El‐Baz 1987.

Methods	Parallel RCT Ethics committee: not reported Informed consents: not reported Site: Chicago, IL, USA Setting: university hospital Dates of data collection: not reported Funding: unspecified Registration: unspecified
Participants	60 participants: mean age: 59 years; sex distribution: not reported Inclusion criteria Patients, aged 34 to 76 years After CABG (1 to 4 grafts) Exclusion criteria Not reported
Interventions	Intervention Epidural analgesia (N = 30) Comparator Systemic analgesia (N = 30) Induction: thiopental and succinylcholine Maintenance: nitrous oxide, halothane, and pancuronium Surgery: CABG with CPB
Outcomes	Relevant to this review Risk of mortality Pain scores Haemodynamic variables Others Rescue analgesia Respiratory function Stress markers
Notes	Correspondence: email sent 16 March 2018; no reply Conflict of interest: none reported DOI: n/a
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote. "patients were randomly divided into two equal groups of 30 patients"; no details provided
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
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	Low risk	No failed epidural mentioned Groups had similar demographic characteristics