Off-label substitution therapy with a fibrinogen concentrate generally improved global laboratory coagulation results and as supplementary intervention, appeared to diminish the requirements for RBC, FFP, and platelet substitution in this patient cohort.

To cite this article: Fenger-Eriksen C, Jensen TM, Kristensen BS, Jensen KM, Tønnesen E, Ingerslev J, Sørensen B. Fibrinogen substitution improves whole blood clot firmness after dilution with hydroxyethyl starch in bleeding patients undergoing radical cystectomy: a randomized, placebocontrolled clinical trial. J Thromb Haemost 2009; 7: 795-802.Summary. Background: Infusion of artificial colloids such as hydroxyethyl starch (HES) induces coagulopathy to a greater extent than simple dilution. Several studies have suggested that the coagulopathy could be corrected by substitution with a fibrinogen concentrate. Objectives: The aims of the present prospective, randomized, placebo-controlled trial were to investigate the hemostatic effect of a fibrinogen concentrate after coagulopathy induced by hydroxyethyl starch in patients experiencing sudden excessive bleeding during elective cystectomy. Methods: Twenty patients were included. Blood loss was substituted 1:1 with HES 130/0.4. At a dilution level of 30%, patients were randomly selected for intra-operative administration of a fibrinogen concentrate or placebo. The primary endpoint was maximum clot firmness (MCF), as assessed by thromboelastometry. Secondary endpoints were blood loss and transfusion requirements, other thromboelastometry parameters, thrombin generation and platelet function. Results: Wholeblood MCF was significantly reduced after 30% dilution in vivo with HES. The placebo resulted in a further decline of the MCF, whereas randomized administration of fibrinogen significantly increased the MCF. Furthermore, only 2 out of 10 patients randomly chosen to receive fibrinogen substitution required postoperative red blood cell transfusions, compared with 8 out of 10 in the placebo group (P = 0.023). Platelet function and thrombin generation were reduced after 30% hemodilution in vivo, and fibrinogen administration caused no significant changes. Conclusions: During cystectomy, fluid resuscitation with HES 130/0.4 during sudden excessive bleeding induces coagulopathy that shows reduced whole-blood maximum clot firmness. Randomized administration of fibrinogen concentrate significantly improved maximum clot firmness and reduced the requirement for postoperative transfusion.

Coagulopathy induced by haemodilution with either HES 200/0.5, HES 130/0.4, and dextran 70 may be improved by fibrinogen supplementation.

Acquired fibrinogen deficiency seems to be the leading determinant in dilutional coagulopathy, and ex vivo addition corrected the coagulopathy completely.

Pasteurized fibrinogen concentrate is derived from human plasma. Its half life is 2.7 days in patients with congenital fibrinogen deficiency. For congenital and acquired deficiency in vivo recovery rates vary from 60% to 109%. Reportedly, administration of pasteurized fibrinogen in patients with congenital deficiency is efficacious. Acquired deficiency of fibrinogen appears to be an early event in seriously bleeding patients, preceding critical levels of platelets or other coagulation factors. Experimental animal studies, as well as clinical observations suggest a beneficial role of early substitution with fibrinogen in management of critical traumatic and surgical bleeds. Pasteurized fibrinogen concentrate is well tolerated and associated with a low incidence of adverse thrombo-embolic events.

Background: Thromboelastography/metry (TEG; Haemoscope, Niles, IL/ROTEM; Tem International GmbH, Munich, Germany) is increasingly used to guide transfusion therapy. This study investigated the diagnostic performance and therapeutic consequence of using kaolin-activated whole blood compared with a panel of specific TEM-reagents to distinguish: dilutional coagulopathy, thrombocytopenia, hyperfibrinolysis, and heparinization. Methods: Blood was drawn from 11 healthy volunteers. Dilutional coagulopathy was generated by 50% dilution with hydroxyethyl starch 130/0.4 whereas thrombocytopenia (mean platelet count 20 ϫ10 9 /l) was induced using a validated model. Hyperfibrinolysis and heparin contamination were generated by tissue plasminogen activator 2 nM and unfractionated heparin 0.1U/ml, respectively. Coagulation tests were run on ROTEM delta. Results: Kaolin-activated whole blood showed no differences between dilutional coagulopathy and thrombocytopenia (mean clotting time 450 s vs. 516 s, ␣-angle 47.1°vs. 41.5°, maximum clot firmness 35.0 mm vs. 34.2 mm, all P values Ն0.14). Hyperfibrinolysis specifically disclosed an increased maximum lysis (median: 100%, all P values less than 0.001), and heparin induced a distinctly prolonged clotting time (2283 s, all P values less than 0.02). The coagulopathies were readily distinguishable using a panel of TEMreagents. In particular, dilutional coagulopathy was separated from thrombocytopenia using FIBTEM (maximum clot firmness 1.9 mm vs. 11.2 mm, P Ͻ 0.001). The run time of analysis to achieve diagnostic data was shorter applying a panel of TEMreagents. A transfusion algorithm based on kaolin suggested platelets in case of dilutional coagulopathy, whereas an algorithm applying TEM-reagents suggested fibrinogen. Conclusion: Monoanalysis with kaolin was unable to distinguish coagulopathies caused by dilution from that of thrombocytopenia. Algorithms based on the use of kaolin may lead to unnecessary transfusion with platelets, whereas the application of TEM-reagents may result in goal-directed fibrinogen substitution.

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This study demonstrated that different automated coagulation analyzers revealed significantly different levels of fibrinogen. The presence of colloid plasma expander gave rise to erroneous high levels of fibrinogen returned from some coagulation analyzers employing the method of Clauss.