Papaziogas 2001.

Study characteristics
Methods	Randomised, double‐blind. Ketamine IV + ropivacaine SC vs ropivacaine SC
Participants	N = 55, of whom 35 participants in IV ketamine and control treatment arms
Interventions	Pre‐incisional bolus of ketamine 1 mg/kg IV
Outcomes	Pain intensity (VAS, VRS) reported at baseline, at 3, 6, 12, 24 and 48 h postoperatively. Analgesic consumption reported at 48 h postoperatively. Rescue analgesia. Time to first request for analgesia. AEs
Surgery type	Elective laparoscopic cholecystectomy
Group numbers after end of study (treatment/control)	18/17
Age of patient population (treatment/control)	41.3 ± 13.6 47.9 ± 16.7
Notes	Third group received saline IV and saline SC. No mention of sponsorship or funding
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation not described
Allocation concealment (selection bias)	Unclear risk	Allocation concealment method not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding process not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding process not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	4% was withdrawn
Selective reporting (reporting bias)	Low risk	Predefined outcomes reported
Size	High risk	18, 17 and 18 participants per treatment arm