Warfarin Wednesday

Hey everyone,

After a somewhat heated (well as heated as us third years can get these days) conversation in small group regarding the epistaxis pt with a supra-therapeutic INR I decided to share some info regarding INR reversal based on the current guidelines.
Things to consider:
  • Evidence of active bleeding
  • Magnitude of INR
  • Indicatino for anticoagulation
  • RFs for bleeding
    • Recent bleed w/in 4 wks, surgery w/in 2 weeks, Plt < 50, Liver disease, antiplatelets
  • Volume status?
  • Vitamin K PO and IV- Warfarin is a VitK antagonist so makes sense right?
    • Similar affects between PO and IV at 24hrs but IV has onset of 6-8hrs
  • FFP- Includes all coagulation factors, has an INR of 1.6
    • VitK dependent factors in concentration of 1U/mL
    • In a 70 kg Patient: 1 Unit Plasma increases most factors ~2.5% 4 Units Plasma increase most factors ~10%
  • PCC (Prothrombin complex concentrate) 3 has Factor 2,9, 10, 4 has 7 also... we only have 4 in our ED I believe.

Bleeding Patient:
  • INR >1.5 w/ life threatening bleed ( ICH, GI, hemodynamic instability)
    • VitK 5-10mg IV
    • PCC 50IU/kg IV AND FFP 150-300mL
      • If PCC unavailable then 15mL/kg of FFP
  • INR >2 w/ clinically significant but not life threatening bleed
    • VitK 5-10mg IV
    • PCC 35-50 IU/kg IV
  • Minor bleeding:
    • Low risk? Rpt INR next day
    • High Risk or INR >4.5 PO VitK 1-2mg or IV 0.5-1mg and close followup w/in 24hrs

NOT Bleeding:

  • INR <4.5 Omit next dose, resume at lower dose when INR is therapeutic
  • 4.5-10: Omit dose
    • If High risk bleed consider PO VitK 1-2mg or IV 0.5-1mg and pt needs close followup within 24hrs
  • >10: Stop warfarin, VitK, repeat INR at 12-24 hrs
    • High risk patient? Consider PCC 15-30IU/kg
A somewhat simplified algorithm:

A nice concise chart brought to you by our colleagues in Wales:
Sources: Circulation, Surgical Critical Care guidelines, LITFL, CHEST