28% O2 vs. 32% O2: What a Difference

[contender]

Now people will be huffing Xenon bulbs.

With these qualities who can resist..."Xenon is non-toxic, although it does dissolve in blood and belongs to a select group of substances that penetrate the blood-brain barrier, causing mild to full surgical anesthesia when inhaled in high concentrations with oxygen." Stolen from Wikipedia.

[FW]

All of these points are well-taken. It doesn't make sense to trade nitrogen for oxygen for a dubious decrease in narcosis, and less deco time: The complications of O2 toxicity are certainly a lot worse than N2 toxicity. My bet is that even helium has some narcosis associated with it: that's the way it seemed to me in the back of DiePolder III several years ago. With limited PO2 and PN2, that was the only explanation.

Of course, perhaps it is all because I have a lower mental status to begin with!

But I agree with all of the assessments above: better to put up with the inconveniences of a higher PN2, than risk a potentially fatal O2 hit. I'll stick with 32%.

(Incidentally, I don't consider the Devil's Ear/Eye system a "high flow" system, if you know where the sweet spots are!)

Try some Trimix 30/30, and see if it helps at Devil's Eye.

[divindoc]

After an apparent 02-induced seizure and fatality @ Devils several years ago, my team discussed what %02 we felt comfortable diving, and decided to dial back to 31% for that system, for an extra buffer at depth. So many variables go into determining a "safe" level of 02 exposure at depth that we thought as GWB1 would say, this was "prudent".

[Sludge]

Looks like i'd like to brew up a little xenonox for the next galaxy dive at ginnie...

Didn't Sheck decide even Argox was WAY too narcosis-inducing? Xenonox would be about ten times as bad, right?

Seems like Argox would be the mix of choice.

[fixxervi6]

I think that 99% of felt nacrosis is state of mind, if you go in thinking, I"m on 32 I won't narc as much, you won't, if you go in on air thinking, damn I'm gonna narc, your gonna narc. I've seen people totally go blitzo at 80 feet on nitrox - and it was their state of mind that did it to them, you can tell who is gonna freak before you even get in the water sometimes.

Usually its the hoovers (from what I've observed) that narc out to the point you have to grab them because their pupils do that cartoon thing, so my non professional opnion about that is, they are hoovering due to discomfort/anxiety mix that with a touch of narcosis and flipzoid

I can tell "something is up" as shallow as 60 feet, my complex mental math skills (not that I have many to start with) start to be affected around 60 feet, when I get to 90 - 100 ish I can tell when I've hit the depth just by "how I feel".

Around 150 feet my motor skills start getting impacted, so I've decided that was my max depth on air that I would do, ever, just because my hands don't work as well, I have to move real slow working clips etc so I figure thats deep enough, espeically with helium now.

On trimix I count o2 as narcotic, my buddy I dive mix with doesn't.

I've dove 30/30 in Devils and I thought it was a perfect mix for the dive

Dark Eternal - I'd be curious how your wife would feel if you slipped her some 21 and told her it was 32 obviously not a good idea, but the results would be interesting, it would rule out the placebo affect.

First time I took my wife down to 120 on air in a nasty lake, I asked her how she did when it was over, she was like, everything was fine I couldn't tell a difference, I said, thats becase you were narcin, if you are at 120 and you "are not narcing" and feel 100% normal, that means your narced

[scububa]

As a fellow 1958 model, I cling to the idea that "geezer gas" reduces fatigue! Don't go bursting my (Nitrox) bubble!

I forget who said it - "The great tragedy of science - a beautiful theory destroyed by an ugly fact."

Mike

"The great tragedy of Science - the slaying of a beautiful hypothesis by an ugly fact."
Thomas Henry Huxley

[wingman]

This thread has got me thinking, i always wondered why i was so addicted to diving, it's the nitrogen. Nitrogen is your friend. I am going to start trying varios hypoxic bimixes (maybe just hypoxic nitrox works as a term as well). Maybe a nice nitrox 16.

[Sludge]

Come by one of the shops where I work and I'll fill your cylinder with normoxic nitrox for six bucks!

[apitkin]

This thread has got me thinking, i always wondered why i was so addicted to diving, it's the nitrogen. Nitrogen is your friend. I am going to start trying varios hypoxic bimixes (maybe just hypoxic nitrox works as a term as well). Maybe a nice nitrox 16.

Actually Bill, you're not too wide of the mark. Narcosis and anesthesia are just different points on the same spectrum. In the early days of dental anesthesia for children, it was common practice to give them 100% nitrous oxide, as the hypoxia helped get them asleep faster. A little oxygen (maybe 10%) would be dialled in when they got really blue!

Andy

[Dark Eternal]

I think that 99% of felt nacrosis is state of mind, if you go in thinking, I"m on 32 I won't narc as much, you won't, if you go in on air thinking, damn I'm gonna narc, your gonna narc. I've seen people totally go blitzo at 80 feet on nitrox - and it was their state of mind that did it to them, you can tell who is gonna freak before you even get in the water sometimes.

Usually its the hoovers (from what I've observed) that narc out to the point you have to grab them because their pupils do that cartoon thing, so my non professional opnion about that is, they are hoovering due to discomfort/anxiety mix that with a touch of narcosis and flipzoid

I can tell "something is up" as shallow as 60 feet, my complex mental math skills (not that I have many to start with) start to be affected around 60 feet, when I get to 90 - 100 ish I can tell when I've hit the depth just by "how I feel".

Around 150 feet my motor skills start getting impacted, so I've decided that was my max depth on air that I would do, ever, just because my hands don't work as well, I have to move real slow working clips etc so I figure thats deep enough, espeically with helium now.

On trimix I count o2 as narcotic, my buddy I dive mix with doesn't.

I've dove 30/30 in Devils and I thought it was a perfect mix for the dive

Dark Eternal - I'd be curious how your wife would feel if you slipped her some 21 and told her it was 32 obviously not a good idea, but the results would be interesting, it would rule out the placebo affect.

First time I took my wife down to 120 on air in a nasty lake, I asked her how she did when it was over, she was like, everything was fine I couldn't tell a difference, I said, thats becase you were narcin, if you are at 120 and you "are not narcing" and feel 100% normal, that means your narced

It actually happened the other way around. Every time she had been past 90' on 21 she had gotten narced. We were at JB and at the end of the dive she was like "I was not narced at all - that was a great dive" She thought she was breathing 21 but had in fact had grabbed the tank with 32%. I guess there is an argument for labeling your tanks better than we did. Like I said - not scientific at all but now she only dives 32% in the mill pond and is fine. Maybe its placebo - but it works for her. Personally I cant tell a difference between air and 32% up to MOD of the 32%.