Sudden loss of consciousness on an RB: Near-drowning and rescue

[Archangel]

Near-drowning and rescue
Hi all,

It has been a very interesting diving day!
Maximum depth:15m/50ft but most of it at 10m/33ft
Dive time: 50 minutes
Dive conditions: warm water, very mild current

This morning was supposed to be a nice and easy dive with another Meg
diver, an experienced trimix diver. At the end of the dive, we
planned to do a safety stop at 4.5m/15ft for 3 minutes but after 2
minutes, I saw him slowly turning on his back. Some strange thoughts
came to my mind:
"Why does he lay on the coral? he will damage it... but why did he
remove his mouthpiece?... He will flood his loop, the BOV is not
closed! ****!.... He's unconscious!!!"

Fortunately because of the very shallow depth, it took only a few
seconds between the moment I saw him and the moment we were back at
the surface. The guys on the boat reacted quickly and came to help
with a buoy and a rope. By that time, my buddy already regained
consciousness and started to cough, quite disoriented and with no
memory of what just happened.
I quickly checked his setpoint: 0.7 so hyperoxia and hypoxia can't
really be the reason why he passed out. No effort during deco and a
fresh scrubber, so no real risk of hypercapnia. His rebreather was
working perfectly and there was no problem noticed during the
pre-dive check-list. So why did he pass out?
The physician who extensively checked him later explained that the
lack of breakfast, the duration of the dive and maybe some lack of
sleep the night before might have trigger this black-out. Scary!!

Some interesting points can be noticed:
1- A neck strap or an FFM would have definitely helped to prevent the
loss of the mouthpiece.

2- This kind of problem can also happen to a solo rebreather diver.
No buddy nearby and this incident could have been more serious.

3- I practiced rescue scenarios hundreds of time with students, but I
still have the feeling that no one is ever prepared enough for this
kind of situation. As soon as the surprise is gone and your brain
understands and accepts the situation, you more or less works on
auto-pilot, using techniques you learnt and practiced. These
techniques have to be simple, flexible and well memorized. So
practice, practice, practice!

4- I was impressed by the reaction time of the boat crew. Again, the
fact that they are involved in rescue courses on a regular basis
definitely helps. They knew what to do, where was the o2 kit and how
to prepare it during the time we needed to come back to the boat.

5- My buddy is safe and, with the approval of the diving physician,
will go diving again tomorrow. But I'm sure he learnt his lesson and
he will never under-estimate how the level of fitness can vary daily
and how it can influence one's ability to dive, even for what we can
consider an easy recreational dive.

Hope sharing this experience can help someone else.

Cheers
__________________
Cedric Verdier

PADI Course Director
Mixed-Gas (CCR and OC) Instructor Trainer
ANDI-IANTD-PSAI-TDI-DSAT
Cave Diving Instructor Trainer

+++++++++++++++++++++++

I feel that this is important for all to see. All RB divers should dive with a team mate.

Tevis

[Zero]

Sounds like a scarey day for all. Could it have been low blood sugar levels?
Im in a bit of a mixed mind about gag straps. One they do hold the DSV/BOV in the mouth but will an unconscious diver still hold a seal around the edges to be able to breath? At least with it out the observer can see straight away somethings not right. The diver could be ingesting/inhaling small amouts of water every breath with the mouthpiece still in place. Just my thoughts on it. Glad everyones ok.

Matt

[acelockco]

Archangel
You say "But I'm sure he learnt his lesson and
he will never under-estimate how the level of fitness can vary daily and how it can influence one's ability to dive, even for what we can consider an easy recreational dive."

My thing is what lesson did he really learn. There was nothing that he did wrong. I have a strong feeling that something else caused his black out. Remember most Doctors don't know much or anything about the effects of SCUBA diving on an individual, let alone tri-mix or rebreather diving.

Bottom line, the only way to be 100% sure you will not be involved in a diving accident is to not dive. As you and I both know that is not an option for most of us.

[Finless]

AIUI, and I'm only a CCR interested person (not a user), but the symptoms sound a lot like hypoxia? Does a set point showing on the handset guarantee that is the mix he is getting?

FFM? Woohoo! I use one.

Solo diving ................. your friend could have had a black out anywhere with very serious consequences .......... driving a car or bike or skatebosrding or ..................? Does the doc def think the diving brought on the problem?

Anyway, the important bit is everyone is alive to dive another day. Good thing you were paying attention and not a photographer!

[The Publisher]

I think a huge lesson not yet addressed here is:

Cedric REALLY deserves some recognition as being a highly observant, responsible dive buddy.

Cedric, You Rock!

[acelockco]

That is true for sure!!!!

[Zero]

Whos Cedric?

Matt

[acelockco]

I think it is Archangel, you know the Z dude.

[acelockco]

Oops, LOL


I mean the V dude.

[Finless]

The physician who extensively checked him later explained that the
lack of breakfast, the duration of the dive and maybe some lack of
sleep the night before might have trigger this black-out.

That does not sound a very definitive diagnosis - "might have triggered ..........."? Is that your interpretation or the words the doctor used?