From the Guidelines
Transfusion-associated lung injury (TRALI) should be managed with immediate cessation of transfusion and supportive care, including oxygen supplementation and ventilatory support, as it is a serious complication of blood transfusion with a mortality rate of 5-10%. The incidence of TRALI has been significantly reduced with the implementation of male-only plasma donors, as seen in the UK since 2003 1. According to the 2016 AAGBI guidelines, the use of male-only plasma in component therapy has decreased the incidence of TRALI 1.
Prevention and Treatment
Prevention is crucial and includes:
- Using male-only plasma donors
- Screening female donors for HLA antibodies
- Implementing leukoreduction of blood products When TRALI is suspected, the transfusion should be immediately stopped, and the blood bank notified to quarantine related products. Treatment is primarily supportive care, focusing on oxygen supplementation and ventilatory support as needed. Patients should be monitored in an intensive care setting with continuous pulse oximetry and may require mechanical ventilation in severe cases.
Pathophysiology
TRALI occurs due to neutrophil activation in the lungs triggered by either donor antibodies against recipient leukocytes or by bioactive substances in stored blood products that prime neutrophils, leading to pulmonary capillary damage, increased permeability, and non-cardiogenic pulmonary edema. The risk of TRALI has been estimated to be around 8.1 per 100,000 transfused blood components 1.
Outcome
Most patients recover within 48-96 hours with appropriate supportive care, though mortality rates of 5-10% have been reported. The risk of TRALI should be weighed against the benefits of blood transfusion, and efforts should be made to minimize this risk through careful donor screening and component selection.
From the Research
Definition and Diagnosis of Transfusion Associated Lung Injury
- Transfusion-related acute lung injury (TRALI) is defined as the onset of acute hypoxia within 6 hours of a blood transfusion in the absence of hydrostatic pulmonary oedema 2.
- Diagnostic criteria for TRALI include hypoxia and bilateral pulmonary edema occurring during or within 6 h of a transfusion in the absence of cardiac failure or intravascular volume overload 3.
- TRALI must be carefully differentiated from transfusion-associated circulatory overload, and in its fulminant presentation, can be clinically indistinguishable from acute respiratory distress syndrome occurring as a result of other causes 4.
Pathogenesis of Transfusion Associated Lung Injury
- The pathogenesis of TRALI is related to the infusion of donor antibodies that recognize leucocyte antigens in the transfused host or the infusion of lipids and other biological response modifiers that accumulate during the storage or processing of blood components 5.
- Leukocyte antibodies in donor plasma have been implicated in most cases, with antibodies directed at human leukocyte antigen (HLA) class I, HLA class II or neutrophil-specific antigens, particularly HNA-3a 3.
- Activation of pulmonary endothelium is important in the development of TRALI and may account for most cases being observed in surgical or intensive care unit patients 3.
Treatment and Management of Transfusion Associated Lung Injury
- Treatment is supportive with oxygen and mechanical ventilation, and diuresis is not indicated 3.
- The cornerstone of TRALI management is supportive care with oxygen supplementation and ventilatory assistance when needed, and conservative fluid practices are desirable, provided care is taken to avoid hypotension 6.
- The literature is not currently sufficient to support either corticosteroids or statins as effective therapies in TRALI 6.
Prevention of Transfusion Associated Lung Injury
- Preventative strategies have shown the most promise in mitigating this transfusion-related pulmonary complication, including conservative transfusion practices and deferral of high-plasma component donors who have, or are at high risk of having, anti-human leukocyte antigen and/or anti-human neutrophil antigen antibodies 6.
- Exclusion of "at risk" donors and pooling of high plasma volume products have shown to reduce the TRALI incidence effectively 2.
- The use of leucoreduced components, fresher blood/blood components, and solvent detergent plasma are also discussed as potential preventive strategies 5.