2020A06Describe how the effects of warfarin can be reversed when URGENT surgery is indicated (40%).
For each option discuss the advantages and disadvantages (60%).

Intro:

Mechanism	· Vitamin K epoxide reductase inhibitor
Factors affected (half life)	· Procoagulants: II (60h), VII (6h), IX (24h), X (36h) · Anticoagulants: protein C (8h), protein S (30h)

Reversal options:

Expectant	· Offset in 5 days · Allows elimination of drug + production of coagulation factors · Can operate immediately if a) low risk of bleeding b) benign consequences of bleeding c) easily compressible site · Pro: ↓risk thrombotic events, less disruptive to patient · Con: ↑risk surgical bleeding
Vitamin K	· 2mg IV (6-12 hours), or 5-10mg PO (12-24 hours) · Promotes production of new factors · Pro: fairly rapid reversal, obviates risks of blood products · Con: insufficient if very high INR or if active bleeding, difficult to restart warfarin after a big dose of Vitamin K
FFP	· Contains all clotting factors · IV 15-30mL/kg (or 2-4mL/kg if with prothrombinex) · Pro: immediate · Con: risk of TACO, risks of allogeneic transfusion
Prothrombinex	· Contains factors 2, 9, 10 · IV 25-50 units/kg · Preferred over FFP in Australia · Pro: immediate, universally compatible · Con: factor 7 absent
FEIBA	· Contains factor 7a > 2,9,10 · IV 50-100 units/kg · Pro: contains all deficient coag factors · Con: less data for warfarin reversal
Novoseven	· Factor 7a · IV 50mcg/kg · Only if persistent uncontrollable haemorrhage despite all other physiological, pharmacological and surgical efforts · Pro: immediate · Con: very expensive, short half life, high risk of thrombotic complications

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