Narc'd? First Deep Dive...

[evil_xander]

Just last week I had my first obvious narced dive ever, previous dives I cannot comment as I don't really think anything happened, but who knows...

The effect? I was laughing wholeheartedly at 36 m and was completly aware what's going on and what should I do to make it stop, but was enjoying it soo much, I just had to spend a couple of minutes laughing.

It made my day.

p.s. 75% of all my logged dives are in range from 30-43 m, just checked, this never occured before, all dives made on air.

 

[Matt S.]

But there is a real form of tolerance that people get to drugs and alchahol over time, which is basically the destruction of the receptors for that particular compound in the brain. I'm curious to know how the Nitrogen and or Oxygen react with the brain under pressure to cause narcosis, if they react similar to many narcotics, than people can in fact build up a real tolerance through repeated exposure, although in reality that would jsut be the narcosis destroying receptors on the brain. ?

Anyone know the answer to that , because I am quite curious.

If you do find material on that, please post a followup. I did biochem in school, and while I don't do it professionally I remain a science geek.

 

[MatthewK]

I'm a newbie and haven't been deeper than 60ft.

But I'm also a dentist, and we "narc" people routinely with different drugs. Speaking of inhalation narcosis, specifically N20, "laughing gas," there are numerous factors that can contribute to the depth (meaning level or intensity, not fsw) of anxiety reduction or "sedation" achieved from N2O.

Yes, individuals can reach a different levels of "anxiety reduction" or "light sedation" with the same rate of administration of N2O, but on different visits.
The same principles should apply with fsw depth, as many factors including ones own level of anxiety at that time, come into play.

As to what is going on at the biochemical level in the brain with N2O: the honest answer is we don't know. Many studies have been done but to date, as far as I'm informed, we don't have an answer.

And to add one last note, N2O abuse leads to neuropathy with many abuser losing sensation in their fingers and other problems. I don't know whether studies have been done to determine if neuropathy is also evident with deep divers that self expose to nitrogen narcosis on a repeated basis.

 

[lamont]

I'm sorry, but, respectfully, that statement is misinformation IMO. Not EVERYONE gets "narc'd" at that kind of depth. Could they? Sure, but NOT always. On top of that, "helium" (I'm assuming you mean trimix) get's REAL expensive when used on that "shallow" of a dive, EAN is a much better choice. Sure, 130 and below, consider trimix.

But, all this discussion aside, getting "narc'd" is really more an individual's EXPECTATION than EXPERIENCE. What I mean is, if you THINK you will get "narc'd," you WILL get "narc'd." You need to have a mental "toughness" to prevent this. When I used to dive deep air (130 to 170), we'd always "work down" to that depth. We'd start in a 140 FT quarry with progressively deeper and longer dives (it was darn cold too). Two weekends of this followed by a few 150+ FT offshore, then deeper. I always found that when I was well rested, prepared and had the "right" mental attitude about deep diving, I never had a problem. In other words, I functioned correctly, remembered turn pressures, tracked air and BTs without problems and had a clear memory of everything we did on the dive.

Did I practice math problems to "prove" it? Nope, I was too busy looking at the wreck...

You are training yourself to drive drunk, but you are still driving drunk.

Everyone is narc'd to some degree below 80 fsw. The level of impairment is highly situationally dependent, and you can learn strategies to work around the impairment, but you're still impaired. The only way to remove the impairment is helium.

 

[TSandM]

I'm curious, as a doctor how do you explain that? I would think that the narcotic effect would be the same every time and that any other impairment that could vary would be from anxiety but how would anxiety actually cause hallucinations?

My guess is that CO2 may have played a role, as I was anxious about the poor viz. In addition, the limited vision makes me much more acutely aware of kinesthetic input, and the "hallucinations" I had were that I was initiating an uncontrolled ascent that wasn't actually happening. I dumped all the gas out of suit and wing, and wallowed in the silt until my brain caught up with the reality that I was NOT headed for the surface. It was not fun.

Another time, I became convinced that my regulator was not functioning properly and was failing to deliver enough gas. I talked myself through that one, and it wasn't true, either.

Although I'm too lazy to look up the citations in the Rubicon database, there are some very interesting studies showing no significant adaptation to narcosis, although the subjects reported a subjective feeling of better performance.

 

[Drewski]

You are training yourself to drive drunk, but you are still driving drunk.

Everyone is narc'd to some degree below 80 fsw. The level of impairment is highly situationally dependent, and you can learn strategies to work around the impairment, but you're still impaired. The only way to remove the impairment is helium.

There is NO comparison between ETOH and Nitrogen Narcosis, no matter how much people try and simplify the relationship.

Please explain to me the "mechanism" behind how Nitrogen Narcosis affects the brain and results in changes to perception, abilities and mentation. When you can do this, scientifically, then we'll have a conversation about "comparing" it to ETOH.

Is there a depth where the discussion is academic? Obviously. But "impairment" is a relative term. There are already posters on SB who say:

If you are planning a dive to 130 ft then your best mix would be TMX 25/35. You really should not be diving air deeper than 50 ft. And I would not dive nitrox deeper than 100 ft.

I'll go back to what I said before and I'll say it again. People who rely more on equipment, "gas" and other "technical means" to replace experience are only fooling themselves.

Fewer posts... More dives.

 

[lamont]

There is NO comparison between ETOH and Nitrogen Narcosis, no matter how much people try and simplify the relationship.

Please explain to me the "mechanism" behind how Nitrogen Narcosis affects the brain and results in changes to perception, abilities and mentation. When you can do this, scientifically, then we'll have a conversation about "comparing" it to ETOH.

I'd recommend whatever the 8th ed of The Biochemical Basis of Neuropharmacology by Cooper, Bloom and Roth has as a starting point. I think I only own the 6th and 7th editions, though, so I might be a few years out of date. It does appear though that at least some of the anesthetics like halothane and isoflurane affect GABA-A receptors which place them neuropharmacologically more similar to benzodiazepines and EtOH than your state of denial will accept.

Anyway, I'm claiming an analogy between diving under narocosis and driving under the influence as comparable human psychological issues involving equal amounts of denial and rationalization. The mechanism of action is largely irrelevant. The same psychological mechanisms underly people who drive drunk, drive stoned or drive sleepy.

Is there a depth where the discussion is academic? Obviously. But "impairment" is a relative term. There are already posters on SB who say:

I'll go back to what I said before and I'll say it again. People who rely more on equipment, "gas" and other "technical means" to replace experience are only fooling themselves.

I never claimed that helium could replace experience. I agree with everything you said about diving the Doria and the complexity of the dive with the depth, the currents, the task loading, etc. I even agree about people who do replace experience with helium, and I do see this around me right now and choose not to participate in it. I still think your attitude towards progressively building up a 'tolerance' to narcosis is a practice with a bodycount that nobody but a few dinosaurs will be doing 10-20 years from now.

 

[lamont]

There is NO comparison between ETOH and Nitrogen Narcosis, no matter how much people try and simplify the relationship.

Please explain to me the "mechanism" behind how Nitrogen Narcosis affects the brain and results in changes to perception, abilities and mentation. When you can do this, scientifically, then we'll have a conversation about "comparing" it to ETOH.

The more I think about it the more this is completely laughable, and a good example of why no matter how much diving Drewski has done his logic is flawed and not credible.

EtOH and Benzos affect primarily GABAergic receptors, Ketamine and PCP are NMDA receptor antagonists, LSD and DMT are 5-HT2A receptors antgonists , cannabis affects anandamide receptors, opiates affect opiate receptors, MDMA is a 5-HTergic reuptake blocker and releasing agent, etc.

They've all got widely differentiating mechanisms of action, and from where I'm sitting its up to you to prove that N2 is so substantially different from them, and that diving is such a different kind of activity that the analogy between driving under the influence of any of these chemicals cannot be applied to diving under N2.

Fewer posts... More dives.

Read a book. Cooper, Bloom and Roth would be a good start.

 

[gcbryan]

My guess is that CO2 may have played a role, as I was anxious about the poor viz. In addition, the limited vision makes me much more acutely aware of kinesthetic input, and the "hallucinations" I had were that I was initiating an uncontrolled ascent that wasn't actually happening. I dumped all the gas out of suit and wing, and wallowed in the silt until my brain caught up with the reality that I was NOT headed for the surface. It was not fun.

Another time, I became convinced that my regulator was not functioning properly and was failing to deliver enough gas. I talked myself through that one, and it wasn't true, either.

Although I'm too lazy to look up the citations in the Rubicon database, there are some very interesting studies showing no significant adaptation to narcosis, although the subjects reported a subjective feeling of better performance.

I'm just noticing that in these discussions of nitrogen narcosis that many other facts are discussed under this heading that are actually distinct. In this case CO2 would still be present if you were shallow breathing and anxiety could still be present if viz was bad even if there was no nitrogen narcosis involved. In other words if I understand your description of this incident in your past this could have happened even on trimix or to look at it another way, it could have happened at 50 fsw.

I agree that narcosis happens when it happens and also makes everything else worse so adapting to it is probably not what happens with experience but adapting to poor viz thereby eliminating anxiety and CO2 does seem to explain why some have more problems with depth than others.

 

[TSandM]

You may be right, Gray, but I've been in very poor visibility more shallow, without ever having anything like this. It's been reproducible in essentially the same site -- Olive's Den (logs at 100 fsw), or the bottom of the I-beams (also 100 fsw). For this reason, I restrict myself to dives above that in the PNW.