What is the treatment and etiology of Transfusion-Related Acute Lung Injury (TRALI)?

From the Guidelines

Transfusion-Related Acute Lung Injury (TRALI) is a clinical syndrome that presents as acute hypoxemia and non-cardiogenic pulmonary edema during or after blood transfusion, and its treatment involves supportive care and avoidance of further transfusions.

Etiology

• TRALI is often associated with the transfusion of blood components, particularly plasma-containing products 1
• The exact mechanism of TRALI is not fully understood, but it is thought to involve the transfusion of antibodies against human leukocyte antigens (HLA) or human neutrophil antigens (HNA) 1

Treatment

• Supportive care: The mainstay of treatment for TRALI is supportive care, including oxygen therapy, mechanical ventilation, and fluid management 1
• Avoidance of further transfusions: All efforts should be made to avoid further transfusions in patients who have developed TRALI, as this can exacerbate the condition 1
• Diagnosis and reporting: It is essential to diagnose and report TRALI to the local blood bank, as this can help identify high-risk donors and prevent future cases 1

Prevention

• Screening of blood donors: Screening of blood donors for HLA and HNA antibodies can help reduce the risk of TRALI 1
• Use of plasma-reduced blood components: The use of plasma-reduced blood components, such as washed red blood cells, can also reduce the risk of TRALI 1
• Transfusion protocols: Implementing strict transfusion protocols, including the use of transfusion triggers and careful monitoring of patients, can help minimize the risk of TRALI 1

From the Research

Etiology of Transfusion-Related Acute Lung Injury (TRALI)

• TRALI is caused by the transfusion of either anti-leukocyte antibodies or biological response modifiers (BRMs) 2, 3, 4, 5, 6
• The pathogenesis of TRALI may be explained by a "two-hit" hypothesis, with the first "hit" being a predisposing inflammatory condition and the second hit involving the passive transfer of neutrophil or HLA antibodies from the donor or the transfusion of biologically active lipids from older, cellular blood products 3, 4, 6
• Experimental evidence suggests at least six different pathways that antibody-mediated TRALI might follow, including two hit neutrophil activation, monocyte and neutrophil dependent, and endothelial cell activation 2

Treatment of Transfusion-Related Acute Lung Injury (TRALI)

• Treatment is supportive, with a prognosis substantially better than most causes of clinical acute lung injury 3, 5
• The main strategy in combating TRALI is prevention, both through manipulation of the donor pool and through clinical strategies directed at reducing transfusion of blood products, including evidence-based lower transfusion thresholds 5
• Avoidance strategies, such as male-only transfusion practices, the use of leucoreduced components, fresher blood/blood components, and solvent detergent plasma, are also discussed 4

Key Factors in TRALI

• Critically ill patients are more susceptible to TRALI and require special attention by critical care specialists, haematologists, and transfusion medicine experts 4
• TRALI can occur with any type of blood product and can occur with as little as one unit 5
• The presentation of TRALI is similar to other forms of acute lung injury, and management is predominantly supportive 5