Coagulation- A Surgical Perspective Flashcards
3 stages of hemostasis
vascular, platelet, and coagulation phase
__________ may be recommended for those who bruise easily, have excessive bleeding,or take medications after a stroke or heart attack that can alter platelet function; to detect resistance to aspirin or clopidogrel; and before certain surgeries
Platelet function tests
_____ = (patient PT/ mean normal PT) ^ ISI
International Normalized Ratio (INR)
Common causes of prolonged PT
Warfarin use, Vitamin K deficiency, liver disease
Tests the rate of conversion of Factor VII to VIIa; measures effectiveness of the extrinsic and common pathway (normal 12-13 secs)
Prothrombin time
stage of hemostasis where Formation of a loose and temporary platelet aggregate at the site of injury. Platelets bind to collagen. After the activation, platelets change their shape and in the presence of fibrinogen, aggregate to form the hemostatic Primary platelet plug
platelet phase
about 15% of the hemophilia population, tend to have bleeding episodes after injuries. •They may also experience occasional bleeding episodes without obvious cause. These are called “spontaneous bleeding episodes
moderate hemophilia
about 60% of the hemophilia population, have bleeding following an injury and may have frequent spontaneous bleeding episodes, often into the joints and muscles
severe hemophilia
stage of hemostasis where conversion of fibrinogen to fibrin happens, fibrin binds the platelets to form a clot, and formation of a fibrin mesh that tightly binds to the platelet aggregate which gives rise to a more stable hemostatic plug (clot)
coagulation phase
Shortage of von Willebrand factor: most common form
Type 1 VWD
50,000-100,000 platelets
Mild Thrombocytopenia
flawed von Willebrand factor (usually mild): less common
Type 2 VWD
International sensitivity index determined for each batch of thromboplastin reagents by manufactures
ISI
_______ and _______ constitute over 90 % of all congenital bleeding disorders
Hemophilias A and B, Von Willebrand’s Disease
Teeth can be extracted with patients with Hemophilia A and B under the cover of _______ or _______ that inhibit fibrinolysis
epsilon (aminocaproic acid) or tranexamic acid