Hemostasis

Question 1

What is hemostasis?

Answer 1

Process that halts bleeding after injury to a blood vessel. Think:

1. platelets
2. fibrin

Question 2

Anticoagulants vs Antiplatelet drugs

Answer 2

ACs - inhibit clotting factors (fibrin formation)

APs - inhibit platelet aggregation

Question 3

In the clotting cascade, warfarin affects _____ and heparin affects ______.

Answer 3

prothrombin, thrombin

Question 4

Can anticoagulants be used on existing clots?

Answer 4

No, they are used prophylactically to stop clot formation. They do not lyse clots

Question 5

Anticoagulants Name 3

Answer 5

Heparin, LMWH (low molecular weight heparin), warfarin

Question 6

Heparin acts on the _____ pathway (intrinsic or extrinsic)?

Answer 6

Intrinsic

Question 7

Heparin dose monitored how?

What is the range?

Answer 7

aPTT, 1.5-2.5 x

since heparin dosage is different for every individual:
activated partial thromboplastin times (aPTT)
which measures the intrinsic pathway

Basically, the aPTT is a measure of how long it takes blood to clot in seconds. The goal of using heparin is to increase that patient’s clotting time to 1.5 - 2.5 times as long as it would take a normal person to clot.

Question 8

What is HIT?

Answer 8

Heparin-induced thrombocytopenia

1-5% of pop

Question 9

what antidote can reverse the anticoagulant effects of heparin?

Answer 9

protamine sulfate

Question 10

LMWH
Name one
Pros
Inhibits?

Answer 10

Enoxaparin

Dose doesn’t change from person to person
more predictable anticoagulant response
doesn’t require frequent lab monitoring

Inhibits only Factor Xa (not directly on thrombin)

Question 11

Heparin SC site?

Answer 11

Abdomen only

Question 12

Warfarin is a _____ __ antagonist

Answer 12

Vitamin K

Question 13

What does Vitamin K do?

Answer 13

It binds to an enzyme, and that enzyme can then convert clotting factor precursors into “ready for action” factors

Question 14

Heparin vs warfarin - Which one acts more quickly/do we see the effects of more quickly?

Answer 14

Heparin acts within minutes, warfarin takes 3-5 days to see an effect

Question 15

Warfarin route of administration?

Answer 15

Orally only

Question 16

Warfarin monitored how?

Answer 16

PT/INR 
prothrombin test (PT) and the international normalization reference ratio (INR)

Question 17

PT range

INR range

Answer 17

PT 1.3-1.5 x

INR 2-3 x

Question 18

Warfarin acts on the _____ pathway (intrinsic or extrinsic)?

Answer 18

Extrinsic pathway

Question 19

Warfarin
client education
contraindication**

Answer 19

ed - keep intake of vitamin K constant (dark leafy greens, tomatoes)
cont - pregnancy

Question 20

What does DOAC stand for

Answer 20

Direct-acting Oral AntiCoagulant

Question 21

DOACs

1) Thrombin inhibitor
name one
pros (think of all the warfarin cons)
administration

2) Factor Xa Inhibitor
name one

Answer 21

1) Dabigatran
rapid onset, fixed dose, no blood tests, few drug-drug interactions, no dietary concerns
Oral

2) Rivaroxaban
Same pros as dabigatran, also oral

Question 22

Antiplatelet Drugs

name 3

Answer 22

ASA 81 mg irreversibly inhibits COX in a platelet cell, and COX activates the platelet

Clopidogrel irreversibly blocks ADP receptor, ADP also activates platelets

Question 23

Thrombolytic Agents
name one
indication
adverse effect

Answer 23

break down clots - tPA produces plasmin, and plasmin goes around chomping up clots
tPA - alteplase
(recombinant tissue plasminogen activator)

used to re-establish blood flow in MI and stroke

dysrhythmia