A comparative study of viscoelastic hemostatic assays and conventional coagulation tests in trauma patients receiving fibrinogen concentrate.

BACKGROUND: Both thrombelastography (TEG) and rotational thromboelastometry (ROTEM) have been investigated for diagnosis of coagulopathy and guidance of resuscitation in trauma and surgery. Given similarities between the two systems, it is important to determine whether one is superior to the other and how comparable they are to conventional coagulation tests (CCTs). Therefore, we conducted a comparative study of functional fibrinogen and coagulation assays using TEG and ROTEM and CCTs to determine their capability to monitor coagulation profiles, diagnose coagulopathy and predict blood transfusion requirements in trauma patients.

METHODS: Blood samples were collected from 45 patients at admission and during 48-h hospitalization as part of a randomized control trial on early fibrinogen replacement in trauma. Functional fibrinogen (FF) TEG, ROTEM FIBTEM and EXTEM, and CCTs were performed and compared.

RESULTS: We found significant differences between the placebo and fibrinogen groups over hospitalization time in FF TEG MA, ROTEM CT, MCF and LI30. FF TEG MA and ROTEM FIBTEM MCF mirrored plasma fibrinogen profiles, reached a maximum difference between the two groups 1-3 h after fibrinogen administration. In comparison, CCTs detected minimal hemostatic changes by fibrinogen treatment. TEG and ROTEM showed various degrees of correlations with CCTs. TEG MA and ROTEM MCF provided better predictions for plasma and RBC transfusions than CCTs, but poor accuracy for cryoprecipitate transfusion. Both TEG and ROTEM well predicted hypofibrinogenemia (fibrinogen concentration < 1 g/L), but poorly detected coagulopathy (INR ≥ 1.2).

CONCLUSIONS: TEG and ROTEM detected increases in clot strength following early use of fibrinogen. ROTEM also detected changes in coagulation time and clot lysis. Both were better than CCTs for monitoring coagulation profiles and predicting transfusion requirements.