Narcosis Properties of Different Gases

[gianaameri]

The cave is a very different and unique environment and it would be imprudent to apply the generic 100' to 120' END training agency recommendations.

More experienced cave divers and cave specific textbooks indicate an END below 100'

It would also be imprudent to use air instead of N32 for cave dives up to 100' (as equally it would be imprudent not to treat O2 as narcotic for Trimix dives below 100').


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[Dr. Lecter]

The cave is a very different and unique environment and it would be imprudent to apply the generic 100' to 120' END training agency recommendations.

You have failed to provide any agency or other authority to support this claim of yours. Put up, or shut up.

More experienced cave divers and cave specific textbooks indicate an END below 100'

We're waiting for you to do something other than talk in generalities. List some.

It would also be imprudent to use air instead of N32 for cave dives up to 100' (as equally it would be imprudent not to treat O2 as narcotic for Trimix dives below 100').

Let me get this straight: you think EAN32 is better than air because it's less narcotic...but then you admit that not treating O2 as narcotic is also imprudent. Does the presence of He somehow magically enhance the narcotic effects of O2? Get this through your head: the only scientific evidence of which anyone seems to be aware shows that at any given depth, you are just as narced on EAN as you are on regular old 21/00. If you think adding an extra 10% O2 to the mix somehow meaningfully reduces narcosis at 100', by all means, show us some evidence.

Not to stray away from topic,

Too late.

 

[gianaameri]

You have failed to provide any agency or other authority to support this claim of yours. Put up, or shut up.



We're waiting for you to do something other than talk in generalities. List some.



Let me get this straight: you think EAN32 is better than air because it's less narcotic...but then you admit that not treating O2 as narcotic is also imprudent. Does the presence of He somehow magically enhance the narcotic effects of O2? Get this through your head: the only scientific evidence of which anyone seems to be aware shows that at any given depth, you are just as narced on EAN as you are on regular old 21/00. If you think adding an extra 10% O2 to the mix somehow meaningfully reduces narcosis at 100', by all means, show us some evidence.



Too late.

I can answer all/most of your questions (later this afternoon), but I suggest you start a different topic or the Mods. split the thread so that the issue of O2 and Narcosis in a cave environment and textbooks and pros. and cons... we discuss in a specific thread.

 

[PfcAJ]

"...nitrogen narcosis is diminished" but o2 narcosis is increased.

I find your lack of evidence disturbing.

 

[gianaameri]

"...nitrogen narcosis is diminished" but o2 narcosis is increased.

I find your lack of evidence disturbing.

There just is no evidence that O2 is narcotic at recreational diving depths.

Millions of dry dives in a chamber must have been done in 100% O2 at 18 meters - no narcosis whatsoever reported (just go and try one such dive yourself).

All research I have seen to date has been done to conditions exceeding recreational depths/mixes/exposures.

For example, "A rise in O2 pressure to 1.65 ATA, or in N2 pressure to 6.3 ATA at a constant high PO2 level, caused a significant decrement of 10% in mental function but no consistent effect on psychomotor function (see Roles of nitrogen, oxygen, and carbon di... [Undersea Biomed Res. 1978] - PubMed - NCBI ).

I may very well be wrong, and would very much appreciate any hyperbaric specialist chiming in on the subject with the very latest thinking/research!

 

[syntaxerrorsix]

You really think Nitrox is less narcotic than air don't you?

 

[syntaxerrorsix]

"It thus seems that substituting O2 for some of the N2 does not ameliorate the mild narcosis."
[abstract] DOES OXYGEN CONTRIBUTE TO THE NARCOTIC ACTION OF HYPERBARIC AIR?

"The results suggest that, at raised partial pressures, all three gases have narcotic properties, and that the mechanism of CO2 narcosis differs fundamentally from that of N2 and O2 narcosis."
Roles of nitrogen, oxygen, and carbon dioxide in compressed-air narcosis

---------- Post added August 27th, 2013 at 04:25 PM ----------

"Breathing Nitrox is not thought to reduce the effects of narcosis, as oxygen seems to have equally narcotic properties under pressure as nitrogen, thus one should not expect a reduction in narcotic effects due only to the use of Nitrox. Nonetheless, there remains a body of the diving community that insists that they feel reduced narcotic effects at depths breathing Nitrox. This most likely is a placebo effect and may be due to a dissociation of the subjective and behavioral effects of narcosis."

Information on Scuba Diving with Nitrox

From the DAN workshop link to .pdf

https://www.google.com/url?sa=t&rct...=jnRcmE4ZfNnuNX35GfGIgA&bvm=bv.51156542,d.cWc


"Narcosis
Another physiological effect of air or enriched-air mixtures is inert gas or nitrogen narcosis.
Narcosis is not an important issue in enriched air diving because the depths where these mixes
are efficient are too shallow to invoke serious narcosis in most divers. Even so, a claim made by
some proponents of "nitrox" is that it reduces narcosis. There is no objective evidence that this
is the case. It is not likely because the properties of oxygen suggest that this gas should be even
more narcotic than nitrogen, and limited experimental work supports this idea (Bennett, 1970;
Linnarsson et al, 1990)."

 

[gianaameri]

"It thus seems that substituting O2 for some of the N2 does not ameliorate the mild narcosis."
[abstract] DOES OXYGEN CONTRIBUTE TO THE NARCOTIC ACTION OF HYPERBARIC AIR?

"The results suggest that, at raised partial pressures, all three gases have narcotic properties, and that the mechanism of CO2 narcosis differs fundamentally from that of N2 and O2 narcosis."
Roles of nitrogen, oxygen, and carbon dioxide in compressed-air narcosis

---------- Post added August 27th, 2013 at 04:25 PM ----------

"Breathing Nitrox is not thought to reduce the effects of narcosis, as oxygen seems to have equally narcotic properties under pressure as nitrogen, thus one should not expect a reduction in narcotic effects due only to the use of Nitrox. Nonetheless, there remains a body of the diving community that insists that they feel reduced narcotic effects at depths breathing Nitrox. This most likely is a placebo effect and may be due to a dissociation of the subjective and behavioral effects of narcosis."

Information on Scuba Diving with Nitrox

If you look at all those studies, they are done outside of recreational diving depths and typical recreational diving exposures.

 

[PfcAJ]

There just is no evidence that O2 is narcotic at recreational diving depths.

Millions of dry dives in a chamber must have been done in 100% O2 at 18 meters - no narcosis whatsoever reported (just go and try one such dive yourself).

All research I have seen to date has been done to conditions exceeding recreational depths/mixes/exposures.

For example, "A rise in O2 pressure to 1.65 ATA, or in N2 pressure to 6.3 ATA at a constant high PO2 level, caused a significant decrement of 10% in mental function but no consistent effect on psychomotor function (see Roles of nitrogen, oxygen, and carbon di... [Undersea Biomed Res. 1978] - PubMed - NCBI ).

I may very well be wrong, and would very much appreciate any hyperbaric specialist chiming in on the subject with the very latest thinking/research!

The very next line of that abstract read " The results suggest that, at raised partial pressures, all three gases have narcotic properties, and that the mechanism of CO2 narcosis differs fundamentally from that of N2 and O2 narcosis."Most divers do not subjectively report any narcosis at all at 18m while breathing air, nitrox, or in your example, o2. Self assessment is a notoriously poor gauge of narcosis, and we know from studies that people are in fact affect by narcosis at virtually all depths to some degree.

Please explain a mechanism for why o2 would suddenly become narcotic beyond recreational depths (an arbitrary line) but isn't when shallower? Please provide evidence to support this (the plural of anecdote is not data, btw). Please provide an explanation for why adjusting the fO2 and fN2 provides the same narcotic response in the above study? Explain why ALL major scuba organizations and government agencies accept the narcotic potential of oxygen.

You're just not well read on the subject, you fail to produce any evidence at your claims, your and anecdotes are all based on self assessment. Here in the land of science, that just doesn't cut it.

 

[nimoh]

If you look at all those studies, they are done outside of recreational diving depths and typical recreational diving exposures.

maybe you should read them again?