Should 'Hypercapnia Experience' Be Part Of Training?

caveseeker7

Mdemon brought up an intresting subject in another CO2 related thread:
Purposely having a CO2 hit for experience's sake.

It is well known that there are signs of CO2 poisening, but everyone responds to it in a different way, probably even on different dives. A high tolearance (or is it low level of CO2?) can just cause a headache and the problem be dealt with. A low tolerance (or high CO2 level) can be absolutely debilitating as several accounts have shown.

So should a 'hypercapnic experience' be part of the rebreather training?
What kind of protocol should be in place to make it safe?
Is the risk worth the knowledge gained?

Right now I'm at the same spot Mdemon is:

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Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

schford

Good question Stefan,

I picked I am in two minds - principally as i heard that the symptons can vary considerably especially 1 ATA vs multiple ATAs. so you might feel confident that you would know what a hit woudl feel like, don't feel the exact thing on the dive, so don't go open loop, so who knows what!???

Stuart

Divechick

I am pretty sure I managed to give myself a C02 hit from inside a sleeping bag many years ago ...

I was doing a walking expedition and camping out and it was damn cold at night, so I had scrunched right down inside the sleeping bag and tightened the drawstring hood thing at the top in an effort to keep warm. Presumably what happened was that the C02 built up inside the sleeping bag. I ended up puffing like a train before I had the sense to put my head back out the top. I didn't realise what it was at the time - assumed I had somehow managed to deplete the oxygen inside the sleeping bag or something - but since being trained on a rebreather I recognise the symptoms of hypercapnia. So beware - those sleeping bags could be lethal!

caveseeker7

Does that mean you and your sleeping bag will volunteer for my experience?
Think I just changed my opinion.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

wedivebc

Having once experienced a level of discomfort after a series of dives which was probably due to increased CO2 I feel that I would recognize that symptom again should it occur. If there was a way to simulate a mild onset like that for a student without the danger of a serious hit I would say definately yes but I am not sure how you would initiate a 'mild' hit.

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Cheers,

Dave....

Man is the only animal burdened with the knowledge he will eventually die

Divechick

Certainly - will be happy to assist by zipping you into a sleeping bag and leaving you there!

TechBlue

Personally I don't think an induced hypercapnia hit is worth the potential danger. In most cases even when you have a student finning against the wall in a pool with an empty scrubber they are waiting and watching for symptoms and even while they are totally focused many simply fin until they passout, for others who do feel the symptoms many get a false sense of security that they can easily handle a Hypercania hit. As any of you know when you do take a hit at depth you may be aware that all is not well but the paranoia and lack of confidence that accompanies it can take extreme effort to go off the loop and switch to a bailout reg (another good reason for a OC/CC DSV) and this is where your skillsets come through.

ROB DAVIE

I would have to say that I agree with Cris on that score. Especially since hypercapnea symptoms are like those of oxygen toxicity in this sense; they vary from diver to diver, and within each diver from day to day, both in their intensity and manner of onset.

I don't believe that the "CO2 pool experience" actually produces any worthwhile learning, except for the very real observation that: "Hey, that caca is nasty!!"

Just my PPO2's worth.

Cheers!

Rob

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"CC Rebreathers will become a viable part of tech diving WHEN PIGS FLY!!"--GI3

Pierre Farrugia

I too agree that if during the course you handle it and feel it coming can make you believe that next one you will feel it too but who or what garantee you so !

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Pierre Farrugia

My wife told me " If you don't quit diving I'm going to leave you"
My reply " God, I'll miss you"

www.atlam.org www.divemed.com

Steve

I'm with you guys on this. The Aussie Navy removed this componend of their training in about 1993 for these very reasons. It was concluded that the set of warning signs the diver learns were rarly the same for each CO2 event and therefore that it was counterproductive to teach it.

They, like most of us, now work on the theory of "if in doubt, bailout". I'm sure we could explore the best way to bailout at length but Chris pretty much nailed it. Given the way one reacts, I mean, even though they know they should get off the loop and yet they can't, surely an OC/CC DSV and a good buddy are the best help. Well that, or the lightest, fastest, biggest, bestest most expensive rebreather in the world