Coagulation Disorders

Question 1

Heparin Induced Thrombocytopenia

Answer 1

Caused by abnormal antibodies that activate platelets, causing clots to form and depleting platelet counts in blood
Consumes the platelets, to be rendered useless. Impaired ability to clot

Question 2

Antidote for heparin:

Answer 2

protamine sulfate

Question 3

warfarin side effects:

Answer 3

cholesterol microemboli

Question 4

Anticoagulants

Answer 4

Anticoagulant: prevent to body from completing the clotting cascade and developing a blood clot. Prevents clot formation; does not break down existing clots. NOT A THROMBOLYTIC

Question 5

Heparin and LMWH

Answer 5

• Heparin: enhances antithrombin III activity
  o Decreases thrombin activity
  o Decreases prothrombinase
• LMWH
  o Also enhances AT-III activity but more specific to prothrombinase (active factor X)
  o Fever adverse effects than heparin
  o Less risk of thrombocytopenia compared to heparin
• Used for acute thromboembolic disorder including DVT, PE, unstable angina, and evolving MI
• Prophylaxis for clotting
• Monitor PTT when on heparin.

Warfarin, apixaban, rivaroxiban are all anticoagulants

Question 6

Anti-platelets (ex. aspirin)

Answer 6

• antagonize the receptors that communicate with platelets, thereby preventing platelet aggregation, and preventing clot formation.
• inhibit platelet aggregation

Question 7

Receptors used in platelet aggregation

Answer 7

ADP receptors

glycoprotein IIb/IIIa receptors

Question 8

Thrombolytics

Answer 8

breakdown existing clots. Converts plasminogen to plasmin, which then degrades fibrin in clots.

Question 9

Anti-fibrinolytics

Answer 9

refers to drugs that prevent the breakdown of fibrin/existing clots, thereby preventing excessive bleeding. does this by displacing plasminogen from fibrin, inhibiting fibrinolysis.

Question 10

PT - prothrombin time

Answer 10

measures the time it takes plasma to clot when exposed to tissue factor, which assess the extrinsic and common pathways of coagulation.

Question 11

aPTT: activated partial thromboplastin time

Answer 11

measures the time it takes plasma to clot when exposed to substances that activates the contact factors, which assesses the intrinsic and common pathways of coagulation

Question 12

INR

Answer 12

international normalized ratio): the normal range for PT varies by laboratory and reagent/instrument combination, therefore the result is always reported along with a control factor, which is the INR. INR results will be similar on a blood sample tested in any library using any thromboplastin reagent/instrument system when calibrated correctly.

Question 13

what conditions are antiplatelet agents prescribed for?

Answer 13

• Reduce risk of CVA/MI
• Reducing thrombolytic events post – CVA/MI
• Prevent DVT
• Prevent thrombi formation unstable angina/coronary stents

Question 14

Foods that interfere with coagulation: counter effects of anticoagulant

Answer 14

o Foods high in vitamin K will counter the effects of the anticoagulant
o Alcohol is high in vitamin K, as well as cranberry juice
o Kale, spinach, Brussel sprouts, collards, mustard greens, chard, broccoli, asparagus

Question 15

Foods that are natural anticoagulants

Answer 15

o Turmeric/ginger/garlic/cayenne pepper

Question 16

• Know which nursing assessments need to be performed prior to the administration of a thrombolytic and WHY

Answer 16

• Need to give thrombolytics ASAP. Ideally in less than an hour. Can be given a max of 4.5 hours after CVA has occurred.
• Obtain complete health history including allergies and drug history
• Obtain baseline vital signs
• Obtain lab values for clotting times and CBC

Question 17

• When would an anti-fibrinolytic be administered and what is important to assess for in the patient’s history prior to administration?

Answer 17

o Used to prevent and treat excessive bleeding post-op
o Usually given during or after surgery so the site will stop bleeding
o Heavy menstrual bleeding
o Displaces plasminogen from fibrin. Inhibits fibrinolysis
o Assess clotting time, CBC

Question 18

Process of Hemostasis: Three major steps

Answer 18

1. intrinsic and extrinsic pathways both lead to formation of prothrombinase
2. prothrombinase coverts prothrombin to thrombin
3. thrombin coverts fibrinogen to fibrin
4. fibrin strands trap RBCs forming a clot.

Question 19

Role of platelet in hemostasis

Answer 19

o Platelets adhere to and aggregate at site of injury in vessel
o Platelet activation leads to formation of fibrin network that trap RBCs forming clot

Question 20

Role of Cofactors in hemostasis

Answer 20

o Ca2+ and vitamin K are critical for synthesis of clotting factors

Question 21

Platelet disorders

Answer 21

• Due to decreased production resulting in low platelet counts (thrombocytopenia) – not able to clot as easily
  o Bone marrow suppression
  o Folic acid and B12 deficiency
  o Decreased thrombopoietin (in liver failure) – platelets <100
• Hemophilia and von Willebrand’s disease
  o Genetic conditions result in in absence of clotting factors  difficulty clotting

Question 22

Warfarin

Answer 22

• Reduced vit K (active vitamin K) is a cofactor for the production of clotting factors including thrombin and prothrombinase
• Warfarin inhibits two enzymes necessary for formation of reduced vitamin K.
• Monitor INR when on Warfarin

Question 23

Thrombolytics: tPA

Answer 23

Plasmin – tissue-plasminogen activator (tPA) and urokinase-plasminogen activator convert plasminogen into active plasmin which breaks down fibrin.