Simpson 1994.

Methods	Consecutive patients scheduled to undergo elective primary total joint arthroplasty was entered into a randomised controlled trial. Method of randomisation and allocation concealment was not described.
Participants	24 patients undergoing elective total joint arthroplasty were randomly assigned to one of two groups: Group 1 (Autotransfusion group): n=12; M/F=5/7; mean (range) age = 64.7 (53‐76) years Group 2 (Control group): n=12; M/F=5/7; mean (range) age = 59.6 (41‐76) years
Interventions	Group 1: Autotransfusion group had a Solcotrans drain inserted in the operating room and connected to the collection unit and placed under continuous suction (‐20cmH2O) once wound closure was complete. Collection continued for 6 hours or until the unit was full. At that time, the amount of drainage was noted. If greater than 350mls, the drainage was reinfused and a new Solcotrans unit connected. ACD‐A (citrate‐based anticoagulant) was used in each unit (40mls). If the drainage was greater than 150mls but less than 350mls, the drainage was reinfused and a standard, spring loaded, closed intermittent suction canister was connected. If the drainage was less than 150mls, the drainage was not reinfused and collection continued, either in the Solcotrans canister or a closed suction drain. Group 2: Control group had drains inserted in the operating room that were connected to a standard, closed system, spring loaded, intermittent suction device. NB: Drains for both patient groups were discontinued once drainage was less than 40mls per 8 hour shift.
Outcomes	Outcomes reported: amount of blood collected by the cell saver, average collection times, blood loss, Hb & Hct levels, coagulation variables.
Notes	Transfusion threshold: post‐operative transfusions were given when the haemoglobin level was less than 10.0g/dL or the haematocrit 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)	Unclear risk	Method used to conceal treatment allocation was unclear.
Blinding (performance bias and detection bias) All outcomes	High risk