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

[electrix]

Once you get this all figured out to 6 decimal places, it won't matter !!! You will not know how it is going to effect you until you find out how it is going to effect you in the water. You may get to 90' and not be able to remember your name or it may not have any effect at all, you will not be able to figure it out with a calculator though and that is for certain.

 

[PfcAJ]

Roles of nitrogen, oxygen, and carbon dioxide in compressed-air narcosis

[abstract] DOES OXYGEN CONTRIBUTE TO THE NARCOTIC ACTION OF HYPERBARIC AIR?

Here ya go, guys.

 

[boulderjohn]

how it was arrived at the conclusion, that O2 is equal to N2 in it's narcotic effects on the human body. T

To be honest, no one is really totally sure. The best estimates are based on the Meyer Overton correlation. It correlates the narcotic potential of gases with certain characteristics--especially lipid solubility. It seems to work out pretty well with narcosis. According to the correlation, helium should be less narcotic than either oxygen or nitrogen, and that sure seems to be the case. According to this correlation, oxygen should be more narcotic than nitrogen. The joker in this deck, though, is that because some oxygen is metabolized, it is hard to estimate the narcotic potential of the rest.

The highest PPO2 I will breathe is 1.6, with the greatest amount of time on that spent on a 20 foot deco stop on oxygen. That is not a high PPO2 in terms of creating a narcotic effect, and I am not on it for lots of time because I take breaks to lessen the harmful effects on the lungs of breathing pure oxygen. If oxygen is as narcotic as N2, I would have to take the PPN2 to about 3.4, which I do not plan to do to satisfy my curiosity.

 

[jonnythan]

I see, so if both O2 and N2 have the same narcotic potential (I believe both are currently assigned 1.0), then by logic, a diver should feel the narcotic effects of 100% O2 at least between 2.0 ata or 3.0 ata.

What? No. If O2 and N2 have the same narcotic potential, you'll get narced at the exact same depth no matter the proportion of O2 and N2 (provided that the gas you're breathing is composed entirely of O2 and N2).

If you get narced on air at 100 feet, you'd get narced on 100% O2 at 100 feet as well (if you didn't black out first).

Say O2 and N2 both have a narcotic rate of 1. On air at 100' you've got about 3.16 ata of N2 and 0.84 ata of O2. That's 4 ata of narcotic gas with a rate of 1, or 4 narcotic units. On EAN32, you've got 2.72 ata of N2 and 1.28 ata of O2. Again, 4 narcotic units.

If you breathe O2 at 3 ata, that's 3 ata of narcotic gas, or 3 narcotic units. That's not enough to narc you.

Now say you're breathing 18/45 (18% O2, 45% He, 37% N2). Let's assume Helium has 0 narcotic rate. At 100 feet you have 0.72 ata of O2 and 1.48 ata of N2 (and 1.8 ata of He). That's 0.72+1.48 or 2.2 ata of narcotic gas. Not enough to narc you.

I know it sounds if I'm being difficult, but I'm really trying to understand how it was arrived at the conclusion, that O2 is equal to N2 in it's narcotic effects on the human body.

You could reach that conclusion by switching back and forth between air and EAN36 at 100 feet to see which one, if either, narcs you more. If you're approximately equally narced on both then the O2/N2 ratio has no effect on narcotic potential and O2 narcs you just as much as N2.

Don't confuse narcotic potential with oxygen toxicity or tissue diffusion/deco obligations. Narcosis is not something that persists - it goes away immediately with the removal of the gas pressure.

 

[MXGratefulDiver]

Suppose I drank four shots of Jack Daniels and took two hits of of a good green bud.

Now what if instead I drink only three and a half shots of Jack Daniels and took three hits of bud.

Which would make me feel less narc'd?

Jonnythan, nice to see you back on the board ...

... Bob (Grateful Diver)

 

[jonnythan]

Jonnythan, nice to see you back on the board ...

... Bob (Grateful Diver)

Ah! I have clearly been away long enough that everything about me but my name has been forgotten

 

[chrpai]

Ah! I have clearly been away long enough that everything about me but my name has been forgotten

I know the feeling!

 

[debajo agua]

I called a Dr. in the field of hyperbaric medicine today, and I'm awaiting a call back. Hopefully, he won't be too annoyed with me asking questions. I'll relay back, what he has to says about O2 narcosis.

The Dr. call me back. His credentials are without question: one of first 100 from NOAA to start teaching Nitrox; he designs and builds hyperbaric chambers and submarines; his business in hyperbaric medicine and therapy. Here's what he had to say:

Oxygen has no narcotic effect on divers at depth, in the chamber, or anywhere else. It does have a toxic effect, when breathe at increased pressure but no narcotic effect whatsoever. I asked this question in several different ways, I even quoted from my SSI Nitrox manual... he laughed. He reiterated, it has absolutely no narcotic effect. He said there is no such thing as O2 narcosis.

Furthermore, I told him about the controversy on SB of Nitrox displacing nitrogen...could it be argued that a diver is less likely to get narced. He stated technically the point is correct, but the amount of N2 it displaces is a very small percentage, and therefore, a diver could still get narced on Nitrox. I asked, but technically a diver is less likely to get narced on Nitrox than air because it displaces N2, he said, technically yes.

I asked him, since O2 toxicity effects the CNS could it, at higher ata, have an effect like aspirin. He stated that it's very minimal, and a patient is likely to suffer a grand mal sezuire beforehand.

He said that, whomever I'm discussing this with is probably confusing O2 toxicity with narcosis. Oxygen is not narcotic.

I'm just relaying what he told me. If you msg me, I'll provide you with his credentials.

 

[boulderjohn]

The Dr. call me back. His credentials are without question: one of first 100 from NOAA to start teaching Nitrox; he designs and builds hyperbaric chambers and submarines; his business in hyperbaric medicine and therapy. Here's what he had to say:

Oxygen has no narcotic effect on divers at depth, in the chamber, or anywhere else. It does have a toxic effect, when breathe at increased pressure but no narcotic effect whatsoever. I asked this question in several different ways, I even quoted from my SSI Nitrox manual... he laughed. He reiterated, it has absolutely no narcotic effect. He said there is no such thing as O2 narcosis.

Furthermore, I told him about the controversy on SB of Nitrox displacing nitrogen...could it be argued that a diver is less likely to get narced. He stated technically the point is correct, but the amount of N2 it displaces is a very small percentage, and therefore, a diver could still get narced on Nitrox. I asked, but technically a diver is less likely to get narced on Nitrox than air because it displaces N2, he said, technically yes.

I asked him, since O2 toxicity effects the CNS could it, at higher ata, have an effect like aspirin. He stated that it's very minimal, and a patient is likely to suffer a grand mal sezuire beforehand.

He said that, whomever I'm discussing this with is probably confusing O2 toxicity with narcosis. Oxygen is not narcotic.

I'm just relaying what he told me. If you msg me, I'll provide you with his credentials.

Wow! An anonymous source who contradicts all known research on the subject and laughs at those who believe all published research.

You should call him back and tell him he should publish his findings. he will be famous in no time.

 

[debajo agua]

Wow! An anonymous source who contradicts all known research on the subject and laughs at those who believe all published research.

You should call him back and tell him he should publish his findings. he will be famous in no time.

He's not anonymous... msg me and I'll provide you his information.