Nitrox and gas narcosis

[munitor]

I just did my NAUI nitrox course and have some questions about gas narcosis that were triggered by reading about the narcotic effects of gasses other than nitrogen.

Are the typical 32% and 36% mixes more likely to induce narcosis than air at a depth of 90 fsw?

If so, is this due to the contribution of the partial pressure of oxygen component, which has a higher lipid solubility (anesthetic effect) than nitrogen (e.g., 0.110 vs. 0.052)?

Is the narcotic potential of a mix proportional to the sum of the (partial pressure) x (lipid solubility) of the components? Because if it is, it looks like you don't just run into CNS MOD limits with nitrox, but that you might see narcosis about 10' and 20' shallower with 32% and 36% than you do air.

Thanks!

 

[BIGSAGE136]

Chances are reduced. Less Nitro.

 

[kidspot]

what kind of data backs up that statement Bigsage136? I know it has less nitrogen, but is Oxygen narcotic at depth also? Seems like everytime I hear people talk about it their views are different... so what kind of research is/has been done on the narcotic effects of Oxygen at depth?

 

[BIGSAGE136]

Oxygen is toxic at depth...although after hanging out with some of todays youth (guidance) I think they use the term interchangeably.

 

[triton94949]

I have not noticed a difference between narcosis with air compared with nitrox.

At 100 ft on air or on EAN36 I feel the same light buzz.

At 130 ft on air or EAN32 I feel the same mild buzz.

At 150 ft on are or EAN25 I feel the same moderate buzz.

Therefore I do not believe there is any difference between the narcotic factor of N2 compared with O2.

Helium (based on my experience) and Neon (based on my readings) are the only two gasses that reduce narcosis. We have about 10 years worth of remaining Helium reserves. We have an unlimited supply of Neon (the atmosphere). The only problem is that Neon is about 100 times more expensive than Helium. The good news is that they are both less narcotic than O2 or N2.

 

[wedivebc]

what kind of data backs up that statement Bigsage136? I know it has less nitrogen, but is Oxygen narcotic at depth also? Seems like everytime I hear people talk about it their views are different... so what kind of research is/has been done on the narcotic effects of Oxygen at depth?

Meyer-Overton Inert gas narcotic potential is proportional to its solubility in lipid tissue (oxygen is not inert)
Dalton's law Every gas in a container exerts a force equal to its partial pressure but acts as if it alone occupied that container.
This leads me to believe that the narcotic effect of individual gasses are not cumulative and that oxygen is not subject to the Meyer-Overton theory because it is not inert.

 

[triton94949]

...This leads me to believe that the narcotic effect of idividual gasses are not cumulative and that oxygen is not subject to the Meyer-Overton theory because it is not inert.

Dive it in varying fractions of O2 and see what you get.

I get no differences.

 

[wedivebc]

We have about 10 years worth of remaining Helium reserves. .

Maybe 20 years worth if people stopped wasting it on 60ft snorkel dives

 

[kidspot]

So because o2 is not inert (like nitrogen, helium & neon) it according to some theories remains non-narcotic (though toxic)

are there any other "safe" gases for your body that are not inert as well? perhaps some that would be less toxic at depth?

 

[wedivebc]

Dive it in varying fractions of O2 and see what you get.

I get no differences.

I dive rebreather and I have seen immediate changes in "buzz" when the PO2 drops, depth being constant. Only thing is my experience is opposite yours so I guess the whole thing is very subjective.