| Methods |
Randomised clinical trial |
| Participants |
Adults participants undergoing cardiac surgery with a CARE score (a score for cardiac surgery participants used to predict morbidity and mortality) of 3 or 4, or participants of advanced age defined as greater than or equal to 80 years
|
| Interventions |
Those on the restrictive transfusion strategy received RBC transfusions if their Hb was 7.0 g/dL or less during cardiopulmonary bypass and 7.5 g/dL or less postoperatively after bypass. Those on the liberal transfusion strategy received RBC transfusions if their Hb concentration was 9.5 g/dL or less during and less than 10 g/dL after bypass. |
| Outcomes |
The primary outcome was enrolment rate and overall adherence to the transfusion strategies. Clinical outcomes were assessed. |
| Notes |
‐ |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
An independent statistician generated the allocation sequence. |
| Allocation concealment (selection bias) |
Low risk |
Opaque sequential sealed envelopes were opened at the start of surgery. |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Clinicians and participants were not blinded. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Blinding for clinical outcomes was not addressed. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Outcome data appeared complete. |
| Selective reporting (reporting bias) |
Low risk |
No reporting bias was apparent. |
| Other bias |
Low risk |
No other biases were apparent. |
