While âBRBâ is most widely used in the context of real-time chat, the term has been also discussed on Usenet, including a post on the alt.usage.english newsgroup on January 13th, 1994.
Blood transfusions are done to replace blood lost during surgery or due to a serious injury. A transfusion also may be done if your body can't make blood properly because of an illness. During a blood transfusion, a small needle is used to insert an IV line into one of your blood vessels. Through this line, you receive healthy blood. The procedure usually takes 1 to 4 hours, depending on how much blood you need. Blood transfusions are very common. Each year, almost 5 million Americans need a blood transfusion.
I don't know what blood bank does to preserve blood for transfusion but if donated human blood is shipped out for research lab, the label says it will expire in 25 days. However, after keeping it in the fridge (2-8 oC) by the 7th day, blood is not good anymore, with aggregation, hemolysis, etc.