High Altitude Indoctrination

Recently I was able to take part in the high-altitude indoctrination course in Vancouver, British Columbia, at Simon Fraser University. Until then, my connection with hypoxia was limited to academic readings, YouTube videos, and the occasional testimonial from those who had completed high-altitude training, such as those in my military circles, or those keen enough to pursue civilian training. Beyond that, I may have had an encounter with the euphoria of hypoxia years ago, but who is to know now?

Upon arriving, I was excited to pass the lab of SFUs Aerospace Physiology Laboratory, the door zapped with Canadian Space Agency, NASA-Johnson Space Centre, an STS-128 mission and space medicine patches, where experiments aboard the International Space Station were, and are, being monitored, specifically those relating to the cardio-respiratory changes in microgravity, as well as aging in the 1G environment of Earth – topics I had covered in my graduate classes on aerospace physiology and life-support systems for my space operations specialization! So, there was a feeling of excitement, no doubt, as I knocked on the door to the Environmental Medicine Physiology Unit to connect my learning to something tangible!

Once settled in, I met the group – two recreational pilots and divers, as well as an airline pilot, and of course me – a simple air traffic controller, pilot, and student (more on this simplicity later when I learn about green and red…). The morning consisted of significant insights in lecture format discussing physiology and hypoxia, as well as decompression sickness, and some familiarization with the equipment we would be utilizing. To learn that the chamber was not only hypobaric, but hyperbaric, working with divers, was very intriguing, and the maze of tubes, gauges, valves and handles made this professional development seem a little more intense than I had planned. After all, knowledge is power, but ignorance is bliss, right? Well, in this case, I sided with knowledge being power and a type of inoculation against stress. Sure, knowing what this machine did and how it did it was not fundamental to my experience – I would become hypoxic either way. But, understanding the system was crucial to my experience, and it qualified me beyond the baseline to speak on this system. Much like pilot training, we often learn things to a deeper level than practical on a day-to-day basis. 

After a brief lunch – somewhat timid of what I would put in my stomach thanks to physics and gas laws, concluding that what goes in must come out – we returned to the unit, and changed into scrubs, and were introduced to our chamber attendant, a Canadian Coast Guard diver, and we began a 30-minute pure oxygen breathe, meant to clear our bloodstream of nitrogen. During this time, we sat at a table, each of us working on an iPad through a series of cognitive exercises. I can’t lie and say that I felt like the smartest guy there – quite the opposite. Perhaps the smartest dumb guy at most (dumbest smart guy, maybe?), as I was talked through reading the word “GREEN” or “RED” which was colored either green or red, and having to choose an effective “TRUE” or “FALSE” statement. Let’s just say I moved on to the flight simulator game – I swear, the logic was not making sense!

Into the Chamber

After 30-minutes, we disconnected and made the trip into the chamber, one-by-one, and we were placed on oxygen inside of the chamber. Now, this chamber is not what I would call cozy by any stretch with its metal tubes and edges, thin seating mattresses, and dim lights. At 6’ tall, I was unable to stand fully upright, and a chain through the middle of the chamber appearing to harmlessly guide your way is the actuator for the fire suppression system. Touching this chain was covered extensively in the briefing entitled “Do not touch the chain for the fire suppression system, Nick”.

A few minutes later, clipboards and iPads in hand, the sounds of all six of us – four students, one attendant, and a lab employee – inhaling and exhaling into our oxygen masks was very apparent as we climbed to a simulated altitude of 5,000’ ASL before quickly descending to sea level, to check our ear’s ability to clear. With all of us giving the thumbs up, a climb to FL250 began! It’s a strange sensation, really. Bizarre grumbles in your stomach that quickly pass, and the sounds around you becoming distant and tin-like. Sometime later, probably 20 minutes or so, and we had arrived!

It was then that my side of the chamber was instructed to remove our oxygen masks for a rapid onset of hypoxia exercise. I reached up to my mask and pulled it over my head and within three breaths I knew something was very different. It’s challenging to describe, but most likened to that feeling when you have been consuming alcohol – particularly that one drink that you debated not having, but did anyway, and a while later that drink is the one you rationalize is blurring and dulling your senses. The air felt empty and featureless – I would inhale through my mouth and the usual cool and drying sensation just wasn’t there, nor was the feeling that I could take in a deep refreshing breath.

The chamber attendant directed us to begin some tests, every minute for five minutes monitoring our heart rate and oxygen saturation, with our partners across from us writing down our vital signs, watching for signs that we should be put back onto oxygen. I, however, stared at a page of b’s, p’s, and d’s, perhaps even a q, and searched for the b’s endlessly, before turning my attention to the iPad where, finally – in a hypoxic state – I managed to triumph over this green and red situation!

Physiologically, interesting things were happening to me, though. I had a momentary sense of concern for myself as I became very self-aware that something was not right – not quite a panicked feeling, but a kind of compulsion to reach down and put my mask on. But I was here for the experience, and I was able to fight off that feeling. However, when that passed, the most noteworthy feeling was a hot flash that covered my entire body, head to toe! Wearing only scrubs and socks with airplanes on them, the feeling of sweating all over was somewhat unexpected, and there was an associated increase in my heart rate as my oxygen saturation decreased to below 90%.

Still looking for the b’s, I remember a very slow count down through the 5-minute exercise marked every sixty seconds by a vital sign check. I was ok, but I felt like I was done – no sense of excitement or euphoria for me, just a sensation that I had come, seen and was ready to be done. Then, at the conclusion of the exercise, I reached down and placed my mask on my face, and mid-way through the first breath, the level of clarity I felt was incredible! Like fatigue, you do not quite understand how impaired you are until you are well-rested – in this case, I did not realize how far gone I was until I was back on oxygen!

Change Up

Then it was the other side’s turn, and this proved to be much more dynamic. A few moments into my partner’s session, they worked through the written tests making a connect the dots exercise out of a word-matching exercise (not unlike the red and green…), and that is when another student down from us began to effectively gaze at the floor with his oxygen saturation rapidly and unexpectedly falling below 60%. With oxygen being placed back on him twice, bringing him instantly to the high 90s, the five minutes concluded, and we all agreed that the sensation of hot flashes and discomfort was quite different than we had anticipated. Hypoxia was, indeed, a thing…, but perhaps not quite as advertised.

From here we took a slow descent to 18,000’ where we stayed off oxygen for nearly 30 minutes. Now, here is where I found the most intriguing and insidious results. First, I felt nothing unusual – breaths were more invigorating than at FL250, and the hot flashes were no longer an issue. We sat about, flying on the iPads, discussing the FL250 experience, (I once again battled evil with green versus red…) and that is when we were directed to look at a color chart – four rows of colors, with a dozen or so cells in each row of varying hues of the respective color. At first, it felt like looking at a few shades of green, orange, red, and yellow, but as we donned our oxygen masks, more brilliant shades of teal, mango and pink all began to reveal themselves! The lesson here was apparent – we were hypoxic and largely thought we were just fine.

At the conclusion of the hour-and-a-half exercise, the chamber opened, and we stepped outside where we were greeted by a physician and a medic, as well as the program director, and we began discussing our experiences and checking to ensure that we came out in the same shape we went in!

A quick medical check, including our vital signs, and we left an hour or so later. As for my personal feelings after, I experienced a brief period of heightened heart rate related to the increased cardiac output as a result of decreased oxygen in the blood – otherwise a normal response to an abnormal condition. Wearing a wristband for the following day that connected us to the Hyperbaric unit, with a phone number to be called if we were in distress, we were done and physiologically fine!

I returned to residence that evening, had a nice dinner, felt great – excited that I had experienced something new not only about aviation and aerospace medicine from a professional and academic perspective, but I had found a personal limitation that I could use to keep me and my family and friends safe while flying. Respecting these personal limitations comes out of an understanding of what your personal annunciator panel shows you – these are all symptoms that are master caution alarms that we must identify for ourselves if we want to become gurus of the most complex system we operate, our own bodies!

Give it a Try

Throughout pilot training and beyond, I would encourage everyone to seek out a controlled understanding of your body’s caution and warning system and find a high-altitude indoctrination program that is accessible for you. The fact of the matter remains that a series of general aviation accidents occur each year around the world which are left largely unresolved, and there exists no definitive rationale to exclude hypoxia as a contributing factor. As such, we must conclude that hypoxia is a more prominent contributing factor to GA mishaps, and we must arm ourselves with the knowledge and insights to prevent this layer to Reason’s Model.

I never did find all the b’s, and I still cannot figure out the greens and the reds, though – my sense is that hypoxia is not my issue there…

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