Scuba Nitrox Incident for Analysis

[wnissen]

I wonder if it is CO2 contamination. It takes a while to build up, would go away in large part if you get shallower.

 

[JohnN]

Please don't confuse partial pressure with FG.



I'm confused as to why if you are admitting it's unlikely the answer that you would bring it up in the first place? Again, one of his lungs spontaneously disappearing and then reappearing could fit these symptoms but it's unlikely to be "the answer".

FG? Help me out, what are you referencing?

 

[OTF]

On the first post in the video, the guy sets a hypothetical scenario. There’s lots of possibilities for causes, one could be a PFO. That’s all.

Another equally intriguing possibility could be alien lung parasites awoken from deep-sea dormancy invading their first victim.

 

[John C. Ratliff]

How's your buddy? Is he OK? Was he having a heart attack or something? How long had it been since his last dive, before preparing to dive with you that day?

My buddy was okay. Once out of the gear, he told me that he had done nothing since the pandemic shutdown, not ever going out for a walk. What wasn’t explained in the video was that he had just walked back up to his car and back down, about 200 yards, with his twin 72s and full weight belt on. He did not take his time getting into the water, and was out-of-breath when he jumped in. He had forgotten to bring down his mask. I was concerned that he had contracted COVID-19 too, so he talked with his doctor and after several days got tested—negative. So it was solely lack of exercise for several months.

SeaRat

 

[John C. Ratliff]

I'm wondering the same thing. That looked like a cardiac event to me. I don't want to hijack the thread, but @John C. Ratliff maybe you could make another post.

No, it wasn’t a cardiac event. We actually concluded it was him over breathing his modified double hose regulator (it is a condition noted in the U.S. Navy Diving Manual; I’ll have to look up the specifics on it). If you watch the video again, count the number of respiration per minute. He started out with an oxygen debt (see my prior post), did not rest enough, and then was breathing fast and shallow.

SeaRat

 

[RainPilot]

I've heard that theory, but riddle me this, a rebreather dive can be at a PPO2 of 1.4 in 15 feet of water. If the concentration of O2 in what your huffing can be linked to narcosis, then why are rebreather divers not always loopy? I know, I know, hold off on the cheap and obvious joke. . .

It's about the total partial pressure of all narcotic gases. At 5m, the total PPnarc would be 1.5 (if assuming O2 is narcotic, which there is a fair bit of evidence to support but not a certainty)

At 30m, it is generally agreed that narcosis becomes significant, so if diving air, a PPN2 of 3.16 and a PPO2 of 0.84 so either way you look at it, a PPnarc of greater than 3.0 or possibly 4.0 if we consider O2 to be narcotic (I do, for purposes of planning and conservancy)

Generally, I try to keep my PPnarc below 4.0 (including O2) wherever possible, and often find that gas density guidelines drive the gas selection process more than the narcosis numbers.

 

[Celt]

No, it wasn’t a cardiac event. We actually concluded it was him over breathing his modified double hose regulator (it is a condition noted in the U.S. Navy Diving Manual; I’ll have to look up the specifics on it). If you watch the video again, count the number of respiration per minute. He started out with an oxygen debt (see my prior post), did not rest enough, and then was breathing fast and shallow.

SeaRat

Felt sorry for your buddy he got caught in a perfect storm. His trim was putting him on his back and it’s harder to clear a twin hose single stage like that. Lot’s of lessons in your video. Thanks for posting it.

 

[Angelo Farina]

No, it wasn’t a cardiac event. We actually concluded it was him over breathing his modified double hose regulator (it is a condition noted in the U.S. Navy Diving Manual; I’ll have to look up the specifics on it). If you watch the video again, count the number of respiration per minute. He started out with an oxygen debt (see my prior post), did not rest enough, and then was breathing fast and shallow.

SeaRat

He did not start with "an oxygen debt" (hypoxia), he started with a lot of CO2 in his blood, causing him a "short breath" (Hypercapnia). It is not the same thing, albeit you seem to confuse the two concepts. But a visual look separate them easily:
- hypoxia your skin is pale, you are weak, and you are not over-breathing
- hypercapnia you skin is red or even blue, and you breath very quickly.
In the video, his face is quite pinky!
Carrying a weight over a slope causes a lot of CO2, but does not burn too much oxygen...
All what happened later just made the CO2 retention to worsen...
But going deep provided him with A LOT of oxygen, which did not improve the situation, of course, as lack of oxygen had never been the problem.

 

[Bazzathemammoth]

One of my good mates got diagnosed with PFO. The doc was amazed that he hadn't been bent.

Unfortunately that was the end of scuba for him.

PFO (Patent Foramen Ovale) -- AKA hole in the heart.

Stopped many a diver from diving and causes various DCI.

 

[Julius SCHMIDT]

So it was solely lack of exercise for several months.

The no bc broke the camels back John C. Ratliff, and even the dumb snorkel that he thankfully didn't use
See there it is a guy starting to drown in still flat water, doesn't dump weights, no need to wonder what happens to divers in a moving ocean
I used to dive no bc before the bc didn't like it, still don't like it can do it to show off but it's too much work, dangerous.
Thank you.