Nitrogen Narcosis - Deep air dives

[johndiver999]

What exactly is your goal? To suffer from narcosis to such a degree that you feel impaired and experience a measurable
Decreases in performance? Is it to simply extend your comfort zone/depth? Something else?

I would not criticize any of those goals. But narcosis primarily effects your ability to solve novel problems. In addition, perceptual awareness decreases. If you are an accomplished diver and you are diving in a relatively uncomplex environment and you are just engaging in basic skills that are instinctive for you based on extensive experience in that environment, then your impairment is going to be hard to detect and with so little to see and do, perceptual narrowing will be harder to discern.

If your goal is to experience narcosis, then the previous suggest of sprinting for a minute or so and then see how you feel. You might also engage in a more challenging activity that might be less routine for yourself, as in remove and replace your scuba unit. Or even switch fins and masks with your buddy.

You should also realize that one of the symptoms of narcosis is to be unable to detect the narcosis. You are somewhat impaired at 130 feet. Some people a lot, others just a little.

Plus your slow and steady and frequent extension of your depth limits is something that I think helps to habituate the diver and makes him more able to cope with the impairment.

Don’t dive for 3 months and bounce down to that depth and I bet you will feel different.

 

[shoredivr]

So I am simply trying to determine for myself how impaired I actually am. Instead of opinions of others as to how narced I should be. So far I am seeing no major symptoms of narcosis. Couple of things. We are using a shotline, easy up and down. Staying only 1-2 minutes at depth, well short of NDL's, and dong NO WORK whatsoever. Its quarry diving so no currents. Its a very controlled setting. We continue to add small task loading a bit at a time. Zero concerns thus far. Would I do this dive in the ocean where there are currents and other variables... Nope... this was the dive from 2 weekends ago ... Hope you like AC/DC

I see why helmet mounted lights are a pita.

What is the maximum depth of the quarry where you are diving?

Found their FB page: 220 ft. Also they seem to be closed due to working out some details with the local county.

 

[Landlocked123]

Yup they are working out some things with the county and hopefully will be re opening soon.. Max bottom 220-230...

 

[DryCaver]

Deepest we have gotten to is 145 at the local quarry which we are still trying to map out... 8 dives below the 130 mark.. each at incremental depth .. 1-2 feet incremntal only on each... I have been doing math exercises which my buddy puts on my slate both pre dive and at depth... tracking the findings... my goal is to get to 30 dives and do a full report on it... I am seeing what I deem to be very minor impairment. On one dive I got one answer wrong out of 6.. i was subtracting negatives... .. I just am not seeing this impairment that everyone is talking about yet I know its there maybe just around the corner. We set 150 as the max bottom for air and we will bottom out the quarry at 220 in about 2 years following further training and certification to Trimix

Coming from a background where I like to think about examining problem solving (neuropsychological testing, typically looking for dementia or other cognitive difficulties) I’m finding it interesting contemplating how to test for impairment in this situation.

I’m seeing two main factors to consider- whether you are testing the correct things, and whether the test you come up with is robust to repeated testing.

On the first factor, I’d be worried about doing math as a way to demonstrate cognitive capacity. Math is an overlearned skill- many people do it a lot, and things you have done a lot tend to stay ok when you start losing capacity. I’d tend to think it would be a later loss, not an earlier one, in an impaired situation. That is to say- messing up math, if you usually don’t, would probably not be sensitive (you could have problems without messing up the math) but might be specific (as you’d have to be pretty far gone to mess up math, and if you did it seems likely to predict you are in a pretty bad place).

That said, it doesn’t seem to measure what you care about in this situation, which is your likelihood of making a life threatening decision. I suspect it of being a rather different class of capacity all together from good diving decision making.

Coming up with a better test does seem to involve looking a decision making, and evaluation of risk factors. I’d tentatively think something looking at your ability to switch set, or change your thinking paradigm, would be more useful.

There are specific tests for that, but that’s where the second factor comes into play. The whole thing about testing people figuring out novel ideas is that once they figure it out it’s no longer a novel idea. You can only use that form of test once, because then the person knows the trick, and that makes it a test of memory, rather than a test of problem solving.

So I wish I had a better solution to offer, but really, mostly what I have is a caution that doing math accurately is such a different task than staying oriented that I’m not sure data from one task can shed any useful light upon likely outcomes for the other task.

AM