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!

 

[jborg]

Hey Marie..... Not sure I fully understand why Nitrox would not help with narcosis.. If a diver goes to 110ft on air and experiences some level of Narcosis from breathing 79% nitrogen..... wouldn't that same diver have most likely experienced less narcosis if they were breathing 68% nitrogen?

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.)

 

[Marie13]

Hey Marie..... Not sure I fully understand why Nitrox would not help with narcosis.. If a diver goes to 110ft on air and experiences some level of Narcosis from breathing 79% nitrogen..... wouldn't that same diver have most likely experienced less narcosis if they were breathing 68% nitrogen?

We’ll let someone else have at who can explain it a hell of a lot better than I can. I’ve been at 115ft on 20% helium. The difference was astounding. I’m narced out of my gourd at 130ft.

 

[Angelo Farina]

We’ll let someone else have at who can explain it a hell of a lot better than I can. I’ve been at 115ft on 20% helium. The difference was astounding. I’m narced out of my gourd at 130ft.

Nitrogen, oxygen and CO2 are all narcotic at high pressure.
Helium instead has the opposite effect, it is depressing.
Balancing the two effects, a proper trimix mixture provides not narcotic, nor depressing effect.

 

[NW Dive Dawg]

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.)

Yeah..... sorry about that. I think us old folks just naturally assume that when we are talking narcosis and diving...that we are talking about Nitrogen Narcosis.

 

[wetb4igetinthewater]

People may be interested in this table taken from: Moving in extreme environments: inert gas narcosis and underwater activities

 

[tursiops]

Hey Marie..... Not sure I fully understand why Nitrox would not help with narcosis.. If a diver goes to 110ft on air and experiences some level of Narcosis from breathing 79% nitrogen..... wouldn't that same diver have most likely experienced less narcosis if they were breathing 68% nitrogen?

It is because it is "gas" narcosis and not "nitrogen" narcosis.

 

[boulderjohn]

I think I recall @boulderjohn having an anecdote on this.

I have in the past referenced a story I got from (IIRC) Bob Bailey, who used to go by NWgratefuldiver but has since moved to Mexico. In his version, when denied nitrox with a trimix card, he asked for a trimix fill of 32/0, and he was successful in making the guy realize the inanity of it all.

 

[boulderjohn]

People may be interested in this table taken from: Moving in extreme environments: inert gas narcosis and underwater activities

View attachment 785908

Recent studies have indicated a small benefit for narcosis when diving nitrox.

 

[wetb4igetinthewater]

Recent studies have indicated a small benefit for narcosis when diving nitrox.

Link? Peer reviewed?

 

[RobPNW]

I get that it is GAS narcosis, but is it based on what's coming in/out of the lungs in real time or does it depend on body accumulation? Hopefully, that makes sense. Reason I ask is because if it is heavily accumulation dependent, than it seems the N2% would matter since O2 metabolizes. I have never been narc'd but I guess the easiest answer to my question would be if a person is susceptible to this, are they immediately susceptible if they go straight to depth or does it get worse if they stay there? Again, hope that made sense