INR-Triggered Transfusion In GI Bleeders From ER

Overview

Transfusion-related acute lung injury (TRALI) is the most common cause of transfusion-related morbidity and mortality in the United States. It is very common and often unrecognized in the critically ill with the greatest incidence occurring in bleeding patients with liver disease. Plasma is the most blood component associated with this deadly complication and therefore patients with liver disease who frequently receive transfused plasma are at increased risk. The optimal plasma transfusion strategy for bleeding patients with liver disease is unknown and the investigators will evaluate this clinical question in a small pilot randomized controlled trial. The invstigators hypothesize that targetting a more restrictive INR Target (2.5) vs. an INR Target (1.8) will result in less hypoxemia, a TRALI surrogate without increasing bleeding complications.

Advances in the understanding of the coagulation imbalance in liver disease have experts questioning the clinical efficacy of current plasma transfusion practices in patients with liver disease. Having recently discovered a large previously unrecognized risk (TRALI) of plasma transfusion in this patient population, the investigators now believe the current clinical transfusion paradigm under-recognizes risk and overvalues the benefit of plasma transfusion in bleeding patients with liver disease. Though experts have recommended more judicious use of plasma, clinical practice remains variable. Transfusion triggers and thresholds are often arbitrarily set based on conventional coagulation studies and evidence to guide clinicians on plasma dosing required to achieve these laboratory thresholds does not exist. The investigators hypothesize that a restrictive plasma transfusion strategy in critically ill chronic liver disease patients with acute gastrointestinal bleeding will decrease a surrogate measure of TRALI without increasing bleeding complications (figure 1). With the collaborative support of the pulmonary/critical care, hepatology, and transfusion medicine services, the investigators will conduct a randomized controlled trial comparing a restrictive versus liberal strategy of plasma transfusion in bleeding patients with liver disease. In addition, investigators will refine and validate our plasma transfusion dosing algorithm so clinicians will have the tools to appropriately dose plasma to reach evidence-based transfusion targets. 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.