Definitely helpful if there was a BOV (there was), but not so sure of the benefit for a solo diver.
The
French military rebreather study showed an amazing survival rate (94% of divers who lost consciousness!), but it depended on a buddy being present. If you are solo diving and lose consciousness, I guess there might be a scenario where the diver could recover spontaneously. But for the most part, I don't think that the gag strap would make a huge difference. If you pass out from toxing or hypoxia when you are alone, that's probably not survivable even if the mouthpiece stays in.
Presuming a gag strap that has a lip shield (like the rEvo one), if the diver passes out as a result of toxing or hypercapnia (from overexertion - not a breakthrough), why would you not think they might live for an indeterminate amount of time, while passed out, simply because the loop is breathable, in their mouth, and not flooded?
I read the whole thread. I did not read anything that was at odds with the possibility that a gag strap could *possibly* have kept her alive until she was found.
Someone will correct me if I'm wrong, but I would dismiss the idea a gag strap would have changed the outcome. The purpose of the gag strap is largely for jaw fatigue during long deco and/or to buy time for a buddy to assist a diver that is toxing. You also have to remember that it takes a conscious human to control whether their airway is open or not. A gag strap would not do this for you and assuming you could get a perfect seal on the mouthpiece to keep water out while unconscious you would still likely embolize on the way up to the surface.
I think it's pretty safe to say that if you go unconscious while on a dive, 99% of the time you will not survive.
As above. When people simply pass out, they don't usually stop breathing (I don't think). Why should it be different under water? If they loop stays in and sealed against the diver's lips, and the nose stays occluded by a mask, it seems entirely possible that SOME conditions could result in a diver passing out but continuing to live for an indeterminate amount of time.
In particular, for someone who toxes, even without a buddy, if they are found on the bottom at 80 feet, an hour later, but the loop is in their mouth and not flooded, why is it that unlikely for them to survive? Why is it that likely that they would embolize if they happened to float to the surface? DCS? Sure. Lung overexpansion? Why?
FWIW, the rEvo mouthpiece/lip shield/gag strap does a pretty good job of holding the mouthpiece in and maintaining a seal. When I want to vent gas from my loop, completely relaxing my mouth and exhaling does not work. The gag strap keeps the lip shield in place and the seal is maintained. I have to go head up, to get my mouth to be the highest point in the loop, THEN relax my mouth as much as I can, tilt my head to the side, and then exhale. Even then, I can't get all the gas out. I don't think I could flood the loop on purpose, with the gag strap in place.
The dil was air, gases were analyzed, according to Buddy Dive staff.
The dil cylinder was air. But, is it confirmed that that cylinder was what she was actually using for her dil (versus using that for wing and using her offboard TX20/20 for dil)? Not that it makes a material difference to her ppO2....