Aitken 1992.

Methods	Study design: RCT Study duration: not reported Study follow‐up: 48 h
Participants	Country: UK Setting: single centre Inclusion criteria: undergoing elective upper abdominal surgery Number: treatment group 1 (19); treatment group 2 (23); control group (21) Mean age (years): treatment group 1 (47.2); treatment group 2 (48.6); control group (56.1) Sex (M/F): treatment group 1 (19/10); treatment group 2 (10/13); control group (10/11) Exclusion criteria: respiratory insufficiency hepatic or kidney impairment; abuse of alcohol or drugs
Interventions	Treatment group 1 Ketorolac: 12.5 mg/h IM infusion for 30 min during surgery then 2.5 mg/h for 47.5 h, with normal saline injections every 4 h Treatment group 2 Ketorolac: 10 mg every 4 h IM for 48 h, first dose during surgery Control group Intermittent and continuous infusions of saline to match other groups
Outcomes	Pre‐operative and post‐operative CrCl, urine output, sodium output, potassium output
Notes	Funding Source: Syntex research gave financial assistance and supplied the study drugs
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study was described as randomised, method of randomisation was not reported
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Study described as "double‐blind"; insufficient information to permit judgement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Incomplete outcome data (attrition bias) All outcomes	High risk	67 patients were randomised, of which 63 patients were included in the patient data table. Six patients were withdrawn from the study after 24 or 48 h of treatment due to equipment failure or on patient's request. No data on randomisation of the withdrawn patients. Of remaining 61 patients there is missing data from 15 patients, probably equally distributed amongst the intervention and placebo groups.
Selective reporting (reporting bias)	Low risk	Study protocol matches outcomes presented
Other bias	High risk	A commercial funding source was used for this study