tube removal, postoperative pain, length of postoperative hospital stay. The adverse events will be recorded for safety evaluation. All data in the study will be analyzed using the SPSS 21.0 statistical software package.

This single center, randomized, sham-controlled, participant-blinded and assessor-blinded trial will be conducted at the inpatient ward of cardiothoracic surgery department of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine affiliated to Shanghai University of Traditional Chinese Medicine. The trial will commence after ethical approval has been obtained and the protocol has been registered. Patient enrollment started in late June 2021 and is expected to end in March 2023. An estimated 92 participants will be recruited and randomly assigned to receive TEAS or sham TEAS (STEAS) in a l:l ratio using SPSS 21.0 software. During the development of the standard protocol, the Standards for Reporting Interventions in Clinical Trials for Acupuncture (STRICTA) and the SPIRIT reporting guidelines will be followed to explicitly and transparently explain the therapeutic processes involved.

Patients who will undergo VATS for pulmonary nodules will be screened. . Potential subjects will be interviewed preoperatively by the clinical research coordinator to assess whether they meet the inclusion and exclusion criteria. Eligible participants will voluntarily provide written informed consent prior to randomization.

This study will have a single-blind design. The patients are blinded to the group assignment and are told that they might or might not feel a sensation when the TEAS is working. Both acupoint stimulations in the TEAS group and in the STEAS group will be performed by the same acupuncturist who is not involved in the process of data collection. The TEAS instrument is covered with an opaque box for adequate blinding. The randomized numbers were generated with SPSS 21.0 (IBM®SPSS®Statistics, Version 21) software. The random sequence for group classification will be sealed in a confidential envelope. Patients will be randomly allocated into the TEAS group or STEAS group at a ratio of 1:1. Group assignment was exposed from a sealed envelope only by an acupuncturist. Patients will be treated separately to prevent communication. Efficacy evaluation will be conducted blinded to the grouping allocation. The efficacy evaluators and statisticians will be separated and blinded. To test the participant-blinding effects, all participants will be asked to guess whether they had received TEAS or STEAS within 5 minutes after one of the treatment sessions before VATS.

Inclusion criteria

1. Those diagnosed as pulmonary nodules requiring VATS.
2. Age between 18 and 75 years old.
3. 4 ≤ GAD-7 score ≤ 9 and those who have no previous mental illness and have not used anti-anxiety or psychotropic drugs within 2 weeks.
4. Those who have clear consciousness, normal understanding, no expression barriers, can cooperate with treatment and have signed an informed consent.
5. Patients who have not received TEAS treatment in the past.
6. Patients who have not participated or participating in other clinical trials one month before enrollment.

Exclusion criteria

1. Patients with skin infections in local meridian points.
2. Patients with upper or lower limb nerve injury.
3. Patients who had been implanted pacemaker.

Rejection, suspension and dropout criteria

1. Those with serious adverse reactions.
2. Those who presented worsen symptoms or life-threatening illnesses that cannot be continued during treatment.
3. The principal investigator asserts that there are unacceptable risks for serious adverse events during the study.
4. Patients who cannot cooperate to complete the research plan, including language difficulties, infectious diseases and other medical history.
5. Patients quit by themselves.

Reasonable requests for IPD data can be obtained by contacting the investigator.

Within five years of publication of the trial.

Reasonable requests for IPD data can be obtained by contacting the investigator.