Nitrox: Narcosis myth?

[Steve_C]

I'm guessing that the two kegs were nearly indistinguishable in terms of content.
Löwenbräu - Wikipedia

In 1975,​

You underestimate my age. This keg was shipped up from New York on a special order and was from Germany. I was in New Hampshire at the time and the year was either 1965 or 1966. Some of my fraternity brothers had far more money than I had. The two beers did not taste the same to me.

 

[Patoux01]

Only when they said this is not lowenbrau did we give them one.

The best part of this, is that we consider it to be piss here around . At least, to put it this way, I spend my first 2 years of studies drinking that because "it's the cheapest you can get that is still drinkable" (and came in cans of 0.5l, so we could "just take one" ). So I hope for you the recipe changed since

 

[Steve_C]

My comparison was with 1965 Millers vs 1965 Lowenbrau. Not a high standard for Lowenbrau to beat. I have had some great beers while in Belgium and Germany, found that France even had some good beers once I learned how to order them, drank the original Budwieser Budvar in Czech when it was still a communist country. Have had good beers in a lot of places (Poland, Amsterdam, Greece, Italy, etc) but cannot recall having a great beer in Switzerland that was Swiss.

 

[Patoux01]

cannot recall having a great beer in Switzerland that was Swiss.

They weren't around yet I believe... We got a few of them : BFM, Nebuleuse, there's a few others that I forgot, and those are only the ones from around my city , surely there's some more a bit further away.

But we're drifting a bit far from the topic though

 

[Saniflush]

You underestimate my age. This keg was shipped up from New York on a special order and was from Germany. I was in New Hampshire at the time and the year was either 1965 or 1966. Some of my fraternity brothers had far more money than I had. The two beers did not taste the same to me.

Was your pledge name Flounder?

 

[stuartv]

My comparison was with 1965 Millers vs 1965 Lowenbrau. Not a high standard for Lowenbrau to beat. I have had some great beers while in Belgium and Germany, found that France even had some good beers once I learned how to order them, drank the original Budwieser Budvar in Czech when it was still a communist country. Have had good beers in a lot of places (Poland, Amsterdam, Greece, Italy, etc) but cannot recall having a great beer in Switzerland that was Swiss.

I've only had Samichlaus from Switzerland. I wouldn't drink more than one at a time, but I quite like it.

 

[northernone]

Did I stumble into the pub while narced? Someone pour me a round.

 

[Dr Simon Mitchell]

Hello,

To add to the mix, this has just been published.

Objective vs. Subjective Evaluation of Cognitive Performance During 0.4-MPa Dives Breathing Air or Nitrox. - PubMed - NCBI

On balance, I favour the argument that oxygen is less narcotic at the pressures we can safely breathe because there is a substantial gap between inspired and tissue PO2 due to metabolism in the tissues that matter for a narcotic effect. In contrast, the gap between inspired and tissue tensions of nitrogen in the brain is almost zero because the brain is a very fast tissue. Having said that the functional difference in narcotic effect is probably quite small. If we really want to avoid narcosis, then breathing helium is the key.

Simon M

 

[RayfromTX]

Am I right to believe that .4-MPa is approximately equal to 100 fsw. Is there anything else we need to consider in drawing conclusions from this study?

Is it correct to suggest from this study that narcosis is significant at 100 fsw? Is there a layman's equivalent impairment to alcohol impairment or is the narcotic effect more similar to the impairment of other sedative drugs. It seems most like the effects of the twilight anesthesia drugs. Where can I find these types of comparative studies or discussions?

 

[Dr Simon Mitchell]

Hi Ray,

Am I right to believe that .4-MPa is approximately equal to 100 fsw.

Yes.

Is it correct to suggest from this study that narcosis is significant at 100 fsw?

Actually, the remarkable thing about this study is that cognition (as measured by the tests they used) improved after 15 minutes at depth (in both air and nitrox arms but more in the nitrox arm) , and then deteriorated during the ascent and early after surfacing (but less in the nitrox arm). The potential explanations for this are complex and I would be happy to send you the paper if you PM me an email address (I should probably not upload it here because it is a very recent paper and I have no editorial role with the journal). The point in relation to the present discussion is that there is a difference between air and nitrox which favours nitrox.

I would caution against interpreting this study as suggesting that narcosis is not a problem at depth (because it clearly can be). These were dry dives in a hyperbaric chamber without concomitant task loading, and without provoking any tendency to retain CO2 at the same time. It is difficult to fathom what it all means for diving in the real world.

Simon M