Tag Archives: INR

General

What’s The INR Of Fresh Frozen Plasma?

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So what’s the INR of FFP? Or stated another way, what’s the lowest you can correct a patient’s INR using infusions of fresh frozen plasma?

One of the mainstays of correcting coagulopathy, either from hemorrhage or due to medication like warfarin, is transfusion of FFP. Frequently, clinicians will write orders to administer FFP until a certain INR is achieved. What is a reaonable INR?

A “normal” INR is 1.0, plus or minus about 0.2, depending on your laboratory. However, two separate studies have shown that transfusion of FFP will not reliably decrease the INR below about 1.7. 

Bottom line: The answer to the question is about 1.6. If any clinician orders FFP transfusions with a goal INR below this, it probably won’t happen. And since transfusions of any product have risks, my “juice to squeeze” ratio of risk vs benefit begins to fail at an INR of 1.6. Below that point, the patient needs a normal temperature and good perfusion to drop their INR further.

References:

  • Toward rational fresh frozen plasma transfusion: the effect of plasma transfusion on coagulation test results. Am J Clin Pathol 126(1):133-139, 2006.
  • Effect of fresh frozen plasma transfusion on prothrombin time and bleeding in patients with mild coagulation abnormalities. Transfusion 46(8):1279-1285, 2006.
General

What’s The INR of Fresh Frozen Plasma?

Leave a comment

So what’s the INR of FFP? Or stated another way, what’s the lowest you can correct a patient’s INR using infusions of fresh frozen plasma?

One of the mainstays of correcting coagulopathy, either from hemorrhage or due to medication like warfarin, is transfusion of FFP. Frequently, clinicians will write orders to administer FFP until a certain INR is achieved. What is a reaonable INR?

A “normal” INR is 1.0, plus or minus about 0.2, depending on your laboratory. However, two separate studies have shown that transfusion of FFP will not reliably decrease the INR below about 1.7. 

Bottom line: The answer to the question is about 1.6. If any clinician orders FFP transfusions with a goal INR below this, it probably won’t happen. And since transfusions of any product have risks, my “juice to squeeze” ratio of risk vs benefit begins to fail at an INR of 1.6. Below that point, the patient needs a normal temperature and good perfusion to drop their INR further.

References:

  • Toward rational fresh frozen plasma transfusion: the effect of plasma transfusion on coagulation test results. Am J Clin Pathol 126(1):133-139, 2006.
  • Effect of fresh frozen plasma transfusion on prothrombin time and bleeding in patients with mild coagulation abnormalities. Transfusion 46(8):1279-1285, 2006.
General

What INR is Safe for Ventriculostomy Placement?

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Intracranial pressure monitoring has been shown to benefit patients with severe brain injuries. Neurosurgeons are reluctant to place these invasive monitors in patients with abnormal coagulation studies, and many times expect the coags to be completely normal. Is this reasonable? Brain injury itself can raise the INR. When is it safe to place one of these monitors?

Researchers at the University of Alabama – Birmingham performed a retrospective review of their experience with 71 patients who underwent ventriculostomy with a range of INR values. None of these patients were on warfarin. Eighty one ventriculostomies were performed after an average of 1.5 attempts. They looked at the incidence of new hemorrhage seen on CT after placement. They found:

  • Patients with an INR < 1.2 had a 9% incidence
  • Patients with an INR from 1.2 to 1.4 had a 4 % incidence
  • Patients with an INR > 1.4 had an 8% incidence

If the neurosurgeon, is unwilling to place the ventriculostomy until the INR is normalized, there may be several additional sources of morbidity:

  • Additional brain injury that is not known and treated due to the lack of an ICP monitor
  • Potential infectious and other complications (transfusion reaction, TRALI) from plasma administration
  • Cost for the transfusion products

The patients who did have hemorrhage generally had a small focal area. The one significant hemorrhage occurred in a patient on clopidogrel (Plavix). 

Bottom line: The numbers are small, and this is retrospective work. Based on their study, the authors are comfortable placing ventriculostomies in patients not on Coumadin with an INR up to 1.6 without plasma administration beforehand. Colpidogrel should be considered as a separate risk factor.

Reference: The relationship between INR and development of hemorrhage with placement of ventriculostomy. Bauer DF et al. J Trauma, in Press Aug 27, 2010.