Ok so here's a scenario. It was triggered by reading Major Clangers thread Multiple Deco Cylinders and a few thoughts of encountering a tank dangling monster on a recreational dive. I'm a happy recreational diver, trundling on my merry way (presumably in company with others), inside my depth limits, and I come across a tech diver, or pair of tech divers that appear to be in difficulty. Lets assume that I/We'd like to help. Lets also assume for the present that they are OC equipped, are unresponsive, but are still respiring. I assume that if they are not respiring, getting them to the surface and O2 is their best chance, and a very very poor one at that. Comments please. (I'm hopeful I'd recognise CCR gear, and if this discussion proves fruitful perhaps that is another scenario we can consider) Simply taking them them to the surface, on the gas mix that are presently breathing may or may not be the best course of action. Comments again please. I can see at least two possibilities. a) They have passed out from O2 toxicity, in which case taking them shallower will help. b) They have passed out from lack of O2, for instance a missed gas change, and the mix they are presently breathing will not support consciousness at their present depth. in which case taking them shallower will worsen matters. c) Of course there may be another problem completely. Some questions to the Tech trained.. Are there universal means to tell what mix they are presently breathing, in order to decide which of those first two possibilities is likely? Is the risk of doing a gas change for a non responsive diver justified in any circumstance? (Either to a more appropriate gas from their stock if it appears that they have missed a gas change, or onto air or possibly EAN 32 or 34 nitrox from the recreational divers supply) Are there any circumstances where air or EAN at recreational levels would be actively harmful. Can that reasonably be given in all instances if they are out of deco gas for instance. I recognise that if they are on high O2 mixes then taking them shallower is an option to drop their PPO2, and if inspection of their present gas supply suggests that's what they are breathing, and especially if the PPO2 in the gas mix is excessive for their present depth, I guess that is the best course of action. Again comments please. If you take them up to a depth appropriate to the PPO2 that they are breathing, is it reasonable to remain at that depth for some time in the hope that they will recover sufficiently to at least communicate their deco obligation? How long is a reasonable time? Other than ensuring that they retain there regs, that their gas supplies are reasonable, that they continue to respire, is there anything else that can be done for them underwater? Other than getting a message to the surface, alerting the decompression and medical services, getting O2 supplies prepared and sounding the drums for qualified technical help, is there anything else that parties at the surface can do to assist? Harry
If you were their only hope, an instant but controlled direct ascent is the only course of action IMO. Anything other than that is guess work. You can fix a bend, you can't fix a drowning.
I'm assuming I can see respiration from their regs Suggsy, else I agree. I probably agree anyway. For recreational divers I would agree. Tech divers can (as I understand it) have deco obligations that are up towards the instantly fatal bend level, so I'm asking if this changes matters. Harry
You said in the op that they were still respiring. So if they are not breathing what good are they underwater? If they have deco, what deco schedule are you gonna follow. Surface them...
Deco obligations surely cant be taken into account in that type of scenario - you simply don't know what obligations there are. The only chance they may have is get them up and get them treated, what other option is there? Sent from my iPad using Forum Runner
Don't try and do a reg swap for them. If they have a reg in and breathing, they are not drowning, take the reg out and the likely outcome is a drowning. Get them up! If they are not breathing, sort out the best kit, stow it about your body and continue your dive.
at least have the courtesy to inflate them before continuing definitely take them up, breathing or not. there are far too many variables to take into consideration that makes it impossible to think about gas, deco etc... just get them to the surface.
Surface as safe as you can, as others have said drowning is pretty permanent, a bend (inmost cases ) can be treated. You have no idea what gas is what, if you can get a reg in use your own alternate as you know its a breathable gas all others are just a guess, then get them sunny side. As for their deco obligations they will drown they may get bent.....
Sort out any obvious immediate problems then get them to the surface. End of. Just think if you are diving properly with a pony, you could give both divers a reg and get all three to the surface with breathable air
