symptom of Ox Tox?

[SailNaked]

Recently I was diving with about 33% Eanx at about 85ft I started to lose hearing or at least my hearing changed. I immediately went up some and the sensation went away. I did not try to go back down to see if it was just water in my ear or a clearing issue. is that a warning sign of anything Nitrox related? obviously 85 ft is near the (rec) limit of 33% in a hand grenade sort of way but I had considered it totally safe as I have read that the Navy regularly uses 2.0PP as a limit.

 

[Rick Inman]

NOTE: I am NOT a doctor or in any way qualified to give medical advice, so take my opinions for what they are worth.

Assuming a recreational dive with one tank (meaning limited bottom time at depth), and at a PPO2 of 1.18 ([.33*3.57]-1), then I very much doubt that you were experiencing oxygen toxicity. Yes, a ringing in the ears, or change in hearing, can be a symptom of a hit. But there are other possible causes, including pressure on the ears, sinus congestion, etc. Heck, we all get ringing in our ears even on the surface sometimes.

The MODs set up by the agencies are very conservative when you add both time and PPO2 limits - the combination of both which lead to O2 issues - and you were well within them.

Still, IMO, did well to slowly move shallower and see if the symptoms disappear, or abort the dive if uncomfortable.

I would not use the Navy as a guide, though. Their guidelines assume perfect health and fitness, youth, and a decompression chamber at the site. The navy assumes and accepts higher DCS-per-dive incident rate than the scuba agencies.

 

[MSilvia]

I had considered it totally safe as I have read that the Navy regularly uses 2.0PP as a limit.

Unless you're familiar with and following the USN protocols for the dive, which I have to assume you were not having "read that" they use 2.0pp, I think any belief that you can violate 1.4 for a recreational dive "totally safely" is an extremely reckless assumption. I don't know what protocols they use, and I hope someone else will chime in here, but with a ppO2 that high, I'd have to suspect the surface support vessel would have a hyperbolic chamber available. In any case, stick to your training. Things you read but don't fully understand might get you bent or worse.

 

[vladimir]

The symptoms of oxygen toxicity that I was taught in an Advanced Nitrox class were Convulsions, Visual disturbances, Ear disturbances, Nausea, Twitching, Irritability, and Dizziness. The mnemonic they used--which I still remember 15 years later--is CONVENTID.

 

[Jim Lapenta]

In additon O2 Tox is not the same for every person. A diver who passed last year toxed at less than 1.4 last year in a cave. Some of us as a result of this plan for max of 1.3-1.35 on working portions of the dive. And since I do not have my advanced nitrox yet and use 40% max for deco I plan on 1.5 for that. O2 toxicity is still being studied and guidlines will continue to be adjusted. As an individual nearly 50, less than perfect shape, and with a family that needs me, it's prudent for me not to push the limits too far

 

[SailNaked]

Msilva -No i am not diving 2.0 and no I do not recommend 2.0, I only brought it up to say that 1.18 is a long way from 2.0.
I really did not want to hear that I was having any symptoms at this low number and well below 1.4, I will have to be careful and test this more. actually on that dive I was at 91 ft and having no issues it was a wreck so there was a bit of up and down at the depth when the hearing issue started I checked my depth noted 85 and went up and it cleared. I am an alcohol light weight so maybe I am also an O2 gimp.
N2 does not seem to bother me much at 110.

I am about to take Adv Nx/Deco so I think I will practice some 1.0-1.4PP first.

I am also more conservative now that my children would be real mad at me if I did not provide adequate college funds. They would not miss me, but they would be mad.

 

[NJDiver07866]

Even the best of us can get a little buzzy and 'gas narcosis' can happen at those depths... Some people argue less nitrogen means less narcosis, others say oxygen is also narcotic so now the people call it 'gas narcosis'. Call it what you may, but even if you follow all the 'rules' I have experienced some really wonky things, so my .02 cents is you did the right thing, if something wonky happpens just thumb the dive...

Could have been all that loud greatful dead music you listened to as a kid... or a million other things..

If you look at the research oxygen exposure is all over the board. Do some google searches on J.S. Haldane and read about chamber dives with 7P02+ with no issues and others that tox <1P02. Where the safe line is? Who knows....

Some instructors will give you the tables like they are 'law', but the bad news is, they are more like a soft science. That's why when I teach folks, I let them know the risks. We came a long way in understanding pressure on the body, but the only sure way to stay safe from dive related injuries is stay out of the water. Just like the Jedi, you cannot think in absolutes when it comes to diving, don't cheat the table, but don't be upset when the table bites you, because its just a matter of time until it does. You dive long enough Wonky things happen...

Dive safe

 

[Puffer Fish]

How absolutely sure are you of the 33% number? Might want to do a double check...not that it is wrong... but we tend to assume everything was working correctly..

 

[Dr Deco]

Hello SailNaked:

I cannot say whether this is oxygen toxicity or not, but it should be remember that the appearance of this problem is high variable in one individual.

Oxygen Toxicity Tests are no longer administered since time of appearance of signs and symptoms at a given pressure can vary - in one individual - from a few minutes to longer than an hour over a period of several days.

Dr Deco :doctor:

 

[MSilvia]

Msilva -No i am not diving 2.0 and no I do not recommend 2.0, I only brought it up to say that 1.18 is a long way from 2.0.

Glad to hear it.