Catalina Diver died today w/ Instructor

[ScubaSam]

There's another lesson here. It may or may not have been applicable in the Catalina accident, but it's a good general lesson for all of us.

It sounds like what you were doing was shallow hyperventilation, sort of like panting. When someone starts to get nervous (even if they don't realize it) or maybe starts working harder than planned, it can be a common breathing pattern.

The problem with shallow hyperventilation is that you are now not exhaling fully. So what's happening is that the CO2 your body is producing, which would normally have been expelled when you exhale, is slowly building up.

As you were (hopefully) taught in your basic class physics discussion, CO2 is the stimulus to breathe. The more CO2 we have, the more urgent that need feels like.

When you shallow hyperventilate and the CO2 builds up, you start to feel like you can't catch your breath. You may take a breath off the reg and it doesn't satisfy the feeling of air starvation. But it has nothing to do with you not getting enough air IN. It has to do with you not getting enough CO2 OUT.

So if you find yourself in this situation, the thing to do is . . . EXHALE. As big as your can. Take a breath. Exhale BIG again. Take a breath. Exhale BIG again. Generally two, three, or four BIG exhales will blow off enough CO2 that the not-getting-enough-air feeling will go away.

And once you get rid of that need-more-air feeling, you can decide whether or not to continue the dive. To me, this is all part of the walk-away lesson from your experience. Thanks for sharing.

- Ken

Ken - Sounds similar to what happened to me the first time I was 85 ft. I started experiencing tunnel vision and felt my reg was not giving me enough air. I looked at the other divers around me to see if they looked the same as how I felt, they did not. I looked at my SPG which told me I had more than enough air so I took deep inhales and exhales until the tunnel vision went away. I felt comfortable enough to continue the dive after the tunnel vision went away. My first and last time I ever had that experience.

 

[Bubbletrubble]

FWIW, there's research to suggest that CO2 retention exacerbates the effects of narcosis. At the very least, it is likely coincident with inadequate oxygenation of...the brain. Ken's recommended technique to slowly inhale and exhale fully can effectively head off these problems before they become a real issue. This is definitely something that should be taught to students before the deep dive of the AOW specialty.

 

[Teamcasa]

New thread:
http://www.scubaboard.com/forums/ba...0623-co2-buildup-cause-effects-solutions.html

 

[PCH Scuba - Brett]

Thanks for the comments of all. I had a dangerous situation occur yesterday on dive #4 of a deep specialty dive. All ended well, but certainly my mind went to the instructor not as fortunate yesterday.

While I will not identify the instructor nor the dive shop she is associated with, I would like to say she is an outstanding, deliberate instructor. The dive shop she is associated with is also top notch.

 

[drbill]

The instructor contacted me to clarify the issue of the OOA signal and the timing of the student bolting. The student did not signal she was OOA until she had risen from depth to 25 ft. During this period of the ascent, the instructor was trying to prevent her from ascending too fast. At the shallower level, the student gave the OOA signal and immediately bolted. My understanding based on what the instructor told me is that she bolted too quickly to accept another air source. The instructor believes she may have already suffered trauma during the initial part of the ascent due to holding her breath and that may have been what caused the student to bolt from 25 ft to the surface.

The student was still breathing shallowly when the instructor joined her at the surface and it is my understanding from rescue personnel that there was intermittent breathing and a heartbeat during part of the transport to the chamber.

Thanks, Brett, for weighing in with your comments. She is indeed a very good instructor.

 

[Leejnd]

Thanks Dr. Bill. I figured it was something like that.

Although I do think that it is a good reminder to us all that if someone gives you the OOA signal, your very FIRST action should be to immediately offer your alternate...and figure out what the problem is second.

I just had my first (and I hope only) OOA experience myself, and am happy to report that that is exactly what my buddy did - his octo was in my mouth in a millisecond, even though he was probably not sure what was going on. If he'd hesitated, I was about to ditch my weight belt, which may very well have landed on the head on one of the divers doing their safety stops below me...so I'm very glad that it was his instinct to immediately respond in that fashion. Good lesson.

 

[merxlin]

Thanks Bill for the update.

I hope that the instructor is able to get past this and continue teaching. She obviously loves what she does, and those that know her seem to have a very high regard for her.

 

[DandyDon]

Thanks Bill. I take it that the Inst is following this thread, which is not at all surprising. My best wishes to her as this is a very close & personal loss to her as well as to the loved ones of the deceased. Friends like you are a great benefit to her in this hard time I am sure as discussing the tragedy with trusted others is always helpful, so much better than not. I know this is hard on you too, and hope you all find the support you need. You got mine big guy...!

We all want to know what happened NOW, and we really can't help ourselves from dissecting the incident and tossing out our ideas of what might have happened.

That is not usually my intent altho I can't help myself at times. Usually here my speculations on what-ifs are to think thru possible problems that could have lead to the outcome and think ahead on how I might control some of those. LA County will determine how it really happened, but what I learn may well be from other possibilities as well.

Although I do think that it is a good reminder to us all that if someone gives you the OOA signal, your very FIRST action should be to immediately offer your alternate...and figure out what the problem is second.

I remember giving a buddy a dirty look once on a LOA signal but then gave him my pony reg and have since avoided that selfish reaction. Other LOA and OOA signals I've always handed first, investigated next, the safest way to go for sure. I really encourage buddies and boatmates to just grab either one of my alternates without asking tho, and I'll understand - and I chose to keep my pony valve full on during every dive, even tho many close theirs after charging. Hell, it's a lot of trouble to keep that pony & reg serviced, transport it to other countries, carry it on every dive, etc - so I sure don't mind it being used now and then. If they signal tho, I whip it out and purge to show it's open.

 

[openmindOW]

DRBILL, thank you for the information.

PCH BRETT, please consider telling us about your deep Dive experience that occurred that other day. It might be good to start a separate thread.

 

[Ayisha]

I had a situation when I was not able to get air from my reg, but my gauge was reading 1500 psi. We of course don't know why the victim believed she was out of air, but I know the feeling when you can't breathe through a reg even if there is air.

I have mild asthma but had not had an attack in over 10 years. I was supposed to take my puffer preventively before cold water diving but I had forgotten the second day of my o/w course. My new too-overhanging hood kept pushing off my mask constantly so that I was constantly replacing and/or clearing it. It got to the point when I was repeatedly exhaling to clear way more than I was inhaling - one quick breath in, exhale, repeat - and was exacerbated by exposure to dog hair earlier, which is a major allergen for me. I was breathing fine and then it quickly degenerated within minutes. This caused me to hyperventilate and have an asthma attack at about 20 feet waiting for my turn to do skills. I had 1500 psi in my tank but could get almost no air due to my lungs almost shutting down. The instructor tried to find the problem with my mask/hood but could not help me fix it. I could only breathe slightly when I signalled OOA and thumbs up to my instructor. He looked at my gauge and shook his head. I gave the thumb a couple more times and he shook his head each time. I could no longer breathe at all. Finally I signalled out of air again, gave the thumb and decided I was going up with or without him. The DM grabbed me and made sure I was going very slow and I exhaled for all I was worth. For the first time I was aware of my lungs and felt them expand extremely painfully in my chest and I thought I was going to over-expand a lung. I exhaled as much as I could, though it was like nothing, just a tiny puff. The surface brought no relief, even without the reg. I was having a full blown asthma attack brought on by repeated mask clearing and exposure to an allergen.

I was signalling OOA because I could not breathe, not that there was no air in the tank.

It may seem unfathomable that someone could be unable to draw air or enough air from a working reg or a tank with air, in addition to retaining excessive CO2. Some of the reasons it can happen are if someone hyperventilates, overbreathes their reg, is working too hard, has a reg that has a higher work of breathing or has an asthma attack underwater.