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Restrictive Versus Liberal Transfusion Strategies for Older Mechanically Ventilated Critically Ill Patients: a Randomized Pilot Trial
Study Question: What is the impact of liberal versus restrictive transfusion strategies in patients mechanically ventilated and ≥ 55 years old?
Study Description: This was a multicenter randomized pilot trial in six United Kingdom ICUs conducted from August 2009 to December 2010. Patients were included if they: were ≥ 55 years old; had a hemoglobin level (Hgb) ≤ 9.0; and were to require at least 4 days of mechanical ventilation. Patients were randomized to liberal transfusion strategy (Hgb trigger ≤ 9 g/dL, target 9.1 – 11 g/dL) or restrictive (Hgb trigger ≤ 7 g/dL, target 7.1 – 9 g/dL) for 14 days or until ICU discharge. Patients were given 1 unit of red blood cells (RBC) at a time. Exclusion criteria included: active bleeding, traumatic brain injury, intracranial hemorrhage, or active receipt erythropoietic stimulating agents. The primary outcome was the difference in mean Hgb among groups. Secondary outcomes included RBC use, mortality, quality of life, and antibiotic- and ventilator-free days.
Results: A total of 100 patients were included, with 69% of patients receiving RBC prior to randomization. Baseline characteristics were similar between groups. Mean Hgb was 8.19 g/dL (SD 5.1) in the restrictive group and 9.57 g/dL (SD 6.3) in the liberal group (p < 0.0001). RBC use was a median of 2 units (IQR 0 – 4) in the restrictive group and 3 units (IQR 2 – 5) in the liberal group (p = 0.002). There was no significant difference in mortality or antibiotic- or ventilator-free days. The mental component score of the quality of life survey was significantly improved in the restrictive group by 12.1 points (95% CI, 0.2 – 24.1). The adverse events were similar between groups, but there were numerically more thrombotic events in the restrictive group (11.8% vs. 6.1%).
Conclusion(s): A large trial of transfusion strategies in older mechanically ventilated patients is feasible.
Perspective: The results of this trial corroborate some of the findings from the landmark Transfusion Requirements in Critical Care (TRICC) trial.