The development of TRALI is believed to require two pathophysiologic events. First, a pro-inflammatory stimulus, such as sepsis, leads to exposure of endothelial surface adhesion proteins and consequent capture of polymorphonuclear leukocytes (PMNs) within the pulmonary microvasculature. Second, these adherent PMNs are activated by mediators within transfused blood components, leading to neutrophilic inflammation and TRALI. Emerging evidence suggests that the process of neutrophil adhesion in the lung involves degradation of the endothelial glycocalyx, a thin layer of glycosaminoglycans (GAGs) lining the vascular lumen(S). In mice, sepsis results in pulmonary glycocalyx loss, neutrophil adhesion and subsequent development of ALI(S). Glycocalyx degradation is also associated with organ injury in humans, as evidenced by an increase in circulating GAG fragments (e.g. heparinoids) in septic shock. Circulating heparinoids can be detected quickly and accurately by a point of care heparinase-I modified thromboelastogram (TEG) study26-27. Detection of heparinoids by TEG may therefore indicate pulmonary microvasculature propensity for PMN adhesion (first event) and be utilized as a predictive biomarker for TRALI. Restrictive plasma transfusion strategies could then be individualized to high risk patients to decrease the probability of a second event resulting in the clinical syndrome of TRALI. In conjunction with the clinical trial, investigators will perform a translational observational study to assess whether detection of systemic heparinoids predict the subsequent development of a TRALI surrogate, post-transfusion hypoxemia. These clinical studies will pave the way for larger clinical trials guiding future plasma transfusion practice and decreasing the significant TRALI burden in the critically ill.