Transfusion-related acute lung injury (TRALI): a serious adverse event of blood transfusion.

BACKGROUND AND OBJECTIVES: Analyses of fatal transfusion reactions in the UK and USA have shown that transfusion-related acute lung injury (TRALI) is among the most common causes of fatal transfusion reactions.

MATERIAL AND METHODS: Review of the literature was used to analyse TRALI.

RESULTS: TRALI is characterized by acute respiratory distress and non-cardiogenic lung oedema developing during, or within 6 h of, transfusion. In atypical cases, TRALI can become symptomatic much later. TRALI must be carefully differentiated from transfusion-associated circulatory overload. In its fulminant presentation, TRALI can be clinically indistinguishable from acute respiratory distress syndrome occurring as a result of other causes. The severity of TRALI depends upon the susceptibility of the patient to develop a more clinically significant reaction as a result of an underlying disease process, and upon the nature of triggers in the transfused blood components, including granulocyte-binding alloantibodies (immune TRALI) or neutrophil-priming substances such as biologically active lipids (non-immune TRALI). Immune TRALI, which occurs mainly after the transfusion of fresh-frozen plasma and platelet concentrates, is a rare event (about one incidence per 5000 transfusions) but frequently ( approximately 70%) requires mechanical ventilation (severe TRALI) and is not uncommonly fatal (6-9% of cases). Non-immune TRALI, which occurs mainly after the transfusion of stored platelet and erythrocyte concentrates, seems to be characterized by a more benign clinical course, with oxygen support sufficient as a form of therapy in most cases, and a lower mortality than immune TRALI.

CONCLUSIONS: By virtue of its morbidity and mortality, TRALI has become one of the most serious current complications of transfusion. To prevent further antibody-mediated cases, the evaluation of TRALI should include leucocyte antibody testing of implicated donors. However, further studies are necessary for the prevention of this serious transfusion complication.