Fiona Sharp death in Bonaire

[Dan]

Interesting reading:
OXTOX: If You Dive Nitrox You Should Know About OXTOX — DAN | Divers Alert Network — Medical Dive Article

The Table 2, below, from the above article, shows it'll take an exceptional exposure of 30 minutes at PPO2 = 2.0, before OXTOX.

View attachment 546472

If I could extrapolate the Normal Exposures data to PPO2 of 2.0 ata, the time would be 11 minutes to OXTOX

 

[wedivebc]

Right. But the scenario where a buddy light would be helpful wouldn't be the one that they described - non-rebreather divers observing some random CCR diver. I agree, they have no business trying to interpret a HUD that they are not trained to use.

The idea (as implemented by JJ and on some Meg models) is that there is a unique alert that indicates a PO2 out of range, that is visible to a buddy. All that means is that it's not a bad idea to check to see if your buddy is normally responsive, and responding to the alert. I don't see the problem with that. I really wish that Shearwater would stick one of those on the back of the NERD, that's the one downside of swapping out the stock HUD.

In the case shown in this video, the fact that the buddy noticed an alert (on the wrist controller) may have saved a life. If the diver had his controller rotated to face him, it might not have been noticed until it was too late:

Exactly, and when I am teaching I have my students point the LED straight up so that both the student and myself can see the output, but of course I am trained on the use of a HUD.
In that video the diver ignored the RED warning numbers on his PO2 display and would have also ignored a rapidly flashing (although not obvious in the video) HUD as well. Looks like a diver who should go back to OC.

 

[Peter69_56]

I was pointing out why people, especially "old timers", lie to a computer.
Hell there weren't really even commercial tables that people actually dove as recently at 2000, they were constantly experimented and tweaked with. "Normal" is not a static thing and it sure as heck isnt defined by bulhmann and gfs which everyone seems to think it is lately

Wasn't a criticism of you, was just a general comment for post readers about pushing boundaries and the simplistic view of, it worked for me last week so all good, maybe I can go a little further etc.I know how easy it is to push boundaries (as I sometimes do it, but try and offset this thinking by remembering Normalised Deviation, so as to not go down that slippery path)

 

[doctormike]

Exactly, and when I am teaching I have my students point the LED straight up so that both the student and myself can see the output, but of course I am trained on the use of a HUD.
In that video the diver ignored the RED warning numbers on his PO2 display and would have also ignored a rapidly flashing (although not obvious in the video) HUD as well. Looks like a diver who should go back to OC.

Oh, yeah... the failure was totally on that diver, don't get me wrong. And it's different, because in that case, the high PO2 hadn't affected his ability to respond to an alert, so it's not quite the same situation as someone who is losing consciousness from hypoxia.

But we often do things to mitigate the chance of human error, like call and response checklists. I mean, isn't that the argument for a gag strap? So that your buddy has a chance to save you (94% survival of the 54 cases with LOC in the Gempp paper).

You're a CCR instructor, of course I respect your insight, but I do see the advantage of a buddy light. It's a pretty minimal, unobtrusive thing, and it doesn't add much in terms of cost or complexity. I think that the Ouroboros rebreather has a PO2 readout on the back for a buddy or instructor, but the JJ and the Tiburon HUD cap is very simple.

 

[Remy B.]

{ Confused }

From what I have read of all her friends in the medical community, one of hear colleagues in Perth a female friends that happen to dive with Dr Fiona as a buddy see mention she was deaf, that is why she had a loud voice, that made her very noticed around in a gathering.

 

[wedivebc]

Oh, yeah... the failure was totally on that diver, don't get me wrong. And it's different, because in that case, the high PO2 hadn't affected his ability to respond to an alert, so it's not quite the same situation as someone who is losing consciousness from hypoxia.

But we often do things to mitigate the chance of human error, like call and response checklists. I mean, isn't that the argument for a gag strap? So that your buddy has a chance to save you (94% survival of the 54 cases with LOC in the Gempp paper).

You're a CCR instructor, of course I respect your insight, but I do see the advantage of a buddy light. It's a pretty minimal, unobtrusive thing, and it doesn't add much in terms of cost or complexity. I think that the Ouroboros rebreather has a PO2 readout on the back for a buddy or instructor, but the JJ and the Tiburon HUD cap is very simple.

I just bought a tiburon,and really like it. I see certain advantages of the buddy HUD but the demonstrated disadvantage is when an uninitiated diver perceives a problem based on the HUD readout where none exists.

 

[doctormike]

I just bought a tiburon,and really like it. I see certain advantages of the buddy HUD but the demonstrated disadvantage is when an uninitiated diver perceives a problem based on the HUD readout where none exists.

100% agree!

 

[Bob DBF]

You're completely missing my point. You interpreted a red flash to indicate an abnormal condition when in fact there could be any number of reasons a person would allow the PO2 to drop slightly on a dive without any concern to the diver.

The bigger question, I guess, is whether one should intervene into what one sees as a possibly dangerous situation. Having seen people, above and below the surface, so focused what they were doing they lose awareness of other things, including personal safety, I would rather be labeled a dumb ass than overlook the situation.

Probaby fodder for a different thread, but where would you draw the line, find out what is going on or just let God sort it out.


Bob

 

[doctormike]

The bigger question, I guess, is whether one should intervene into what one sees as a possibly dangerous situation.

The context of this subthread was two non-ccr divers observing the gear of a random rebreather diver that they encountered, with which gear they had no training or experience. So not sure that this is a case where they were obligated to do anything.

 

[wedivebc]

The bigger question, I guess, is whether one should intervene into what one sees as a possibly dangerous situation. Having seen people, above and below the surface, so focused what they were doing they lose awareness of other things, including personal safety, I would rather be labeled a dumb ass than overlook the situation.

Probaby fodder for a different thread, but where would you draw the line, find out what is going on or just let God sort it out.


Bob

I remember following a diver years ago who had a J valve on his tank. The lever was in the upper position but the actuating rod was disconnected. I was tempted to alert the diver to the situation but as I thought it through I wondered what signals would I use to communicate this situation. And what if the diver was aware of the position of the lever and maybe I should mind my own business. I did keep an eye on him throughout the dive and when I mentioned it after the dive he demostrated how he could reach the valve without the actuating rod, "but thanks anyway"