Impact of blood component transfusions, tranexamic acid and fluids on subarachnoid hemorrhage outcomes

For years, there have been many discussions about the optimal/beneficial threshold for transfusion of blood products in subarachnoid hemorrhage (SAH), and it remains to be established. Over the period spent by patients who are recuperating from such acute intracranial bleeding, they often become anemic. This is a rationale why these patients are considered candidates for transfusion to restore normal hemoglobin levels and optimal arterial oxygen content. After a comprehensive review of multidisciplinary studies, it becomes evident that the benefits of blood transfusion may vary greatly depending on the situation. The objective here is to summarize the reported outcomes following administration of blood products, i.e., platelets, tranexamic acid, prothrombin complex concentrate, red blood cells, and colloids/crystalloids for optimal oxygenation and to minimize rebleeding. These treatments are reviewed in the context of how they interact with the brain during the early brain injury, the vasospasm, microthrombus formation, inflammation, brain edema, and the delayed cerebral ischemic phases. In severe SAH, cardiac dysfunction and hyponatremia are not uncommon, and the transfusion-associated circulatory overload should be monitored. Thus, continuous hemodynamic monitoring is necessary to prevent pulmonary edema, along with the maintenance of euvolemia. The paper also highlights conditions when transfusion is contraindicated. Patient blood management programs should be promoted to develop clearer hospital transfusion guidelines to strive for optimization of patient hemoglobin and iron stores, and to train for more restrictive RBC policy. The results reported thus far need to be critically reviewed by a panel of experts, along with the need to design novel rigorous prospective parallel-group studies to establish SAH-specific guidelines.