What is the role of viscoelastography in Intensive Care Unit (ICU) for assessing haemostasis?

From the Guidelines

Viscoelastography, including thromboelastography (TEG) and rotational thromboelastometry (ROTEM), is a crucial tool for managing hemostasis in ICU patients, as it provides real-time assessment of the entire coagulation process, allowing for targeted blood product administration and reduced unnecessary transfusions, as recommended by the latest European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1.

Key Points

• Viscoelastography helps identify specific coagulation defects, such as factor deficiencies, platelet dysfunction, and fibrinogen deficiency, guiding targeted therapeutic interventions 1.
• The technology is particularly useful in trauma, massive hemorrhage, liver transplantation, cardiac surgery, and obstetric hemorrhage, where timely and personalized hemostatic management is critical 1.
• Viscoelastography can reduce blood product usage by 20-50% compared to conventional coagulation tests, while providing faster results and more comprehensive coagulation assessment, ultimately improving patient outcomes 1.

Implementation

• Blood samples should be analyzed within 4-6 minutes of collection, with results available within 10-30 minutes, to ensure timely decision-making and intervention.
• The tests can identify hyperfibrinolysis, potentially requiring tranexamic acid, and guide the administration of cryoprecipitate or fibrinogen concentrate for fibrinogen deficiency.

Evidence-Based Recommendation

• The use of viscoelastography in ICU for hemostasis is supported by the latest European guideline, which recommends its use to quickly determine the type and degree of coagulopathy in individual patients, allowing for goal-directed therapeutic intervention 1.
• This approach can improve coagulation, reduce the need for transfusion of blood products, decrease post-traumatic multiorgan failure, length of hospital stay, and improve survival, as demonstrated in recent studies 1.

From the FDA Drug Label

Administer additional doses of 4 g in adults, 50 mg/kg body weight in adolescents 12 years of age and above, and 70 mg/kg body weight in children <12 years of age as needed to bleeding patients when plasma fibrinogen level is ≤200 mg/dL or thromboelastometry FIBTEM A10 is ≤10 mm (or equivalent values generated by other viscoelastic testing methods). Dosing may be adjusted depending on plasma fibrinogen levels or viscoelastic testing, severity of bleeding, body weight, or patient’s clinical condition Monitor the patient’s plasma fibrinogen level or the viscoelastic properties of the fibrin-based clot during treatment with FIBRYGA.

Viscoelastography in ICU for Haemostasis:

• Viscoelastography, such as thromboelastometry, can be used to guide the administration of fibrinogen in bleeding patients.
• The results of viscoelastic testing, such as FIBTEM A10, can be used to determine the need for additional doses of fibrinogen.
• The target plasma fibrinogen level and viscoelastic properties of the fibrin-based clot should be monitored during treatment with fibrinogen 2.
• Viscoelastic testing methods can provide equivalent values to FIBTEM A10, which can be used to guide dosing decisions 2.

From the Research

Use of Viscoelastography in ICU for Haemostasis

• Viscoelastography (VE) is an established method to identify coagulopathies in various disease processes, including trauma, anticoagulation reversal, liver disease, acute ischemic stroke, and acquired brain injuries 3.
• The use of thromboelastography (TEG) or rotational thromboelastometry (ROTEM) has been shown to reduce overall mortality and the need for blood products in bleeding patients, although the quality of evidence is graded as low due to the high risk of bias, heterogeneity, imprecision, and low event rate 4.
• Viscoelastic testing (VET) provides a rapid and comprehensive picture of whole blood coagulation dynamics and hemostasis that can be reviewed and evaluated at the point-of-care, with potential clinical applications in critical care, including ICU 5.
• The use of viscoelastic-based techniques to evaluate whole blood hemostasis has advanced substantially and is now more widespread, used commonly in intensive care units, with next-generation hemostasis monitoring devices being developed for use at the site of care 6.
• Thromboelastometry (ROTEM) and thrombelastography (TEG) are two of the most commonly used viscoelastic hemostatic assays, which have proven to decrease allogenic blood transfusions with cost reduction and possibly decrease mortality and morbidity in cardiac, trauma, and other bleeding patients 7.

Clinical Applications

• Viscoelastography can be used to guide haemostatic treatment in bleeding patients, including those in the ICU 4.
• The technology has a wide range of potential clinical applications, such as treating coagulopathies in liver disease and transplant surgery, critical care, as well as within obstetrical hemorrhage 5.
• Viscoelastic testing can provide a broad overview of hemostasis from clot formation to clot lysis, while highlighting the contribution of coagulation factors and platelets 5.

Limitations and Future Directions

• The quality of evidence for the use of viscoelastography in ICU for haemostasis is limited due to the high risk of bias, heterogeneity, imprecision, and low event rate 4.
• Further research is needed to validate the technology in some care settings and to provide high-grade evidence for its use in clinical practice 5.
• Next-generation hemostasis monitoring devices are being developed for use at the site of care, which may improve patient care in the future 6.