Intraoperative changes in blood coagulation and thrombelastographic monitoring in liver transplantation

Abstract

The blood coagulation system of 66 consecutive patients undergoing consecutive liver transplantations was monitored by thrombelastograph and analytic coagulation profile. A poor preoperative coagulation state, decrease in levels of coagulation factors, progressive fibrinolysis, and whole blood clot lysis were observed during the preanhepatic and anhepatic stages of surgery. A further general decrease in coagulation factors and platelets, activation of fibrinolysis, and abrupt decrease in levels of factors V and VIII occurred before and with reperfusion of the homograft. Recovery of blood coagulability began 30-60 min after reperfusion of the graft liver, and coagulability had returned toward baseline values 2 hr after reperfusion. A positive correlation was shown between the variables of thrombelastography and those of the coagulation profile. Thrombelastography was shown to be a reliable and rapid monitoring system. Its use was associated with a 33% reduction of blood and fluid infusion volume, whereas blood coagulability was maintained without an increase in the number of blood product donors.

Figure 1

A rapid infusion system, developed by JJ Sassano, MD, of the University of Pittsburgh School of Medicine.

Figure 2

Thrombelastography: sensitive bedside monitoring of coagulation. It measures the shear elasticity of a blood clot from the time when the first fibrin strands are formed to the completion of the clot formation, including fibrinolysis.

Figure 3

Variables and normal values measured by thrombelastography. Abbreviations: R—reaction time, 6–8 min; R + k—coagulation time, 10–12 min; α —clot formation rate, > 50°; MA—maximum amplitude, 50–70 mm; A₆₀—amplitude 60 min after MA; A₆₀/MA·100—whole blood clot lysis index, > 85%; and F—whole blood clot lysis time, > 300 min.

Figure 4

Thrombelastographic pattern of one patient. Reaction time, maximum amplitude, and clot formation rate improved after sequential transfusion of FFP, platelets, and cryoprecipitate. Rapid whole blood clot lysis was demonstrated during the second stage and the early part of the third stage of surgery. Transfusion of platelets and cryoprecipitate normalized the TEG pattern at the end of the operation. This patient was transfused 46 units of RBC, 48 units of FFP, 20 units of platelets, and 12 units of cryoprecipitate.