Bush 1997.

Study characteristics
Methods	Design: RCT, parallel 2‐arm, single‐site trial Setting: university teaching hospital, Sacramento CA, USA Recruitment: August 1995 to November 1996 Maximum follow‐up: in‐hospital stay
Participants	99 participants undergoing elective aortic or infrainguinal arterial reconstruction were randomised to 1 of 2 groups: Liberal group: n = 49; M/F = 41/8; mean (SD) age = 64 (11) years Restrictive group: n = 50; M/F = 32/18; mean (SD) age = 66 (10) years
Interventions	Liberal group: had Hb maintained at or > 10.0 g/dL Restrictive group: transfused only when Hb fell to < 9.0 g/dL
Outcomes	Primary endpoints: myocardial ischaemia, myocardial infarction, death during hospitalisation Secondary endpoints: length of ICU stay, hospital stay, graft patency
Notes	Trial registration: none confirmed Trial funding: not reported COI statement by investigators: none reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Sealed envelopes were chosen at random for participant assignment" (Bush 1997 p 144)
Allocation concealment (selection bias)	Low risk	Sealed envelopes were chosen at random for participant assignment
Blinding of participants and personnel (performance bias) Objective outcomes	Low risk	Blinding of personnel for this intervention was not feasible, but in our view, for objective outcomes such as mortality (the primary outcome used within this review), we have graded risk of bias as 'low'
Blinding of outcome assessment (detection bias) Objective measures	Low risk	Blinding of mortality (the primary outcome used within this review) is not relevant, and we graded risk of bias as 'low'
Blinding of outcome assessment (detection bias) Subjective measures	Low risk	No data on subjective outcomes (e.g. function)  Review authors' judgement: low risk of bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcome data appeared to be complete
Selective reporting (reporting bias)	Unclear risk	No reporting bias was apparent, but in the absence of prospective registration or a trial protocol, assessment must remain 'unclear'
Other bias	Low risk	No other biases identified