Factors Associated With Brain Tissue Oxygenation Changes After RBC Transfusion in Acute Brain Injury Patients.

Objectives: Anemia is common after acute brain injury and can be associated with brain tissue hypoxia. RBC transfusion (RBCT) can improve brain oxygenation; however, predictors of such improvement remain unknown. We aimed to identify the factors associated with PbtO2 increase (greater than 20% from baseline value) after RBCT, using a generalized mixed model.
Design: This is a multicentric retrospective cohort study (2012-2020).
Setting: This study was conducted in three European ICUs of University Hospitals located in Belgium, Switzerland, and Austria.
Patients: All patients with acute brain injury who were monitored with brain tissue oxygenation (PbtO2) catheters and received at least one RBCT.
Intervention: Patients received at least one RBCT. PbtO2 was recorded before, 1 hour, and 2 hours after RBCT.
Measurements and Main Results: We included 69 patients receiving a total of 109 RBCTs after a median of 9 days (5-13 d) after injury. Baseline hemoglobin (Hb) and PbtO2 were 7.9 g/dL [7.3-8.7 g/dL] and 21 mm Hg (16-26 mm Hg), respectively; 2 hours after RBCT, the median absolute Hb and PbtO2 increases from baseline were 1.2 g/dL [0.8-1.8 g/dL] (p = 0.001) and 3 mm Hg (0-6 mm Hg) (p = 0.001). A 20% increase in PbtO2 after RBCT was observed in 45 transfusions (41%). High heart rate (HR) and low PbtO2 at baseline were independently associated with a 20% increase in PbtO2 after RBCT. Baseline PbtO2 had an area under receiver operator characteristic of 0.73 (95% CI, 0.64-0.83) to predict PbtO2 increase; a PbtO2 of 20 mm Hg had a sensitivity of 58% and a specificity of 73% to predict PbtO2 increase after RBCT.
Conclusions: Lower PbtO2 values and high HR at baseline could predict a significant increase in brain oxygenation after RBCT.
Competing Interests: The authors have disclosed that they do not have any potential conflicts of interest.
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