HAEMOSTATIS AND COAGULATION
Haemostasis is the arrest of bleeding following vessel injury
1) Changes in involved vessel
Formation of platelet plug
Formation of fibrin clot
Vessel vasoconstricts
Endothelium becomes 'procoagulant'
Vessels where I VSM present (not capillaries - endothelium fuses)
Mechanisms:
- depolarisation of vascular smooth muscle cells
- vasoactive mediators
ANTICOAGULANTS
HEPARINS
Types
LMWH (low molecular weight heparins)
Protamine
ORAL ANTICOAGULANTS
DIRECT FACTOR Xa INHIBITORS
WARFARIN
DIRECT THROMBIN INHIBITORS :
Naturally occurring heparin
UFH (Unfrationated Heparin)
Highly sulphated glycoasaminoglycan.
Anionic
MW variable = 5000-30000 Da
Production - basophils, mast cels
Chemical: synthetic. MW 5000-25000 Da
Uses: treat VTE, unstable angina, critical arterial occlusion, extracorporeal circuits (bypass, ECMO)
Action: potentiates antithrombin (III), inhibitis Xa, inhibits platelet aggregation at high levels
oute: IV infusion
Chemical: synthetic heparin MW 5000-30000 Da.
Uses:
- treatment of DVT/PE
- critical arterial ischaemia
- extracorporeal circuits (dialysis, bypass, ECMO)
Actions:
1) potentiates Antithrombin (III) - forms inactive complex with thrombin
2) inhibits Factor Xa
3) inhibit platelet aggregation at high concentration
Dose:
Route:
Side effects:
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