Dalrymple‐Hay 1999.

Methods	Patients undergoing either coronary artery bypass grafting, valve replacement/repair operations or a combination of the two were randomised pre‐operatively into two groups using a binary random number table. Method used to conceal treatment allocation was not described.
Participants	112 patients undergoing cardiac surgery were randomised to one of two groups: Group 1 (Autotransfusion group): n=56; M/F=36/20; mean (sd) age = 67.4 (9.0) years Group 2 (Control group): n=56; M/F=41/15; mean (sd) age = 65.3 (10.5) years
Interventions	Group 1: Autotransfusion group were transfused with washed post‐operative drained blood processed by a Fresenius Continuous Autotransfusion System (C.A.T.S). Group 2: Control group received usual care management without autotransfusion.
Outcomes	Outcomes reported: amount of allogeneic blood transfused, number of patients transfused allogeneic blood, mortality, re‐operation for bleeding, blood loss, coagulopathy, Hb levels.
Notes	Transfusion threshold: patients were transfused allogeneic RBCs intra‐operatively if the haemoglobin level was less than 7.0g/dL. Post‐operatively patients were transfused allogeneic RBCs if the haemoglobin level was less than 10.0g/dL.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk
Allocation concealment (selection bias)	Unclear risk	Method used to conceal treatment allocation was not described.
Blinding (performance bias and detection bias) All outcomes	High risk