Nitrogen Narcosis.

[Tekk Diver]

Everyone get's narc'd...at some point, Yes.
But not everyone notices it.

When I begin to notice the subtle beginning effects of nitrogen narcosis, I don't immediately abort the dive, or get shallower.

I haven't been narc'd to a point where I thought to myself: This is unsafe... I'm not safely in control of my mind or my actions at this depth.

You should be able to tell when your reasoning and judgement becomes impaired to an unsafe degree.. by simple "narc tests" you learn while out diving or training.

When YOU (or your buddy), reach a level of impairment that you cannot safely continue your dive... you should seriously reconsider your depth or maybe a different breathing gas.

Some can drive a car safely only having one or two beers. After one or two beers, some don't even know how to unlock the car door.
Some can dive safely to 130ft, after feeling narcosis since 100ft. Although, your buddy might begin to feel narcosis at 100ft and be completely unable to safely continue to 130ft.

 

[Boogie711]

It's not about 'feeling' narc'd. Feeling narc'd means jack-all. It's about being narc'd. You can be just as impaired and not feel it, because one of the symptoms of narcosis is NOT FEELING NARC'D!

Some can drive a car safely only having one or two beers. After one or two beers, some don't even know how to unlock the car door.

Correction - some FEEL they can drive safely home. That doesn't mean they can.

Saying that you're safe to dive until you feel the effects is living in denial. Are you going to tell us you advocate deep air "training" as well?

 

[DeepTechScuba]

Besides neutral gravity due to perfect buoyancy floating underwater, the reason everyone diving feels so good is because mild tranquilizing narcosis happens almost immediately. I feel happily narked even at 15 ffw in the pool while freediving!

I relax. I feel happy. Even my fiancee notices that I am happy when I go into the water, at any depth.

At 50 fsw you should be able to notice at least a subtle tranquilizing effect.

At 110 fsw I notice that the EAN32 begins to have a martini effect. Thats when I begin to feel the two-martini buzz.

At 150 fsw on EAN25 the buzz begins to be impairment, and there is also an I-dont-care-too-much attitude, so I have to force myself to follow protocols. This is a technical depth, by the way, so dont try this without technical gear and technical training.

At 170 fsw on Air21 I notice that a paranoia begins to set in. Even though all systems are go, and I have complete redundancy of gear and of gasses. Even though there is nothing to fear, I notice the paranoia sensation.

NOAA's limit for pre-trimix diving is 170 fsw, with the lower 150 fsw recommended instead of 170 fsw. Other agencies such as GUE use 100 fsw as their pre-trimix limit.

Anything deeper than 100 fsw is probably a technical depth. And diving between 50 fsw and 100 fsw are probably nitrox depths, for safety's sake. There is no good reason to breath air between 50 and 100 fsw and subject yourself to the N2 loading of air needlessly.

With easy modern access to trimix and trimix training, there is probably no good reason to dive deeper than 150 fsw without trimix. And some technical agencies feel that 100 fsw is the proper cutoff to begin trimix.

Since helium and neon are significantly less narcotic than nitrogen, gas mixes containing less nitrogen will have a lower Equivalent Narcotic Depth.

But there is still mild narcosis at any depth.

 

[CD_in_Chitown]

Tekk Diver once bubbled...
Everyone get's narc'd...at some point, Yes.
But not everyone notices it.

Exactly. There's two types of divers, those who admit to feeling narced and those who lie about it.

It's exactly the same as asking a drunk person whether or not he is drunk. Just because they don't realize they're drunk doesn't mean they're not.

Many drunk persons are aware they are drunk and choose not to partake in risky activities that require motor skills, I don't think any dui arrestee doesn't realize the impairment to some extent. And knowing full well that impaired judgement accompanies the physical impairment these folks chose to drive anyway, justifying in some way their actions. How bad does narcosis have to be before you thumb the dive? That's the decision that you and your buddy have to be able to make. That neither of us can make the call doesn't fly, someone has to make the call and there isn't anyone but us there.

It's inevitable that you will be narced to some extent at depths below 50fsw. The trick is that the impairment will not be uniform in the progression, or consistent in the depth where manifestation is noted. I have been to 130-140 and felt that warm buzz that makes me think Maybe I'm pushing my luck, and I've been totally freaked out at 115 and desperate to ascend, thumb it and play around in shallower water. I don't know if it's not enough food before a dive, lack of some nutrient, hydration, etc. I try to stay well hydrated and still eat something before a dive, but even science hasn't determined what and how narcosis is affected in divers. Every diver is affected in different ways, and every dive is somewhat different for each diver. I know the physical feelings of narcosis set in somewhere around 100fsw, but if it stays peripheral and comfortable I'll push deeper. If I get uncomfortable I'm aware what is causing it and that ascent to <100fsw will solve it. Don't dive air at those depths usually, but it's more to bring focus to the activity.

 

[Kendall Raine]

I've felt fine on air dives to 150-170. I've felt impaired on nitrox dives to 100. It depends. Was I "narc'd" on both dives? Yes.

Physicians are well aware of the strong correlation between the narcotic properties of a gas and its lipid solubility. This suggests narcosis is a physiological rather than simply psychological effect. Nitrogen is much more soluble in lipid than helium. Oxygen is more lipid soluble, still. Carbon Dioxide beats all three-by much more even than its relative lipid solubility would suggest. The physiology of narcosis may not correlate very well with the psychological perception of the event.

Put another way, why can the same person feel narc'd at 100 feet one day and be completely lucid at 100 the next? Why does the narc tend to hit harder and shallower in cold dark water than in clear warm water? In my own experience, increased stress tends to correlate with greater narcosis at a given pressure. One's perception of the impairment can change dramatically depending on circumstances.

Which is more dangerous, the person who knows they're impaired or the person who is but doesn't know it?

The really insidious thing about narcosis is the impairment without realization. I once shot some video on an air dive to 175. During the dive I felt fine. It was only after seeing the video did I realize I was really impaired. On an air dive in cold dark water to 220, I knew I was stoned to the bone and felt completely paranoid. This is one reason I think the most dangerous zone for air diving is the 120 to 200 range where you can still think you're fully in control. Until you're not.

You can feel fine on a clear warm water dive to 150 until an external stress event occurs. All of a sudden, events happen faster than you can think. Your resperation goes up and your CO2 goes up. CO2 further drives up your impairment. A spiral has started on what was seconds ago a nice mellow dive. Narcosis is like toothpaste. It's really hard to put back in the tube once it comes out. The only solution once that happens is ascent, sometimes by a lot.

Alternatively, you can avoid the problem by not diving deep on air, or nitrox, in the first place.

For any dive deeper that about 100, I'll put helium in my mix. I know people who use helium shallower than that.

 

[DeepTechScuba]

Kendall, could you please speak to the notion that a shallow dive (my definition is less than 150 ft) with helium in your mix requires a stop (or several) on the way back to the surface, no matter how short (even only 5 mins) the duration of your dive?

Does any dive on helium mean that you cannot ascend directly to the surface?

I have absolutely no experience with shallow helium diving.

So as long as this subject has come up, can you clarify it please?

 

[ScottyK]

From Scuba Diving Explained, by Lawrence Martin MD.

"For some divers narcosis begins to manifest in the 80-130 fsw range, for others much deeper."

Denial??? I think some of you are confusing narcosis and alcoholism

Are your tissues loading with nitrogen at depth? Yes, absolutely.

Is narcosis an incompletely understood phenomenon that affects some divers much less than others? Also, yes.

 

[Tekk Diver]

Boogie711 once bubbled...
It's not about 'feeling' narc'd. Feeling narc'd means jack-all. It's about being narc'd. You can be just as impaired and not feel it, because one of the symptoms of narcosis is NOT FEELING NARC'D!



Correction - some FEEL they can drive safely home. That doesn't mean they can.

Saying that you're safe to dive until you feel the effects is living in denial. Are you going to tell us you advocate deep air "training" as well?

According to you..Boogie711...when you are narc'd, you are unfit to dive..because you are too "impaired" to safely continue diving because your reasoning and judgement abilities are gone due to narcosis.
So, you are saying I can be narc'd out of my mind, and not even realize it, because that is what narcosis does? Hmm. Interesting theory.
YOU may not realize when YOU have lost your mind, and have become too impaired for diving or driving.. in your case..
But, speak for yourself on those statements.

What I'm trying to say is: Yes, being narc'd is inevitable at certain depths. But, being able to handle the many levels of of nitrogen narcosis impairment...is completely up to the diver's physiology and state of mind. Your body can deal with more or less nitrogen...given certain variables are met.
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Ok. Yea. I have alcohol in my system...I'm slightly intoxicated. But my vision is normal. My speech is fine. I can even walk a straight line blind-folded. Just because alcohol is in my system, doesn't mean it affects me enough to make me an unsafe driver.

Same with narcosis.

Yea. Nitrogen is in my system...I'm slightly narc'd.. Feelin' kind of good..mellow. My vision is normal. I can add, subtract, multiply, divide...i'm a little slower at it, but my answers are still correct. I know how deep I am. I still know my dive plan - and I'm still diving my plan.

How is that being in denial?

 

[Tekk Diver]

"You can be just as impaired and not feel it, because one of the symptoms of narcosis is NOT FEELING NARC'D!"

One of the MANY symptoms might be "not feeling narc'd".. But what about all the others you can take note of, that might clue you in as to your level of narcosis.

Symptoms of nitrogen narcosis include: wooziness; giddiness; euphoria; disorientation; loss of balance; loss of manual dexterity; slowing of reaction time; fixation of ideas; and impairment of complex reasoning.

Boogie, you seem to think a person can't and won't realize any of these symptoms, because they are narc'd..

Not knowing your narc'd... more than likely occurs in the latter stages of severe narcosis...when you are stoned out of your mind.. But.. by then.. you should've noticed the convoy of other symptoms affecting you, and ascended. Thus, avoiding serious impairment.

 

[Big-t-2538]

Tekk Diver once bubbled...

Yea. Nitrogen is in my system...I'm slightly narc'd.. Feelin' kind of good..mellow. My vision is normal. I can add, subtract, multiply, divide...i'm a little slower at it, but my answers are still correct. I know how deep I am. I still know my dive plan - and I'm still diving my plan.

How is that being in denial?

It's not denial or being Narc's, but it is the ability to reason and problem solve something new....you can't "think on your feet" when your narc'd. Yeah, I can do anything I have trained myself to do when Narc'd....or even drunk. However, it takes me longer. Here's an example.

Let's say I had a free flow at 130 feet....I'm diving air...I'm Narc'd. It is going to take me longer to A. realize there's a problem. It is going to take me B. Longer to react to the problem...and C. Longer to solve the problem. WHAM...I'm OOA and now I have to signal to my buddy who is in the same situation of slower reaction times.....It just isn't safe or smart.

Correlation.....
The same holds true for a drunk driver. Yes, he will recognize that he is going to hit the telephone pole....but he can't react to it in time. Same thing...WHAM...end of story.