Corcoran 2017.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis and combination prophylaxis
Participants	Baseline characteristics Granisetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 16 Received treatment (n): NA Analysed (n): 15 (24 hours) Age (mean ± SD, median (IQR), median (range)): 44 (40 to 46) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 27 (21 to 31) ASA I/II/III/IV (n): 11/4/0/0 Gender (female in %): 100 Non‐smoker (%): 93 History of PONV/motion sickness (%): 27/47 Type of general anaesthesia: propofol infusions, intraoperative opioids were administered at the attending anaesthetist’s discretion Duration of anaesthesia or surgery (in min; as mean or median): 135 Use of perioperative opioids (if yes, which?): total intraoperative fentanyl 225 µg, use of other intraoperative opioids (morphine 20%, methadone 0%, nil other 80%), postoperative fentanyl IV and oxycodone 5 mg to 15 mg orally Type of surgery: major laparoscopic surgery Dexamethasone + granisetron Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): 16 Received treatment (n): NA Analysed (n): 16 (24 h) Age (mean ± SD, median (IQR), median (range)): 45 (41 to 48) Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 26 (23 to 35) ASA I/II/III/IV (n): 7/9/0/0 Gender (female in %): 100 Non‐smoker (%): 56 History of PONV/motion sickness (%): 25/25 Type of general anaesthesia: propofol infusions, intraoperative opioids were administered at the attending anaesthetist’s discretion Duration of anaesthesia or surgery (in min; as mean or median): 123 Use of perioperative opioids (if yes, which?): total intraoperative fentanyl 250 µg, use of other intraoperative opioids (morphine 6%, methadone 6%, nil other 88%), postoperative fentanyl IV and oxycodone 5 mg to 15 mg orally Type of surgery: major laparoscopic surgery Included criteria: adult females, ASA I or II, 18 to 60 years of age, undergoing elective major laparoscopic gynaecological surgery expected to require at least 90 minutes of operative time, requiring a hospital stay to include at least the first postoperative night Excluded criteria: currently or recently taking immunosuppressive agents; had known or suspected malignancy, hypertension, or diabetes mellitus; history of peptic ulceration, chronic pain syndrome requiring regular opioid consumption, a predicted requirement for IV patient‐controlled analgesia, or known hypersensitivity to dexamethasone or granisetron Pretreatment: history of PONV/motion sickness
Interventions	Intervention characteristics Granisetron Dose: 1 mg Time point of administration: after induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 13%; NA Dexamethasone + granisetron Dose: dexamethasone 4 mg + granisetron 1 mg Time point of administration: after induction of anaesthesia Route of administration: IV Rescue antiemetics (if yes, which?): 0%; NA
Outcomes	Vomiting (PACU) Outcome type: dichotomous outcome Postoperative wound infection (day two) Outcome type: dichotomous outcome Adverse events (general notes in the publication, 24 hours' observation) Outcome type: general notes on side effects
Identification	Sponsorship source: Royal Perth Hospital (departmental funds); Health Department of Western Australia (Raine Foundation Clinical Practitioner Fellowship to T.C.); University of Western Australia (T.C.). Country: Australia Setting: inpatient, single‐centre Author's name: Tomas Corcoran Institution: Department of Anaesthesia and Pain Medicine, Royal Perth Hospital Email: tomas.corcoran@health.wa.gov.au Address: Royal Perth Hospital, Box X2213 GPO Perth 6847, Western Australia, Australia Duration of study: February 2010 to March 2013 Language: English Study's primary outcome: NA Trial registry number: ACTRN12608000340336
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "patients were randomized before surgery, in a 1:1 ratio, using a computer‐generated random number sequence"
Allocation concealment (selection bias)	Unclear risk	Quote: "and allocated to one of two groups using sealed opaque envelopes" Judgement comment: not stated; "sequentially numbered, opaque, and sealed envelopes" (SNOSE)
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "the study drug was prepared by an observer who was not connected to the study and diluted to a total volume of 4 ml with 0.9% sodium chloride in an unmarked syringe"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "the patient, the patient’s anaesthetist, and all investigators were blinded to the study drug identity"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "of failure to comply with the study protocol, leaving data on 31 patients to be analysed. Two patients in each group did not complete cell count testing at 48 h, and five patients in the Control group and four in the Dexamethasone group did not complete cell count testing at 6 weeks after surgery"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: ACTRN12608000340336 (prospective registration). The prospectively registered primary outcome (T‐ and B‐cell population) was reported in the protocol without any timing of assessment. The study paper included time measurements for the primary outcome at 24 hours, 7 days, and 6 weeks from baseline values. The focus of the study was not PONV, and primary and secondary outcomes were not defined in the study report
Other bias	High risk	Judgement comment: baseline characteristics (age, weight, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids, history of PONV/motion sickness): no; (non‐smoker): yes