Comprehensive list of all accidents

teksimple

WOT? WOT?? I have to speak up here. Good point on the MCCR, UWSojourner. To be sure, using these data alone to associate the use of a CCR with a heart attack is very poor science, because there is absolutely no control over the many factors. Has any one proposed that the person who owns a CCR might be at more risk of a heart attack? CCR's cost a lot. People who are wealthy tend to hold higher stress positions, which increases chance of insulin resistance, the latter of which is directly linked to cardiac events in several studies. Not to mention sitting on one's ass posting on Rebreather World. That being said, WOB could contribute to cardiac events, much like the physical stress of deer hunting tends to increase the rate of cardiac events among deer hunters who tend to be out of shape. Personally, whether I was a deer hunter or a CCR diver, I would look at the much more important factors like physical health rather than the few extra J/l of exertion one might encounter, in my survival priorities for a hunt or dive.

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"I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson

AM

How many "deep" manual CCR dives have been done in relation to the number of eCCR deep dives? In what work related conditions? The deepest manual CCR dives that I know of have been in caves, therefore low to zero flow applications, generally compared with wreck diving conditions. This at least has some bearing on WOB and breathing rate, which is exacerbated by work at depth. How many manual units are in use compared to eCCRs? I would suggest that there are a fraction of manual active divers compared to electronic active divers.

The point about WOB *deep* is really not about exertion as such. It is about the capability of the machine to deliver a breathing environment suitable for depth. If WOB does not meet the required levels, this increased WOB in itself precipitates an increased breathing rate. As WOB goes up, a self-perpetuating cycle develops, whereby breathing rate goes up and it is this increase in breathing rate, caused by increasingly poor WOB/depth, that is the difficult situation to recover. Add a bit of exertion and this becomes exponentially worse. Dave Shaw being a classic case in point.

The difference in statistical incidences of heart attacks on closed circuit compared to open circuit is *considerably* higher. It is infeasible with a variance of this magnitude, to simply dismiss this as a statistical anomaly or to suggest it is related to physical fitness/job etc.

Regards

AnneMarie

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UWSojourner

Alex has posted stats on OC too. Can you point me to the OC studies providing the statistics you're referencing? Is it DAN info?

nigelh

Heart attack...
I was planning my Mod 1 back in 2000 so I booked it but on a Saturday with a couple of weeks to go I went diving and then at 5AM on the Wednesday morning I woke up with a heart attack.

Now at 5AM I don't think it was too stress related but I always feel being a 'heart attack' death on an Inspo missed me like a bullet through the hat. The problem is that those of us that have money to impulse buy toys like this tend to be in the at risk age group.

(OK it wasn't really an impulse buy, engineers are congenitally incapable of not researching things, but you know what I mean.)

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nigelh

York

That would be the million-dollar question. With the current data available it remains an assumption. If, for a moment, we assume your claim is accurate - ... your point is...? You're not trying to suggest that all eCCR accidents happend at depth in high-current siutations, are you?

agreed.

That would quite a leap. I suggest diffusion had/has something to do with it, not merely flow (my point being that this specific case was outside the paramters and realms of investigations considered here).

As far as I understood the arguments here, it was not dismissed as statistical anomaly. The question that was raised was whether a heart attack is CoD or MoD. I fear that statistics will not deliver the answer (I concurr with Charles ).

Great discussion, points well made A-M! I whole-heartedly agree with your statement regarding British wheather.

J

lizardland

DAN published some figures a few years ago where heart attacks were the major cause of death in 40+ yr old divers.

But again, who knows whether that's means or cause.

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hrdubwd

Of course ...

My point is that the calculations made are wrong (make that 99.999...%). It is not a case of waiting for enough to die, it is simply that the formality of the prediction attempted cannot be done with the data we have (or could realistically have), assumptions notwithstanding. What we have is an association between certain kinds of event and the equipment involved. This is entirely enough to trigger questions about equipment design, its usage, diving practices, and the people who dive that kit, including their purposes, quality of training, health and so on.

Consider CO-poisoning from gas-fired water heaters. Whilst a probabilistic approach could be taken, it is entirely inappropriate to do so. The association of death (with a clearly identifiable proximate cause, in this case) with those devices led to queries about installation, safety mechanisms, education of the user, and so on. Changes occurred. If I understand it correctly, the burst of problems with the Meg is a parallel situation. Calculating risk there is pointless.

One preventable death is enough to trigger those questions, and the onus is on the producer, the trainer, and the user to honestly appraise - and fix - problems. There is no other threshold for action. Denial is counterproductive. However, the deletion (or at least the tagging) of deaths that had nothing material to do with the use of a rebreather in any way except that it was used for the dive is a legitimate filtering.

The facts of the list may need some emendation from time to time, but the motive for its existence does not change, nor can the responsibility of anyone concerned be measured against some risk value when the deaths recorded are not stochastic.

BWD

York

BWD,
I very much agree with your main thread here. As far as I understood the intention, the statistics presented are part of a much larger attempt to model failure modes on xCRs. To date this is the most complete model published so far, and consists of a deterministic (cause-and-effect) as well as a stochastic (simplistic spread-sheet) component. Taken individually, the stochastic approach does not amount to much, but in combination contributes to completing the picture.
Your last paragraph
should be part of a health-warning (similar to those on cigarette- packages) attached to the spreadsheet. I now understand that it is the potential user inference that you were criticising. No argument here ...

Green sent, my friend - excellent exchange!
J

hrdubwd

Thanks,
BWD

Drmike

possibly the best post Ive ever read on Rebreather World (or anywhere)

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Cave diving is a sport
Wreck diving is a sport
Diving in general is a sport

'Rebreather diving' is not a sport
its the delusional obsession with a highly dangerous and often inappropriate piece of equipment