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Logistics and Sponsor:
Sponsor: None
EPA Addressed:
#8 Perioperative care of the critically ill surgery patient.
#18: Evaluation and initial management of a patient presenting with blunt or penetrating trauma.
Goals and Objectives
Goals and Objectives
Understand the clotting cascade and the fibrinolytic system
Understand the differences between ROTEM, TEG, and standard coagulopathy labs
Understand how to interpret and treat abnormalities in TEG and ROTEM results
Clinical Scenarios
Clinical Scenarios
Scenario 1
Scenario 1
A young adult presents after blunt trauma with ongoing hemorrhage and hypotension. Initial labs show elevated INR and low platelets. TEG is performed on arrival, revealing prolonged reaction time (R) and decreased maximum amplitude (MA).
Note: The American Association for the Surgery of Trauma recommends TEG-guided resuscitation as an adjunct to conventional damage control resuscitation, noting that TEG can reduce unnecessary transfusions and may improve outcomes in trauma patients, although recent multicenter data show no difference in major outcomes compared to conventional testing.
Scenario 2
Scenario 2
A young adult presents after blunt trauma with ongoing hemorrhage and hypotension. Initial labs show elevated INR and low platelets. TEG is performed on arrival, revealing prolonged reaction time (R) and decreased maximum amplitude (MA).
Note: The American Association for the Study of Liver Diseases and the American Gastroenterological Association both highlight that TEG provides a more accurate assessment of bleeding risk in cirrhosis than INR or platelet count, and TEG-guided transfusion strategies significantly reduce blood product use without increasing bleeding risk.
Scenario 3
Scenario 3
A postoperative patient develops bleeding after receiving a bolus of unfractionated heparin for a DVT. A standard TEG reveals a significantly prolonged R time, and a heparinase-modified TEG shows a normal R time.
Rotem System
Rotem System
Werfen
TEG 6s System
TEG 6s System
A video of the TEG 6S can also be found here:
A video of the TEG 5000 can be found here:
The viscosity of the sample does not change during the initial phases clotting cascade activation, as no platelets have been cross-linked with fibrin yet. This is why the R time (reaction time) is stable and normalized to a baseline amplitude. The R time is dependent on how many factors are around to go through the cascade.
Once platelets begin to cross-link by converting fibrinogen to fibrin, the viscosity of the blood sample begins to change. This manifests as an increase in the maximum amplitude (MA) of the plot. The rate of cross-linking is related to the amount/abundance of fibrinogen available.
A TEG 5000 (the older TEG) reports R times, K times (and angles), MA, and LY30.
A TEG 6s global hemostasis with lysis (the main order we use in the trauma bay) runs 4 samples at once to tease out how heparin, fibrin, and platelets all contribute to the plot. It will report an R time from the citrated kaolin sample, a Citrated Rapid TEG-MA (CRT), a Citrated Functional Fibrinogen (CFF) from the platelet inhibited sample, and a LY30. As the platelets are inhibited and do not contribute to clot strength in the CFF-MA, the strength of that clot is from fibrin. The difference between the CRT-MA and the CFF-MA represents the strength of the clot associated with platelets. So, a low CRT-MA may be from low fibrinogen OR low/inhibited platelets. You have to look at the CFF (fibrin clot) and the difference between the CRT and CFF (platelet contribution) to determine which product to needed to fix a low CRT.
TEG 6s with platelet mapping is used to determine if a patient has any Aspirin or Plavix platelet inhibition. It does not report an R time or an LY30, so it is not a replacement for the TEG 6s global hemostasis with lysis in a trauma patient. It is an additional order in select patients.
TEG/ROTEM in Trauma
TEG/ROTEM in Trauma
How TEG/ROTEM is used in trauma.
Simulators
Simulators
TEG and TEG 6s Simulator
TEG and TEG 6s Simulator
Learn how to read and interpret the graphs! Values are illustrative and not meant for medical decision making. Made by Eric Petersen
IV Flow Rate Simulator
IV Flow Rate Simulator
Learn which access you need in an emergency and why! Values are illustrative and not meant for medical decision making. Made by Eric Petersen
Quiz Questions
Quiz Questions
In a standard TEG, what does the R time represent, and what does a prolonged R time suggest?
R time is the latency from test start until initial fibrin formation (clot amplitude of 2 mm). A prolonged R time suggests a deficiency in clotting factors or the presence of anticoagulants.
What does the K time measure in TEG, and what does a prolonged K time indicate?
K time is the time from clot amplitude of 2 mm to 20 mm, reflecting the speed of clot strengthening. A prolonged K time suggests low fibrinogen levels or impaired fibrin cross-linking.
In TEG, what does the α (alpha) angle represent?
The α angle reflects the rate of fibrin build-up and cross-linking, influenced by fibrinogen concentration and function. A low α angle suggests hypofibrinogenemia.
What does Maximum Amplitude (MA) measure, and what are the main contributors?
MA measures the maximum clot strength, determined by platelet function and fibrinogen. Low MA can be due to thrombocytopenia, platelet dysfunction, or low fibrinogen.
What does LY30 indicate in TEG?
LY30 is the percentage decrease in clot amplitude 30 minutes after MA, reflecting fibrinolysis. High LY30 suggests hyperfibrinolysis.
In TEG 6s Global Hemostasis with Lysis, what channels give R, CRT, and CFF respectively?
Citrated Kaolin (CK) — Gives R time
Citrated Rapid TEG (CRT) — Gives combined platelet + fibrin MA
Citrated Functional Fibrinogen (CFF) — platelet inhibited well that gives fibrin MA
How do you determine platelet contribution to clot strength in TEG 6s?
Subtract the CFF-MA (fibrin clot strength) from the CRT-MA (total clot strength). The difference represents platelet contribution.
If CRT-MA is low but CFF-MA is normal, what is the likely problem?
Platelet deficiency or dysfunction.
If both CRT-MA and CFF-MA are low, what is the likely problem?
Low fibrinogen levels.
What is the role of TEG 6s Platelet Mapping?
It assesses platelet inhibition from antiplatelet agents like aspirin or clopidogrel. It does not measure R time or LY30, so it’s not a replacement for Global Hemostasis in trauma.
Why might TEG/ROTEM be preferred over PT/INR in trauma resuscitation?
They provide a dynamic, real-time assessment of clot formation, strength, and breakdown, guiding targeted transfusion therapy more effectively than static coagulation labs.
What product would you give for:
Prolonged R time? A low α angle? A low MA with normal CFF-MA?A high LY30?
Prolonged R time → Fresh Frozen Plasma (FFP)
Low α angle or high K → Cryoprecipitate
Low MA with normal CFF-MA → Platelets
High LY30 → Antifibrinolytics (e.g., TXA)
Checklists
Checklists
Read through the provided resources and gain an understanding of the clotting cascade and the fibrinolytic system.
Understand the limitations of standard clotting labs such as PT/INR, especially in liver patients.
Watch the videos to understand physically how ROTEM and TEG systems work to better understand their outputs.
Use the simulators to better understand IV flow rates during emergency resuscitation as well as classical TEG and TEG 6s graph analysis.
Express an understanding of how to treat abnormalities in TEG and ROTEM results
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