Fukami 2009.

Study characteristics
Methods	Study design: randomized controlled trial Study grouping: 2 groups, monoprophylaxis
Participants	Baseline characteristics Dexamethasone Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 40 Age (mean ± SD, median (IQR), median (range)): 58 ± 15 Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 24.4 ± 4.5 ASA I/II/III/IV (n): 37/2/1/0 Gender (female in %): 42.5 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (sevoflurane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): 130 Use of perioperative opioids (if yes, which?): 0.1 mg fentanyl at induction Type of surgery: laparoscopic cholecystectomy Placebo Assessed for eligibility (n): ‐ Enrolled (n): ‐ Randomized (n): NA Received treatment (n): NA Analysed (n): 40 Age (mean ± SD, median (IQR), median (range)): 56 ± 14 Weight (mean ± SD, median (IQR), median (range)): NA BMI (mean ± SD, median (IQR), median (range)): 24.7 ± 3.4 ASA I/II/III/IV (n): 35/4/1/0 Gender (female in %): 37.5 Non‐smoker (%): NA History of PONV/motion sickness (%): NA Type of general anaesthesia: inhalational anaesthesia (sevoflurane, N₂O) Duration of anaesthesia or surgery (in min; as mean or median): 130 Use of perioperative opioids (if yes, which?): 0.1 mg fentanyl at induction Type of surgery: laparoscopic cholecystectomy Included criteria: undergoing laparoscopic cholecystectomy Excluded criteria: ASA IV, older than 80 years of age, pregnancy, treatment with steroids, severe diabetes mellitus (HbA1c > 8.5%), use of opioids or tranquilizers less than 1 week before LC, history of alcohol or drug abuse, preoperative diagnosis of gallbladder carcinoma, acute pancreatitis, emergency operation, conversion from LC to an open procedure Pretreatment: baseline characteristics (age, BMI, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear
Interventions	Intervention characteristics Dexamethasone Dose: 8 mg Time point of administration: 90 minutes before skin incision Route of administration: IV Rescue antiemetics (if yes, which?): metoclopramide 10 mg IV Placebo Dose: saline Time point of administration: 90 minutes before skin incision Route of administration: IV Rescue antiemetics (if yes, which?): metoclopramide 10 mg IV
Outcomes	Postoperative wound infection (postoperative complications were recorded during hospitalization, and patients were followed up at least once after discharge) 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: Japan Setting: inpatient, single‐centre Author's name: Y. Fukami Institution: Department of Surgery, Shizuoka Saiseikai General Hospital, Shizuoka 422‐8527, Japan Email: yasuyuki490225@yahoo.co.jp Address: Department of Surgery, Shizuoka Saiseikai General Hospital, Shizuoka 422‐8527, Japan Duration of study: January 2006 to May 2008 Language: English Study's primary outcome: incidence of nausea and vomiting Trial registry number: NA
Notes	None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...using an equal number of blind envelopes" Judgement comment: insufficient information on sequence generation provided
Allocation concealment (selection bias)	Unclear risk	Quote: "...using an equal number of blind envelopes" Judgement comment: not stated; "sequentially numbered, opaque, sealed envelopes" (SNOSE)
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: insufficient information on blinding ("double‐blind")
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: insufficient information on blinding ("double‐blind")
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "eighteen patients were excluded from the study, because of age more than 80 years (n = 8), lack of consent (n = 2), bile duct injury (n = 1), acute pancreatitis (n = 1) and conversion from LC to an open procedure (n = 6; 6%). A total of 80 LC patients were enrolled (Fig. 1), 40 being randomized to intravenous dexamethasone (8 mg) and 40 to placebo"
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no reference to a study protocol or trial registry number reported
Other bias	Unclear risk	Quote: "...the hospital for 3 days. There were no significant differences between the two groups with regard to mean age, gender, BMI, preoperative CRP level, ASA score, or anesthesia and operation times (Tables 1, 2). Seven patients..." Judgement comment: baseline characteristics (age, BMI, ASA): no. Potential effect modifiers (gender, duration of anaesthesia, perioperative opioids): no; (history of PONV/motion sickness, non‐smoker): unclear