Abnormal bleeding Flashcards by Agnes Zlotnicka

In what situations do we have expected bleeding associated with dentistry?

Tooth extraction
Surgery, biopsies and trauma
Periodontal therapy (and even probing)
Exposure of vital pulp
Spontaneous (local and systemic causes)

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list the Effects of Blood Loss

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list the different aspects of managing bleeding

BE PREPARED
Patient expectations
Check bleeding/clotting history
Careful surgical technique
Local measures
pressure
suture
“Surgicel”
Patience
Careful post-op care and follow-up

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draw out virchows triad

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what is virchows triad

the triad of factors that impact in the coagulation of blood

changes in any of these 3 factors can either increase or decrease the risk of bleeding

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What type of blood flow (abnormal) will promote bloodclot formation?

slow bloodflow
turbulent
if theres lots of obstruction of the blood flow

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give an example of a blockage caused by slowed down blood flow

deep vein thrombosis

on long flights or long car journeys, not using leg muscles, blood in their feet is not being pumped up by the calf muscles, so it can coagulate and end up with a DVT.

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what are most coagulation factors produced by?

the liver

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There will be questions in the exam about virchows triad so get it in ur head

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what is the purpose of haemostais?

prevention of blood loss

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when does haemostasis happen?

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list the (4) diff mechanisms of haemostasis

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haemostasis - vascualr spasm describe what it does

prevents excessive blood loss in the body
smooth muscle in the blood vessel wall contracts and reduced blood loss

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After vascular spasm, we have formation of a platelet plug.

Describe the (3) aspects of this process

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the formation of the platelet plug leads to the activation of a certain factor + 1 more molecule

what are these?

factor X and prothrombin

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Explain how aspirin works (in terms of being a blood thinner)

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Explain how clopidogrel works (in terms of being a blood thinner)

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Explain how ibuprofen works (in terms of being a blood thinner)

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how long can it take for the (blood thinning) effect of aspirin to wear off?

weeks

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it takes weeks for aspirin to wear off

howis this relevant clinically?

a lot of patients can ask “shall i stop taking my aspirin before u extarct my tooth tomorrow” - and answer is there is no point

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which type of patients are likely to be taking clopidogrel or aspirin?

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the clotting cascade - how many pathways are there?

2 - intrinsic and extrinsic

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the clotting cascade - the final common pathway involves the activation of what factor?

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why is the relevance does the common pathway have in the new oral anticoagulants?

a lot of them inhibit the activation of factor 10

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the clotting cascade- X----Xa leads to conversion of what to what?

prothrombin -----> thrombin

the clotting cascade- leads to conversion of what to what?

fibrinogen ----> fibrin

the clotting cascade: why is fibrinogen ----> fibrin important?

this is what forms a fibrin blood clot (through crosslinking of molecules)

How do we test of bleeding function (3 ways)

- INR (international normalised ratio) - platelet count - APTT (activated partial thromboplastin time)

out of the 3 ways of testing bleeding, which do do we use on a daily basis?

- INR (international normalised ratio) - platelet count

what type of patients is APTT used for?

- those using heparin

what is INR a ratio of?

prothrombin time

patients taking warfarin will be using which method of testing bleeding?

- prothrombin time checked (INR)

what does prothrombin time actually tell you

how long it takes for the prothrombin to be activated

if ur INR ratio is 2 - what does this tell u about the amount of time it takes ur blood to clot?

it takes twice as much time to clot than u expect it to

if ur INR ratio is 3 - what does this tell u about the amount of time it takes ur blood to clot?

it takes 3x as much time to clot than u expect it to

what is a normal platelet count a patient should have?

in terms of platelet count, what does the number of platelets have to be for it to really become a problem?

which patients are likely to be taking warfarin?

explain how warfarin works

warfarin - how long does clotting factor live up to?

up tp 60h

when can full impact of warfarin be seen? after how many days?

many antibiotics enhance the effect of warfarin - name one

metronidozole

what clotting factors does warfarin effect?

2, 7, 9, 10

At what INR level is it safe to perform tooth extraction on a patient?

<4.0

stable INR is okay to check within how many hours?

within 72h of taking tooth out as pt is stable therefore this INR will probably stay the same

unstable INR is okay to check within how many hours?

within 24hrs of taking tooth out

What does a patients oral anticoagulant therapy record book say?

- what the pt is taking - why they're taking it - target INR of pt - what their INRs have been over the past year

how do we check is a pts INR is stable or not?

check oral anticogulant record book (yellow book) see if it is stable if going up and down a lot and also see if warfarin dose is changing a lot or not

at what INR is it safe to perform a tooth extraction?

<4.0 but consider what u are extracting

why would we try getting extarctions in early on in the day or week?

so that if the pt does have any problems u can get them sorted out during working hours

for a pt with an INR of 2.0-3.0 how many extractions can u do at a time?

probably all extractions at one side at a time

for a pt with an INR of 3.0-4.0 how many extractions can u do at a time?

one quadrant at a time take caution with IDB maybe consider not surgical but only forceps extraction

after extraction what can u put into socket to promote a blood clot?

surgicel suture

whats wrong with warfarin?

- difficult to get stable anti-coagulation - multiple interactions with drugs and food - need for monitoring

list the drugs that warfarin interacts with

what food does warfarin interact with?

cranberry juice

whats good about the new antiocoagulants?>

- they have a much more predictable effect - tend to inhibit specific parts of the clotting cascade rather than the whole thing (like in warfarin) - they are much safeer

what type of patients take the new anticoagulants?