hemostas

Hemostas is not a standard term in medical terminology and may represent a misspelling or regional variant of hemostasis. If used, it typically refers to the physiological process that stops bleeding after vascular injury.

Hemostasis consists of three overlapping phases: primary hemostasis, secondary hemostasis, and fibrinolysis. Primary hemostasis involves vasoconstriction and rapid formation of a platelet plug at the injury site. Platelets adhere to exposed collagen via von Willebrand factor, become activated, and recruit additional platelets through GPIIb/IIIa receptor–mediated aggregation. Secondary hemostasis activates coagulation factors in the blood, culminating in thrombin generation and conversion of fibrinogen to fibrin, stabilizing the plug into a cross‑linked clot. Tertiary hemostasis involves fibrinolysis, with plasmin dissolving the clot once the vessel is repaired.

Regulation is achieved by anticoagulant pathways (antithrombin, protein C and S) and fibrinolytic systems; imbalance can cause bleeding or thrombosis. Clinically, disorders of hemostasis include bleeding conditions such as hemophilia A and B and von Willebrand disease, as well as thrombotic conditions such as deep vein thrombosis and pulmonary embolism. Laboratory assessment typically includes platelet count and coagulation tests such as PT/INR and aPTT, with viscoelastic tests used in some surgical settings.

In practice, management aims to restore normal hemostasis, using approaches such as antifibrinolytics, vitamin K for deficiencies, transfusion of blood products, and, when appropriate, anticoagulant or procoagulant therapies. Because the term "hemostas" is not widely used in standard terminology, readers should verify its usage in context or refer to conventional discussions of hemostasis.