Les pratiques transfusionnelles en réanimation Transfusion practices in the intensive care unit

Blood transfusions are a common event in the ICU with about a third of all patients receiving a transfusion at some point during their ICU stay. The theoretical rationale behind blood transfusion is fairly clear-cut: by increasing the hemoglobin concentration, oxygen delivery to the tissues will be improved and organ function optimized. However, in reality the situation is more complex. While increasing red cell mass may indeed increase oxygen delivery, there may not be a corresponding increase in oxygen uptake and tissue oxygen availability. In fact, despite traditional transfusion triggers set in the region of a hemoglobin value of 10 g/dl or a hematocrit of 30%, there is evidence that the system can tolerate much lower levels of anemia with few or no adverse effects. Several studies have suggested an increase in mortality in transfused patients, however, while many patients may indeed tolerate a lower hemoglobin value than traditionally thought, anemia is not a benign feature and acutely anemic patients also have higher mortality rates. The ‘optimal’ hemoglobin is, thus, a balance between the benefits of maximum hemoglobin levels and the potential adverse effects of blood transfusion and high hematocrit. In this article we will discuss some of the epidemiological data surrounding this issue and how its implications for transfusion practice in the ICU. © 2003 Societe de reanimation de langue francaise. Publie par Elsevier SAS. Tous droits reserves.