Cave diver pulled to surface barely alive - Eagle's Nest

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Originally Posted by jammer

So does that mean you can breath 100% helium on a dive less than 500ft? I am not a tech. diver so I do not know. If so why add 02 to the mix?

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Sure, you can breathe 100% helium....for about 2-3 minutes before you pass out, then die shortly thereafter due to the fact that there's no oxygen in it.

What jpdiver was getting at is that "too much" helium can't hurt you shallower than a certain depth(generally seen as 400-600fsw, depending on the person and type of mix they're using).....it's the too little oxygen part that will hurt you. For instance....at Eagles Nest, I normally dive a mix of 13% oxygen, 50-60% helium. If you breathe 13% oxygen at the surface for an extended period of time, most people(at least those that live at sea level, or below 6,000ft or so) will start to get light headed, and some may pass out, because the PO2 is only .13. Go to 33', and the PO2 is .26....more than enough to sustain life regardless of level of activity.

When you get deeper than about 400-600fsw, with a very high helium content in the gas, something known as High Pressure Nervous Syndrome(HPNS) begins to occur. It starts out with "the shakes", and gets worse from there. Do a google search for it...you'll find plenty of info...or you can learn it if/when you do trimix training.

Mike

Well we could discuss this till we're all blue in the face, but right now I think all there needs to be is prayers and support for Judi and Rudy.

Hang in there Judi....we're all praying for ya.

CaveDivingCop:

You're wasting your time. The debates and assumptions will continue. :roll:

By the way, I took an early retirement 2 years ago after spending 33-1/2 years on the streets, dealing with some of the scum of the Earth. Now I have more time for cave diving, and my blood pressure is down. :D

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Originally Posted by MikeH

Sure, you can breathe 100% helium....for about 2-3 minutes before you pass out, then die shortly thereafter due to the fact that there's no oxygen in it.

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I think it would be quicker then that. While you could hold your breath with a lung full of air for 2-3 minutes and survive for a while on the oxygen saturating your tissues breathing pure Helium would lead to a much more rapid and painless unconsciousness - likely even without warning.

Depending on your breathing tidal volume and residual air in your lungs each breath of Helium would displace more oxygen from the lungs (20% to 10% to 5% etc) in addition to metabolic consumption of the same. Unlike holding your breath though you'd also continue to remove CO2 so there would be no feeling of building "need to breath" because the body senses CO2 buildup in the blood to control breathing rate - not oxygen levels. A single deep breath and exhalation cycle could be as much as 90% efficient in purging O2 from the lungs going from ~20% to ~2% in one breath followed by almost immediate unconsciousness).

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Originally Posted by http://yarchive.net/space/science/man_in_vacuum.html

The best Earthly comparison is what happens to people who walk into a room containing a pure-nitrogen atmosphere. The analogy is fairly good; to a first approximation, when there's no oxygen present, it doesn't matter whether something else is there or not. Such accidents happen occasionally in industry. (In fact, one happened at the Ariane 5 launch site a few months back.) Sudden loss of consciousness occurs within 10-15s, and death follows quickly. Stringent precautions have to be taken to prevent such accidents, because survival is rare -- you get no warning that you're about to keel over, and rescuers must understand the situation immediately and act very quickly.

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http://cavediver.net/phpbb2/viewtopic.php?p=7843#7843

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Originally Posted by CaptainSpeleo

By the way, I took an early retirement 2 years ago after spending 33-1/2 years on the streets, dealing with some of the scum of the Earth. Now I have more time for cave diving, and my blood pressure is down. :D

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I hear ya there....I work crime scenes now....so less stress....about 9 more to go to make my 30....maybe we won't have to wait that long before we can get some dives in together and we'll trade war stories during surface deco's and surface intervals. :)

okay, didnt mean to start anything
but when will a proper report be made? and by who?

Once the investigation has been completed and an official report has been released, I'm sure that we'll read about it in the NACD and/or NSSCDS publications.

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Originally Posted by CaveDivingCop

Well we could discuss this till we're all blue in the face, but right now I think all there needs to be is prayers and support for Judi and Rudy.

Hang in there Judi....we're all praying for ya.

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I was not trying to do or say anything wrong I was asking a question and I am very worried about Judi but I know she is a very stuburn Lady and I mean that in a good way but my prayers are with her and her family. But I know if there is any chance at all she is tuff and she will be telling a story about it at a campfire someday. But yes lets all keep her in our prayers. Does anyone know her curent condition or any improvments of hope?

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Originally Posted by Gary

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Originally Posted by MikeH

Sure, you can breathe 100% helium....for about 2-3 minutes before you pass out, then die shortly thereafter due to the fact that there's no oxygen in it.

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I think it would be quicker then that. While you could hold your breath with a lung full of air for 2-3 minutes and survive for a while on the oxygen saturating your tissues breathing pure Helium would lead to a much more rapid and painless unconsciousness - likely even without warning.

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Originally Posted by http://yarchive.net/space/science/man_in_vacuum.html

The best Earthly comparison is what happens to people who walk into a room containing a pure-nitrogen atmosphere. The analogy is fairly good; to a first approximation, when there's no oxygen present, it doesn't matter whether something else is there or not. Such accidents happen occasionally in industry. (In fact, one happened at the Ariane 5 launch site a few months back.) Sudden loss of consciousness occurs within 10-15s, and death follows quickly.

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http://cavediver.net/phpbb2/viewtopic.php?p=7843#7843

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A few of my professional aquaintences have told me that walking into a 100% inert atmosphere has an immediate affect on the nervous system, and will cause it to do the equivalent of a "reboot". The problem is, while it's rebooting, you die, unless, as noted, you're rescued and CPR is performed as your system comes back on line. There seem to be quite a few things that happen, and I hate medicine so I try to understand them in as simple terms as possible. His "reboot" theory was the best analogy I've heard yet.

Mark

WOW, someone hasn't even come out of the ICU, and we are on the edge of new scientific breakthrough.