Yes let put divers on ecmo to dive.
But more seriously, there is already a lot research done about possible consequences of the WOB of a regulator.
1 of the things they think can contribute (together with cold water) to IPE is the wob. A ccr breaths heavier than a normal regulator, even the ones that have met CE. Maybe you don't feel, but if you start to measure for sure. And they calculated/measured a difference between backmounted lungs and frontmounted lungs. All is physics. So theoretically a lung near your own lungs sounds best, like with a sidemount ccr. I own a sidekick, and I can tell you that this machine breaths ok when horizontal, but is a very crap breather when you are not horizontal. Forget breathing out when you are standing right up and forget breathing in when you are heads down completely. And also when I am swimming horizontal it breaths harder than my Inspiration with backmounted lungs.
The ADV of a ccr is most times a crap second stage if you would need to breathe from that every breath. They are only needed when you don't use the MAV, but they have really a high 'WOB' to get gas out (you cannot blow gas in like with a normal reg).
Some divers adjust their normal oc regulators as they believe that a higher wob will lower their gas consumption. This is not true.
Balanced regs breathe better than none balanced regs.
We can put helium in our breathing gas and then the WOB decreases. BUT, there is a limit on that. For example, if you go to 130m on a 6/72 diluent. The END is around 30m, so no problem. But the EADD, the equivalent air density depth is then 48m. So much higher than the END.
The oxygen part during diving is not an issue, you always dive on a higher PO2 than at surface normally, whatever you are breathing. You (normally) don't breath hypoxic gases at surface.
A ccr gives you at 10m depth most times already around 35% oxygen, and even air has then a PO2 of 0.42.
So preoxginating before a dive does not make sense, it will directly happen as soon as you take your head under the surface.
But the topic was about mechanical ventilation. If you want to fill a balloon under water, this is very hard due to physics. I am afraid that this will be the same if a person is not breathing anymore.
CPR tries to move the left oxygen in the body trough the body, so if you are a diver, theoretically you have some advantages. But performing cpr under water is also hard. And if you have to do mandatory decompression, your chances to survive lower fast. Even if you could manage to make the diver 'breath' with help from outside, how will you get the lips closed so that no water will enter? Even with a big cramp it is not completely sealed. And diving with a full face mask is not comfortable for all dives.
The best thing is not to get problems under water and not to need cpr or mechanical ventilation at all, also not at surface.
But I like the discussion about it. And remember, sometimes a stupid comment from someone can be chanced in a good idea and worked out to a working solution.
, I made an edit on a screen grab from
