Although liberal blood transfusion has become a standard means of treating anemia in brain-injured intensive care patients, recent data has shown that transfusion could be associated with increased mortality and composite complications including multi-organ failure. The findings in this article are of particular interest in the management of traumatic brain injury (TBI), since they focus on anemia and transfusions. A previously published study showed that transfusion was associated with increased brain oxygenation, while other studies demonstrated the opposite effect of transfusion, i.e. reduced oxygenation. As for anemia, some studies showed that a lower Hb level was associated with improved outcomes and other studies showed negative effects of anemia on TBI patients. In view of these mixed results, a recent retrospective study examined the effect of anemia in TBI patients, hypothesizing that blood transfusion would lead to favorable outcomes.

Over the 7-year study period, Hb levels and transfusions were recorded for 1,150 patients with TBI. Of these patients, 46% were anemic (defined as Hb level <9 g/dL) at some point during their first week of admission. This group experienced significantly more complications than that of nonanemic patients. Of the anemic group, 76% received blood transfusions during their first week. Transfusion in this group was associated with more complications and a higher mortality rate than patients who were not transfused. The impact of anemia in the transfused patients was silent but when the transfusion factor was excluded in a logistic regression models, anemia emerged as a significant risk factor for both mortality and complications. In addition, higher risks for mortality and complications were observed with increasing amounts of blood transfused.

Both anemia and transfusion were shown to be independent risk factors for adverse events and mortality. The authors recommend that both anemia and transfusion should be assessed together in TBI patients since in some subgroup the risk of anemia may overshadow that of transfusion. In terms of administration, transfusion may best be reserved for TBI patients on an individualized basis, in which the choice to use transfusions is based on physiologic indications, rather than a achieving a specific Hb threshold. Based on their findings the authors recommended that liberal transfusion policies in TBI patients be abandoned and more studies should be performed to address outcomes in this population.

Salim A, Hadjizacharia P, DuBose J, Brown C, Inaba K, Chan L, Margulies DR. Role of anemia in traumatic brain injury. J Am Coll Surg. 2008 Sep;207(3):398-406.

NAAC Expert Commentary:
Trauma patients represent a complex array of physiologic derangements and multiple confounders making them a difficult population to study. High prevalence of early mortality in the severely injured represent the select population that may benefit from specific interventions. Despite this, those who survive may still have severe injuries and continue to bleed, resulting in significant anemia. TBI patients represent more of a challenge since for any trauma patient, brain injury places them at a high risk, if not the highest. In an attempt to achieve the best possible outcomes, high Hb levels were (and still are) targeted as treatment with little or conflicting evidence.

This well conducted retrospective study (although suffering form no control group), analyzed the TBI patients by grouping them into anemic versus nonanemic, transfused and nontransfused cohorts. Although there were many confounders, transfusion for the anemic and nonanemic remained an independent factor associated with negative outcomes, including renal failure and mortality. The most common reason for transfusion in this study was hemorrhage and anemia. Management of hemorrhage is still dominated with transfusion support but options for treatment of anemia other than transfusion are available. This study demonstrates that anemia is detrimental (independent risk factor for negative outcome) and that transfusion therapy for anemia compounds the problem. Therefore, reassessment of any transfusion decision is sorely needed and slowly gaining acceptance.

As the authors suggest, more studies are needed to determine if a TBI subpopulation exists, which might still benefit from transfusion, and determine if transfusion would attenuate the negative outcomes associated with anemia. Moreover, other treatment modalities for anemia need to be studied to determine whether negative effects of anemia can be reversed, leading to improvement in morbidity and mortality rates.

Last Updated: January 7, 2009