Monthly Archives: November 2010

General

Up In The Air: Tree Stand Injuries

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Deer hunting season is upon us, so it’s time for emergency departments to start seeing an increase in hunting injuries. Although you would think this would mean accidental gunshot wounds, that is not the case. The most common hunting injury in deer season is a fall from a tree stand.

Tree stands typically allow a hunter to perch 10 to 30 feet above the ground and wait for game to wander by. They are more frequently used in the South and Midwest, usually for deer hunting. A recent descriptive study by the Ohio State University Medical Center looked at hunting related injury patterns at two trauma centers.

Half of the patients with hunting-related injuries fell, and 92% of these were tree stand falls. 29% were gunshots. The authors found only 3% were related to alcohol, although this seem very low compared to our experience in Minnesota.

Most newer commercial tree stands are equipped with a safety harness. The problem is that many hunters do not use it. And don’t look for comparative statistics anytime soon. There are no national reporting standards.

The image on the left is a commercial tree stand. The image on the right is a do-it-yourself tree stand (not recommended). Remember: gravity always wins!

Commercial tree stand Do-it-yourself tree stand

General

Trauma Undertriage: Why Is It Bad?

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Trauma centers look at over- and undertriage rates as part of their performance improvement programs. Both are undesirable for a number of reasons. I’ll focus on undertriage today, why it happens and what can be done about it.

Undertriage in trauma care refers to the situation where a patient who meets criteria for a trauma activation does not get one. First, calculate your “magic number”, the number of patients who should have been trauma activations.

If you track the exact triage criteria met at your hospital, it is calculated as follows:

 Magic Number = (Number of ED trauma patients who met activation criteria
                                           but were not trauma activations)

If you don’t track the triage criteria, you can use ISS>15 as a surrogate to identify those patients who had severe enough injuries that should have triggered an activation. This is not as accurate, because you can’t know the ISS when the patient comes in, but it will do in a pinch. In that case, the magic number is:

Magic Number = (Number of ED trauma patients with ISS>15
                                           but were not trauma activations)

Your undertriage rate is then calculated as follows

                                        Magic Number
        ———————————————————–    x 100
                   Total number of trauma patients seen in ED

Undertriage is bad because patients who have serious injuries are not met by the full trauma team, and would benefit from the extra manpower and speed possible with an activation.

The most common causes for undertriage are:

  • Failure to apply activation criteria
  • Criteria are too numerous or confusing
  • Injuries or mechanism information is missed or underappreciated

Undertriage rates can range from 0% to infinity (if you never activate your trauma team). A general rule is to try to keep it below 5%.

If your overtriage rate is climbing past the 5% threshold, identify every patient who meets the ISS criterion and do a complete ED flow review as concurrently as possible. Look at their injuries/mechanism and your criteria. If the criteria are not on your activation list, consider adding them. If the criterion is there, then look at the process by which the activation gets called. Typically the ED physicians and nurses will be able to clarify the problem and help you get it solved. 

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.