Confused about Narcosis...

[boulderjohn]

A recent thread on narcosis and nitrox introduced information that surprised me. It seems that no one can say with any certainty what effect nitrox has on narcosis. The main problem is that it cannot be tested easily because of the dangers of elevated O2. We thus rely primarily on its properties and our theories on what causes narcosis. This leads to the next problem. We have no way of knowing for sure how much of an effect the fact that O2 is metabolized by the body has on that theoretical effect.

As a result....

There are those who believe with good reason that nitrox is more narcotic than air.

There are those who believe with good reason that nitrox just as narcotic as air.

There are those who believe with good reason that nitrox is less narcotic than air.

 

[Jim Lapenta]

Not to go off on a tangent, but I'd be more concerned about a DM taking a new diver to 138 feet, especially if said diver still has questions about narcosis. That displays an incredible lack of professional judgment on the DM's part.



Nobody fully understands what causes narcosis, and the current theory is that both oxygen and nitrogen -- or any gas for that matter -- have their own narcotic properties at depth (although we still usually refer to it as nitrogen narcosis since nitrogen is believed to be the primary contributor). At 138', you wouldn't have to worry about being narc'd on nitrox since you'd probably be in convulsions from oxygen toxicity. But nitrox is a separate issue with its own set of risk factors...I apologize from even bringing it up in my original post. It was a careless afterthought.

If diving the proper mix for that depth O2 toxicity would not be a big issue. 25% nitrox would be just fine. You could run that for 20 mimutes and still be below 1.4 ppo2. But heartily agree with piss poor judgement by the DM to the point of being reckless.

 

[paddler3d]

Divers can learn to cope with the effects of narcosis. Just like a substance abuser can learn to cope with the effects of their substance of choice and function. A functioning alcoholic comes to mind.

I've been narced in the past. I'm sure I'll get narced again.

What was surprising for me was I did not feel buzzed. I wouldn't describe it as the rapture of the blue or deep. It didn't feel good. If it did, I'm sure I'd been doing many more deep dives

I felt very anxious and rather paranoid. Once I've recognized these as my signs of being narced the anxiety has diminished. It is still there, but not as intense.

So far my magic number is below 125fsw. If I'm cold or other wise physically uncomfortable, it has been as shallow at 100fsw.

I've found that my key to management, or coping, is to conscientiously slow down, relax, think, focus.

As devondiver mentioned, stress yourself at depth (take safety precautions) and you can likely cause yourself to become narced. A lot of the agencies offer Deep Diver as part of their AOW. The point of most of the 2nd dives to get deep enough in a controlled situation with a more experienced diver and task load. Possible you'll experience narcosis.

When I did my deep cert, we went to 122ffw, 38F and I had to do my math problems, which were fine and switch to an alternate air source. I switched to my pony and low and behold my pony reg went into free flow. I had to manage that. Did I get narced? Who knows. Did I manage the situation? I did. Did I learn something? My MK25 is not a good cold water reg and I got another Apeks for my pony. Was I glad that I had an experienced instructor with me? Absolutely!

 

[MaxBottomtime]

I make a point of conducting an 'exertion test' also.

In deep water (30-40m), when there is no or slight narcosis felt, have the diver fin hard for a few minutes (until breathing hard). Then test again for narcosis.

The results can be surprising... and will teach how the onset of narcosis can drammatically be brought about in a demanding and/or emergency situation.

When I've been hit hard by CO2 narcisis it's been while moving the anchor at depths of 130+. A buddy told me once to stop, take two deep breaths and the feeling will go away. I didn't believe him, but it worked. Since then I have relaxed, taken a few deep breaths and was fine for the rest of the dive.

 

[captain]

On one ocasion I was diving under an oil rig in 400 feet of water. I was at 140 feet when I got the feeling that I was losing control of my buoyancy and sinking when my depth gauge showed that I was not decending but I could not shake the feeling of being drawn down.

I believe if I had been at 140 feet on a hard bottom I would not have had the same reaction to the narcosis. Going up to 100 feet completely eliminated the feeling.

 

[MXGratefulDiver]

Not to go off on a tangent, but I'd be more concerned about a DM taking a new diver to 138 feet, especially if said diver still has questions about narcosis. That displays an incredible lack of professional judgment on the DM's part.

To a degree, it depends on the environment and circumstances ... although in general I completely agree that it's not a good idea.

However, there's a big difference between 138 feet in a nice, warm, tropical location and one in a cold, dark environment. There's also a big difference in an environment where there's current and one where there's none at all.

Until I received my tech training, the deepest I had ever gone was 137 feet ... on a wall dive in Bali. At the time I had less than 50 dives. It was far less "threatening" than a lot of 100-foot dives I had done at home, and although I'm certain I was narc'ed silly, I didn't feel it. By contrast, I've felt more narc'ed at home at depths far less than that.

... Bob (Grateful Diver)

 

[rstofer]

Divers can learn to cope with the effects of narcosis. Just like a substance abuser can learn to cope with the effects of their substance of choice and function. A functioning alcoholic comes to mind.

As in drunk drivers? The functioning alcoholic believes they can still drive but statistics prove otherwise. I don't care if the alcoholic is involved in a one-car, one-person accident. Unfortunately, they seem to want to take others with them.

As a practical matter, narcosis in my buddy is not a problem. At least, it's not my problem as long as I can keep away from them. But there is no way in the world I'm going to allow myself to lose control of my abilities.

There is just no reason to take the risk. Keep it shallow or change gases.

Richard

 

[OnceLoyal]

I posted that dive in the accidents/incident forum.........So yeah, it was a stupid mistake on my part. I am upset with the DM, but imo the blame is on me. I, as everyone else had training on Narcosis. I know the basics, but just trying to research a little more. I am just thinking more and more about that particular dive. Trying to figure out how people justify diving so deep on air when they know damn well they are experiencing narcosis.

 

[TSandM]

Trying to figure out how people justify diving so deep on air when they know damn well they are experiencing narcosis.

Because they don't think they're impaired. Or they think they can "handle" it. And the training to use helium is involved and expensive, and the gas is expensive, and some places it's difficult to impossible to get. And they want to do the dives anyway.

If you want to read something chilling about the decision to do a deep, complex dive on air, read Shadow Divers or The Last Dive.

 

[OnceLoyal]

Because they don't think they're impaired. Or they think they can "handle" it. And the training to use helium is involved and expensive, and the gas is expensive, and some places it's difficult to impossible to get. And they want to do the dives anyway.

If you want to read something chilling about the decision to do a deep, complex dive on air, read Shadow Divers or The Last Dive.

If you want to read something chilling about the decision to do a deep, complex dive on air, read Shadow Divers or The Last Dive.[/QUOTE]

Funny you should say that. I am picking up Shadow Divers tonigth when I pick my tanks up from being filled Thanks