ORAL SURG - Abnormal Bleeding Flashcards

1
Q

give instances of which there may be bleeding in a patient.

A
  • extraction
  • surgery
  • biopsies
  • trauma
  • perio, probing
  • exposure of vital pulp
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2
Q

give effects of blood loss

A
  • patient distress
  • blood in the tissues - bruise, infection
  • blood in the stomach - vomiting
  • blood in airway - obstruction
  • hypovolaemic - shock
  • reduced O2 carrying capacity
  • reduced proteins - oedema, water not kept in blood
  • reduced platelet
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3
Q

what must be checked as part of the history?

A

the bleeding/clotting history
- if there are any previous issues or medications which affect bleeding
- any liver problems

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4
Q

what local measures can be used to stop bleeding?

A
  • applying pressure
  • suturing - stitch up
  • haemostatic gel
  • surgicel - gel wrapped in gauze
  • tell patient to wait and then check
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5
Q

what MUST be delivered after a bleeding episode?

A

post-op care
follow up with the patient

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6
Q

what comes under Virchows Triad?

A
  • coagulation factors
  • blood flow
  • vessel wall
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7
Q

what happens if blood flow is too slow? when would this happen?

A

more likely to develop blood clots

  • people who dont use leg muscles
  • sat too much
  • airplanes
  • pools in lower leg
    = DVT
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8
Q

give 2 abnormalities that may be in a vessel wall

A

artificial heart valve
atherosclerotic plaque

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9
Q

what happens when a vessel wall ruptures?

A
  • VWF in the vessel wall exposed to collagen in the blood
  • platelets bind to VWF
  • platelets change shape
  • attract more platelets
  • aggregation
    -platelet plug
  • other blood proteins join
  • fibrin meshwork
    = clot
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10
Q

what if there are too many coagulation factors?

A

likely to form blood clots

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11
Q

what type of medicine is warfarin?

A

anti-coagulant

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12
Q

how does warfarin work?

A

stops liver metabolising Vitamin K
thereby liver doesn’t produce coagulation factors 2,7,9,10
- prevents the intrinsic coagulation pathway from activating

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13
Q

what is the purpose of haemostasis?

A

to prevent blood loss

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14
Q

what are the 4 steps of haemostasis?

A
  • vascular spams
  • platelet plug
  • blood coagulation
  • growth of fibrous tissue in the hole
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15
Q

what happens during a vascular spasm?

A

smooth muscle contracts
reduce diameter of lumen
reduce speed of blood flow
- helps blood to flow

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16
Q

describe the formation of a platelet plug.

A
  • platelets exposed to collagen
  • platelets release Thromboxane A2
  • aggregation
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17
Q

what does the release of Thromboxane A2 do?

A

change shape of platelets and increase the stickiness
.. more and more stick baaaahhh

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18
Q

what factor does the platelet plug activate and what does it do?

A

FACTOR 10
- activates coagulation cascade

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19
Q

give 2 anti-platelet drugs

A

aspirin
clopidrogel

20
Q

how does aspirin and clopidrogel interact with platelets in the same way?

A

they irreversibly bind

  • they’re bound until the full life cycle of the platelet
21
Q

how long is the life of a regular, non-medicated platelet?

22
Q

how long is the life of a platelet when bound to aspirin?

A

a few weeks

23
Q

what are the indications for patients who take anti-platelet drugs, aspirin or clopidrogel?

A
  • vascular disease
  • IHD
  • thromboembolic disease
  • stroke
  • those likely to have p aggregations within the vascular system
24
Q

what post-op advice should be given to patients who take aspirin?

A
  • don’t stop taking aspirin
  • risk of stopping>risk of continuing
25
what are the two pathways for the clotting cascade?
intrinsic pathway extrinsic pathway
26
describe the intrinsic and extrinsic pathway
the clotting cascade intrinsic - internal vessel wall damage - exposed collagen and platelet activation - F12, F11, F9, F8 - F10 activates into F10a extrinsic - tissue damage - F7 - F10 activates into F10a both of them: - F10a activates prothrombin into thrombin - thrombin activates fibrinogen into fibrin
27
what is the main role of most anti-coagulations?
to inhibit the action of F10
28
what 3 tests are used to test bleeding? describe each
INR - international normalised ratio - patients prothrombin time:control prothrombin time - assess' warfarin anticoagulation APTT - activated partial thromboplastin time - assess' heparin anti-coagulation Platelet Count - normal is 200-400x10^9/L
29
what is the prothrombin time?
the time taken for prothrombin to activate
30
what platelet count is a problem?
if it is lower than 100 x 10^9
31
what are the indications for patients who take warfarin?
- atrial fibrillation - heart valve abnormalities or replacement - thromboembolic disease
32
how long does it take for warfarin to work and why?
7 days because there are already coagulation factors present, it just prevents more being produced
33
which antibiotic enhances the effect of warfarin?
metronidazole
34
what clotting factors does warfarin affect?
2,7,9,10
35
what INR level is safe to perform an extraction?
<4
36
with unstable INR and a stable INR, when would you want to check the readings prior to extraction?
unstable - 72 hour window stable - 24 hour window
37
timing wise, when would it be good to extract a tooth with a patient with abnormal bleeding?
early in the week early in the day
38
with a low INR of 2-3, how many teeth can you extract at a given time?
all extractions one side at a time
39
with a INR of 3-4, how many teeth can you extract at a given time?
consider one quadrant at a time and consider the inferior dental block - possibility of hitting the inferior artery
40
what's wrong with warfarin?
- difficult to get stable anti-coagulation - interacts with different drugs - can be affected by food - constant monitoring required
41
4 pros and 2 cons of new anticoagulants.
1. single point of action 2. predictable 3. no need to monitor INR 4. doesn't interact with food 1. no antidote 2. half life up to 17 hrs
42
give the name of a 4 new anticoagulants and what factor of the coagulation cascade they work on.
warfarin - affects F7, 9 apixaban - affects F10 rivaroxaban - affects F10 edoxaban - affects F10 dabigatran - affects fibrinogen into fibrin
43
indications for new anti-coagulants
artial fibrillation thromboembolic disease stroke heart valve replacements
44
how does surgicel appear?
white gauze soaks up the blood oxidised cellulose denatures blood and turns it black
45
what prevents the breakdown of a fibrin clot?
tranexamic acid mouthwash