Question 15.1

College Answer

a) What is the likely diagnosis?
Supratherapeutic warfarinisation

b) Outline your management of this patient?
If not bleeding:
Stop warfarin
Vitamin K
Consider FFP or prothrombinex if high risk of bleeding

If bleeding:
Resuscitation
Stop warfarin
Vitamin K in as low a dose as possible
FFP 10-15ml/kg or prothrombinex 20-25IU/kg

Discussion

This question stems from guidelines for the reversal of anticoagulation.

 It does not take a great deal of cognitive effort to deduce that this AF patient must be on warfarin, and the high INR suggests he has had a little too much.

The model answer for management is derived from anticoagulation reversal guidelines, which vary from place to place but ultimately derive from the 2004 MJA article I have referenced below. Certainly, my local reversal guidelines seem to be based on this. A brief entry on the reversal of anticoagulant therapy deals with this mundane irritation in slightly more detail. In brief, the general trend is to follow various published consensus statements.

Thus:

• INR 4.5 – 10.0 and no bleeding: stop warfarin
• INR 4.5 – 10.0 and high risk of bleeding: Vitamin K (1 – 2 mg orally or 0.5 – 1.0 mg iv).
• Immediate reversal: Prothrombinex 25 – 50 iu/kg.
• Acutely bleeding: high dose of Vitamin K - 5-10mg IV. It does not matter what the INR is.
• Haemorrhage into a critical organ: 5-10mg of Vit K and prothrombinex 50.0 units/kg, and FFP 150–300mL.
• FFP is generally reserved for situations when the prothrominex is not readily available. The maximum dose is 15ml/kg.

Thus, one would merely withhold warfarin for a patient with low risk of bleeding. If the risk of bleeding is high, one would give vitamin K or FFP/prothrombinex. If bleeding has already occurred, one would resuscitate the patient and also give FFP/prothrombinex.

Ross I Baker, Paul B Coughlin, Hatem H Salem, Alex S Gallus, Paul L Harper and Erica M Wood Warfarin reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis Med J Aust 2004; 181 (9): 492-497.

There is also this local policy document.