Tuman 1991.

Methods	RCT Approved by the ethics committee and informed consent obtained Setting: United States of America Funding: unspecified
Participants	80 adult patients undergoing major vascular surgery of the abdominal aorta and lower extremities Exclusion criteria were preoperative coagulopathies or liver disease, receiving anticoagulant or antiplatelet medications and any contraindications to use of an epidural catheter, or any of the standard anaesthetic/analgesic agents employed
Interventions	Treatment group: high lumbar or low thoracic (L3‐T10) tested with 3 mL of 1.5% lidocaine with epinephrine 5 mcg/mL, lidocaine 1.5% during surgery (12 to 20 mL) followed by an infusion with 0.1% bupivacaine and fentanyl 0.001% after surgery for an average duration of 2.40 ± 0.98 postoperative days (n = 40) Control group: no epidural and parenteral and/or oral opioid analgesics as requested for pain relief after surgery (n = 40) General anaesthesia for all participants
Outcomes	Pain: "The average pain scores in the epidural local anaesthetic group on the first three postoperative days were 2.3 ± 2.6, 1.1 ± 1.4, and 0.8 ± 1.0, respectively, as measured on a visual analogue scale from 0 to 10" Length of hospital stay: "The duration of hospital stay after surgical procedures performed under combined general/epidural anaesthesia was 10.7 ± 6.8 days compared with 13.2 ± 11.7 days in those receiving general anaesthesia alone (P = 0.565)"
Notes	Possibly included surgery on lower extremities. Requested aortic abdominal surgery participant data (for another Cochrane review: Guay J, Kopp S. Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery. Cochrane Database of Systematic Reviews 2016, Issue 1. Art. No.: CD005059), but study authors did not reply
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomly assigned", no details
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not mentioned: "The physicians and nurses involved in the care of the patients were unaware of the outcome variables that were being monitored"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned: "Data were collected by a full‐time data manager"
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	High risk	"The study groups are similar in terms of preoperative characteristics, chronic drug therapy, and surgical variables, except for a greater incidence of diabetes mellitus and prior myocardial infarction in the epidural group"