Hemostasis and Coagulation

Question 1

Why is hemostasis necessary?

Answer 1

Hemostasis is necessary to prevent or control blood loss due to blood vessel injury.

Question 2

How could platelets be described?

Answer 2

150,000 – 450,000/ µL (microliter)

Formed mostly in bone marrow with some platelets produced in the spleen

70% in circulation

30% stored in spleen

Lifespan 10 days

Question 3

What is the role of the spleen in hemostasis?

Answer 3

The spleen manufactures some platelets along with the bone marrow.

The spleen also stores platelets.

Question 4

What is the role of the liver in hemostasis?

Answer 4

Clotting Factors

I – XIII Designation of clotting factors

Most clotting factors are plasma proteins made in the liver

Some require Vitamin K for synthesis or function

Question 5

What is hypercoagulability? (Platelet function and clotting factors?)

Answer 5

Platelet function

Thrombocytosis – excess platelets

Excessive clotting

-Inherited
-Acquired

Question 6

What is bleeding?
(Platelet function and clotting factors?)

Answer 6

Platelet function

-Thrombocytopenia – inadequate platelets
-Impaired platelet function

Deficient clotting factors

-Inherited
-Acquired

Question 7

What is the etiology of hypercoagulability with increased platelet functions?

Answer 7

Abnormal blood flow through the vessel (s)
- “Blood is more viscous.”

Damage to the endothelial layer.

Platelets are hypersensitive to substances that promote adhesiveness and aggregation.

Question 8

How is excessive clotting described? (inherited)

Answer 8

Factor V gene mutation

Venous thrombosis

Thromboembolism – pregnancy

Abruptio placentae

Prothrombin gene mutation

Question 9

How is excessive clotting described? (acquired)

Answer 9

(Venous stasis)

Immobility

Myocardial infarction

Cancer

Smoking

Obesity

Increased estrogen - Oral contraceptives

Question 10

What is Thrombocytopenia?

Answer 10

Decreased platelet count

Question 11

What are some examples of Thrombocytopenia?

Answer 11

Heparin-induced thrombocytopenia

Immune-induced thrombocytopenia

Thrombotic thrombocytopenic purpura

Question 12

What is Thrombocytopathia?

Answer 12

Impaired platelet function

Question 13

What are some examples of Thrombocytopathia?

Answer 13

Von Willebrand’s disease

Drugs

End-stage renal failure

Cardiopulmonary bypass

Question 14

What causes decreased platelet production?

Answer 14

Aplastic anemia

Bone marrow cancer

Chemotherapy

Radiation

Question 15

What causes decreased platelet survival?

Answer 15

Disseminated intravascular coagulation

Infections

Mechanical heart valves

Cells are damaged moving through the metal parts of the artificial valve

Question 16

What is the etiology of Hemophilia A?

Answer 16

Sex-linked recessive chromosomal disorder

Affects mostly males

Deficiency Factor VIII or IX

Elevated APTT (activated partial thromboplastin time)

Question 17

How can you prevent Hemophilia? (primary)

Answer 17

Trauma prevention that may include protective gear

Question 18

How can you prevent Hemophilia? (tertiary)

Answer 18

(To decrease disability or death)

Factor VIII infusion

Clotting factor infusion obtained from whole blood

Fresh frozen plasma Cryoprecipitate

Question 19

What is Disseminated Intravascular Coagulation (DIC)?

Answer 19

Sometimes called consumptive coagulopathy related to (r/t) the consumption of clotting factors.

Acquired as a complication of another serious condition.

Often occurs after a major hemorrhage and/or infection.

Excessive clotting in microvasculature (capillaries) with excessive bleeding due to depletion of clotting factors

The underlying cause is depletion of clotting factors.

Question 20

What conditions might lead to DIC?

Answer 20

Bleeding from pregnancy complications (About 50% of cases)

Major trauma

Hemorrhage

Severe infection

Snakebite

Question 21

What are examples of coagulated lab tests?

Answer 21

Complete Blood Count (CBC)

Bleeding time

Activated partial thromboplastin time (APTT)

Prothrombin Time (PT)

International Normalized Ratio(INR)

Platelet count

Question 22

What is Activated partial thromboplastin time?

Answer 22

Assesses function of the intrinsic coagulation pathway

33-45 seconds is normal range

Critical value > 90 seconds

Elevation of the value indicates bleeding is more prolonged than normal

Below normal value indicates clotting is more than normal

Measures effectiveness of the anticoagulant Heparin

For client receiving Heparin as IV infusion for anticoagulation treatment, desired APTT value is 1.5 – 2 times normal

Question 23

What is Prothrombin time/ International normalized ratio?

Answer 23

Assesses function of the extrinsic coagulation pathway

PT result varies r/t reagent used each time blood is tested

Normal results are in the range of 10 – 14 seconds and 100% coagulated

Elevation of the value indicates bleeding is more prolonged than normal

Below normal value indicates clotting is more than normal

Measures effectiveness of anticoagulant drug, sodium warfarin

Question 24

What is INR?

Answer 24

Thromboplastin reagents used to test the blood vary greatly between manufacturers and lots, so the World Health Organization developed a comparative mathematical ratio called the International Normalized Ratio - INR.

Normal range 0.8 – 1.1

> 3.6 Critical value, unless on warfarin for intentional anticoagulation

Question 25

What are some key clinical points of INR?

Answer 25

Above normal value indicates bleeding is more prolonged than normal

Below normal value indicates clotting is more than normal

Question 26

Why might the spleen be removed when platelet count is low?

Answer 26

To fix Thrombopenia

(These patients will be at risk for infection.)

Question 27

Why does liver dysfunction alter coagulation?

Answer 27

Because clotting factors are manufactured by the liver

Question 28

Thrombocytosis is…

Answer 28

Excess platelets

Excessive clotting

Question 29

Thrombocytopenia is…

Answer 29

Inadequate platelets (impaired platelet function)

Deficient clotting factors