Lak 2010.

Study characteristics
Methods	Randomised, double‐blind, placebo control
Participants	N = 60, 12% women
Interventions	Ketamine 0.5 mg/kg bolus IV postoperatively + IV infusion 2 µg/kg/min for 24 h, then 1 µg/kg/min the following 24 h
Outcomes	Pain intensity (VAS and face pain scale) reported hourly during the first 4 h, then at 8, 12, 24 and 48 h postoperatively. Analgesic consumption reported at 48 h postoperatively. AEs
Surgery type	Nephrectomy
Group numbers after end of study (treatment/control)	25/25
Age of patient population (treatment/control)	27.3 ± 5.5 27.9 ± 3.9
Notes	No mention of sponsorship or funding
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was assigned to patients of the two groups according to random numbers table"
Allocation concealment (selection bias)	Unclear risk	Allocation concealment method not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Described as "double blind" but not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding process not described
Incomplete outcome data (attrition bias) All outcomes	High risk	20% was withdrawn
Selective reporting (reporting bias)	High risk	Pain outcome not reported using predefined pain scale (face pain scale)
Size	High risk	25 participants per treatment arm