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.