Causes of Coagulopathic Perioperative Bleeding
Undiagnosed inherited coagulation disorders
Previously undiagnosed inherited bleeding disorders (such as hemophilia A, hemophilia B, von Willebrand disease and deficiencies of factors I [fibrinogen], II [prothrombin], VII, X, and XIII) can present as perioperative bleeding.
Replacement of fluid with crystalloid or colloid infusion solutions dilutes the concentration of coagulation factors. Massive fluid transfusion can cause severe perioperative bleeding. In major blood loss, fibrinogen levels reach a critical value earlier than other procoagulatory factors, or platelets.26
Acquired fibrinogen (factor I) deficiency
Acquired fibrinogen (factor I) deficiency (hypofibrinogenemia) causes most cases of fibrinogen-deficiency-related severe bleeding.27 Acquired deficiency of fibrinogen may emerge as a result of:
- Diseases that reduce production or increase consumption of fibrinogen, e.g. liver disease, disseminated intravascular coagulation (DIC) or some malignancies
- Conditions where the fibrinogen molecule becomes dysfunctional (e.g. liver disease)
- Profound loss of fibrinogen due to massive bleeding, blood dilution with volume expanders or massive transfusion.28
Acquired fibrinogen deficiency is believed to be an early event in seriously bleeding patients, occurring before other coagulation factor and platelet deficiencies are detectable.28
Fibrinolysis is the process that breaks down a fibrin clot. A disturbance in the balance of fibrinolytic activators and inhibitors can result in excessive breakdown of fibrin clots, increasing the risk of excessive bleeding.29 Hyperfibrinolysis can occur due to thrombolytic therapy, liver failure, certain malignancies or secondary to DIC.30
Reduction in thrombin generation
In severe hemodilution, such as dilutional coagulopathy, the initiation of thrombin generation is reduced as a result of the consumption of platelets and coagulation factors, particularly fibrinogen, factor VII and factor XIII. This makes fibrin clots susceptible to fibrinolysis and causes profuse bleeding.31
If you would like to learn more about perioperative bleeding and recent advances to treatment, please visit perioperativebleeding.org.
9/10/2014 9:59 AM