I want to get narked

[DiveLikeAMuppet]

I think it's a matter of mental capacity. Narcosis limits the capacity that is available to you, so in clear water, at a known dive site, you still might cope with basic diving at significant depths. In poor visibility, on a more demanding dive, if something unexpected happens...

I feel narcosis as if someone put a blanket over me, everything calms down - around 30 - 40m on air, in in 2-3 meters visibility. I miss that feeling on trimix completely.

At 40-45m, I start to get mentally impaired. As good practice, on OC I calculate my remaining gas every 5 minutes based on average depth and known SAC, and then compare to what I see on my SPG. When I'm more narked, I can still do the math but it's slower or I might "forget" some of the numbers or have to check the SPG multiple times, unless I fully concentrate and break it down into individual steps.

Short-term memory is also pretty affected. I have to make a drawing of what I saw underwater as soon after surfacing as possible, as I might forget it otherwise (record some GoPro footage at depth, you will be very surprised by all the details that you missed or can't remember...)

Few really dark narcs' made stop diving air when I simply couldn't check my gas (calculating 220 - 4x15 was impossible) and I started to feel like I would rather not be down there. Most likely a factor of hard work due to current (= CO2) and task loading - new dive site, bigger dives, fishing nets on the wreck, poor visibility so the limited mental capacity is simply used up on something else.

 

[Superlyte27]

A quick google indicates that most decompression chambers do not go "deep" enough to produce narcosis. The Navy tanles only call for recompressing divers to an equivelant of 60 feet, and medical HBOT chambers don't even go that far.

Be interesting to build a chamber that went to 6 ata (90 psi, 200' equivelant) that could simulate a bounce dive for exactly this purpose. Bonus if you could have a mask inside with trimix so the "diver" could immiedatly see the difference.

This is not accurate at all. I was a chamber operator for 20 years. Do some better research.

 

[OTF]

The problem with doing these tests in a dry chamber is that, for reasons generally unknown, the human body seems to be SIGNIFICANTLY more resistant to narcosis and oxtox in dry chamber dives vs open water dives.

 

[Superlyte27]

The problem with doing these tests in a dry chamber is that, for reasons generally unknown, the human body seems to be SIGNIFICANTLY more resistant to narcosis and oxtox in dry chamber dives vs open water dives.

The reasons aren’t unknown. I can list some of them here….

Cold, darkness, fear, all contribute to narcosis.
Stress, workload, comfort all contribute to narcosis
Work of breathing and co2 buildup all contribute to narcosis.

Now, get in a chamber and all of those things (except cold) are almost completely eliminated in a chamber.

With that said, it’s super easy to measure narcosis in a chamber once you go deep enough.

Math, reciting the ABC’s, signing your name, singing “Mary Had A Little Lamb”, I’ve used all of these and more to determine narcosis. I’ve even told lame jokes to see how ridiculous a reaction. A diver had gotten the giggles for over 20 minutes due to a stupid joke. Want to hear a joke about cats? Never mind, just kitten.

 

[rjack321]

A quick google indicates that most decompression chambers do not go "deep" enough to produce narcosis. The Navy tanles only call for recompressing divers to an equivelant of 60 feet, and medical HBOT chambers don't even go that far.

Be interesting to build a chamber that went to 6 ata (90 psi, 200' equivelant) that could simulate a bounce dive for exactly this purpose. Bonus if you could have a mask inside with trimix so the "diver" could immiedatly see the difference.

This is why google is not knowledge. There are Navy tables that go deeper than 3ata - on air. And yes you can show impairment in chambers even at 3ata although it won't correlate to diving anyway

 

[OTF]

The reasons aren’t unknown. I can list some of them here….

Cold, darkness, fear, all contribute to narcosis.
Stress, workload, comfort all contribute to narcosis
Work of breathing and co2 buildup all contribute to narcosis.

Now, get in a chamber and all of those things (except cold) are almost completely eliminated in a chamber.

With that said, it’s super easy to measure narcosis in a chamber once you go deep enough.

Math, reciting the ABC’s, signing your name, singing “Mary Had A Little Lamb”, I’ve used all of these and more to determine narcosis. I’ve even told lame jokes to see how ridiculous a reaction. A diver had gotten the giggles for over 20 minutes due to a stupid joke. Want to hear a joke about cats? Never mind, just kitten.

Agree that the many contributing factors are well understood. But have we worked out the underlying biological mechanisms for why they affect narcosis intensity and onset? (And perhaps tangential, but more notable and strange, oxygen toxicity?)

It would be interesting (or at least entertaining) to do controlled experiments on land using nitrous to test inebriation and performance while comfortable vs. cold wet and stressed.

CO2 is a huge factor, I think you're the first person to mention it in this thread. I suspect that the more noticeable narcs I've experienced were partially CO2. It's important to consider in a world where most deeper diving is done with helium and CCRs and narcosis is less of an expectation than days past. Carbon Dioxide, Narcosis, and Diving

 

[BRT]

Agree that the many contributing factors are well understood. But have we worked out the underlying biological mechanisms for why they affect narcosis intensity and onset? (And perhaps tangential, but more notable and strange, oxygen toxicity?)

It would be interesting (or at least entertaining) to do controlled experiments on land using nitrous to test inebriation and performance while comfortable vs. cold wet and stressed.

CO2 is a huge factor, I think you're the first person to mention it in this thread. I suspect that the more noticeable narcs I've experienced were partially CO2. It's important to consider in a world where most deeper diving is done with helium and CCRs and narcosis is less of an expectation than days past. Carbon Dioxide, Narcosis, and Diving

No question that CO2 narc is worse.

 

[grantmac]

I have a friend who gets so narked past 25m that they really can't be responsible for their own safety. They have a cleft palate which was surgically fixed but still has a lot of gas interchange between the mouth and nose to the point where they aspirate water during any mask clearing.
The more I read the more I think they are likely an excellent candidate for a FFM and that their nark might be a result of poor co2 clearing.

 

[Cthippo]

This is not accurate at all. I was a chamber operator for 20 years. Do some better research.

So how deep can you go with the chamber you operated? I'm genuinely curious.

 

[Lorenzoid]

CO2 is a huge factor, I think you're the first person to mention it in this thread...

C'mon, CO2 was mentioned in post #2 in this thread.