Marberg 2010.

Study characteristics
Methods	Design: RCT, parallel two‐arm, single‐centre study Setting: university teaching hospital, Gothenburg, Sweden Recruitment: September 2006 to May 2007 Maximum follow‐up: duration of hospital stay
Participants	80 consecutive participants with stable angina pectoris, scheduled for CABG were randomised to either autotransfusion or no‐autotransfusion of mediastinal shed blood. Autotransfusion group (Cell salvage/intervention group): N = 39. Mean (SD) age 66 (10). M:F 30:9. Mean (SD) BMI 27 (4). No autotransfusion group (Control/no cell salvage group): N = 38. Mean (SD) age 68(8). M:F 29:9. Mean (SD) BMI 28 (3). There was a between‐group difference in left ventricular ejection fraction (LVEF) at baseline.
Interventions	Autotransfusion group (Cell salvage/intervention group): participants received autotransfusion of all mediastinal shed blood in the first 12 hours postoperatively. Cardiotomy suction blood was continuously re‐transfused without cell salvage during CPB. No autotransfusion group (Control/no cell salvage group): participants avoided all autotransfusion (mediastinal shed blood was discarded). Cardiotomy suction blood was continuously re‐transfused without cell salvage during CPB.
Outcomes	Outcomes reported: postoperative bleeding volume during the first 12 postoperative hours, transfusion requirements
Notes	Transfusion protocol: “Transfusion triggers were predefined in the local clinical protocol. RBC transfusions were given when blood haemoglobin level decreased to < 80 g/L. Platelets were transfused in patients with ongoing bleeding > 300 mL/hr and platelet count < 50 x 109/L, or suspected or confirmed platelet dysfunction. Plasma was transfused in patients with ongoing bleeding > 200 mL/hr and signs of impaired coagulation on thrombo‐elastometry. The final decision regarding transfusion was always made by the attending physician.” Prospective registration status: the study was not prospectively registered with a trials registry. Ethical approval: the study was approved by the Regional Research Ethics Committee for Sahlgrenska University Hospital, Gothenberg, Sweden. Language of publication: English Trial funding: the study was supported by the Swedish Heart and Lung Foundation and Sahlgrenska University Hospital Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation sequence method not stated
Allocation concealment (selection bias)	Unclear risk	While the envelopes used were unmarked, it is not described whether allocation concealment was achieved by using opaque envelopes.
Blinding of participants and personnel (performance bias) Objective outcome: mortality	Low risk	Objective outcome (mortality) unlikely to be influenced by blinding
Blinding of participants and personnel (performance bias) Subjective: transfusion protocol	High risk	Authors provide transfusion protocol but state that in all cases, the final decision to transfuse was made by attending physician, which indicates scope for deviation from protocol.
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	High risk	Lack of blinding of participants/personnel during procedure/postoperative care could affect outcomes such as blood loss/reoperation for rebleed (this trigger has not been defined by authors).
Blinding of outcome assessment (detection bias) Objective outcomes: mortality and transfusions	Low risk	Objective outcome (mortality) unlikely to be influenced by blinding
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	Blinding status unclear
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants randomised within the study are accounted for in the outcome data.
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Low risk	No obvious baseline imbalance. Funding reported (no pharmaceutical funding: the study was supported by the Swedish Heart and Lung Foundation and Sahlgrenska University Hospital). Conflicts of interest not reported