ORS03 - Lecture 6 - Bleeding Risks and Haemorrhage

Question 1

What are the steps to haemostasis (blood clotting)? (5)

Answer 1

1) Injury (tissue damage) exposes the endothelium -> leaking of blood and its components

2) Vascular spasm occurs as smooth muscle constrict blood vessel wall -> reduce blood loss

3) Platelets adhere to the endothelium releasing chemicals that attract more platelets

4) Fibrogen is converted into fibrin which forms a mesh that traps platelets and erythrocytes to forming a platelet plug

5) Fibrin strands secure platelets and erythrocytes (RBCs) - effectively You then get significant fibrin clot formation via fibrinolysis

Question 2

What is coagulopathy?

Answer 2

Impaired coagulation (i.e. bleeding disorders)

Question 3

What causes coagulopathy? (3)

Answer 3

Abnormal blood vessels

Age and steroid therapy -> vessels fragile

Inherited conditions (Haemorrhage Telangiectasia, Ehler’s-Danlos syndrome)

Abnormal platelets (thrombocytopenia = ↓ no. platelets)

Causes include: idiopathic (ITP), autoimmune, liver/kidney disease, HIV/AIDS, chemotherapy, bone marrow failure, inherited (Von Williebrand’s disease or Bernard-Soulier syndrome)

Normal platelet range -> 150-400 x 10⁹/l

Minimum for LA infiltration -> 30 x 10⁹/l

Minimum for extraction -> 50 x 10⁹/l

Abnormal coagulation

Inherited diseases - haemophilia A (factor VIII) or B (factor IX), single factor deficiencies, afibrinogenaemia, Von Willebrand’s disease

Acquired diseases - liver/renal disease, HIV/AIDS, malabsorpton (vitamin K or coagulation factor), bone marrow failure, malignancy.

Drugs - anti-coagulants (warfarin, NOAC, DOAC), anti-platlets (aspirin), chemodrugs (cyclosporin), NSAIDs

Question 4

What is the function of Warfarin? (1)

Answer 4

Its a vitamin K antagonist -> inhibits the production of coagulation factors II, VII, IX, X

Question 5

How do you measure clotting time? (1)

Answer 5

Standardised prothrombine time (INR)

Question 6

Give examples of significant measurements of INR

Answer 6

Normal = 1

24 hours before extraction = <4

Warfarin (DVT, MI, atrtial fibrillation) = 2-3

Warfarin (mechanical heart valves) = 3-4.5

Question 7

Describe the warfarin protocol in KCL (6)

Answer 7

Do not stop or change warfarin dose

Risk of thromboembolic event (blood clot) > Oral bleeding

INR <4.0 24 hours before extraction

Reduce risk of bleeding -> local measures, surgicel, sutures

Avoid NSAIDs

+/- 5% tranexamic acid m/w x 4 per day for 2 days

Question 8

What are NOACs? (4)

Answer 8

New oral anti-coagulants (NOAC)

Prevents thromboembolisms and strokes

For example - Dabigatran, Rivaroxaban, Apixaban, Edoxaban

Treat patients early (AM)

Question 9

What is Transexamic acid? (4)

Answer 9

Antifibrinolytic

Prevents fibrinolysis (break down of fibrin clot)

By inhibiting activation of plasminogen to plasma (which degrades the clot)

Applied topically post-operatively using a swab or via mouthwash

Question 10

Explain how you would manage haemorrhage (bleeding) during (primary) and post-surgery (secondary) (6:5)

Answer 10

During surgery (primary) (6)

Reassure patient

Irrigate surgical site

Suture soft tissues tears

Reservable heamostats agent -> socket

Horizontal mattress suture to compress + bind mucous edges

Pressure from moist gauze (15-20mins)

Post-surgery (secondary) (5)

Administer LA (if bleeding stops - indicates temporary)

Remove any blood clot

Pack/suture as for primary

Antimicrobials

Consider underlying cause