What haematologists need to know about viscoelastic devices in bleeding patients

Abstract

The rationale for coagulation management in acute bleeding must be based on an understanding of the pathophysiological processes and functional assessment of the entire coagulation system leading to targeted replacement of platelets, fibrinogen and clotting factors or the use of anti-fibrinolytic agents. Standard coagulation assays such as prothrombin time and activated partial thromboplastin time are measures of clot initiation and do not test the entire cell based coagulation system only providing indirect correlation with the clinical picture in critical bleeding. Evidence is growing that viscoelastic assays, such as ROTEM or TEG are superior to standard coagulation tests in guiding critical bleeding coagulation management. ROTEM/TEG provides a quantitative global in vitro assessment of haemostasis with multiple end points reflecting the interaction between platelets, fibrinogen and clotting factors and fibrinolysis. The tests are sensitive to qualitative and quantitative differences in the factors which influences clot generation and stability. Normal results in the presence of ongoing bleeding have a high negative predictive value of surgical bleeding rather than that associated with coagulopathy. ROTEM/TEG provides useful tools for global assessment of haemostasis and hyperfibrinolysis and may be used to facilitate targeted, timely and appropriate use of blood components in trauma, surgical and obstetric patients.