Alarming and Dangerous Incident please read

[JEScholz]

What is the actual point of this argument? With either EAN21 or EAN32 at 100 fsw you've got basically the same amount of N2 in your gas and I know I've turned dives at 90 fsw on EAN32 because I got a severe narc hit on that particular day. Diving 30/30 or 21/35 is totally different and you can argue about if its the reduction of N2 or the addition of He, but its all kind of moot -- you can't dive EAN60 to 100 fsw (same nitrogen as 30/30 only no helium) because you'll tox and die. I'll take the helium mix over the nitrox...

Lamont, Please help me to understand how you end up with the same amount of N2 in your tank when you have the same volume, same pressure and 11% more O2? Doesn't that reduce your N2 by 11%?

 

[BHB ScubaTroll]

Ok, I've read most of the posts...

If someone on the surface were to act as though they were not getting enough 02, most people would treat for:

Hyperventilation - condition where an individual breathes too rapidly and has a lowered CO2, lowered Ca++ with the production of tetany; usually due to panic

As stated ealier.

Based on the explanation, it appears this diver was experiencing hyperventilation and a rapid ascent depleted the PPO and volume to a level that would be expected if the diver were on the surface breathing in and out of a bag.

The only difference is that he was breathing from a self contained tank with additional stress and panic based on being underwater.

It sounds logical to me.

 

[uspap]

I'm curious. What does it feel like to be narced? I've been past 100 feet on more than one occasion and can't say I've felt much diffrence. Hypotheticaly, if a person had a high tolerance for alchool would that make him better equiped to deal with nitrogen narcosis? Pardon my ignorence. (and bad spelling)

 

[Thalassamania]

While the relief of symptoms on ascent make narcosis a reasonable first guess, the severity of your symptoms with an EAD of only 55 feet argues rather stongly against that explaination.

 

[GDI]

One of the things to consider here is that all divers are different. The complex exchange of gases going on in the human body during a dive when added to the external factors such as rest, cold, phyiscal conditioning and the actual dive factors such as rate of descent, equipment performance and technique/skill.

Inert Gas Narcosis will occur at different times and pressures for different gases for each diver, a diver's personal tolerances play into this under variable conditions from one day to the next.

For this matter why do we call it Inert Gas Narcosis when in fact there is nothing Inert about diving and different gases? O2's narcosis properties are the lessor concern to it's toxic factors. I submit this link for discussion

http://www.divermag.com/archives/dec96/divedoctor_Dec96.html

 

[Thalassamania]

One of the things to consider here is that all divers are different. The complex exchange of gases going on in the human body during a dive when added to the external factors such as rest, cold, phyiscal conditioning and the actual dive factors such as rate of descent, equipment performance and technique/skill.

Inert Gas Narcosis will occur at different times and pressures for different gases for each diver, a diver's personal tolerances play into this under variable conditions from one day to the next.

Sure, but in my experience, the kind of reaction the diver had at and EAD of 55 (or 70 for that matter) is way beyond anything I've experienced or heard of anyone else experiencing. Of course, he may be an extreme outlier, but it's a tautology to say that that's unlikely.

 

[BarryNL]

I was diving the Tracy in about 75 ft of water off the coast of Ft.Lauderdale, Florida. I had two diving buddies. When we reached the wreck, conditions were good, not great - 40 ft visibility, light current. I was on Nitrox at 36% which was checked at the shop. Upon reaching the wreck I began to expirience a shortness of what seemed oxygen in the mix. I was getting all the volume I demanded of my regulator (Scubapro S600) yet felt like it was not oxygen. Confused I swam towards one of my two buddies which turned into a dash due to the increase deficiency of oxygen. Despite the standard signals I gave him for difficult breathing all I got was a spaced out look from him. Oblivious to what was unfolding right in front of his eyes. At this point I pointed straight up with my hand and bolted up in a semi "controlled panic". I knew that something was deadly wrong, I knew I needed to breath and I needed to reach the surface. I also know that my chances for survival would be in my favor risking the bends or embolism to reach the surface. I was leterally sufficating. At about 30 ft from the surface immediately I started to feel like the oxygen was returned and quickly returned to normal. I went back dowm to find the two individuals diving with me to let them know I was OK and to do a proper gassing off ascent. It seems like I was sucking on nitrogen. Can the gasses separate or layer off in the tanks? I know for a fact that the shop owner does not roll tanks to get proper mix as did the previous owner. Any suggestions, recommendations are deeply appreciated.

Peter

I doubt your feeling of "no oxygen" was correct, for two reasons. Firstly, the breathing reflex is caused by CO2 buildup, so it's high levels of CO2 which cause a suffocating sensation; indeed, rebreather users who forget to switch on their oxygen tend go unconscious before noticing there is anything wrong. In fact, this is also the second reason - if the oxygen was really too low you would be unconscious before you noticed a problem.

Actually, there's a third reason: your O2 partial pressure will be higher at depth so if the tank was giving a low O2% the problem would actually get worse as you ascended.

So, I don't know what the problem was, but it wasn't a low O2 %.

 

[*Floater*]

I'm curious. What does it feel like to be narced? I've been past 100 feet on more than one occasion and can't say I've felt much difference. Hypothetically, if a person had a high tolerance for alcohol would that make him better equipped to deal with nitrogen narcosis? Pardon my ignorance. (and bad spelling)

According to my tech instructor the answer is yes (though I'm not sure if that was based on anything scientific). People with high tolerance to alcohol tend to have high tolerance to narcosis as well, though there are many contributing factors and everyone is affected by it to some extent even though they may not feel it.

Also, one of the leading researchers in the field (I forgot which one, maybe Bennett) said on GUE's Mysterious Malady DVD that according to some experiments people tend to act the same way under narcosis as they do when drunk. So the belligerent drunk is belligerent when narced, the confused drunk is confused when narced, and the drunk who wakes up with the ugly chick.... well, you get the idea.

 

[Thalassamania]

According to my tech instructor the answer is yes (though I'm not sure if that was based on anything scientific). People with high tolerance to alcohol tend to have high tolerance to narcosis as well, though there are many contributing factors and everyone is affected by it to some extent even though they may not feel it.

Also, one of the leading researchers in the field (I forgot which one, maybe Bennett) said on GUE's Mysterious Malady DVD that according to some experiments people tend to act the same way under narcosis as they do when drunk. So the belligerent drunk is belligerent when narced, the confused drunk is confused when narced, and the drunk who wakes up with the ugly chick.... well, you get the idea.

I've heard the same thing but, at least in my case, it's not so. I can deal with significant depth (in water and chamber) without much effect, but I'm a candy-*** when it comes to alcohol ... two drinks and I will not even try to drive.

 

[uspap]

So is Narcosis more like having a buzz or being fried? or does it just depend? For me 2 drinks doesn't do much. I do not drive after 2 drinks though. Not that I couldn't. It's not worth the risk.
I'm asking this because it sounds liked getting Narced can be severe. I want to know what to expect so I can identify it when it happens and avoid doing something stupid.
I have felt moderately more nervous past 100 feet before but not paranoid. Could that have been part Narcosis?