Narc vs dark narc?

[Pinecube]

I appologize if this has been answered elsewhere, I've done a quick search on the forums and turned up nothing (and less than nothing doing a google search...)

I've been reading through a lot of the accidents & near-misses stories and every so often I run across a mention of 'dark narc'. I understand narcosis and what being narc'd means, but I'm really just guessing at what they mean by dark narc. Anyone able to help me out?

 

[fisheater]

Narcosis is often described in terms of alcohol use. Sometimes you have a pleasant buzz. Sometimes, it's ugly. Thus, a "dark narc" is when, instead of feeling giddy and carefree, you feel an ominous dread.


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[Kevrumbo]

Link to an example of the Dark Narc (and the related condition of CO2 Retention which can induce it):
http://www.scubaboard.com/forums/near-misses-lessons-learned/110542-what-your-take.html

Deep Air with increased Gas Density & Work-of-Breathing; then throw in Physical Exertion or a Stress Condition, resulting in overbreathing the regulator (also can result from breathing a malfunctioning "wet regulator") --all leading to the Vicious Cycle of CO2 Retention and sudden Narcosis. Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . .

Taken from Undersea Biomedical Research, Vol 5, No. 4 December 1978 Hesser, Fagraeus, and Adolfson:

Studies on the narcotic action of various gases have shown that the ratio of narcotic or anesthetic potency of CO2 and N20 approximates 4:1, and that of N2O and N2 30:1. From these figures it can be calculated that CO2 has at least 120 times the narcotic potency of nitrogen. Our data would suggest that the narcotic potency of CO2 is even greater, i.e., several hundred times as great as that of nitrogen." (emphasis added).

 

[Stoo]

Fisheater and Kevrumbo sum it up nicely... I think of a dark narc as going hand in hand with getting out of ones "comfort zone". Since it isn't really anything "official" you won't find anything about it in the published medical literature. It's my opinion that there are a number of factors that can bring on a dark narc, and these include the water conditions (visibility, light, even temperature) and perhaps equipment that isn't behaving just right... A neck seal that's too tight, a little over-weighted or any number of little things that just put you off your "A-game".

I can dive a certain location to say 150' and 99 times out of 100, that dive will be great, but every now and again, I just want out of there... usually for some inexplicable reason. And I heed that feeling...

 

[Pinecube]

That makes sense, thanks guys!

 

[Nemrod]

Nitrogen narcosis is the resulting physiological condition of nitrogen under pressure having an anesthetic effect on the diver and altering the state of consciousness. It has nothing to do with ambient lighting.

N

 

[Kevrumbo]

The most important tip when you feel it coming on is to first establish neutral buoyancy, relax and try to regain a nominal breathing rate for a minute or two. Then begin a controlled safe ascent rate to shallower depths as needed until the dark narc subsides --or else go to your safety stop and abort the dive entirely.

 

[Dive Right In Scuba 2]

I once overheard an instructor describe narc/dark narc as the difference between a happy drunk and an angry/depressed drunk.

 

[j2s]

Fisheater and Kevrumbo sum it up nicely... I think of a dark narc as going hand in hand with getting out of ones "comfort zone". Since it isn't really anything "official" you won't find anything about it in the published medical literature. It's my opinion that there are a number of factors that can bring on a dark narc, and these include the water conditions (visibility, light, even temperature) and perhaps equipment that isn't behaving just right... A neck seal that's too tight, a little over-weighted or any number of little things that just put you off your "A-game".

I can dive a certain location to say 150' and 99 times out of 100, that dive will be great, but every now and again, I just want out of there... usually for some inexplicable reason. And I heed that feeling...

Ditto........It's that 'little' voice, deep in our sub conscience that we should always pay attention to !!......

 

[LeadTurn_SD]

Narcosis is often described in terms of alcohol use. Sometimes you have a pleasant buzz. Sometimes, it's ugly. Thus, a "dark narc" is when, instead of feeling giddy and carefree, you feel an ominous dread.

Garden Variety Narc = "Good Trip".

Dark Narc = "Bad Trip".

If you are not a child of the '70's, those examples probably do not make sense, so substitute "Happy Beer Buzz" for the usual narc, and paranoia, dread and impending sense of doom for dark narc.

I know which one is less pleasant, but I'm not sure which is really "worse"... When happily buzzed I'm likely to continue on my merry way, and may be getting into actual danger without "caring" enough about it; with a dark nark my immediate instinct is self-preservation and an ascent away from the feeling of "imaginary danger".

Best wishes.