Viscoelastic Hemostatic Tests and Fibrinogen Concentrations in Trauma

Abstract

Thrombelastography (TEG) and rotational thromboelastometry (ROTEM) are used to diagnose trauma-induced coagulopathy, fibrinogen deficiency, and guide fibrinogen transfusion in trauma, as well as to study the hemostatic effect of fibrinogen supplementation. We reviewed the clinical applications of TEG and ROTEM focusing on two functional fibrinogen (FF) tests, TEG FF and ROTEM FIBTEM, for assessing and guiding fibrinogen replacement in trauma patients. ROTEM FIBTEM, the standard FF test, measures clot amplitude. In contrast, while TEG FF, which is considered the standard FF test, also measures clot amplitude, other TEG tests, e.g., kaolin and rapid TEG, measure several coagulation parameters (maximum amplitude, K value, and angle α) to assess FF. Some confounding factors (e.g., hematocrit, factor XIII, and resuscitation fluids) need to be considered when interpreting the hemostatic effect of fibrinogen replacement measured by TEG and ROTEM. Different cutoff values for TEG and ROTEM parameters, particularly for maximum clot firmness (MCF) in FIBTEM, have been used for fibrinogen replacement. The dosage of fibrinogen replacement can be calculated based on the desired increment in the FIBTEM MCF or plasma fibrinogen level. In addition, we compared the clinical performance of the two FF test systems; the results were correlated but not interchangeable.