Schaff 1978.

Study characteristics
Methods	Design: RCT, parallel two‐arm, single‐centre study Setting: university teaching hospital, Baltimore, MD, USA Recruitment: January 1977 to April 1977 Maximum follow‐up: not reported
Participants	114 participants undergoing cardiac surgery were randomised to one of two groups: Autotransfusion system (Cell salvage/intervention group): N = 63. M:F 41:22. Mean (SD) age 53.6 (10.3) Control group: N = 51. M:F 32:19. Mean (SD) age 53.4 (10.0) Demographic and procedural data were similar between the two groups. No formal statistical comparison was performed.
Interventions	Autotransfusion system (Cell salvage/intervention group): cell salvage group (Sorenson autotransfusion system) received shed mediastinal blood processed by the Sorenson autotransfusion system (ATS). Blood collected in the ATS bags was considered suitable for autotransfusion only if 400 mL or more was collected within 4 hours. If the rate of mediastinal bleeding was slow and 4 hours passed without 400 mL volume being collected, this blood was not reinfused. Shed mediastinal blood was given in preference to stored bank blood when volume replacement was necessary. Control group: control group received only transfusions of stored bank blood. Autotransfusion was not performed.
Outcomes	Outcomes reported: amount of allogeneic blood transfused, total blood and blood component replacement, mediastinal blood loss, haematological variables, adverse events
Notes	Transfusion protocol: if Hct values were below 35% and left ventricular filling was judged to be adequate, whole blood and/or packed red blood cells were infused to restore intravascular volume. With higher haematocrit values and with low left ventricular filling pressures, participants received an infusion of colloid solution or crystalloid solution (Ringer's lactate). 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: Research Center Grant No. HL‐01601 from the National Heart, Lung, and Blood Institute, The Hazel Dell Foundation and Sorenson Research Company. Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Method used to generate allocation sequences was inadequate: randomised by odd or even history numbers
Allocation concealment (selection bias)	High risk	Method used to conceal treatment allocation was inadequate: randomised by odd or even history numbers; could not be concealed
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: "If hematocrit values were below 35 percent and left ventricular filling was judged to be inadequate, whole blood and/or packed red blood cells were infused to restore intravascular volume". Swan‐Ganz catheters were placed to measure pulmonary capillary wedge pressure (PCWP) and cardiac output (CO).
Blinding of participants and personnel (performance bias) Subjective: all other outcomes	High risk	No mention of blinding and unclear definitions for multiple outcomes, subject to variability
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	No mention of blinding and unclear definitions for multiple outcomes, subject to variability
Incomplete outcome data (attrition bias) All outcomes	Low risk	Appears to be ITT for postoperative blood loss and replacement
Selective reporting (reporting bias)	Unclear risk	No trial registration or published protocol is available to compare
Other bias	Low risk	Funding reported (non‐pharmaceutical). No obvious baseline imbalance