An in vitro evaluation of standard rotational thromboelastography in monitoring of effects of recombinant factor VIIa on coagulopathy induced by hydroxy ethyl starch

The study was performed in vitro on healthy volunteers. Prothrombin time (PT) and ROTEG analysis were performed after dilution with 33% hydroxy ethyl starch and also after addition of rFVIIa to the diluted blood.PT was impaired with INR changing from 0.9 before dilution to 1.2 after dilution while addition of rFVIIa to diluted blood lead to an overcorrection of the PT to an International Normalized Ratio (INR) value of 0.6 (p = 0.01). ROTEG activated with the contact activator ellagic acid was impaired by hemodilution (p = 0.01) while addition of rFVIIa had no further effects. ROTEG activated with tissue factor (TF) was also impaired by hemodilution (p = 0.01) while addition of rFVIIa lead to further impairment of the coagulation (p = 0.01).The parameters affected in the ROTEG analysis were Clot Formation Time and Amplitude after 15 minutes while the Clotting Time was unaffected. We believe these effects to be due to methodological problems when using standard activators of the coagulation in the ROTEG analysis in combination with rFVIIa.Patients undergoing massive hemorrhage experience dilutional coagulopathy with crystalloid and/or colloid resuscitation. If hemorrhage progresses, packed red cells (RBC) are transfused together with crystalloids and/or colloids. Regarding the coagulation this is not optimal, and the patients often develop a dilutional coagulopathy, sometimes worsened by hypothermia. In addition a coagulopathy caused by the administration of dextrane or hydroxy ethyl starch (HES) may be induced. The common approach to this is transfusion of fresh frozen plasma (FFP) and platelets, but bleeding might continue, with often fatal outcome. Prophylactic use of fresh frozen plasma (FFP) or platelet transfusion is not proven beneficial to prevent hemorrhage in massively transfused patients[1]. Hemorrhage, complicated by the development of coagulopathy, is therefore still the major cause of death in trauma patients arriving alive in the hospital.[2,3].A novel