Spiegel Incident

[Reg Braithwaite]

On ascent, be really careful with the inflator button. If air is needed, use multiple small puffs rather than one large one (thanks Lamont).

I'm fairly new to this, but so far my little experience has been that I never need to touch the inflator when ascending. In fact, I think I could disconnect it with confidence and orally inflate at the surface if need be. So far, what I do is let out some gas, then use my lungs and/or swim up to the next stop, then use my lungs to hold the stop, then let out some more gas and/or swim to the next stop and so on.

Am I doing it wrong (tm)?

 

[Blue Sparkle]

Hi Terry,

I think perhaps I did not phrase my previous response so that it read how I meant it. I was basically agreeing with you that "real" dive planning does get glossed over in OW.

I think that's because, well, there is only so much you can cover in such a short class, and there is a lot to learn. So the dives are essentially planned by default, i.e. 1 hour or 500 psi and at a site where it is not possible to go too deep (or you won't, anyway, if you stay with the instructor).

So when you are out on your own, you do have to "plan the dive and dive the plan," which this incident really hammers home.

I know that for myself (and I have taken OW twice), I will have to either take another, more advanced, class - or do some learning on my own - in order to plan more-complicated dives. I could use the tables to plan a single (or a series of) simple dives; but I could not go beyond that.

B.

 

[Blue Sparkle]

Reg,

I didn't mean to imply that one should or would even need to add air to ascend. I just took the point from the previous poster that if for any reason one *did* need to add air, to do it in short puffs instead of "one big" one.

I learned that one should swim up while deflating the BC. I think being overweighted might encourage one to add air at the start of an ascent (someone had speculated that perhaps Matthew was overweighted; I know I was a couple of times). So it's probably better form on your part that you don't need to.

But it seems like a good idea at any time (not just ascent) to add air in small puffs vs. larger ones. I think I had started to do that more as my two weeks of diving went on, and it worked much better, but it's always good to verbalize something, at least for me. Helps to make it a habit.

Sorry if I implied something that wasn't good technique. I'm rather new at diving

B.

 

[Scott L]

I'm fairly new to this, but so far my little experience has been that I never need to touch the inflator when ascending. In fact, I think I could disconnect it with confidence and orally inflate at the surface if need be. So far, what I do is let out some gas, then use my lungs and/or swim up to the next stop, then use my lungs to hold the stop, then let out some more gas and/or swim to the next stop and so on.

Am I doing it wrong (tm)?

Sounds like you are ascending while in horizonal trim and venting from the rear OPV. You were well trained!

 

[lamont]

Probably because although they followed similar profiles Matthew got hit very,very,hard but Andrew did not.

PFO is always a strong possibility when someone is badly bent for no obvious reason.

Here there may be a more obvious reason for the outcome, but the relative severity of the outcome, and the fact that a diver that was on roughly the same profile didn't require medical attention makes me suspect a PFO. Of course DCS is also all statistical and Matthew could have done the same profile a week earlier and walked away from it.

PFO is more plausible that the discussion about different decompression positions, though...

 

[DandyDon]

Probably because although they followed similar profiles Matthew got hit very,very,hard but Andrew did not.

PFO is always a strong possibility when someone is badly bent for no obvious reason.

And given that 25% of divers have one and don't know. Patent foramen ovale - MayoClinic.com

 

[bsee65]

Here there may be a more obvious reason for the outcome, but the relative severity of the outcome, and the fact that a diver that was on roughly the same profile didn't require medical attention makes me suspect a PFO. Of course DCS is also all statistical and Matthew could have done the same profile a week earlier and walked away from it.

PFO is more plausible that the discussion about different decompression positions, though...

They may not have had quite the same profile. They were both fishing and could have been at differing depths through the dive. Also, Matthew was a few hundred psi lower on gas, so he may have been more active and absorbed a bit more nitrogen. Don't forget that Andrew claimed achy knees at the surface as well. How close was he to taking a good hit?

 

[ianr33]

Its a common misconception but activity levels or breathing rates do not affect nitrogen absorption. Only thing that matters is pressure (depth) and time.

In my estimation there is a looooong way between achy knees and what happened to Matthew.

 

[Indian Valley Scuba]

Thank you for that comment, ianr33 Truly amazing how this thread has gone all over the place with analysis and conjecture of what happened inside tissues inside someones body.

True science is defined as being able to consistently produce the same results from an experiment. That will never apply to DCS, yet so many will firmly grip their own algorithms or believe that because the computer says I am ok, that I am not really in this wheelchair of chamber. Amazing.

 

[lamont]

They may not have had quite the same profile. They were both fishing and could have been at differing depths through the dive. Also, Matthew was a few hundred psi lower on gas, so he may have been more active and absorbed a bit more nitrogen. Don't forget that Andrew claimed achy knees at the surface as well. How close was he to taking a good hit?

Decompression isn't that exact. If they both did *about* the same dive, they both ran *about* the same deco risk. To have one diver be paralyzed and the other diver have "maybe an achy knee" is so wide that either its just a statistical anomaly out on the long tail (in which case there's no good explanation other than 'phase of moon'), or else I'd suspect a PFO. And to state my point really clearly, either there is either simply no explanation, or else look for a PFO (assuming the profiles were in the same ballpark -- all bets are off if Andrew was a 60 feet the whole time while Matthew was at 135). All the discussion of decompression position, workload, a little deeper/shallower/etc can't explain the very different outcomes.

And Andrew may also have a PFO, too. While bad type-2 DCS hits often involve PFOs, with 25% of divers having a PFO clearly there are many asymptomatic dives by divers with PFOs. Just because Andrew didn't take a type-2 hit on this dive, doesn't mean he can continue to do dives like this and avoid a type-2 hit.

But I would still bet that Matthew has a PFO and on this dive, the gas that shunted through the PFO and didn't go through the lung filter led directly to the severity of the injury. Anyone looking for an "explanation" should start there -- not with position, workload, minor variances in depth, etc.