How to manage a high Clotting Rate Time (CRT) on a Thromboelastography (TEG)?

Management of High Clotting Rate Time (CRT) on Thromboelastography (TEG)

To correct a high Clotting Rate Time (CRT) on TEG, administer fibrinogen concentrate or cryoprecipitate, and consider fresh frozen plasma (FFP) if fibrinogen products are unavailable. 1

Understanding High CRT on TEG

A high Clotting Rate Time (also called R time or Reaction time) on TEG indicates delayed clot initiation, suggesting a deficiency in clotting factors. This parameter represents the time from the start of the test until initial fibrin formation begins.

• High CRT/R time indicates hypocoagulability in the initial phase of clotting, often due to coagulation factor deficiencies or the presence of anticoagulants 1, 2
• Normal coagulation requires adequate levels of clotting factors, which may be depleted in trauma, surgery, or critical illness 1
• TEG provides real-time assessment of comprehensive thrombostatic function, analyzing both enzymatic and platelet components of clot formation 3

First-Line Interventions

Fibrinogen Replacement

• Administer fibrinogen concentrate (first choice) or cryoprecipitate to restore clotting factor levels 1
• Target fibrinogen levels of at least 1.5-2.0 g/L in bleeding patients 1
• Fibrinogen is often the first coagulation factor to reach critically low levels during major bleeding 1

Fresh Frozen Plasma (FFP)

• If fibrinogen concentrate or cryoprecipitate is unavailable, administer FFP 1
• Use FFP when PT/aPTT is >1.5 times normal control 1
• Consider a FFP:RBC ratio of at least 1:2 in massive transfusion scenarios 1
• Note that FFP contains only ~70% of normal levels of clotting factors 1

Additional Management Considerations

Platelet Management

• Maintain platelet count >50,000/mm³ for patients with life-threatening hemorrhage 1
• Consider higher platelet counts for patients requiring neurosurgery or with traumatic brain injury 1
• Include platelets in a balanced transfusion approach (RBC:Plasma:Platelets at 1:1:1 ratio) during initial massive transfusion 1

Monitoring and Optimization

• Continue to monitor TEG parameters to guide ongoing treatment 1, 2
• Target a prothrombin time (PT)/activated partial thromboplastin time (aPTT) of <1.5 times normal control 1
• Consider the patient's underlying condition when interpreting TEG results, as baseline abnormalities may be present in critical illness even without bleeding 2, 4

Special Considerations

• In patients with liver disease, standard coagulation tests may not accurately reflect hemostatic function; TEG may provide more valuable information 1
• Patients on anticoagulant medications will require specific management approaches based on the anticoagulant used 1
• Hypercoagulability (opposite of high CRT) is common in certain conditions like COVID-19, pregnancy, and some ICU patients, requiring different management 2, 5, 4

Pitfalls to Avoid

• Do not rely solely on conventional coagulation tests (PT, aPTT) as they may not correlate well with clinical bleeding or TEG parameters 1, 2
• Avoid excessive correction of coagulation parameters, as this may lead to thrombotic complications 3, 5
• Remember that TEG may be poorly sensitive to fibrinolysis in some cases, so integrate clinical assessment with laboratory findings 1
• Do not delay treatment while waiting for laboratory results in cases of severe bleeding 1

By following this approach, you can effectively correct high CRT on TEG and improve coagulation status in patients with bleeding or at risk of bleeding.