Coagulation A Surgical Perspective (Exam III) Flashcards by Annabella Moody

What events occur in primary hemostasis (3)

1- vasoconstriction
2- platelet activation
3- platelet plug formation

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What events occur in secondary hemostasis (2)

1- coagulation cascade
2- formation of fibrin clot

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What molecule degrades the blood clot after it has done its job

Plasmin

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What event initiates hemostasis

Vascular injury

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What are three phases of hemostasis (normal)

1- vascular phase
2- platelet phase
3- coagulation phase

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What causes the vasoconstriction following injury to a blow vessel

Vascular spasm

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First step of the platelet phase

Exposed collagen bind and activates platelets

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What is the second step of the platelet phase

Release of platelet factors

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In the third step of the platelet phase after the release of platelet factors

Attracts more platelets

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In the final step of the platelet phase

Platelet plug forms

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The plug formed in the platelet phase is:

Loose and temporary

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What molecule do platelets bind during the platelet phase

Collagen

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What pathways make up the coagulation phase

Intrinsic and extrinsic and common

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The common pathway ultimately leads to

Cross-linking of fibrin

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Name the pathway that involves the conversion to fibrinogen to fibrin

Intrinsic and extrinsic

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Drug that affects clotting

Warfarin

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Drug that affects platelets

Aspirin

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When someone has issues with ____ this results in a bleeding issue

Platelets

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Partial or complete dissolution of the hemostatic plug by plasmin

Fibrinolysis

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What activates plasmin

Thrombin

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List factors affecting a normal hemostasis mechanism (5)

1- vessel wall integrity
2- adequate numbers of platelets
3- proper functioning of platelets
4- adequate levels of clotting factors
5- proper function of fibrinolytic pathway

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You cannot perform oral surgery if the platelet count is:

Less than 50,000

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Normal platelet range

150,000-400,000

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People with a normal number of platelets (150-400k) can still have

Issues with platelet function

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What medications can affect platelet function

Aspirin Plavix

When someone has a platelet deficiency what can be an effective treatment

Platelet diffusion

Clotting disorders to be aware of as a clinician

Hemophilia A or B

Hemophilia A involves clotting factor

VIII

Hemophilia B involves clotting factor

Platelet count is measured in a

CBC

Common laboratory tests to evaluate hemostasis

Platelet count Bleeding time Coagulation profile

What tests make up the coagulation profile (3)

1. Prothrombin time (PT) 2. Activated partial thromboplastin time (APTT) 3. Internationalized normal ration (INR)

Advanced tests used to evaluate hemostasis (2)

1. Platelet function tests 2. Clotting factor assays (II-XII)

A test that may be recommended for those who bruise easily, have excessive bleeding or taking medications following stroke or heart attack that can alter platelet function

Platelet function test

Test that measures the levels of functional activity of one or more coagulation factors

Clotting factor assays (II-XII)

Standard range for WBCs

4.5-11.0

Standard range for RBCs

3.5-5.5

Standard range for Hgb

12-15

Standard platelet range

150,000-400,000

A platelet count of 100,000-140,000 indicatives

Thrombocytopenia

An individual with a platelet count of 100,000-140,000 diagnosed with thrombocytopenia will have a bleeding time that is

Normal

What type of procedures can you perform on an individual with mild thrombocytopenia (Platelets 50,000-100,000)

Simple extractions, no major surgeries

An individual with a platelet count of 50,000-100,000 is considered to have

Mild thrombocytopenia

An individual with mild thrombocytopenia (platelet count 50,000-100,000) will have what kind of bleeding time

Mildly prolonged

An individual with a platelet count of less than 50,000 is considered to have

Severe thrombocytopenia

What type of oral surgery procedures can you perform on a patient with severe thrombocytopenia

You cannot

Individuals with a platelet count of less than 20,000 will have

Spontaneous bleeding

How long should it take a precise nick to stop bleeding

2-9 minutes

Normal bleeding time

2-9 minutes

Bleeding time provides an assessment of

Platelet function

A bleeding tie mom 9-15 minutes is indicative of

Platelet dysfunction

What test measures the effectiveness of the extrinsic pathway

Prothrombin time (PT)

The prothrombin time test measures the rate of conversion of

Factor VII-VIIa

Normal prothrombin time

12-13 seconds

What are common causes for prolonged prothrombin time (3)

1- warfarin use 2- vitamin K deficiency 3- liver disease

Test that measures the effectiveness of the intrinsic and common pathway

Activated partial thromboplastin time (aPTT)

Test that measures the intrinsic clotting of blood and congenital clotting disorders

Activated Partial Thromboplastin Time (aPTT)

Considered a more sensitive version of the PTT and is used to monitor the patients response to heparin therapy

APTT

Normal time frame for APTT

30-40 seconds

If a patient has an aPTT of more than 70 seconds that signifies

Spontaneous bleeding

Congenital deficiencies of intrinsic system clotting factors such as factors VII, IX, XI, XII including hemophilia A, and hemophilia B can cause a prolonged

APTT

Most commonly inherited bleeding disorder affecting patient function

Von Willebrand disease

What makes most of the clotting factors, including the vitamin K-dependent ones

Liver

Liver cirrhosis can cause a prolonged

APTT

The synthesis of some clotting factors requires vitamin K so vitamin K deficiency results in an inadequate quantity of intrinsic system and common pathway clotting factors resulting in a prolonged

APTT

Inhibits the intrinsic pathway at several points

Heparin therapy

Heparin therapy results in a prolonged

APTT

Inhibits the function of factors I, IX, and X, prolonging the APTT

Coumadin therapy

Congenital deficiencies of intrinsic clotting factors (8,9,11,12) Von Willebrand disease Liver Cirrhosis Vitamin K deficiency Heparin therapy Coumadin therapy People affected by any of these will have a:

Prolonged aPTT

INR stands for

International normalized ratio

INR equation is

Patient PT / mean normal PT and raised to the ISI

ISI stands for

International sensitivity index

The ISI value is normally between

1-2

Normal INR level

0.8-1.2

Therapeutic INR level

2-3.5

An INR range of 2.5 (2-3) is the goal for all of the following circumstances (7)

Atrial fibrillation (AF) Transient ischemic attack (TIA) Ischemic stroke Systemic embolism Mitral stenosis Planned cardio version After open heart surgery

We want a slightly higher INR of around 2.5 for patients with conditions that could make them

More prone to a blood clot

1. Bleeding time 2. Prothrombin time 3. APTT 4. INR 5. Therapeutic INR

1: 2-9 minutes 2: 12-13 seconds 3: 30-40 seconds 4: 0.8-1.2 5: 2-3.5

What bleeding disorders are more common (congenital or acquired)

Acquired

Someone taking Ibuprofen, Aspirin or NSAIDs can be at risk for

Compromised platelet numbers

What three congenital bleeding disorders constitute over 90% of all bleeding congenital bleeding disorders

Hemophilia A Hemophilia B Von Willebrands disease

What has a higher prevalence - hemophilia A or B

A (1 in 10,000)

Both hemophilia A and B are inherited in a

Sex-linked recessive manner

What sec does hemophilia affect more frequently

Males

Bleeding in between joints

Hemoarthrosis

The biggest concern is when people have ____ case of hemophilia

Mild

Why is mild hemophilia of great concern

Because typically patients are unaware

What is prepared from plasma and contains fibrinogen, fibronectin, Von Willebrand factor, Factor 8 and Factor 9 and is given to patients through IV

Cryoprecipitate

Desmopressin could be given to a patient with

Hemophilia A

What part of hemostasis does Von Willebrands disease effect

Primary

There are three types of Von Willebrands Disease: Type I involves: Type II invovles: Types III involves:

Type I - shortage of VWF Type II - flawed VWF Type III- absent VWF

Most common form of VWD

Type I

The two causes of thrombocytopenia

1- decreased platelet production 2- increased platelet destruction

If a patient is on oral anticoagulant/antiplatelet treatment are they recommended to stop use prior to a minor oral surgery procedure?

The decision to hold an anticoagulant/antiplatelet therapeutic drug can only be made by

Physician (NOT dentist)