202207262305
Status:
Tags: haematology
Fibrinogen
Obstetrics:
| Product | Amount of fibrinogen |
|---|---|
| 1u whole blood (450ml) | 800-1500mg |
| 1u FFP (250ml) | 500mg |
| 1u cryoprecipitate (20ml) | 250mg |
| Fibrinogen conc. | 1 gram vial |
Fibrinogen (Factor I) is converted to Fibrin (Factor Ia) by thrombin (Factor IIa)
Insoluble Fibrin polymerizes to form a three-dimensional matrix stabilized by Factor XIIIa which supports
- platelet aggregation,
- mature clot formation,
- clot stability,
- retraction
In healthy individuals, normal plasma fibrinogen levels range from 1.5 to 3.5 g/L
fibrinogen also serves as an acute phase reactant and may be elevated in many physiologic states. ↑ fibrinogen are a/w
- infection,
- inflammation,
- cardiovascular disease
- recent trauma,
- pregnancy
In the 3rd trimester of pregnancy, normal fibrinogen levels are typically closer to 5 g/L
Fibrinogen is one of the first coagulation factors to be depleted with large volume hemorrhage, and existing clinical studies suggest targeting a plasma fibrinogen concentration of at least 1.5–2 g/L in both cardiac surgical patients and trauma patients, as plasma fibrinogen concentrations below this threshold are associated with excess bleeding and adverse clinical outcomes
In the obstetric population, fibrinogen levels less than 2 g/L are associated with worse outcomes, although practice guidelines may still offer a target fibrinogen ranging from 1.5 to 2 g/L
Several authors advocate for treatment thresholds >3 g/L in this population, but existing evidence suggests that fibrinogen replacement is unlikely to improve outcomes when the serum fibrinogen is concentration >2 g/L
| Patient Population | Conventional Coagulation Testing | VHA | Notes |
|---|---|---|---|
| Trauma | Fibrinogen Concentration >1.5–2 g/L | - FIBTEM A5 < 10 mm - FIBTEM A10 < 7 mm - FIBTEM MCF <10 mm - EXTEM A5 < 35 mm and FIBTEM A5 < 9 mm - TEG Functional Fibrinogen MA < 20 mm |
Evidence base generally supporting both the use of conventional tests of coagulation and viscoelastic testing |
| Cardiac Surgery | Fibrinogen Concentration >1.5–2 g/L | - FIBTEM A10 < 10 mm and EXTEM A10 < 40 mm - FIBTEM A10 ≤ 8 mm - TEG MA < 40 mm and Functional Fibrinogen <8 mm |
Evidence base generally supporting both the use of conventional tests of coagulation and viscoelastic testing. Recent guidelines support the use of point-of-care hemostatic testing over conventional tests of coagulation |
| Liver Transplant | Fibrinogen Concentration >1.2–2 g/L | - EXTEM A5 < 25 mm and FIBTEM A5 < 8 mm - EXTEM MCF<35 mm and FIBTEM MCF <8 mm |
No clear consensus on validated algorithm to guide transfusion management. The weight of the evidence suggests that in conjunction with conventional coagulation tests, viscoelastic testing should be used for liver transplantation where available and feasible |
| Obstetrical | Fibrinogen Concentration >1.5–2 g/L (some authors advocate for >3 g/L) | - FIBTEM A5 < 10 mm - FIBTEM A5 < 5 mm or FIBTEM A10 < 6 mm, targeting A10 of 8 mm for controlled hemorrhage and 10 mm for ongoing hemorrhage - FIBTEM A5 < 12 mm - FIBTEM A5 < 7 mm or < 12 mm in active bleeding and EXTEM A5 < 47 mm |
Limited randomized trials and evidence base to guide management |
Fibrinogen concentrate is a pooled plasma-derived product prepared as a sterile, pathogen-reduced, concentrate powder.
It contains a standardized fibrinogen content of 20 mg/mL when reconstituted
The dose of fibrinogen concentrate can be calculated based on
- target plasma fibrinogen level,
- measured plasma fibrinogen level,
- body weight
Dose (mg/kg body weight) = (Target Level (mg/dL) – Measured Level (mg/dL))/(1.8 (mg/dL per mg/kg body weight))
A typical adult dose is 4g (approx. 70 mg/kg) and would typically raise the plasma fibrinogen by 1 g/L
vs cryoprecipitate
| Attributes | Cryoprecipitate | Fibrinogen Concentrate |
|---|---|---|
| Origin | Human Plasma | Human Plasma |
| Storage | Frozen (≤18 °C) | Room Temperature, Lyophilized |
| Shelf life | 1 year | 3 years |
| Volume | 300 mL | 200 mL |
| Near-Patient Storage Possible | No | Yes |
| Rapid preparation/injection | No, requires approximately 30 min for thawing | Yes, rapidly reconstituted |
| Pathogen reduction | Typically No (Pathogen Reduced Cryoprecipitate is now available in some jurisdictions) | Yes |
| Fibrinogen Content | Higher variability due to intrinsic differences in donor pool | Lower variability due to product standardization |
| The European Society of Anesthesiology and Intensive (ESAIC) Guidelines on Management of Severe Perioperative Bleeding recommend treatment with either fibrinogen concentrate or cryoprecipitate | ||
| The European Guideline on Management of Major Bleeding and Coagulopathy Following Trauma (5th Ed) endorses the use of fibrinogen concentrate |