DIR- GUE Is it worth taking Fundamentals this late in the game?

[ginti]

At the risk of a second thread diversion,

Given the direction it took, I would say "in the hope of a second thread diversion"

is there any change in consensus about whether or not oxygen is narcotic after the Vrijdag article?

Vrijdag XCE, van Waart H, Sames C, Mitchell SJ, Sleigh JW. Does hyperbaric oxygen cause narcosis or hyperexcitability? A quantitative EEG analysis. Physiological Rep. In press, 2022

My vote is "No".

My vote is: "scientists have no clear answers yet, so let's take the most conservative approach". Is it a valid option?

 

[crofrog]

My vote is: "scientists have no clear answers yet, so let's take the most conservative approach". Is it a valid option?

Does it even matter. Treat it like a narcotic and worst case is you have less narcosis. People trying to save money on gas while tech diving is wild to me. Tech diving is expensive, I wish it wasn't, but it is. It's also risky the fact that people try to save some bucks on mix while increase the risk to themselves and others is crazy.

 

[jadairiii]

At the risk of a second thread diversion, is there any change in consensus about whether or not oxygen is narcotic after the Vrijdag article?

Vrijdag XCE, van Waart H, Sames C, Mitchell SJ, Sleigh JW. Does hyperbaric oxygen cause narcosis or hyperexcitability? A quantitative EEG analysis. Physiological Rep. In press, 2022

My vote is "No".

I'm a scientist (political scientist), there seems to be a correlation between the density of gases and their narcotic effect. Oxygen is not to far off from Nitrogen. So, logically, one would draw a conclusion that O2 is right around N2 as it relates to narcotic effect. That said, we metabolize O2 at a much greater rate then N2 (if I remember, N2 is metabolized, but very little).

That said, my own experience, I found when diving trimix with the same HE but increased O2, I would "feel" it. And this was before people started saying O2 was narcotic. FWIW.

 

[rsingler]

I found when diving trimix with the same HE but increased O2, I would "feel" it. And this was before people started saying O2 was narcotic. FWIW.

Interesting observation.
Is it possible that that was related to the cortical stimulation of an elevated pO2, as observed in the paper, rather than a "narcotic" effect?
"Hyperbaric oxygen seemed to disturb the time evolution of EEG patterns that could be taken as evidence of early oxygen-induced cortical hyperexcitability."

People trying to save money on gas while tech diving is wild to me. Tech diving is expensive, I wish it wasn't, but it is.

For the record, I don't raise the question in hopes of saving money on gas. Choosing my bottom gas on my JJ makes a few percent He either way a non-issue. Rather, I think it's a fascinating question as we try to calculate a meaningful END.
Me, I'll dive 25% He inside the Spiegel Grove at 110-130'. I hate even mild narcosis in the dark.

 

[john120283]

The narcotic properties of the specific gases used in a chosen gas mixture isn’t the factor that can have an impact on narcosis. Overall gas density also has an effect on the body’s ability to exchange CO2, which is extremely narcotic. So even if O2 isn’t narcotic, using an overly dense gas mixture can put you at a higher risk of narcosis issues as well as hypercapnia.

 

[jadairiii]

Interesting observation.
Is it possible that that was related to the cortical stimulation of an elevated pO2, as observed in the paper, rather than a "narcotic" effect?
"Hyperbaric oxygen seemed to disturb the time evolution of EEG patterns that could be taken as evidence of early oxygen-induced cortical hyperexcitability."

Say what?? Did you miss the fact that my "science" degree is in politics?