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.