Hansdottir 2006.

Methods	Parallel RCT Ethics committee: the Human Ethics Committee of the Sahlgrenska Academy, Goteborg University, Goteborg, Sweden, approved the study protocol Informed consents: all participants gave written informed consent Site: Goteberg, Sweden Setting: university hospital Dates of data collection: from 1 April 2002 to 31 December 2003 Funding: support was provided solely from institutional and/or departmental sources Registration: unspecified
Participants	113 participants; mean age: 66.5 years; sex distribution: 37 females and 76 males Inclusion criteria Patients undergoing elective cardiac surgery (CABG, cardiac valve procedures, combined CABG and valve procedures, or the Maze procedure, with or without CABG) Exclusion criteria Contraindications to epidural anaesthesia Abnormal coagulation tests (i.e. partial thromboplastin time > 45 s or prothrombin time (international normalized ratio) > 1.5 or platelet count < 80,000) Recent (1 week) treatment with thrombolytic or potent antiplatelet drugs (streptokinase, alteplase, clopidogrel, abciximab, tirofiban, integrelin) Aspirin treatment was not considered a contraindication to placement of a thoracic epidural catheter
Interventions	Intervention Epidural analgesia (N = 55) Comparator Systemic analgesia (N = 55) Premedication: midazolam Induction and maintenance: propofol, remifentanil, and atracurium Surgery: CABG, valve procedures, or both with CPB using a membrane oxygenator
Outcomes	Relevant to this review Myocardial infarction Risk of atrial fibrillation or atrial flutter Risk of neurological complications: cerebrovascular accident Pain scores Others Sedation scores Lung function Quality recovery score Length of hospital 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)	Low risk	Participants were randomly assigned the day before surgery to 1 of 2 regimens
Allocation concealment (selection bias)	Low risk	Sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	The infusion bag (250 mL) of the patient‐controlled analgesia pump was changed only once during the postoperative treatment period (72 h) by the nursing team, which was neither blinded to treatment nor involved in assessment of patients The decision to allow hospital discharge was made by the surgical team not blinded to treatment
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Atelectasis was defined as new area(s) of lobar or sublobar atelectatic consolidation with an air bronchogram by a radiologist blinded to treatment Evaluation of quality of recovery score, level of mobilization, pain, degree of sedation, lung function, and eligibility for hospital discharge was performed between 1:00 and 3:00 PM each day by either of two investigators. These investigators were blinded to the assigned treatment The blinded investigators were not involved in nursing of the participants Less than 5% of epidural participants revealed by mistake to the blinded observer the presence of the epidural catheter
Incomplete outcome data (attrition bias) All outcomes	Low risk	113 participants were randomized, 110 participants received allocated treatment, and 97 participants were eventually analysed
Selective reporting (reporting bias)	Low risk	All results were reported
Other bias	Unclear risk	Three participants were excluded because of inability to place the epidural catheter. In 1 of these participants, the catheter was positioned intradurally, and another participant did not co‐operate. A malfunctioning epidural catheter was considered in 7 participants after extubation. Three of these participants had the epidural catheter replaced in the ICU, and 4 were treated with intravenous patient‐controlled analgesia with morphine These 7 participants were analysed on an intention‐to‐treat basis Groups had similar demographic data, except for a higher incidence of off‐pump CABG in the epidural group and a longer cardiopulmonary bypass time in the systemic analgesia group