Influenza A (H1N1): the first hit for transfusion-related acute lung injury?

Abstract

Introduction Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related fatalities [1]. A two-hit hypothesis has been proposed for TRALI. The first hit is underlying patient factors, resulting in adherence of primed neutrophils to the pulmonary endothelium, such as severe pneumonia due to influenza A H1N1. The second hit is caused by mediators in the blood transfusion that activate the endothelial cells and pulmonary neutrophils, resulting in capillary leakage and subsequent pulmonary edema [2]. TRALI is a clinical diagnosis with the following criteria: acute onset within 6 hours of blood transfusion, PaO2/FIO2 ratio <300 mmHg, or worsening of the P:F ratio, bilateral infiltrative changes on chest radiograph, no sign of hydrostatic pulmonary edema (pulmonary arterial occlusion pressure