age of red blood cells and transfusion

http://www.buzzle.com/articles/red-blood-cells.html

Anaemia is common in critically ill patients: up to 90 per cent of patients will be anaemic by day three of their intensive care unit stay.

Red blood cells transfusion rates in critically ill patients are reported between 20 per cent and 40 per cent in ICU, with a mean of 2 to 5 RBC units transfused per patient. Such anaemia of critical illness has been associated with a poor prognosis even in the absence of ischemic heart disease. This association supports the value of RBC transfusion in critically ill patients. Nonetheless, although potentially life-saving for individual patients, RBC transfusion also has been associated with an increased risk of morbidity and/or mortality in critically ill, surgical, and trauma populations.

In this setting, studies have increasingly focused on the possible deleterious role played by RBC storage duration (so-called age of red cells). In particular, they have raised concerns that prolonged RBC storage may lead to harm once such “older” red cells are transfused into ICU patients.

To avoid wasting RBC units and improve the provision of blood stock, standard practice worldwide consists of transfusing the oldest compatible and available RBC unit. In addition, RBC can be stored up to 42 days, maximising their availability and the likelihood that red cells older than two weeks will be transfused into critically ill patients.