Fibrinogen Concentrate in Acute Hemorrhage: Mechanistic Insight, Thresholds, and Targeted Replacement.

Fibrinogen is an essential component of hemostasis and clot formation that stabilizes the platelet-dependent primary hemostatic process. Low fibrinogen levels can be primary (congenital) or secondary (acquired). Acquired hypofibrinogenemia may result from chronic diseases (e.g., liver, autoimmune diseases, and malignancies) or major hemorrhage (e.g., trauma, surgery). Low fibrinogen levels are both a symptom and a precipitating factor for coagulopathy and ongoing bleeding. Fibrinogen repletion with fibrinogen-containing products is important for managing coagulopathic bleeding with suspected or documented hypofibrinogenemia. Different available fibrinogen sources include fibrinogen concentrate, cryoprecipitate, and frozen plasma and vary based on multiple factors including fibrinogen content, purity, other clotting or non-clotting proteins (e.g., immunomodulating proteins or proteins of unknown function), preparation time, safety, volumes, and availability. Fibrinogen replacement strategies have been studied in trauma but also in patients undergoing spine, cytoreductive, and cardiac surgery. In this review, we discuss the physiological actions of fibrinogen, strategies for control of coagulopathic bleeding related to hypofibrinogenemia, and the therapeutic, logistical, and economic factors that influence treatment decisions. In addition, current guidelines and clinical studies were considered regarding the formation of evidence-based treatment strategies that can be individualized at the patient's bedside.