Hypoxia

[rbdave]

I agree that I was very lucky and once the lights start to go it is too late however I was being effected prior to this and was already reacting when this happened.

Paul asked why I suffered dilution hypoxia. It was on a homebuilt RB which relied on counting breaths and manual injection. I did probably another 70 dives on the unit without electronics but started and finished on pure O2 which was much easier.

I'm now very careful about monitoring my ppo2 but I still enjoy diving by myself ( even after resuscitating an Inspiration diver that had drowned at 42 metres only 2 weeks ago)

Cheers

Dave

 

[caveseeker7]

rbdave once bubbled...
I'm now very careful about monitoring my ppo2 but I still enjoy diving by myself

By now you ought to know the risks better than anybody. But you might want to have a look at Madmole's write-up of Inspiration accidents. Quite a few happened on solo dives ... .
http://www.btinternet.com/~madmole/DiveMole/DMDanger.htm

rbdave once bubbled...
even after resusiting an Inspiration diver that had drowned at 42 metres only 2 weeks ago

What happened ? And why?

Good luck

 

[The Iceni]

Mverick once bubbled...
We used to do this as kids.

I am often amazed that the majority survive childhood intact!

I remain concerned that dilution hypoxia is a common phenomenon with all kinds of rebreathers, when combined with solo diving - another common rebreather practice - this can be fatal.

It would seem we still have a lot to learn about the physiology of rebreather diving.

 

[fins wake]

I'm now very careful about monitoring my ppo2 but I still enjoy diving by myself ( even after resuscitating an Inspiration diver that had drowned at 42 metres only 2 weeks ago)

I gather that Wino's Inspiration accident was due to hypercapnia, not dilution hypoxia? Perhaps merely a question of exceeding official scrubber times again? (I'm looking forward to his account when he gets well enough to jot it down, BTW.)

In any case, rbdave is not only an experienced RB diver and cave diver (you've done a few sumps, haven't you, Dave?) but also a guy I'd like to have around if I ever had an accident ... his EAR helped save the Inspiration diver's life two weeks ago ...

I remain concerned that dilution hypoxia is a common phenomenon with all kinds of rebreathers,

Could you expand on this, Paul? Not quite sure what you mean ... hypoxia in rebreathers is quite easily monitored ...

It would seem we still have a lot to learn about the physiology of rebreather diving.

Maybe still some issues, yes. But a lot is actually well-known. It's when this knowledge is not properly taught, learned and mastered that the problems appear. Often the basic rules are ignored ...

when combined with solo diving - another common rebreather practice - this can be fatal.

On this I agree entirely. The Queensland accident, the Sydney accident (MK15.5), the recent Norwegian Navy accident (SIVA 55), the Stockholm accident last year (Azimuth) all had happy endings because the divers essentially were not diving solo. This is not an anti-solo diving rant in general. For OC, it may have it's uses in certain circumstances (e.g. cave exploration, photography). But it does seem to increase the fatality rates for RB diving ...

 

[The Iceni]

fins wake once bubbled...
Could you expand on this, Paul? Not quite sure what you mean ... hypoxia in rebreathers is quite easily monitored . . . . . It's when this knowledge is not properly taught, learned and mastered that the problems appear.

Quite so! I am just concerned that I read of so many near misses with RBs. The fact that some appear to consider it is safe to RB solo without a O2 monitor begars belief.

 

[saturated]

I think all rebreathers should come in a box that says "brain not included". Diving solo is risky, diving solo with no way of knowing your ppo2 is just plain dumb. You my friend have been lucky. While I wont say I have never dove alone, I will say that whenever practical I have a buddy. When I do dive alone redudancy is the key, and checking my ppo2 every couple minutes is the zone. There are to many new Breather guys reading this board to advocate being reckless. Why not at least have an oxygauge. Case point, what if you are at 100', you have an emergency and need to ascend quickly. (Your left foot was just bitten and is bleeding). In all the confusion you forget that you have breathed your po2 down to .7. You begin your ascent. Now your po2 is dropping rapidly. You have no audible alarms, or gauges, so you dont know your po2. The emergency has gotten your brain focused on getting out of the water. At 50 ft your po2 is below life sustaining. As you hit the surface you are unconsious. The dive boat is 500' away picking up other divers. You may die on the surface from either drowning or hypoxia if the mouthpeice stays intact. Of course had you had a simple oxygauge and had the habit of watching it, you would have seen the problem as it progressed and probably lived to tell about it.

Sorry to get like this, but what we believe to be a similiar incident happened to a friend of mine in 86. We all have the It wont happen to me syndrom, that is exactly what kills people. If you dive blind, it is my personal belief and experience that at some point it will catch up to you.

For the sake of those that care about you, get a gauge and a buddy.

 

[caveseeker7]

Dr Paul Thomas once bubbled...
Quite so! I am just concerned that I read of so many near misses with RBs. The fact that some appear to consider it is safe to RB solo without a O2 monitor begars belief.

All eCCRs have them (and need to to get the mix), usually three sensors and two displays. The biggest problem ought to be cmf SCRs as you simply don't know exactly what you're breathing. And as I mentioned above, I can't believe that any of their manufacturers make O2 monitoring optional if available at all. And that divers use them without ... by the time they get through their training they ought to know better.

 

[rbdave]

Hi Saturated,

The homebuilt is long gone ( and had triple 02 sensors by the time it was replaced )

I now dive an Inspiration which has good 02 monitoring and I'm careful to check it.

Cheers

Dave

Gee, I hope nonbody bites my foot when I have 3 hours deco to go.

 

[fins wake]

Gee, I hope nonbody bites my foot when I have 3 hours deco to go.

Isn't Oz the place where you have to check under toilet seats for giant redbacks before you take a big one? And where the snakes are arguably less charming than the one in Harry Potter II?

 

[saturated]

Inspiration, way to go!

Sorry just do'nt want to see anyone hurt themselves needlessly.

congrats and welcome to the turtle family. Enjoy!

PS: Cary a turnicate.