Methods	Randomised trial to study the quality and effect of blood produced by the cell saver compared with allogeneic blood in primary total hip arthroplasty
Participants	40 patients undergoing primary total hip arthroplasty were randomly allocated to one of two groups: Group 1 (Autotransfusion group): n=20; M//F=9//11; mean (range) age = 68 (59-89) years Group 2 (Control group): n=20; M//F=8//12; mean (range) age = 74 (48-89) years
Interventions	Group 1: Autotransfusion group received autologous blood processed intraoperatively by a cell saver device (Electromedic Autotrans AT1000 autotransfusion system). Blood was retrieved from the operative field with a double lumen suction catheter. The blood was immediately anticoagulated with sodium citrate. Larger debris was removed by a 240um filter in the cardiotomy reservoir. The filtered blood was pumped into a bowl centrifuge and washed with 1500mls of saline. The supernatant was discarded. The erythrocyte concentrate was pumped into a reinfusion bag and then reinfused into the patient. Group 2: Control group received allogeneic blood and no autotransfusion. NB: Thromboprophylaxis was given to all patients using dextran 70, 6% in saline (Macrodex) 500mls during the operation, another 500mls during the remainder of the operation day, and 500mls on post-operative days 1,3 and 5
Outcomes	Outcomes reported: amount of allogeneic units transfused, number of patients receiving allogeneic blood, complications, blood loss, haematological variables
Notes	Transfusion threshold: a transfusion of allogeneic blood was given if the haemoglobin was less than 8.5g/dL or if there were symptoms of anaemia
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