Blood product transfusions are frequently performed during critical illnesses. Primarily; erythrocyte suspension, platelet suspension and fresh frozen plasma transfusions are performed. It should not be forgotten that these procedures, which have positive effects on the survival and healing process of patients, may also cause side effects and increase morbidity and mortality. Therefore, it is necessary to determine the indications of transfusions correctly and determine the goals according to the patient characteristics. There are many studies done in this regard. In light of these studies, several guidelines have been prepared. Through these studies and these guidelines, avoidance of unnecessary transfusions and optimum benefit in transfusions are aimed. Regarding transfusion of erythrocyte suspensions in the general population, higher target hemoglobin levels have not been shown to be superior to lower target levels. In addition, target hemoglobin levels should be individualized in septic patients and the patients with cardiovascular comorbidities. While giving platelet transfusion, the transfusion decision should be made considering the risk of spontaneous bleeding and the risk of bleeding during possible interventions. The transfusion should be avoided in cases of low bleeding risks or non-risk events. Fresh frozen plasma transfusions should be performed with correct indications and the bleeding risk should be taken into account. During and after transfusion of all blood products transfusion reactions may develop; appropriate precautions should be taken and prompt treatment should be given as needed.

Keywords: Blood Transfusion, Transfusion Reaction, Critical Illness, Erythrocyte Transfusion, Platelet Transfusion, Blood Omponent Transfusion