Thromboelastography

Aka: Thromboelastography, Viscoelastic Assay, Rotational Thromboelastography, ROTEM, TEG, Viscoelastic Substances, Thromboelastography Panel

1. Indications
   1. Massive Hemorrhage related transfusions
      1. May assist in determining ratio of Red Blood Cell Transfusions to Fresh Frozen Plasma and Platelet Transfusion
2. Mechanism
   1. Whole blood assay of a blood's ability to clot based on viscoelastic blood properties
   2. As blood clot forms, analyzer detects resistance over time
      1. Analyzer plots measurized resistance over time in form of a graph
      2. Typically graph is plotted over a 20-30 minute period until maximal clot firmness
3. Interpretation
   1. Abnormal Clotting Time
      1. In early trauma Coagulopathy, often related to plasma related deficiencies
      2. In later trauma Coagulopathy, Fibrinogen deficiency may be treated with Cryoprecipitate or Fibrinogen
   2. Poor maximal clot firmness (poor maximal amplitude)
      1. Consider Platelet Transfusion
   3. Hyperfibrinolysis
      1. Typically assumed as a part of early trauma Coagulopathy, and Tranexamic Acid is given empirically
      2. May appear as abnormal clot breakdown over time (typically subtle in graph)
4. Labs: Bedside Viscoelastic Assay
   1. Thromboelastography (TEG)
   2. Rotational Thromboelastography (ROTEM)
5. Resources
   1. Shaydakov, Sigmon, Blebea (2019) Stat Pearls
      1. https://www.ncbi.nlm.nih.gov/books/NBK537061/
6. References
   1. Swaminathan and Hicks in Herbert (2020) EM:Rap 20(7): 1-2