Jackson 1989.

Study characteristics
Methods	Parallel, data recorded until participant discharged
Participants	Cholecystectomy group: PCA 71, control 34 Hysterectomy group: PCA 72, control 151
Interventions	PCA: meperidine. Bolus/lockout/4 h limit: 10 mg/8 min/NR (titration permitted) Control: IM meperidine (with hydroxyzine or promethazine) at physician's discretion ‐ usually 75 mg to 100 mg every 3 to 4 h prn
Outcomes	Pain intensity, opioid consumption, pulmonary complications, vital signs, level of consciousness/sedation, levels of activity, safety, patient preference, LOS, cost‐effectiveness
Source of funding	Not reported
Notes	Study not split by type of surgery for this review as any data presented separately were not usable in analysis 96% of patients in PCA groups preferred PCA to IM therapy, 100% of nurses thought patients pain controlled better with PCA QS = 1 (R = 1, DB = 0, W = 0)
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 explicitly stated, but appears to be unblinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not clear if all participants completed study, methods of imputation not mentioned
Selective reporting (reporting bias)	High risk	Several outcomes described in Methods section (pain intensity, vital signs, sedation, level of consciousness) are not reported in Results section. For some reported outcomes data reported incompletely (e.g., no standard deviations)
Other bias	Low risk	Adequate sample size