Ghosh 2011.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis and combination prophylaxis
Participants	Baseline characteristics Palonosetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 30 Received treatment (n): 30 Analysed (n): 30 Age (mean ± SD, median (IQR), median (range)): 36.33 ± 10 Weight (mean ± SD, median (IQR), median (range)): 57.47 ± 8.25 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 25/5/0/0 Gender (female in %): 90 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (isoflurane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): 59 Use of perioperative opioids (if yes, which?): intraoperative fentanyl 1 µg/kg every 30 minutes, tramadol 100 mg IV Type of surgery: laparoscopic cholecystectomy Palonosetron + dexamethasone Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 30 Received treatment (n): 30 Analysed (n): 30 Age (mean ± SD, median (IQR), median (range)): 35.03 ± 10.15 Weight (mean ± SD, median (IQR), median (range)): 56.67 ± 9.81 BMI (mean ± SD, median (IQR), median (range)): NA ASA I/II/III/IV (n): 25/5/0/0 Gender (female in %): 83 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (isoflurane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): 61.33 Use of perioperative opioids (if yes, which?): intraoperative fentanyl 1 µg/kg every 30 minutes, tramadol 100 mg IV Type of surgery: laparoscopic cholecystectomy Included criteria: ASA I and II, 18 to 60 years of age, weighing 40 to 70 kg, scheduled for elective laparoscopic surgery under general anaesthesia Excluded criteria: pregnant or menstruating, gastrointestinal or renal disease, received cancer chemotherapy within past 4 weeks, emetogenic radiotherapy within past 8 weeks, had experienced nausea or vomiting, had taken antiemetic medication within 24 hours before surgery Pretreatment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear
Interventions	Intervention characteristics Palonosetron Dose: 0.075 mg Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 0% (ondansetron 4 mg) Palonosetron + dexamethasone Dose: palonosetron 0.075 mg, dexamethasone 8 mg Time point of administration: before induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 0% (ondansetron 4 mg)
Outcomes	Vomiting (0 to 24 hours) Outcome type: dichotomous outcome Vomiting (0 to 2 hours) Outcome type: dichotomous outcome Vomiting (2 to 24 hours) Outcome type: dichotomous outcome Complete response (no PONV) in 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: departmental funding only Country: India Setting: Inpatient, single‐centre Author's name: Dr. Anirban Pal Institution: Department of Anesthesiology, Calcutta National Medical College (CNMC), Kolkata, India Email: pal.anirban1@gmail.com Address: 43/6/5 Jheel Road, Kolkata ‐ 700 031, West Bengal, India Language: English Duration of study: NA Trial registry number: NA Study's primary outcome: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "the patients were randomly (computer‐generated numbers inserted into opaque envelope) allocated to two groups P and PD"
Allocation concealment (selection bias)	Unclear risk	Quote: "the patients were randomly (computer‐generated numbers inserted into opaque envelope) allocated to two groups P and PD..." Judgement comment: not stated if envelopes were sequentially numbered and sealed (SNOSE)
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "a consultant anesthesiologist who performed general anesthesia and used the study drug, was unaware of the type of study drug used and did not participate in the study"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "...paracetamol 1 g (100 ml). Patients were asked about nausea, vomiting, retching and any side‐effects, at 2, 6, 24, 48 h by an investigator. The investigator and the patients were blinded to the study drug used. The severity of PONV..."
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): no; (history of PONV/motion sickness, non‐smoker): unclear