Red blood cells either useful or dangerous

Major differences in transfusion consumption exist between hospitals and between transfusion prescribers that remain difficult to explain by differences in case mix or context. Too often the transfusion of red cells is considered an innocent act while the human body possesses potent mechanisms to cope with even severe anaemia under stable conditions without important or active haemorrhage. Risks of viral transmission and transfusion errors are well known but rare. But there exist risks that are less obvious that seem to result in an excess of morbidity and mortality as compared to patients that are not transfused. The evidence from a multitude of observational studies and a few randomized controlled trials is getting overwhelming. These studies allow to conclude that transfusion of red cells is rarely necessary above 10 gr/dl. In between these Values it may be prudent to transfuse earlier in function of perceived risk for renal or cardiac damage in particular in patients with moderate, severe or unstable coronary insufficiency. (C) 2009 Elsevier Masson SAS. All rights reserved.