TEG- Exam 3 Flashcards by Briana Lieberman

What three processes are involved in hemostasis?

Activation
Clot formation
Clot lysis

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Clot: Platelet-fibrin network

Platelets form plug
Clotting factors reinforce platelets
Fibrin acts as a glue
Clot strength

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What is a clot composed of?

Platelets 80-90%

Fibrin 10-20%

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What tests are available for component measurements?

PT/INR
PTT
Fibinogen concentration
Platelet Count

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PT/INR Test

Measures extrinsic clotting (VIIa, Xa, IIa)

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PTT

measures intrinsic clotting (XIIa, Xia, iXa, IIa)

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Measurement of component interactions

TEG (shows the net effect “whole picture” of hemostasis

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What is TEG?

A whole blood hemostasis analyzer

Point of care test

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What is TEG?

A whole blood hemostasis analyzer

Point of care test

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How does TEG work?

Cup oscillates
Pin is attached to torsion wire
Clot binds pin to cup
Degree and magnitude of pin motion are functions of the clot kinetics and mechanical properties
System generates a hemostasis profile

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How does TEG work?

Cup oscillates
Pin is attached to torsion wire
Clot binds pin to cup
Degree and magnitude of pin motion are functions of the clot kinetics and mechanical properties
System generates a hemostasis profile

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time of latency from the time that the blood was placed in the TEG analyzer until the initial fibrin formation

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Alpha

The alpha value measures the rapidity (kinetics) of fibrin build-up and corss-linking, that is, the speed of clot strengthening

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K time is a measure of the rapidity to reach a certain level of clot strength

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Max amplitude, direct function of the maximum dynamic properties of firbin and platelet bonding via GPIIb/IIIa and represents the ultimate strength of the fibrin clot

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coagulation index is linear combination of the above parameters

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LY30

rate of amplitude reduction 30 minutes after MA. This measurement gives an indication of the stability of the clot

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time of latency from the time that the blood was placed in the TEG analyzer until the initial fibrin formation; reaction time (time to clot formation)

Alpha

The alpha value measures the rapidity (kinetics) of fibrin build-up and cross-linking, that is, the speed of clot strengthening; speed of fibrin accumulation

K time is a measure of the rapidity to reach a certain level of clot strength; time elapsed until clot reaches a fixed strength

Max amplitude, direct function of the maximum dynamic properties of firbin and platelet bonding via GPIIb/IIIa and represents the ultimate strength of the fibrin clot; highest vertical amplitude of TEG tracing

coagulation index is linear combination of the above parameters

LY30

rate of amplitude reduction 30 minutes after MA. This measurement gives an indication of the stability of the clot; % of amplitude reduction 30 min after its max

LY30

rate of amplitude reduction 30 minutes after MA. This measurement gives an indication of the stability of the clot; % of amplitude reduction 30 min after its max

R Likely Variable

Coagulation Factors

Alpha Likely Variable

Fibrinogen

K LIkely Variable

Fibrinogen

MA Likely Variable

Platelets

Ly30 likely variable

Fibrinolysis

Ly30 likely variable

Fibrinolysis

TEG Assays

Standard (Kaolin) Rapid TEG Heparinase Platelet Mapping

Standard (Kaolin)

Uses parameters listed above

Rapid TEG

uses tissue factor in place of kaolin to speed up the rxn R-value is replaced by TEG-ACT value Other parameters the same

Heparinase

Use on bypass or post bypass alongside a standard TEG

Platetlet Mapping

Determines to what degree platelet function is inhibited due to pharmacological inhibition of either the arachidonic acid (AA) or ADP pathways AA: Aspirin ADP: Clopidrogel Run alongside a standard TEG and a TEG with added AA or ADP Calculates platelet inhibition as a percentage

Platelet Mapping

What does platelet mapping measure?

Measures the effect of antiplatelet agents on platelet function Measures the patient's maximum platelet function as a reference point Measures the percentage of inhibition relative to the patient's reference point

What does platelet mapping measure?

Platelet Mapping: What drugs are monitored?

Antiplatelet Drugs - ADP receptor inhibitors - Arachidonic acid pathway inhibitiors - GPIIb/IIIa inihibitors

ADP receptor inhibitors

clopidogrel, ticlopidine

Arachidonic acid pathway inihibitors

aspirin

GPIIb/IIIa inhibitors

abciximab, tirofiban, eptifibatide

Rotational Elastometry (ROTEM)

Stationary cup, rotating spindle Clot impedes rotation of the pin Additional tests available