Nilsson 2015.

Methods	Parallel‐group randomized trial, conducted in Sweden.
Participants	120 adults undergoing elective infratentorial or supratentorial craniotomy from November 2011 to June 2013. Exclusion: mental impairment or communication problems and use of antiemetics within 12 h before surgery.
Interventions	Group 1: SeaBand acupressure wristband with plastic button was applied on wrist P6 acupoint (marked by neurosurgical ward nursing staff) on wrist that did not have an intra‐arterial catheter at the end of surgery by a nurse anaesthetist (n = 52). Duration of acupressure wristband application was 48 h. Group 2: Sham SeaBand acupressure wristband without plastic button was applied on wrist P6 acupoint (marked by neurosurgical ward nursing staff) on wrist that did not have an intra‐arterial catheter at the end of surgery by a nurse anaesthetist (n = 60). Duration of sham acupressure wristband application was 48 h. Prophylactic IV ondansetron 4 mg was given at the end of surgery to both groups.
Outcomes	Nausea (0 ‐ 48 h), vomiting (0 ‐ 48 h), rescue antiemetic (0 ‐ 48 h), adverse effects related to wristbands.
Notes	Authors reported median times, not incidence, that rescue antiemetic (IV ondansetron 1 ‐ 4 mg or droperidol 0.625 ‐ 1.25 mg, or both) were used (0 ‐ 48 h) for each group. No significant difference in proportion of participants requiring antiemetics between groups. Power calculation done. The side effects (swelling, bruises, paraesthesia or pain) were equally distributed between P6 acupressure group (n = 7) and sham group (n = 7). Study was supported by the hospitals research foundation. Active and sham wristbands were partly provided by the manufacturer. Authors declared no conflicts of interests.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Patients were "randomly assigned to either the PC6 acupressure group or the sham group using a computer‐generated random number table."
Allocation concealment (selection bias)	Low risk	Sealed envelopes, prepared by persons not involved in study, contained information about wristband placement and presumably group allocation.
Blinding of patients (performance bias) All outcomes	Low risk	"Both the PC6 acupressure bands and the sham bands were covered with a bandage to ensure blinding to the patient and outcome assessor."
Blinding of healthcare providers (performance bias) All outcomes	Unclear risk	Insufficient information.
Blinding of outcome assessor (detection bias) All outcomes	Low risk	"Both the PC6 acupressure bands and the sham bands were covered with a bandage to ensure blinding to the patient and outcome assessor."
Incomplete outcome data (attrition bias) All outcomes	Low risk	120 randomized but 95 in final analysis (43 in PC6 acupressure group and 52 in sham group). Reasons for withdrawals were described. "There was no difference between the groups in excluded patients (P = 0.406)."
Selective reporting (reporting bias)	Low risk	All expected outcomes reported.
Other bias	Low risk	"The 2 groups were comparable with respect to medical and demographic characteristics, anesthesia, surgical techniques, risk factors for PONV, and postoperatively administered opioids."