Age of Blood in Brain Injury

Donated red blood cells vary in how old they are, that is, how long they have been stored since being collected from donors. Blood that has been donated is stored for a maximum of 42 days, after this time it is expired. That means that red blood cells that are given to patients as a blood transfusion can be anywhere from a few days old to 42 days old. The average age of blood that is given as a blood transfusion in this hospital is 21 days old. As stored blood gets older its ability to carry oxygen may be reduced. Whether or not this is important in patients with a brain injury is not currently known. The purpose of this study is to try and determine if fresh blood (less than 5 days old) is better than old blood (greater than 20 days old) in improving the supply of oxygen in patients who have suffered an injury to their brain.