Sniadach 1997.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Ondansetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 80 Received treatment (n): 80 Analysed (n): 80 Age (mean ± SD, median (IQR), median (range)): 33 (18 to 49) Weight (mean ± SD, median (IQR), median (range)): 70 (43 to 128) 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 (%): 0/NA Type of general anaesthesia: inhalational anaesthesia (isoflurane or desflurane) Duration of anaesthesia or surgery (in min; as mean or median): 52 Use of perioperative opioids (if yes, which?): 206 µg fentanyl Type of surgery: laparoscopic gynaecological surgery Droperidol Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 80 Received treatment (n): 78 Analysed (n): 76 Age (mean ± SD, median (IQR), median (range)): 32 (19 to 50) Weight (mean ± SD, median (IQR), median (range)): 68 (46 to 110) 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 (%): 0/NA Type of general anaesthesia: inhalational anaesthesia (isoflurane or desflurane) Duration of anaesthesia or surgery (in min; as mean or median): 53 Use of perioperative opioids (if yes, which?): 178 µg fentanyl Type of surgery: laparoscopic gynaecological surgery Included criteria: women undergoing outpatient laparoscopic gynaecological surgery under general anaesthesia, ASA I or II, 18 to 50 years of age, anaesthesia time less than 2 hours Excluded criteria: known hypersensitivity to any antiemetic Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, history of PONV/motion sickness, perioperative opioids): no; (non‐smoker): unclear
Interventions	Intervention characteristics Ondansetron Dose: 4 mg Time point of administration: during induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): "anaesthesiologists were instructed to treat nausea as needed to ensure patient comfort in the PACU" Droperidol Dose: 20 µg/kg Time point of administration: during induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): "anaesthesiologists were instructed to treat nausea as needed to ensure patient comfort in the PACU"
Outcomes	Adverse events (general notes in the publication, 24 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: funded by a grant from Kaiser Permanente of Colorado Country: USA Setting: outpatient, single‐centre Author's name: M. Steve Sniadach Institution: Department of Anesthesiology, Saint Joseph Hospital, Kaiser Permanente Medical Center, Denver, USA Email: NA Address: Department of Anesthesiology, Saint Joseph Hospital, Kaiser Permanente Medical Center, 2045 Franklin St., Denver, CO 80205 Duration of study: NA Language: English Study's primary outcome: NA Trial registry number: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "prospectively randomized to receive either droperidol..." 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	Low risk	Quote: "...mg) during induction of anesthesia. Study medications were prepared by a single pharmacist in identical syringes, with identical volumes, to ensure blind administration by the anesthesiologist and preoperative nurses. No other antiemetics were given"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "...within 3 days after surgery. The first two assessments were made by 1 of a group of 10 PACU nurses blinded to the medication each patient had received, who asked the subjects about..."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "of the original 160 subjects, 2 were excluded from the study because of failure to receive the study medication at induction, and 2 were excluded because they had received an extra intraoperative antiemetic dose. All four excluded patients had been assigned to receive droperidol. Therefore, data from 156 patients were analyzed"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no reference to a study protocol or trial registry number reported
Other bias	Unclear risk	Quote: "...groups. Neither were differences found between groups in variables that could have potentially influenced nausea and sedation outcomes, including average operation time, average anesthesia time, average PACU time, and average fentanyl dose. No difference in group distribution among types of surgery was noted" Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, history of PONV/motion sickness, perioperative opioids): no; (non‐smoker): unclear