Oxygen Toxicity vs Narcosis

[rjack321]

I personally am skeptical that this was really a OxTox induced seizure.

She was clearly seizing, of course the cause of that seizure we'll never know since there's no smoking gun (e.g. breathing 100% at 150ft)

 

[limeyx]

I personally am skeptical that this was really an OxTox induced seizure.

Right, I dont think we will ever be 100% sure on this one.

However, from my understanding it *was* a seizure induced by something (medicine, pure bad luck/chance, or O2)

The embolism is just a side-effect since the seizure continued so long that the rescuer was forced to ascend the victim with a closed airway.

Very sad story.

The moral (for me) is that there isn't much benefit to pushing PPO2 on the "working" part of the dive, and it's really hard to survive a seizure, so I really aim to keep it low, and then only bring it up on deco.

 

[Rick Murchison]

Seizure at 1.4 ppO2 3 weeks ago. http://www.divers4life.com/TheCrack.html
Never say never.

I've read it. I don't believe this was an oxygen hit at all..
Rick

 

[Rick Murchison]

... the seizure continued so long that the rescuer was forced to ascend the victim with a closed airway...

Not an oxtox type seizure, which are brief, as seizures go. I do not believe this was an oxtox seizure.
Rick

 

[biz_nate]

Charlie, that report was an interesting read. Thanks for sharing.

At least with oxygen, there's a reason it doesn't accumulate like nitrogen, as oxygen is both metabolized in all the tissues, and scavenged by hemoglobin from the blood.

In my (admittedly, very) limited understanding, oxtox is in fact an accumulative process. O2 most certainly is metabolized by tissue much more quickly than N2, but I thought that the concern with oxtox is buildup of free radicals? That would explain why 1.4, as you cited, could be the magic number- below this, ppO2 is low enough that O2 in the bloodstream is readily metabolized.

At any rate, I agree that nausea can be brought on by many things- in this case, oxtox would be pretty low on my list of suspicions as well.

Sometimes people break profile. Though I don't like to admit it, I've done it too. Half the reason we come up with plans, though, is so that when something (like nausea) does happen, we don't have to ask questions like this. I'd much rather be confident that my nausea has nothing to do with O2 and keep diving, than be forced to question whether it's safe to continue that day.

 

[limeyx]

Not an oxtox type seizure, which are brief, as seizures go. I do not believe this was an oxtox seizure.
Rick

And you have obviously the right to believe that with equal weight (at this point) as the people that think "what if it was, maybe I should lower my working PPo2 since at those depths, I really dont get a significant advantage out of the higher PPo2"