Koopman‐van Gemert 1993b.

Study characteristics
Methods	Design: RCT, parallel two‐arm, single centre study Setting: specialist orthopaedic hospital, Nijmegen, the Netherlands Recruitment: recruitment and study dates not reported Maximum follow‐up: perioperative
Participants	60 patients undergoing total hip arthroplasty or dorsal lumbo‐sacral fusion surgery were randomised to one of two groups: Group 1 (Perioperative autotransfusion group) (Cell salvage/intervention group): N = 30. M:F 6:23. Mean (SD) age 51 (18) Group 2 (Homologous transfusion only) (Control/no cell salvage group): N = 30. M:F 7:23. Mean (SD) age 53 (18) There were no between‐group differences at baseline with regard to demographic data or preoperative variables.
Interventions	Group 1 (Perioperative autotransfusion group) (Cell salvage/intervention group): the cell salvage group received perioperative autotransfusion by means of the Haemonetics Haemolite‐2 system. The blood shed intraoperatively and during the first six postoperative 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 µm blood filter. Blood cultures were taken before re‐transfusion to the patient. Group 2 (Homologous transfusion only)(Control/no cell salvage group): the 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 participants transfused allogeneic blood, adverse events, blood loss
Notes	Transfusion protocol: allogeneic packed red cells were transfused to maintain an Hct at 30%. Prospective registration status: the study was published prior to 2010. Ethical approval: it is not clear whether the study was approved by an ethics committee or institutional review board. Language of publication: English Trial funding: not reported Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	"Each was alternatingly allocated to one of two groups in the evening before surgery"
Allocation concealment (selection bias)	High risk	Based on the method of randomisation, group allocation is unlikely to be concealed: "Each was alternatingly allocated to one of two groups in the evening before surgery"
Blinding of participants and personnel (performance bias) Objective outcome: mortality	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of participants and personnel (performance bias) Subjective: transfusion protocol	Low risk	Transfusion protocol in place: "homologous packed cells were transfused to maintain their haematocrit at 0.30 l/l (if needed)."
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	Low risk	No mention of blinding but clear description of how blood loss was calculated
Blinding of outcome assessment (detection bias) Objective outcomes: mortality and transfusions	Low risk	No objective outcomes reported (mortality unlikely to be affected by blinding if reported in future publications)
Blinding of outcome assessment (detection bias) Subjective outcomes	Low risk	No mention of blinding but clear description of how blood loss was calculated
Incomplete outcome data (attrition bias) All outcomes	Low risk	One participant was excluded from Group 1 because insufficient information was available. Quote from section 5.1 (Koopman 1993a): "lf definite errors have and can be as occurred, identified such, the results are excluded from the calculations. This will be mentioned in the text and/or tables. The data remaining are then reexamined without these suspect resulls [sic]. All extreme data for which no reason can be found for exclusion are included in the final analysis."
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Unclear risk	No baseline imbalance noted. Funding and conflicts not reported