Very scary moment at depth - what happened?

[Codiak]

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

Only reason for mentioning it is that 32% is banked where I live and 28% is a "custom" blend.
Custom blending "suggests to me" over thinking things a bit and perhaps per dive stress.

That's not to say there's anything wrong with the mix itself.

 

[ianr33]

CO will not affect your breathing rate. It will give you a BAD headache.

I doubt CO is an issue here, as your headache cleared a few minutes after surfacing.

 

[danvolker]

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.

You may be right...but many new divers will "skip breathe" and not know it is skip breathing...for that matter, a HUGE number of "old timers" that mostly do shallow dives, will skip breath also....goig deep just has to change this.

 

[Marty!]

You may be right...but many new divers will "skip breathe" and not know it is skip breathing...for that matter, a HUGE number of "old timers" that mostly do shallow dives, will skip breath also....goig deep just has to change this.

Can you elaborate? I'm not familiar with skip breathing. (or maybe I am but haven't heard the term)

 

[markmantei]

CO will not affect your breathing rate. It will give you a BAD headache.

I doubt CO is an issue here, as your headache cleared a few minutes after surfacing.

Not saying CO is a slam dunk, but, a quick google search to confirm symptomology...
From Scuba Diver Info - Diving physiology "headaches, confusion, tunnel vision and worse".

Sounds pretty much like what the OP described.

While I don't know how long the headache would last (help me out here ), first aid treatment is oxygen, which the OP indicated he recieved, which, if it was CO, would certainly limit the duration of the symptoms.

 

[markmantei]

Can you elaborate? I'm not familiar with skip breathing. (or maybe I am but haven't heard the term)

From wikipedia, which says it more eloquently than I...

"Skip breathing is a controversial technique to conserve breathing gas when using open-circuit scuba, which consists of briefly holding one's breath between inhalation and exhalation (i.e., "skipping" a breath). It leads to CO2 not being exhaled efficiently. There is also an increased risk of burst lung from holding the breath while ascending."

 

[melanie.]

Hi Marty

Speaking from experience, I doubt you are going to find one true reason about what happened wrong on your dive. From what you mentioned, it really doesn't seem like there was any one thing different that could have set you off (baring any technical problems that you are so far unaware of). It could be that it was just a certain combination of elements that made for a bad experience. The way I see it is that some times the water likes to remind us who is boss, and throw us for a loop.

But everyone has included great points. It will make you think next time.. am I close enough to my buddy, is my thermal protection adequate, how is my breathing, what is my mental state like going into the water, do I really feel like being this deep etc etc. Just remember that you did learn from this dive, that you could prevent full blown panic and make a relatively safe ascent.

Take your time, think it over, and best of luck on your next dive!

 

[Crush]

H.. am I close enough to my buddy, is my thermal protection adequate, how is my breathing, what is my mental state like going into the water, do I really feel like being this deep etc etc.

Those are all excellent points, especially being close to your buddy. My heart rate may increase when I encounter a problem, but sometimes (i.e., if I can't resolve the problem myself) it increases again if my buddy is 10 feet away and headed away from me...

 

[ianr33]

While I don't know how long the headache would last (help me out here ), first aid treatment is oxygen, which the OP indicated he recieved, which, if it was CO, would certainly limit the duration of the symptoms.

Interesting thread here http://www.scubaboard.com/forums/no...f/369493-carbon-monoxide-poisoning-scary.html

Apparently the half life of carboxyhemoglobin (CO bound to hemoglobin) is about 300 minutes; on 100% oxygen therapy, it is about 60 minutes, so even breathing pure O2 a Carbon Monoxide headache would seem unlikely to go away in a few minutes.

Mu understanding (and I am certainly no expert) is that an acute CO incident as might occur with contaminated gas is going to lay you out for several hours at least.

 

[SeaHorse81]

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.

During my surface intervals, I work with people with anxiety, depression, etc. While I began reading this thread with the expectation of seeing something strictly scuba-related, I quickly recognized OP's description as being what sounds to me like a panic attack (a severe spike in anxiety, commonly experienced by millions of people in a variety of circumstances), which happened to occur underwater. As quoted above, I suspect residual stress from the day before contributed greatly, and it's possible that the anticipated challenges of the new day's dive were just more than your system was ready to handle.

Panic attacks are not the same as the panic we talk about in diving. A panic attack is experienced most often as an urgent sense of foreboding and need to escape, commonly followed by a well-controlled exit from the place in which the panic attack is occurring. People having panic attacks in crowded rooms don't generally run screaming from the room, for example, they just exit as efficiently as possible, horribly distressed in the process, but showing little outward sign of their suffering to others.

I don't know that OP's experience was nothing more than a reaction to too much stress in too short a time, but am offering that as another possibility to consider in sorting it out.