Lung oedema in a pool

[Chefkoch]

Yep folks, it seems that you can experience a lung oedema in a pool, here's my little story:

I had a very tiny lung oedema after a negative pressure pool session.

We have a nice training pool, 21*22*5m, and recently I've started to seriously train negative pressure dives.
I passively let the air out of my lungs, without forceful exhalation, slowly dive to the bottom, and then dive the lane at that depth.
Dive is usually followed by a 30sec surface pause, then I dive the next lane. Alternatively i do a 1min surface pause, followed by a 15-35sec pause at the bottom, then dive the lane.

Equalistion is fine, lung squeeze is mild, but definately more than what i experienced @ -45m in the sea.

Last week ago i did this regime wearing my stereos, everything was OK.
This week i had my mono on, and - of course - when finning with it with a squeezed lung - every time i contracted my abdominal muscle lung squeeze was noticeably increased, and again increased by diaphragmatic contractions (which happen quite early)
At the same time i was feeling extremely relaxed, heart rate went down as expected, and i was in a constant dreamy, yet focused, relaxed state.

After 18 dives i came up with an urge to caugh (like something tickling your lung, like you had some water in it). Usually i would feel this urge after one empty-lung dive to that depth (lung totally empty), then I would start with a few superficial breaths, slowly increasing the lung volume, and it would go away in a matter of seconds.

That's exactly what i did this time, but it didn't go away, and after coughing for a min or so, i expectorated some brown-reddish stuff, looking exactly like blood serum. Ok, so a little oedema, meaning i overstressed my lung capillaries, and a few have burst open, letting blood pass into the underpressurized lung lumen.

So, here are my conclusions from this:

1. Be careful with negative pressure dives, you can obviously hurt your lung at shallow depths already.

2. Special care must be taken when using a monofin: the contraction of your abdominal muscle will further increase the negative pressure in your lung.

3. Repetitive negative-pressure dives represent a great deal of stress for your lung: I feel my lung is more squeezed on a -5m neutral-lung dive, compared to a -45m full lung dive. I think it rather mimicks a -60m dive. On a true -60m dive, negative pressure will gradually build up, allowing a gradual blood-shift to compensate the underpressure. Now imagine going to -60m in just 5seconds, and very often in a row, that is a lot of stress.

4. Blood shift: i feel it already happens in the pool on a neutral lung. First off, when i close my eyes and let go i feel exactly like being down at depth. I mean this strange, dreamy state that only comes with depth. Second thing: i get a bit of lactic acid in my thighs after diving only 1 lane on a negative lung. This would not happen even after 3-4lanes on a full lung! I see the reason in bloodshift, and profoundly manifested diving reflex, which will greatly restrict peripheral blood flow, leaving your legs without oxygen.


Has anyone else experienced similar stuff?
Do you guys also feel the blood shift, or am i just fantasising?
What are your negative-pressure routines in the pool or open water?
Has negative-pressure training improved your deep hangs/deep statics/deep chillout/deep aspetto time? Cause that's the main reason i do it: to simulate depth and lung squeeze, and get used to the feeling of having your lung squeezed, and overcoming the urge to breathe usually triggered by a compressed lung.

I'm curious, so post on!:friday :wave :blackeye

 

[jome]

I think your observations are spot on.

Great way to accomondate to pressure, but you have to be extra careful. As you stated, you reach a lung volume equal to -60m in a matter of seconds, instead of gradully dropping there.

I've had some wheezing in my breath after a particularly hard empty lung training, especially after a long break. You have to gradually build up to it and not do 18 dives per session

 

[DeepThought]

Do you guys also feel the blood shift, or am i just fantasising?

I usually feel it too.

What are your negative-pressure routines in the pool or open water?

FRC - much less risk of lung squeezes.

 

[naiad]

It is certainly possible to get a lung squeeze in a pool. A dive buddy said that he has known it to happen during pool training with empty lungs. More about pool training and lung squeeze on [ame="http://forums.deeperblue.net/showthread.php?t=57421"]this[/ame] thread.

I have tried it, but it hurts even at 3m, and I am scared of accidentally breathing in water, so I don't do any exhale diving myself.

If you are going to do negative pressure dives, it is very important to build up gradually.

Lucia

 

[Chefkoch]

Ohhhhhhhhh, i have a big problem there: I'm hooked!:duh It gives me this feeling of being deep, and i miss it a lot.

I did it again yesterday, but very carefully, and only on 4 dives. Was using stereo fins, and i got good lactic acid in my thighs. The bloodshift definately makes the difference for me: i lie down on the pool floor and feel how i shut down, or - to use the words from the big blue - slipping without falling. Whooooohooooooo!

 

[dannybuoy]

Yeah, that is an incredible feeling, isn't it?

Where i train there's a 5 meter deep pool as well, and fortunately there was someone who got educated about these excercises. He taught me to really respect these full exhale dives, to treat them as a dive to 50 meters deep. That means descending in 45-60 seconds, and ascending just as slowly. We use a rope with weights at the bottom to do it, and i began by exhaling at 3 meters deep. Then 2, then 1, then i stopped for the day, for man, my ribcage felt like it had been run over by a truck. Water's a powerfull thing. Took me a couple of sessions before i could do a full exhale above water, but oh the joy. Got back up after a 2 minute dive, buddy measured 8 heartbeats in 15 seconds at the bottom, and i thought i was experiencing a samba, but without the shakes. Looked at my hands thinking "What the fornication is going on?" for they weren't shaking, but i had the strangest good feeling. Turned out it was my blood coming back to my limbs. Who knew? Scary thing is, like you described, getting contractions. So i make sure i'm rested enough to do the excercise, and if i'm tired i stay away from anything empty lunged. Contractions on empty lungs is just too scary for me. Perhaps you can skip the swimming part and just lay there at 5 meters?

Oh, and if you feel like doing something fun, perhaps you haven't done this yet: i call it the parachute, and what you do is you lay on the surface, you passively exhale (FRC), and when you start to sink you arch your back and hold out your arms as though you were jumping from a plane. That way, you fall but you also fly forwards. Backwards is fun too but it's a bit of a bump at 5 meters. There's a mild squeeze but nothing like a full exhale, so you don't need to worry about coughing up blood or horor movie stuff like that.

Oh, and Lucia, i thought it's almost impossible to inhale fluids, since humans have an automated respons to shut the airways whenever fluids get in your mouth; am i wrong about that? In any case, if you have a buddy, i'd definitely try it. Scary, but definitely interesting.

 

[naiad]

It is something I want to try, but only after gaining a lot more experience, and when I am feeling better than I am now. It sounds like a very good idea to descend slowly, because this is much more similar to a deep dive than just exhaling forcefully and sinking like a stone.

Oh, and Lucia, i thought it's almost impossible to inhale fluids, since humans have an automated respons to shut the airways whenever fluids get in your mouth; am i wrong about that? In any case, if you have a buddy, i'd definitely try it. Scary, but definitely interesting.

I am not so worried about inhaling fluids underwater, because even if it feels like I might do it, I'm sure I won't. What I am more worried about is surfacing and accidentally breathing in water that is in my mouth or nose. This is what makes it different from deep diving, because although the pressure at depth reduces lung volume, it expands again during the ascent. With empty lung diving, I arrive at the surface with empty lungs.

 

[fpernett]

As many of you said it, exhale diving is a serious thing.

I have been doing it for the last year, and I recommend an slow approach. It`s better to start in a shallow pool (2 meters) and stick to FRC until you feel comfortable. In FRC, there is least possibility of a pulmonary oedema, because the pulmonary resistance is lower.
Once you feel comfortable with this, then try Exhale dives. Reverse packing exhales dives are more dangerous, and should be practised after many exhale and much more FRC dives.
Because the risk of BO on a full exhale dive, always use a buddy. And don't take to long down. It`s not the purpose of this exercise.

At this moment I'm doing Reverse Packing Exhale dives in a 5 meters pool, and I felt the pressure much more than my deepest dive in the sea.