One way to experience narcosis is to go to 30M/100ft on air then switch to EAN34% for around 5 minutes, then switch back to air, guaranteed you will now feel narced.
Nitrogen Narcosis.
- Thread starter Tekk Diver
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I love my HOG Classic, you simply can not beat the value. I let my daughters boyfriend (my dive buddy) try my octo (same classic as my primary secondary) on the Red Sea in PCB at 65ft and he said it felt liked it would breath for you.
Eric Sedletzky
Contributor
I think you might have to go back a little further than 20 years to find some truelly miserable regs. Maybe some early diaphragm regs that had a small and thick diameter diaphragm that didn't allow the pin to move far enough to allow a generous flow of air at high demand. Materials have changed which allow wider and thinner diaphragms now for more flow. However some of those changes happened longer than 20 years ago.
As far as piston regs go, hardly anything's changed. Scubapro made some of the best stuff and the MK5 or 10 are still is regarded as some of the best stuff ever made. MK 20 might be 20 years old and takes the same kit as a current 25. Aren't MK25's supposed to be the deep king? The G250, same inerds as a 156, still the best breathers and most copied 2nd of all time.
If you're talking about companies like Dacor going out then yeah, I suppose that's a consideration, but I never really used Dacor so I have no idea about their deep performance.
Atomic I don't think is quite 20 years old yet (maybe) but it's close.
Aqualung had regs 20 years ago that are virtually identical internally to their regs today. What about Conshelfs? Has anybody ever used those deep, like the Navy?
The only thing HOG has over anybody nowdays is price and user obtainable parts. I'll take a few regs over 20 years old over a HOG any day. I just sold my HOG in favor of my over 20 year old regs.
I guess we could discuss Poseidon for deep performance and anti freeze up capabilities including one model from 1958.
The Chairman
Chairman of the Board
It's not just the reg either. It's also the upkeep on the reg. Either way, I've seen a half dozen instances where a reg has been over breathed. The panic it generates is total and it has always resulted in the diver bolting for the surface. Often this leads to some sort of baro-trauma and it's never pretty. Fortunately. I see it happen less and less as some of these "miserable regs" you don't think exist are aged out of the system. For the most part, modern regs are better than their ancient counter parts.
Pinecube
Contributor
Do you mean trimix? From what I've learned oxygen is comparably narcotic to nitrogen at depth.
DevonDiver
N/A
I was unaware, until very recently, of how hotly contested the unified theory of general anaethetic action, proposed by Meyer and Overton, was..
This is a good read: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701367/
There are two schools of thought on oxygen narcosis. Different agencies adopt different sides. Neither is yet proven, from what I know.
1. Oxygen narcotic potential. Meyer and Overton demonstrated the anaesthetic properties of gas in relation to their lipid solubility. Oxygen has a higher lipid solubility than nitrogen (see below) and, therefore, should be at least as narcotic from a neurological perspective.
2. Oxygen metabolizes. If narcosis is a product of elevated gas partial pressure, then oxygen should prove relatively low in narcotic effect. This is because oxygen metabolizes once inside the body... and the partial pressure of oxygen reaching the brain will always be substantially less than the inspired oxygen partial pressure (i.e. at ambient pressure).
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It's a bit counterintuitive though, in that you don't metabolize more oxygen just because PPO2 goes up.
Pinecube
Contributor
Thanks for the insights!
This is just me thinking out-loud, I am still learning...
Regarding #2, Oxygen metabolizes in the body, but does more O2 automatically mean more metabolizing? The body still has to bring forth the sugars/starches for it to take place.
Also if I'm remembering correctly, the blood(hemoglobin) can only handle so much oxygen, the rest (including any additional oxygen due to depth) will wind up in the solution. This amount of oxygen will certainly be a lot less than the amount of nitrogen, but that gap shrinks a bit when looking at that chart from #1 with O2 being 1.7 times more soluble than N2.
...It looks like I have some more reading to do.
DevonDiver
N/A
No, it doesn't mean more metabolizing, as that's demand necessitated, but nonetheless the ppO2 is lower in the brain than ambient pressure. That's all.
If I remember correctly (?), we metabolize circa 3% O2 (.21 -.18) from inhalation to exhalation. The product being CO2, which is also believed to be of high narcotic potential.
I'd be interested to know if anyone had references as to what the ppO2 is normally in the brain.
But it's 3% at 21%, not 3% by volume. The O2% we metabolize should go down as the pressure goes up. That is the part I also find counter-intuitive about nitrox: we replace some of N2 with O2 and get less N2 to off-gas, fine, but don't we have to off-gas the extra O2 then?
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