Coagulation Flashcards

1
Q

Hemostasis

A

Stopping the flow of blood

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2
Q

What does hemostasis prevent

A

The minor bumps and bruises of daily life from being fatal

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3
Q

What are the three phases of the separate mechanisms?

A

Mechanical phase
Chemical phase
Final Phase

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4
Q

What two responses make up the mechanical phase?

A

Vascular response

Platelet response

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5
Q

Vascular response

A

The arteries and arterioles contract and reduce the size of the lumen when the vessels are damaged

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6
Q

What does the constriction of the vessels do?

A

Decreases blood flow so less blood is lost

Turbulence activates platelets

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7
Q

Platelet response

A

When the platelets hit connective tissue or injury they activate and become sticky, grabbing onto each other, creating a plug

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8
Q

von Willebrand’s factor

A

Required for platelets to stick to the site of injury

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9
Q

Chemical phase

A

Coagulation mechanism response aka clotting cascade

Involves a number of clotting factors

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10
Q

What two pathways does the chemical phase involve?

A

Intrinsic and extrinsic pathways

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11
Q

What does the chemical phase result in?

A

Fibrinogen being converted into fibrin

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12
Q

Final Phase

A

Degradation of the fibrin clot

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13
Q

Coagulation Mechanism Response or Clotting Cascade

A

Fibrinogen and other substances in the blood are inactive and when activated they change from a liquid to a semi-solid substance

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14
Q

When activated, what are fibrinogen and other substances called?

A

Clotting factors
Numbered I-XIII
VI is missing

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15
Q

Activation of clotting factors: Intrinsic Pathways

A

Activated without tissue contact

Example: IV Catheter placement without proper anti-coagulant

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16
Q

Activation of clotting factors: Extrinsic Pathways

A

More commonly activated

Activated with tissue contact outside of the blood vessel (injury)

17
Q

What is important to remember in sample collection for coagulation?

A

Minimize tissue damage

Minimal venous stasis

18
Q

Why must you never use an indwelling catheter to obtain a sample for coagulation testing?

A

Because it may have fibrinogen, fibrin, and platelets around the catheter

19
Q

What is the preferred method to collect blood for coagulation testing?

A

Vacutainer or monovette

The proper ratio of anticoagulant to blood

20
Q

Coagulation tests: aPTT

A

Activated partial thromboplastin time

21
Q

What does aPTT measure?

A

The contact activation (intrinsic) pathway is initiated by the activation of the “contact factors” of plasma

22
Q

Coagulation tests: PT

A

Prothrombin time test

23
Q

What does the PT test measure?

A

The tissue factor (extrinsic) pathway is initiated by the release of tissue factor

24
Q

In-House Analyzers

A

Use fresh or citrated anticoagulated blood

IDEXX Coag DM; Q-labs Insight

25
Thromboelastograph
Measures initial clot to fibrinolysis Clot formation time Strength of clot Breakdown time
26
Platelet Function Analyzers
Assessment of platelet adhesion and aggregation Blood is drawn through an aperture and platelets adhere to the membrane Measures the time it takes to occlude aperture with platelets is recorded