Definition Massive Blood Loss
n Commonly defined as replacement of patient’s
total blood volume or transfusion of >10 units
of blood within 24 hours
n eg   in a 70kg adult - translates to an estimated
replacement of 4-5L of blood lost, or the transfusion of 16-
20 units of packed RBC
n 2nd definition: replacement of 50% of
circulating blood volume in <3hrs or bleeding
>150ml/min
n (Normal blood volume approximately 7% of
ideal body weight in adults)
n 70 ml X Kg