Rayburn 1988.

Study characteristics
Methods	Parallel, 24 h
Participants	PCA 68, control 62 Cesarean section
Interventions	PCA: meperidine. Bolus/lockout/1 h limit: 10 mg/10 min/60 mg Control: IM meperidine 75 mg to 100 mg (based on body weight) every 3 h prn
Outcomes	Pain intensity and relief, sedation, other adverse effects, cost, nurse satisfaction
Source of funding	Not reported
Notes	QS = 2 (R = 1, DB = 0, W = 1)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
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	Low risk	1 participant was accidentally overdosed on PCA and was excluded from analysis
Selective reporting (reporting bias)	Low risk	All outcomes described in Methods section are reported in Results section
Other bias	Unclear risk	Sall sample size