1.35 Thromboelastography

Question 1

Explain principle behind the function of a TEG machine

Answer 1

Bedside analysis clotting

Whole blood
Produces quick results on quality and speed of clot formation

Small sample whole blood
Introduced into rotating and oscillating cup in which a wire sits

As blood clot thickens
Movements of cup transmitted via wire
and translated into graphical output
correlates w/ viscoelastic properties of clot formed

Advantage of teg
provides info strength cloth formed
and fibrinolysis

Neither which assess using APTT or PT

Question 2

TEG parameters

R time

Answer 2

Time taken from start test to initial fibrin formation
1mm

Correlates with APTT and PT

Question 3

K TIme

Answer 3

Time taken for graph to widen to 20mm

Represents dynamic of clot formation

depends on fibrinogen formation
platelet function

Question 4

a angle

Answer 4

Angle measured between midline of tracing
and line drawn from 1mm point
tangential to curve

Represents acceleration of fibrin build up and cross linking

Question 5

Maximum amplitude MA

Answer 5

Represents ultimate strength of clot

Depends on number and function of platelets and time

Question 6

Lysis Ly30

Answer 6

Measure percentage amplitude reduction 30 min after MA

Indicates stability of clot

Question 7

abnormal teg traces

Anticoagulants

Answer 7

Increased R time + K time

Reduce MA and alpha angle

Anticoagulants
page 75
hourglass in half with longer line

Question 8

Antiplatelet agents thrombocytopaenia

Answer 8

Normal R time
Increased K time
reduced MA
page 75

long sausage

Question 9

DIC

stage 1

Answer 9

Hypercoagulable state and 2nd fibrinolysis

Reduced R Time and K Time

Increased a angle and MA
then continous drop

Ly30>7.5%
ly60>15%

Question 10

DIC stage 2

Answer 10

Reduced R Time and K Time

Increased a angle

Decreased MA