Today I think i survived a CNS hit at depth

[Quero]

Glad you're feeling well now. Take care!

 

[pickens_46929]

Here's an interesting question... one that I don't think has been asked yet.

Were you taking any medication at the time? Nasal spray?

Even over the counter stuff or diet supplements can sometimes cause weird things to happen.

They didn't really say much. I plan to dive air or keep my pO2 below 1.2 until I get home and speak to some hyperbaric specialists.


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[HowardE]

Other important factors that could have effected the person were

1) What did you have to eat? The night before, and for lunch, since this was in the afternoon?

2) How hydrated were you when you made this dive?

--

I would be surprised if DAN could actually have anything to say since if it was in fact an Ox Tox hit (which I perceive as unlikely), there wouldn't be any lasting evidence of the Ox Tox episode to record data post dive.

While the diver did go diving previous days, his OTU's would have started at 0 for this dive, since it was more than 24 hours out of the water.

I'd be inclined to believe the diver was narced and cold, and most likely didn't suffer from an ox tox hit at 118 Feet on 28% Nitrox. As others have stated, there would be significant narcosis at that depth, especially for someone who has this as their deepest dive ever.

While the diver may have believed they were experiencing symptoms of CONventid, I'd have to agree with Lamont. Sounds more like panic and fear of the narcosis and possibly the significant drop in temperature. 5 degrees Celcius from 30C is the difference between 86F and 75F. This is significant. Perhaps also a fear of the fact that they learned about conventid, and in this panic moment thought, "Oh crap, I'm feeling conventid, I must be toxing" this would certainly increase the panic attack.

At any rate... Glad you pulled through, and this is certainly a good learning experience.

 

[vladimir]

I would tend to weigh the objective evidence (depth, time, mix, etc) more heavily than the subjective description of symptoms. While I would expect a trained observer to recognize a seizure fairly reliably, for example, I would not have the same confidence in a self-diagnosed one. Especially when diagnosed by a diver who knows his CONVENTID.

Glad you're okay, OzGriffo, and thanks for posting. That would keep me on dry land for a long time.

 

[H2O Gal]

Snip from Jim's post:

His buddy held him as he drowned. Could not get the reg back in. Your buddies being able to get you shallower may be the only reason you are alive.

Jim, your story is both touching and horrifying at the same time. This brings up a question-- if oxygen toxicity can be so deadly and the only treatment is to ascend, why risk using nitrox when cave diving? Is it a common practice? I understand the benefits, but I guess you have to decide if the benefits outweigh the risk....

 

[ianr33]

Jim, your story is both touching and horrifying at the same time. This brings up a question-- if oxygen toxicity can be so deadly and the only treatment is to ascend, why risk using nitrox when cave diving? .

Couple of things here.

Nitrox greatly reduces the amount of deco needed. An hour at 100 feet (pretty typical Florida cave profile) needs around 35 minutes deco using air for the dive and O2 at 20 feet for deco. Do the same dive on 32% and the deco is only around 12 minutes. On long dives not using nitrox could result in hours of extra deco.

If someone is having a full on oxygen induced seizure they SHOULD NOT BE TAKEN SHALLOWER. Their airway will be close and ascending will cause lung damage and likely death. Procedure is to wait until the seizure subsides, try and make sure the diver has a reg in his mouth, then ascend. Not many divers have survived an underwater O2 seizure. Need an excellent buddy and a lot of luck IMHO. Hope it's something I never come across.

 

[boulderjohn]

I certainly would never ever want to do a deep dive again with anyone who is not Rescue trained.

Rescue Diver does not teach the procedure for surfacing a toxing diver. In fact, as this posts implies....

If someone is having a full on oxygen induced seizure they SHOULD NOT BE TAKEN SHALLOWER. Their airway will be close and ascending will cause lung damage and likely death. Procedure is to wait until the seizure subsides, try and make sure the diver has a reg in his mouth, then ascend. Not many divers have survived an underwater O2 seizure. Need an excellent buddy and a lot of luck IMHO. Hope it's something I never come across.

...using the standard technique for surfacing an unconscious diver can be a serious mistake. A diver in a full tonic/clonic seizure goes through three phases, one of which is sleep. If the diver has a working air source in the mouth, it is safe to ascend during the sleep phase. As stated above, it is not safe to ascend during the tonic/clonic phases. Note, too, that the sequence can begin again during the ascent.

It is indeed rare for such an ascent to be done successfully but it has been done. In fact, I suspect it has been done successfully more often than surfacing an unconscious diver has been done successfully. Here is a video showing the process. SCUBA: Rescuing a Toxic Diver - YouTube

 

[rhwestfall]

On another note, I measured my SAC for the dive. It was actually lower than normal at 13l per min averaged across the dive.

this little tid-bit may show as an unusual breathing pattern, hence CO2 loading..... perhaps another clue. Glad it all came out for the better!

 

[Griffo]

Although I would tend to lean toward a combination of a CO2 and Narcosis problem there still is a possibility of a O2 hit. Did you take any kind of medication that day? There are some meds that will tend to lower O2 tolerance.

Actually I did use an antiseptic cream and some spray on bandage for the first time just before that dive..

And just to clarify, I have been deeper, I have been in colder water, I have been in lower vis, and I did not feel at all panicked.

I know what I feel like when I am getting stressed, I was not all all stressed. Besides isn't panic defined as the loss of reason and logic? I think I was remarkably calm and logical. If I was panicked I would have bolted for the surface right??

While we were swimming into current, it wasn't a massive effort, The reason I was at the back was that I was deliberately pacing myself and just kicking and gliding rather than finning flat out.

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[boulderjohn]

And just to clarify, I have been deeper, I have been in colder water, I have been in lower vis, and I did not feel at all panicked.

What you describe is unusual enough that I doubt anyone can say anything with certainty. The topic is quite interesting, though, so speculation and discussion can be valuable.

A friend of mine is a tech instructor, so he has a lot of deep diving experience. He knows that narcosis is always present to some degree on deeper dives, but like many people he usually does not consciously feel its effects. What he describes as his most obvious example may be helpful in this case.

He was not particularly deep--only 85 feet. It was a relatively benign environment--just a routine dive. He suddenly felt a wave of panic come over him. He felt a tremendous dread, a fear that seemed to have no cause. But he was able to think analytically, and he decided it must be narcosis. He calmly ascended about 15 feet. The rest of his group was puzzled and joined him, asking if he was OK. He very soon was OK. He soon felt better, and they went on with the dive with no more effects.