Methods	A prospective, randomised study evaluated the effect of autotransfusion of shed blood on the reduction and avoidance of donor blood requirements in patients undergoing internal mammary artery bypass (IMA) surgery and treatment with low-dose aprotinin (2 million KIU). Method of randomisation and allocation concealment was not described
Participants	40 patients undergoing elective primary unilateral internal mammary (IMA) artery bypass grafting were randomly assigned to one of two groups: Group 1 (Autotransfusion group): n=20; M//F=15//5; mean (sd) age = 64 (10.7) years Group 2 (Control group): n=20; M//F=15//5; mean (sd) age = 63 (6.3) years
Interventions	Group 1: Autotransfusion 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 200mls aprotinin containing 280mg of aprotinin (2 million kallikrein inactivator units) added to the pump prime, acceptance of normovolemic anaemia (Hct greater than or equal to 25%) and autotransfusion of the shed blood post-operatively. Group 2: Control group patients underwent IMA surgery under the same conditions as Group 1 with the exclusion of autotransfusion (AT).
Outcomes	Outcomes reported: amount of blood re-transfused from the cell saver, amount of allogeneic blood transfused, number of patients transfused allogeneic blood, adverse events, re-exploration for bleeding, blood loss
Notes	Transfusion threshold: allogeneic packed red cells were transfused when the post-operative Hct fell below 25%
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 (performance bias and detection bias) All outcomes	High risk