Saturday, January 21, 2012

Observation For Anticoagulated Head Trauma

Coming in a future issue of Annals, the Editor's capsule summary: "Delayed intracranial hemorrhage is common after minor head injury when patients are receiving warfarin. A minimum protocol of 24-hour observation followed by repeated scanning is necessary to detect most such occurrences."

Now, this isn't a terribly management agnostic statement.  It does not specifically state this is something we need to start doing - but it rather implies that, if you don't, you'll be missing this "common" phenomenon.  It isn't an alien concept - since 2002, the European Federation of Neurological Societies has recommended admission for observation after minor head trauma - but it's certainly not the standard of care here.  So, for the Annals editors to state that observation and repeat scanning is "necessary", they must obviously have excellent evidence.

Or they have an observational case series consisting of 87 patients from Italy.

These authors present a prospective case series of all patients at their institution who were admitted for observation specifically for minor head trauma while on oral anticoagulation.  At the time of repeat CT scanning 24 hours later, the authors report five of them had new bleeding detected.  In addition, two patients who were discharged after two negative CT scans returned with symptomatic bleeding, one at two days, and one at eight days.

So, should we be observing and rescanning every anticoagulated minor head trauma patient as these authors suggest (and as they do in Europe)?  If you practice in a zero-miss litigation environment, this article and ACEP's apparent embrace of the results will hamstring your decision-making.  This data is completely inadequate to change clinical practice, and inconsistent with prior literature documenting delayed hemorrhage in only 2 of 137 patients.

Clearly, some patients will have delayed bleeding - a subset of which will be clinically significant.  However, we simply cannot expose all anticoagulated patients with minor head trauma to the harms and costs of hospitalization.  Better studies are required to prospectively determine the risk profile of patients who require further observation in a hospital setting, rather than a watchful discharge home.

"Management of Minor Head Injury in Patients Receiving Oral Anticoagulant Therapy: A Prospective Study of a 24-Hour Observation Protocol"


  1. I agree. Can you determine how they calculated their RR?

  2. Eight patients had an INR > 3. Of those, four had bleeding.
    Of the remaining 79 with INR < 3, three had bleeding.
    (4/8) / (3/79) = 13.1.
    So, after working overnight, I must be a little off with one of the numbers in there, but that should have been the RR calculation.

  3. Sometimes I think some things are best left unstudied. Now we are creating "head trauma rule out units" similar to chest pain units that are going to have even lower yield than our already low yield chest pain units.

    I don't really care about the 5 out of 87 (6%) that had a new lesion on repeat head CT- I care about the 1 out of 87 (1.1%) that needed a crani. They also say that 1 out of those 87 patients had a neurological decline during hospitalization- I assume it was the same patient that needed the crani but I can't tell after reading the results section multiple times. We should care about the patients that need an intervention- ala the PECARN head CT rule for kids. In that rule, we don't care about a little bit of blood, we care about needing clinical intervention like neurosurgery, intubation, or prolonged intubation.

    I don't care about finding intracranial blood- I care about finding intracranial blood that we have to do something about. With this disease process- we never truly know the denominator- we have no idea whether people (healthy or not, on coumadin or not) are walking around with asymptomatic intracranial hemorrhages from trivial head trauma that would be detected on head CT who would have done fine without a few milliseverts to the head.

    1.1% is just not a high enough yield to be admitting every elderly patient on coumadin with a head injury. If it was 5% or so then we can talk. There are better ways to spend our healthcare dollars, and no I'm not advocating rationing or euthanizing elderly patients- just using some common sense.

    Would a happy medium be to have the patient return to the ED in 24 hours for a repeat head CT, thus saving an admission? (Although I don't know what is more expensive- 1 ED visit and an admission or 2 ED visits). Now we probably need a larger study because the CIs are 1-11% for the 6% stat of new intracranial hemorrhage- using an online calculator, the CI for the 1.1% statistic of clinically significant hemorrhage at -1.29 and 3.29 but I'm not entirely sure I did it right. Of course this CI is not calculated in the study because it doesn't support the study's conclusion.

    Thoughts on this?

  4. Yes - clinically significant intracranial hemorrhage is much different from intracranial hemorrhage. There was a study out of Switzerland that felt it would be reasonable to discharge infants who were found to have traumatic SAH after a short period of observation - and they're probably right.

    Our healthcare system is defined by inefficient allocations of resources for risk mitigation without coming up with a reasonable alternative. One person might have clinical deterioration - therefore we must admit everyone. Is there no middle ground? A 24-hour return for CT might be reasonable - but then, likely, you're only picking up the asymptomatic hemorrhage that isn't clinically significant. Or, you can look at the two folks who returned at day 2 and day 8 with symptomatic hemorrhage - what sort of outcomes did they have? If you experience symptoms of ICH at home with proper supervision, are the outcomes noninferior to the folks who have ICH during their period of hospital observation? They aren't asking the right questions - because to do so would discount the premise of their study and reduce its likelihood of being published.

  5. Great post and comments. I am surprised this made it through peer review.


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