Ultra light hyperbaric chamber

Portable high altitude hyperbaric chambers have been around since the 80's but haven't evolved much since then, why? Most likely because of the presences of bottled oxygen on commercial expeditions and the fact they are expensive and heavy has led to them being more or less forgotten about

The principal is very simple when you ascend to high elevations the air pressure drops, what happens to your cells is like a closed bag of chips, they expand, too much too soon and they leak!, this is oedema/ AMS. The best way to reverse this is to go down or if that's not possible because of weather or you have ignored the warning signs and are now incapacitated then creating a higher-pressure atmosphere via a hyperbaric chamber can reverse these effects. The idea being once the patient has recovered, they can descend on their own steam. 

Reading stories from some high-profile climbers that had had people die with them at altitude, like Ueli Steck tried to rescue Iñaki Ochoa de Olzaon Annapurna and Greg Child tried to save Peter Thexton on broad peak to name a few. I wondered if they would still be alive if they had had something like what want to make?I aslo spoke with Tim Macartney-Snape and this is what he had to say about his experience with them.

-----

"Acute AMS is a small but real hazard for people going to high places that are slow and difficult to descend from. Constant self monitoring is essential to head off the progression of mild AMS, which almost every climber gets before it morphs into the acute phase which can rapidly occur if you do not descend or continue to go up. 

Since I gave up regular high altitude expeditions and instead took to conducting exploratory treks - up to 6500 metres, taking many fit people with little prior exposure to altitude, I’ve always taken the commercially available PAC. I’ve had cause to use it on almost every trip making a huge difference to victims being able survive to continue enjoying the trip and to my own peace of mind.

The PAC in use in West Nepal (taken by Tim)

For example we were attempting a 6,400 metre trekking peak and had established a base camp at 5400m at the head of a trackless, long, low angled, meandering valley. After a day there, one of our group began to suffer from deteriorating symptoms of AMS indicating the sensible option of immediate descent, a difficult option with night falling and a full day required to drop just 1000 metres.

Instead I put her in the chamber and she spent the next hour and a half at an equivalent altitude of about 3500 metres. After emerging her acute headache and nausea had disappeared and she was able to spend a comfortable night at base camp. She went on to climb to just over 6000 metres where the climb was abandoned due to unstable snow conditions.

Sometimes victims never fully recover but recover enough for them to be able to descend under their own steam. Apart from being potentially life saving, such a system brings enormous peace of mind. Having a lightweight option on an expedition would definitely reduce the extra stress worrying over the unpleasant spectre of deadly AMS."

------

So when I started to plan my first attempt to climb an 8000m peak I wanted to do it when there were no other expeditions around and without oxygen. The team I was going with had less experience than me at altitude and I wanted to have a means to help them if they were to get AMS. I looked around on the internet and did some research, everything seemed expensive and heavy. There was no way I was going to carry an extra 3-8kgs up a mountain or travel with on a plane with that weight. Also, the reality is if you are going to need one it will be most likely on the mountain not at basecamp (although possible) which is as far as they are usually carried .

The light weight chamber at Makalu

The Gamow bag 'ultralight' is the lightest one available but costs $2700 usd and is over 3 kgs and not possible to ship outside of the US an Australian made portable altitude chamber 'PAC' comes in at 'less than' 8kg and no price is given.

The idea of Sitting helplessly by a climbing partner and watching them die didn't have much appeal so I decided to try and make one myself, first step was to see if modern lightweight fabrics could handle to pressure, most chambers on the market are designed to with stand 2psi which isn't much in the scheme of things. So, I converted a sea to summit first aid stuff sack into a mini chamber by adding a bike valve and sealing the top with a Ziplock and roll top closure system. It worked! the fabric had no problems dealing with the pressure at all.

The next step was a full size prototype, I bought some fabrics and started making, my issues that I came up against were mostly to do with the seam sealing and roll top closure, so I bought some 210 denier TPU fabric that I could weld with an iron , the same material used on pack rafts and I tried and pinch top closure at the top ,similar to what's on top of some hydration systems. It worked but without a factory I didn't trust my welds and it seemed to unreliable to use in the mountains.

I reached out to a Canadian industrial designer that was a friend of a friend and he agreed to make me a prototype. We went back to a conventional zipper design and tape seam sealing, we made a test pillow that he put a whopping 10psi in and still only had a slow leak failure, he couldn't get it to explode so we know the fabric is more than strong enough.

In total the bag only weighs 735g and in total with pump 1.30kg! significantly lighter than anything on the market, its probably the lightest hyperbaric chamber in the world.

I think this is fairly incredible and with some more experimenting and refining its defiantly possible to have something that is under 1kg total.  For example, we still have used only off the shelf pumps and valves with minor adjustments to save weight, designing lighter versions of these components would reduce the weight further

The biggest user group for the chamber would be for small expeditions in remote areas where help and resources are a long way away. In saying that there still a reason for it to have a place on larger commercial trips ,because its light and can be used endlessly it would remove the need to carry 'spare' oxygen. Also, anyone guiding high altitude treks or climbs with clients would be able to carry it with them and have it readily available to assist a client. 

I recently lent the chamber to Ed at feeding the rat expeditions, He runs expeditions to the north side of the Karakoram and in Tibet and he's written a review and his thoughts that can be found here on his website.

https://feedingtheratexpeditions.com/2024/03/ultralight-hyperbaric-chamber

If you have and interesting high altitude expedition coming up and you would like to test the prototype on or are interested in collaborating with Matt Scholes, please contact him via email at mymatematey@hotmail.com