| Popis: |
Background: The efficacy of concentrates of fibrinogen and factor XIII in hypothermia and haemodilution has not yet been completely investigated. Clauss methods have not previously been evaluated perioperatively. Methods: Coagulation was assessed with rotational thromboelastometry (ROTEM) or free oscillation rheometry (FOR) in vitro and different fibrinogen measurement methods in observational studies. Results: Haemodilution with human albumin (HA) impaired clot strength (EXTEM MCF, maximal clot formation) less than the synthetic colloids hydroxyethyl starch (HES) or dextran (p0.001). Finally, when comparing seven different Clauss methods during cardiac surgery, within-method variability was low, but between-method variability was high (mean difference >0.5 g/l).No differences between pre- and post-weaning from cardiopulmonary by-pass was seen. Conclusion: Fibrinogen concentrate improved coagulation better after haemodilution with HA than synthetic colloids, but equal with or less than after crystalloid haemodilution. FXIII had an additional effect to that of fibrinogen. Hypothermia and haemodilution with HES interacted to impair coagulation. Fibrinogen+/-FXIII improved coagulation also at 33°C. Clauss methods after in vivo HES haemodilution did not overestimate fibrinogen; however, fibrinogen-dependent clot strength decreased more than fibrinogen concentration. Clauss methods varied considerably between methods. These findings support the use of fibrinogen concentrate after resuscitation with HA, also at hypothermia, but question the use of colloids, especially HES, in resuscitation. Clauss fibrinogen methods need to improve. |
