| Methods |
Randomised clinical trial |
| Participants |
ICU participants aged ≥ 55 years, Hg < 9 g/dL, mechanical ventilation for ≥ 96 hours, and were expected to require ≥ 24 hours of further mechanical ventilation when assessed
|
| Interventions |
The restrictive transfusion group received transfusion with haemoglobin≤ 7.0g/dL and a target Hb concentration of 7.1 g/dL to 9.0g/dL, and the liberal transfusion group received transfusions with haemoglobin ≤ 9.0 g/dL and a target of 9.1 g/dL to 11.0 g/dL during intervention. |
| Outcomes |
The primary feasibility outcome was the difference in mean Hb among groups. Clinical outcomes were assessed. |
| Notes |
‐ |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Minimisation by centre and the presence of IHD, including a random element, was used. |
| Allocation concealment (selection bias) |
Low risk |
The trial used telephone randomisation. |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Clinicians were not blinded. Most surviving participants stated that they were unaware of group allocation at 180 days (restrictive group: 67%; liberal group: 78%); 23% of participants in the restrictive group and 9% in the liberal group correctly stated their treatment group. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Researchers concealed from group allocation collected questionnaire‐based measures at 60 and 180 days postrandomisation. Assessment of clinical outcomes was not documented to have been done blindly. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
There was good follow up. |
| Selective reporting (reporting bias) |
Low risk |
No reporting bias was apparent. |
| Other bias |
Low risk |
No other biases were apparent. |
