Gieron 1993.

Methods	Parallel‐group randomized trial, conducted in Germany. Study dates not reported
Participants	90 women undergoing gynaecological operations (6 ‐ 8 h).
Interventions	Group 1: acupressure was carried out by fastening small metal bullets at the P6 acupoint to each wrist by an elastic bandage on the morning of the operation and left on for 24 h (n = 30). Group 2: sham acupressure carried out by applying elastic bandage to P6 acupoint on the morning of the operation and left on for 24 h (n = 30). Group 3: no treatment (n = 30).
Outcomes	Nausea (0 ‐ 6 h), vomiting (0 ‐ 6 h), risk of rescue antiemetic (metoclopramide).
Notes	No treatment data were excluded from analysis. Also reported separate incidences of nausea and vomiting (0 ‐ 1 h) and (6 ‐ 24 h). No side effects identified in the trial. 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.
Allocation concealment (selection bias)	Unclear risk	Insufficient information.
Blinding of patients (performance bias) All outcomes	Low risk	Authors took adequate steps to make interventions appear similar.
Blinding of healthcare providers (performance bias) All outcomes	Unclear risk	Insufficient information.
Blinding of outcome assessor (detection bias) All outcomes	High risk	The outcome assessor was not blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing data reported for 90 participants analysed.
Selective reporting (reporting bias)	Low risk	All expected outcomes were reported.
Other bias	Low risk	Baseline characteristics were comparable. "The anthropometric data, the duration of surgery and the amount of postoperative analgesia were comparable between the three groups".