Anemia and Transfusion in Critical Care: Physiology and Management.

OBJECTIVE: The objective of this report is to review the physiology and management of anemia in critical care. Selected publications on physiology and transfusion related to anemia and critical care, including the modern randomized trials of conservative versus liberal transfusion policy, were used. Anemia is compensated and tolerated in most critically ill patients as long as oxygen delivery is at least twice oxygen consumption. There are risks to blood transfusion which can be minimized by blood banking practice. The availability of cultured red cells may allow correction of anemia without significant risk. The benefit of transfusion in anemia must be weighted against the risk in any specific patient. CONCLUSION AND RECOMMENDATION: In a criticially ill patient, anemia should be managed to avoid oxygen supply dependency (oxygen delivery less than twice comsumption) and to maintain moderate oxygen delivery reserve (DO2/VO2 > 3).