Lung barotrauma risk

[ystrout]

Hi everyone,

What are the risks of getting polomary barotrauma in 10 feet of water from rising 3-4 feet due to surge and slight positive buoyancy? Not holding breath but in between breaths.

Lungs around 50-70% full.

No symptoms or anything, but it's always scary when stuff like that happens.

 

[Dr Simon Mitchell]

Hello,

Very small risk.

The transmural pressures (across the lung wall) and volume changes thought required to cause pulmonary barotrauma can occur with an ascent from 1m to the surface if starting with full lungs and holding the breath. It is therefore not inconceivable (and indeed we very occasionally see it) for barotrauma to occur with short ascents in shallow water. However, such events are extremely rare despite the amount of bobbing around in shallow depths indulged in by inexperienced divers. So the risk of actual problems can only be very low in practical terms. Nevertheless it is worth trying to maintain a level of awareness of maintaining breathing discipline when using compressed gas, especially in shallow depths. There will be a small population of people with abnormal lungs who don't know it and who are at higher risk.

Simon M

 

[TMHeimer]

No medical training here, but I will say that in normal breathing, and that includes on scuba of course, there isn't a time when you close off your airway. Unless you consciously do that. Think about it -- whether breathing through the nose or mouth (or both at once), there is really no "in between" breaths since your airway never closes. The air is either going in or out. There is a minute fraction of time when it changes from in to out or vice versa, but the air is always in motion, even during the change. So, unless you consciously close off the airway to your lungs, I can't see any chance of lung overexpansion injury.

 

[ystrout]

I see.

What I meant by 'in between' is that second between inhaling and exhaling where I'm really doing anything. I also thought about another thing.

How often do you really fully inflate your lungs? I would say there's a handful of breaths every hour where I breath in all the way to satisfy that random urge. But most breaths are to about 50-70% of my lung's capacity, probably widening that safety margin.

And I dove against yesterday to 70 feet. I didn't come up unconscious or have a stroke so that's good news... Lol. I knew I didn't do anything especially since I didn't have symptoms after Saturday's dive. But I am a total hypochondriac about that kind of stuff. Haha

Thanks for the responses.

 

[dmaziuk]

I see.

What I meant by 'in between' is that second between inhaling and exhaling where I'm really doing anything. I also thought about another thing.

How often do you really fully inflate your lungs?

It's about gas expansion though: if your lungs are 70% full at 10 m and you come up to the surface without breathing, your lungs are now 140% full. If you keep your epiglottis open it doesn't matter: excess gas will just vent.

 

[ystrout]

OOOOOHHH. So when you consciously hold your breath, you clos your epiglottis?

But between breaths, your lungs can still vent?

 

[northernone]

OOOOOHHH. So when you consciously hold your breath, you clos your epiglottis?

But between breaths, your lungs can still vent?

Most conscious breath holds include tightening the powerful muscles that are used for swallowing, closing the airway. If you try it at home, you'll feel it. Pausing in breath we just aren't blowing out or sucking in and the throat/mouth isn't clamped shut. Like this air could vent normally if needed.

More importantly, as divers we are not to go up fast. The slight change in depth between breaths and the resulting air expansion should be insignificant because we aren't rocketing to the surface any way.

An emergency fast ascent (extremely rare) is sometimes called a "blow and go" and in that case, exhale while surfacing.

The replies above are excellent. Glad it's sparked further questions.
Cameron

 

[dmaziuk]

OOOOOHHH. So when you consciously hold your breath, you clos your epiglottis?

Well, you can hold your breath without closing it, it just take a little practice. I don't think people usually practice that. Anyway, my comment was more about there being two variables: how full you lungs are and how much/fast you're ascending. One doesn't tell you much without the other. The bottom line is if you don't breathe in as much as you can on every breath, and you don't bolt all the way to the surface fro depth, your risk should be very low.

 

[TMHeimer]

Well, you can hold your breath without closing it, it just take a little practice. I don't think people usually practice that. Anyway, my comment was more about there being two variables: how full you lungs are and how much/fast you're ascending. One doesn't tell you much without the other. The bottom line is if you don't breathe in as much as you can on every breath, and you don't bolt all the way to the surface fro depth, your risk should be very low.

"Holding your breath without closing it"....Interesting. To be honest, I never thought of that. I did just try it and believe I know what you mean. If you do that while ascending will your lungs inflate, or will the expanding air in lungs force it's way out your mouth since the airway isn't closed?

 

[Bob DBF]

If you do that while ascending will your lungs inflate, or will the expanding air in lungs force it's way out your mouth since the airway isn't closed?

The air in your lungs will force it's way out your mouth, the same way it will if you are breathing normally to never hold your breath.

I learned the trick when I was young, learning to swim and snorkel.


Bob