Red blood cell transfusion in neurocritical patients: an updated systematic review and meta-analysis

Anemia is a prevalent complication in neurocritical patients and contributes to secondary brain damage by diminishing the oxygen supply to the brain. Although red blood cell transfusions may enhance cerebral oxygen delivery, whether this intervention improves patient outcomes remains unclear.

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE (PubMed) from inception to January 26, 2025. All randomized controlled trials (RCTs) assessing liberal versus restrictive RBC transfusion strategies in neurocritical patients were included in this analysis. The primary outcome was mortality at discharge.

A total of 5579 bibliographic citations were identified. After reviewing the title, abstract, and full text, 8 studies were deemed eligible for inclusion. The combined results showed no significant difference in mortality at discharge (20.5% for restrictive strategy vs. 20.8% for liberal strategy, RR: 0.98, 95% CI: 0.76 to 1.26, I² = 21%). There was no significant difference between the restrictive and liberal transfusion groups in terms of ICU mortality (RR: 1.36, 95% CI: 0.52 to 3.52), six-month mortality (RR: 1.05, 95% CI: 0.90 to 1.22) or long-term mortality (RR: 1.04, 95% CI: 0.91 to 1.18). However, the combined results showed that the incidence of unfavorable Glasgow Outcome Scale (GOS) outcomes at 6 months (RR: 1.12, 95% CI: 1.05 to 1.20) and long-term unfavorable outcomes (RR: 1.12, 95% CI: 1.05 to 1.19) was significantly lower in the liberal transfusion group compared to the restrictive transfusion group. The long-term unfavorable outcomes were significantly lower in the liberal transfusion group compared to the restrictive group in traumatic brain injury subgroup (RR: 1.10, 95% CI: 1.02 to 1.19). Additionally, the incidence of sepsis or septic shock was lower in the liberal transfusion group than in the restrictive transfusion group (RR: 1.37, 95% CI: 1.05 to 1.80).

Combining our findings, this systemic review suggests that while both transfusion strategies had similar impacts on mortality outcomes, the liberal strategy may offer a better prognosis in terms of long-term recovery and a reduced risk of sepsis.