Slow tissue on gas from stops

[Diver0001]

I don't know what you mean with that; are you saying the Spisni study wasn't a scientific study?

That's exactly what I'm saying. It was an EXPERIMENT but it was not a scientific experiment.

AG announced prior to the dives that the conclusion would be to prove how much better RD is than Buhlmann (even Buhlmann 30/80). An actual scientist NEVER goes into an experiment with a foregone conclusion. In science conclusions are drawn based upon evidence, not upon conviction.

It was very much supported by UTD - logistics and divers, etc. - and UTD adjusted practices with the findings from it.
I don't understand why you're saying the Spisni study was unscientific and asinine...?

I honestly don't even know how to respond to this. Have you been to university? Do you know how actual science is conducted? I sincerely don't want to insult you but what you're saying here makes no sense at all....

I'm saying it doesn't matter what I think of AG, or JJ, or Sheck, or Simon, or John, or anyone else for that matter.

Maybe I respect Simon, but argue with him anyway,
or maybe I think Simon is an evil mastermind, but acknowledge solid points anyway.

It doesn't matter what I think of him. It has nothing to do with that.
Except it does look personal in some cases, which is why I said something about it.

I appreciate that you think it gets personal and I respect that you're not willing to just let that slide. I'm sure I wouldn't either. That said, sometimes things sound personal but they're not as personal as they were intended. John, for example, is pointing out facts that aren't easy for some UTD divers to accept. It's pointing out facts but isn't personal... but it is TAKEN personally because when one feels invested in the propaganda being the truth.

I'm not saying that I don't understand the impact history can have. But I wasn't around for the DIR wars, so probably there is some legacy there still haunting that I'm not being sensitive to.

I was ... and I agree with you. It may be forming my thinking too.

R..

 

[Kevrumbo]

. . .An actual scientist NEVER goes into an experiment with a foregone conclusion. In science conclusions are drawn based upon evidence, not upon conviction.

That's fine. Scientists make mistakes too. . .

Bruce Wienke of the RGBM Model made that mistake, and had a seemingly compelling argument in this monograph on deepstops:

http://tecvault.t101.ro/Deep_Stops-BW.pdf
The first four paragraphs in the above linked article are particularly damning and now "cringeworthy" (the claim that deepstops can result in the overall shortening of decompression times -it's no wonder we haven't heard from BRW in a while. . .) all in the context of the unexpected results of the NEDU Deepstops Study.

http://tecvault.t101.ro/ModernDecompression_Wienke.pdf
To be fair to Wienke, he did offer this additional "rigorous" comparative examination of the various decompression algorithms, especially highlighting the min-max problem of dual phase mechanics: the compromise solution that RGBM attempts to solve using Bubble Theory along with neo-classical Haldane and Buhlmann tenets. (And this is what Ratio Deco attempts to emulate as well).

In hindsight:

. . .Bruce has never been short of equations! But its all just theory (albeit and attractive one that many of us fell in with at the time). What was always lacking was evidence that deep stop approaches were more successful than the methods they largely replaced. The vague references to a low incidence of DCS during use of RGBM in the first of those documents linked to by Kev does not constitute such evidence. For a start, there was never any clear description of the methods by which the "data" was gathered, nor did it appear to come from proper validation studies (which require that an algorithm is dived to its limits). For example, if 5,000 dives without DCS were made by divers notionally using RGBM but not diving it right up to its limits / ceilings, then that is not proof that the algorithm works. A lot of imprecise language was used around that time. It was not until proper comparative experimental work comparing different approaches was performed that the problems started to be seen.

Simon

Unfortunately it's not standing up to the latest research viz-a-viz the implications of the NEDU Deepstops Study and others listed above. . .

 

[Dan_P]

That's exactly what I'm saying. It was an EXPERIMENT but it was not a scientific experiment.

AG announced prior to the dives that the conclusion would be to prove how much better RD is than Buhlmann (even Buhlmann 30/80). An actual scientist NEVER goes into an experiment with a foregone conclusion. In science conclusions are drawn based upon evidence, not upon conviction.

I honestly don't even know how to respond to this. Have you been to university? Do you know how actual science is conducted? I sincerely don't want to insult you but what you're saying here makes no sense at all....

How can you say this?

The Spisni Study is commonly called the Spisni "Study" because it was in fact a scientific study, published in Diving Hyperbaric Medicine under reference 2017 Mar;47(1):9-16., titled "A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco." and accredited Spisni et alia.

You can't possibly say that it's not a scientific study, I'm simply not having it.

This is one of the most pivotal pieces of scientific work relating to this whole conversation, and indeed, debate.

I don't mean to insult you, but did you even bother reading the report?

EDIT:
Linked to here:
A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco. - PubMed - NCBI

I appreciate that you think it gets personal and I respect that you're not willing to just let that slide. I'm sure I wouldn't either. That said, sometimes things sound personal but they're not as personal as they were intended. John, for example, is pointing out facts that aren't easy for some UTD divers to accept. It's pointing out facts but isn't personal... but it is TAKEN personally because when one feels invested in the propaganda being the truth.

"invested in propaganda being the truth" is every bit as biased a statement as any on here.

I've said on numerous occations that I have zero buy-in towards any specific level of deep stop emphasis, and fully acknowledged that a standardized paradigm (deco, gas or both) can only rarely if ever at all, be optimal in any case.
AND, mind you, I have also stated that I don't have a problem with the statements presented by Dr. Mitchell on the matter, previous in this thread, too.

I find that saying I'm taking it personally because I'm invested in propaganda, quite frankly, is a tad insulting.

Personal, obsolete, onesided narratives with clear bias against UTD, less so, I'll admit.

 

[LiteHedded]

Try to follow this.

When I was with UTD, I was a student 100% of the time. I had to do what I was told.
If I left UTD, I would lose my job.
When it got to be too much, I left UTD, and I lost my job.

If that makes me a worthless, spineless piece of scum in your book, then so be it.

utd is garbage. we get it. everybody knows they hurt your feefees
sounds like it wasn't a job worth having anyway.

 

[boulderjohn]

utd is garbage. we get it. everybody knows they hurt your feefees
sounds like it wasn't a job worth having anyway.

No, UTD did not cost me my job. Leaving it to cross over to another agency cost me my job.

I do not crusade against UTD; I do not initiate these things. I react to others who promote its specific faults as if they were virtues. When I do, I think about my former UTD training partners who did buy into it when I didn't. Most accepted on faith that what they were being told to do was safe. I can't help but think that one of them would be alive today if he had not been taught to accept those dictates on faith. I just want others to see the value of using evidence-based decompression procedures rather than faith-based procedures.

 

[cathal]

the apparent logic then goes that any bubble model, RD and almost all GFs save one - and we don't know which one, mind you - are all "defective".

Bearing in mind the conclusion of the Spisni study you have referenced:

"CONCLUSION:
The ratio deco strategy did not confer any benefit in terms of bubbles but showed the disadvantage of increased decompression-associated secretion of inflammatory chemokines involved in the development of vascular damage"
​

Can you kindly point out your source for this 'apparent logic that almost all GFs save one are defective'?


Regards


Cathal

 

[Dan_P]

Can you kindly point out your source for this 'apparent logic that almost all GFs save one are defective'?

They're not, that's my point.
The problem I was highlighting with that post, is using "defective" and "imperfect" interchangeably, as any GF (or rather, approach) that isn't "the perfect one", would have to be labelled "defective". It would be misleading.

Functionality and perfection aren't mutually interdependent.
In fact, with tongue in cheek, one could even argue they're mutually exclusive, but that's obviously a non-diver's game.

No, UTD did not cost me my job. Leaving it to cross over to another agency cost me my job.

I do not crusade against UTD; I do not initiate these things. I react to others who promote its specific faults as if they were virtues. When I do, I think about my former UTD training partners who did buy into it when I didn't. Most accepted on faith that what they were being told to do was safe. I can't help but think that one of them would be alive today if he had not been taught to accept those dictates on faith. I just want others to see the value of using evidence-based decompression procedures rather than faith-based procedures.

Okay. I don't mean to be this insensitive about it - and I do apologize for that, I'd wish ill on noone - but at this point, with this practically being soft speak for "UTD killed my friend", frankly it's quite unacceptable;

First of all, the people involved were well prior expelled from UTD, were they not?
Second of all - you told me this story before - based on your own narrative, saying the least, it's extremely unlikely that decompression had anything to do with this:
Not "it wasn't Ratio Deco" - rather, "it wasn't decompression".

 

[boulderjohn]

First of all, the people involved were well prior expelled from UTD, were they not?
Second of all - you told me this story before - based on your own narrative, saying the least, it's extremely unlikely that decompression had anything to do with this:
Not "it wasn't Ratio Deco" - rather, "it wasn't decompression".

One was expelled for a technical issue. He was still devoted to its principles. My reference was to taking things on faith rather than evidence. They undertook a very much faith-based dive at high altitude, and most of that faith was based on another article of UTD faith that had been strongly driven into them during their (our) training--altitude does not have to be considered for dive planning. When I talked to the survivor more than a year later, he still scoffed at the idea that altitude needed to be be given serious consideration in their planning. From what I know, I am quite certain it was the primary reason.

 

[Dan_P]

One was expelled for a technical issue. He was still devoted to its principles. My reference was to taking things on faith rather than evidence. They undertook a very much faith-based dive at high altitude, and most of that faith was based on another article of UTD faith that had been strongly driven into them during their (our) training--altitude does not have to be considered for dive planning. When I talked to the survivor more than a year later, he still scoffed at the idea that altitude needed to be be given serious consideration in their planning. From what I know, I am quite certain it was the primary reason.

I'll leave it up to you if you want to share the details for discussion, as what I'm refering to was sent in a private message - which I'll respect - but I must say, from what you've shared with me around it, I find it extremely unlikely that decompression in general, or altitude for that matter, had anything to do with it, if I'm honest.

 

[Dr Simon Mitchell]

That's exactly what I'm saying. It was an EXPERIMENT but it was not a scientific experiment.

AG announced prior to the dives that the conclusion would be to prove how much better RD is than Buhlmann (even Buhlmann 30/80). An actual scientist NEVER goes into an experiment with a foregone conclusion. In science conclusions are drawn based upon evidence, not upon conviction.

Hello Rob,

Just a point of clarification here, in fairness to my Italian colleagues. There is no doubt this was a scientific study. Myself and other experts in the field consider it to have a significant design flaw in that they had two profiles of different length (RD deco was longer) which would have made it impossible to conclude anything if the RD profile had proved superior. But setting that aside, the thing that has created an understandable degree of confusion for you and others about the scientific provenance of the study was Andrew's self-indulgent insinuation of himself into the study narrative in that video. I suspect he had very little to do with it. He was not an author on the paper. I also suspect that my colleagues would have been cringing (and very likely outraged) over the confident prediction of superiority for RD before the results were known for exactly the reasons we see playing out here: that is, it made everyone involved look biased and unscientific.

In fact, notwithstanding my reservations about the study design, I congratulate the authors on reporting the results objectively in the context of obvious pressure from the participating dive organisation (that video being evidence of this) to report the outcomes as favourably as possible for RD.

Simon M