Deep Air survey

[Popeye]

MikeFerrara once bubbled...
One isn't enough you want more?

Yes, actually. You're the one to take a single death, cause unknown, and turn it into a trend.

Like the death you reported at Gilboa that was a heart attack. Or was it a murder?

MikeFerrara once bubbled...
How do you train to manage narcosis? Overlearn emergency procedures? That's part of it but you lose reasoning ability and that's what avoids problems. I have never seen any evidence that says you can train for that.

Can you reference a study that suggests divers can learn to reason under the effects of narcosis? So far your only argument is that lots of divers do it.

Since you can't relate to the empirical evidence of the entire history of diving (take, for instance, diving Truk lagoon on air for the last two or three decades), maybe the U.S. Navy will do.

Read section 3-10 of the Navy Dive Manual for the exact answer to your question.

 

[Popeye]

MikeFerrara once bubbled...
You are correct trimix doesn't eliminate narcosis but it is a very handy way of reducing it to a level that no one disputes is manageable.

<snip>

Can you reference a study that suggests divers can learn to reason under the effects of narcosis? So far your only argument is that lots of divers do it.

After posting that you dive narcosis free, this is yet another treat.

So, Mike, you now state that there -is- a level of managable narcosis?

Can you reference a study for that?

 

[MikeFerrara]

Give me a little while and I'll post some narcosis studies, what they showd and who did them. Maybe you will be willing to discuss them. I have a visitor and it will take a lttle while to type it in.

 

[Popeye]

MikeFerrara once bubbled...
Popeye,
I guess I don't care what the odds (deaths or injuries per num of divers) are because I believe that if we fail to avoid even one that is avoidable we messed up. The dead diver or their family will not excuse the poor training because theirs was th only loved one that got hurt.

Your not willing to discuss any data are you. You even suggest that I twist the DAN report? Yet you offer nothing at all.

I'm willing to discuss anything.

Well, Mike, you do twist the DAN report, so let's discuss it.

Keeping in mind this is a deep air thread, and nothing you've cited, including a 14 month old magazine article refers to narcosis, I'll try and make my point one or two questions at a time.

How many divers died in 2002, and how many of then were women?

 

[Popeye]

Popeye once bubbled...


I'm willing to discuss anything.

Well, Mike, you do twist the DAN report, so let's discuss it.

Keeping in mind this is a deep air thread, and nothing you've cited, including a 14 month old magazine article refers to narcosis, I'll try and make my point one or two questions at a time.

How many divers died in 2002, and how many of then were women?

Sorry, make that 2000.

 

[MikeFerrara]

The Dive Training article is ONE MONTH OLD sorry it was Jan. 2003. I'll go back and edit the other post also. The DAN report is for 2000. The run a couple years behind because of the time it takes to collect and process the data. It is the 2002 report. Yes I know I used the women. I didn't hide that fact. It of course shows a very similar trent as tha males but was easier to summerize. The trend is still valid I think.

 

[MikeFerrara]

Here are some studies specific to narcosis.

I am only including portions and study references. I must reduce the amount of typing. Feel free to post sections that you feel are important that I missed. I will try to sum it up as accurately as I can without typing the entire thing.

From the IANTD “Technical Diver Encyclopedia”

Tolerance and Adaptation.
Tolerance is the reduced effect of a drug with repeated exposure. In this context tolerance would imply a reduced narcotic potency of inert gas with repeated exposure, but this is apparently not the case since repeated diving exposure does not reduce the objective behavioral measures of inert gas narcosis.

Rogers W.H., Moeller G. (1989) Effect of brief, repeated hyperbaric exposures on susceptibility to nitrogen Undersea Biomedical Research; 16:227-232

Moeller et al., 1981 Performance effects with repeated exposure to the Diving Environment. Journal of Applied Physiology; 66:502-510

Subjective Adaptation
Adaptation is the adjustment by the organism to its environment; in the case of narcosis, adaptation would be a rearrangement of behavior that allows a performance enhancement. Repeated diving produces a disassociation of behavioral and subjective components of narcosis. It is unclear whether this represents a true tolerance or an adaptation. During 5 consecutive daily dives to 6.46 ATA on air, reaction time does not improve relative to 1 ATA, but subjective evaluation of narcosis does change. Global estimates of the magnitude of narcosis begin to decline by the 3rd daily dive as does identification of body/mental sensations associated with intoxication; however, subjects continue to describe their ability to work as being impaired. It is evident that it is inappropriate to use the intensity of sensations of intoxication sensation as a gauge for under water efficiency.

(Hamilton, et al., 1995) Disassociation of the behavioral and subjective components of nitrogen narcosis and diver adaptation. Undersea Hyperbaric Medicine; 22; 41-49

Specific adaptation and individual variability
really brief …It is possible to control accuracy on tests for narcosis allowing only speed to decline (Fowler, et al., 1993) Undersea Hyperbaric Medicine 20;49-62, so a potential strategic adaptation may be to choose an appropriate speed accuracy trade off.

Let’s discuss these aspects of narcosis then we can go on to Specific adaptation and individual variability (in more detail) and recommended strategies for dealing with narcosis. Is that agreeable? I skipped some sentences in the interest of brevity so feel free to fill in the blanks if you feel it’s important.

These studies appear to show that the ability to train to handle narcosis (reduce the effects) is a myth. Over repeated exposure the diver learns to feel better making him/her think they can perform better. You can fool yourself. It seems you can’t train yourself to be able to think (handle novel situations or situation that requires cognitive information processing) better under the effects of narcosis. What is your take on it? Do you have conflicting studies?

 

[Popeye]

MikeFerrara once bubbled...
Here are some studies specific to narcosis.

I am only including portions and study references. I must reduce the amount of typing.

Let’s discuss these aspects of narcosis then we can go on to Specific adaptation and individual variability (in more detail) and recommended strategies for dealing with narcosis. Is that agreeable? I skipped some sentences in the interest of brevity so feel free to fill in the blanks if you feel it’s important.

These studies appear to show that the ability to train to handle narcosis (reduce the effects) is a myth. Over repeated exposure the diver learns to feel better making him/her think they can perform better. You can fool yourself. It seems you can’t train yourself to be able to think (handle novel situations or situation that requires cognitive information processing) better under the effects of narcosis. What is your take on it? Do you have conflicting studies?

Mike, unless you can cite information that we (and everybody else) can evaluate in it's entirety, I have no opinion to offer.

I'm sure, if your argument is as widespread and ironclad as you insist, you can find an internet reference, like I did.

I have seen your partisan (which is kinder than saying deliberately inaccurate) presentation of alleged facts and experiences.

My point is not and has never been that narcosis can be overcome, but that each person experiences vastly different levels of narc, in different situations.

I will also clearly state, as you already have, that some levels of narcosis are tolerable.

I cited the Navy Dive Manual, which you can download for free and rebut. It says that some experience divers can function on working dives a 200, because of their repeated exposure to narcosis. It also says some cannot.

It doesn't say that they no longer get narced.

But unless you have a cite stating there is an invisible and debilitating wall of narcosis at precisely 130 ft, then your arbitrary rule means nothing.

Like I said.


Now, are you going to post the numbers I asked, or are you deliberately avoiding the question?

You indicate that 50% of women diver deaths occur between 90 and 120 ft, and this indicates a "trend".

How many divers died in 2000, and how many of them were women?

 

[MikeFerrara]

This is what I said...

"The report is only usefull for certain things. Nobody knows how many active divers there are or how many dives are done per year. Also reporting is good in the US but from some parts of the world little or nothing is reported to DAN.

I didn't give total numbers because I was pointing out trends (causes of injuries). In the other post I did give the total number of injuries/incedents and the percentages though

See here from a couple of posts ago

Of 728 incedents

More than half involved procedural problems on the part of the diver.
4% running out of gas
5% unspecified equipment problems
8% missed decompression
nearly 25% reported rapid ascents
More than 40% percent of those injured reported difficulty maintaining buoyancy

Nobody knows what the injury rate per total number of active divers is. What I am cincerned with is the cause and wether or not it can be avoided. "

"Trend" was not the best word to use but I also included a parenthetic "(causes of injuries)"

If your point is that the number of deaths is small I agree and the number of female deaths (from memery) like 6 is even smaller.

The number if injuries though is much larger see above.

I will look at what the Navy manual says when I locate the CD I have it on. We're in the process of moving the shop. I'm not going to down load it again because it took so long the last time. In the mean time since you don't like the studies I presented If you would like to quote something fron the Navy Manual that might be usefull.

 

[Popeye]

MikeFerrara once bubbled...
This is what I said...

"The report is only usefull for certain things. Nobody knows how many active divers there are or how many dives are done per year. Also reporting is good in the US but from some parts of the world little or nothing is reported to DAN.

I didn't give total numbers because I was pointing out trends (causes of injuries). In the other post I did give the total number of injuries/incedents and the percentages though

No, Mike, this is what you said (first):

"Page 57 of the DAN report shows that about 50% of the female fatalities were on dives to between 90 and 119 feet. While most may not think of this as deep in terms of narcosis I contend that it is too deep for many recreational divers. The same page points out that most fatalities seem to happen on the first day of diving and all but eight were on the first dive.

The report points out several other very interesting things like the number of dives in the previous year and the amount of training the injured divers had. Almost 100% of the female fatalities had between 0 and 19 dives in the prior 12 months. (page 53)

Page 52 about 30% percent of fatalities were divers certified for longer than 10 years. There is another big clump at 1 year and under and little inbetween

The report doesn't prove much about narcosis other than these divers don't need any but it sure seems to say something about the skill level of divers. IMO at least some if not most) of the blame should go to the way we train divers."

Now, stating that "50% of the female fatalities were on dives to between 90 and 119 feet" sounds terrifying, until we find out that this 50% is 6 divers. I find it hard to believe that you didn't intentionally leave that number out.

Then, you try to insinuate that this is narcosis related, and state "I didn't give total numbers because I was pointing out trends (causes of injuries). In the other post I did give the total number of injuries/incedents and the percentages though".

(the 728 injuries, which don't indicate narcosis either)

Now, explain how your "trend" is indicated with 6 deaths, especially with no historical context. Explain how this indicates "causes of injuries" when the report makes no indication of how, or why, these 6 women died. And it certainly doesn't indicate any narcosis, although it may well have been a factor.

Now, if you go by DEMA's year 2000 marketing estimates (I should have the latest info today), and PADI's overall numbers, we know that there are 8 MILLION certified divers in the U.S., and that 2.9 MILLION of them are active, assuming ONE DIVE PER PERSON, that's 6 deaths, of unknown cause, in almost 3 million dives (grossly conservative) that -you say- indicates a trend.

You are a grossly inaccurate alarmist, and it's becoming hard to assume it's accidental.


Forgive me if I don't have a lot of faith in your perception of statistics -or- your perception of the abilities of your fellow diver.


At this point, we are completely off topic. If you would care to further debate your 728 incidents, which I would love to, we need a moderator to split the thread.

I'll address your studies, more on topic, in another post.