Trying to figure something out

[Greendiver]

The point that I as a new diver can take away from the tests (parlor trick or not) done at the surface v. depth is this...

I will NOT be able to think or perform as fluidly at depth as I can at the surface(whether I am narc'd or just task loaded, nerves, etc). Knowing that and having it demonstrated for me proves without a doubt that I need to have a plan beforehand. With no exceptions, be prepared.

 

[TSandM]

I think one of the most frightening things about narcosis is that one often isn't aware that one is impaired at the time, but only in retrospect.

It is not the gross narcosis that you feel that is going to get you into trouble; it's the subtle impairment that causes you to make judgment errors, or get tunnel vision and lose your buddy, or misread (or forget to read) your gauges.

Here's a story that made a big impact on me: My Fundies instructor is an extremely experienced diver, who has done deep exploration and survey dives and owns and uses an RB80 rebreather. (Offered as some evidence that he's quite capable, as one has to pass a fairly rigorous evaluation to be permitted to buy one of these, and then a difficult class to be allowed to dive it.) Anyway, he was diving in a remote area with his girlfriend, where helium was unavailable. The dive the GF wanted to do was on a wreck at about 100 fsw. My instructor didn't particularly want to do this on air, but reluctantly agreed. They went down to the wreck and he had a leak from his left post. He reached up and shut the post down, but the leak continued, so he isolated and thumbed the dive (five minutes into it). On the way up, the leak persisted (as it would), so at their first stop, at 50 feet, he fiddled with the valve again, and discovered he hadn't closed it.

Now, this is a man who TEACHES this stuff, who can probably run through a faultless valve drill in his SLEEP, and he had turned the valve the wrong way. THAT's the kind of thing narcosis is going to do to you, especially when you are unaware of it. It will impede a swift and effective response to an unexpected problem.

As someone who has had a couple of EXTREMELY unpleasant experiences with paranoid narcosis, I have enormous respect for the capacity of nitrogen to interfere with my ability to make good decisions and get things done.

 

[gcbryan]

I think one of the most frightening things about narcosis is that one often isn't aware that one is impaired at the time, but only in retrospect.

It is not the gross narcosis that you feel that is going to get you into trouble; it's the subtle impairment that causes you to make judgment errors, or get tunnel vision and lose your buddy, or misread (or forget to read) your gauges.

Here's a story that made a big impact on me: My Fundies instructor is an extremely experienced diver, who has done deep exploration and survey dives and owns and uses an RB80 rebreather. (Offered as some evidence that he's quite capable, as one has to pass a fairly rigorous evaluation to be permitted to buy one of these, and then a difficult class to be allowed to dive it.) Anyway, he was diving in a remote area with his girlfriend, where helium was unavailable. The dive the GF wanted to do was on a wreck at about 100 fsw. My instructor didn't particularly want to do this on air, but reluctantly agreed. They went down to the wreck and he had a leak from his left post. He reached up and shut the post down, but the leak continued, so he isolated and thumbed the dive (five minutes into it). On the way up, the leak persisted (as it would), so at their first stop, at 50 feet, he fiddled with the valve again, and discovered he hadn't closed it.

Now, this is a man who TEACHES this stuff, who can probably run through a faultless valve drill in his SLEEP, and he had turned the valve the wrong way. THAT's the kind of thing narcosis is going to do to you, especially when you are unaware of it. It will impede a swift and effective response to an unexpected problem.

As someone who has had a couple of EXTREMELY unpleasant experiences with paranoid narcosis, I have enormous respect for the capacity of nitrogen to interfere with my ability to make good decisions and get things done.

Or it is possible that he just made a mistake. If he did a bubble check near the surface wouldn't he have found the leak earlier? If he could make a mistake near the surface couldn't he make one at 100 fsw?

This seems a little shallow (100 fsw) to automatically assume any mistake is due to narcosis.

 

[CamG]

Welcome to SB Jmarsland! Great thread for early posts. There have been some great information shared about narcosis. It is very clear that no one is exempt from its effects. Thus the importance of learning to deal with it "narcosis" in an appropriate manor. This is where dive planning and knowing ones limits becomes very important also.
Training, planning, preparation, experience can help manage the risk of narcosis but not eliminate it. As one mentioned we dive deep, we are narced to some point. From day to day the same diver can experience varying levels of narcosis even when the same dive procedures are followed. This is why diving within your limits and good buddies are priceless!
On a dive this past summer I was diving 21% at 130' did a air share drill with my buddy and he was diving 28%. Not a big difference for the first few breaths but shortly I noticed a wider field of vision, and felt more at ease. Was I narced? With out a doubt I am sure, however the difference was notable when I switched gas. This was my experience done under the supervision of an instructor in as safe an environment as possible. I am not encouraging anyone to try this if not trained and properly certified to do so. My point in bringing this up is narcosis is a constant whether we feel it or not. There are tools that with training one can learn to manage its effects safely as possible. We all as divers assume a level of risk! If we do not respect them it can be fatal. Narcosis is one such risk. Dive with in your limits, train in a safe environment, know your buddy's well, if something feels wrong ABORT!!!
Deep diving takes advanced dive planning, take the time to do it! It can and will make the dive that much better! Safe diving to you, dive with in your limits!
CamG Keep diving....keep training....keep learning!

 

[Rhone Man]

On a dive this past summer I was diving 21% at 130' did a air share drill with my buddy and he was diving 28%. Not a big difference for the first few breaths but shortly I noticed a wider field of vision, and felt more at ease. Was I narced? With out a doubt I am sure, however the difference was notable when I switched gas.

I thought conventional wisdom was that oxygen had the same or possibly greater inert gas narcotic effect as nitrogen, so that nitrox is supposed to have no benefit (or possibly make things worse) in relation to narcosis?

 

[DiveMaven]

I don't start noticing that I'm feeling narc'ed until I'm at about 120'...then I get very myopic and tend to be very focused on one thing (though I'm likely getting narc'ed from 100' or so and deeper). Because I know how I respond to being narc'ed, when it happens I work very hard to not be so tunnel visioned, but typically head to a shallower depth about that time. Since my husband is a photographer, we tend to stay shallower anyway, so it isn't often I get down to the 120'+ level.

On the other hand, my husband begins to feel "drunk" at about 100', so he prefers to stay shallower than that when possible. I've never felt drunk and he's never felt tunnel vision when narc'ed, so it is totally individual how you'll respond.

 

[String]

I thought conventional wisdom was that oxygen had the same or possibly greater inert gas narcotic effect as nitrogen, so that nitrox is supposed to have no benefit (or possibly make things worse) in relation to narcosis?

Meyer-Overton and other theories put Oxygen as or more narcotic as nitrogen and as a result most people agree it is narcotic.

"Less narcosis" is simply not true with nitrox. Placebo, like in many other areas, can have a big effect on results though.

 

[kathydee]

I don't start noticing that I'm feeling narc'ed until I'm at about 120'.

I feel start feeling narked at 28.5 meters or 93 ft - all the sudden: everything seems to move a bit slower, the water pressure suddenly seems to be much greater, I am really happy & amazed by everything (if it's not a dark narc).

In a very subtle way, concerns for things such as pressure and depth gauges, becomes secondary to the surrealistic beauty -- it's almost as though I am being drawn into the allure of the incredibly mesmerizing deep, unless I pay close attention to my gauges.

I usually start paying close attention around 27 meters or 88ft just before the narc starts and stick to predive depth limits, closer to my partner and check gauges more frequently when below 25 meters or 80ft or when the feeling comes on. It's good to know your own limits!

 

[acooper]

Just did our deep dive for AOW cert. I was really wanting to see where my limit is, but was disappointed when I felt nothing when we hit the sand at 116ft. Our instructor had a math problem to do, long multiplication, no problem. While I waited for the others to do their drills I photographed a nudi on a rock and had no issues flipping modes on the camera. After the training and reading up on narcosis (including the decent Wikipedia article) before the dive to review the symptoms I felt no different than a 20 or 40ft dive.

I wonder if the fact that I operate in a stressful hypobaric situation at 13,600ft elevation for a full shift a couple times a week, doing technical work, has trained my mind to compensate for impairment?

I don't know if I will press it any deeper any time soon, a lot of stuff and a lot longer dives when operating shallower.

 

[kathydee]

I wonder if the fact that I operate in a stressful hypobaric situation at 13,600ft elevation for a full shift a couple times a week, doing technical work, has trained my mind to compensate for impairment?

I wonder what affects narc limits. I do have a small body frame and mass. Litterally feel a bit buzzed with 1/2 a beer (which can be great!) and am strongly affected by almost any drug with side effects.

But I have done extensive meditation in the past so also am very in tune with any change in my mind or body.

Does anyone know the physical factors that affect narcosis ?