Gäbel 2013a.

Study characteristics
Methods	Design: RCT, parallel two‐arm, single‐centre study Setting: university teaching hospital, Gothenburg, Sweden Recruitment: recruitment and study dates not reported Maximum follow‐up: 24 hours postoperatively
Participants	34 participants undergoing elective CABG for stable angina were randomised to one of two groups: Retransfusion group (Cell salvage/intervention group): N = 15. Mean (SD) age 66 years (8). M:F 11:4. Mean (SD) BMI 27 (4). No retransfusion group (Control/no cell salvage group): N = 15. Mean (SD) age 66 years (8). M:F 12:3. Mean (SD) BMI 27 (4). There was between‐group difference in time spent on the Extracorporeal Circuit (ECC).
Interventions	Retransfusion group (Cell salvage/intervention group): all cardiotomy suction blood was collected in a separate closed uncoated cardiotomy reservoir. Participants in intervention group had re‐transfusion of cardiotomy suction blood (no processing) prior to weaning from cardiopulmonary bypass (CPB). No re‐transfusion group (Control/no cell salvage group): all cardiotomy suction blood was collected in a separate closed uncoated cardiotomy reservoir. Participants in the control group were randomised to no re‐transfusion of cardiotomy suction blood prior to weaning from CPB.
Outcomes	Outcomes reported: postoperative bleeding, amount of transfused red cells, amount of transfused plasma, amount of transfused platelets, MACE as defined by myocardial infarction or any other evidence of thrombotic event
Notes	Transfusion protocol: red blood cell transfusions were given when blood haemoglobin levels decreased to < 80 g/L or if the patient had symptomatic anaemia. Prospective Registration Status: the study was not prospectively registered with a trial registry. Ethical approval: the study received ethical approval from the Research Ethics Committee of the Medical Faculty, University of Gothenburg, Gothenburg, Sweden. Language of publication: English Trial funding: Västra Götaland region (ALF/LUA grant 146281 to AJ), Gothenburg Medical Society (4201 to JG) and The Swedish Heart and Lung Foundation (20090488 to AJ) Conflicts of interest: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation methodology not described
Allocation concealment (selection bias)	Unclear risk	Not known whether envelopes are opaque and sealed
Blinding of participants and personnel (performance bias) Objective outcome: mortality	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of participants and personnel (performance bias) Subjective: transfusion protocol	Low risk	Transfusion protocol in place: RBC transfusions were given when blood haemoglobin level decreased to < 80 g/L, or if the patient had symptomatic anaemia.
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	Low risk	All trial personnel other than the research coordinator and perfusionist were blinded to treatment allocation.
Blinding of outcome assessment (detection bias) Objective outcomes: mortality and transfusions	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of outcome assessment (detection bias) Subjective outcomes	Low risk	All trial personnel other than the research coordinator and perfusionist were blinded to treatment allocation.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	N used for analysis is unclear; 4 participants were excluded following randomisation (1 due to pericardial adhesions, 1 due to overseen treatment with clopidogrel, 1 due to < 100 mL cardiotomy suction blood, and 1 due to technical error intraoperatively). A priori sample size calculation deemed that 30 participants were needed for the study, which was still achieved.
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Low risk	Funding reported and no conflicts reported. Baseline imbalance in ECC time present but unlikely to impact outcomes