INTRODUCTION: Recent availability of lyophilized fresh frozen plasma(Lyo-FFP) and lyophilized platelet(Lyo-PLT) on thromboelastography(TEG) may help to target therapy with the required blood product and thereby correct coagulopathy. This study was performed to assess the in vitro effect of LyoFFP and Lyo-PLT on human blood diluted with normal saline by TEG. METHODS: Venous blood from 8 healthy volunteers was diluted to 50volume%(D1) and 75volume%(D2) with 37degreesC normal saline for native TEG. Then, D1 and D2 were mixed with 0.5 ml citrate for citrate TEG(CD1 and CD2). The TEGs of CD1 and CD2 treated with Lyo-FFP and Lyo-PLT were compared with TEGs of D1, D2, CD1 and CD2 . All of blood samples were checked for hematocrit, platelet count and fibrinogen concentration. All the TEGs were compared for significance of differences by repeated measure ANOVA. RESULTS: D1 and D2 showed much lower hematocrit, platelet count and fibrinogen than control. In serial hemodilution there were significant changes in only maximal amplitude(MA) in D1 and all TEG parameters in D2 were depressed. Addition of Lyo-FFP and Lyo-PLT to D1 did not show any positive change in TEG parameters. However, addition of Lyo-FFP and Lyo-PLT to D2 showed significant improvements in reaction time and alpha angle, but not in MA. CONCLUSIONS: Lyo-FFP may be helpful in determining therapy for bleeding associated with coagulation factor deficiencies. However, the role of Lyo-PLT for the detection of platelet deficiency needs further evaluation.
Blood Coagulation Factors ; Blood Platelets* ; Citric Acid ; Fibrinogen ; Healthy Volunteers ; Hematocrit ; Hemodilution ; Hemorrhage ; Humans* ; Plasma* ; Platelet Count ; Reaction Time ; Thrombelastography

BACKGROUND: Prophylactic administration of tranexamic acid (TA) reduces bleeding and transfusion requirement after open heart operations. This study was performed to determine the relationship between inhibition of fibrinolysis and TA blood concentration. METHOD: In phase I, recombinant tissue plasminogen activator[r-tPA (0, 50, 100, 150 ng/ml)] was added to the blood of volunteer and induced fibrinolysis. In phase II, 4 thromboelastography (TEG) models of severe fibrinolysis in which TA was added to achieve blood levels (0, 0.72, 1.44, 2.88 mg/ml) were compared to determine the lowest effective dose. In phase III, the lowest dose (0.72 mg/ml) was mixed with the blood and evaluated on TEG in open heart operation. In phase IV, a placebo group and study group receiving TA in an loading dose of 5 mg/kg before bypass following infusion of 2 mg/kg/hour. Used analysis is Mann Whitney U test and Wilcoxon rank signed test. RESULT: In phase I, fibrinolytic inhibition at A30/MA (r=0.752) and A60/MA (r=0.735) were linearly correlated with the blood r-tPA concentration. In phase II, severe fibrinolysis (r-tPA 100 ng/ml) was reversed completely at all doses of TA. In phase III, the fibrinolysis index at 10 min. after starting bypass, aorta declamping, and 1 hour after operation were improved when the patient's blood was treated with TA (0.72 mg/ml). In phase IV, blood treated with TA showed less fibrinolysis and better TEG results than the placebo group. CONCLUSION: A small dose of TA (5 mg/kg), which was determined by an in vitro model of fibrinolysis on TEG, was effective in preventing changes in fibrinolytic index during cardiopulmonary bypass in open heart surgery.
Aorta ; Cardiopulmonary Bypass ; Fibrinolysis* ; Heart* ; Hemorrhage ; Plasminogen ; Thoracic Surgery* ; Thrombelastography* ; Tranexamic Acid* ; Volunteers