Schönberger 1993.

Study characteristics
Methods	Design: RCT, parallel two‐arm, multicentre study Setting: 3 university teaching hospitals in the Netherlands Recruitment: January 1992 to April 1992 (intervention dates) Maximum follow‐up: duration of hospital stay
Participants	40 participants undergoing elective primary unilateral internal mammary (IMA) artery bypass grafting were randomly assigned to one of two groups: Group 1 (Autotransfusion (AT) group) (Cell salvage/intervention group): N = 20. M:F 15:5. Mean (SD) age 64 (10.7) Group 2 (Control group): N = 20. M:F 15:5. Mean (SD) age 63 (6.3) Demographic and preoperative variables were similar across the two groups at baseline.
Interventions	Group 1 (Autotransfusion (AT) group) (Cell salvage/intervention group): cell salvage group underwent internal mammary artery (IMA) surgery with pre‐bypass removal of autologous blood, reinfusion of the remaining volume in the extracorporeal circuit (ECC) after aortic decannulation, administration of 200 mL aprotinin containing 280 mg of aprotinin (2 million kallikrein inactivator units) added to the pump prime, acceptance of normovolaemic anaemia (Hct > or equal to 25%) and autotransfusion of the shed blood postoperatively. After insertion of the drainage tubes, postoperative shed blood was collected in cardiotomy reservoir. Blood was transferred from the cardiotomy reservoir to a bag via a filter prior to re‐transfusion. Group 2 (Control group): control group participants underwent IMA surgery under the same conditions as Group 1 with the exclusion of autotransfusion (AT). Autotransfusion refers specifically to the re‐transfusion of ‘shed blood’, as per the description in the abstract
Outcomes	Outcomes reported: amount of blood re‐transfused from the cell saver, amount of allogeneic blood transfused, number of participants transfused allogeneic blood, adverse events, re‐exploration for bleeding, blood loss
Notes	Transfusion protocol: allogeneic packed red cells were transfused when the postoperative Hct fell below 25%. Prospective registration status: the study was published prior to 2010. Ethical approval: the study was approved by the medical‐ethical committee of the host institution. Language of publication: English Trial funding: not reported Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method used to generate allocation sequences was not described.
Allocation concealment (selection bias)	Unclear risk	Method used to conceal treatment allocation was unclear.
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	Low risk	Transfusion protocol in place: packed cells were administered when the postoperative haematocrit fell below 25%.
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	Low risk	The blinding status of participants and personnel is unknown. But low risk of bias for remaining outcomes due to well‐defined diagnosis/decision‐making criteria
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	Low risk	The blinding status of participants and personnel is unknown. But low risk of bias for remaining outcomes due to well‐defined diagnosis/decision‐making criteria
Incomplete outcome data (attrition bias) All outcomes	Low risk	All were analysed (no exclusions)
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Unclear risk	No baseline imbalance. Funding or conflicts not reported