Shenkman 1999.

Methods	Parallel‐group randomized trial, conducted in United States. Study dates not reported.
Participants	100 children (2 ‐ 12 y) undergoing tonsillectomy. Exclusion: congenital heart disease or significant pulmonary disease, predisposition for emesis or actual emesis in the 24 h before surgery, use of medications with antiemetic effects within the 24 h before surgery, infection over an acupuncture point, need for postoperative intubation for more than 1 h, and severe obstructive sleep apnoea.
Interventions	Group 1: acupressure wristband on P6 acupoints of both wrists applied before premedication. Immediately after induction of anaesthesia, wristbands were removed and acupuncture needles were inserted at P6 acupoint on both wrists, left in place until next day. Needles were secured with a strip of tape (n = 47). Group 2: acupressure wristbands applied to sham point on both arms before premedication. Immediately after induction of anaesthesia, wristbands were removed and acupuncture needles were applied to sham point on both arms, left in place until next day. Needles were secured with a strip of tape (n = 53).
Outcomes	Vomiting (0 ‐ 24 h), risk of rescue antiemetic drug, side effects of acupressure/acupuncture.
Notes	Rescue antiemetic was ondansetron IV if 2 or more emetic episodes occurred. Combination of acupressure and acupuncture treatment effect was not analysed in subgroup analysis (invasive versus noninvasive). Proportion of acupuncture site redness and irritation was similar in both groups. Funding source from National Institutes of Health General Clinical Research Centre (grant number MRR 02172). Acubands provided by Lifestyle Enterprises, New Jersey. Intradermal needles supplied by OMS Medical Supplies, Massachusetts. No details about 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. P6 acupoints and sham points on all patients were covered with opaque adhesive tape.
Blinding of healthcare providers (performance bias) All outcomes	Low risk	"Postanesthesia care unit and ward nurses who assessed and charted postoperative emesis and medication administration were blinded to the group assignment of each patient".
Blinding of outcome assessor (detection bias) All outcomes	Low risk	"Postanesthesia care unit and ward nurses who assessed and charted postoperative emesis and medication administration were blinded to the group assignment of each patient".
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing data reported for 100 participants analysed.
Selective reporting (reporting bias)	Low risk	All expected outcomes reported.
Other bias	Low risk	Baseline characteristics were comparable. "There were no differences between the groups with regard to demographics or previous retching, vomiting, or either (table 2)".