MASSIVE BLOOD TRANSFUSION defined as 1) adults a) replacement of >1 blood volume in 24 hours ,or b) >50% of blood volume in 4 hours (adult blood volume is approximately 70 mL/kg). 2) children, • transfusion of >40 mL/kg (blood volume in children over 1 month old is approximately 80 mL/kg). Initially TRANSIENT HYPERGLYCEMIA due to glucose in preservatives; this leads to insulin release and may cause HYPOGLYCEMIA Overall most commonly--- HYPOGLYCEMIA > HYPERGLYCEMIA. Most Common cause of death after massive blood transfusion is--- DIC (massive RBC transfusion without concomitant repletion of clotting factors may lead to a dilutional coagulopathy.) 2)TRALI (Transfusion-Related Acute Lung Injury) is the most common cause of major morbidity and death after transfusion. It presents as an acute respiratory distress syndrome (ARDS) either during or within 6 h of transfusion.Most commonly a/w FFP transfusion.