In clinical practice, anemia is a clinical situation, which, according to present evidences, is met in 70% of hospitalized patients. The most efficient treatment for anemia is hemotransfusion and, the reason why we transfuse, is to preserve the tissue oxygenation the moment the compensatory mechanisms fail But although there are 200 years since the first hemotransfusions were carried out, despite of the technological advancements, field experts still have not found a strict international consensus about the creation of the transfusion protocols, which would be applicable in every clinical situation.The goal of our study is the avoidance of unnecessary transfusions, which expose the patient to many risks, but still strictly monitoring the tissue. Lactates are a systemic indicator of the tissue oxygenation and during our study, we have assessed the level of lactates in different values of hemoglobin in different clinical situations and pathologies to monitor the tissue oxygenation before and after transfusions.This study, which is the first of its kind, joins the trend of many international contemporary works in this field, which aim at increasing the efficiency of hemotransfusion.