Monthly Archives: April 2015

Use hematoma blocks for wilderness anesthesia

You’re on a simple hiking expedition and suddenly a member of the group takes a wrong step on the trail and collapses in pain. You examine them carefully and discover a gnarly ankle fracture-dislocation. It’s a bit of a walk back to camp, and you’re worried about the foot’s neurovascular status during the return. What do you do?

Well, if you were in the ED, you’d likely hook the patient up to every single monitor in the room, get 7 providers in the room, fill out the mandatory checklist, and perform procedural sedation. However, you’re out in the woods, and the pine trees don’t have etCO2 monitors built into them. You could give a hefty dose of pain medicine and try to yank the foot back into place, but prior experiences trying to reduce limbs without adequate analgesia or sedation lead you to decline that option. Unfortunately, now you’re out of options.

Or so you thought. It turns out that there’s a surprisingly effective option promoted by our orthopedic colleagues (or at least one of them). Enter the intra-articular hematoma block of the ankle. You may have done intra-articular anesthesia with a dislocated shoulder before, and you’ve probably done hematoma blocks for wrist fractures. It works for those, so use it here as well. The author of the paper is even nice enough to give a figure demonstrating exactly where one should put the block, assuming the anatomic landmarks aren’t obliterated by the fracture-dislocation.

From the original article

Insert the needle in a lateral and cephalad direction. If you hit the talus, pull out and aim higher. Aspirate blood, and inject your lidocaine. Done correctly, the patient will have complete anesthesia to the joint, allowing you to perform a successful reduction. The article has a nice technique for accomplishing reduction if your usual brute force doesn’t work. It’s similar to the finger trap technique taught to reduce a Colles’. Basically, you place the leg into tubular fabric and suspend the affected extremity in the air. Gravity and rotational forces then gradually pull the ankle joint back into place. If you don’t happen to pack stockinette in your first aid kit, you can use socks, thermal underwear, long shirt-sleeves, or even tight-fitting pants instead.

Just make sure and immobilize the joint afterwards, and remind the patient that just because their ankle is numb doesn’t mean it’s a good idea to stand on it. And while this article only discusses ankle injuries, other fractures are amenable to hematoma blocks as well. Yet another arrow to add to your wilderness medicine quiver.

Field Management of Displaced Ankle Fractures:Techniques for Successful Reduction
http://www.ncbi.nlm.nih.gov/pubmed/19364168

Femoral traction splints, helpful or not?

It’s been awhile since the FOAM twitter community got together and discussed the utility of femoral traction splints. Thus, forgive me for not remembering all the finer details of everyone’s points of view. The gist of that discussion was similar to many other twitter-based medical discussion. Many anecdotal accounts of benefits of an intervention (in this case, traction splints), vs the utter lack of data showing benefit. Knowing that absence of data does not equal absence of benefit, we all left likely doing the same thing we were doing before. And that discussion was mostly directed at commercial devices used in inter-facility transport or in-hospital use.

In wilderness medicine, the situation is even worse. Poor or completely nonexistent data, and even fewer premanufactured devices are available. Therefore, many “traction” splints are make-shift devices that are macgyvered out of available materials. After all, make-shift devices are the essence of austere medicine.

But do we need to be doing them at all, and more importantly, should we be teaching the next generation of wilderness medical professionals to do it ad infinitum? Let’s face it, the devices we concoct out of ski poles, webbing, carabiners, and the like, often aren’t very good at providing traction to begin with. They simply aren’t robust enough compared to commercial products. Not only that, but the usually involve some poor soul being left without a shirt, poles, a jacket, and maybe their backpack. If there’s real benefit to doing it, that’s a reasonable sacrifice. But if there isn’t, is it time to stop?

This article investigated the use of femoral traction splints by Mountain Rescue England and Wales, as well as did a literature review to see if there is any definitive data for or against the use of traction splints. The authors also surveyed rescue teams to assess their use and opinions of traction splints.

They found that suspected femur fractures were fairly uncommon in their cohort, occurring at a rate of less than 10 per year. This likely overestimates actual fractures by a decent margin as well. Of these, only 13% were treated with traction splints, 17% with non-traction splints, and a whopping 70%(!) without any splinting at all. This data flies in the face of what was reported by the responding rescuers. Fully 68% reported that they used a traction splint for every suspected femur fracture, and the other 32% said they selectively used them. Generally they felt the devices to be useful and not problematic in the survey as well. Then why aren’t they using them? This isn’t answered by this survey, but I bet a few medical directors out there would like to know why their medics are saying one thing, and doing another.

What did the literature say about traction splinting? Of the 141 they found using Boolean operators, only 5 were ultimately included in the review. The rest were historical, single case reports, too low level of evidence, or not pertaining to the issue at hand. And of those 5 (see references below), all were level of evidence 4. Shockingly, there aren’t a lot of double blinded RCTs on this topic.

Of those articles, they also found that splints were often applied to patients with contraindications, are rarely used, take up space, and don’t have much evidence for their benefit. Specifically, the often theorized benefits of pain reduction, bleeding, and nerve injury are not shown in any recent literature. There is a book from 1919 (Gray, H. The Early Treatment of War Wounds. H Frowde, Hodder and Stoughton, London; 1919) that argues a reduction of death from 80% to 15% for femoral gunshot injuries, but this can’t be used realistically today as evidence.There is a teaser at the end of the article though. Susanne Spano at UCSF-Fresno presented a poster at SAEM with some good data that showed no statistical difference in mortality or complications of actual femur fractures treated with either traction splinting or no traction splinting.

The main problem in prehospital or wilderness care is that the person with the femur fracture also needs extraction. Traction splints interfere with many litters, are by design only useable for 1 type of injury, and require a significant amount of highly specific training. In the end, I’m not saying that traction splinting isn’t without benefits. In the pre-hospital or austere setting, these benefits are much smaller and have a higher risk associated as well. And certainly I don’t advocate not immobilizing the limb, as this clearly has benefit. But creating a make-shift splint needs to stop being taught as the best or only way to treat femur injuries. And simple splinting should be used until we have clear data showing a benefit to traction splinting.

Femoral Traction Splints in Mountain Rescue Prehospital Care: To Use or Not to Use? That Is the Question
http://www.wemjournal.org/article/S1080-6032(15)00075-7/abstract

Referenced Articles

Agrawal, Y., Karwa, J., Shah, N., and Clayson, A. Traction splint: to use or not to use. J Perioper Pract. 2009; 19: 295–298
Wood, S.P., Vrahas, M., and Wedel, S.K. Femur fracture immobilization with traction splints in multisystem trauma patients. Prehosp Emerg Care. 2003; 7: 241–243
Abarbanell, N.R. Prehospital midthigh trauma and traction splint use: recommendations for treatment protocols. Am J Emerg Med. 2001; 19: 137–140
Bledsoe, B. and Barnes, D. Traction splints: an EMS relic?. JEMS. 2004; 29: 64–69
Ellerton, J., Tomazin, I., Brugger, H., and Paal, P. International Commission for Mountain Emergency Medicine. Immobilization and splinting in mountain rescue. High Alt Med Biol. 2009; 10: 337–342

If you don’t use it, you lose it

It’s a common perception that “book knowledge” does not give on the ability to perform skills. People can answer the questions correctly on a test, but not do the right thing in a real life scenario. For the practical component to be there, you must have some degree of hands-on education and experience. Most (if not all) wilderness medicine courses have a mixture of both lecture and practical stations because of this need. But how long does that knowledge stay with the learner?

Honestly, nobody seems to know. Skills degrade when they aren’t used, but does it happen in one day, a week, a month, or a year? To see how well students retained the information they received from wilderness first aid courses, the authors of this study took participants and measured their baseline (post course) knowledge, and then randomized them to be followed up at 4, 8, or 12 months for retesting. To measure knowledge, they were given a 25 question multiple choice exam. It doesn’t mention if the followup test was identical to the original, but lets hope it isn’t. The participants were also asked to rate their own self efficacy based on an 11 point Likert scale that ranged from “cannot perform this at all” to “can perform this with high certainty”. The designers of that scale must have been fans of Spinal Tap.

At their followup testing, the study participants were again given the exam and asked to rate themselves. Then, first aid skill was measured by observing them do 8 specific skills as part of a clinical scenario. Unfortunately, this skill measurement was not performed at baseline, so absolute decline in practical application cannot be determined. However, based on their data (not shown in the article), they determined that skills declined as the time delta widened. It’s a bit confounding though, as the 8 month group did worse than the 12 month group in some skills. Their exam scores also decreased as time went on, but not to the same degree.

Thus, ability to do well on repeat written examination does not magically give one the ability to manage an actual clinical scenario (but those people probably do better than someone who did poorly on the written exam). And, as it turns out, how well you think you’re going to do doesn’t mean you’ll have the practical skills needed either. Like tying knots, the more regularly you practice them, the better you’ll get. And the knot you should use in a rescue situation is the one you can tie the best, not necessarily the ideal one taught in a class. In that regard, it’s important to note that they specifically excluded anybody who did have further training in wilderness medicine since the first course.

The problem is this: How often do you have to refresh those skills? This article doesn’t answer that question, but it certainly points out that those practical skills erode to a higher degree in between training than test scores do.  Some of this is common sense. It’s easy to do well on a multiple guess test if you’ve had some passing familiarity with the material, as the answers often refresh your memory. Doing the same in a clinical scenario is much more difficult if you haven’t practiced it since the last course. None of this is necessarily groundbreaking, as other studies have shown similar time dependent degradation. Thus, anything that you need to be facile with, needs to be done more regularly than every two years.

An examination of wilderness first aid knowledge, self-efficacy, and skill retention.
http://www.ncbi.nlm.nih.gov/pubmed/22857870

How you wash your utensils matters

When you’re out in the wild for extended periods of time, you’re always reminded of the need to eat. Some get around this by only carrying pre-prepared foods. Others decide to cook, which inevitably leads to dirty dishes. Even if you make the grave sin of using disposable dishes and silverware, you still have to clean the larger containers you prepare the food in. And when somewhere between 1/3 and 3/4 of hikers end up with diarrhea, cleaning of these dishes is clearly important. 

If you’re car camping and have running water, you can go ahead and move on to another blog post. Fresh running potable water makes this job easy. But for those times when it isn’t available, you need to clean your utensils somehow. Many of us have been taught the 3 bowl system seen above, where you wash in the first bowl, rinse in the second, and disinfect in the third. It has similarities to the 3 sink systems many restaurants use. But does this mean it’s best?

To find out, a group of authors decided to test 18(!) different 3 bowl systems to see which actually reduced bacterial loads the most. They used porridge contaminated with E. coli, a practice I can’t recommend when camping. (They describe the contamination in excruciating detail, using 232 words). The authors trimmed the systems to 10 after finding 8 of them “wholly inadequate.” Describing each of the systems is needlessly complex, so here’s Table 1 from the article. Table 1

This doesn’t entirely explain their methods though. When they wrote “established”, they meant washing until visibly clean in first bowl, then using 2 and 3 just for rinsing and sanitizing, as it were. “Alternative” meant removing all easy food residue in bowl 1, then getting them visibly clean in bowl 2, and rinsing in bowl 3.

Their results weren’t entirely surprising. First they note that grease is only removed with detergent. Second, while systems D, F, G, and J were best for bacterial loads, E through I were easiest to use because you could see what you were washing easier in the cleaner bowl 2, and D-I where the ones that didn’t leave a disinfectant smell on the dishes when done. Putting this all together, the winner was system G in using the least bleach while still reducing coliform counts below measurable levels.

Of note, systems B and C are often what is used and taught for wilderness trips. This may be due to a real or perceived need to decontaminate the rinsing water, but the authors recommend using potable water for bowl 3. Otherwise you are left with a distinct disinfectant residue on your dishes that can be tasted at your next meal. More importantly, due to reduced contact time with the disinfectant (dunking takes less time than cleaning), they had higher coliform counts as well.

So there you have it. You can use the 3 bowl system, but not the way it’s been taught historically. You should have water and detergent in the first bowl, cleaning them mostly. Then continue cleaning until visibly clean in a second bowl of water with 10mL of bleach in it (5L:10mL water:bleach). Finally, rinse in potable water. In severely water restricted circumstances,  this system gives you the added benefit of still working when you remove the 3rd bowl, except for that disinfectant taste again. The authors do note that if an outbreak of diarrhea occurs at your campsite, consider increasing the bleach content of bowl 2 to 100mL.

Laboratory evaluation of the 3-bowl system used for washing-up eating utensils in the field.
http://www.ncbi.nlm.nih.gov/pubmed/16805145