Narcosis -- insidious and subtle

[Kevrumbo]

30/30 trimix diving aside (remember this is the Basic Scuba Discussion Forum):

The lesson for the novice basic open water scuba diver is to recognize the beginning of the effects of Nitrogen Narcosis, and to start ascending to a shallower depth as needed to "clear your head". Aborting the dive and slowly ascending to your safety stop is always your most prudent option. . .,

The following example is what can happen to a diver making bad decisions under the effects, and the transforming of confusing cognitive impairment to behavioral affects, of Nitrogen Narcosis:

http://www.scubaboard.com/forums/near-misses-lessons-learned/264517-type-i-bends-hit-chuuk.html

 

[ronbeau]

that's why god invented 30/30

At a risk of feeling naive, what is 30/30?
I know DUI has a 30/30 tropical dry suit but that appears to have no relevance to your statement.

 

[Jax]

At a risk of feeling naive, what is 30/30?
I know DUI has a 30/30 tropical dry suit but that appears to have no relevance to your statement.

Trimix is a gas used by technical divers. It is oxygen, helium, and nitrogen. When they give the x / y, that is the oxygen and helium percentages, and the "left out" nitrogen percentage is 100% - x% - y%.

There are a lot of issues diving trimix - do not attempt to do so without proper training!

 

[Eric Sedletzky]

I was doing a dive once up on the North Coast, very cold water, limited vis, etc.
We had to get up at 4:30 AM to get up to the coast where we were going to dive. I didn't sleep well that night as sometimes I don't just from the anticipation of the next day of diving.
We dove off shore on a seamount and we were cruising a wall at about 70 feet. I saw a fish I wanted so I speared it. After I put it on the game hook I tried to get my spear gun set up again and for the life of me I couldn't figure out how to do anything past putting the spear shaft back on the stock. I couldn't figure out how to wind up the line and get it set up, even though I've done this thousands of times my mind just drew a blank. That was only at 70 feet.

The other one is harvesting scallops deep past 100 feet. Divers on air can get really transfixed on the task and get very zeroed in on just what they're doing and forget all about times, depths, and air supply.
You have to really watch it.

Trimix where I dive isn't practical. There are no places to get fills and doing it myself is more trouble than it's worth plus it can be cost prohibitive.
I stick to being very careful with depth, making sure I feel good and get a good night sleep, and keeping the alcohol intake minimal or none the night before any diving.

 

[drdaddy]

Thank you, Andy!

My whole point in posting this (which is embarrassing and distressing to me) is to point out that you don't FEEL narced when you are. By the time you feel drunk or off kilter, you are so far beyond impaired that it's frightening. The first signs are failure to perceive important pieces of data, and making bad decisions. So many people post here and say, "I've never been narced!" The manifestations are way too subtle to be recognized, a lot of the time.

And yes, 30/30 is now my Florida gas. Florida trips just got much more expensive.

Thank you so much for this. I know that I was narced when diving Hood Canal looking at the sea whips and then descending to 114 feet. My Instructor son had warned me to expect it - and there it was - I felt "narced".

However, when diving with my son in the Red Sea to 120+ on a wreck dive in the Red Sea - I never felt narced. But I'm sure I was as I very seldom go below 80 to 90 feet on any of my dives.

I'm a psychologist and know that one's anticipation of something can influence how that something is felt. Something physiologically is going to happen to a person when the subject is given an IV shot of adrenaline - but the pre-event psychological condition (anticipation) influences the subjective experience.

I'm sure that water temperature (objective) and clarity (subjective) as well as just the fun (subjective) happening topside influences what's experienced down below.

I don't intend to do an analysis of your dive, but just to say the following. You felt safe diving with your husband on a "safe" (if there is such thing on any dive, let alone a cave dive) predictable dive and were having fun and did not feel any particular anxiety. Objectively, from looking back on your judgement/personal rule breaking you know you were narced, but because of the pre-event psychological conditions, you didn't feel it.

Thank you again for your sharing. It is particularly helpful for a diver like myself (100s of dives, but infrequent deep dives) to have these reminders.

 

[Dirty-Dog]

Thanks for the story. I've yet to experience the sort of drunk-narcosis people generally talk about. I've only done 10 deep dives, with my greatest recorded depth being 108 feet. I've specifically looked for signs of narcosis and the only thing I've ever found is that doing math in my head takes a second or two longer at depth. Seems pretty benign, but your story shows just how significant even such a small degree of impairment can become.

 

[scubafanatic]

that's why god invented 30/30

...apparently god favors rich $ divers though.....

 

[scubamountaingirl]

yes lynne, as you say, in diving to 130 often, i dont feel narc'd. I dont feel the three martini effect.

for those of us who are financially challenged, would you suggest in our attempt at cave instruction to limit ourselves until we can take a trimix class? it would make some sense if after intro to cave, trimix was offered as an addition to cave 1. But i fear that would make the cost even greater.

what are your thoughts on this?
ww

 

[TSandM]

I think Intro level dives are set up to avoid facing the diver with many situations where a little fuzziness could be lethal. Short dives on the main line aren't too bad, except for the CO2 headaches. It's when you get into complex navigation that missing stuff and making mistakes can very quickly put you in an ugly situation.

And the degree to which someone is impaired at 100 feet on Nitrox undoubtedly varies. I have problems with situational awareness ANYWAY -- it's my weakest point as a diver -- so even a little fuzziness is a really bad thing for me. Someone with a steel trap mind getting just a little slow or less alert might not cause nearly as much trouble.

 

[scubamountaingirl]

well food for thought. i have no idea if i am narc'd. i dont feel it, although i have yet to be task loaded at that depth. so i will be extra cautious. thanks for your story.
ww