Koopman 1993b.

Methods	Patients undergoing total hip arthroplasty or dorsal lumbo‐sacral spinal fusion (implantation of a H‐frame) were entered into this randomised study. Each patient was allocated on an alternating basis to one of two groups. The method of randomisation was not described.
Participants	60 patients undergoing total hip arthroplasty or dorsal lumbo‐sacral fusion surgery were randomised to one of two groups: Group 1 (Autotransfusion group): n=30; M/F=6/23; mean (sd) age = 51 (18) years Group 2 (Control group): n=30; M/F=7/23; mean (sd) age = 53 (18) years
Interventions	Group 1: Autotransfusion group received peri‐operative autotransfusion by means of the Haemonetics Haemolite‐2 system. The blood shed intra‐operatively and during the first six post‐operative hours was collected and heparinised. The blood was processed in the Haemolite‐2 by personnel of the Intensive Care Unit (ICU). The erythrocyte suspension produced was transfused to the patient within 4 hours after collection through a 40 micron blood filter. Blood cultures were taken before re‐transfusion to the patient. Group 2: Control group did not receive autotransfusion.
Outcomes	Outcomes reported: amount of blood collected by the cell saver, amount of blood re‐transfused from the cell saver, amount of allogeneic blood transfused, number of patients transfused allogeneic blood, adverse events, blood loss, Hb & Hct levels.
Notes	Transfusion threshold: allogeneic packed cells were transfused to maintain an Hct at 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