Harmon 1999.

Methods	Parallel‐group randomized trial, conducted in Ireland. Study dates not reported.
Participants	104 women undergoing laparoscopy and dye investigation. Exclusions: obesity, diabetes mellitus, and previous history of PONV.
Interventions	Acupressure on P6 acupoint of right wrist, applied immediately before induction for 20 min, removed before end of surgery (n = 52). Sham acupressure on non‐acupoint site, applied before induction for 20 min and removed before end of surgery (n = 52).
Outcomes	Nausea (0 ‐ 24 h), vomiting (0 ‐ 24 h), risk of rescue antiemetic drugs.
Notes	Rescue antiemetic was ondansetron 4 mg IV and prochlorperazine 12.5 mg IM. No side effects in either group noted. Some participants did not have outcome data. 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)	Low risk	"Randomization was conducted by computer..".
Allocation concealment (selection bias)	Unclear risk	"...And the code was sealed until arrival of the patient in the operating theatre". Comment: not sure whether envelopes were sequentially numbered and opaque.
Blinding of patients (performance bias) All outcomes	Low risk	"Both patients and nurses were unaware of patient group allocation".
Blinding of healthcare providers (performance bias) All outcomes	Low risk	"Both patients and nurses were unaware of patient group allocation".
Blinding of outcome assessor (detection bias) All outcomes	Low risk	"..An anaesthetist blinded to the therapy registered whether nausea, retching or vomiting had occurred".
Incomplete outcome data (attrition bias) All outcomes	High risk	In acupressure group (n = 52), missing nausea and vomiting data in 8 and 5 participants respectively. In sham group (n = 52), missing nausea and vomiting data in 13 and 5 participants respectively.
Selective reporting (reporting bias)	Low risk	All expected outcomes reported.
Other bias	Low risk	Baseline characteristics were comparable. "The groups were comparable in age, weight and duration of surgical procedure".