Category Archives: Macgyvering

A novel prevention for acute mountain sickness

Every now and then someone thinks outside the box and causes a change in medical care. This is one of those things. I was alerted to this letter to the editor by the always excellent R&R in the Fast Lane, and when I went to the original source, I was astounded. Not many people would consider inducing pneumoperitoneum as a treatment for anything.

The letter is published almost like an abstract, and does a good job of explaining the problems that people run into when they have to go to high altitudes on short notice, such as rescuers of natural disaster victims like the one recently experienced in Nepal. And while I agree with them that there may not be time for people to go through any of the the classically used acclimation methods, I’m not sure that we should extrapolate the data that says injecting 20mL/kg of oxygen under skin can reduce the symptoms of AMS. Notwithstanding the fact that I cannot get that article to even see what they were talking about, this letter at least mentions that subcutaneous injection wouldn’t be able to hold enough oxygen. How does it hold 20mL/kg to begin with?

So of course the next logical step for a viable container is the peritoneum. They even go to great steps to mention how to create said pneumoperitoneum, and how to make sure that you don’t create too much pressure in the abdominal cavity. What they don’t explain is how there’s a place that is too remote to have oxygen tanks, but is able to use trocars to inject oxygen into the peritoneum AND be able to measure the pressure of said abdominal cavity. So, while this may in theory work, there are easier, much less invasive methods of carrying extra oxygen up the mountain. Why take it out of the bottle to begin with?

There’s a fair amount of theory about the benefits of this, including increased airway resistance, and decrease in free radicals. I don’t buy it, because you get more free radicals with hyperoxemia, which is what they’re advocating to begin with. And I’m not sure increased airway resistance would be all the beneficial either. Not to mention the obvious problem you have with expansion of gas as you decrease atmospheric pressure. I’m sure people would love the feeling of their abdomen doubling in size. So while they end with:

In summary, artificial pneumoperitoneum should be considered for AMS prevention in persons who must ascend to high altitude and begin work without rest and acclimation.

I say we shouldn’t consider this.

An artificial pneumoperitoneum created by injection of oxygen may prevent acute mountain sickness.
http://www.ncbi.nlm.nih.gov/pubmed/25910671

Necessity is the mother of tourniquet invention

A lot of wilderness medicine teaching is geared towards bringing the right tools for the circumstances, but sometimes you end up in a situation where you don’t have the best tool for the job. Thus,  quite a bit of preparing for austere environments is making improvised devices out of whatever is lying around.

This article discusses one of those macgyvered lifesaving tools. While there are many commercially available tourniquets out there, there are still times when you have to create one out of something else. As the article points out, you might simply run out of tourniquets at a mass casualty incident. When the situation arises that you have to create a tourniquet, what items should you use to make one?

The authors chose to test the band and windlass design. They mention that this was based on a paucity of non-military literature about various improvised tourniquets. The band was always cotton cloth folded into shape, and they tested 3 items common to the urban environment as windlasses. While pencils, chopsticks, and popsicle sticks might not exist in the wilderness, they’re a reasonable idea for testing. It’s not like you can ensure quality control with broken twigs.

Using a computerized above-the-knee amputation simulator, they then attempted to stop bleeding using the improvised tourniquet and one of the potential windlasses. If 1 pencil, popsicle stick, or chopstick was insufficient to stop bleeding (or broke), the test would be repeated with 2, 3, or 4 until 100% effectiveness was reached.

Granted, this study only looked at occluding arterial flow instead of venous, and had a very narrow scope of windlasses. In the end, the take-home message is as follows:

  • Popsicle sticks suck as windlasses, and you shouldn’t use them. They often broke on the first turn.
  • Pencils are better, but still pretty terrible.
  • Strangely enough, chopsticks work best of those tested.
  • 2, or better yet 3, is always better than 1 when it comes to windlasses
  • Maybe use something other than flimsy wood objects when you make an improvised windlass, such as plastic or metal
  • Use a commercial device if you can find one

Which Improvised Tourniquet Windlasses Work Well and Which Ones Won’t?
http://www.ncbi.nlm.nih.gov/pubmed/25771027