Hu 2006.

Methods	RCT Informed consent obtained Setting: China Fundong: departmental resources
Participants	120 patients scheduled for lower abdominal surgery under general anaesthesia Exclusion criteria were reoperation, severe inflammation and immunological disease
Interventions	Treatment group: epidural analgesia (T12‐L1; installed before surgery) with bupivacaine 0.1% and fentanyl 2 mcg/mL through patient‐controlled epidural analgesia: bolus 3 mL, lockout time 10 minutes, basal rate 6 mL/h (n = 40), duration 48 hours Control groups: IM pethidine on request (n = 40) or IV PCA with morphine (n = 40) General anaesthesia for all participants
Outcomes	Pain scores at rest and on coughing (taken as on movement) at 24 and 48 hours
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomly divided", no details
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up. No failed epidural mentioned
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced