Kyzer 1995.

Study characteristics
Methods	Parallel, 24 h
Participants	PCA 12, control 11 Gastroplasty (1 participant in each group also had cholecystectomy)
Interventions	PCA: morphine. Bolus/lockout/4 h limit: 2 mg/15 min/NR Control: IM meperidine (converted to morphine equivalents) 50 mg to 100 mg every 3 to 4 h prn
Outcomes	Pain intensity, opioid consumption, sedation, respiratory rate, blood gas levels, LOS, duration of ileus, incidence of pruritus/nausea/vomiting/complications
Source of funding	Not reported
Notes	SAE: wound infections requiring increased length of hospitalization (n), PCA 4 vs control 1 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 explicitly stated, but appears to be unblinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Not explicitly stated, but appears that all participants completed study
Selective reporting (reporting bias)	Unclear risk	All outcomes described in Methods section are reported in Results section. Adverse event outcomes mostly presented only as not significantly different between groups
Other bias	High risk	Very small sample size