Nitrox Not Helping With Narcosis... It's not making sense.

[Blackwood]

Did you discuss with him any of his works with NOAA on micro-bubble research with Nitrox? Did you ask him his creditability as part of the first 100 original Nitrox instructor in the USA and his hyperbaric medicine credentials? I know he teaches hyperbaric technology here in Florida. He also builds chambers and subs. Pretty impressive resume if you ask me.

Credentials don't necessarily equate to credibility. For example, the author of this article is a scientist, an Instructor Trainer, an officer with CMAS, and yet he believes (and perhaps teaches) that air creates gravity, and that astronauts "float" because they've left the atmosphere and are thus no longer burdened with the (self-created) weight of air. What they're floating on remains a mystery.

Point is, while your contact has an impressive resume, it's not particularly relevant to understanding neurology/anesthesiology/etc. His reasoning that "they must be confusing it with toxicity" is pretty weak.

Anyway, since assuming oxygen is narcotic doesn't adversely affect dive planning, I'm personally comfortable treating it as such until it is shown to be incorrect.

*shrug*

 

[FinnMom]

So if O2 is not narcotic, how does your mystery expert explain your 1st-hand experience that EAN is not less narcotic than air?

Or in the words of Dr. Phil. "Howz the O2 not narcotic theory workin for you?"

 

[Dive the World]

People might have touch up on this -

Narcosis is not just about nitrogen - it is about nitrogen as much as it is about other factors.

One of my instructors quoted someone once - I paraphrase - All tables and diving related things you have studied are wrong BUT very useful.

I have been done 40-50m dives without getting narcosis - but know people if you had that effect at 20 meters.

Technical divers I know start hydrating three four days ahead of their dives and get plenty of sleep and rest before the dive.

IT is not just nitrogen - it nitrogen and the night before, the boat ride to the dive site - the stress of perhaps diving with new people - the sandwich you gobbled up for breakfast and extra cups of coffee - task loading trying to get the anchor unhooked...

Chemistry and physics is part of it, there is biology in it too and psychology - it all combines to determine ones limitations.

 

[debajo agua]

People might have touch up on this -

Narcosis is not just about nitrogen - it is about nitrogen as much as it is about other factors.

I remember reading somewhere: Nitrox isn't about putting oxygen into the air you breath, it's about taking Nitrogen out of the air you breath, there's nothing specific about O2 other than it's cheap and convenient. Perhaps a bit over-simplified but Nitrox 101. I also remember reading Shadow Divers and how Trimix was a voodoo gas in the 90's. The descriptive difference those early divers felt between diving air and Trimix. The tunnel vision, the sounds of banging drums inside their heads, the distortion of thoughts while breathing air, to the clarity they experienced while breathing Trimix. This was all made possible by replacing Nitrogen content in the breathing mix with another inert gas. To me, this same principle would seem to apply, albeit a much lesser degree, with Nitrox.

As a health care professional and someone who works regularly with O2, I had never heard anything, not one word, about O2 being narcotic, and as I'm relatively new to diving, the concept of O2 being narcotic when under higher PSI, intrigues me. I want to understand why people are not getting "O2 narced" in hyperbaric chambers? When diving, why is it that O2 seems to be arbitrary assigned the same narcotic potential as N2; especially, when there's controversy if it has any narcotic affect at all. Where did the idea come from and when did tech divers start calculating "O2 narcosis" into their profiles?

 

[DevonDiver]

there's nothing specific about O2 other than it's cheap and convenient. Perhaps a bit over-simplified but Nitrox 101.

Not really. Oxygen is a metabolized gas. Other gases, frequently used for diving, such as helium, are inert gases (not metabolized). That makes a big difference in saturation/decompression.

If helium were convenient and cheap, it still wouldn't make a great supplement for extending NDLs on dives not subject to narcotic partial pressures of nitrogen.

I also remember reading Shadow Divers and how Trimix was a voodoo gas in the 90's. The descriptive difference those early divers felt between diving air and Trimix. The tunnel vision, the sounds of banging drums inside their heads, the distortion of thoughts while breathing air, to the clarity they experienced while breathing Trimix. This was all made possible by replacing Nitrogen content in the breathing mix with another inert gas. To me, this same principle would seem to apply, albeit a much lesser degree, with Nitrox.

I don't see a 'principle' there, just a pet theory. Helium is less narcotic than nitrogen - that is all.

Again, Oxygen is not an inert gas.

I want to understand why people are not getting "O2 narced" in hyperbaric chambers?

Someone already mentioned - oxygen toxicity comes into play before you can study narcosis at high PPO2.

When diving, why is it that O2 seems to be arbitrary assigned the same narcotic potential as N2; especially, when there's controversy if it has any narcotic affect at all. Where did the idea come from and when did tech divers start calculating "O2 narcosis" into their profiles?

Tech divers don't calculate "O2 narcosis" or "nitrogen narcosis". They calculate "air narcosis". That is why, when considering the formulation/choice of %He in their mix, you will hear reference to "Equivalent Air Depth", to describe narcosis potential.

Air narcosis is considered equal to nitrogen narcosis, as you have mentioned, because it ignores variation in %O2 and %N. That's arbitrary because the exact mechanism of narcosis is not fully understood - and what little evidence exists, points towards no significant deviation in observed narcosis when the nitrogen/oxygen balance is altered.

If oxygen did have less narcotic potential than nitrogen, then it would still constitute little, or no value to the diver - as increasing %O2 to prevent narcosis at deeper depths would lead to toxicity issues long before any significant narcosis issues were solved.

 

[GrimSleeper]

As a health care professional and someone who works regularly with O2, I had never heard anything, not one word, about O2 being narcotic, and as I'm relatively new to diving, the concept of O2 being narcotic when under higher PSI, intrigues me. I want to understand why people are not getting "O2 narced" in hyperbaric chambers? When diving, why is it that O2 seems to be arbitrary assigned the same narcotic potential as N2; especially, when there's controversy if it has any narcotic affect at all. Where did the idea come from and when did tech divers start calculating "O2 narcosis" into their profiles?

As a health care professional, I'd assume you're using oxygen at an inspired ppO2 of, at most, 1.0 atm. In a hyperbaric chamber, patients are usually at a maximum pressure of 2.8 atm - not a depth where one would expect to notice the effects of narcosis from any source. So why would anyone, under those specific circumstances, care about O2 narcosis?

TS&M has already given you an excellent exposition of the Meyer-Overton correlation, Devon Diver has already pointed out that Helium is used in Trimix because it is less narcotic (and, coincidentally, it is believed to be less narcotic because it is less soluble in lipids...). You seem determined to prove something that is, actually, irrelevant. In the depth range Nitrox can safely be used in, you can't really make enough of a difference in inspired partial pressures of O2 or N2 to be able to test how relatively narcotic they are. Go beyond those ranges, and you need to start reducing the O2 content of your breathing gas anyway, to avoid CNS toxicity.

The difference in equivalent narcotic depths is too small to be able to really tell the difference anyway. Take 32% to 33m, and if you treat only N2 as narcotic your equivalent narcotic depth is 27m instead of 33m. So the argument is moot anyway, surely?

 

[CamG]

I'm an old dude ... I forget lots of things ... ... Bob (Grateful Diver)

I would bet that you do not miss much!
As always Bob your interjections are never missed by me!
Love it keep up the good work!

CamG

 

[antattack]

Wikipedia is a poor source because it lacks the documentation needed to support the information presented there. Where did you get your numbers from?

---------- Post Merged at 04:25 AM ---------- Previous Post was at 04:18 AM ----------

"Recreational Trimix Diving" by Kevin Evans and Richard Johnson​

 

[wedivebc]

I just re-read a thread I posted to on a rebreather forum in 2006 and although many of my beliefs from that time have changed or grown I do still believe that oxygen has much less effect on narcosis than N2. I also believe that the ratio of oxygen to nitrogen in a nitrox mix is such that there is not a big enough change to make a noticable difference one way or the other. There is yet to be any scientific data to support either claim and so for my money when calculating trimix blends I tend to ignore the oxygen component and deal strictly with the reduction of nitrogen.

 

[falcon125]

Very interesting thread, thanks to all who gave me a better understanding of what is going on inside me while diving. And to those who kept it going to the point of amusement.

These 2 quotes made the most sense to me.

humans love to categorize things

All tables and diving related things you have studied are wrong BUT very useful.

2 thoughts hooked together is an understanding.
It take an ego to proclaim it truth.