Oxygen Narcosis

[Eric Sedletzky]

I got a pretty hard hit on 36% once diving the Delgada Trench up on the lost coast of Northern California. Kind of freaked me out, way worse than any plain air hit I've ever had.
I don't like 02 narc at all, nasty nasty.
I much prefer a good air drunk.

 

[kelemvor]

Seems like oxtox would be a far greater concern than o2 narcosis. Is this a "basic scuba discussion?"

 

[ajduplessis]

Can I get a refund for the 2 min I wasted in reading this.

 

[NAM001]

Im no authority here but,,,, would it be fair to say they are both narcotic and becaue of the gas percentage N2 hits first and then much deeper O2 hits. This would explain why rec diving regards N2 as the narcotic gas by a perhaps 5 to 1 margin. and only when you get to trimix do they both caunt as narcotic because of the content percentage resulting form teh He dilution of hte N2. so that a 30/30 mix would for all purposes make the N2 and O2 equal participants in the narc process. Just guesing here. I like this discussion.

---------- Post added November 11th, 2014 at 11:45 PM ----------

How do you tell the differnce bewtween N2 and O2 narcing????

I got a pretty hard hit on 36% once diving the Delgada Trench up on the lost coast of Northern California. Kind of freaked me out, way worse than any plain air hit I've ever had.
I don't like 02 narc at all, nasty nasty.
I much prefer a good air drunk.

 

[kwinter]

Some of this is just plain silly. If you're going to consider both N2 and O2 narcotic from the surface, then you should be planning your gasses to match surface pressures. So a dive to 30m/100ft should have a bottom gas of 5/75, and a tank of air as a travel gas. If you're that concerned about the narcosis level of O2 at shallow depths, perhaps diving is not for you.


iPhone. iTypo. iApologize.

 

[boulderjohn]

Im no authority here but,,,, would it be fair to say they are both narcotic and becaue of the gas percentage N2 hits first and then much deeper O2 hits. This would explain why rec diving regards N2 as the narcotic gas by a perhaps 5 to 1 margin. and only when you get to trimix do they both caunt as narcotic because of the content percentage resulting form teh He dilution of hte N2. so that a 30/30 mix would for all purposes make the N2 and O2 equal participants in the narc process. Just guesing here. I like this discussion.

---------- Post added November 11th, 2014 at 11:45 PM ----------

How do you tell the differnce bewtween N2 and O2 narcing????

Here is a quick explanation....

According to the theory currently held on what causes narcosis, all gases are to some degree narcotic, but some are more narcotic than others. According to that theory (the Meyer-Overton correlation), we would predict that oxygen should be more narcotic than nitrogen. The problem is that some of the oxygen we inhale is metabolized and would therefore not be available to cause narcosis. We further have the problem of not being able to test it well, since at high dosages the test subject would be likely to have a toxic reaction. There is no way to tell the difference between narcosis caused by one gas and narcosis caused by another. In all likelihood, they work together. I don't know the curriculum for all nitrox courses for all agencies, but the two I do teach for and the one from which I took additional courses all teach that nitrox is considered to be about as narcotic as air for that reason. I am unaware of any agency or reputable source teaching otherwise.

Again according to theory, one of the least narcotic gases would be helium. Helium becomes an increasingly greater percentage of standard breathing gases as divers go deeper and deeper. This lowers the amount of both oxygen and nitrogen in the breathing mix, which counters the risk of both oxygen toxicity and narcosis. The experience of technical divers using helium supports that theory that helium is less narcotic.

 

[mmerriman]

New PADI OW course - "For example, what was once called “nitrogen narcosis” will now be known as “gas narcosis,” which is a more accurate description since several gases can exert the same effects as nitrogen on the body at depth."

 

[Dr. Lecter]

The experience of technical divers using helium supports that theory that helium is less narcotic.

Though as you get to a significantly higher ppHe, it still has some problematic effects on the CNS. HPNS is no fun.

 

[Eric Sedletzky]

How do you tell the differnce bewtween N2 and O2 narcing????

I notice higher percentages of 02 begin to have an affect at 80 to 90 feet, before max PP02.
It's an irrational paranoia that just makes me not want to be down there. It kind of a trip out feeling that I don't care for. I normally only use nitrox on charter boats down south because we can't get it up here. On a two day charter I use it and deal with it because we do 5 -6 dives a day and I know it's better for me.
When I dive air at the same depths I don't notice any affects. I Generally need to go past 130 on air to realize any significant narcosis.
However, I got significantly narced on air once at 70 feet after shooting a fish and stringing it, I for the life of me couldn't figure out how to rewind the shooting line and reload my gun even though I'd done it a thousand times before, I just stared at it.
I think narcosis has a lot to do with personal tolerance, amount of rest before the dive day, amount of alcohol the night before, amount of usable fuel available from a good meal, dive conditions, stress levels, preoccupation or distractions with other matters besides the dive at hand, and many other factors.

 

[100days-a-year]

Since it is nearly impossible to quantify even the predicted effects of 02 narcosis much less the actual and that N2 narcosis will likely occur sooner and be more noticeable I tend to ignore it.Not to mention that no matter the source narcosis occurs and is variable between divers,dives,dive conditions etc..I consider P02 only for Oxtox and PN2 only for narcosis.For a real joy do some ARGOX dives,shallow ones I suggest.