To investigate the long-term influence of erythrocyte transfusion on cerebral oxygenation in patients with severe traumatic brain injury.

Prospective and observational study.

Neurotrauma intensive care unit of trauma center level I.

Sixty consecutive, hemodynamically stable patients with severe traumatic brain injury, pretransfusion hemoglobin < 100 g/l, non-bleeding and monitored through intracranial pressure and brain tissue partial pressure of oxygen (PtiO₂) catheters were included.

Transfusion of 1–2 units of red blood cells.

Ten sets of variables (pretransfusion, end of transfusion, and 1, 2, 3, 4, 5, 6, 12 and 24 h after transfusion) were recorded, including: PtiO₂, cerebral perfusion pressure (CPP), end-tidal CO₂, peripheral saturation of oxygen, temperature, hemoglobin, lactate and PaO₂/FiO₂ ratio. Transfusion was associated with an increase in PtiO₂ during a 6-h period, with a peak at 3 h (26.2%; p = 0.0001) in 78.3% of the patients. No relationship was observed between PtiO₂, CPP and hemoglobin increments. The relative increment in PtiO₂ at hour 3 was only correlated with baseline PtiO₂ (r² 0.166; p = 0.001). All of the patients with basal PtiO₂ < 15 mmHg showed an increment in PtiO₂ versus 74.5% of patients with basal PtiO₂ ≥ 15 mmHg (p < 0.01, hour 3).

Erythrocyte transfusion is associated with a variable and prolonged increment of cerebral tissue oxygenation in anemic patients with severe traumatic brain injury. Low baseline PtiO₂ levels (< 15 mmHg) could define those patients who benefit the most from erythrocyte transfusion.