Fibrinogen Replacement Guidelines

Introduction to Fibrinogen Replacement

Fibrinogen serves as the precursor to fibrin, the primary structural component of blood clots, with normal plasma levels ranging from 2.0 to 4.5 g/L, and maintaining adequate fibrinogen levels is critical for achieving hemostasis in bleeding disorders 1, 2, 3
The minimal level of fibrinogen required for hemostasis is 100 mg/dL (1.0 g/L), as stated by the Association of Anaesthetists and supported by European guidelines on management of bleeding following major trauma 2, 3

Fibrinogen levels below 1 g/L (100 mg/dL) in the context of hemorrhage are usually insufficient for hemostasis, and an initial dose of fibrinogen that raises plasma levels above 1 g/L will provide sufficient hemostasis, according to the Association of Anaesthetists guidelines and European guidelines on management of bleeding following major trauma 2, 3
For patients with suspected congenital afibrinogenemia or acquired fibrinogen deficiency, administer fibrinogen concentrate or cryoprecipitate to achieve a minimum level of 100 mg/dL, with an initial dose of 3-4 g or 50 mg/kg of cryoprecipitate (approximately 15-20 units in a 70-kg adult, adjusted for the child's weight) 3, 4
A target level of 150-200 mg/dL may provide more optimal clot formation, especially in cases of active bleeding, and the American College of Cardiology recommends maintaining fibrinogen >100 mg/dL (1.0 g/L) during active bleeding, with higher targets of 1.5-2.0 g/L for severe hemorrhage 4, 1

Recent evidence suggests that maintaining fibrinogen above 150 mg/dL may be beneficial in cases of severe hemorrhage, and laboratory methods to measure fibrinogen concentration may have methodological issues, especially in the presence of artificial colloids 4
Laboratory monitoring should include plasma fibrinogen levels, viscoelastic testing (ROTEM/TEG), and PT/aPTT to evaluate overall coagulation status, and monitor fibrinogen levels frequently along with platelet count, PT, and APTT, and repeat fibrinogen level 15-30 minutes after administration 1, 5, 6
Failure to address other aspects of coagulation (platelets, other clotting factors) may limit the effectiveness of fibrinogen replacement, and concomitant treatments such as tranexamic acid and correction of hypocalcemia and hypomagnesaemia should be considered in certain situations 4, 2

Fibrinogen deficiency can be congenital (rare genetic disorders such as afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia) or acquired (more common, occurring in conditions like massive hemorrhage, liver disease, disseminated intravascular coagulation, major surgery, and obstetric complications) 2, 5
Low fibrinogen levels (<100 mg/dL) are associated with spontaneous and procedure-related bleeding, particularly in patients with cirrhosis, and a fibrinogen threshold from 100 to 200 mg/dL has been recommended for fibrinogen replacement in the setting of bleeding in cirrhosis, with 120 mg/dL being the most commonly used cut-off 1
In patients with cancer-associated DIC with active bleeding, maintain fibrinogen >150 mg/dL, and address underlying cause (especially important in malignancy-associated DIC) 7
For women with congenital fibrinogen disorders during pregnancy, a trough fibrinogen level of ≥1 g/L (100 mg/dL) should be maintained throughout pregnancy, and for labor, delivery, and neuraxial anesthesia, higher levels of ≥1.5 g/L (150 mg/dL) are recommended 8

Fibrinogen concentrate has advantages including rapid and predictable increase in fibrinogen levels, standardized fibrinogen content, lower volume, no need for cross-matching, and viral inactivation/elimination steps, and is recommended as the first-line treatment for patients with fibrinogen deficiency by the American Society of Anesthesiologists and the International Society on Thrombosis and Haemostasis 2, 1, 5, 7
Cryoprecipitate can be used when fibrinogen concentrate is unavailable, typically two pools for persistent fibrinogen <150 mg/dL, but has disadvantages including requiring thawing, larger volume, and potential for transfusion reactions 7
Fresh Frozen Plasma (FFP) is less effective than fibrinogen concentrate for correcting hypofibrinogenemia, requires higher volumes (15-30 ml/kg), and consider prothrombin complex concentrates if volume overload is a concern 7