TRAIN

Background

Although blood transfusions can be lifesaving in severe hemorrhage, they could also result in several potential complications. As anemia has also been associated with poor outcome in critically ill patienst, optimal transfusion trigger is a real challenge for clinicians. This is even more important in patients with acute brain injury who were not specifically evaluated in previous large randomized clinical trial dealing with the optimal transfusion threshold. Neurological patients may be particularly sensistive to anemic brain hypoxia because of the exhausted cerebrovascular reserve, which adjust cerebral blood flow to tissue oxygen demand.