Am I too afraid of lung barotrauma? Remedies/Techniques?

[dmaziuk]

I always think that I need to give it a little extra "push". Better "safe" than sorry kinda.
Other divers report the sensation of feeling how the one breath they took before ascending just never seemed to end as they ascend. I dont remember feeling that. I just felt the " getting close to having to breath again" sensation.

My concern would be that during a deep CESA or other exercise I would exhale too much and run out of air during the ascent, fail the exercise or inhale during the ascent getting myself hurt.

Do not exhale, just keep your airway open. It takes practice. You can practice it in a lap pool if you can get into one, front crawl works well as it puts your head at the same angle you'll have looking up during ascent.
Couple of things to note:
- good news is that under normal circumstances you have about a minute's worth of O2 in your lungs, blood, and tissue, to keep you going. There should be more when coming up from a dive at higher PPO2.
- The bad news is that your urge to breathe is not controlled by oxygen, it's triggered by CO2 build-up. You will not be venting enough CO2 during CESA and a long one will get very uncomfortable. Controlling the urge to breathe is part of the practice, check freediving sites for various techniques.
- Last but not least I strongly doubt I personally could do CESA slowly enough, so my concern would be excessive bubbles from blowing the safe ascent rate.

 

[tmassey]

Last but not least I strongly doubt I personally could do CESA slowly enough, so my concern would be excessive bubbles from blowing the safe ascent rate.

That’s my fear as well.

A minute is a very low minimum to be able to keep conscious. But I always assume that the scenario goes something like:

- I breathe in. I continue with my dive like nothing is wrong.

- I exhale.

- I inhale. The reg locks immediately. Uh oh: “no” air in my lungs and no more is coming.

At this point I’ve got hard choices: find my buddy or CESA. If I’m a smart, responsible and careful buddy, he’s right there. Boring story. If I’m an absolutely lousy buddy, he’s too far and you make the CESA immediately. But worst case, he’s close enough to try.... but swimming away, not paying attention, etc. and I waste 15-20 seconds *and* O2 in my tissues trying.

- Now I try the CESA, from 130’. (Of *course* it’s 130’. I said it was my fear, didn’t I?) Now I’ve got, what? 30 seconds? I’d hate to black out at 20’...

Plus no air in my lungs, plus CO2 buildup, and the great tank in the sky is 130’ (2+ minutes!) and 4ATA away...

Root Cause Analysis says the fault is not the CESA, it’s the several mistakes I already made. But if I’m at the bottom of that particular incident pit, it will be awfully tough to stay slower than my large bubbles on the way up...

Threads like this make me want to practice this. Facts like CESA being by far the most dangerous aspect of Open Water training cause me not to. I don’t really consider it an option in my current arsenal.

I kind of put it at “jumping from a burning building” level self-rescue: only if highly-likely death is the alternative...

Which puts it back to the original topic for the original poster: take CESA and lock it away. The solution is not to get comfortable with CESA. The solution is to ensure that you always have an alternative to CESA. (My preference: redundant air source FTW!)

ETA: for dives not deeper than, say, 60’ or so. I think CESA is not near-suicide then. Likely much lower tissue loading and much shorter time. But at 90+ feet, it’s a tough sell to be a reliable technique. Which is why deep diving needs more respect and resources.

Of course, as they say, you can fix bent. You can’t fix dead. So if it’s drown or blow, blow it is. But don’t kid yourself: you won Russian Roulette.

 

[BlueTrin]

That’s my fear as well.

A minute is a very low minimum to be able to keep conscious. But I always assume that the scenario goes something like:

- I breathe in. I continue with my dive like nothing is wrong.

- I exhale.

- I inhale. The reg locks immediately. Uh oh: “no” air in my lungs and no more is coming.

At this point I’ve got hard choices: find my buddy or CESA. If I’m a smart, responsible and careful buddy, he’s right there. Boring story. If I’m an absolutely lousy buddy, he’s too far and you make the CESA immediately. But worst case, he’s close enough to try.... but swimming away, not paying attention, etc. and I waste 15-20 seconds *and* O2 in my tissues trying.

- Now I try the CESA, from 130’. (Of *course* it’s 130’. I said it was my fear, didn’t I?) Now I’ve got, what? 30 seconds? I’d hate to black out at 20’...

Plus no air in my lungs, plus CO2 buildup, and the great tank in the sky is 130’ (2+ minutes!) and 4ATA away...

Root Cause Analysis says the fault is not the CESA, it’s the several mistakes I already made. But if I’m at the bottom of that particular incident pit, it will be awfully tough to stay slower than my large bubbles on the way up...

Threads like this make me want to practice this. Facts like CESA being by far the most dangerous aspect of Open Water training cause me not to. I don’t really consider it an option in my current arsenal.

I kind of put it at “jumping from a burning building” level self-rescue: only if highly-likely death is the alternative...

Which puts it back to the original topic for the original poster: take CESA and lock it away. The solution is not to get comfortable with CESA. The solution is to ensure that you always have an alternative to CESA. (My preference: redundant air source FTW!)

ETA: for dives not deeper than, say, 60’ or so. I think CESA is not near-suicide then. Likely much lower tissue loading and much shorter time. But at 90+ feet, it’s a tough sell to be a reliable technique. Which is why deep diving needs more respect and resources.

Of course, as they say, you can fix bent. You can’t fix dead. So if it’s drown or blow, blow it is. But don’t kid yourself: you won Russian Roulette.

If that’s your worry: 130 feet and OOA, you may just want to get a redundant source of air (twin-set, pony, ... etc)

 

[dmaziuk]

- Now I try the CESA, from 130’. (Of *course* it’s 130’. I said it was my fear, didn’t I?) Now I’ve got, what? 30 seconds? I’d hate to black out at 20’...

At 130' it should be more than 30 seconds due to higher PPO2. And you shouldn't black out, for the same reason. But keeping your urge to breathe in check is gonna really suck.

In other news the surface is much much farther than it looks from below, and the other side of a swim-through is nowhere near as close as it looked from the entrance.

 

[boulderjohn]

- I breathe in. I continue with my dive like nothing is wrong.

- I exhale.

- I inhale. The reg locks immediately. Uh oh: “no” air in my lungs and no more is coming.

Nope. Here is what would happen at 130 feet.
You inhale and notice that it seemed a little harder to breathe then normal. When it is even harder to breathe on your next inhalation, you look at your SPG and think, "OMG! I'm OOA!" You look around for a buddy as you inhale again and decide you have to do a CESA, and you do it with a full breath of air.

Plus no air in my lungs, plus CO2 buildup, and the great tank in the sky is 130’ (2+ minutes!) and 4ATA away...

Because of the fact that your last breaths were getting harder to inhale, you had enough warning to start with full lungs, but even if it did happen suddenly, your lungs would be at least half full, probably more. We do not empty our lungs when we exhale--not even close. Try this. Pay attention to your normal breathing right now as you are reading. After your next exhalation, at the point you are about to inhale again, keep exhaling, forcing yourself to empty your lungs to the greatest degree possible. You will be amazed at how long it will take you.

When you start to exhale on ascent during a CESA, it will be a minimal exhalation for a while, because your lungs are not full, but as you ascend, they will fill because of the expanding air. If you started with a full breath, the air will start coming out rapidly pretty much right away. If you started with no warning and only half-full lungs at 130 feet, your lungs would not be full until you are well past half way up, depending upon how fast you exhale. As you continue to ascend, the air will begin to escape faster than before, and it will really be coming out fast in the last part of the ascent.

The reason it got hard to breathe just before you went OOA was because the ambient pressure (5 ATA) at 130 feet was too much for your regulator to work against. When you get shallower, it will be able to give you a breath or two.

EDIT: When I wrote this, I had not seen the US Navy training film on emergency films that I linked in the next post, and I did not realize that the Navy tells (at least then) divers not to ascend with a full breath but rather to exhale before beginning the ascent.

 

[boulderjohn]

BTW, at 130 feet, PADI recommends you do a buoyant ascent rather than a CESA. There is almost no difference--in a buoyant ascent, you inflate the BCD and/or drop weights so your ascent is rapid rather than controlled. Everything else is the same.

Here is a 1958 US NAvy training film showing the procedure of using a buoyant ascent to escape from a submarine at depth. Notice how the air comes out. Notice, too, that the film makes two points that will interest most people:

• The navy divers are instructed to exhale before starting the ascent so that they lungs are not full.
• They say that these ascents have been done without a problem from 300 feet.

 

[tursiops]

awfully tough to stay slower than my large bubbles on the way up

It is a myth that this is a useful ascent rate indicator. But, Hey! It's your story!

 

[rongoodman]

As others have mentioned, it's not likely something you are likely to run into in advanced training. I am certified in cave, trimix, and rebreather diving and have never heard it mentioned beyond my initial OW course.

 

[tmassey]

It is a myth that this is a useful ascent rate indicator. But, Hey! It's your story!

Finally someone who got it. (At least, sarcastically........)

It *is* a story. It’s a fear. Like most fears, it’s built on a tiny bit of reality, but blown out of proportion.

Does anyone not see my profile photo? Or my profile education listing? I think I might know a thing or two about how to solve this problem.

That’s the point. Fear is like that. Sometimes you deal with it with facts, experience and training. And sometimes you just have to set it aside.

But thanks to all you SB know-it-all’s for correcting me. I won’t bother to correct the further inaccuracies in the supposed “mistakes” or “solutions” to my fear. Because the point was, fear over a “solution” that isn’t a solution, to a problem caused by a half-dozen compounding mistakes is not going to be fixed by technicalities. It’s emotional. And has to be addressed as such.

 

[TMHeimer]

Nope. Here is what would happen it 130 feet.
You inhale and notice that it seemed a little harder to breathe then normal. When it is even harder to breathe on your next inhalation, you look at your SPG and think, "OMG! I'm OOA!" You look around for a buddy as you inhale again and decide you have to do a CESA, and you do it with a full breath of air.

Because of the fact that your last breaths were getting harder to inhale, you had enough warning to start with full lungs, but even if it did happen suddenly, your lungs would be at least half full, probably more. We do not empty our lungs when we exhale--not even close. Try this. Pay attention to your normal breathing right now as you are reading. After your next exhalation, at the point you are about to inhale again, keep exhaling, forcing yourself to empty your lungs to the greatest degree possible. You will be amazed at how long it will take you.

When you start to exhale on ascent during a CESA, it will be a minimal exhalation for a while, because your lungs are not full, but as you ascend, they will fill because of the expanding air. If you started with a full breath, the air will start coming out rapidly pretty much right away. If you started with no warning and only half-full lungs at 130 feet, your lungs would not be full until you are well past half way up, depending upon how fast you exhale. As you continue to ascend, the air will begin to escape faster than before, and it will really be coming out fast in the last part of the ascent.

The reason it got hard to breathe just before you went OOA was because the ambient pressure (5 ATA) at 130 feet was too much for your regulator to work against. When you get shallower, it will be able to give you a breath or two.

EDIT: When I wrote this, I had not seen the US Navy training film on emergency films that I linked in the next post, and I did not realize that the Navy tells (at least then) divers not to ascend with a full breath but rather to exhale before beginning the ascent.

Think I follow all that. I practice my CESA from 30' starting with lungs about half full. I figure if I am able to grab a full breath from my tank, then I probably could start up doing a normal ascent. Is this sound reasoning?