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Effects of protamine and heparin can be detected and easily differentiated by modified thrombelastography (Rotem®): an in vitro study  M Mittermayr, J.

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Presentation on theme: "Effects of protamine and heparin can be detected and easily differentiated by modified thrombelastography (Rotem®): an in vitro study  M Mittermayr, J."— Presentation transcript:

1 Effects of protamine and heparin can be detected and easily differentiated by modified thrombelastography (Rotem®): an in vitro study  M Mittermayr, J Margreiter, C Velik-Salchner, A Klingler, W Streif, D Fries, P Innerhofer  British Journal of Anaesthesia  Volume 95, Issue 3, Pages (September 2005) DOI: /bja/aei197 Copyright © 2005 British Journal of Anaesthesia Terms and Conditions

2 Fig 1 Variables of Rotem® analysis are coagulation time (CT, s), corresponding to the reaction time (r time) in conventional TEG®; clot formation time (CFT, s), corresponding to the coagulation time (k time); maximum clot firmness (MCF, mm), which is equivalent to the maximum amplitude; and the α angle, which measures the speed of clot formation. Maximum lysis (ML, %) is defined as the ratio of the lowest clot strength after reaching MCF, to MCF. CT measurement relies mainly on the concentration of coagulation factors and the presence of inhibitors, and reflects initial thrombin generation and the formation of first trace amounts of fibrin. CFT is defined as the time needed to reach a clot strength of 20 mm and also depends on the concentration of fibrinogen and the numbers and function of platelets. MCF reflects the interaction of fibrinogen/fibrin with platelets and coagulation factor FXIII. British Journal of Anaesthesia  , DOI: ( /bja/aei197) Copyright © 2005 British Journal of Anaesthesia Terms and Conditions

3 Fig 2 Measurement of coagulation time (CT) in undiluted (a) and 40% diluted (b) blood samples at various concentrations of heparin derived from the INTEM test (normal range, 100–240 s) and the HEPTEM test (left panel). CT-INTEM divided by CT-HEPTEM (right panel). Increasing concentrations of heparin significantly elevate CT-INTEM values in a dose-dependent manner, while CT-HEPTEM remains unchanged. Consequently, the CT-INTEM:CT-HEPTEM ratio increases to well above 1 with increasing heparin concentrations. Results from undiluted blood were comparable to those from diluted blood up to heparin concentrations of 0.4 U ml−1. Values are 10th percentile, 25th percentile, median, 75th percentile and 90th percentile. *P<0.05 compared with baseline; #P<0.05 between various concentrations of heparin. (c) Measurement of coagulation time (CT) at various concentrations of protamine derived from the INTEM test (normal range, 100–240 s) and the HEPTEM test (left panel). CT-INTEM divided by CT-HEPTEM (right panel). Increasing concentrations of protamine significantly elevate CT-INTEM values in a dose dependent manner, while CT-HEPTEM increases in parallel. Consequently, the CT-INTEM:CT-HEPTEM ratio remains at 1 with increasing protamine concentration. Values are 10th percentile, 25th percentile, median, 75th percentile and 90th percentile. *P<0.05 compared with baseline; #P<0.05 between various concentrations of protamine. (d) Measurement of coagulation time (CT) at control (H0/P0), at a fixed dose of heparin 0.4 U ml−1 (H0.4/P0) and after addition of protamine hydrochloride 0.2, 0.4, 0.8, 1.6 U ml−1 (H0.4/P0.2; H0.4/P0.4; H0.4/P0.8; H0.4/P1.6) (1 U protamine hydrochloride neutralizes 1 U heparin) using the INTEM and HEPTEM tests (left panel). CT-INTEM divided by CT-HEPTEM (right panel). Values are 10th percentile, 25th percentile, median, 75th percentile and 90th percentile. British Journal of Anaesthesia  , DOI: ( /bja/aei197) Copyright © 2005 British Journal of Anaesthesia Terms and Conditions


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