Chan 1995 (laminectomy).

Study characteristics
Methods	Parallel, 48 h
Participants	PCA 24, control 20 (laminectomy)
Interventions	PCA: morphine. Bolus/lockout/4 h limit: 1.5 to 2 mg/5 to 10 min/NR Control: IM morphine 0.15 to 0.2 mg/kg every 4 h prn
Outcomes	Pain relief, satisfaction with analgesia, nursing time spent on each participant, time to ambulation, resumption of activities of daily living, return of bowel function, return of oral feeding, tolerance of oral analgesia, LOS
Source of funding	Abbott Laboratories
Notes	QS = 3 (R = 2, DB = 0, W = 1)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Appears that all participants completed study, but not stated. Imputation methods not described
Selective reporting (reporting bias)	Low risk	All outcomes described in Methods section are reported in Results section
Other bias	High risk	Very small sample size