Acute lung injury complicating blood transfusion in post-partum hemorrhage: incidence and risk factors

BACKGROUND: We retrospectively investigated the incidence and risk factors for transfusion-related acute lung injury (TRALI) among patients transfused for post-partum hemorrhage (PPH). METHODS: We identified a series of 71 consecutive patients with PPH requiring the urgent transfusion of three or more red blood cell (RBC) units, with or without transfusion of fresh frozen plasma (FFP) and/or platelets (PLT). Clinical records were then retrieved and examined for respiratory distress events. According to the 2004 consensus definition, cases of new-onset hypoxemia, within 6 hours after transfusion, with bilateral pulmonary changes, in the absence of cardiogenic pulmonary edema were identified as TRALI. If an alternative risk factor for acute lung injury was present, possible TRALI was diagnosed. RESULTS: Thirteen cases of TRALI and 1 case of possible TRALI were identified (overall incidence 19.7%). At univariate analysis, patients with TRALI received higher number of RBC, PLT and FFP units and had a longer postpartum hospitalization. Among the diseases occurring in pregnancy- and various pre-existing comorbidities, only gestational hypertension and pre-eclampsia, significantly increased the risk to develop TRALI (p = 0.006). At multivariate analysis including both transfusion- and patient-related risk factors, pregnancy-related, hypertensive disorders were confirmed to be the only predictors for TRALI, with an odds ratio of 27.7 ( 95% CI 1.27-604.3, p=0.034). CONCLUSIONS: Patients suffering from PPH represent a high-risk population for TRALI. The patients with gestational hypertension and pre-eclampsia, not receiving anti-hypertensive therapy, have the highest risk. Therefore, a careful monitoring of these patients after transfusions is recommended