1. Thromboelastography as an Adjunct Tool to Assess Coagulation Disturbances in Isolated Traumatic Brain Injury Patients Asaph Nini MD 1, David Livingstone MD 1, Elena Mishuk MD 1, Alexander Kogan MD 2, and Eran Segal MD 3 1 General ICU, Department of Anesthesiology and Intensive Care, Sheba Medical Center, 2 Department of Cardiac Surgery, Sheba Medical Center, 3 Intensive Care Unit, Assuta Medical Center, Tel Aviv, Israel Introduction: Coagulation disorders are common after traumatic Brain Injury (TBI), may contribute to morbidity and mortality, and have prognostic implications (1). These disorders are complex and dynamic over time, making clinical evaluation of coagulation status of the patients difficult (2). Thromboelastography (TEG) has been suggested as a tool for rapid assessment of such states. TEG is an ex vivo test of clot formation and lysis, providing a holistic assessment of clot evolution over time, and clot strength. A 360  L sample of blood is introduced into a bin that is then rotated around a torque sensor. As clot forms, stronger forces are applied to the sensor, until maximal strength is reached. Later, as fibrinolytic processes take over, clot strength gradually declines. Several parameters are useful in basic TEG analysis. The time to the beginning of force generation, termed R, reflects activation of the coagulation cascade. The rate of increase in strength, measured as angle , reflects fibrinogen activity. The maximal strength (MA), reflects platelet function, and the rate of decrease in strength over 30 minutes (LY30), as percent, reflects fybrinolysis. The aim of this pilot study is to survey the contribution of Thromboelastography in the assessment of coagulation status in patients with isolated TBI. Methods: Existing TEG database was surveyed for tests from patients with isolated TBI. Tests were examined for signs of bleeding tendency or hypercoagulability. Results: Ten patients with isolated traumatic brain injury were evaluated using TEG. Reasons for tests included workup for suspected bleeding, screening for hypercoagulable states, or planned invasive procedures. Three of these patients showed increased LY30, indicating thrombolysis, and two patient showed prolongation of the R value, indicating prolonged clotting time. Two patients showed increased Maximal Amplitude (MA), indicating a hypercoagulable state. Discussion: Coagulation disorders in TBI patients, causing both hypo and hyper coagulation, can be revealed by TEG. Limitations of current study: This is a pilot survey, with consequent limitations, particularly sample size, timing of TEG tests and follow up tests, systematic comparison to standard tests, and effect of test results on clinical decision making and outcome. Additionally, study population should be expanded to multitrauma patients who also suffered TBI. It is important to note that standard TEG, used in this study, does not reflect disorders of platelet activation. Conclusions: Thromboelastography is a useful adjunct tool in the assessment of coagulation status in isolated TBI patients, and may help in clinical decision making in such patients. Further work, relating thromboelastography results, prognosis and management are warranted. References: Harhangi B.S., Kompanje F.J.O., Leebeek F.W.G. and Maas A.L.R. Acta Neurochir (Wien) 2008 150: 165-175 Stein S.C. and Smith D.H. Neurocrit Care 2004 1: 479- 488 Salooja N and Perry D.J. Blood Coagulation and Fibrinolysis 2001 12:327-337 Fig I: Normal thromboelastogram Fig II: Top: TEG showing a prolonged K value, flat angle and low Max Amplitude, indicating a combined disorder of coagulation factors, Fibrinogen and platelets. Middle: TEG showing increased LY30, indicating enhanced fibrinolysis. Bottom: Same patient 24 hrs later, after treatment with Tranexamic acid. Hypercoagulability2/10 Increased Fibrinolysis3/10 Hypocoagulability2/10 Normal Test3/10 Table I: Summary of Results Financial Disclosure: None of the authors report any conflict of interests