Rein 1989.

Methods	Parallel RCT Ethics committee: approved by the ethical committee of the hospital Informed consents: obtained from all participants Site: Trondheim, Norway Setting: university hospital Dates of data collection: unspecified Funding: this study was supported by a grant from the Norwegian Council for Cardiovascular Diseases Registration: unspecified
Participants	16 participants: age: 60.3 years; sex distribution: 16 males Inclusion criteria Male patients Requiring CABG with extracorporeal circulation Exclusion criteria Not reported
Interventions	Intervention Epidural analgesia (N = 8) Comparator Systemic analgesia (N = 8) Premedication: morphine and scopolamine Induction: thiopentone and pancuronium Maintenance: nitrous oxide, diazepam, and fentanyl or epidural analgesia Surgery: CABG with CPB using a bubble oxygenator
Outcomes	Relevant to this review Risk of mortality Haemodynamic variables Others Postoperative haemodynamics
Notes	Correspondence: letter 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: "16 male patients were allocated at random to two groups"; 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	One participant died 9 hours postoperatively and was excluded from final analyses
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Unclear risk	Not in intention‐to‐treat Groups had similar demographic data