Nitrogen Narcosis - Deep air dives

[MaxBottomtime]

That's a huge difference. I've been watching TV, reading a book or having a conversation while thinking about something else. I would have missed what was going on while I was thinking about the other thing. I've never spent an hour or so doing something and as soon as it ended not being able to remember half of what just happened.

 

[Lorenzoid]

I think I'm the opposite of the drinker who doesn't know how impaired he really is. I am convinced I feel the very subtle effects of a single pint of 5% beer or glass of wine on my mental acuity, and that it increases ever so slightly with each additional gulp, and I am convinced that beginning at less than 100 feet I can feel the increasing effects of depth on my mental acuity. Oh, I'm sure the overall feeling is due to a combination of the gas narcosis and CO2 retention and maybe other things, but if they all tend to increase with depth, the precise cause doesn't matter that much to me. I know I'm at least a little impaired and that it increases with depth, beginning relatively shallow.

 

[BRT]

I think I'm the opposite of the drinker who doesn't know how impaired he really is. I am convinced I feel the very subtle effects of a single pint of 5% beer or glass of wine on my mental acuity, and that it increases ever so slightly with each additional gulp, and I am convinced that beginning at less than 100 feet I can feel the increasing effects of depth on my mental acuity. Oh, I'm sure the overall feeling is due to a combination of the gas narcosis and CO2 retention and maybe other things, but if they all tend to increase with depth, the precise cause doesn't matter that much to me. I know I'm at least a little impaired and that it increases with depth, beginning relatively shallow.

This is how I believe it is.

 

[drrich2]

From this thread and others, I've gotten the impression that nitrogen narcosis (not referring to CO2 narcosis, since work load during the dive can fluctuate levels) is often rapid onset with depth, and rapid resolution with ascent (as in someone with a panicky 'dark narc' experience might swim up 15 feet and shortly resolve it?).

Seems odd to me. While the mechanism, whatever it is, presumably isn't based on nitrogen bubbles (none since it's most problematic at the deepest portion of the dive), why is the onset so fast, and am I right in inferring that if you maintain depth and task load it doesn't seem to markedly progress if you stay there? Does it stay constant if you don't go deeper or work harder?

I don't know how soluble nitrogen is in the blood, how quickly nitrogen level in lung gas equilibrates to dissolved level in the blood, and from there into brain tissue. Does the water component of blood saturate with nitrogen at a given depth so fast?

I ask because in NDL algorithm and related discussions, people speak of tissue compartments, rapid & slow on-gassing.

Richard.

 

[Lorenzoid]

. . .
I don't know how soluble nitrogen is in the blood, how quickly nitrogen level in lung gas equilibrates to dissolved level in the blood, and from there into brain tissue. Does the water component of blood saturate with nitrogen at a given depth so fast? . . . .

The Meyer-Overton hypothesis says that it's a gas's solubility in lipids that relates to the narcotic effect, not solubility in the blood. But I suppose nitrogen first has to be transported via the blood, so I see your point--I think. Out of my depth here.

 

[rjack321]

From this thread and others, I've gotten the impression that nitrogen narcosis (not referring to CO2 narcosis, since work load during the dive can fluctuate levels) is often rapid onset with depth, and rapid resolution with ascent (as in someone with a panicky 'dark narc' experience might swim up 15 feet and shortly resolve it?).

Seems odd to me. While the mechanism, whatever it is, presumably isn't based on nitrogen bubbles (none since it's most problematic at the deepest portion of the dive), why is the onset so fast, and am I right in inferring that if you maintain depth and task load it doesn't seem to markedly progress if you stay there? Does it stay constant if you don't go deeper or work harder?

I don't know how soluble nitrogen is in the blood, how quickly nitrogen level in lung gas equilibrates to dissolved level in the blood, and from there into brain tissue. Does the water component of blood saturate with nitrogen at a given depth so fast?

I ask because in NDL algorithm and related discussions, people speak of tissue compartments, rapid & slow on-gassing.

Richard.

Most anesthetic gases are fairly rapid onset (a couple mins) eg. N2O (laughing gas at the dentist), N2 (diving), isoflurane (surgery) and related compounds. Almost universally these are all "inert" gases in that they are not metabolized. This is good because metabolism is almost always dependent on liver function and the most desirable anesthetic dosing is based on body weight not on something harder to measure like liver function. The reason the onset is rapid is two fold:
1) the lungs are directly connected to the blood stream, that's their role to exchange gases. Blood saturates with N2 really really fast as it passes through pulmonary capillaries.
2) the brain and central nervous system are highly perfused and in close interaction with the blood.

The assumption is that gaseous anesthetics act to physically disrupt nerve cell membranes and synapses but the precise mechanism(s) and interactions remain elusive. Hyperbaric anesthetics have even more variables to tease apart, the wiki is actually pretty good on this topic.
Inhalational anaesthetic - Wikipedia

 

[Landlocked123]

Yes i read somewhere also that it has to do with gas density and absorption in lipids. I also thought i read that it does not get worse as the bottom time increases. This makes no sense to me. It basically said that you are as narced as you will get withing the first couple minutes. One would think that the more Nitrogen the more narcosis...

 

[rjack321]

Yes i read somewhere also that it has to do with gas density and absorption in lipids. I also thought i read that it does not get worse as the bottom time increases. This makes no sense to me. It basically said that you are as narced as you will get withing the first couple minutes. One would think that the more Nitrogen the more narcosis...

Co2 can exacerbate narcosis (additively). But hyperbaric N2 roughly acts like other anesthetic gases, it saturates the sites that disrupt neural signals fairly rapidly because your brain is very well vascularized. Same basic reason you pass out before surgery or get loopy at the dentist rapidly.

 

[tomfcrist]

If you have never breathed helium in the 100-125’ range, i think you would be surprised.

Fact, but the difference isn’t nearly as drastic as this :

, it was like tithing in church. I did it to prove everyone wrong. Instead, I had to come to the realization that the masses were right, and I was an idiot. Almost instantly I felt a change. A fog I didn't even know was there cleared within seconds. I felt brilliant, alert, aware.

The difference between air and trimix on deep dives is absolutely night and day.

 

[Landlocked123]

I found this....