Little River - Out of Breath

[IRAP Administrator]

The plan was to swim to the Florida Room via the Merry-Go-Round tunnel (right at the T), then check out the large cracks in the ceiling of the Florida Room. My buddy took the lead. From the start his pace was brisk. At some point I remember thinking how I wouldn't be mad if he slowed down a bit. We hit the second T at the start of the Florida room any my buddy turned to me and gave a two-handed "NO MORE" sort of a signal, followed by double thumbs up. I gave him an "OK" and returned the thumbs up, gestured for him to lead out. After 200 feet or so, he seemed to calm down. His pace slowed and his movements relaxed. The rest of the dive took a bit of a recreational feel, with him peeking under beading planes other such non-panic behavior.

Discussion at the surface revealed he started losing control of his breathing rate 1/2 way down the Merry-Go-Round tunnel, and by the start of the Florida room he was starting to panic. Upon exit and reaching the first T the panic had subsided, and his breathing rate was back under control.

Other bits of information:
1) buddy does multiple cave dives a week, and has for over a year
2) buddy is a physical laborer, and skinny by my standards
3) buddy is a heavy smoker
4) flow in Little River was very low
5) buddy used all fining, and no pull and glide
6) no CO testing was done on any of the tanks pre or post dive (cylinders were O2 tested, and fell somewhere in between air and 32%)
7) most of the dive was at a depth of 90'

What all contributed to this incident? Is it simply insufficient o2 in the blood? Or possible CO2 or CO related? The obvious answer seems to be "he was a heavy smoker and over exerted"... but why (physiologically)? Do depth and flow have much to do with it?

[AB8CD]

I have used other's regulators and at depth found that they breath harder than I prefer... It is amazing how our minds respond to less O2 than our bodies are calling for... One part of our brain is analyzing the problem and telling ourselves to slow down and calm down... While a more primitive part of our mind says, "Get the he## out of here!"

Sent from my DROIDX using Tapatalk

[Kelly Jessop]

What all contributed to this incident? Is it simply insufficient o2 in the blood? Or possible CO2 ?

Too much CO2. Driven by a goal sounds like level of work went up to reach destination,and with gradual CO2 retention anxiety increased. Exit was at a relaxed pace with less work,and less CO2 generated. In basic open water they teach you went fighting a strong current,to find a place on the bottom or something to hold onto,and just relax and breathe.

[DA Aquamaster]

I agree with Kelly that CO2 is a possible cause. The urge to breathe is not created by low O2 levels, but rather by high CO2 levels in the lungs. If a diver starts skip breathing or artificially lowering their respiration rate to conserve gas while exerting himself, they will start to retain CO2and as the levels rise in the lungs, the urge to breathe increases, along with anxiety and narcosis. In the extreme, if you combine the artificially low breathing pattern with very shallow breathing (which then never purges the CO2 out of the lower lobes of the lungs) to further conserve gas, it can produce an out of breath feeling as you never lose the urge to breath. The end result can be very rapid but shallow breathing in what feels like a very out of control situation.

It can be aggravated by a poor performing reg, or by a partially closed tank valve, as the diver never quite feels like they are getting enough air with the resulting quick but still shallow inhalations.

As Kelly suggests, just stopping and taking a few very deliberate deep breathes can begin to stop the cycle. The anxiety and narcosis however are more related to CO2 levels in the blood and that will take longer to return to normal.

CO is more subtle as if the respiration rates are normal, the CO2 levels are normal and the diver feels no particular urgency to breathe, although the lack of O2 can make you feel short of breath. But the more CO that is inspired the more CO will bind with hemoglobin (and it forms a very strong bond that then prevents O2 from binding with the hemoglobon) and the less O2 will be taken in and transported by the circulatory system. If you miss the visual symptoms, dizzyness and confusion that comes with it, eventually the lights just go out when the amount of O2 being taken in is not adequate to keep you conscious. And since the CO is stongly bound to the hemoglobin resucitation is very difficult/unlikely.

[thmoose51]

It seems to me that we are not neccessarily the same person on Tuesday that we were on Monday. A lot of different things go into how we perform(?) on a given day. Name a variable and it may apply. Amount of rest, anxiety, being goal oriented as mentioned above, whatever you can think of may effect how someone performs on a given day. He may be thin and in good shape but anxiety trumps conditioning every time so being skinny and being a hard worker may not automatically mean that he will have a great rmv under water. Maybe next time you should lead and swim at a more leisurely pace and see how he does. On the other hand, it could be you that is not at the top of his game next time you dive. He dives a lot but where does he dive? Little River can be a little intimidating for someone not used to diving in that type of system. I would say chill a bit and not worry so much about his performance on that particular day. Go with him again as soon as you can and just enjoy. As long as he is a safe diver it is all good.

[JamesK]

I would love to what type of role diet and hydration play in something like this. I know both are crucial, but to me it would be interesting to find out what a persons diet consists of. I consider myself some what of a health nut who follows what the nutritionist tells me to do, and keeps a very active lifestyle running approx 20 miles a week and biking an additional 20 along with my diving. I do cheat on the nutrition occasioanally and generally feel like I perform poorly when I do. So seeing a persons food and beverage intake in the day or two leading up an event would be something I would find fascinating.

[TJDiver]

I've been to those depths many times. However, on one dive in Little River, I was task loading and took a nark hit at just over 90 ffw just after turning the dive on time...and, this on 32%. I was to be last out, but became confused due to the narc hit, and just blasted by my team mates. One of them stopped me, got me still for a minute, and they said they could see me snap out of my narc hit like a light bulb going off. I do not recall being paniced or exiting particularly fast, but my buds said it looked like I had thrusters on my fins, and didn't know it was possible to move that fast with a frog kick. ;>) Post dive, the team debriefed, and concluded that it must have been my exertion level and CO2 contributing to my hit (Hey, I'm a bit older than them...ok, 15 years older than them). We did a second, more relaxed dive after a 3-hour SIT to the same profile, and no probs.

[T. Bix]

With all that said, it seems simply a matter of a CO hit. Trying to fin that dive back to the Florida room..... that's a lot of work and with the expectation of having enough gas to explore a little.... Maybe a nearly broken rule of goal oriented diving. I'd say good call on your buddy's part to thumb the dive when he recognized the goal to be un-reachable.

[DA Aquamaster]

CO or CO2? Unless the flow has come up recently, it's currently not much work to fin to the Florida room.

I think you identified the key element though - getting there with an expectation of having enough gas to explore, and presumably artificially lowering SAC to make that happen. That approach might work at 40-50', but at 90-100' the contribution of CO2 to narcosis makes it a non starter.

I am a big proponent of maintaining enough ventilation rate to match your exertion level and keep CO2 levels down. Rather than trying to stretch your gas and elevate CO2 levels, just bring more gas.

[FW]

I've been to those depths many times. However, on one dive in Little River, I was task loading and took a nark hit at just over 90 ffw just after turning the dive on time...and, this on 32%. I was to be last out, but became confused due to the narc hit, and just blasted by my team mates. One of them stopped me, got me still for a minute, and they said they could see me snap out of my narc hit like a light bulb going off. I do not recall being paniced or exiting particularly fast, but my buds said it looked like I had thrusters on my fins, and didn't know it was possible to move that fast with a frog kick. ;>) Post dive, the team debriefed, and concluded that it must have been my exertion level and CO2 contributing to my hit (Hey, I'm a bit older than them...ok, 15 years older than them). We did a second, more relaxed dive after a 3-hour SIT to the same profile, and no probs.

TJ may have something here. If the buddy wasn't used to diving deep, the combination of CO2 and narcosis is greater than either one by itself. When I started cavediving, I got hits like that in the current in Devil's Eye. It wasn't a problem at the entrance, just after the cave got to the neighborhood of 100'.