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

[debajo agua]

Can someone please explain to me, why a diver using a gas mix of EANx, won't help reduce the susceptibility to Nitrogen Narcosis?

According to Dalton's Law, it all seems very simple: less N2 into cells = less risk of getting N Narcosis.

My cert. agency sights "inconclusive evidence" and "Oxygen Narcosis" as off setting factors but they didn't offer any more information. I've never heard of anyone getting narcd off O2, if it was possible, I'm sure it would would be a worldwide epidemic. Are the agencies referring possible hyper-ventilating like effects to the body (e.g. dizziness, tingling) from breathing EANx. If so, It was never mentioned to me as a problem breathing EANx. What's going on here?

Unless I'm mistaken, isn't one of the purposes of using Trimix to remove Nitrogen, and replace it with another inert gas, for the purpose of maintaining a clear head at depth? Can't EANx play the same role?

Help me make sense of it all.

TIA

 

[Cave Diver]

Helium has a lower narcotic effect than Nitrogen or Oxygen, which is why Trimix is used for deeper dives.

Oxygen and Nitrogen both show evidence of high narcotic effects, so Nitrox alone may not have a noticeable effect on narcosis.

 

[t-mac]

Nitrox isn't used to reduce narcosis. You're right that you are probably getting less "nitrogen" narcosis, but oxygen is believed to be just as narcotic because or similar chemical properties that allow it to interfere with neural signalling. You're right that oxygen narcosis is not as well characterized as nitrogen, but that's probably because it causes CNS toxicity before narcosis under conditions that would allow you to study it.

Trimix is different because you are adding helium, which is not narcotic -- you are diluting both oxygen and nitrogen here.

 

[Dr. Lecter]

I've never heard of anyone getting narcd off O2, if it was possible, I'm sure it would would be a worldwide epidemic.

Indeed it would, because there's a ton more oxygen than nitrogen in our atmosphere.

No, wait...

 

[chrpai]

Trimix is different because you are adding helium, which is not narcotic -- you are diluting both oxygen and nitrogen here.

Can you go into that more? I'm not a tech or trimix diver so when is it approriate to say helium is not narcotic and when is approriate to say that it's not *as* narcotic?

The narcosis of trimix and the calculation of END

 

[elan]

I feel the narc on my dives comes mostly from CO2; when we swim I feel more narced than when we scooter...

 

[electrix]

Everyone is different, nitrogen narcosis could be like alcohol, one shot for me and I am ok one shot for someone else and they get falling down drunk. We are humans not machines.

 

[Cave Diver]

http://www.scubaboard.com/forums/diving-medicine/21360-narcotic-potency-helium.html

 

[t-mac]

Can you go into that more? I'm not a tech or trimix diver so when is it approriate to say helium is not narcotic and when is approriate to say that it's not *as* narcotic?

The narcosis of trimix and the calculation of END

I'm not either and this is a grossly overbroad assertion on my part, making a sharper point than exists in reality. According to this link helium is 23% as narcotic as nitrogen or oxygen. I probably should have said that helium is *much less* narcotic than nitrogen or oxygen to the extent that the practical effect of trimix is that is *substantially reduces* narcosis at an equivalent depth compared to air or nitrox. Still explains why trimix reduces narcosis, but nitrox doesn't. Sorry for the misuse of absolute terminology.

 

[nimoh]

do a google search on "Meyer-Overton Theory"

It claims a relationship between solubility in a liquid and narcotic effects, and indicates that helium is far less narcotic than both nitrogen and oxygen, while oxygen is actually more narcotic than nitrogen, even though in diving they are usually assumed to be equal.