Hemostasis

Question 1

What is the life span of a platelet?

Answer 1

5-10d

Question 2

How quickly does a platelet plug form?

Answer 2

Within 5min

Question 3

What are platelets attracted to in vascular endothelium when it is disrupted?

Answer 3

Collagen

Question 4

What are the three reactions that platelets undergo when they come in contact with collagen?

Answer 4

Adhesion and shape change, aggregation, secretion

Question 5

Exposure of subendothelium and platelet adhesion depends on what factor?

Answer 5

von Willebrand factor

Question 6

When platelets are activated, what do they do?

Answer 6

Attach to each other and release chemotactic factors

Question 7

What is the coagulation cascade?

Answer 7

Series of reactions leading to fibrin clot formation

Question 8

Cross-linking fibrin, trapping RBCs, plasma, and PLTs w/in platelet plug

Answer 8

Coagulation cascade (fibrin clot)

Question 9

What becomes absorbed to fibrin fibers as they develop?

Answer 9

Thrombin

Question 10

What does anti-thrombin in the blood stream do?

Answer 10

Inactivates thrombin and prevents excessive clotting

Question 11

What can bind to anti-thrombin and make it more potent to prevent coagulation?

Answer 11

Heparin

Question 12

How will mucous membranes of a hemodynamically compromised patient appear?

Answer 12

Petechiation, echymosis, bleeding

Question 13

What are the key tests in assessment of primary hemostasis?

Answer 13

PLT count and bleeding time

Question 14

At what PLT level do dogs and cats have spontaneous bleeding?

Answer 14

<30k/uL

Question 15

What is normal buccal mucosal bleeding time?

Answer 15

<4min

Question 16

What are the two most common tests used to evaluate the intrinsic pathway?

Answer 16

Activated clotting time (ACT) and activated partial thromboplastin time (aPTT)

Question 17

What is normal ACT?

Answer 17

60-90sec

Question 18

Measures time required for fibrin clot formation in fresh whole blood

Answer 18

Activated clotting time

Question 19

What pathways does ACT and aPTT test?

Answer 19

Intrinsic and common pathways

Question 20

What test can you to to evaluate the extrinsic pathway?

Answer 20

Prothrombin time (PT)

Question 21

Which pathway is Factor 7 part of?

Answer 21

Extrinsic pathway

Question 22

Why is factor 7 most reliable for measuring hemostasis?

Answer 22

Shortest half-life

Question 23

What are Vit K dependent coag factors?

Answer 23

2, 7, 9, 10

Question 24

What is platelet dysfunction most commonly due to?

Answer 24

Low concentration of vW factor

Question 25

Which dog breed is most predisposed to platelet dysfunction d/t low vWf?

Answer 25

Doberman pinscher

Question 26

What is the inheritability of vWf deficiency?

Answer 26

Autosomal dominant

Question 27

How do you treat PLT dysfunction d/t vWf deficiency?

Answer 27

DDAVP

Question 28

What are x-linked factor deficiencies?

Answer 28

Hemophilia A and B

Question 29

What factor is deficient with Hemophilia A?

Answer 29

Factor 8

Question 30

What factor is deficient with Hemophilia B?

Answer 30

Factor 9

Question 31

What coag tests are elevated with Vit K deficiency (rodenticide tox)?

Answer 31

PT and PTT

Question 32

How do you treat Vit K deficiency?

Answer 32

Vit K1 for 4wk

Question 33

What factors are part of the common pathways?

Answer 33

2 x 5 x 1 = 10

Question 34

What factors are part of the intrinsic pathway?

Answer 34

12, 11, 9, 8