Thrombelastography (TEG) and thrombelastometry (ROTEM) represent two in-vitro methods to measure and to visualize the viscoelastic properties of a clot. Both methods provide information on the speed of coagulation initiation, kinetic of clot growth, clot strength and clot breakdown and enable the differentiation between a global coagulation factor deficiency, a specific fibrinogen deficiency, a heparin-induced coagulopathy and hyperfibrinolysis in diffusely bleeding patients. On the basis of TEG/ROTEM results coagulation therapy may be guided towards “goal-directed” administration of coagulation factors (fibrinogen, PCC), protamin or antifibrinolytics. As a result, transfusion of fresh frozen plasma (FFP), platelet and red blood cell concentrates should be reduced with all the positive consequences for patient morbidity and mortality as well as costs.
In their metanalysis of 9 RCTs including 776 patients undergoing cardiac surgery or liver transplantation, Afshari et al. report a stastistically significant but only moderate reduction of blood loss (85 mL) in patients having been monitored with TEG/ROTEM. More important seemed the 40% reduction of patients transfused with a combination of FFP and platelets. When examined separately there was no significant reduction of FFP or platelet transfusion by TEG/ROTEM monitoring. A beneficial effect of TEG/ROTEM on survival could not be detected. Adverse effects related to TEG/ROTEM could not be identified.
The authors conclude that at the present time, due to the lack of data, there is only weak to moderate evidence to support the use of TEG/ROTEM in cardiac surgery and liver transplantation.
– Oliver Habler