Thromboelastography Flashcards
Most of the strength of a clot comes from
Platelets
75-85%
A thromboelastography analyzes measures the ability of a clot to
Mechanically impede hemorrhage
What produces the final clot?
Fibrin strand and activated platelets which form fibrin-platelet bonding
During vascular recovery, the clot gradually
Dissolves
Look at all the pictures
Do it now
R measures the time of latency between time that blood was placed in analyzer to
Initial fibrin formation
What does a longer R mean?
It takes longer than normal for the first fibrin strand to be formed
Represents a factor deficiency
An elongated R can be corrected using
Fresh frozen plasma
Alpha measures the _________ of fibrin build up and crosslinking
Rapidity
The speed of clot strengthening
K measures the rapidity of
Reaching a certain clot strength
Where is the clot strength measured?
20 mm amplitude
A direct function of the maximum dynamic properties of fibrin and platelet bonding via GPIIb/IIIa and represents the ultimate strength of the fibrin clot
Maximum Amplitude (MA)
Determines the rate of clot build up
Fibrinogen
Enables cross linking
Factor XIII (rarely deficient) Platelets, to a lesser extent
An elongated K and reduced alpha can be corrected by administering
CRYO (contains both platelets and factor XIII)
Small MA represents ______ and can be corrected by
Thrombocytopenia (platelet dysfunction)
Administering platelets
There is a compensatory effect between
Fibrinogen level and platelets
Platelets are affected by most, if not all
Cardiac surgical procedures
So with small MA, infusion with platelets alone will correct the coagulopathy
LY30 measures?
Stability of the clot
Rate of amplitude reduction 30 min after MA
A linear combination of R, alpha, K, and MA is given by
Coagulation Index (CI)
Mechanical bleeding is due to _______ and shows _______ TEG parameters
Vascular injury
Normal
Pathophysiological bleeding is an imbalance between anticoagulant and _____ of the hemodynamics system
Prothrombotic
Hyperfibrinolysis is represented by
LY30 greater than 7.5%
Can be corrected by antifibrinolytic drugs
Probable causes of bleeding and their treatments
Vessel injury: suture
vWF deficiency: DDAVP
Presence of platelet inhibitor: run platelet mapping
A bleeding patient with an abnormally long R value probably has
An enzymatic pathway abnormality
Can also cause abnormalities in angle and MA
Inhibition or dysfunction of platelet receptors
Activation
Inhibition or dysfunction of GPIb receptor, preventing adhesion of platelet to endothelium
Adhesion
Inhibition or dys of GPIIb/IIIa receptors preventing the development of platelet plug
Aggregation
Inhibition or dys of of secretory pathway resulting in reduced platelet activation
Secretion
Reduction of thrombin generation on platelet surface
Procoagulant activity
