Konishi 1995.

Methods	Parallel RCT Ethics committee: unspecified Informed consents: unspecified Site: New Tokyo Hospital, Matsudo, Japan Setting: university hospital Dates of data collection: October 1993 to March 1994 Funding: unspecified Registration: unspecified
Participants	97 participants: mean age 64 years: sex distribution: not reported Inclusion criteria Heart surgery patients with average age of 64 years Exclusion criteria Not available from the partial translation
Interventions	Intervention Epidural analgesia with butorphanol (N = 31) or morphine (N = 31) Comparator Systemic analgesia (N = 35) Induction and maintenance: low‐dose fentanyl, nitrous oxide, and isoflurane Surgery: mainly CABG with CPB
Outcomes	Relevant to this review Tracheal extubation Haemodynamic variables Others Rescue analgesia Blood gas ICU length of stay
Notes	Correspondence: email sent 16 March 2018; no reply Conflict of interest: not reported DOI: n/a
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote. "divided"; 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 mentioned
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Unclear risk	No failed epidural mentioned Some participants had laparotomy to take the gastroepiploic artery used for coronary grafting