Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics PhD (physio) Mahatma Gandhi medical college and research institute, puducherry – India

What is it and when started Thromboelastography is a point-of-care global hemostasis system used by anaesthetists largely to monitor perioperative changes in coagulation in surgical patients It was first developed by the German Dr. Hellmut Hartert at University of Heidelberg School of Medicine. in 1948

Thrombo elastography machine

Indications Cardiac Surgery Patient factors(aspirin,clopidogrel,heparin, clotting disorders) Vascular Surgery. Major obs. Haemorrhage Regional on heparin liver transplantation

What does it test ?? The visco elastic changes that occur during the hemostatic process TEG provides a real-time functional evaluation of the coagulation cascade, Platelet function Clot formation clot strengthening and fibrin cross-linkage clot lysis

classical thromboelastography a small sample of blood is placed into a cuvette (cup) rotated gently to imitate sluggish venous flow and activate coagulation. When a sensor shaft is inserted into the sample a clot forms between the cup and the sensor. The speed and strength of clot formation is measured depends on the activity of the plasmatic coagulation system, platelet function, fibrinolysis and other factors

Principle

Values the R value - time until the first evidence of a clot is detected The K value - the end of R until the clot reaches 20mm and this represents the speed of clot formation The angle is the tangent of the curve made as the K is reached and offers similar information to K The MA is a reflection of clot strength. Clot lysis time

R value R: R time is the period of latency from the time that the blood was placed in the TEG analyzer until the initial fibrin formation. This represents the enzymatic portion of coagulation. (clotting factors ) 4 – 8 minutes R = 11 – 14 min – FFP 8 ml/kg R > 14 FFP 15 ml/Kg

Prolonged R Shortened R Hypercoagulable state and early DIC

K: K time is a measure of the speed to reach a certain level of clot strength. This represents clot kinetics. 1 – 4 minutes alpha : measures the rapidity of fibrin built up and cross-linking (clot strengthening). This represents fibrinogen level. 45 – 75 deg

R normal K prolonged Platelet defect

MA: MA or maximum amplitude, is a direct function of the maximum dynamic properties of the fibrin and platelet bonding via GPIIb/IIIa and represents the ultimate strength of the fibrin clot. 55 – 70 mm 80 % platelets 20 % fibrinogen

Decrease and continuous decrease Platelet deficiency Primary fibrinolysis

LY30: LY30 measures the rate of amplitude reduction 30 min after MA. This represents clot lysis. Normal = 7.5 %

Primary fibrinolysis > 7.5 %

TO SUMMARIZE Cuvette pin 0.3 ml blood Visco elastic properties Full coagulation profile R, K,MA, LY 30 Disease s

TEG with heparinase heparinase (an enzyme breaking heparin) “heparinized” patients, prior to heparin reversal with protamine. This test may prove particularly useful during long pump runs, deep hypothermia, use of ventricular assist devices or complicated major vascular cases The test will also detect if more protamine is needed to fully reverse heparin.

To remove platelet effect Add recently FDA approved monoclonal antibody which binds to the platelet GPIIb/IIIa receptors, to the TEG sample eliminate platelet function from the thromboelastogram The MA will become a function of fibrinogen activity

Various diseases – TEG

The Sonoclot provides an alternative visco elastic measure of coagulation. In contrast to the TEG, Sonoclot immerses a rapidly vibrating probe into a 0.4-mL sample of blood. As clot formation occurs, impedance to probe movement through the blood increases and generates an electrical signal and characteristic clot “signature.” The Sonoclot may be used to derive the ACT, as well as to provide information regarding clot strength and fibrinolysis.

Treat the patient than TEG Thank you all