How To Experience Narcosis With Minimal Risk?

[rhwestfall]

My LDS has, as part of the Master Diver curriculum (NAUI), a chamber dive. Interesting to sit with a few folks, and see how impacted or when some become impacted. Dive computers are brought into the chamber too (in a bucket of water). The only "drawback" is that it is part of a dive trip, so you lose a dive (or more) with nitrogen loading as part of the chamber dive....

 

[Bob DBF]

I have been thinking the same lately. I will be taking a class soon where I have to dive to 130 ft in cold dark water with an instructor and have been contemplating using air to increase the chance of a narc to see what it feels like. My thought is to try it once to understand the effect and then avoid it in the future.

Going to 130' in cold dark water to experience narcosis, with anyone, is not the best plan for your first encounter. I would suggest dabbling in it at a shallowerdepth as you have no idea how it will affect you, I've seen divers become useless at 100'.

The greatest problem with narcosis is that, unless you are actively looking for it, you will not feel impaired until something goes wrong, at which time you will find out how impaired you are the hard way. I do not advise this method, even though I'm kind of a traditionalist.

Not to say I am great at dealing with narcosis, but I have learned enough to stay alive so far. One thing I do when I have not been doing deep dives regularly, even though I think I know how narcosis affects me, is to make a number of "training" dives, progressively deeper, to evaluate my ability to handle task loading without losing the basics of gas, time, and depth and ascend when my plan calls for it or has been broken. When in doubt, I head up. You should not rely on another to "save" you as narcosis can be whimsical, and your buddy may need your help.

When I started diving deep, air was the only choice. By the time helium was being used I had stopped doing the dives I feel I should have had it for.


Bob

 

[lowviz]

Going to 130' in cold dark water to experience narcosis, with anyone, is not the best plan for your first encounter. I would suggest dabbling in it at a shallower depth as you have no idea how it will affect you, I've seen divers become useless at 100'.

I'll begin to feel compromised between 60 and 80 feet under adverse conditions. See my post above. Someone mentioned to me on that dive that I had a mask 1/4 full of water. I said "I know, I was getting around to that..." It is always the same, just stalled there not doing anything or even thinking. The best example that I can give (from personal experience) is being narced is very much like getting up too early in the morning and you find yourself staring into the mirror with a safety razor in your hand. You know what to do, how to do it, but nothing seems to be happening for a moment or two. Being narced is neither a pleasant nor an unpleasant feeling. You are just compromised and it rapidly gets worse with depth. Nothing all that inherently interesting about it, just something to avoid.

OP: If you are still interested, best if you work at finding the shallowest depth that affects you. Don't go bombing to the bottom on air just to see how it feels.

The greatest problem with narcosis is that, unless you are actively looking for it, you will not feel impaired until something goes wrong, at which time you will find out how impaired you are the hard way.

This is good advice.

 

[KDAD]

Good idea. I can do some dives to work up to 130 fsw. There are a few dives that I can do starting at 65 and some at 95 to 100 feet, both in cold, dark water, with same instructor, before going to 130 fsw.

Going to 130' in cold dark water to experience narcosis, with anyone, is not the best plan for your first encounter. I would suggest dabbling in it at a shallowerdepth as you have no idea how it will affect you, I've seen divers become useless at 100'....

One thing I do when I have not been doing deep dives regularly, even though I think I know how narcosis affects me, is to make a number of "training" dives, progressively deeper, to evaluate my ability to handle task loading without losing the basics of gas, time, and depth and ascend when my plan calls for it or has been broken. When in doubt, I head up. You should not rely on another to "save" you as narcosis can be whimsical, and your buddy may need your help.

Bob

 

[lowviz]

One more piece of the narcosis puzzle to keep in mind. Meds.

In the shallow dive referenced above, I was on scopolamine and promethazine due to rough conditions. One scope patch and 12.5 mg promethazine. I passed on using phenylephrine to keep me awake. Figured I'd just brass through it, Sudafed raises my blood pressure. Narcosis is best evnvisioned as a nebulous fog, you can't ever pin it down or define its limits.

 

[Kevrumbo]

CO2 Narcosis (the "dark narc") is the more insidious and potentially more dangerous than Nitrogen narcosis.

There is no way to experience this with minimal risk; the only way to recover is to cease & desist all physical exertion and try to re-establish a normal & relaxed full breathing pattern again, and/or immediately abort the dive.

Deep Air with increased Gas Density & Work-of-Breathing; then throw in Physical Exertion or a Stress Condition, resulting in overbreathing the regulator, hyperventilation & inefficient breathing at depth (also can result from breathing a malfunctioning "wet regulator") --all leading to the Vicious Cycle of CO2 Retention and sudden Narcosis, with increasing susceptibility to Ox-Tox seizure. Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . .

Taken from Undersea Biomedical Research, Vol 5, No. 4 December 1978 Hesser, Fagraeus, and Adolfson:
Studies on the narcotic action of various gases have shown that the ratio of narcotic or anesthetic potency of CO2 and N20 approximates 4:1, and that of N2O and N2 30:1. From these figures it can be calculated that CO2 has at least 120 times the narcotic potency of nitrogen. Our data would suggest that the narcotic potency of CO2 is even greater, i.e., several hundred times as great as that of nitrogen." (emphasis added).

Hypercapnia - Wikipedia, the free encyclopedia

Carbon Dioxide, Narcosis, and Diving | Global Underwater Explorers

 

[lowviz]

...//... resulting in overbreathing the regulator, ...//...

No way, and you know it. A modern reg at recreational depths?

Anyway, the issue is between Tachypnea and hyperventilation. They have very different effects on the body.

 

[Kevrumbo]

No way, and you know it. A modern reg at recreational depths?

Anyway, the issue is between Tachypnea and hyperventilation. They have very different effects on the body.

Originally Posted by TSandM
Overbreathing the regulator MEANS a CO2 hit . . . It means the increased work of breathing of using a regulator is enough, at the current demand, to prevent you from exhausting all your CO2. All regulators can deliver more gas, faster than you can use up oxygen, but the small increase in resistance involved in triggering the inlet valve and opening the exhaust valve can make the difference between being able to keep your CO2 normal under heavy work loads, and not being able to keep up. Panic in the experienced diver?

Originally Posted by TSandM
CO2 in the bloodstream is completely determined by minute ventilation, assuming the gas you are breathing does not contain additional CO2. Bailing to open circuit definitely makes it POSSIBLE to reduce the blood CO2 level, assuming you can achieve a higher minute ventilation than what's required to keep the CO2 where it is (which is in part related to level of exertion). It may not, however, be possible to reduce CO2 fast enough to clear your head and get rid of the panicky feeling, in part because the natural tendency when panicky is to breathe as fast as possible. On scuba, this means reducing the efficiency of the ventilation, because too much of it is just going to exchange gas in the trachea and large bronchi, which don't exchange gas. That's why we are taught in OW that, if we begin to "overbreathe our regulator" (meaning the diver feels short of breath despite breathing as much as he can), we are to STOP, hang onto something (reduce exertion) and breathe SLOWLY and DEEPLY. It is then possible to reduce CO2. What may not be possible is to stay rational long enough to do it. Panic in the experienced diver?

 

[lowviz]

...//... if we begin to "overbreathe our regulator" (meaning the diver feels short of breath despite breathing as much as he can), ...//...

There is our issue. Semantics, not mechanics...

 

[Kevrumbo]

There is our issue. Semantics, not mechanics...

Mechanics & Patho-Physiology can be the same --whether at depth or on the surface:

It can even happen on post-dive/diveboat recovery, with hard physical exertion in large breaking swells and current, over-breathing the reg with water continuously swamping over you, trying to get back & board the diveboat: it literally felt like I was drowning on the surface. . .Diver Panic (Video)