So maybe you can use that for a wilderness airway

We’re going to have to talk about the improvised wilderness airway. Caveat: this post is not exactly evidence based. It’s literally an anecdote. But an amazingly good and peer-reviewed anecdote at that. And there is a smattering of evidence thrown in at the end. Typical wilderness airway tool

The case report starts like this: Three firefighters were climbing as part of a team in California when they saw a man falling ~1500ft down a rocky slope. They descended to offer help, and when they got there they removed his helmet, checked ABCs, and maintained his C-spine. Neurologically he was unresponsive. Two emergency doctors with a separate climbing team arrived 15 minutes later. By this time his respirations were irregular and they noted significant facial trauma. Due to gurgling respirations, they decided to perform a cricothyrotomy.

All the physicians had for supplies were climbing equipment and a small first aid kid. They used a pocket knife to make the incision (vertical first, then horizontal), and tubing from a hydration pack as a makeshift ETT. Suture from the first aid kit was used to secure the tube. Since respirations were spontaneous, they did not perform positive pressure ventilations initually.

His pelvis was bound with a pair of pants, and extra clothes were used to prevent hypothermia. After 30 minutes though, his respirations became irregular again. Blood was noted in the tube, so the team decided to create a makeshift positive pressure bag using the rest of the hydration pack. One of the team would blow into hydration bladder to inflate it, and close it off using pliers as a valve of sorts. They would then deliver breaths by squeezing the bladder, similar to commercial products. They used this for another 30 minutes successfully.

Helicopter transport eventually was able to evacuate the man, and it turns out that a 6.5 ETT adapter fit into the makeshift tube easily. A bougie did confirm airway placement, and etCO2 readings were monitored. Unfortunately the patient went into V fib, got ROSC, then went into it again shortly after. The patient never regained pulses after that, and was pronounced dead prior to landing at the hospital.

The most important point of this case report isn’t the cool factor of Macgyvering other equipment into functional airway tools. It’s making the hard decision to perform the cric in the first place. Making that call, even in a low resource setting, is critical. Sadly this patient didn’t survive the injury, but it wasn’t due to lack of an airway. The fact that these physicians were able to also devise and then produce something that gives some form of PEEP is icing on the cake. However, it would be nice if someone took this device and measured what kind of pressures they could obtain with it.

And remember, if you’re going to perform a makeshift cricothyrotomy as your wilderness airway, make sure to use something of proper diameter. Ballpoint pens have too much resistance, but sports bottle and hydration bladder straws will work in a pinch.

Improvised Cricothyrotomy on a Mountain Using Hiking Gear
http://www.wemjournal.org/article/S1080-6032(16)30208-3/abstract

SteriPEN, convenient or worthless?


Clean water is of utmost importance, whether you’re backcountry hiking, camping, or travelling abroad. And there are many ways to disinfect water, including chemical tablets, mechanical filters, simply boiling, and ultraviolet light. And while we know that UV light from the sun works with enough contact time, does a handheld UV light work well enough to be safe?

They’ve been around since the late 90s, but decreases in size and cost have made them more popular recently. They are lighter than ceramic filters, don’t require heating and then cooling the water, and they don’t leave a funky taste in the water after use. And while you can go to SteriPENs’s website and see a bunch of articles they sponsored showing how awesome they are, it’s nice that an independent group has finally looked into their effectiveness.

One of the things the article points out is that UV light is bacteriostatic, not bacteriocidal. Their DNA is damaged, so they can’t reproduce or cause infection (probably), but the water is disinfected, not sterile. Also, while still effectively treated by UV light, viruses and spores require much higher doses to be inactivated.

They tested the function against of the SteriPEN against water bottles contaminated with Escherichia coli, Staphylococcus aureus, and the spore of Geobacillus stearothermophilus. Using 1 L bottles in 3 different styles (wide mouth reusable, narrow mouth reusable, and disposable narrow mouth bottles), they either agitated as per the instructions for the device, or let the water remain calm. For wide mouth containers, you can stir. With narrow mouth bottles, you need to plug the mouth with the pen and invert and shake. However, knowing that many people don’t do this, they also did a test by simply stirring the narrow mouth bottle as well. They also measured the spectrum emitted by the device during use.

Used correctly the SteriPEN works pretty well. Bacteria counts were reduced more than 99.99%, but spores were only reduced 99.57% on average. If you don’t agitate the water, this drops to 94.2% on average. The SteriPEN does emit its maximal intensity of UV at 254nm, which is the most efficient wavelength for bacterial DNA. And in a bottle made of glass, PET, or metal, there’s no risk of UV injury to the user, as it’s all blocked. However, in a big open-topped pot, there’s a risk of UV emission that could be hazardous to the eyes. Thankfully, the device won’t turn on if not immersed in water.

Therefore it is ok to use a SteriPEN to disinfect your water, as long as you’re doing it right. You’ve got to agitate the water, not just put it in and let it sit there. These authors also didn’t test against viruses, but the manufacturer does have data, and since this paper replicates some of their other results, it’s not unreasonable to state that it likely works against those as well.

Downsides are a few. 4 AA batteries only gives you 100 cycles and the bulb is pretty fragile, so pack extras. It doesn’t filter out toxins, and turbid water decreases efficacy, so you might night a filter anyway. This particular device has 2 settings, 90s of light for 1L containers, 48s for 0.5L ones, so you’ll need to make sure you have it set for the correct size as well. Finally, it doesn’t keep the water disinfected forever, so be aware that the water can become contaminated again and require re-treatment.

Drinking water treatment with ultraviolet light for travelers – Evaluation of a mobile lightweight system
http://www.travelmedicinejournal.com/article/S1477-8939(15)00174-X/abstract
And it’s FOAMed!