Methods	A prospective, randomised study was performed in a New Delhi tertiary care hospital involving consecutive patients undergoing elective cardiac valve surgery using cardiopulmonary bypass. Method of randomisation and allocation concealment were not described
Participants	150 consecutive patients undergoing elective valve surgery using cardiopulmonary bypass were randomly allocated to one of three groups: Group 1 (Autotransfusion + ANH group): n=50; M//F=35//15; mean (sd) age = 29.1 (11.8) years Group 2 (ANH group): n=50; M//F=25//25; mean (sd) age = 28.1 (9.2) years Group 3 (Control group): n=50; M//F=15//35; mean (sd) age = 26.1 (9.3) years ANH = acute normovolaemic haemodilution.
Interventions	Group 1: Autotransfusion + ANH group received autologous fresh blood donated before bypass, and both cell saver and membrane oxygenator were used. Autologous blood was removed by a central venous catheter after induction of anaesthesia and collected in citrate phosphate preservative at room temperature for subsequent transfusion. Blood volume was maintained with a simultaneous infusion of Ringer’s lactate solution. A Dideco, Shiley cell saver system was used to collect all blood at the operation site. This system heparinises, washes, and centrifuges the blood to produce a red cell concentrate for transfusion. At the conclusion of CPB, all the blood remaining in the oxygenator was also processed by the cell saver in preparation for subsequent transfusion. A “Maxima” membrane oxygenator was used for this group. Group 2: ANH group were reinfused with autologous blood only. Blood was withdrawn as in Group 1 patients and was stored for subsequent transfusion. Group 3: Control group underwent routine management, using a Bentley bubble oxygenator without specific blood conservation techniques. NB: In Groups 2 and 3, the blood remaining in the oxygenator at the termination of CPB was returned to the patient before decannulation, or collected in a bag for immediate use to provide optimum filling pressures and haemodynamic stability in the post-bypass period
Outcomes	Outcomes reported: amount of allogeneic blood transfused, number of patients transfused allogeneic blood, adverse events, re-exploration for bleeding, blood loss, Hct levels
Notes	Transfusion threshold: bank blood (whole blood) was used in all groups if the haematocrit was less than 25%
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)	Unclear risk	Method used to conceal treatment allocation was unclear.
Blinding (performance bias and detection bias) All outcomes	High risk