Kirov 2011.

Methods	Parallel RCT Ethics committee: study protocol and informed consent form were approved by the Ethics Committee of Northern State Medical University, Arkhangelsk, Russian Federation Informed consents: written informed consent was obtained from every patient Site: Northern State Medical University, Troitsky Avenue 51, Arkhangelsk, 163000, Russian Federation; University of Tromsø, MH‐Breivika, Tromsø, 9038, Norway; and University Hospital of North Norway, Sykehusveien 38, Tromsø, 9038, Norway Setting: university hospital Dates of data collection: from January 2008 to September 2009 Funding: supported by a grant from the Government of Arkhangelsk region, “Young Pomor scientists”, and departmental funds Registration: NCT01384175
Participants	93 participants; for the participants included in the analysis, mean age: 55.6 years; sex distribution: 42 females and 48 males Inclusion criteria ASA III adult patients with coronary artery disease ASA III and scheduled for elective off‐pump coronary artery bypass grafting Exclusion criteria Age < 18 years Severe valve dysfunction Peripheral vascular disease Simultaneous interventions (carotid endarterectomy, aneurysm repair, etc.) Transfer to CPB during surgery
Interventions	Intervention Epidural analgesia as a continuous infusion (N = 31) or as PCEA (N = 31) Comparator Systemic analgesia (N = 31) Premedication: diazepam Induction: fentanyl, propofol, and pipecuronium Maintenance: propofol, fentanyl, and pipecuronium Surgery: off‐pump CABG
Outcomes	Relevant to this review Risk of mortality at 28 days Risk of myocardial infarction (troponin‐T) Risk of atrial fibrillation or atrial flutter (no difference between groups) Tracheal extubation Pain scores Haemodynamic variables Others Sedation scores ICU length of stay Hospital length of stay
Notes	Correspondence: information received from study authors Conflict of interest: study authors declare that they have no competing interests DOI: 10.1186/1471‐2253‐11‐17
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomized to 3 groups, using the envelope method
Allocation concealment (selection bias)	Low risk	Participants were randomized to 3 groups, using the envelope method
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	One participant was withdrawn from analysis in each group due to protocol violation (transfer to CPB)
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	No failed epidural reported Groups well balanced