TRALI most common cause of transfusion related mortality (Miller, 7th ed).
Acute hemolytic reaction
Definition: When antibodies to a particular blood antigen already exist. Can be delayed if there is an amnestic response to a transfused RBC antigen to which the recipient is already sensitized.
Causes: Usually the result of ABO incompatibility and technical errors made during the collection of blood.
Risks: The risk of acute hemolytic transfusion reaction due to incompatible blood is 1:4 per 1 million units transfused and has a high fatality rate.
Most of the transfused cells are destroyed which can activate the coagulation system with DIC and release of anaphylotoxins and other vasoactive amines. Patients might present with back pain, pain at site of transfusion, headache, change in vital signs, pulmonary edema, bleeding, new/worsening renal failure.