Oxygen and narcosis

[Dr Deco]

Hello readers:

Air Hunger

Oxygen usage by sports teams is more psychological than anything. [However, psychology is a big factor in sports and the perceptions by the players can be important.]

Your body is seldom if ever starved for oxygen. Carbon dioxide buildup is what creates the feeling of “air hunger.”

Dr Deco :doctor:

 

[pipedope]

Hello readers:

Air Hunger

Oxygen usage by sports teams is more psychological than anything. [However, psychology is a big factor in sports and the perceptions by the players can be important.]

Your body is seldom if ever starved for oxygen. Carbon dioxide buildup is what creates the feeling of “air hunger.”

Dr Deco :doctor:

You can prove this to yourself very quickly with a pulse oximeter.

This is also why training in good deep breathing technique often produces large improvements in performance. Along with some good self hypnosis, suggestion and anchoring with the breathing to set the desired mind state for best rfesponse.

 

[WarmWaterDiver]

Can you describe the dive where air is used as bottom gas and then you switch to Tx 50/50? I can't imagine.

There are certain issues with switching from nitrogen based mixes to helium based mixes (deep tissue counterdiffusion). I hope Dr Deco will give precise explanation.

Well, I can give you the profile for tech training dives if you have the appropriate software to examine the file. A tech cert training dive to 150 fsw, with switch to 50/50 at 60 fsw. Bottom gas was 25% EAN, which although not air, is exactly half the O2% of the 50/50.

But if one wanted to experientially try something as both Lamont and I posted, one could even use 60 fsw as the bottom depth if desired, and air as the back gas to see what the percieved difference is.

My imagination is fertile. It's regularly exercised.

 

[MonkSeal]

Well, I can give you the profile for tech training dives if you have the appropriate software to examine the file. A tech cert training dive to 150 fsw, with switch to 50/50 at 60 fsw. Bottom gas was 25% EAN, which although not air, is exactly half the O2% of the 50/50.

I have GAP (1.2 for PC), GAP-RGBM (Pocket PC), V-Planner (Pocket PC) and DecoPlanner (PC).

I would realy like to hear resonable explanation for using EAN25 as bottom mix and then switching to Tx 50/50. Switching from N2 based mixes (like EAN25) to He based mixes (like Tx 50/50) brings in some problems. I don't want do discuss using N2 based mixes at 150 fsw it's completely different issue.

 

[WarmWaterDiver]

Monkseal,

Ah - you mistake the abbreviation 50/50 from my ANDI tech training to indicate helium is present. In fact, the mixture is 50% O2 and 50% N2. This is exactly what we used. Would it be clearer if I used the term 50% O2 EAN for you? Note this is what Lamont used and I quoted, and you appear to be the only poster interpreting my post as a different mix. As I have posted previously on this board, I am not certified nor trained for mixes including He, nor do I dive with such mixes.

I am curious on your part to explain what standards exist that say a gas mix termed 50/50 must be interpreted to have helium in the mix? I thought the convention was to list three numerical values when that's the case - even if one of those values is zero. You added the letters Tx which were not present in my post.

Hopefully, this clears up your misunderstanding of my post . . . and maybe you can offer better explanation for yours in return.

 

[padiscubapro]

I have GAP (1.2 for PC), GAP-RGBM (Pocket PC), V-Planner (Pocket PC) and DecoPlanner (PC).

I would realy like to hear resonable explanation for using EAN25 as bottom mix and then switching to Tx 50/50. Switching from N2 based mixes (like EAN25) to He based mixes (like Tx 50/50) brings in some problems. I don't want do discuss using N2 based mixes at 150 fsw it's completely different issue.

Nothing he stated indicated he had helium in the mix.. the correct way to indicate 50% Helium and 50% oxygen is to call it Heliox 50 or HX50 for short.. The worldwide industrial/commercial/militray standard is to list the Helium % first in this designation.. so Heliox 80 would also mean 80% helium 20% oxygen.. The us Navy and other ops also extends this to nitrox as well to the US NAVY, NX60 is 60% nitrogen 40% oxygen..

The post should have been a bit more specific.. ANDI always suggests all components be clearly identified..
The poster should have called it SafeAir 50 or EAN50, or nitrox 50/50. ( if he wanted to use the nitrox designation say for 32% Oxygen, Nitrox 68/32 would be acceptable), whereas EAN50 and safeair 50 cleary show its not against commercial/mil standards..


for example the designation 21/35 means absolutely nothing without clarification.. Most people in the recreational diving world (eg non commercial/military) understand this poor choice of designation.. at least putting it as Tx21/35 gives more meaning and identifies its the arbitrary standard adopted my many in the early 90s..

 

[WarmWaterDiver]

Ah, my error evidently, this was common term used by my ANDI instructor (50/50) for 50% O2 / 50% N2 during our TSD-3 training. EAN50, SafeAir 50, etc. all work for me as well... Since Lamont had already used EAN50 I could have copied that, but copying Lamont's post into mine I thought helped keep the train of thought.

So why would He in my post be assumed in the mix?

 

[MonkSeal]

Nitrox 68/32 would be acceptable

I've never seen such notation. Every notation I know states the O2 first and the reason is obvious: Oxygen defines MOD. IMO indicating inert gas first (especialy N2) doesn't make any sense.

 

[WarmWaterDiver]

Monkseal,

If it's 50/50, such as I posted, how do you know the inert gas is first or second???

How does that possibly matter for 50/50 in my post?

And, the point of my post was to use two gases neither of which contain He, unlike what Lamont suggested, to take the He effects out of the picture.

I'm still at a loss . . .

 

[padiscubapro]

I've never seen such notation. Every notation I know states the O2 first and the reason is obvious: Oxygen defines MOD. IMO indicating inert gas first (especialy N2) doesn't make any sense.

Not to be sarcastic but do some reading..

Oxygen is not the most imporatant to many folks its the inert thats inportant since it defines what your decompression schedule is required..


Read some commercial manuals, or better or even the US navy manual( its available free online) .. look at chapter 17 for the most examples..They always list Inert gas first..

Its not oxy Heil,or oxy ni,, its heliox and Nitrox..

The designaition adopted by many in the recreational world was arbiraty, and doesn't follow any of the adopted standards.. Oxygen first is NOT a standard in the DIVING industry, just by many in the recreational world (meaning non commercial, non military).. The naming many are using came in the early 90s, Naming protocols have existed since the start of commercial and military diving.

But still hm saying 50/50 has no basis to assume its a helium mix..
all it says is that there are 2 gases 50% each,

Heliox is always referred to by name (its just that some groups name it wrong)

Here are a few links to start your education..

http://www.coralspringsscuba.com/usn/Chap10.pdf
http://www.coralspringsscuba.com/usn/Chap15.pdf
http://www.coralspringsscuba.com/usn/Chap14.pdf