Bang 2016.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Placebo Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 50 Received treatment (n): 50 Analysed (n): 50 Age (mean ± SD, median (IQR), median (range)): 45 ± 11 Weight (mean ± SD, median (IQR), median (range)): 59.4 ± 7.9 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 38/12/0/0 Gender (female in %): 100 Non‐smoker (%): 92 History of PONV/motion sickness (%): 50/92 Type of general anaesthesia: TIVA Duration of anaesthesia or surgery (in min; as mean or median): 123 Use of perioperative opioids (if yes, which?): 536.8 µg fentanyl Type of surgery: gynaecological laparoscopic surgery Palonosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 50 Received treatment (n): 50 Analysed (n): 50 Age (mean ± SD, median (IQR), median (range)): 43 ± 8 Weight (mean ± SD, median (IQR), median (range)): 59.8 ± 7.1 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 38/12/0/0 Gender (female in %): 100 Non‐smoker (%): 86 History of PONV/motion sickness (%): 56/86 Type of general anaesthesia: TIVA Duration of anaesthesia or surgery (in min; as mean or median): 126 Use of perioperative opioids (if yes, which?): 540.9 µg fentanyl Type of surgery: gynaecological laparoscopic surgery Included criteria: women 20 to 60 years of age with American Society of Anesthesiologists physical status I or II Excluded criteria: patients who experienced vomiting or retching in the 24‐hour period before surgery; patients who underwent emetogenic radiotherapy within 8 weeks or cancer chemotherapy within 4 weeks before study entry; patients who had received steroids, antiemetics, or psychoactive medications 24 hours before study initiation Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no
Interventions	Intervention characteristics Placebo Dose: saline 1.5 mL Time point of administration: just before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 12% (metoclopramide 10 mg) Palonosetron Dose: 0.075 mg Time point of administration: just before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 4% (metoclopramide 10 mg)
Outcomes	Vomiting (0 to 24 hours) Outcome type: dichotomous outcome Vomiting (0 to 2 hours) Outcome type: dichotomous outcome Vomiting (2 to 6 hours) Outcome type: dichotomous outcome Nausea (0 to 24 hours) Outcome type: dichotomous outcome Complete response (no PONV) in 24 hours Outcome type: dichotomous outcome Subjects with any SAE (0 to 24 hours) Outcome type: dichotomous outcome Headache (0 to 24 hours) Outcome type: dichotomous outcome Adverse events (general notes in the publication, 24 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: there are no financial or other relationships to disclose that might lead to a conflict of interest regarding this article Country: Korea Setting: inpatient, single‐centre Author's name: Soo Kyoung Park Institution: Department of Anesthesiology and Pain Medicine, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Gyeonggi, Korea Email: hardmong@naver.com Address: Department of Anesthesiology and Pain Medicine, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, 7 Keun Jaebong Road, Hwaseong, Gyeonggi, Korea Duration of study: June to October 2015 Language: English Study's primary outcome: the primary outcome was the overall incidence of nausea and vomiting during the first 24 hours after anaesthesia Trial registry number: NCT01478165
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "using a computer‐generated number table"
Allocation concealment (selection bias)	Unclear risk	Quote: "trained nurses, who were not involved in the study, prepared the study drugs before induction of anesthesia, according to directions in an envelope containing the allocation groups" Judgement comment: not stated sequentially numbered, opaque, and sealed envelopes (SNOSE)
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "trained nurses, who were not involved in the study, prepared the study drugs before induction of anesthesia, according to directions in an envelope containing the allocation groups"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "every assessment and interview was performed by doctors blinded to treatment group enrolment"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "one hundred patients were enrolled (50 per group) and all completed the study"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: NCT01478165 (retrospective registration)
Other bias	Low risk	Quote: "patient demographic data, risk factors and operative data were comparable between the two groups (Table 1)" Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no