Summary
In trauma patients, resuscitation treatment of intravascular volume may cause haemodilution
including blood cell- and plasma-dilution. After plasma-dilution, fibrinogen is the
first factor that decreases to critically low concentrations. Fibrin formed in lowered
levels is susceptible to fibrinolysis, a natural forerunner for bleeding. To assess
whether a fibrinogen concentrate or a factor XIII (FXIII) concentrate can reverse
the impairment of fibrin properties after plasma dilution, different laboratory methods
were used to determine thrombin generation and fibrin quantity/quality in a normal
plasma sample diluted in vitro. Coagulation and clot lysis by plasmin were triggered with tissue factor and rt-PA,
respectively. We found that while the endogenous thrombin potential (ETP) was unaffected
after plasma-dilution due to postponement of thrombin decay, levels of fibrinogen
and hence fibrin were decreased in dilution degree-dependency. The imbalance between
influence of the dilution on thrombin activity and fibrin formation brought unexpected outcomes of fibrin properties: the formed clots favoured the degradation by plasmin
but the fibrin networks remained tighter/less permeable. This proteolytic tendency
was partly overturned by the fibrinogen concentrate added (total fibrinogen ≥ 2 g/l),
and much more affected if used in combination with tranexamic acid (a fibrinolysis
inhibitor) at small doses. No reversal effect resulted from the FXIII concentrate
added. We conclude that plasma-dilution did reduce the proteolytic resistance of formed
clots. The fibrinogen concentrate, better together with small doses of tranexamic
acid, may reverse the impairment of fibrin property. The FXIII concentrate is not
effective in this regard in our in vitro model using platelet-poor plasma.
Keywords
Plama dilution - coagulopathy - fibrin proteolysis - fibrinogen concentrate - FXIII
concentrate - tranexamic acid