Lewis 1991.

Methods	Parallel‐group randomized trial, conducted in United States. Study dates not reported.
Participants	66 children undergoing strabismus correction surgery. Excluded: children with anatomical or neurological abnormalities of the upper limbs. 2 children lost to follow‐up.
Interventions	Group 1: acupressure wristbands placed on P6 acupoints 1 h before surgery and worn until discharge from hospital (n = 33). Group 2: sham acupressure wristbands without studs placed on P6 acupoints 1 h before surgery and worn until discharge from hospital (n = 33).
Outcomes	Vomiting (0 ‐ 24 h), risk of rescue antiemetic drug, side effects.
Notes	Both types of wristbands were identical unless turned inside out. Rescue antiemetic was droperidol 0.02 mg/kg IV for vomiting. No side effects reported. 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	Low risk	The anaesthetic staff were blinded.
Blinding of outcome assessor (detection bias) All outcomes	Low risk	"A second blinded investigator recorded all other perioperative data, including the incidence of postoperative nausea and vomiting in the recovery areas".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Two participants in acupressure group had incomplete data. Comment: unlikely to have a clinically relevant impact on summary estimate.
Selective reporting (reporting bias)	High risk	Although nausea was an outcome collected in the Methods section it was not reported in the Results because nausea may be difficult to assess in children.
Other bias	Low risk	Baseline characteristics were comparable. "There were no significant differences between the two groups in their patient characteristics".