How much risk was I at for DCS?

[Jim Lapenta]

He followed the DM like a good little sheep. Got separated somehow. His profile shows a sharp descent just after hitting 100 feet. SPECULATION is he got narced and didn't realize what was happening and in that state was trying to locate the DM. But the results don't lie. Autopsy report listed COD as Arterial Gas Embolism with Nitrogen Narcosis and Central Nervous System Toxicity as contributing factors.
The DM/guide whatever you want to call him clearly stated that the plan was safe and "we do it all the time" on the way to the dive site according to the witnesses I spoke with and subsequently trained.

Sent from my DROID X2 using Tapatalk 2

 

[boulderjohn]

He followed the DM like a good little sheep. Got separated somehow. His profile shows a sharp descent just after hitting 100 feet. SPECULATION is he got narced and didn't realize what was happening and in that state was trying to locate the DM. But the results don't lie. Autopsy report listed COD as Arterial Gas Embolism with Nitrogen Narcosis and Central Nervous System Toxicity as contributing factors.
The DM/guide whatever you want to call him clearly stated that the plan was safe and "we do it all the time" on the way to the dive site according to the witnesses I spoke with and subsequently trained.

1. So was the problem that the DM led a dive that would was outside of NDLs and could have caused DCS (the topic of this thread), or was it that the diver failed to follow the DM? (Yes, I know that he clearly didn't he the diving skills for the dive, but that is another issue.)

2. How did the autopsy show nitrogen narcosis and central nervous system toxicity as contributing factors? I was not aware that either one could be detected in an autopsy.

 

[Jim Lapenta]

Yes. The divers were led on a dive with an increased risk of DCS by a DM that knew he had newer divers on board. And the problem was not that the diver failed to follow the DM but that he did in the first place without a plan of his own. Of course the dive shop that they did their classroom and confined water training in Colorado Springs told them that they would be fine as long as they listened to the DM and did whatever they were told. The fiance of the deceased stated that she did not recall more than mention of DCS and narcosis in the classroom portions but did remember being told their recommended depth was limited to 60 ft. Unless they were with a DM or Instructor. Her recollection.

As to the contibuting factors you would have to ask the ME in Grand Cayman. But I would hazard a guess that he was familiar with diving. It would be a logical progression to follow his reasoning. At say 100ft (or shallower) the diver begins to experience narcosis. Perhaps severe enough to seriously impair his judgment to the point where he does not realize that he is dropping faster and faster. At some point the air in his tank becomes toxic as the PPO2 level rises and he takes a CNS hit. Convulsing he continues down until for whatever reason at 342 ft he stops and begins to ascend. Maybe enough of a buoyancy swing from the now empty al80? Who knows? All that is known is that he did begin to ascend at that point and at 302 ft turned into a rocket and did an ascent that took just under two minutes.

I use this in every OW class I teach when we are talking about physiology, physics, dive planning, and DCS. As well as the other nasty things that can happen to one who does not have their own dive plan and follows it. Or who elects to do "trust me" dives. Especially those with a DM or even Instructor that the divers do not know and does not know them. Outside of some con ed classes anyway. Because students may not know the instructor if they choose to not train with their original OW instructor. And even then in OW classes when you have one doing pool and another doing checkouts without a chance to get to know each other, that raises at least yellow flags with me.

 

[boulderjohn]

As to the contibuting factors you would have to ask the ME in Grand Cayman.

I don't know what the ME might have said in conjunction with an autopsy, but I find it hard to blieve taht an ME would report in an autopsy two findings that cannot be found in an autopsy.

But I would hazard a guess that he was familiar with diving. It would be a logical progression to follow his reasoning. At say 100ft (or shallower) the diver begins to experience narcosis. Perhaps severe enough to seriously impair his judgment to the point where he does not realize that he is dropping faster and faster. At some point the air in his tank becomes toxic as the PPO2 level rises and he takes a CNS hit. Convulsing he continues down until for whatever reason at 342 ft he stops and begins to ascend. Maybe enough of a buoyancy swing from the now empty al80? Who knows? All that is known is that he did begin to ascend at that point and at 302 ft turned into a rocket and did an ascent that took just under two minutes.

I use this in every OW class I teach when we are talking about physiology, physics, dive planning, and DCS.

I am simply astounded that you or anyone drew this conclusion about this dive.

1. There is no evidence of CNS toxicity because the only evidence would be someone witnessing it, and no one did. To assume it happened because of the depth ignores the fact that many people have gone to that depth and beyond without a CNS toxicity problem. The ill-fated dive in Cozumel last year went to 400 feet without it happening.

2. Do you really think someone going through a grand mal seizure while dropping rapidly at more than 300 feet is suddenly going to have a swing in buoyancy from an emptying AL 80 tank that will suddenly propel him to the surface? The difference of a couple of pounds of weight is going to overcome all that loss of buoyancy? Have you ever gone past 300 feet rapidly and seen how much gas you have to add to your BCD just to slow your descent, let alone start a return trip to the surface?

 

[TSandM]

I hate to say it, but from personal experience with autopsy reports, lots of things get in them that are only from history or presumption.

 

[boulderjohn]

I hate to say it, but from personal experience with autopsy reports, lots of things get in them that are only from history or presumption.

Sorry to hear that. Hopefully more informed readers can tell the sublime from the ridiculous.

 

[supergaijin]

Working as a DM in the Philippines, Malaysia, Thailand, Egypt, Djibouti and New Zealand, I was quite often the only diver with a computer. Like it or not, this is very, very common in the diving world where the diver is instructed to not dive below the guide as part of their NDL briefing. This will not stop anytime soon I'd imagine. In the Maldives, diving with either a computer or tables is required by law.

While the above account of a diver losing himself to bad buoyancy control and subsequently 'the rapture', there is also nothing to suggest that such a tragedy would have been averted had the diver been diving with a computer. If divers do not process the information on the screen, the computer isn't worth their weight underwater. This novice diver sinking 300+foot before hitting the BCD inflator sounds like he had problems so basic, that having a computer wouldn't have helped. His issues were with depth control. I agree that such a diver shouldn't be diving that deep as a planned dive.

A sharp descent at 30m (to me) indicates a typically overweighted diver that never inflated the BCD while descending in a 'passive panic', who finally breathed out because the body demanded fresh oxygen and dropped like a stone.

 

[Tigerman]

Working as a DM in the Philippines, Malaysia, Thailand, Egypt, Djibouti and New Zealand, I was quite often the only diver with a computer. Like it or not, this is very, very common in the diving world where the diver is instructed to not dive below the guide as part of their NDL briefing. This will not stop anytime soon I'd imagine. In the Maldives, diving with either a computer or tables is required by law.

While the above account of a diver losing himself to bad buoyancy control and subsequently 'the rapture', there is also nothing to suggest that such a tragedy would have been averted had the diver been diving with a computer. If divers do not process the information on the screen, the computer isn't worth their weight underwater. This novice diver sinking 300+foot before hitting the BCD inflator sounds like he had problems so basic, that having a computer wouldn't have helped. His issues were with depth control. I agree that such a diver shouldn't be diving that deep as a planned dive.

A sharp descent at 30m (to me) indicates a typically overweighted diver that never inflated the BCD while descending in a 'passive panic', who finally breathed out because the body demanded fresh oxygen and dropped like a stone.

The diver shouldnt have been on a site where he could reach that kinda depth in the first place and thats the one massive fault made - taking him there..

 

[supergaijin]

I agree. A diver's first dives after a hiatus should be very simple shallow dives. If the diver lacks basic skills such as descending under control, they shouldn't be taken to deep walls.

I also dived Barracuda Lake while in Coron.

The OP's profile was a bit misleading I believe which made KevRumbo pull out his RockBottom calculator faster that you can say "Happy SAC".

Starting pressure: 210 bar
Ending pressure: 100 bar
Bottom time: 40 minutes
Maximum depth: 26.4 metres
Safety stop: 5 metres for 3 minutes

I believe the total dive time was 40mins including safety stop. Probably there was a heavy breather in the group which explains the short dive. The guide (probably) dropped them down to depth, then brought them shallow, staggering the ascent as is typical in the tropics.

Guides do not intentionally blow off deco obligations hoping for a tip. This is rediculous.

Lying to guests about depth and time? I have seen it happen when guides (usually doing 'intro dives') don't want to spend a long time underwater. In Egypt it was quite common to hear guides bragging about how they could pass off a 20min 'try dive' when in reality it lasted 12mins or less. I've heard max depths exaggerated almost every time a diver has a drink in their hand.

 

[Tigerman]

Bragging about passing 12 minutes off as 20 is not only REALLY bad service, its also really not smart if the wrong people get wind of it..
As long as you exaggerate the depth to be DEEPER its not that bad - when you start saying its a lot SHALLOWER than it was, you have a problem..

My previous post btw did referr to the 300+ foot dive, but it does kinda apply to the 26.4m dive as well.