Bleeding And Anticoagulants

Question 1

What is the mechanism of haemostasis?

Answer 1

1. Vascular spasm
2. Platelet activation and platelet aggregation = formation of platelet plug
3. Blood coagulation (extrinsic and intrinsic pathway leading to common pathway)
4. Conversion of fibrinogen —> fibrin forms fibrin plug
5. Fibroblasts, monocytes, and other WBC that turn blood clot into fibrous scar to produce permanent dealing of the blood vessel

Question 2

what is a congenital cause of prolonged bleeding?

Answer 2

Haemophilia - this is because the level of Factor VIII in the blood is too low to complete the clotting process as described earlier.

Question 3

what is an acquired cause of prolonged bleeding?

Answer 3

therapeutic coagulations/medications

Question 4

what does warfarin interfere with?

Answer 4

vitamin K

Question 5

what is the significance of vitamin K in the clotting cascade?

Answer 5

vitamin K used by the liver to produce factors 2,7,9 and 10.

Question 6

what are DOAC’s?

Answer 6

direct anticoagulant
- apixaban, dabigatran, edoxaban, rivaoxaban

Question 7

what type of anti-fungals CANNOT be given to patients taking warfarin/statins?

Answer 7

azoles - miconazole, fluconazole

Question 8

what type of anti-fungals CANNOT be given to patients taking warfarin/statins?

Answer 8

azoles - miconazole, fluconazole

Question 9

what are the benefits of newer anticoagulants compared to warfarin

Answer 9

• warfarin takes a long time to start acting and if you stop warfarin it takes a long time to wear off
• DOAC’s act on a specific point in the pathway so they are more predictable or reliable

Question 10

what is the function of plasmin in the clotting proess?

Answer 10

it starts to break down fibrin clots - we dont want to create a blood clot that is not controlled as we will end up with blood clots that are just getting bigger and can travel up the blood vessel and can cause more damage than necessary

Question 11

what would you tell a patient taking warfarin who requires an extraction about stopping their medication?

Answer 11

DO NOT stop warfarin as the chances of causing harm is greater than

Question 12

when would you check a stable INR?

Answer 12

within 72hrs of extraction

Question 13

when would you check an unstable INR?

Answer 13

within 24hrs of extraction

Question 14

what does the INR need to be in order to carry out the extraction?

Answer 14

4 or less

Question 15

what are examples of anti-platelet drugs

Answer 15

aspirin
clopidogrel

Question 16

What does warfarin interfere with?

Answer 16

Vitamin K metabolism