Kunstyr 2001.

Methods	Parallel RCT Ethics committee: not reported Informed consents: not reported Site: Department of Cardiology at General University Hospital, Medical Faculty of Charles University, Prague, Czech Republic Setting: university hospital Dates of data collection: from autumn 1998 to spring 1999 Funding: unspecified Registration: unspecified
Participants	81 participants; mean age: 61.6 years; sex distribution: 5 females and 76 males Inclusion criteria LVEF > 40% Exclusion criteria Significant preoperative pulmonary or renal dysfunction Scheduled for CABG under CPB
Interventions	Intervention Epidural analgesia (N = 20) Comparator 1 Postoperative analgesia with a mixture of ketamine 400 mg and sufentanil 100 mcg in 50 mL syringe, administered in a continuous infusion; rate of infusion 0.5 mL/h to 3.5 mL/h (N = 20) Comparator 2 Nurse‐administered morphine (N = 21) Comparator 3 IV PCA with morphine (N = 20) Premedication: morphine; atropine, and midazolam Induction: sufentanil, midazolam, and pipecuronium Maintenance: isoflurane, sufentanil, and midazolam Surgery: CABG with CPB
Outcomes	Relevant to this review Risk of pulmonary complications (respiratory depression) Tracheal extubation Pain scores Haemodynamic variables Others Lung function tests Sedation
Notes	Correspondence: letter 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	Randomized; 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Incomplete outcome data (attrition bias) All outcomes	Low risk	Two participants were withdrawn from the study and were excluded from analysis in the "ketamine" group due to diplopia, 2 were excluded due to TEA catheter dislodgement, and 3 for technical PCA pump problems (low battery)
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Not in intention‐to‐treat Groups well balanced