A 58 y/o female on warfarin for atrial fibrillation presents after tripping and hitting her head into the kitchen cabinet. She complains of a headache. Neurological exam is non-focal, vital signs are normal, but her headache is severe. You order a CT scan, and consider reversal of anticoagulation.
1. How long does vitamin K take to work? What is the difference between oral, subcutaneous and IV?
Vitamin K begins to work in 4-6 hours (therapeutic effect is slightly slower with oral vitamin K, and unreliable effects are noted with subcutaneous vitamin K (never use subcutaneous form)). Both routes (IV and Oral) take 12-24 hours to have a significant clinical effect. It is not the main stay for intracranial hemorrhage (although it is always given in conjunction with other reversal agents).
2. Should you order FFP or Cryoprecipitate?
FFP is separated from a single – donor whole blood, and usually frozen (it can be stored for up to 1 year). It has all the plasma coagulation factors (no platelets). It must be ABO compatible, but is not cross-matched. You will need approximately 4-6 units (equivalent of 10-15 cc/kg) infused to reverse the coagulopathy (assuming patient is not over-anticoagulated).
Cryoprecipitate is a poor source of vitamin K-dependant factors. Cryoprecipitate is only a portion of the plasma-rich clotting factors found in FFP. Cryoprecipitate is removed from plasma by freezing and then slowly thawing the plasma. In the past, it has been used to prevent or control bleeding in those with hemophilia and von-Willebrand syndromes.
3. What are the other options to reverse this coagulopathy?
At our hospital, we have a ‘head injury and warfarin’ protocol. We always have 2 units of FFP thawed to give to patients suspected of having an intracranial bleed. However, recent studies have suggested that Prothrombin complex concentrate (PCC) may be even better than FFP. PCC can provide reversal of effects in 1 hour. PCC is a direct replacement of vitamin K-dependent coagulation factors. Most ED’s do not stock this currently, but in the future, this may be available.
Huttner HB, Schellinger PD, Hartmann M, et al. Hematomoa growth and outcome in treated neurocritical care patients with intracerebral hemorrhage related to oral anticoagulant therapy: Comparison of acute treatment strategies using Vitamin K, FFP, and Pro-thrombin-complex concentrates. Stroke 2006 Jun;37(6):1465-70.