Transfusion-related acute lung injury

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Transfusion-related acute lung injury
Other names	TRALI
Micrograph of diffuse alveolar damage, the histologic correlate of TRALI; H&E stain
Specialty	Pulmonology

Transfusion-related acute lung injury (TRALI) is the serious

It is often impossible to distinguish TRALI from acute respiratory distress syndrome (ARDS). The typical presentation of TRALI is the sudden development of shortness of breath, severe hypoxemia (O₂ saturation <90% in room air), low blood pressure, and fever that develop within 6 hours after transfusion and usually resolve with supportive care within 48 to 96 hours. Although low blood pressure is considered one of the important signs for diagnosing TRALI, in some cases high blood pressure can occur.^[3]

Delayed TRALI occurs 6 to 72 hours after transfusion completion. It is associated with a higher rate of mortality.^[4]

Cause

The cause of TRALI is currently not fully understood. 80–85% of cases are thought to be

TRALI is typically associated with plasma products such as fresh frozen plasma. TRALI can also occur in recipients of packed red blood cells, whether adult or pediatric patients.^[11] Due to the higher risk of TRALI resulting from donations by females, the AABB (formerly the American Association of Blood Banks) has recommended that those blood components with a high volume of plasma not be used for transfusion, but for further processing into other therapeutic products.^[12]

Pathophysiology

In TRALI, first-hit risk factors include long-term excessive alcohol use, shock, liver surgery, current smoking, higher peak airway pressure while undergoing mechanical ventilation, positive intravascular fluid balance, low levels of

It is a diagnosis upon examination of clinical manifestations that appear within 6 hours of transfusion, such as acute respiratory distress, tachypnea, hypotension, cyanosis, and dyspnea. TRALI is an uncommon syndrome, that is due to the presence of leukocyte antibodies in transfused plasma. It is believed to occur in approximately one in every 5000 transfusions.[3] Leukoagglutination and pooling of granulocytes in the recipient's lungs may occur, with release of the contents of leukocyte granules, and resulting injury to cellular membranes, endothelial surfaces, and potentially to lung parenchyma. In most cases leukoagglutination results in mild dyspnea and pulmonary infiltrates within about 6 hours of transfusion, and spontaneously resolves.^{[citation needed]}

Occasionally more severe lung injury occurs as a result of this phenomenon and acute respiratory distress syndrome (ARDS) results. Leukocyte filters may prevent TRALI for those patients whose lung injury is due to leukoagglutination of the donor white blood cells, but because most TRALI is due to donor antibodies to leukocytes, filters are not helpful in TRALI prevention. Transfused plasma (from any component source) may also contain antibodies that cross-react with platelets in the recipient, producing usually mild forms of posttransfusion purpura or platelet aggregation after transfusion.^{[citation needed]}

Another nonspecific form of immunologic transfusion complication is mild to moderate immunosuppression consequent to transfusion. This effect of transfusion is not completely understood, but appears to be more common with cellular transfusion and may result in both desirable and undesirable effects. Mild immunosuppression may benefit organ transplant recipients and patients with autoimmune diseases; however, neonates and other already immunosuppressed hosts may be more vulnerable to infection, and cancer patients may possibly have worse outcomes postoperatively.^{[citation needed]}

Treatment

The mainstay of therapy in TRALI is

The true incidence of TRALI is unknown because of the difficulty in making the diagnosis and because of underreporting. It is estimated to occur in 1:1300 to 1:5000 transfusions of plasma-containing products. TRALI is the leading reported cause of death related to transfusion in the United States; more than 20 cases were reported per year from 2003 to 2005.^[citation needed] The immune mediated form of TRALI occurs approximately once every 5000 transfusions and has a mortality of 6–9%.^[17]

See also

• Flash pulmonary edema

References