Rho 2001‐2.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Control (group 2) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 20 Received treatment (n): NA Analysed (n): 20 Age (mean ± SD, median (IQR), median (range)): 38 ± 7 Weight (mean ± SD, median (IQR), median (range)): 56 ± 8 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): 100 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: TIVA Duration of anaesthesia or surgery (in min; as mean or median): 111 Use of perioperative opioids (if yes, which?): 1 mg butorphanol intraoperative, no postoperative opioids Type of surgery: laparoscopic hysterectomy, ovarian tumour removal Droperidol (group 4) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 20 Received treatment (n): NA Analysed (n): 20 Age (mean ± SD, median (IQR), median (range)): 37 ± 10 Weight (mean ± SD, median (IQR), median (range)): 55 ± 7 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): 100 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: TIVA Duration of anaesthesia or surgery (in min; as mean or median): 105 Use of perioperative opioids (if yes, which?): 1 mg butorphanol intraoperative, no postoperative opioids Type of surgery: laparoscopic hysterectomy, ovarian tumour removal Included criteria: healthy female patients 20 to 60 years of age, scheduled to undergo laparoscopic hysterectomy and ovarian tumour removal, ASA I or II Excluded criteria: history of recurrent respiratory disease, endocrine system/nervous system disease, pregnancy, obesity (> 50% of normal body weight) Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear; (duration of anaesthesia): yes
Interventions	Intervention characteristics Control (group 2) Dose: normal saline Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): NA Droperidol (group 4) Dose: 1 mg Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): NA
Outcomes	Vomiting (3 to 6 hours) Outcome type: dichotomous outcome PONV (0 to 24 hours) Outcome type: dichotomous outcome Complete response (no PONV) in 24 hours Outcome type: dichotomous outcome Headache (0 to 48 hours) Outcome type: dichotomous outcome Sedation/drowsiness (at recovery room, during 30 minutes postoperative, 30 minutes to 1 hour, 1 to 3 hours, 3 to 6 hours, 6 to 24 hours) Outcome type: dichotomous outcome Adverse events (general notes in the publication, 48 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: NA Country: Korea Setting: inpatient, single‐centre Author's name: Shi Youn Rho Institution: Department of Anesthesiology, Chungnam National University Hospital, Daejeon, Korea Email: NA Address: NA Duration of study: April 2000 to July 2000 Language: Korean (Google Translator) Study's primary outcome: NA Trial registry number: NA
Notes	Study with 4 groups split into 2 sub‐studies (Rho 2005‐1, Rho 2005‐2), with 2 groups each due to different anaesthesia regimens (TIVA vs inhalational)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: quote: "randomly assigned". No further information on sequence generation provided
Allocation concealment (selection bias)	Unclear risk	Judgement comment: no statement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: no statement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: quote: "observed by a familiar nurse who was trained for this study" (translated). No information on blinding of outcome assessors provided
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no missing outcome data
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no reference to a study protocol or trial registry number reported
Other bias	High risk	Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear; (duration of anaesthesia): yes