Haemostasis

Question 1

how long is the half life for warfarin?

Answer 1

40 hours

Question 2

how long does it take warfarin to take action?

Answer 2

1-2 days

Question 3

how is warfarin potentiated?

Answer 3

liver disease
decreased vit K
drugs which interfere with liver function eg sulphonamides
drugs which displace it from plasma protein eg aspirin

Question 4

how is warfarin action inhibited?

Answer 4

drugs which induce the p450 system eg barbituartes

Question 5

how does warfarin work?

Answer 5

it prevents the action of Vit K carboxylates factors 2,7,9,10

coumarin derivative

Question 6

how does heparin work?

Answer 6

activates and bonds antithrombin 3

Question 7

what is the purpose of antithrombin 3?

Answer 7

antithrbombin 3 inhibites 2a and 10a (more potent at 10a))

Question 8

how is heparin administered?

Answer 8

IV since large MW and positive charge

LMW heparin can be adminstered SC

Question 9

how does aspirin work?

Answer 9

alters the balance between thromboxane A2 and PGI2.

Causes decrease in TXA2 and increase in PGI2

Question 10

what is the function of TXA2?

Answer 10

promotes platelet aggregaton

Question 11

what is the function of PGI2?

Answer 11

inhibits aggregtion

Question 12

how can haemorrgahe be classified?

Answer 12

immediate
reactionary (<48hours)
delayed

Question 13

causes of haemorrhage?

Answer 13

Developmental: 
Trauma
Infective
Iatrogenic
Neoplastic
Pathogenic
Drugs

Question 14

how does infective causes of haemorrhage usually present?

Answer 14

7-10 days post op

delayed

Question 15

what are the pathogenic caused of haemorrhage?

Answer 15

platelet: thrmbocytopaenia/pathy
cloting cascade
vessel wall

Question 16

what are the pathogenic causes of clotting cascade induced haemorrhage?

Answer 16

Inherited:Haemophilia A/B
von willbrand disease (lack of VWF)

Acquired: Warfarin, Heparin, Aspirin, Live disease, DIC

Question 17

what are the pathogenic causes of platelet induced haemorrhage?

Answer 17

thrombocytopaenia

thrombocytopathy

Question 18

what are the pathogenic causes of vessel wall induced haemorrhage?

Answer 18

HHT
VED
Haemaginoma
Scruvy
Anaphylactoid pupura
Eherls Danlos

Question 19

how does clotting occur?

Answer 19

Extrinsic tissue: PT (12-15 s)
Intrisic foriegn body) APTT 25-45 s
prothrombin --> thrombin
firbinogen --> firbin
fibrinlosysis: PLasminogen--> plasmin

Question 20

when is warfarin used?

Answer 20

AF/prostethic heart valves

Question 21

how is heparin reversed?

Answer 21

protamine suplate

Question 22

when is heparin used?

Answer 22

Post op DVT to prevent it

Question 23

what are the clinical signs of blood loss?

Answer 23

INcreased heart rate
Decreased BP
Cold pale extremeties

Question 24

what parecentage of blood needs to be lost before signs are noticed?

Answer 24

10%

Question 25

what systemic medications can be given to people during heamorrgahe?

Answer 25

FFP
Vit K
Clotting factors
Desmopressin
tranexamic acid

Question 26

what complication may arise from haemaorrgahe?

Answer 26

Hypovolaemic shock

needs fluids or blood transfusion

Question 27

what problems can arise from Retromaxilliary heamorrhage?

Answer 27

Airway obstruction and hypovolaemic shock

Question 28

What problems may airse from retrobulbar haemorrhage?

Answer 28

Blindness

Question 29

what problems may arise from intracranial haemorrhage?

Answer 29

brain damage and decreased pulse rate, increase BP and increase ICP

Question 30

when treating haemophiliacs, what should you consider?

Answer 30

use infiltration and intraligementals where possible
prescribe AB: prevent secondary infection
tranexamix acid
pack and suture