Diving too carefully?

I was OC trimx qualified before I got my unit so used trimix for any dives in double figures.
I had to do a 45m dive on air as part of my course and was on another planet, a very happy one.
Bottom line is I have only ever once dived air dil to that depth and won't be in a hurry to do it again.
I had dived air OC a lot deeper than 45m and felt fine but on CCR all clear thought was out the window.
I now like to have my head at about 25m when on CCR.
 
Or gained the experience to do a 60m dive on CCR...

Regards

Reminds my of my 11th dive on my breather , stuck in a wreck and no dill just shy of 60m bummer , that's what you get for being a know it all **** wit . lol
 
Deralie,

A summary of the situation is:

Every diving medicine textbook in the world concurs that VGE may be harmful by crossing right to left shunts. These same books also note that VGE cause cardiopulmonary DCS. In respect of the latter a case has been discussed on this thread where every diving medicine expert involved (and the coroner's verdict) agreed the diver died of cardiopulmonary DCS desite a normal ascent. In designing their dive tables the DCIEM based their schedule selection protocol on VGE counts. Similarly, almost every current decompression research project uses VGE as a measure of decompression stress, working on the proven basis that more VGE is bad. I could go on....

On this background, Ross wishes to advance the notion that VGE are good. They are part of normal decompression. They do no harm. They do not cause DCS. They have been "ignored" for 40 years, and can continue to be ignored. The diver discussed on this thread could not possibly have died from cardiopulmonary DCS. I can only conclude that he pedals these ideas because there are several studies now that have shown that decompressions using the algorithm he sells or other bubble models (somewhat ironically) produce high numbers of VGE under the circumstances reported in those studies.

That's it basically.

Simon M
 
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Deralie,

A summary of the situation is:

Every diving medicine textbook in the world concurs that VGE may be harmful by crossing right to left shunts. These same books also note that VGE cause cardiopulmonary DCS. In respect of the latter a case has been discussed on this thread where every diving medicine expert involved (and the coroner's verdict) agreed the diver died of cardiopulmonary DCS desite a normal ascent. In designing their dive tables the DCIEM based their schedule selection protocol on VGE counts. Similarly, almost every current decompression research project uses VGE as a measure of decompression stress, working on the proven basis that more VGE is bad. I could go on....

On this background, Ross wishes to advance the notion that VGE are good. They are part of normal decompression. They do no harm. They do not cause DCS. They have been "ignored" for 40 years, and can continue to be ignored. The diver discussed on this thread could not possibly have died from cardiopulmonary DCS. I can only conclude that he pedals these ideas because there are several studies now that have shown that decompressions using the algorithm he sells or other bubble models (somewhat ironically) produce high numbers of VGE under the circumstances reported in those studies.

That's it basically.

Simon M
You forgot to mention that you don't have a model at all claiming that decompression is bad. Your examples are either not available to the public or irrelevant and weird special cases. You refuse to accept that if you design a model there will always be cases that are out of the model.

While I agree that ross has some commercial interests, I don't think that they are that strong. The products I know cover also other algorithms. And you forgot also to mention your own commercial interests....
 
Deralie,

A summary of the situation is:

Every diving medicine textbook in the world concurs that VGE may be harmful by crossing right to left shunts. These same books also note that VGE cause cardiopulmonary DCS. In respect of the latter a case has been discussed on this thread where every diving medicine expert involved (and the coroner's verdict) agreed the diver died of cardiopulmonary DCS desite a normal ascent. In designing their dive tables the DCIEM based their schedule selection protocol on VGE counts. Similarly, almost every current decompression research project uses VGE as a measure of decompression stress, working on the proven basis that more VGE is bad. I could go on....

On this background, Ross wishes to advance the notion that VGE are good. They are part of normal decompression. They do no harm. They do not cause DCS. They have been "ignored" for 40 years, and can continue to be ignored. The diver discussed on this thread could not possibly have died from cardiopulmonary DCS. I can only conclude that he pedals these ideas because there are several studies now that have shown that decompressions using the algorithm he sells or other bubble models (somewhat ironically) produce high numbers of VGE under the circumstances reported in those studies.

That's it basically.

Simon M

Here we have yet again... Mitchell is trying to put words in my mouth. Trying to twist matters out of context.

Don't you ever grow tired of trying to push your point using BS and semantics and deliberate efforts to make implied accusations and derogatory comments? How sad that you have to stoop to such pathetic tactics, just to get your point across Mitchell!


You say "that VGE cause cardiopulmonary DCS" ... really? How often??? About 1 in 100000000000000000 dives?

The truth is, we all have VGE. NDL divers have VGE. PADI divers have VGE. BSAC divers have VGE. Millions and millions of dives every year all have VGE, and surprisingly they don't all drop dead on the deck, clutching their chests. I guess they were just lucky hey? That is a fact that you cannot dismiss Simon.


Of course some people can't tolerate VGE because they have defective circulation systems. Obviously these people are not suitable for the higher stress of deco diving, and need to take an abundance of caution, or stay at the shallow end of the pool. Tough luck for them. No where is it written that everyone has a right to go tech diving.


Your efforts to hide your non-explanation behind a coroner's report, is weak. You have not, and seemingly cannot provide any realistic explanation of the physics or physiology that occurred (or the "massive" VGE you claim) to create such an extreme deviation and sudden death in this man, when he did a seemingly normal and trouble free and common dive profile.


You wrote "...could not possibly have died from..." those are YOUR words Simon... NOT mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!


You wrote "..their dive tables the DCIEM based their schedule selection protocol on VGE counts.." which is in fact, a meaningless bit of semantics that adds up to nothing. What really occurred was The DCIEM based their tables on the Kidd Stubbs model and previous DCIEM tables, as documented in their published report from 93.



You wrote ... "wishes to advance the notion that VGE are good" Those are your words Simon Not mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!


You wrote ... "They are part of normal decompression" Yes they are. And they are part of normal non deco dives too. Part of PADI dives and BSAC and nitrox and air dives, and every other kind of dive. The most shallow recorded dive with VGE was from just 3.3m. Your ignorance of this fact Simon is amazing. Perhaps you have some ulterior motive, or a need to demonize VGE and pretend they only exist in certain dives? Time will tell.


You wrote "They do no harm. They do not cause DCS." For 99.99% of divers, this is true. Your ignorance of this fact Simon is amazing.


You wrote "They have been "ignored" for 40 years," Also true. No model, no method, no plan in use today, has taken any cues in deciding the levels of supersaturation limits. The limits of SS is decided on the primary measure of SS levels and gas loads and DCS outcomes - not secondary information like VGE. The exception was that the DCIEM made a few checks against VGE to fine tune the Kidds Stubbs model.


You wrote "I can only conclude that he pedals these ideas because ...." Simon writes more insults, more malicious and antagonistic comment, and all of it pure BS. What is wrong with you Mitchell.




*****


The problem is we have a doctor / scientist, on an long term agenda to change the world to VGE based diving, by pretending the sky is falling. He twists facts, he ignores the truth, he adds hyperbole and exaggerations, he cannot tolerate other peoples opinions and tries to bully them out of the way using any insult he can get away with.


I think its about time Mitchell got told and enforced to change his bad attitude to others. If this guy can't make his point without insulting others, then maybe he shouldn't be here.
 
X181! said:
While I agree that ross has some commercial interests, I don't think that they are that strong. The products I know cover also other algorithms. And you forgot also to mention your own commercial interests....

Correct.

Sent from my PAP4500DUO using Tapatalk 2
 
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You forgot to mention that you don't have a model at all claiming that decompression is bad.

I have no idea what you mean by this. Can you please explain this statement? If you are referring to VGE, there is abundant evidence that high VGE grades are associated with an increased risk of DCS. You are obviously mates with Ross, just ask to borrow his copy of Bennett and Elliott.

You refuse to accept that if you design a model there will always be cases that are out of the model.

Actually, that is exactly what I am arguing, and what Ross appears to arguing against. He says the diver could not have suffered cardiopulmonary DCS because the there was not enough gas load according to his modelling. I (and every other expert involved in the case) say that this is a case which is "out of the model" as you put it, and that it is clinically and pathologically obvious that the diver suffered cardiopulmonary DCS "out of the model".

While I agree that ross has some commercial interests, I don't think that they are that strong. The products I know cover also other algorithms.

He sells VPM and spends most of his time on forums defending it, or trying to discredit any information that could be interpreted as negative in respect of VPM. You can interpret that however you like.

And you forgot also to mention your own commercial interests....

We all have commercial interests of one form or another. The crucial question is whether or not they are relevant to a particular debate. Since you have announced this, please be my guest and enlighten this forum what you interpret my "own commercial interests" (of relevance to this debate) to be.

Simon M
 
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I was OC trimx qualified before I got my unit so used trimix for any dives in double figures.
I had to do a 45m dive on air as part of my course and was on another planet, a very happy one.
Bottom line is I have only ever once dived air dil to that depth and won't be in a hurry to do it again.
I had dived air OC a lot deeper than 45m and felt fine but on CCR all clear thought was out the window.
I now like to have my head at about 25m when on CCR.

Hi Morgan,

Totally agree.

I dived the U861 (43m) a few times OC air, once on CC 20/20. Great stuff. Brilliant.
Then a couple of years ago I dived it on CC 11/67 - the dive I was supposed to use that on was canned due to weather. Wow. Just. Wow.
Deep air? You can keep it! Sure you can do it. What for? Helium is expensive, but on a rebreather it's cheap enough, and you make it back in value.

And that's without taking into account the safety aspect of having a clear head, and WOB, and CO2, and...

I do quite a bit of diving with a dive club. Mostly with the rebreather. Mostly above 25m. Dil is whatever is in the emptiest cylinder, possibly topped up with air. So it's usually mix, sometimes real mix. So what? Is it required? No. Not even necessary. Does it do any harm? No. Not even to my wallet. 20m, I'll use 20 bar from a 3L. That's what? 1 euro? 2? Pound, whatever. So why not?

Cheers,

Matthieu
 
I was OC trimx qualified before I got my unit so used trimix for any dives in double figures.
I had to do a 45m dive on air as part of my course and was on another planet, a very happy one.
Bottom line is I have only ever once dived air dil to that depth and won't be in a hurry to do it again.
I had dived air OC a lot deeper than 45m and felt fine but on CCR all clear thought was out the window.
I now like to have my head at about 25m when on CCR.

Should people start from day one mix in diluent. From day 1 means after you finished mod 1?
I am not arguing what you are refering about, but should you be in that range of depth for the first dives on ccr on your own ? We are not talking about deep air here, imho for the beginning of ccr diving you should stay in the shallows 20m max and there i do indeed not see the need of helium. If you want go ahead, no harm.
But more importantly start your adventure ccr gradually and shallow
 
Ross,

This debate has arisen out of your claim that VGE, even high grades, do not matter. That is what it is about, pure and simple. Against virtually every piece of published data and scientific narrative around this subject, you are unilaterally claiming that VGE do not matter. I am not going to let you rewrite established knowledge of diving pathophysiology on public forums where people come in an attempt to find accurate information, particularly since this disinformation has its roots in a commercial agenda.

You say "that VGE cause cardiopulmonary DCS" ... really? How often??? About 1 in 100000000000000000 dives?

Cardiopulmonary DCS is just one example of the ways in which VGE can cause harm. Yes, it is rare (thankfully). I have said that multiple times.

The truth is, we all have VGE. NDL divers have VGE. PADI divers have VGE. BSAC divers have VGE. Millions and millions of dives every year all have VGE, and surprisingly they don't all drop dead on the deck, clutching their chests. I guess they were just lucky hey? That is a fact that you cannot dismiss Simon.

And I have never tried to dismiss it. VGE (especially the lower grades) are common and well tolerated in the majority of dives. That is well established scientific fact. That does not mean all VGE (especially the higher grades) are benign. Indeed, there is overwhelming evidence they are sometimes harmful.

Of course some people can't tolerate VGE because they have defective circulation systems. Obviously these people are not suitable for the higher stress of deco diving, and need to take an abundance of caution, or stay at the shallow end of the pool. Tough luck for them. No where is it written that everyone has a right to go tech diving.

As I have explained to you on many occasions, the diving population is not screened for PFO and so your attempt to split the divers into those that have "defective circulation systems" and those that don't is effectively irrelevant. There are many such divers out there, and very few of them know who they are. Moreover, even if you did screen everyone for a PFO and eliminated those with one (as you have suggested) there would still be the potential for VGE to cause the same forms of DCS by crossing pulmonary shunts, and that potential exists in everyone.

Your efforts to hide your non-explanation behind a coroner's report, is weak. You have not, and seemingly cannot provide any realistic explanation of the physics or physiology that occurred (or the "massive" VGE you claim) to create such an extreme deviation and sudden death in this man, when he did a seemingly normal and trouble free and common dive profile.

Except it happened, and has happened on other similar occasions. Any experienced diving physician can relate such case histories to you. I'm sorry that reality conflicts with your theory, but in general what actually happens is indisputable, whereas theory is, well, just theory.

You wrote "...could not possibly have died from..." those are YOUR words Simon... NOT mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!

I think most would agree that this is what you have strongly implied.

You wrote "..their dive tables the DCIEM based their schedule selection protocol on VGE counts.." which is in fact, a meaningless bit of semantics that adds up to nothing. What really occurred was The DCIEM based their tables on the Kidd Stubbs model and previous DCIEM tables, as documented in their published report from 93.

Yes, of course they based their tables on a model. They then tested their schedules against an outcome (VGE) you claim the scientific community have been ignoring for 40 years. Moreover, they rejected schedules when the VGE grades were high (grades that you claim are not associated with harm). It is absolutely clear that you are confabulating your entire position; it is simply incompatible with reality.

You wrote ... "wishes to advance the notion that VGE are good" Those are your words Simon Not mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!

You have inferred this a number of times in various places. In this thread you said:

"High VGE is not a bad thing. It says you have an abundance of gas leaving the tissues and heading to the lung to be exhaled - that is of course exactly what is supposed to happen in decompression."


Post can be found here: http://www.ccrexplorers.com/showthread.php?t=18348&p=177713&viewfull=1#post177713

An abundance of gas leaving the tissue just like it is supposed to..... that is putting a fairly "good" spin on high bubble grades in my opinion.

You wrote ... "They are part of normal decompression" Yes they are. And they are part of normal non deco dives too. Part of PADI dives and BSAC and nitrox and air dives, and every other kind of dive. The most shallow recorded dive with VGE was from just 3.3m. Your ignorance of this fact Simon is amazing. Perhaps you have some ulterior motive, or a need to demonize VGE and pretend they only exist in certain dives? Time will tell.

As I stated in opening this post, my objection is to your claim that VGE are harmless. I am not ignorant of the fact that VGE occur in many dives where no harm arises. I have stated this in many posts and I refer to this phenomenon in many of my publications. You are trying to turn my argument that VGE can cause harm into an argument that all VGE cause harm, and I have never said that because it is clearly not true.

You wrote "They do no harm. They do not cause DCS." For 99.99% of divers, this is true. Your ignorance of this fact Simon is amazing.

See above. Also, it depends entirely on what grade you are talking about.

You wrote "They have been "ignored" for 40 years," Also true.

An incomprehensible lie. Virtually every piece of decompression related human research published in the last 20 years (except the NEDU work - and even they use it as a secondary outcome measure) has used VGE as the primary outcome measure. If the scientific community agreed with you, why would this be the case?

No model, no method, no plan in use today, has taken any cues in deciding the levels of supersaturation limits. The limits of SS is decided on the primary measure of SS levels and gas loads and DCS outcomes - not secondary information like VGE. The exception was that the DCIEM made a few checks against VGE to fine tune the Kidds Stubbs model.

A few checks?? Isn't this the "extensive testing" you have lauded the DCIEM tables for in the past?

Simon
 
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Quote Originally Posted by rossh View Post
You wrote "...could not possibly have died from..." those are YOUR words Simon... NOT mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!
I think most would agree that this is what you have strongly implied.

I am following this thread from day one and as someone with little knowledge in this field would not comment, but i have to tell you rossh, these are your words from day one. What agenda are you chasing?
You are not credible
 
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Deralie,

A summary of the situation is:

Every diving medicine textbook in the world concurs that VGE may be harmful by crossing right to left shunts. These same books also note that VGE cause cardiopulmonary DCS. In respect of the latter a case has been discussed on this thread where every diving medicine expert involved (and the coroner's verdict) agreed the diver died of cardiopulmonary DCS desite a normal ascent. In designing their dive tables the DCIEM based their schedule selection protocol on VGE counts. Similarly, almost every current decompression research project uses VGE as a measure of decompression stress, working on the proven basis that more VGE is bad. I could go on....

On this background, Ross wishes to advance the notion that VGE are good. They are part of normal decompression. They do no harm. They do not cause DCS. They have been "ignored" for 40 years, and can continue to be ignored. The diver discussed on this thread could not possibly have died from cardiopulmonary DCS. I can only conclude that he pedals these ideas because there are several studies now that have shown that decompressions using the algorithm he sells or other bubble models (somewhat ironically) produce high numbers of VGE under the circumstances reported in those studies.

That's it basically.

Simon M

Thought so.

Cheers
Deralie
 
Quote Originally Posted by rossh View Post
You wrote "...could not possibly have died from..." those are YOUR words Simon... NOT mine. Yet again you try to change other peoples comments, context and meaning, just to suit your self - how arrogant of you!
I think most would agree that this is what you have strongly implied.

I am following this thread from day one and as someone with little knowledge in this field would not comment, but i have to tell you rossh, these are your words from day one. What agenda are you chasing?
You are not credible

No. You are wrong. I have made no determination of this mans demise.

I simply request that the doctor explain his decision. So far he has not offered a valid or believable explanation of physics and physiology behind this to back up his claim of "massive" VGE, that fits the context of the dive environment. The only thing offered is one doctor pointing at associates saying he agrees with me. That's not an explanation, and in today's world its not sufficient.
 
I simply request that the doctor explain his decision. So far he has not offered a valid or believable explanation of physics and physiology behind this to back up his claim of "massive" VGE, that fits the context of the dive environment. The only thing offered is one doctor pointing at associates saying he agrees with me. That's not an explanation, and in today's world its not sufficient.
Ross, unfortunately life cannot be easily compartmentalised as you hope/think it can be. Sometimes things happen for which we have no clear explanation, we only have observations. With lots of observations, an understanding of their context and an ability to repeat them, then we can then start to develop an understanding by coming up with theories and testing them.

Much of the work I am doing in behaviour is not possible to do in a diving environment and so there has to be read across from controlled experiments, in sometimes different domains such as economics and decisions made there. In terms of DCS, some of the work which the community would like done is not possible for ethical reasons and therefore we have to collect observations and accept that we may not be able to prove them, despite them being contrary to what theories say should happen.

Regards
 
No. You are wrong. I have made no determination of this mans demise.

I simply request that the doctor explain his decision. So far he has not offered a valid or believable explanation of physics and physiology behind this to back up his claim of "massive" VGE, that fits the context of the dive environment. The only thing offered is one doctor pointing at associates saying he agrees with me. That's not an explanation, and in today's world its not sufficient.


No offense, but i think we do not follow the same thread. You might have your valid points but your rhetoric is more than arguable
 
Ross, unfortunately life cannot be easily compartmentalised as you hope/think it can be. Sometimes things happen for which we have no clear explanation, we only have observations. With lots of observations, an understanding of their context and an ability to repeat them, then we can then start to develop an understanding by coming up with theories and testing them.

Much of the work I am doing in behaviour is not possible to do in a diving environment and so there has to be read across from controlled experiments, in sometimes different domains such as economics and decisions made there. In terms of DCS, some of the work which the community would like done is not possible for ethical reasons and therefore we have to collect observations and accept that we may not be able to prove them, despite them being contrary to what theories say should happen.

Regards

But Gareth, Yes there is physics behind this, and I readily accept there is variations between individuals. But this man dropped dead after a normal dive. That's not a deviation - its something entirely different.

The prognosis given was "massive" VGE. VGE do not grow out of nothing. There has to be a gas supply to make them from. Simon described this as "massive" amounts. Where did the massive gas supply come from to make this massive event? Or did something else happen here? I cannot imagine or think of a scenario that has this man absorb double or triple the usual gas load that could explain this situation. There has to be some other explanation for this sad and unusual event. What is it I wonder? Anyone care to speculate?
 
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Safer? So is helium "dangerous" again too?



My shallow dil bottle is roughly 18/25. Using that to about 35-40m depending on what I have for bailout (usually air). Deeper than that I bring a different dil tank.
The only time I use air is topping off a trimix dil. I keep 10/50 banked at home, shallow diving is usually whatever is left in the dil sphere with a bit of air to boost the pressure. I've usually got a decent amount of helium in it on shallow stuff. It costs nothing, why would I waste gas by dumping it in favour of air?
 
No, you won't- you'd be Farm Animal level stupid to dive Mix dil at 6-20mtrs (which is what your early CCR dives will be) even down close to 40mtrs you are streets ahead safer/cheaper on Air dil (aka- Nitrox diving)

Ignore the internet warriors- on CCR Air dil is perfectly usable and the money saved pays for slime for more dives.
That'll be me then.

I hate using air diluent on any dive. I only keep trimix in my diluent bottles so should I bin that if I want to do a scallop bash at the end of the day or get asked to have a shallow dip at the local quarry? Absolute nonsense.

As for 'Farm Animal level stupid', that would be people using air dil at 'close to 40m' when they have other options. If it were my only option, I'd sooner not dive.
 
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