For CPR and chest compressions, the recommendation used to be mouth-to-mouth and timed compressions. People felt icky about putting their mouth on a "dead" person and it didn't really do much good. There was all that stuff about pressing in the right spot at the right rhythm and all that. Now the recommendation is "push hard on their chest", it's better than nothing. So, do the best you can. If you can't don't worry about it.
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This is not just about ickyness. Afaik the recommendation got changed as it has been shown that for most out of hospital arrests giving rescue breaths at all made very little difference to survival rates in adults - probably coz a)Most adult problems are caused by an initial cardiac problem rather than a breathing problem and b) People who try to do mouth to mouth and aren't (well) trained in CPR will usually do ineffctive breaths and waste too much time doing those while at the same time doing ineffective chest compression.
HOWEVER, if your co-kiter looks like hes about 25 years old I would seriously scratch my head as to why he suffered a cardiac arrest while kiting. I'd probably put my money on something like a seizure or a high impact knock out. In that case doing just chest compressions on its own are likely to be highly ineffective without trying to get some oxygen into their lungs first...
Either way, in all cases of arrests in water there will be a degree of drowning involved so do not skip mouth to mouth.
@lovelifeI havn't seen anyone loosing consciousness in water but here is what I'd probably do:
Ditch my board. Release their kite. Unleash from the bar (I have a switchblade, so not essential to be connected)*.
Wrap my leash below their arms and back onto the harness. If leash is too short for that then just connect to his/her harness. Keep him/her face up. Kite to the edge of the window and touch water, pray that there is enough pull on the kite and put right arm around his/her chest.
Left arm through the bottom of the bar and pull towards you. That will hopefully keep the kite powered and on the sea without bouncing around so you can now take your left hand and pinch their nose and tilt the head back a bit. Then rescue breaths until at shore. There is perhaps a chance that he/she is still breathing but you probably do little harm if you have good opportunity to give breaths.**
If its a sandy beach without rocks i would just keep bodydragging onto the sand (people are heavy, trust me...) then flag kite or pull safty. Then do CPR if no pulse/breathing and try to get someones attention.
No point doing chest compressions on the water. Won't work. If your mates head doesnt float close enough to your face while bodydragging and you can't get a seal with your mouth while pinching their nose there's also no point giving rescue breaths imho.
*realistically you need to attach yourself in one form or another if you are that far out. Just imagine what would happen if you bodydrag and let go by accident or because the other person is sort of heavy.
** Let's assume your mate had a seizure or was hit by a board on their head and your mate is wearing an impact vest and has got a kite with decent downwind pull so that the head was never underwater. In that case you only have to get them safely to shore and while they won't like you interfering with their breathing it will cause relatively little harm.