A 26-year-old man is resuscitated with packed red blood cells following a motor vehicle collision complicated by a fractured pelvis and resultant hemorrhage. A few hours later the patient becomes hypotensive with a normal central venous pressure (CVP), oliguric, and febrile. Upon examination, the patient is noted to have profuse oozing of blood from his intravenous (IV) sites. Which of the following is the most likely diagnosis?

Transfusion reactions can be categorized into hemolytic versus allergic nonhemolytic reactions. Hemolytic transfusion reactions are caused by complementmediated destruction of transfused red blood cells by the recipient's preexisting antibodies. Severe hemolytic transfusion reactions usually involve the transfusion of ABO-incompatible blood, with fatalities occurring in 1 in 600,000 units. Peptides from the complement, released into the blood as the red blood cells are rapidly destroyed, cause hypotension, activate coagulation, and lead to disseminated intravascular coagulation (DIC). Symptoms of a hemolytic transfusion reaction include fever, chills, pain and redness along the infused vein, oozing from IV sites, respiratory distress, anxiety, hypotension, and oliguria. The patient would have a low CVP with hypovolemic shock. Acute adrenal insufficiency, gram-negative bacteremia, and ureteral obstruction would not cause oozing from the IV sites.