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OSCE > Abnormal bleeding and warfarin > Flashcards

Abnormal bleeding and warfarin Flashcards

1
Q

What dentistry procedures are associated with bleeding?

A
  • Extractions
  • Surgery, biopsies and trauma
  • Periodontal therapy (probing too)
  • Exposure of vital pulp
  • Spontaneous (local and systemic causes)
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2
Q

What are the effects of blood loss?

A
  • Patient distress
  • Blood in tissues
  • Blood in stomach (vomiting)
  • Blood in airway (obstruction)
  • Hypovolaemia - reduced blood volume - shock low BP
  • Reduced oxygen carrying capacity (Hb decreased)
  • reduced protein (water holding, clotting)
  • Reduced platelets (less capacity to arrest haemorrhage)
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3
Q

How do we prepare for bleeding?

A
  • Manage patient expectations - tell patient of risks
  • Check bleeding/clotting risks
  • Careful surgical technique - being as conservative as possible, least amount of extractions at a time
  • Local measures - pressure, suture, surgicel, patience
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4
Q

How does bleeding reduce with Virchow’s triad in mind?

A

Pressure - stops blood flow
Suture - secures clot in place and holds surgicel

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5
Q

How does surgicel work?

A

It is foreign so activates the clotting cascade

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6
Q

What are the mechanisms of haemostasis?

A
  • Vascular spasm
  • Platelet plug
  • Blood coagulation via extrinsic and intrinsic pathway
  • Growth of fibrous tissue in the hole in the vessel permanently by fibroblasts
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7
Q

How does a platelet plug form?

A

Platelet adhesion - platelets adhere to exposed collagen
Release of thromboxane A2 causes increased stickiness
This causes nearby platelets to adhere to platelet plug which activates coagulation cascade by activation of factor X and prothrombin.

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8
Q

What would aspirin and clopidogrel be prescribed for?

A

They are common anti-platelets prescribed for ischaemic heart disease/recent strokes.

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9
Q

How does aspirin work?

A

Irreversibly - it effects all platelets you have and doesn’t wear off. To reverse it needs all the platelets to die off - weeks to occur.
It binds to platelet COX (cyclooxygenase) required for thromboxane A2 mediated aggregation.
Reduces chance of platelet plug

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10
Q

How does clopidogrel work?

A

Binds to the P2Y12 receptor irreversibly and prevents ADP mediated aggregation.
Reduces chance of platelet plug

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11
Q

Why would patients take anti-platelets?

A
  • Vascular disease
  • Ischaemic heart disease
  • DVT
  • Stroke
  • Peripheral vascular disease
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12
Q

Should we stop aspirin for those needing extractions?

A

NO
Takes weeks for effect to be reversed, risk of stopping is greater than risk of strokes, ischaemia, peripheral heart disease

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13
Q

What triggers the intrinsic and extrinsic pathway?

A

Intrinsic - exposed collagen and platelet activation
Extrinsic - tissue damage

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14
Q

What happens at the final common pathway?

A

Activating factor X to factor Xa catalysing prothrombin to thrombin in which fibrinogen changes to fibrin.

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15
Q

What are tests of bleeding function?

A

-INR (international normalised ratio)- Patient’s prothrombin time/control prothrombin time, assessing warfarin anticoagulation
-Platelet count
- APTT (activated partial thromboplastin time) - assesses heparin anticoagulation
- Bleeding time (direct cut - rarely used)

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16
Q

Why would a patient be on warfarin?

A

Atrial fibrillation
Heart valve abnormalities or replacement
Thromboembolic disease (DVT or pulmonary embolus)
Some other cardiac and vascular abnormalities including patients with ischaemic heart disease.

17
Q

How does warfarin work?

A
  • prevents action of vitamin K produced in the gut by bacteria
  • vitamin K is required in the liver to produce factors II, VII, IX and X
  • Warfarin prevents carboxylation of clotting factors
  • clotting factor half lives vary up to 60hrs
  • Changes to warfarin level can take 7 days
  • Long delay when drug is stopped - 7 days
  • Many antibiotics enhance effect of warfarin eg metronidazole - gut affected so can affect vitamin K can make pt more or less likely to form blood clots
18
Q

What INR is safe to perform extraction?

A

4 or less

19
Q

What should you ask a pt who takes warfarin?

A
  • Get them to show you their orange book
  • Why are they taking warfarin?
  • What their prescriber wants their INR to be
  • Every month what their INR was
20
Q

When checking the INR when is safe to perform an extraction?

A

If their INR is stable, check INR 72 hrs before extraction
IF not check within 24 hours

21
Q

When planning an extraction for a pt on warfarin when should it be?

A

Early in the week and early in the day so if the pt has problems they can get in touch.
Make sure you explain there is a risk of bleeding and what they should do if they notice any?

22
Q

How many extractions can you do with patient on warfarin?

A

INR 2-3 consider one side at a time as many extractions you can do.
3 -4 - forceps extraction one quadrant at a time
Be careful with ID blocks on patients with warfarin - do articaine infiltration

23
Q

What local measures do we use to keep a clot?

A

Surgicel
Suture

24
Q

How long should we keep a patient after XLA?

A
  • 15-20 mins and give them instructions and contact info if they notice bleeding
25
Q

What is wrong with warfarin?

A

There are multiple interactions with drugs (antibiotics, carbomazepine, antifungals, St Johns wart)
Food interactions - cranberry juice

26
Q

Who takes the new oral anticoagulants (DOAC’s)?

A

AF
Thromobembolic disease (DVT/PE)
Heart valve replacement
CVA/ strokes

27
Q

What factors do DOAC’s work on?

A

Apixaban and rivaroxaban - 10-10a
Dabigatran - fibrinogen to fibrin

28
Q

How do we manage patients on DOAC’s when extracting?

A

Check SDCEP guidelines, with DOAC’s taken twice a day we may consider emitting morning dose but in general we dont stop the medication.

29
Q

With patients with coagulopathies what do you do in regards to extractions?

A
  • Have you ever had any problems with bleeding/bruising any medications to thin the blood.
  • Get in touch with haemotologist/GP
  • Take blood tests beforehand - ask GP to check clotting factors, INR, APTT, platelet count
30
Q

How do you promote a blood clot in these patients after XLA?

A

Get pt to bite down on gauze - slows blood flow and promotes clot
Surgicel - oxidised cellulose and tranexamic acid - can stabilise blood clot in socket
Figure of 8 suture gives compression on gingivae
Oxidised cellulose - sheet of fabric that creates acidic environment that activates platelet and clotting cascade.

31
Q

What are low risk bleeding procedures?

A

Simple extractions (1-3 teeth, with restricted wound size)
Incision and drainage of intra oral swellings
Detailed 6ppc
RSD
Direct or indirect restorations with subgingival margins

32
Q

What are high risk bleeding procedures?

A

Complex extractions, adjacent extractions that will cause a large wound or more than 3 extractions at once.
Flap raising procedures:
- Periodontal surgery
- Elective surgical extractions
- Preprosthetic surgery
- Periradicular surgery
- Crown lengthening
- Dental implants
- Gingival recontouring

33
Q

When should we not interrupt anticoagulant or antiplatelet therapy for?

A
  • Patients with prosthetic metal heart valves or coronary stents
  • Patients who have had a pulmonary embolism or DVT in the last 3 months
  • Patients on anticoagulant therapy for cardioversion
34
Q

What should we do for all patients taking anticoagulants/antiplatelets requiring dental treatment likely to cause bleeding?

A
  • Plan treatment for early in the day/week
  • Provide pre-treatment instructions
  • Treat atraumatically as possible, use local measures and discharge when haemostasis is complete
  • If travel time to emergency care is concern emphasise the use of measures to avoid complications
  • Provide patient with post treatment advice and contact details for emergency
35
Q

What do you advise a patient to do for a higher risk of bleeding complication who is taking apixaban or dabigatran?

A
  • They will be taking this 2x a day, miss morning dose but take the usual one same time in the evening.
36
Q

What do you advise a patient who is taking rivaroxaban or edoxaban?

A

1x a day
If they take it in the morning - delay morning dose until 4 hours after haemostasis has been achieved
If they take it in the night - take it as usual

OSCE (6 decks)

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