Some Thoughts on Cave Diving Fatalities

[mgersch]

Rick and Bob,
I totally agree with you guys 100%.

It is great that we have the ICURR, but as has been mentioned, there is INTENTIONALLY no speculation and interpretation.

The problem is that we all DO speculate and make interpretations, but only speak of them quitely over beers at local restaurants after dives.

I know that I have personally spoken with my dive buddies about this and we never really seem to come to any useful conclusions.

Again, I am not knocking anyone and the IUCRR is a useful thing and a step in the right direction.

However, I also feel that as a community we can do better. Thanks for bringing this up Rick.

As an academic physician I would be glad to help be part of the solution (although admittedly I am not a specalist in dive medicine).

Along those lines, (but actually a sperate topic) I did a brief pubmed search and found very little. Does anyone know if these 3+ cases "oxygen toxicity" that occured at acceptable PaO2s are making there way into the medical literature? I didn't see any evidence of that. I think they at least deserve a case series. PM me if you have some information on this. I recently meet the Alachua county ME at a meeting. She seemed nice. I may ask her about this......

[BgDadddy]

Hey Mike, I was hoping you would show up.

If you can meet with the Alachua ME and get her onboard, or at least to agree with our idea of taking a closer look at these incidents, that would be a GIANT step in the right direction.

All we really need would be the results of the autopsy (which she could possibly help with) and a copy of the detailed police report for an incident and we can probably piece together the rest of the information to come to a reasonable conclusion with regards to what happened. The police report should be public record... not sure about the autopsy.

I'll give you a call tomorrow and we can discuss it further.

Rick

[bullfrog]

Where did the ox-tox info come from in the Jeff Thompson incident. I havn't seen that?

[BgDadddy]

It is pure speculation... but it's pretty much the agreed upon diagnosis made by us uninformed folks down here (at least until we learn otherwise).

Rick

[RN]

I may not know all the details, but from what I've heard about Jeff's case, it didn't sound like ox tox to me.

[BgDadddy]

ok... what do you think it might have been? (like I said... I have no idea other than speculation).

[mgersch]

you see, this is the sort of speculation that gets us nowhere.

All the info that any of us may have is 3rd or 4th hand at best.

I'm saying that a group with access to all the information, or at least the best information, should do a careful analysis, compare with other similar incidents if any exist, make commentary, and widely disseminate the results.

[bletso]

Sometimes the simplest explanation is the best, particularly since there are no competing arguments, and it would appear to be a reasonable explanation. (Occam's razor) After all, normal O2 limits were empiracally established. Also, most nitrox classes don't emphasize enough (IMO) long duration, multi-day exposures of high PO2. Therefore we don't pay as close attention to them!!

Dale

[Gary]

Doing some "rubicon"ing

"Screening for oxygen intolerance in U.S. Navy divers"
http://archive.rubicon-foundation.or...123456789/3046

During a recent experimental oxygen dive series at the U.S. Navy Experimental Diving Unit, three divers were noted to be reproducibly oxygen sensitive. These three divers were then given additional OTTs to see if any evidence of central nervous system oxygen toxicity would be detected by these multiple tests. The additional OTTs did not produce any signs or symptoms of oxygen toxicity in these already proven susceptible divers. A subsequent review of the records of the Naval Safety Center yielded a total of 1347 OTTs from 1 January 1972 to 31 December 1981. A review of diving accidents reported during this period revealed that 26 episodes of oxygen toxicity were noted during OTTs for a derived failure rate of 1.9percent.

Conclusions from this paper are: Screening for oxygen intolerance is complicated by intraindividual variation in oxygen tolerance; U.S. Navy diving using 100percent oxygen during the period studied has had an acceptable safety record according to the data on record at the Naval Safety Center; the OTT as currently administered by the U.S. Navy does not identify all individuals who are relatively susceptible to oxygen toxicity; those individuals who do fail the OTT are unusually susceptible to oxygen toxicity


So it seems that personal variability in susceptibiliy is a considerable concern and that for a small percentage of divers the limits may not be adequite. Also that testing would be unlikely to identify all unusually susceptible divers.

[Brian Kakuk]

I believe that the US Navy stopped giving O2 tolerance tests in the late 80s. It was deemed that day to day variances in indivuduals made the test inadequate.