test 5

Question 1

Clot strength

Answer 1

• Platelets 80%-90%

* Fibrin 10%-20%

Question 2

Component Measurements:
PT/INR:
PTT:

Answer 2

• PT/INR: measures extrinsic clotting (VIIa, Xa, IIa)
• PTT: measures intrinsic clotting (XIIa, XIa, IXa, IIa)
• Fibrinogen concentration
• Platelet Count (doesn’t tell you function of platelets)

Question 3

What is thromboeleastography (TEG)

Answer 3

• A whole blood hemostasis analyzer

* Point of care test

Question 4

How does TEG work

Answer 4

• 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

Question 5

TEG parameters: R

Likely variable

Answer 5

• Reaction time (time to clot formation)

- Likely variable: Coagulation factors

Question 6

TEG parameters: Alpha

Answer 6

• Speed of fibrin accumulation

- Likely variable: Fibrinogen

Question 7

TEG parameters: K

Answer 7

• Time elapsed until clot reaches a fixed strength

- Likely variable: Fibrinogen

Question 8

TEG parameters: MA

Answer 8

• Highest vertical amplitude of TEG tracing

- Likely variable: Platelets

Question 9

TEG parameters: LY30

Answer 9

• % of amplitude reduction 30 minutes after its maximum

- Likely variable: fibrinolysis

Question 10

Elongated R - Thrombin formation abnormalities
1. Possible cause of
imbalance?
2. Possible Etiologies?
3. Common Treatments?

Answer 10

Possible cause of
imbalance:
        • Slow enzymatic reaction
Possible Etiologies
        • Factor deficiency/dysfunction
        • Residual heparin
Common Treatments:
        • FFP
        • Protamine

Question 11

Low alpha angle - Fibrinogen abnormalities
1. Possible cause of
imbalance?
2. Possible Etiologies?
3. Common Treatments?

Answer 11

Possible cause of imbalance
• Slow rate of fibrin formation
Possible etiologies
• Low fibrinogen levels or function
• Insufficient rate/amount of thrombin generation
• Platelet deficiency/dysfunction
Common Treatments
• FFP
• Cryoprecipitate

Question 12

Low MA - Platelet function abnormalities
1. Possible cause of
imbalance?
2. Possible Etiologies?
3. Common Treatments?

Answer 12

Possible causes:
        • Insufficient platelet-clot formation
Possible etiologies
        • Poor platelet function
        • Low platelet count
        • Low fibrinogen levels or function
Common treatments:
        • Platelets

Question 13

High MA - Platelet function abnormalities
1. Possible cause of
imbalance?
2. Possible Etiologies?
3. Common Treatments?

Answer 13

Possible causes:
        • Excessive platelet activity
Possible etiologies
        • Platelet hypercoagulability
Common Treatments
        • Antiplatelet agents

Question 14

Pictures of possible tracings

Answer 14

• Look at them

Question 15

TEG assays - Standard (kaolin)

Answer 15

• Use normal parameters

Question 16

TEG assays - Rapid TEG

Answer 16

• Uses tissue factor and kaolin to activate extrinsic and intrinsic pathways
• R-value is replaced by TEG-ACT value
• Other parameters the same
• Increased speed can save valuable time

Question 17

TEG assays - Heparinase

Answer 17

• Used on bypass or post bypass alongside a standard TEG

Question 18

TEG assays - Platelet Mapping

Answer 18

• Determines to what degree platelet function is inhibited due to pharmacological inhibition of either the arachidonic acid (AA) or adenosine diphosphate (ADP) pathways
  * AA: Aspirin
  * ADP: Clopidogrel
  * Run alongside a standard TEG and a TEG with added AA or ADP.
  * Calculates the percentage of inhibition relative to the patient’s maximum platelet function

Question 19

What drugs are monitored during platelet mapping

Answer 19

• Antiplatelet Drugs
  * ADP receptor inhibitors
  * Examples: clopidogrel, ticlopidine
  * Arachidonic acid pathway inhibitors
  * Example: aspirin
  * GPIIb/IIIa inhibitors
  * Examples: abciximab, tirofiban, eptifibatide

Question 20

Why platelet mapping

Answer 20

• Individual response to antiplatelet drugs determines clinical outcome
• Knowing percent of platelet inhibition is insufficient to determine therapeutic efficacy
• Knowledge of maximum platelet function is also required as a reference point

Question 21

Rotational Elastometry (ROTEM)

Answer 21

• STATIONARY CUP, ROTATING SPINDLE
• Clot impedes rotation of the pin
• Additional tests available

Question 22

Sonoclot

Answer 22

• Viscoelastic detection system
• Provides information on the entire hemostatic process
• Generates a qualitative graph and quantitative results
- Tells you
-coagulation, formation of the fibrin network, clot retraction, and the breakdown of the clot
- helps determine if it’s a coagulation issue or if there is a bleeder
• Tubular probe oscillates up and down within a blood sample
• Senses resistance to motion that the probe encounters through various stages of hemostasis
- slightly faster than other 2
- fibrinolysis takes longer to be determined

Question 23

Sonoclot graph

Answer 23

• Clot evolution saved as a graph

* Clot signal value versus time

Question 24

Sonoclot Liquid Phase

Answer 24

• Ends when the viscosity of the sample begins to increase with thrombin generation and the resulting initial fibrin formation

Question 25

Sonoclot fibrin gel formation

Answer 25

* Once thrombin forms, the fibrinogen converts to fibrin | * Fibrin spontaneously polymerizes into a fibrin gel

Question 26

Sonoclot clot retraction

Answer 26

* Occurs when platelets function normally * Platelets adhere to nodes of the fibrin gel and cause the gel to collapse together or retract * As the clot retracts, it tightens

Question 27

Sonoclot time to peak

Answer 27

* The faster the time to peak, the greater the platelet function * Sharp, well defined peaks infication strong retraction * Dull, poorly defined peaks indicate weak retraction