Is nitrox "briefing" enough without certification?

[Snakekid97]

Hi all,

I have a basic OW certificate with about a dozen OW dives. I recently moved to a coastline, but I haven't gone diving in the ocean in about a year (although I have done a couple of quarry dives since). I recently talked to a local PADI instructor/dive charter owner about easing back into things. After scheduling a date to go out on his charter, I found out they only use nitrox on all of their dives. They claim it's the better way to dive. Their website states " If you are not Nitrox certified, don’t worry, we will give you a Nitrox Briefing that lets you dive Nitrox that day...We will also put a _ Dive Computer on your wrist set for 32% so you can track your NDL."

I have read that I should have a certification for nitrox (which I don't have). My question is: would you trust a "Nitrox briefing that lets you dive Nitrox that day" or does this seem to be a questionable practice? I have no prior experience with Nitrox.

I should add, the charter is a 2-tank trip on reefs 40-60' deep over about a 3-hour period.

Thanks!

 

[L13]

Not if oxygen is equally narcotic as nitrogen. Which is more or less current thinking, as far as I’m aware, though research is probably not conclusive. (I don’t think we fully understand the mechanism behind gas narcosis.)

Actually, current research suggests it it significantly less narcotic than nitrogen.

 

[L13]

Here is one post quoting Simon Mitchell.

Oxygen narcotic?

EAN32 is more narcotic than air. Oxygen is more narcotic than nitrogen. Choosing EAN32 to reduce narcosis will not work. Splitting this off from another thread because of curiosity. I'm in the middle of doing a TDI trimix class, because helium! But one of the slides in the powerpoint we were...

scubaboard.com

It seems like half the people in this thread refuse to read that link. Either that, or choose to ignore it.

 

[azstinger11]

I have always wondered if the experience of narcosis while diving is somewhat dependent on previous encounters with the feelings and alterations.

After all my altitude chamber training for hypoxia in the Air Force, I’m pretty keenly attuned to when my body/mind starts acting funny. Maybe it’s being trained to notice or exposure to altered mental states but I can absolutely tell. Yes I’m fully aware gas narcosis does not equal hypoxia.

 

[boulderjohn]

It seems like half the people in this thread refuse to read that link. Either that, or choose to ignore it.

What happens in situations like this is really common throughout all activities. A concept has become thoroughly established, and people in general are very familiar with it. When a question arises, they confidently post the old, established information and don't even look at anything anyone else writes. It's human nature.

 

[wetb4igetinthewater]

It seems like half the people in this thread refuse to read that link. Either that, or choose to ignore it.

Is a comment of I stand corrected necessary? I've made multiple comments where I have clearly stated where I look to Dr. Simon Mitchell for guidance.

It would be arrogance at an unprecedented level to think I understand dive medicine better than him. I simply follow his guidelines until he/science changes them. He is conservative in his advice and makes sure the science is solid before making those recommendations.

 

[L13]

Is a comment of I stand corrected necessary? I've made multiple comments where I have clearly stated where I look to Dr. Simon Mitchell for guidance.

It would be arrogance at an unprecedented level to think I understand dive medicine better than him. I simply follow his guidelines until he/science changes them. He is conservative in his advice and makes sure the science is solid before making those recommendations.

I was just noting that even after the article was posted, several regulars continued to state that current thinking was that oxygen is as narcotic as nitrogen, which is false. It was like they hadn't read the rest of the thread or the linked article which has now been posted 4 times in the thread. No need to make a "stand corrected" post, just don't post old info after new is already in the thread.

 

[jborg]

Well, I stand corrected.

 

[Angelo Farina]

I have always wondered if the experience of narcosis while diving is somewhat dependent on previous encounters with the feelings and alterations.

It is strongly dependent on how long you was not diving.
I usually got a strong hit at just 40 m in the first dive of holidays, after months without diving.
The following day I became progressively more tolerant, and after one week divingv rgularly each day, I started to be narched obly if going to 55-60 m.
Note that I never pushed it too hard. As soon as some narcosis was building up, I ascended a few meters (mostly they were vertical walls woth Paramuricee and red coral and lobsters, so ascending a few meter was meaning remaining close to a wonderful wall).
So previous narcosis episodes does not make you more sensitive, instead they make you more resistant.
But this resistance fades away if you stop diving for some months.
Sorry for derailing this topic about narcosis.
It was originally about Nitrox at very shallow depths, where narcosis is not a concern.
And in my experience (me, my wife, and divers under our responsibility) the bad narcosis hits, the unpleasant ones, were always triggered by CO2 accumulation, not by nitrogen or oxygen...
Ot by bad envirnmental conditions: my worst hit was in Lago Msggiore at just 24m: it was cold, dark, low visibillity, the water was brown, and I was being examinated for my *** CMAS instructor degree, so I was under stress.

 

[Angelo Farina]

I was just noting that even after the article was posted, several regulars continued to state that current thinking was that oxygen is as narcotic as nitrogen, which is false. It was like they hadn't read the rest of the thread or the linked article which has now been posted 4 times in the thread. No need to make a "stand corrected" post, just don't post old info after new is already in the thread.

I remain of my opinion: CO2 is by far the most relevant cause of bad narcosis episodes. Environmental conditions is the second one.
Not oxygen or nitrogen partial pressure...
Please note that most studies on narcosis are done inside an hyperbaric chamber, having subjects scored through computational tasks and by EEG.
No significant physical effort, no cold, darkness, low visibility, which are all factors severely affecting the insurgence of a "dark" narcosis.
Furthermore in these studies each subject is "reused" several times, without accounting with effect of increased resistance to narcosis which builds up dive after dive, and which takes months to fade away.
Hence I consider all of these studies conducted in the lab interesting, but inconclusive about what happens to real divers.
I trust these studies in lab conditions less than my experience underwater, where I experienced narcosis at least 50 times and witnessed it hitting other fellow divers perhaps 200 times and in very different environmental conditions.
Please note that I am a scientist.
I have direct experience on how tests involving human subjects conducted under artificial lab conditions can be misleading....
Particularly when trying to asses perceptions, emotions and state of brains.

 

[scubaozy]

I remain of my opinion: CO2 is by far the most relevant cause of bad narcosis episodes. Environmental conditions is the second one.
Not oxygen or nitrogen partial pressure...