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Originally Posted by Polorutz
your get brain damage aproximately 5 minutes AFTER the SWB...
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I head that a few times before (usually with a 4 minute time) and I think it is wrong. Or atleast it is based on a wrong assumption.
I think what medical science claims is that brain damage starts 4 minutes after lose of life functions, I don't remember if it's referred just to breathing or also to circulation (does anyone remember?).
Hypoxic blackout is different from that anyway, a person who got a heart attack (for example) would probably have his (artirial) blood saturated to 90-100% and his tissues saturated with O2 as well when the clock starts. In the case of an hypoxic blackout the blood is already at 60-40% (or even lower), and his tissues are probably far from saturated, on the other hand the heart is still circulating blood so there's different PPO2 in the brain per that saturation percentage. I don't think the occasional LMC/BO generates brain damage, but I think that the 4 minute assumption is wrong. (I also doubt the 4 min assumption for normal medical cases but I admit I didn't look too far into it).
I think it is safe to say that brain damage occures sometime after blackout, and that the safety's first priority is to get the diver breath again ASAP.
