Red Blood Cell Unit Utilization in the ICU: Evidence and Confidence

Anemia is an almost universal phenomenon (ninety five percent) among critically ill patients, especially if they stay in the ICU more than 3 days. Forty to fifty percent of such patients receive red blood cell transfusions. Blood loss (due to blood sampling), iron reduced availability and utilization and cytokine mediated bone marrow suppression account for this loss of red blood cell mass. Anemia is itself associated with worse outcomes, independently of the nature of underlying disease. Transfusion therapy nevertheless, probably is not the ideal solution as it is related to increased mortality and hospital infections. Both the degree of anemia and transfusion intensity could represent either causative influences or merely surrogate markers of severe illness, posing significant difficulties on the interpretation of investigational results. Currently, restriction of red blood cell transfusion threshold to 7g/l has become the standard practice. Following the famous TRICC trial which introduced the low threshold concept, the few predicted exceptions regarding sepsis, hemorrhage or cardiac disease were addressed with new studies. The results of these studies force towards the implementation of the restrictive strategy throughout the whole transfusion indications spectrum in the ICU, with the exception of the symptomatic coronary patients. In order to minimize transfusion intensity however, acute context care must be optimum, multidisciplinary treatment approaches and support being timely provided.