Methods	The study was conducted between September 2003 to October 2004. Patients admitted for elective or sub-acute coronary bypass surgery without the use of the cardiopulmonary bypass (CPB) machine were included. If the CPB machine became necessary during the operation the patient was excluded. Patients were randomised to intervention or control by means of sealed opaque envelopes numbered in sequence
Participants	60 patients undergoing ‘off-pump’ coronary artery bypass surgery were randomly allocated to one of two groups: Group 1 (Autotransfusion group): n=30; M//F=11//19; mean (IQR) age = 77 (74-79) years Group 2 (Control group): n=30; M//F=14//16; mean (IQR) age = 76 (70-79) years
Interventions	Group 1: Autortransfusion group (Medtronic Autolog system) received intraoperative autotransfusion. Immediately after surgery the suctioned blood was processed by the cell saver device and autotransfused before the patient was transferred to the intensive care unit (ICU). Group 2: Control group had their intra-operative suctioned blood discarded. NB: The cell saver reservoir with a 40um filter was used in the ICU for mediastinal drained blood collection and for post-operative autotransfusion in both groups. A maximum of 12 hours of post-operative unwashed autotransfusion from the drains was routine practice
Outcomes	Outcomes reported: amount of allogeneic blood transfused, number of patients transfused allogeneic blood, blood loss, Hb levels, adverse events, costs
Notes	Transfusion threshold: patients were transfused allogeneic RBCs if the haematocrit level was less than 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)	High risk	Method used to conceal treatment allocation was inadequate.
Blinding (performance bias and detection bias) All outcomes	High risk