Oxtox: Seeing it 1st hand

[Slamfire]

Who do you want to discuss oxtox symptoms with, someone who's seen it first hand, or someone who read about it in a book once?

Has anyone in this forum seen oxtox symptoms firsthand? I remember diving with a very experienced diver once who explained to me that he always planned his ppO2 (open circuit) for 1.6 at the bottom. His theory was that he had seen a lot of people bent, but he had never seen someone tox, and he had never known someone who had seen sometime tox.

I haven't either, and from his comment I assumed it must probably be a very, very rare event?

I think it is a very, very rare occurrence, but if it happens there is a very high likelihood of drowning (obviously depending on specific circumstances). Let's face it, it is very common to survive a DCS hit. I don't believe the same can be said of oxtox.

I know Wayne - aka DCBC - survived an oxtox hit. I've been meaning to ask him about it. What does it feel like? Any recollections as he emerged from unconsciousness? And not to be morbid or suicidal (I promise I'm not; I love life) would it be a good way to die?

Because of the morbidity I've always hesitated to post these questions in an open forum. Perhaps this is a better forum to discuss. I read this story at a SB member's personal website. It's about a rebreather diver that got silted out in a wreck.

But here, faced with the horror of knowing I likely would never find my way out I imagined with growing repulsion the thought of desperately scrabbling around the wreck, blind in the zero visibility for hours just waiting to die. My thoughts then turned to a quick escape. I pondered fleetingly about taking my own life, I wondered to myself momentarily if it would be better to drown than to spend fruitless maddening hours blindly stumbling around the silty labyrinth in vain. If I were to drown myself how would I do it? I decided I would come off the rebreather and just take one big mouthful of water. Would it hurt? Would I lose consciousness immediately? Drowning myself I reasoned might be better than the slow maddening torture of waiting to die here.

As I read the above quoted passage I thought, "well, why wouldn't he go to a very high FO2 and tox out". From what I've read, it would probably be more comfortable than gulping in water consciously.

Again, I'm not suicidal, and I'd like to think of myself as someone who does not give up easily. But if I were given the choice to die after I've lost my mind (eg. alzheimers), bedridden with uncontrollable bowels, etc. versus dying while relaxing underwater 500 ft under doing something I love to do, well... At least if I am to oversimplistically consider only those two variables without taking into consideration other more complex factors like the suffering I might cause my family, the choice is clear.

What do you guys think?

Could we invite Wayne in to share his thoughts on this if he wishes to?

 

[Cave Diver]

I've been witness to a suspected Oxtox event. And I say "suspected" because without running tests, I dunno how you'd say with certainty. That's just based on my observations of the events.

About 10 years ago, on a warm water vacation. Several of us were doing some deeper wall diving. I was among the least experienced at the time and this dive was done on air. One of the more experienced guys decided he was going to go deeper. I dropped down a little way with him, stopping when I hit my comfort level. He continued on down to ~254' IIRC correctly.

I watched him descend and then my attention was caught by a huge lobster hiding inside the middle of a 4' barrel sponge. This was probably around 180'. The next thing I remember was hearing this strange quacking noise. I looked around trying to identify it and see a solid stream of bubbles coming up from the wall and the other diver ROCKETING up. I moved to intercept him, got a hold of his BC and the ascent was arrested around 150'. He'd burned through an incredible amount of air and I shared air with him until we got back to shallow water and he went back on his own tank.

The noise I heard was his OPV burping. Talking with him after the dive he said everything was fine. Then he started hearing wah wah's and he lost his vision. Said it was like someone turned off a switch, or put a mask over his eyes while clapping your hands rapidly over your own ears. He felt like he had to get out of there NOW! and the last thing he recalls was reaching for his inflator. No recollection of actually hitting the inflator, ascending, or anything until I grabbed a hold of him.

Oxtox? Deepwater blackout? Narcosis? Something else? I dunno for certain. Visual and audio disturbances led me to think he was on the verge of an oxtox event. I never saw him convulse and he never spit the reg out.

That experience was his last venture with diving deep and what convinced me to pursue tech training.

 

[TSandM]

slamfire, I've actually thought about the same thing. I have a bad family history for Alzheimer's, and don't want to end up in a nursing home drooling on myself. Taking a 40 of O2 for a swim doesn't sound like a bad end to things. If you seize, you are unaware of what's going on while you are seizing, and are usually not very responsive immediately afterwards. How aware you would be of taking that first breath of water, or of drowning, I don't know -- but you would certainly be less aware than you would be under normal circumstances. If you set the whole thing up to be pretty badly narced at the same time, you would definitely have some anesthesia for the whole drowning event.

 

[Cave Diver]

I just spoke to the other person about this story and he related some more thoughts that I either didn't know at the time or forgot.

First off, he said that the only reason he felt he didn't lose the reg is because he had a Seacure mouthpiece. Without that, he's convinced he would have lost it. The visual disturbance was a bit different than I recalled. He said his vision was kind of like a kaleidoscope. It started off with everything looking swirly and then it would fade in and out. Every time he felt his heart beat vision would narrow down to a pinpoint, then open back up.

He also remembers having a narcotic conversation with himself.

I need to get out of here.
How?
Go up.
How am I gonna go up?
Push the button.
What button?
Your inflator button.
Oh. How am I supposed to do that?
With your hand.
I have hands???

He said he never did get his hands to work. He ended up pressing the catching the inflator between his forearms and basically "hugging" himself. Hearing the popping noise from the OPV was the last thing he remembers til I got to him. After I made contact and he was responding to signals he remembers looking at his gauges with no recollection of actually hitting that depth and looking at his gauge and going Holy Sh!t because he was down to almost 500 psi. At this point his vision had returned, but he still had a slight ringing in his ears.

The conversation with him reminded me of another experience I had. My buddy and I were on a mix dive and had just started to head back up. I observed a diver much deeper that appeared to be moving erratically. After a brief debate, I decided to go down and check on them. He was deeper than my planned depth and my Po2 ended up being much higher than we'd planned for that mix. I recall starting to hear a ringing in my ears and getting a strong metallic taste in my mouth. Somewhere along the line, I remember hearing that as a sign of oxtox as well. As soon as I determined the other diver was ok, I got the hell out of dodge and did some extended deco to make up for the schedule deviation. My symptoms cleared by the next deco stop.

 

[rjack321]

I have experienced oxygen toxicity. In a chamber at ppO2 of 3.0 I was puking my guts out every 18mins. (the 2nd "N" in CONVENTID is for nausea). I could set my watch by it. It subsided on the 5min air break and returned near the end of the next O2 session. And it continued once we'd ascended to 30ft.

It was really annoying and made staying hydrated difficult as the only food and drink you can take in are when the hood is off on the air break, when I was still wretching.

I think people overemphasize the "convulsions" part of the signs and symtoms of CNS toxicity, I have seen dizziness and facial twitching in the water in a buddy on deco as well. It was late in 20mins of deco and we surfaced uneventfully.

 

[Cave Diver]

I think people overemphasize the "convulsions" part of the signs and symtoms

I agree with that. I think some of the other symptoms are more likely to manifest first and be noticed if the person is aware enough to notice them.

 

[Slamfire]

I think people overemphasize the "convulsions" part of the signs and symtoms of CNS toxicity.

I hadn't thought about it, but you're right. I guess I just dismissed the other symptoms because they are too close to narcosis. Put them out of sight out of mind and focus only on convulsions. It would suck to head out on the final peaceful swim only to have to abort it because you can't stop puking.

 

[denisegg]

My buddy and I went to Hole in the Wall on a pontoon boat not long after I received my Intro Cave cert. We came upon two divers who had just finished their dive there and one of the guys was pretty freaked. We was back several hundred feet on the gold line when he began to have tunnel vision. He turned the dive and as he and his buddy made their way back his vision came and went. He said he would almost black out and then the tunnel vision would return. This was his first day of a week long diving trip from out-of-town. He was pretty shook up but sat there contemplating whether he would try diving again the next day. But he wanted to talk to some one who had had a reaction to 02 to see if his symptoms seemed to indicate an oxtox episode. It had never happened to him before. I don't know what mix he was using and since we were only there for a couple of days I never got to talk to him again.

 

[gkndivebum]

[...]I think people overemphasize the "convulsions" part of the signs and symtoms of CNS toxicity[...]

Agreed; I was involved in the management of a CCR failure recently that manifested itself initially as extreme
nausea. We got the diver off the loop and onto open-circuit bailout quickly and without escalation of the symptoms.

I believe that this diver was very fortunate.

 

[Rhone Man]

I've been witness to a suspected Oxtox event.

<snip>

He continued on down to ~254' IIRC correctly.

I assume you guys were breathing EAN 21? I remember JC once saying that he had never heard of someone toxing on air (when talking about the Feldman death on U-869) and I have always had a vague belief that ppO2 is not the only determinant in toxing - absolute percentage of O2 played a part (hence why people can set staggering 'deep air' depth records without toxing).

Not saying for sure your friend toxed - as they say, a lot of the VENTID symptoms also reflect advanced narcosis symptoms. But just throwing it out there.