I panicked in Devils Throat at 122ft

[Rick Inman]

As soon as you begin to get winded, you let topside know you are going to "take a vent".

Good idea for OW divers to "take a vent" when needed, too.

 

[pilot fish]

You and Rick mention venting to lessen CO2 levels but I'm not sure I understand how to do that, other than stop and breathly deeply and slowly? As a commerical diver your equipment is different so to vent is probably different for a sport diver ? Would I just blow out hard through my reg to decrease CO2 levels?

Thanks for your input.

You have certainly covered a lot of ground on this thread, but I wanted to add a little something.

In commercial diving obviously the diver is physically working, often very hard. With the physical exertion comes the production of CO2. The CO2 does a lot of things. It combines with water to change the body's ph, making the entire body more acidic. It also stimulates the brain to increase respiration, and it undoubtedly does a bunch of other things that we do not even suspect as of today?

The point I am trying to make is that physical exertion, especially in the u/w environment, impacts the entire body, including the heart, lungs, brain and acid-base homeostasis.

In hardhat diving, divers constantly maintain an awareness of exertion, and overexertion. As soon as you begin to get winded, you let topside know you are going to "take a vent". A vent is simply blowing gas through the helmet free flow, to flush out any CO2, while the diver rests motionless, and topside monitors his/her progress. When you recover your breath, you return to work. Staying ahead of the wave is critical. Fall too far behind and you cannot recover.

CO2 buildup underwater is as dangerous for OC scuba divers as it is for SSA working divers. It is a significant risk that needs proper management to prevent something bad from happening??


Cheers

Cheers

 

[MXGratefulDiver]

You and Rick mention venting to lessen CO2 levels but I'm not sure I understand how to do that, other than stop and breathly deeply and slowly? As a commerical diver your equipment is different so to vent is probably different for a sport diver ? Would I just blow out hard through my reg to decrease CO2 levels?

Thanks for your input.

For the recreational diver the important thing is to first stop working hard ... relax. In most cases that means grabbing ahold of something ("establishing an anchor") and stopping whatever activity is causing you to work hard. Then slow, deep breathing to most effectively remove the CO2 from your system. This is often difficult because your brain's screaming at you to breathe harder ... which isn't really the most efficient way to reduce CO2 in a pressurized environment. Finally, calm down ... get control of your emotions, because they're working against you physiologically as well as mentally at this point. It helps to understand why you are feeling the way you do, and really concentrate on just doing what you know you need to do ... after a few breaths you'll start feeling much better, but you need to sometimes force yourself to relax and slow your breathing down against the "impulse" of what you're brain's demanding.

John's absolutely correct that the key is to stay "ahead of the curve" ... there's recognizable symptoms leading up to CO2 buildup, and as soon as you start to "feel" out of breath you need to stop ... relax ... and get your breathing under control. The sooner you accomplish that, the less dramatic the symptoms will feel.

This can be done at pretty much any depth that recreational divers are likely to go to ...

... Bob (Grateful Diver)

 

[Chernish]

You and Rick mention venting to lessen CO2 levels but I'm not sure I understand how to do that, other than stop and breathly deeply and slowly? As a commerical diver your equipment is different so to vent is probably different for a sport diver ? Would I just blow out hard through my reg to decrease CO2 levels?

Thanks for your input.

The key point is to stay motionless and to relax. Not to blow hard or anything fancy.
It's like jogging, really. You are out of breath, so you stop, take a deep breath and enjoy the scenery.

Cheers!

 

[espenskogen]

On the surface, hyperventillation you depleat the CO2 in your blood. Can cause dizzyness and fainting. That is why the recommended treatment is breathing into a bag.

Think you are wrong here.
Hyperventilation depletes the CO2 levels in your lungs. Since CO2 is what triggers the breathing reflex, it can cause you not to breathe when you need to, which reduces the o2 levels in the blood below a critical point, and you can loose conciousness.

This, incidentially is quite the opposite of what happens when breathing rapid and shallow underwater. (Since you're not venting the lungs properly, this leads to CO2 build-up which triggers the breathing reflex, and voila - The vicious cycle has begun)

 

[TSandM]

Good post, Bob, and I just want to reiterate that it takes TWO things to control rising CO2 levels. You MUST decrease your activity level, and you must increase your effective minute ventilation. The first is done by holding onto something and resting quietly; the second by making sure you are not using a shallow, panting respiratory pattern. It does not take very long to drop the CO2 levels if you simply breathe deeply and rhythmically, while REMAINING STILL.

Pilot Fish, you are right -- Unless you are using a full face mask, you can't really "vent" the way John is describing. But you have an advantage over the hard hat diver. Every breath you take on open circuit is pulling in clean, fresh air from the tank, which contains no CO2. The hardhat diver is breathing from the airspace around his face, which contains some of his exhaled CO2. This is why he has to vent, and wash that space clean. (Please correct me if I am wrong about this, John or anybody else.)

 

[espenskogen]

You have certainly covered a lot of ground on this thread, but I wanted to add a little something.

In commercial diving obviously the diver is physically working, often very hard. With the physical exertion comes the production of CO2. The CO2 does a lot of things. It combines with water to change the body's ph, making the entire body more acidic. It also stimulates the brain to increase respiration, and it undoubtedly does a bunch of other things that we do not even suspect as of today?

The point I am trying to make is that physical exertion, especially in the u/w environment, impacts the entire body, including the heart, lungs, brain and acid-base homeostasis.

In hardhat diving, divers constantly maintain an awareness of exertion, and overexertion. As soon as you begin to get winded, you let topside know you are going to "take a vent". A vent is simply blowing gas through the helmet free flow, to flush out any CO2, while the diver rests motionless, and topside monitors his/her progress. When you recover your breath, you return to work. Staying ahead of the wave is critical. Fall too far behind and you cannot recover.

I suspect the need to flush a hard hat, as TSands correctly pointed out, is due to the much greater dead air space in a helmet than in a recreational scuba regulator.
When you have a greater dead air space, there is a risk that when you're breathing, you're breathing mainly co2 from your previously exhaled breaths. This is obviously not good, and is why flushing is appropriate for full face masks and hard hats. Not so much for recreational diving with a standard regulators though.

The best way to deal with CO2 buildup as a recreational diver, is simply to chill out, and breath slow and deep. No need to overcomplicate it.

 

[pilot fish]

The best way to deal with CO2 buildup as a recreational diver, is simply to chill out, and breath slow and deep. No need to overcomplicate it.

Now you tell me? Wish you had been with me at 122ft.

 

[pilot fish]

John, I'm gonna guess that acid hemostassis is acid blood levels? Dr Lynne will know this stuff too.

A question, John C, I felt I got narc'd as well as having this ugly co2 level, [did not realize what was happening at the time], and I think that sent me over the edge. Is it possible, [some recent reading I've done on it sugggests that co2 leads to narcosis, as well as DCI ], that the CO2 led to the narcosis? Also, important point, has this ever happened to you, both things together, and how did you handle it?

 

[TSandM]

Pilot Fish, CO2 is narcotic, as well as causing changes in the blood acid-base status. So when you're deep and get loaded on CO2 as well as nitrogen, it will worsen your narcosis. And the high CO2 levels will add to the anxiety that many of us get with narcosis alone. It's a nasty combination.

The body has a very strong imperative to keep the pH at 7.4, and it controls this very tightly. This is one of the biggest reasons why increased CO2 levels cause so much anxiety and faster breathing. The body is trying very hard to return the pH to normal, because many processes, including muscle contraction and all electrical impulses, don't work as well in acidic environments.