Jokela 1999.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Tropisetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 60 Received treatment (n): 60 Analysed (n): 60 Age (mean ± SD, median (IQR), median (range)): 49 (20 to 78) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 27 (18 to 39) ASA I/II/III/IV (n): 25/27/8/0 Gender (female in %): 100 Non‐smoker (%): 82 History of PONV/motion sickness (%): 32/42 Type of general anaesthesia: inhalational anaesthesia (sevoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 112 Use of perioperative opioids (if yes, which?): 300 µg fentanyl, 27 mg oxycodone Type of surgery: laparoscopic cholecystectomy Droperidol Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 60 Received treatment (n): 60 Analysed (n): 60 Age (mean ± SD, median (IQR), median (range)): 48 (19 to 74) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 26 (19 to 38) ASA I/II/III/IV (n): 33/24/3/0 Gender (female in %): 100 Non‐smoker (%): 72 History of PONV/motion sickness (%): 42/27 Type of general anaesthesia: inhalational anaesthesia (sevoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 106 Use of perioperative opioids (if yes, which?): 300 µg fentanyl, 27 mg oxycodone Type of surgery: laparoscopic cholecystectomy Included criteria: female inpatients scheduled to undergo elective laparoscopic cholecystectomy, over 18 years of age, ASA I to III Excluded criteria: pregnant or breastfeeding, evidence of metabolic disorders, Parkinson's disease, taking medication with antiemetic activity Pretreatment: baseline characteristics (age, BMI, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no
Interventions	Intervention characteristics Tropisetron Dose: 5 mg Time point of administration: at the beginning of surgery Route of administration: IV Rescue antiemetics (if yes, which?): 42% (metoclopramide 10 mg IV) Droperidol Dose: 1.25 mg Time point of administration: at the beginning of surgery Route of administration: IV Rescue antiemetics (if yes, which?): 50% (metoclopramide 10 mg IV)
Outcomes	Vomiting (0 to 24 hours) Outcome type: dichotomous outcome Vomiting (0 to 2 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 Extrapyramidal symptoms (0 to 24 hours) Outcome type: dichotomous outcome Headache (0 to 24 hours) Outcome type: dichotomous outcome Sedation/drowsiness (after 2 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: NA Country: Finland Setting: inpatient, multi‐centre (2) Author's name: Ritva Jokela Institution: Department of Anaesthesiology, Lapland Central Hospital, Rovaniemi, Finland Email: NA Address: Department of Anaesthesiology, Lapland Central Hospital, PB 8041, FIN‐96101 Rovaniemi, Finland Duration of study: October 1997 to May 1998 Language: English Study's primary outcome: incidence of nausea or vomiting Trial registry number: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "the study patients were randomly assigned, at an equal ratio" Judgement comment: no further information on sequence generation provided
Allocation concealment (selection bias)	Low risk	Quote: "the treatment allocation codes were contained in sealed opaque envelopes, and for each consecutive enrolled patient the assisting nurses opened the next envelope in order and prepared the study drug as outlined, but did not participate in the postoperative assessment"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "the treatment allocation codes were contained in sealed opaque envelopes, and for each consecutive enrolled patient the assisting nurses opened the next envelope in order and prepared the study drug as outlined, but did not participate in the postoperative assessment"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "all patients were interviewed on the ward by the authors on the first postoperative day up to 24 hours after surgery" Quote: "the treatment allocation codes were contained in sealed opaque envelopes, and for each consecutive enrolled patient the assisting nurses opened the next envelope in order and prepared the study drug as outlined, but did not participate in the postoperative assessment" Judgement comment: insufficient information on blinding of outcome assessors
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "a total of 120 patients participated in the study: 60 patients received tropisetron 5 mg and 60 received droperidol 1.25 mg. One hundred and fifteen patients underwent scheduled laparoscopic cholecystectomy. Five laparoscopies (4%) were finally converted into laparotomy because of technical difficulties (two in the tropisetron group and three in the droperidol group); however, all these patients were included in the analysis. Forty‐six patients were studied in Lapland Central Hospital and 74 patients in Oulu University Hospital"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no reference to a study protocol or trial registry number reported
Other bias	Low risk	Quote: "there were no significant differences between the groups in the demographic data (Table 1). The duration of anaesthesia and surgery were also similar, as well as the doses of intraoperative fentanyl administered" Judgement comment: baseline characteristics (age, BMI, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, non‐smoker, history of PONV/motion sickness, perioperative opioids): no