Methods	Study was conducted between January 1993 and May 1993. Consecutive patients underwent elective or urgent coronary artery bypass surgery. All procedures were performed by the same cardiac surgeon. Method of randomisation and allocation concealment was not described
Participants	75 consecutive patients undergoing coronary artery bypass graft surgery were randomised into one of two groups: Group 1 (Autotransfusion group): n=42; mean (sd) age = 60 (7.0) years Group 2 (Control group): n=33; mean (sd) age = 59 (8.0) years
Interventions	Group 1: Autotransfusion group received autotransfusion of shed mediastinal blood using the cardiotomy reservoir, after the completion of the coronary artery bypass grafting (CABG). As soon as the chest was closed, the mediastinal tubes were attached to the inlet port of the cardiotomy reservoir, which allows the chest tube drainage to pass through a 20 micron filter. The filtered blood was collected in the bottom of the cardiotomy reservoir, ready for reinfusion. The vacuum port was attached to wall suction apparatus and negative pressure was instituted at 20cm H2O. The chest drains were milked every 30 minutes. The collected blood was reinfused using a standard infusion pump. The hourly volume of mediastinal drainage was measured and the infusion pump adjusted to deliver this amount of blood over the next hour. Reinfusion was continued until the drainage was less than or equal to 50ml per hour for two consecutive hours. Group 2: Control group received standard chest drainage.
Outcomes	Outcomes reported: amount of blood collected by the cell saver, amount of blood retransfused from the cell saver, amount of allogeneic blood transfused, number of patients transfused allogeneic blood, complications, wound infection, re-operation for bleeding, hospital length of stay, fever, mortality
Notes	Transfusion threshold: allogeneic packed cells were transfused intra-operatively or postoperatively when the haematocrit fell below 30%
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