Flashcards in Hemostasis Deck (34)
What is the life span of a platelet?
How quickly does a platelet plug form?
What are platelets attracted to in vascular endothelium when it is disrupted?
What are the three reactions that platelets undergo when they come in contact with collagen?
Adhesion and shape change, aggregation, secretion
Exposure of subendothelium and platelet adhesion depends on what factor?
von Willebrand factor
When platelets are activated, what do they do?
Attach to each other and release chemotactic factors
What is the coagulation cascade?
Series of reactions leading to fibrin clot formation
Cross-linking fibrin, trapping RBCs, plasma, and PLTs w/in platelet plug
Coagulation cascade (fibrin clot)
What becomes absorbed to fibrin fibers as they develop?
What does anti-thrombin in the blood stream do?
Inactivates thrombin and prevents excessive clotting
What can bind to anti-thrombin and make it more potent to prevent coagulation?
How will mucous membranes of a hemodynamically compromised patient appear?
Petechiation, echymosis, bleeding
What are the key tests in assessment of primary hemostasis?
PLT count and bleeding time
At what PLT level do dogs and cats have spontaneous bleeding?
What is normal buccal mucosal bleeding time?
What are the two most common tests used to evaluate the intrinsic pathway?
Activated clotting time (ACT) and activated partial thromboplastin time (aPTT)
What is normal ACT?
Measures time required for fibrin clot formation in fresh whole blood
Activated clotting time
What pathways does ACT and aPTT test?
Intrinsic and common pathways
What test can you to to evaluate the extrinsic pathway?
Prothrombin time (PT)
Which pathway is Factor 7 part of?
Why is factor 7 most reliable for measuring hemostasis?
What are Vit K dependent coag factors?
2, 7, 9, 10
What is platelet dysfunction most commonly due to?
Low concentration of vW factor
Which dog breed is most predisposed to platelet dysfunction d/t low vWf?
What is the inheritability of vWf deficiency?
How do you treat PLT dysfunction d/t vWf deficiency?
What are x-linked factor deficiencies?
Hemophilia A and B
What factor is deficient with Hemophilia A?