Case History

A 40-year man was brought to the ER with multiple injuries due to MVA. On arrival BP 60/35 mm Hg, HR 125 bpm. He transfused with 5 units of type O, Rh + whole blood over 25 minutes which improved BP to 90/50 mm Hg. After transfusing 5 more units BP dropped to 50/30 mm Hg, and the HR rises to 130 bpm. The electrocardiogram shows a QT interval of 470 msec. Central venous pressure increases from 10 to 22 cmH2O.

What is the most likely cause of the patient's current condition?

A. Citrate toxicity
B. Hemolytic transfusion reaction
C. Transfusion-related acute lung injury
D. Hyperkalemia

Correct Answer: A.Citrate toxicity

Discussion:

Stored blood contains citrate, an anticoagulant that binds ionized calcium.

When stored whole blood is rapidly transfused ,the citrate binds with calcium, producing transient decreases in ionized calcium. The abrupt decrease in ionized calcium can lead to prolonged QT intervals, an increase in left ventricular end-diastolic pressure, and arterial hypotension.

Case contributed by: Katayoun Fomani, M.D., Associate Professor, Laboratory Medicine, Program Director, Transfusion Medicine Fellowship, UAB Pathology