Andrzejowski 1996.

Methods	Parallel‐group randomized trial, conducted in United Kingdom. Study dates not reported.
Participants	36 women undergoing total abdominal hysterectomy. Exclusions: metal or elastoplast allergy, anticoagulant therapy, local skin disease at P6 acupoint or sham point, or chronic treatment with antiemetics.
Interventions	Semipermanent acupuncture needle inserted at P6 acupoint on both wrists 20 min before induction, left in place until second postoperative day (n = 18). Sham semipermanent acupuncture needle inserted in sham point 20 min before induction, left in place until second postoperative day (n = 18).
Outcomes	Nausea (0 ‐ 8 h), vomiting (0 ‐ 8 h), risk of antiemetic rescue drug, side effects.
Notes	Antiemetic rescue was prochlorperazine 12.5 mg IM when necessary. No side effects reported with interventions. No details about funding source or any declarations of interest among authors.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information. "Patients were allocated randomly into one of two groups".
Allocation concealment (selection bias)	Unclear risk	Insufficient information. "This was achieved by concealing the assignment schedule in sealed envelopes which were opened by the investigator just before inserting the needles". Comment: not sure if envelopes were sequentially numbered and opaque.
Blinding of patients (performance bias) All outcomes	Low risk	Assessments were made by the participants, who were blinded to their treatment.
Blinding of healthcare providers (performance bias) All outcomes	Unclear risk	Insufficient information.
Blinding of outcome assessor (detection bias) All outcomes	Low risk	Assessments were made by the participants, who were blinded to their treatment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing data reported for 36 participants randomized.
Selective reporting (reporting bias)	Low risk	All expected outcomes reported.
Other bias	Low risk	Baseline characteristics were comparable. "There was no significant difference between the two groups in age, weight, total morphine consumed, or duration of anaesthesia".