How Does Narcosis Effect You?

[The Chairman]

You guys are telling us how deep you've gone, not how narcosis affects you. That's kind of interesting.

 

[Subcooled]

Long ago we were diving at 155 feet on air (availability and cost issues with He) while following a guide line. My SPG got stuck between a log (tie off) and the line. I moved my hand back and freed myself. Then resumed swimming to only notice that I was still stuck. I had made a swinging arm movement without remedying the problem. I believed I solved the problem. It took a second attempt and some focusing to place the hand on the SPG and to command the fingers to actually act.

On another dive I noticed how my two eyes were momentarily out of sync. When the ceiling appeared in sight, it appeared at two levels. I saw two pictures (left and right) that moved and swayed a bit untill they joined into one. ppO2 was one. I guess this problem was due to slowing of brain function.

 

[Subcooled]

See the attached picture.

This test was done in a dry chamber at 6 ATA. Pay attention to task #2 (join the points in order A-1-B-2 with a line). And so I did. A-1-B-2. I do remember how I thought hard whether I should connect A and 1 and B and 2 or ALL the points. My logical conclusion was to connect those four points explicitly named in the task.

In task #4 I tried to calculate (35+6+2-1)/2. I had to actively STORE into my mind (and that was hard work) a number, a second number, and an operation, and then perform that operation. Finally, I had to STORE the result and repeat. Each step took several attempts. So... 35, 6, plus, ...., 41, ..., 41, 2, plus, ...., 43, ... 43, 1, plus, ..., the result is 44 (several moments of confusion and failure and new attempts have been removed). Apparently, despite all effort, I failed to properly overwrite plus with minus in my mind. I had stored plus twice so storing minus once was not enought to overwrite... I did verify my calculation and I did notice this error. The result was, then, 42. I had still failed to recognize division by two. Dealing with three mathematical operations far exceeded my capabilities at 6 ATM air. At this point I had been studying mathematics for four years in university. You may be more gifted.

A biologist was also in the chamber. She thought that cows drink milk.

 

[Kevrumbo]

Resurrecting my own Deep Air/Dark Narc encounter to 80m on Oil Rig Eureka here in offshore SoCal 2yrs ago, in 12deg C water temp depth at the time. Used double AL80 11L manifolded cylinders, an AL80 11L tank of Oxygen, a drysuit for exposure & redundant buoyancy, and a DPV Scooter.

Planned dive was a quick powered scooter descent to 90m for a few minutes, and then multi-level profile up with most of the time spent at 18m, with O2 deco at 6m as needed. Total Dive Time was 50min, with deco obligation cleared before 12m (per Petrel Computer on 30/85 GF), but I did a few minutes on O2 at 6m anyway for a cleaner inert N2 purge.

With the scooter off and stowed, all it took was three forceful & physically exerting frog kicks into the stiff current at 80m depth, and I was instantly overcome with a narcotic CO2 hit: Hyperventilation & difficulty breathing the regulator, high density & flow viscosity of the Air mix & resulting Hypercapnia came on immediately. In the dim ambient light, the only thing I was able to perceive was my Dive Computer flashing an extreme PPO2 Warning prompt of 1.9, and it took a few minutes focused concentration not to panic, just to hang onto a support beam and try to relax & regain a nominal breathing rate & clear head before starting the ascent using the scooter. (Note: Elevated CO2 also increases the likelihood of hyperoxic seizures.) The point is that a Deep Air bounce dive like above can be treacherous enough even if planned and prepared as a technical dive on double tanks with plenty of gas supply margin to recover at depth from Hypercapnia . . .It would be dangerous and near fatal tragedy to make this mistake on a Single Tank!

Not at all pleasant and I don't want to do that again. . .

 

[Tug]

Below 130' in cold water I start to get a lot more paranoid so I'll usually throw some helium in my backgas below 110' or 120' depending on the dive. Now that I'm diving a rebreather primarily, I'll more often than not have some helium in my diluent.

 

[Scott]

Mine was 10 feet deeper than any card I carry says I can.
The more intense the narc, I start to get tunnel vision and loose some coordination.
Sometimes I experience a buzzing sensation between my eyes.
On those types of dives I go very conservative on gas planning and limit the tasks that I perform.

 

[TMHeimer]

Deepest was 131'. A few times to 110, 120, etc. Didn't notice any effect though I assume my reactions were slower as this is generally accepted. Perhaps being very focused on my gas and my collecting, I just didn't notice.

 

[Jared0425]

It depends, one days you feel fine the next things go bad. It all depends on sleep, mood, and diet. I was comfortable on doing air dives between 100-190+ when I was with other helium divers. My skill and reaction tine seemed alright in those ranges. If the vis was great and I knew the layout of the wreck, I discovered that I was quite comfortable with a drunk buzzed feeling without the blurred vision or bad decisions (except diving on air). I felt that I could handle whatever happened and followed tables with little to no deviation. On other days, I wish I could have backed out without hurting my ego. Below 100 in darker water, it turned to dark narc. I got tunnel vision, my paranoia was through the roof, ringing in my ears, my breathing labored, and funny sounding bubbles and sounds. I had difficulty understanding my computer and tables along with the absolute rule of thirds.

Then about a year ago I did a relatively shallow dive to 150' on air when my reg free flowed. I knew what was coming a few minutes before it happened as I was already uncomfortable and heading back towards the line. I knew I had more than enough air to swim to the line without shutting down the post in the meantime. When I got to the line I started my ascent and shutting down the reg. It was too deep to switch to any deco at the time so I spit the bad reg out of my mouth and thought I had put in my second... I was wrong, the bad reg was hung in the area of second good reg so I thought I had the good reg when I in fact did not. I started to drown and before I blacked out I managed to get the good reg in. At this time I was in a unknown rapid ascent and blew through 3 stops with a screaming computer. First thing I did was stop the ascent and hold on to the line until I had regained my control of buoyancy, then had to mentally refigure deco. My nerves were shot to hell so my thinking was off. I extended my stops and got to the last when my legs went numb along with the rest of my body. Fearing the worst that I took a hit, I got to the surface and got out of my gear and went back to my 100% deco, then in 10 seconds it was gone. My own nerves faked a hit. My analysis kinda told me if it was not for unfelt narc,

1. I would have immediately realized that my reg was going to go when it was making the unnoticed noise a few moments before I recognized what was happening and would have ended the dive sooner.

2. I would/should have immediately shut down the post instead of letting it go for a few minutes no matter air quantity or capacity in my doubles.

3. Kept my secondary reg around my neck instead of clipped to my chest, along with taking the bad reg out by hand and tucking it instead of spitting it out where it hung up on my secondary clipped to my chest. Still not a fan of long hoses and will probably shorten that thing up to normal.

4. I would have never let my ascent go unchecked like it did. I have hundreds of dives and many deep. My skills are on great along with my drills as I practice with the best of divers, but that was one rookie mistake that could have seriously have done me in and there was no excuse for it with my experience. Meaning narcosis affected me far more than I would have believed.

Now every deep air dive (what's going to be the last of them), my perception to narcosis is much more noticeable and now it seems to be nothing but dark narc when doing tech depths, no matter the conditions which is why I'm going to give HE a chance to regain my composure. Lesson is, air will do as long as things go right. It's when sh!t goes wrong is where the problems with deep air diving occur whether you believe you are not narcd or are. Take this as a lesson if you are going to do it.

 

[FLDiver1991]

It amplifies whatever mood I'm in. If I'm enjoying the dive, I enjoy it more. If I'm anxious about something, not often am I anxious while diving, I become more anxious.

That, and I forget the term, but it's like "tunnel vision" for a specific task. I once had to dive w/ a different gear load-out than usual due to extenuating circumstances and I was so set on not plummeting to my death( was a deep dive, wasn't sure what the bottom was before I jumped) that I failed to notice my ppo2 warning blinking above my limit even though I must have checked my dive computer 4 or 5 times on the descent.

 

[KevinNM]

On the deep dives in the PADI deep course I had no issue with tasks that required mechanical skill, but I was toast on mentally challenging things. When I got back up I realized I had no idea of my NDL or pressure once I reached 129. Never even noticed it despite it being on my wrist. The download says I hit the NDL and then we ascended, but that was the instructors call.

Doesn't encourage me to do deep dives on air.