S. Tejiram1, K. Brummel-Ziedins3, T. Orfeo3, S. Butenas3, B. Hamilton2, J. Marks2, L. Moffatt2, J. Shupp1,2 1MedStar Washington Hospital Center,The Burn Center, Department Of Surgery,Washington, DC, USA 2MedStar Health Research Institute,Firefighters’ Burn And Surgical Research Laboratory,Washington, DC, USA 3University Of Vermont,Department Of Biochemistry,Colchester, VT, USA
Introduction: While a body of literature exists on coagulopathy in trauma patients, understanding of abnormal coagulation in burn patients is limited. Studies have shown alterations in antithrombin, protein C and S levels after burn, but controversy remains over whether burn injury induces coagulopathy. There is no consensus on whether burn patients with variable injury severity are at risk for hyper- or hypocoagulation. Coagulation is a complex process that is frequently assessed only by laboratory values such as PT, PTT, and INR. These measurements do not account for clotting factor dynamics or clot characteristics. Real time assessment of a patient’s coagulation profile may help clinicians better understand the pathophysiology underlying abnormal coagulation in burn patients. Here, we monitored clotting factor levels in a pilot group of burn patients for 96 hours after admission to study potential perturbations in the coagulation system and help elucidate potentially meaningful dynamics in coagulation after burn injury not indicated by INR alone.
Methods: Nine thermally injured patients with total body surface area injuries of 25% or greater who presented to a verified burn center between 2013 and 2014 were included for analysis. Citrated plasma was collected at admission and at regular intervals over a 96 hour period. Clinical laboratory information, specifically PT, PTT, and INR, collected over the same time was compared to levels of factors II, IIa, V, VII, VIII, IX, IXa, X, XI, XIa, antithrombin, and tissue factor pathway inhibitor measured in plasma.
Results: Of the patients profiled, 4 died and 5 survived. Seven patients had factor VIII levels beyond the upper limit of normal range upon admission. Four of these had factor VIII levels 2-3 fold higher than normal. Over the subsequent 24 hours, all patients experienced an initial decrease of factor VIII levels to normal ranges before increasing again above the normal range. Factor IX was also elevated approximately 1.5 times normal levels upon admission in all patients and remained above normal range for all but 2 patients. Conversely, factor VII levels decreased below normal ranges for 3 patients after 24 hours. Only 4 patients had antithrombin levels in normal range upon admission and all patients had antithrombin levels below normal range shortly thereafter for the subsequent 96 hours. Three patients showed an increase in INR and PTT beyond normal range. Clinical laboratory values of INR and PTT remained within normal limits (INR < 1.3 and PTT 23-45s) for all other patients during this 96 hour period.
Conclusion: Dynamic changes in clotting factor levels follow immediately after thermal injury that may not be detected by monitoring of INR and PTT alone. These changes may be important in early identification of coagulopathy in this patient population, which to date is poorly characterized. Further study is warranted to explore the scope of abnormal coagulation in burn patients.