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Thread: Hypoxia

  1. #1
    Death Before Discomfort nated1971 has a spectacular aura about nated1971 has a spectacular aura about nated1971 has a spectacular aura about nated1971 has a spectacular aura about nated1971 has a spectacular aura about nated1971 has a spectacular aura about nated1971's Avatar
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    JM Hammerhead

    Hypoxia

    Not sure if this is the right place for this, but seemed a good place to start and mods can move it at their leisure.

    I had my 5 year HALO recert today and one of the requirements, other than the finger, is to go to an altitude chamber and experience Hypoxia. As my initial chamber ride was 5 years ago, and I wasn't diving a rebreather at the time, I didn't pay a lot of mind to all the symptoms. Now it seemed more relevant

    The "protocol" was to pre breathe 100% O2 for 30 minutes, take us up to 8,000' unmask and make a very rapid ascent to 25,000 feet, I believe the PO2 at that height is about .109ATA. It took about 3 minutes for noticeable symptoms, with the first one, for me, being uncomfortable dizziness and shortness of breath. Others felt euphoria and headaches. Once we finished there, we went back on 02 and I felt better almost immediately. We then dropped to 18,000', back off the mask and looked at a rainbow chart for color vision wash out. Surprisingly, green and blue were the first to go, then all the others began to dull. We did this for 5 minutes. We then went back on 02 and it was neat to watch the vibrance return to the yellow, orange and red lines.

    I know we talk about CO2 hits a lot, but knowing what Hypoxia feels like, was worth to 2 hour drive at 4 in the morning. The jump pay doesn't hurt either.

    Has anyone else experienced Hypoxia and what were your symptoms.

    V/R
    Nate

  2. #2
    RBW Member Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy's Avatar
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    Re: Hypoxia

    Prior to a supervised escape from a "caught in fishing nets" situation I doffed the unit on the floor of the swimming pool to get a scrubber from my box (in order to see where it leaked)
    I did close the O2 valve to save O2 and when done testing I donned the unit, nose vented some gas (the leaky valve had leaked a few litres in there as per normal) then squirted some O2 in (or at least pressed the button) and checked ppO2. All Ok (for now) Note that there is no re-opening of the O2 valve in this story...
    Then wrestling the fishing nets at the point of freeing myself things happened quickly.

    I THINK I remember... (memory might have been affected as well???)
    -B/W vision
    -Tunnel vision
    -Panic

    On checking pPO2 it indicated .08
    Last edited by Dutchy; 2nd September 2009 at 20:28.

  3. #3
    RBW Member Padipro has a spectacular aura about Padipro has a spectacular aura about Padipro has a spectacular aura about Padipro has a spectacular aura about Padipro has a spectacular aura about Padipro has a spectacular aura about Padipro's Avatar
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    Megalodon

    Re: Hypoxia

    I was on flying status years ago in the Air Force and was required to visit the chamber for certification. I wish I had known then what I know now, I would have paid closed attention to symptoms.

    I was told before the chamber ride to volunteer to be the first for everything (The only time in the military I ever volunteered for anything) so when the Instructor asked who wanted to experience high altitude Hypoxia I raised my hand. Unfortunately I wasn't fast enough to get the number one spot at 35,000 feet but I was lucky enough to get the second spot at 30,000. WOW, what a feeling! I remember they gave me one of those childrens toys where you have put the shaped pieces in the correct holes in a plastic ball. I was able to get all the pieces in the correct holes in under one minute but was feeling pretty happy by then. As the Instructor was emptying the pieces from the ball to give me another go at it I remember my vision narrowing to the point I could only see a small area directly in front of me and mostly in black and white. By the time he had dumped all the pieces out of the ball and gave it back to me I guess I was looking pretty bad because I remember him telling me to put my mask back on. I could hear him telling me this but I wasn't responding. I just sat there staring at the ball and the pieces in my lap. I knew what I was supposed to do but my brain just wasn't processing the information and I wasn't moving. He had to tell me at least 3 to 4 times before my mind was finally able to process everything and make my body move. I was able to press my mask to my face and after only one breath I was concious enough to hit the 100% switch. After that second breath with the added O2 it was like comming back from the dead. The whole room suddenly appeared, the colors were back, I could hear the Instructor asking me if I was OK and the other students laughing and I was able to respond immediately. If it had taken another few seconds for me to get my mask on I don't think I would have been able to do it and the entire thing lasted less then 2 minutes. I don't remember feeling out of breath or any panic in fact it was just the opposite, it was almost like being narked for me. I told the Instructor after it was all over if they could bottle and sell the feeling I had they'd make a fortune. I felt calm but totaly detached from what was going on around me. I could hear the voices of the people around me but could not really process what they were saying or even if they were talking to me. Damn scary stuff now that I think back on it but at the time I was just a dumb kid that didn't know any better.

    Oh and those color pie charts they give you. We did it at 18,000 feet and you would actually see people jump back when they put their masks on and the colors seemed to literally jump out at you.

    On a side note I did end up with pulmonary oxygen toxicity from prebreathing O2 for so many hours that week. I had this dry hacking cough but no other symptoms like a runny nose or congestion to explain it. I had no idea what it was at the time and only figured it out years later when I started learning about O2 toxicity in diving classes. I remember at first the Flight Surgeon was thinking it might be DCS and actually talked about putting me the chamber for a ride but after consulting with some other Doc's just told me go home and relax that it would clear up on it's own.

    I wish I had the chance to do it all again now that I'm diving a CCR.
    Last edited by Padipro; 5th September 2009 at 16:51.

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    Megalodon

    Re: Hypoxia

    Great video, I hadn't seen that one before. That's the exact toy I was referring to only I started placing the pieces in the holes as soon as I came off the mask so I had a little advantage, and my son had one at the time so I was able to practice with it in the days leading up to the ride. I guess I did cheat a bit but I was able to get them all in the ball the first time.

    I agree that if you're looking for a humane way to end someones life Hypoxia is the way to go. It's painless and you really don't know what's happening or care for that matter.

  6. #6
    RBW Member Peter M is an unknown quantity at this point Peter M's Avatar
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    Re: Hypoxia

    Quote Originally Posted by divetheworld  View Original Post
    This is a must watch ! part 4

  7. #7
    Dept. of Redundancy Dept. Celia_E has a spectacular aura about Celia_E has a spectacular aura about Celia_E has a spectacular aura about Celia_E has a spectacular aura about Celia_E has a spectacular aura about Celia_E has a spectacular aura about Celia_E's Avatar
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    Megalodon

    Re: Hypoxia

    Was on flight status a bunch of years ago....

    while in the chamber...

    When the time to do the rapid depressurization, everything was pretty cool for a while, then the colors went away and the tunnel vision began, very weird. I thought I was writing my name rather well on the paper they gave us at the time... (turns out that I was just making squiggly lines). After I thought it was enough, I put the mask back on and was rewarded by a widening of vision and the colors returning, no issues.

    On a side note, one of my fellow aviators decided that he was going to be the record holder for not putting his mask back on and he became at first confused and then belligerent to the point where it took the tender and another guy to restrain him and replace his mask. After he took a good breath he calmed down and was slightly embarrased...

    Interesting experience, then on, it has been an interesting time all along...



    Dive safe,

    Celia

  8. #8
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    EDO04 Ray

    Re: Hypoxia

    In order to change with this rather funny experiment, mine have been a short and scarry one..in the water.
    In short I went down on my rig to test the sensor before real dive thinking being on pure o2 but a very hypoxic heliox was accidently feeding the loop.
    Had first the uncomfortable feeling like a mild CO2 hit, reaching 6m Ive been unable to read correctly my O2 display ( unable to understand what I read ) so went slowly up then a blank..... then experimented breathing water being on my back because of the weight of the rig and drowning again because of it.
    Fortunatly I reached the surface after the black out,turned on my back durin it so fresh air woke me up and.. was not alone on this one...not sure that I could save my ass if alone.
    Been very very lucky on this one

    IMHO, underwater you can imagine to deal with a CO2 hit at the very beginning but not with an hypoxic situation that started to affect your brain
    Last edited by Marc T; 15th September 2009 at 16:14.

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