Transfusion-Related Acute Lung Injury

Transfusion reactions are adverse events that occur after transfusing blood products such as whole blood, fresh frozen plasma (FFP), platelets, cryoprecipitate, granulocytes, intravenous immune globulin, allogenic and autologous stem cells, and packed red blood cells. Transfusion-related acute lung injury (TRALI), is a clinical syndrome in which there is acute, noncardiogenic pulmonary edema associated with hypoxia that occurs during or after a transfusion. It is the leading cause of death from transfusion documented by the U.S. Food and Drug Administration (FDA). Specifically, an incident of TRALI includes 1 in 5000 units of packed red blood cells, 1 in 2000 plasma-containing components, and 1 in 400 units of whole-blood-derived platelet concentrates. TRALI was first reported in the 1950s but recognized as a distinctive clinical syndrome in 1983. The disorder is not only diagnosed clinically but is usually confirmed by radiographic findings. Diagnostic criteria for TRALI is if the symptoms develop during or within 6 hours of transfusion without any risk factors for developing acute lung injuries such as sepsis from pneumonia, aspiration, and shock. Physical symptoms include fever, hypotension, and tachycardia. Clinical findings include exudative bilateral infiltrates on chest radiograph, no evidence of pulmonary vascular overload, and hypoxemia of SpO2 less than 90% on room air with a ratio of the partial pressure of oxygen to a fractional inspired oxygen concentration of less than 300 mmHg. Possible TRALI is when there are other risk factors for acute lung injury. Delayed TRALI is when transfusion is completed after 6 to 72 hours, and it is associated with higher mortality. Transfusion-related circulatory overload (TACO) needs to be ruled out as it can be on differential diagnosis due to the similarity of pulmonary edema picture, but due to actual volume overload. In the US, TRALI has to be reported to the Blood Banking services.