Flashcards in Hemostasis Deck (104)
Massive transfusion is defined as ___________.
one complete blood volume transfused within 24 hours
What is the role of antithrombin?
it binds thrombin (factor IIa) and factor Xa GREATLY
it binds IX, XI, and XII to a LESSER extent
removes them from circulation--> anticoagulating the blood
How does heparin work?
increases the effectiveness of antithrombin 1,000 fold or more
Where is antithrombin made?
Heparin binds to _______.
Heparin increases the rate of thrombin-antithrombin reaction by _______.
1000 fold or more
Name 2 disease processes that can cause an acquired antithrombin deficiency state.
1) cirrhosis of liver
2) nephrotic syndrome
What is the MOST common reason a patient can be unresponsive to heparin?
b\c they have an antithrombin deficiency
What is the appropriate ACT result indicating that a patient has been adequately heparinized before a CABG?
if the ACT is low you can give FFP because FFP contains all coagulation and anticoagulation factors made by the liver--> including antithrombin
What pathway or pathways does heparin block?
classical intrinsic and final common pathway
What is the reversal for heparin?
How does protamine work to reverse heparin?
it is a positively charged substance that combines electrostatically with heparin, a negatively charged substance--> this is a neutralization reaction
Protamine reverses the action of heparin by ______.
Warfarin (coumadin) binds to ______ receptors in the ______.
vitamin K receptors in the liver---> production of vit K dep factors (II, VII, IX, X) is depressed
What pathway is blocked with warfarin?
classical extrinsic and final common pathways
Recombinant hirudin, ximelagatran, and argatroban are direct _____ inhibitors.
What two tests assess heparin?
PTT and ACT
Heparinization is adequate if the ACT is > _______ sec.
What is the normal value? bleeding time
What is the normal value? platelet
What is the normal value? prothrombin time (PT)
What is the normal value? activated partial thromboplastin time (PTT)
What is the normal value? activate coagulation time (ACT)
_______ is the body's clot buster.
How does plasminogen (inactivated form of plasmin) get converted into plasmin? (2)
tpa and upa
tissue type plasminogen activator
urokinase type plasminogen activator
When a clot is formed, what is there all along that will assist in the destruction of the clot at a later time?
plasminogen is incorporated into the clot as it is formed
Plasminogen, the inactive form of plasmin, is synthesized in the ________ and circulates in the blood.
Where is TPA made and what is its role?
its made in endothelial cells---> released when needed to convert plasminogen into plasmin
Aprotinin and Amicar (epsilon aminocaproic acid) work by _______.