Clagett 1999.

Study characteristics
Methods	Design: RCT, parallel two‐arm, multi‐centre study. Each participating hospital was part of a single university teaching hospital. Setting: three sites of a single university teaching hospital, Dallas, TX, USA Recruitment: September 1996 to December 1997 Maximum follow‐up: duration of hospital stay
Participants	100 participants undergoing aortic surgery were randomly allocated to one of two groups: Intraoperative autotransfusion group (Cell salvage/intervention group): N = 50. M:F 41:9. Mean (SD) age 63 (11.0). Mean (SD) weight 77 (15) kg. Control group (Control/no cell salvage group): N = 50. M:F 43:7. Mean (SD) age 65 (9.0). Mean (SD) weight 79 (15) kg. There was a between‐group difference in renal insufficiency, measured by serum creatinine level, pre‐operatively.
Interventions	Intraoperative autotransfusion group (Cell salvage/intervention group): intraoperative autotransfusion group had their blood processed by either a Cell Saver 3 Plus or Cell Saver 5 device. Both systems consist of polyvinyl aspiration tubing with a separate channel for introducing small amounts of heparinised saline solution to anticoagulate aspirated blood, a plastic cardiotomy reservoir with microaggregate filter, a continuous flow, disposable washing bowl driven by a centrifuge, and a transfusion setup that consists of a plastic transfer pack passed to the anaesthesiologist for administration. The maximum allowable amount of IAT‐PRBCs [intraoperative autotransfusion packed red blood cells] administered to a single patient was 1500 mL. Control group (Control/no cell salvage group): control group did not receive autotransfusion.
Outcomes	Primary outcomes: total amount of allogeneic blood transfusion per participant during the period of hospitalisation, and the proportion of participants in whom allogeneic blood was not transfused Secondary outcomes: blood loss, hospital length of stay, intensive care unit (ICU) length of stay, morbidity and mortality
Notes	Transfusion protocol: intraoperative transfusion for haemodynamic instability and/or Hb < 10 g/dL (Hct < 30%), and postoperative transfusion for Hb < 8 g/dL (Hct < 25%), or Hb between 8 and 10 g/dL (Hct, 25% to 30%) for those with compromised cardiopulmonary status. Prospective registration status: the study was published prior to 2010. Ethical approval: the protocol was approved by the University of Texas Southwestern Medical Center Institutional Review Board and the Human Studies Committee of the Dallas Department of Veterans Affairs (VA) Medical Center. 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)	Low risk	Randomised by means of a drawing of sealed envelopes that contained prescriptions for either intraoperative autotransfusion (IAT) or control therapy.
Allocation concealment (selection bias)	Unclear risk	Randomised by means of a drawing of sealed envelopes that contained prescriptions for either IAT or control therapy; not known whether envelopes opaque
Blinding of participants and personnel (performance bias) Objective outcome: mortality	Low risk	Objective outcome (mortality) unlikely to be influenced by blinding
Blinding of participants and personnel (performance bias) Subjective: transfusion protocol	Low risk	Transfusion protocol in place: intraoperative transfusion for haemodynamic instability and/or Hb < 10 g/dL (Hct < 30%), and postoperative transfusion for Hb < 8 g/dL (Hct < 25%), or Hb between 8 and 10 g/dL (Hct, 25% to 30%) for those with compromised cardiopulmonary status.
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	High risk	Unblinded study: high risk for some outcomes (blood loss and wound complication). Authors note that it "is possible that there were sources of bias that may have influenced outcomes. If so, it is likely to have favored the use of IAT. Surgeons and anesthesiologists were accustomed to using IAT during aortic surgery at our institution, and some were initially reluctant to randomize patients. An early concern was that anesthesiologists would be more likely to administer allogeneic blood to control patients simply because the IAT device was absent."
Blinding of outcome assessment (detection bias) Objective outcomes: mortality and transfusions	Low risk	Objective outcome (mortality) unlikely to be influenced by blinding
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Unblinded study: high risk for some outcomes (blood loss and wound complication). Authors note that it "is possible that there were sources of bias that may have influenced outcomes. If so, it is likely to have favored the use of IAT. Surgeons and anesthesiologists were accustomed to using IAT during aortic surgery at our institution, and some were initially reluctant to randomize patients. An early concern was that anesthesiologists would be more likely to administer allogeneic blood to control patients simply because the IAT device was absent."
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants randomised are accounted for in the reported outcomes: 100 enroled, 100 analysed. Unclear if this was total randomised, but suspect so due to the reporting of exclusions.
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Unclear risk	Some baseline imbalance (renal insufficiency), unclear how that may impact outcomes. Funding and conflicts not reported