Feiner 2015.

Study characteristics
Methods	Design: RCT, parallel three‐arm, single‐centre study Setting: university teaching hospital, San Francisco, CA, USA Recruitment: May 2006 to April 2010 Maximum follow‐up: none reported
Participants	91 participants aged between 16 and 75 years scheduled to undergo elective major spinal surgery with surgical blood loss sufficient to require erythrocyte transfusion were randomised to one of three groups: Group 1 (Cell salvage/intervention group): N = 36. Mean (SD) age 57 (11). M:F 11:25. Mean (SD) BMI 30.2 (7). Group 2 (Control/no cell salvage group): N = 18. Mean (SD) age 62 (8). M:F 2:16. Mean (SD) BMI 28.2 (5.6). Group 3 (Control/no cell salvage group): unwashed stored allogeneic transfusion. N = 23. Mean (SD) age 56 (12). M:F 9:14. Mean (SD) BMI 29.5 (7.1). Some participants required transfusion prior to either the salvaged blood or allogeneic stored blood being ready for transfusion. These participants either received fresh frozen plasma, whole blood, washed or unwashed autologous erythrocytes. 10 of the 91 participants enroled pre‐donated blood. This was used in case transfusion was required prior to cell saved or allogeneic blood being available. There were between‐group differences in age and current tobacco use at baseline.
Interventions	Group 1 (Cell salvage/intervention group): cell salvage group had cell salvage performed intraoperatively using Fresnius‐Kabi Continuous AutoTransfusion System, Germany. Blood was collected from the surgical field, processed and washed prior to autotransfusion. Group 2 (Control/no cell salvage group): washed stored allogeneic transfusion Group 3 (Control/no cell salvage group): unwashed stored allogeneic transfusion Allocation to the above groups dictated the nature of the first transfusion that would be administered to a participant.
Outcomes	Outcomes reported: change in PaO2/FiO2 (partial pressure of oxygen in the arterial blood/fraction of inspired oxygen (P/F)) ratio from before to after transfusion between groups, changes in the ratio of the dead space (Vd) ventilation to tidal volume (Vd/Vt) and PaO2 from before to after transfusion, rate of acute lung injury
Notes	Transfusion protocol: a transfusion protocol is not reported. Transfusion of stored erythrocytes was permitted at the discretion of the anaesthesiologist. Prospective registration status: the study was not prospectively registered with a trial registry. Ethical approval: the study was approved by the institutional review board of the University of California, San Francisco, CA, USA. Language of publication: English Study groups: for the purpose of our review, we considered Group 1 as the cell salvage/intervention group. Groups 2 and 3 were considered the control/no cell salvage group. Trial funding: multiple funding sources reported (Masimo, Inc. (Irvine, California), Bluepoint Medical (Selmsdorf, Germany), Nonin Medical (Plymouth, Minnesota), CAS Medical Systems (Branford, Connecticut), Covidien (Minneapolis, Minnesota), Mespere LifeSciences (Waterloo, Ontario, Canada), Pacific Medico (Tokyo, Japan), Xhale Inc. (Gainesville, Florida), and Anamedical (Tel Aviv, Israel)) Conflicts of interest: potential conflict of interest reported ‐ one author (RBW) consults for several organisations with an interest in red cell transfusion (U.S. Food and Drug Administration (Silver Spring, Maryland)); National Heart, Lung, and Blood Institute/National Institutes of Health (Bethesda, Maryland); U.S. Department of Defense (Frederick, Maryland); and TerumoBCT (Lakewood, Colorado). He has also consulted for Sangart (San Diego, California), OPK Biotech (Cambridge, Massachusetts), HbO2 Therapeutics (Souderton, Pennsylvania), and Octapharma USA (Hoboken, New Jersey).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated, sealed, opaque envelopes produced by the blinded study statistician
Allocation concealment (selection bias)	Low risk	Computer‐generated, sealed, opaque envelopes produced by the blinded study statistician
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	High risk	No transfusion protocol in place: transfusion of stored erythrocytes was permitted at the discretion of the anaesthesiologist
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	High risk	No other clinical decisions were dictated by the research protocol
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	Unclear risk	Impact of trial protocols and status of outcome assessors unknown for outcomes relevant to this review as these aren't reported. This needs to be updated should these be reported subsequently
Incomplete outcome data (attrition bias) All outcomes	High risk	Per‐protocol analysis performed: a substantial number of participants received an intervention different to the one assigned at randomisation. Following randomisation, study groups were amended to account for a proportion of participants who required transfusion prior to either the cell saved or allogeneic blood being ready for transfusion (N = 14). As a result, analysis was unable to account for the 91 participants randomised to the initial three groups and the statistical analysis plan was changed from an ITT model to a per‐protocol model.
Selective reporting (reporting bias)	High risk	A priori decisions stated in text are not supported by a published protocol. The initial trial was designed to test acute normovolaemic haemodilution. However, study authors report that due to a change in clinical practice, this was changed following study commencement to test intraoperative cell salvage versus allogeneic transfusion.
Other bias	Unclear risk	Funding reported (non‐pharma), conflicts declared (related biotech companies and non‐commercial organisations). Some baseline imbalance (age) according to as‐treated population, unclear of the impact of this. No information on baseline imbalance according to initial randomisation