Ploner 1997.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 3 groups, monoprophylaxis, different routes of administration
Participants	Baseline characteristics Ondansetron (group A) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 40 Received treatment (n): 40 Analysed (n): 40 Age (mean ± SD, median (IQR), median (range)): 41 ± 18 Weight (mean ± SD, median (IQR), median (range)): 62 ± 5 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): 67.5 Non‐smoker (%): NA History of PONV/motion sickness (%): 0/NA Type of general anaesthesia: inhalational anaesthesia (N₂O, isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 138 Use of perioperative opioids (if yes, which?): 600 µg fentanyl Type of surgery: laparoscopic and open gynaecological surgery Ondansetron (group B) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 40 Received treatment (n): 40 Analysed (n): 40 Age (mean ± SD, median (IQR), median (range)): 39 ± 19 Weight (mean ± SD, median (IQR), median (range)): 65 ± 6 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): 62.5 Non‐smoker (%): NA History of PONV/motion sickness (%): 0/NA Type of general anaesthesia: inhalational anaesthesia (N₂O, isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 126 Use of perioperative opioids (if yes, which?): 575 µg fentanyl Type of surgery: laparoscopic and open gynaecological surgery Placebo (group C) Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 40 Received treatment (n): 40 Analysed (n): 40 Age (mean ± SD, median (IQR), median (range)): 37 ± 19 Weight (mean ± SD, median (IQR), median (range)): 59 ± 4 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): NA/NA/0/0 Gender (female in %): 57.5 Non‐smoker (%): NA History of PONV/motion sickness (%): 0/NA Type of general anaesthesia: inhalational anaesthesia (N2O, isoflurane) Duration of anaesthesia or surgery (in min; as mean or median): 156 Use of perioperative opioids (if yes, which?): 625 µg fentanyl Type of surgery: laparoscopic and open gynaecological surgery Included criteria: gynaecological abdominal patients with an expected operation duration of at least 60 minutes, ASA I or II Excluded criteria: younger than 18 or over 75 years of age, ASA III or IV, obese with BMI > 28, history of PONV after general anaesthesia, liver or renal disease, cardiovascular disease, pregnant or given birth in the last 3 months, intake of antiemetic medication in the last 24 hours before operation, feeling of nausea Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids, history of PONV): no; (history of motion sickness, non‐smoker): unclear
Interventions	Intervention characteristics Ondansetron (group A) Dose: 4 mg Time point of administration: ondansetron 10 minutes before initiation of anaesthesia, saline 10 minutes before end of surgery Route of administration: IV Rescue antiemetics (if yes, which?): 5% metoclopramide Ondansetron (group B) Dose: 4 mg Time point of administration: saline 10 minutes before initiation of anaesthesia, ondansetron 10 minutes before end of surgery Route of administration: IV Rescue antiemetics (if yes, which?): 17.5% metoclopramide Placebo (group C) Dose: 2 x 0.9% NaCl Time point of administration: 10 minutes before initiation of anaesthesia and 10 minutes before end of surgery Route of administration: IV Rescue antiemetics (if yes, which?): 42.5% metoclopramide
Outcomes	Adverse events (general notes in the publication, 12 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: NA Country: Italy Setting: inpatient, single‐centre Author's name: Dr. F. Ploner Institution: Abteilung für Anästhesie und allgemeine Intensivmedizin, Landeskrankenhaus Brixen Email: NA Address: Abteilung für Anästhesie und allgemeine Intensivmedizin, Landeskrankenhaus Brixen, Dantestraße 81, I‐39042 Brixen Duration of study: NA Language: German (2 German reviewers) Study's primary outcome: incidence of PONV Trial registry number: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "die Patienten wurden randomisiert in drei Gruppen gleicher Anzahl und gleicher Art" Judgement comment: 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	Quote: "Doppelblindstudie" Judgement comment: insufficient information on blinding ("double‐blinded study")
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: insufficient information on blinding ("double‐blinded study")
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	Unclear risk	Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids, history of PONV): no; (history of motion sickness, non‐smoker): unclear