Very scary moment at depth - what happened?

[Crush]

If you describe panic as a "get me the heck out of here" trashing race to the surface, I have never panicked. I have, however, felt my stress levels climbing towards panic. As you know, the key is to sort out the small stressors before the stress becomes panic.

For me, stress is rarely caused by one thing. It is usually a mix. For example, cold, dark, depth, salt water leaking into mask stinging eyes, narc, etc., etc..

 

[danvolker]

True..skip breathing can be a habit for divers doing 60 foot or less most of the time, that they get a way with....suddenly they do a dive to 120, and the skip breathing is VERY BAD for the dive, and there is no getting away with it. This would actually appear the simplest/most likely issue leading to the dark narc.

 

[Hallmac]

Just another thought: You might also want to think about getting your air analyzed for CO2.

I second this thought for a few reasons. First you stated you were using 28%, if it was partial blended in a hurry the chance of a fire increases trapping CO inside the cylinder. Second, while not always the case, Narcosis generally lifts as you decrease the pressure. If your ascent was controlled, and the feeling was still present at the shallower depths you either spooked yourself or it was caused by something other than narcosis.

 

[ianr33]

and not having enough O2 will get the panic cycle started.

Could you explain that please?

 

[Codiak]

A lot of good comments so far.

cold, dark and a bit of buddy separation perhaps? ( you went to 120, did your buddy as well? )

I'm not claustrophobic, but can get that feeling when narced.
Slow, deep breaths and constant accent rate normally clear it for me.

I'd have used 32% for those depths for greater bottom time as well.

Still it sounds like a mild panic attack setoff my narc, I say mild as you still had the presence of mind to check your gauges and control your ascent rate.

Btw, it's quite possible you hadnt worked out all the nagging mental issues from the previously rough dive. Take a week, shakeout the cobwebs and go do some less stressful dives.

 

[ianr33]

I'd have used 32% for those depths for greater bottom time as well.

That would put pO2 above 1.4. IMHO the 28% that was used is a perfectly good choice.

 

[danvolker]

That would put pO2 above 1.4. IMHO the 28% that was used is a perfectly good choice.

Absolutely...! Higher O2 is NOT going to reduce Narc at all...only lead to higher toxicity, and much more free radical formation ( you know, the stuff you take Vitamin C and E for, because you know how damagingh they are to your body )

As one poster intimated, you will not have any sense of too low an O2 level. You will get a sense of too high a Co2 level though.

If I bring my wife Sandra down on a wreck or reef that is 130 or 140 feet deep, I am going to have normoxic trimix in her tank....This is 21 % O2 ( what air has in it), and 35 % helium--enough to drastically reduce the narc of nitrogen at 140 feet.
Ascent and stop at 20-10 feet , is like a slow nitrox ascent, better with a deep stop --for you around 60 in your profile. Helium is much healthier for your body than high nitrogen at depth, and much better for you than high O 2 mixtures as well.

My comment about what I would do with Sandra, is about thinking about the real dangers or challenges in a dive, and minimizing them. Nitrox will NOT do this at all. IT will lessen the DCS concern somewhat, if you stick to air tables....but it will not help you with the narcossis issue, which may well be by far the greatest threat you face on such a dive.

 

[merxlin]

Originally Posted by merxlin

and not having enough O2 will get the panic cycle started.

Could you explain that please?

Yes, I neglected to see he was diving Nitrox and assuming it was analyzed at the level he stated- the O2 level should not have been in question. CO2 could still be an issue though. I edited my post.

 

[Marty!]

A lot of good comments so far.

cold, dark and a bit of buddy separation perhaps? ( you went to 120, did your buddy as well? )

I'm not claustrophobic, but can get that feeling when narced.
Slow, deep breaths and constant accent rate normally clear it for me.

I'd have used 32% for those depths for greater bottom time as well.

Still it sounds like a mild panic attack setoff my narc, I say mild as you still had the presence of mind to check your gauges and control your ascent rate.

Btw, it's quite possible you hadnt worked out all the nagging mental issues from the previously rough dive. Take a week, shakeout the cobwebs and go do some less stressful dives.

With regards to the mental issues you mention, it's true that I was thinking about the previous dive I made and felt the narcosis hitting hard - could have been a contributor I suppose.

As far as the buddy separation, yes there was some, and that certainly is a lesson learned from us. Had we kept closer together always at the same depth I could have much signaled her much easier.

 

[Marty!]

My thoughts as well, except not CO2, but CO. I'm no doctor, but I believe your symptoms could have been caused by carbon monoxide, even a small amount can cause issues as partial pressure increases your exposure at depth. There are a few threads you can find on CO analyzers (I use the analox EIICO). Also possibly CO2 retention? How was your breathing? A few deep breaths should start to rectify CO2 retenion due to skip or shallow breathing.

As far as I can remember my breathing was fine before the panic started - after that I imagine it quickened. My gas consumption didn't seem crazy off the mark, as all things considered I used about 1700psi of a 100 cu.ft tank.

I'll try and follow up with the shop and mention about any CO present in their nitrox mixes.