Transfusion-Related Acute Lung Injury (TRALI)

By Tanya Petraszko, MD FRCPC and Heather Hume, MD FRCPC

Description and Incidence

Transfusion-Related Acute Lung Injury (TRALI) is a syndrome characterized by acute respiratory distress following transfusion. All plasma-containing blood products have been implicated including rare reports of IVIG and cryoprecipitate. It is a rare complication of allogeneic blood transfusion but the incidence has not been well established due to difficulty in defining the syndrome and to variable reporting mechanisms worldwide. Various studies have estimated the overall frequency of TRALI to be between 1/1,120 and 1/57,810 units transfused. However, there is wide discrepancy in the literature with the reported frequency is as low as 1/557,000 RBC units and as high as 1/432 platelet units.

TRALI is associated with a high morbidity with the majority of patients requiring ventilatory support. However, the lung injury is generally transient with PO2 levels returning to pretransfusion levels within 48 -96 hours and CXR returning to normal within 96 hours. TRALI is associated with a significant mortality rate, often approximated at 5 to 10%. Given the gains in safety made within the blood component production industry, particularly with respect to transmission of infectious diseases, TRALI is now among the three leading causes of transfusion related fatalities along with ABO incompatibility and bacterial contamination.