Misra 2005.

Methods	Parallel‐group randomized trial, conducted in India. Study dates not reported.
Participants	123 adults (18 ‐ 52 y) undergoing middle ear surgery. Exclusion: pregnancy, obesity, diabetes mellitus, impaired renal or liver functions; people who had taken H₂ antagonists, antiemetics, or psychoactive medication; or had nausea, retching, or vomiting within 48 h before surgery. 3 participants withdrew because: they required administration of dexamethasone (n = 2), and facial nerve injury (n = 1).
Interventions	Group 1: sham plaster 1 cm x 1 cm patch affixed to P6 acupoint on both forearms 30 min before induction of anaesthesia and normal saline IV at the end of surgery. Plasters removed 6 h after surgery (n = 40). Group 2: capsicum plaster containing capsicum oleoresin 1% w/w 1 cm x 1 cm patch affixed to P6 acupoint on both forearms 30 min before induction of anaesthesia and normal saline IV at the end of surgery. Plasters removed 6 h after surgery (n = 38). Group 3: sham plaster 1 cm x 1 cm patch affixed to P6 acupoint on both forearms 30 min before induction of anaesthesia and ondansetron 4 mg IV at the end of surgery. Plasters removed 6 h after surgery (n = 39).
Outcomes	Nausea (0 ‐ 24 h), vomiting (0 ‐ 24 h), risk of rescue antiemetic drug (0 ‐ 24 h), adverse effects of plaster.
Notes	Nausea (0 ‐ 6 h), vomiting (0 ‐ 6 h), incidence of rescue antiemetic (0 ‐ 6 h) also reported. Rescue antiemetic was ondansetron 4 mg IV for participants with persistent nausea for more than 5 min, 2 or more episodes of vomiting/retching, or at participant's request for PONV treatment. "One patient complained of mild irritation at the site of capsicum plaster application. No other adverse effects attributable to acu‐stimulation or ondansetron were observed". 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	"The subjects were randomly assigned to one of the three groups using a computer‐generated random number table".
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	"Anesthesia was standardized and given by an anesthesiologist blinded to group assignment".
Blinding of outcome assessor (detection bias) All outcomes	Low risk	"The incidence of PONV was evaluated within six hours and 24 hr after transfer to the postoperative unit by a blinded observer".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for withdrawals given. No missing data reported for the 120 participants analysed.
Selective reporting (reporting bias)	Low risk	All expected outcomes reported.
Other bias	Low risk	Baseline characteristics were comparable. "The demographic characteristics of the three groups were similar, as were history of previous PONV and motion sickness".