Getting narced.

[simon66]

Originally posted by Heads Up
BUT should sometime happen that is unexpected, the narcosis may become overwhelming and make your judgement / reactions SEVERLY impaired. This is a law of physics and NOT something you can overcome through experince (IMHO)

I understand what your saying .Our dives are normal depths of 15 to 40 metres but the last few was to test our own reactions to narcosis at a deeper depth should an incident ever occur where we would have to go deeper e.g a rescue.I`d like to know my self if i was able cope under these conditions to help my buddy if anything went wrong . You have to know your max depth you`d be fairly safe to go to should you be required to .As Divesherpa said "It's unbelievable how narced I was past 200 fsw. Let's just say I won't be going below about 165 on air ever again. "


As for what i put down "as getting used to it" , what i meant was if you only ever dive to 20 metres and maybe only once a month then you do a 40 metre dive the narcosis effect may spin you out where as doing diving every weekend and doing buildup dives to 40 metre would help your head stay clearer , I find it does anyway .
:approve:
simon
Tdi Adv Nitrox & Deco proc,Bsac Dive Leader certs

 

[Heads Up]

I guess we actually agree, although we appear to be saying different things. I too dive deeper to experience the enhanced effects of narcosis so that I can become acclimatised to it - I realise that I am still suffering the exact same effects as always, its just that I am able to recognise it and 'handle' it a bit better.

Poss see you at 50m in Dorothea some time!!

 

[simon66]

Was there last sunday , viz was good loads of divers there and no accidents thank god .
Their trying to close it at present until the site is set up right , but when will this happen !!! . Don`t think anything will be done , cause this is an excellent place for tec diving and training .
Down there in March again .

Simon .

 

[Arduous]

Uncle Pug is right Voidware, your not going to get narced at 60 feet and the vertigo was probably brought on by the low visibility ( not being able to judge where you are ) and or pressures on the ear.

I dive only in the cold waters of New England and here in the spring the water temperature at depth is in the low 30’s. I often dive to 70 or 80 feet with no perceivable effects. However the fact is that when I hit the 80 feet and beyond mark I am going to be narced to some degree, whether I perceive it or not. It’s my believe that the more you dive deep ( below 80 feet ) the less susceptible to the effects of narcosis you will be. That is only to say that with deep diving experience you will be better prepared to handle an emergency situation at depth, should one occur.

Dive Safe ………………….Arduous

 

[Hobbs]

This is from a link I found wich I must state that I truly agree with it from my own experiences.

Everything will be ok as long as nothing is going wrong. !
Then it gets real ugly instead.

TABLE 1: A summary of the classic view of the progressive effects of nitrogen narcosis.

4ATA (98 fsw) Mild euphoria, delayed responses

6ATA (164 fsw) Sleepiness, hallucinations, impaired judgement; laughter and loquacity may be overcome by self control.

8ATA (230 fsw) Convivial group atmosphere, severe impairment of intellectual performance, uncontrolled laughter or terror reaction in some.

10ATA (299 fsw) Stupifecation, mental abnormalities, euphoria, almost total loss of intellectual faculties.


The link is
http://www.techdive.nu/artiklar/narcosis.htm

Personally when in a highten state of awareness I have been feeling the effects of narcosis at a depth at around 18 meters. not much but it was there.

Dive safe dive within the limits !!!

 

[Uncle Pug]

Originally posted by Hobbs
Personally when in a highten state of awareness I have been feeling the effects of narcosis at a depth at around 18 meters. not much but it was there.

Dive safe dive within the limits !!!

Good for you Hobbs....

You must be a tuned in kinda guy....

What cracks me up is the guys who brag about not feeling narcosis!!!

As though that is something to be proud of...

 

[simon66]

uncle pug ,
do you use nitrox if so you`d be aware of the advantages over air i.e as quoted from tdi advanced nitrox training manual " some divers report that they experience less nitrogen narcosis , or have a clearer head during deeper dives on nitrox ." .

I nearly always use a nitrox mix .
simon .

 

[Hobbs]

Originally posted by simon66
uncle pug ,
do you use nitrox if so you`d be aware of the advantages over air i.e as quoted from tdi advanced nitrox training manual " some divers report that they experience less nitrogen narcosis , or have a clearer head during deeper dives on nitrox ." .

I nearly always use a nitrox mix .
simon .

Since no one in their right mind would ever go deeper on nitrox than they would go on air.

I do however think I know why your statement is correct, ie why they feel less of the nitrogen narcosis.
the reason is to be found in the ammounts of gasses within air and nitrox.

In short
when filling nitrox you fill the bottle with oxygen to a certain ammount of preasure (defined by the nitrox oxygen level you want.) then you fill it up with air. That means that there are a lesser amount of nitrogen per liter air that you breathe. Than in normal breathing air.

Another thing that can help out a bit might be that the air used for filling with oxygen to form nitrox is normally of a better quality since its filtered even harder than normal air. (this however depends on place of filling)

Another in short: you dont go deepeer on nitrox than air since you risk worse conditions than nitrogen narcosis. some of wich you cant even prepare yourself at.
such as CNS toxicity.

To "go deep" you would choose blends such as trimix, heliox or helair if possible. in the earlier days even air was used, but never nitrox, due to the toxic nature of oxygen at depth.

Dive safe
Dive within the MOD.

 

[devjr]

I'm fairly certain that there is a level of variability in nitrogen narcosis not represented by the information in Hobb's post above. In the course of deep diving(below 130')I've experienced some things such as visual distortion and difficulty with mental concentration but never the "martini" type conviviality or "rapture" often reported.

It was a long time ago, I was very young, about 10 yrs old, but I remember it like yesterday. I had to undergo extraction of a tooth and because I balked at the needle the dentist placed a mask over my mouth and nostrils. The progression of effects from the nitrous oxide is still clear in memory. I never became giddy or had any laughing gas effect which is so roundly joked about. There was no pain killing effect from the anesthesia that I could descern. There were distortions of my vision and a general "other worldly" feel.

Some years later, these exact effects returned as if in a dream. No, it was not flashback; the weirdness I had experienced in the dentist chair was once again my companion as I descended below 200 feet.

As to alleged anesthesia, I believe that a tooth extracted at that depth would hurt just as much as that day so many years before. To me, narcosis is more like a mushroom than a drink.

Draw your own conclusions but the there may be a broadly applicable parallel between the two gases. Moreover, if this be true, then somewhere there should lay an old study of the variability of effects and side effects of laughing gas. My gut feeling tells me that is where the true nature of narcosis also lies. No single rule for everybody.

The notion that one may not be aware of danger while under narcosis is possibly true. However, it is not true in my case. Under no circumstances have I ever been less than acutely aware of the progression of effects. A lack of awareness does appear to subvert the minds of some deep divers. In one of the ironies of my diving career, I was a witness to an appalling event; a narced SCUBA diver unexpectedly swam over the wall straight down to 300 feet and beyond despite efforts by others to catch up and turn him around. He never returned. The diver, who perished at Cay Sal Bank in 1976, was a dentist.

 

[simon66]

Originally posted by Hobbs


Since no one in their right mind would ever go deeper on nitrox than on air

Dear Hobbs ,
I never stated in any of my posts that i or anybody should or would dive deeper on nitrox than is possible on air .
What i refer to is the equivalent air depths
i.e a dive to a max depth of 40 metres on a Ean 32 mix at a ppo2 of 1.6 for a max time of 45 minutes would give you an equivalent air depth of 33 metres .
Also since the narcotic effect of nitrogen end is 4.0 bar on air this dive would be 3.95 bar and on a nitrox 32 it would be 3.4 bar so the nitrogen loading is slightly less.
so doing this dive would have a similar narcotic effect as a dive to 33 metres . Also giving a the same no stop dive time of a dive to 33 metres .
simon .