Discussion
The present patient showed reduced blood oxygenation levels after platelet transfusion and foamy endotracheal secretions. Therefore, TRALI was strongly suspected during the surgery. TRALI is characterized by hypoxemia within 6 hours after blood transfusion and bilateral lung infiltrations on chest X-ray [5]. There are 2 types of TRALI (types I and II). The present case appeared to be TRALI type I based on his symptoms and clinical course [6]. Repeated suction of endotracheal serous discharge and the recruitment maneuver at FiO21.0 was performed during surgery to ensure oxygenation. The present case of TRALI had a good clinical course with systemic organ support by VV-ECMO in the ICU.
Two underlying mechanisms of TRALI are considered, immunological and non-immunological mechanisms [6]. As the immunological mechanism, donor or recipient-derived antibodies against human leukocyte antigens (HLAs) and human neutrophil antigens (HNAs) have antigen-antibody reactions and activate complement and white blood cells, which may increase pulmonary vascular permeability resulting in non-cardiogenic pulmonary edema [7]. As a non-immunological mechanism, pulmonary vascular endothelial cell injury is evoked by certain causes, and cytokines and active lipids within transfused blood may be associated with the development of non-cardiac edema [8]. However, the true pathogenesis has not yet been elucidated. In the present case, anti-HLA Class-II antibody within transfused donor serum may have reacted with recipient white blood cells, which triggered the onset of TRALI. The previous hematological malignancy and heart disease were thought to be recipient risks for TRALI, and platelet product transfusion and anti-HLA/HNA antibodies were donor risks for TRALI [5]. Though the present case showed TRALI, the possibility that the large volumes of transfusion and fluid therapy during the operation caused an excess volume load postoperatively could not be ruled out.
There are no established effective medications and/or specific treatments for TRALI, and only supportive and symptomatic therapies are currently given. Although there is a report that steroid was used for TRALI treatment [9], the effectiveness of steroid for TRALI has not yet been proven [10]. We are not aware of any previous reports that VV-ECMO was used for TRALI treatment. Lee et al. reported a case of hypoxemia and circulatory collapse after transfusions of red blood cells, platelets, and fresh-frozen plasma that was rescued by venoarterial-ECMO (VA-ECMO) support [11]. Nouraei et al. reported a 4-year-old case of TRALI caused by transfusion of fresh-frozen plasma during open-heart surgery with cardiopulmonary bypass that required postoperative VA-ECMO support for 15 hours [12]. Kuroda et al. reported a TRALI case after transfusion of packed red blood cells and fresh-frozen plasma at hepatectomy [13]. Their case received VV-ECMO due to a reduced P/F of 76 on the second ICU day. Blood oxygenation improved within a short time, and the patient was successfully weaned off VV-ECMO on the 4th ICU day and mechanical ventilation on the 8th ICU day. TRALI is a reversible disturbance in which many cases recover within 24 to 48 hours after onset. However, some cases deteriorate and require prolonged treatment [14]. In cases whose status deteriorates rapidly with life-threatening hypoxemia and poor respiratory status, VV-ECMO support appears to be effective. A case of TRALI that developed during surgery in which VV-ECMO was effective was described.
The present case of TRALI was triggered by intra-operative platelet transfusion and required VV-ECMO support. Further studies are necessary to elucidate the underlying mechanisms of TRALI, and technical progress in antibody detection methods is needed to prevent TRALI and develop new treatments. Results from large-scale clinical studies of the intraoperative management of TRALI are needed to improve the clinical outcome of this pathological condition.