Nitrox: More, Less or Equally Narcotic as Air

[Cave Bum]

ANd when you switch to pure oxygen at 6 metres do you feel the narcotic hit?

I haven't noticed it with 32%, I'll let you know if it's different with air...

 

[Rhone Man]

So, is there anyone from Europe (or anywhere else) reading this that does indeed hold it as an article of faith that nitrox reduces narcosis? If so, what are the reasons?

Just to be clear - I don't have any European training - just relaying what I read in British diving magazines. Most recently I was reading a report on diving up at Scapa flow and the reviewer was saying that he was normally suffering from Narcosis on a particular wreck, but on this dive he was on EAN33 (or some other weird non-standard mix) and so his head was much clearer. I can scan the page of the article if anyone likes, but it is something I seem to see a lot the other side of the pond.

 

[Gene_Hobbs]

This does indeed support the idea that nitrox is less narcotic than air, but the degree that this is true is not at all clear. Or am I reading this wrong?

Or does it... There are two questions here.

How narcotic is oxygen? (It is not up for debate that it IS narcotic, rats go to sleep at 800 fsw on O2)
AND
(If we assume that O2 by itself IS less narcotic)
Is any advantage from the higher O2 in nitrox offset by the greater CO2 that is held by the body from that higher O2?(1) ('cause we all know how CO2 and N2 work together...)

The literature supports that oxygen is less narcotic... not that nitrox is less narcotic.

(1) Older post I made quoting Lanphier and Camporesi

...and to get you started on further reading (OK, really for your blog Steve... Let me know if you need the papers while you write... ):

Frankenhaeuser M Graff-Lonnevig V Hesser CM. 1960. Psychomotor performance in man as affected by high oxygen partial pressure (3 atmospheres) Acta Physiol Scand; 50:1-7 PubMed ID: 13701420

Frankenhaeuser M Graff-Lonnevig V Hesser CM. 1963. EFFECTS ON PSYCHO- MOTOR FUNCTIONS OF DIFFERENT NITROGEN-OXYGEN GAS MIXTURES AT INCREASED AMBIENT PRESSURES. Acta Physiol Scand; 59:400-9. PubMed ID: 14082611

Paton WDM (1967) Experiments on the convulsant and anesthetic properties of oxygen. Brit. J. Pharm. 29, 350-366. PubMed Central: PMC1557218

Thomas, JR. Combined effects of elevated pressures of nitrogen and oxygen on operant performance. Undersea Biomed Res. 1974 Dec;1(4):363-70. RRR ID: 2677

 

[boulderjohn]

...and for another point of view:

Diving Doctor - Diver Magazine

 

[Steve SDI/TDI HQ]

...and for another point of view:

Diving Doctor - Diver Magazine

David is a fine scientist... not a bad cave explorer either :cool2: and I'm inclined to agree with him on this one... the body of evidence is inconclusive and the parameters used to measure the narcotic loading of gases deal with gases that have a very different general behavior to oxygen.

 

[DiveNav]

I don't mean to hijack the thread .... but ... any idea on how we could simulate the effects of N2 and O2 narcosis?

Right now, when the virtual diver is being hit, we just black out the screen and write a message (you are going to die of ..... your dive will not be counted), but it will be nice to have some visual effect for those 2 types of narcosis.

Thanks

Alberto

 

[Blackwood]

^^ You mean on eDiving.us?

I don't know... narcosis hits everyone differently, and varies from time to time.

I, personally, have never had the fabled talking to the fishes giddy narcosis, nor have I had the holy crap I'm going to die 'dark-narc.' For me, I usually recognize it as a lack of focus and poor attention: no idea what my gauges say 30 seconds or a minute after looking at them; inability to hold to a compass heading, etc..

 

[boulderjohn]

I, personally, have never had the fabled talking to the fishes giddy narcosis, nor have I had the holy crap I'm going to die 'dark-narc.' For me, I usually recognize it as a lack of focus and poor attention: no idea what my gauges say 30 seconds or a minute after looking at them; inability to hold to a compass heading, etc..

Same here. I have never felt any kind of impairment, and I would probably swear I had never been affected at all if I had not seen tangible results:

• Swimming through a hole in the wall of a wreck after I saw my buddy snag his regulator hose on a small piece of pipe and then slide it down to free it, I snagged my hose on the same pipe and asked myself "Which hose have I snagged? How do I free it?"
• I was playing with the adjustment on my regulator to solve a minor free flow when my buddy signaled me and asked why I was breathing off my alternate. I had no idea until then that I was.

 

[DiveNav]

^^ You mean on eDiving.us?.

YES, in our simulator

...I, personally, have never had the fabled talking to the fishes giddy narcosis, nor have I had the holy crap I'm going to die 'dark-narc.' For me, I usually recognize it as a lack of focus and poor attention: no idea what my gauges say 30 seconds or a minute after looking at them; inability to hold to a compass heading, etc..

Thanks.

For the N2, what about simulating being drunk?
We could create a visual effect where images are being duplicated ...
When you start to "see doubles" then your PPN2 is a bit high and you should ascend.

AM