Slow tissue on gas from stops

[Storker]

How can you call a so called evidence based decompression model the only choice when its foundation is based on Disneyland profiles no diver will ever perform?

Did you read David Doolette's explanation of the experimental design they chose, which Simon already has linked to? In case you missed it, it's here. If you've read it, I seriously doubt that you understood it. As I've said upthread, it's a wonderful explanation of how to design an experiment to get a definitive answer to the question they were asking. It should be required reading for any Experimental Design 101 class.

 

[doctormike]

Which brings me to another of my favorite pet peeves. I have a colleague who walks with a limp and has a humpback due to polio when he was a boy. My parents never had to worry about their kids getting polio, because we were fed those pink drops on tiny pieces of crackers during primary school. OTOH, I still remember my mother checking up on us if we were developing a stiff neck when we had the measles, not being able to completely hide her fears. Me, I've never had to worry about neither since my kids were born after the measles vaccine had been introduced. These days, there are parents who choose not to vaccinate their children. They can't have had the same experiences I've had. It's rather ironic that the success of modern medical science has lead to this.

</hijack>

Preach it, brother! If that isn't worth a little thread hijacking, I don't know what is.

Two cousins in my family from my mom's generation died of diptheria in the early 20th century. Imagine telling their parents that there was a way to prevent that but people didn't want it...

 

[boulderjohn]

America's Lab Report is a scathing indictment of science instruction in America. I was once part of a committee that used it as a basis to formulate recommendations for including scientific investigations in online education classes. The committee chair, a professor from Northwestern, and I co-authored our conclusions.

ALR is a metastudy that examines the results of hundreds of earlier studies, concluding in part that science education does not include investigations (like labs) in a meaningful way and thus gives students a distorted view of science. They do not understand the process of scientific investigations. They see science as a long, long, long list of established facts that need to be memorized for a final exam.

Just as a few examples of the problems, labs are rarely integrated into the instruction--they are often on different topics from what is being learned. It's all a cookbook. The results are carefully controlled so that a very predictable result must occur--there is no real hypothesizing, no analysis of results. Since no mistakes are possible, there is no need for error analysis. In many cases, to avoid potential injuries, all labs are done as demonstrations by the teacher.

As a result, adults who graduated from such an experience do not understand why experiments must be designed in a specific way. They don't understand control procedures. They think conclusions are either 100% proven or 100% unproven--no middle ground can exist. They simply don't understand the process of science.

Most sadly, in one section they show why it is unlikely ever to change.

 

[doctormike]

As a result, adults who graduated from such an experience do not understand why experiments must be designed in a specific way. They don't understand control procedures. They think conclusions are either 100% proven or 100% unproven--no middle ground can exist. They simply don't understand the process of science.

Exactly. We are SO lucky to have this one tool that lets us pierce the darkness and actually discover TRUTH. And we treat it like it's just one more random cable news "opinion" that can be refuted by someone else shouting louder.

 

[Dr Simon Mitchell]

How can you call a so called evidence based decompression model the only choice when its foundation is based on Disneyland profiles no diver will ever perform?

The profiles in the NEDU study were chosen very deliberately by the most expert decompression science group in the world. The basis for their choices and the reasons why the results of the study are relevant to technical diving have been extensively discussed elsewhere. The post that Storker linked to is a good place to start. You have obviously not bothered to appraise yourself of these matters.

In addition, we are no longer talking about just the NEDU study. We also have the French study, the Spisni ratio deco study and a fourth comparative study by the Swedish Navy that is not yet published. All of these compared decompression approaches that emphasize deep stops against approaches that don't, in profiles that even you would consider much more real world than the NEDU study. The results in every one of them are exactly what you would predict based on the recent comprehensive appraisal of what you characterize as NEDU's "Disneyland" results. More decompression stress in the profiles that emphasize deep stops in every study. So far, "Disneyland" has been right on the money. If you want to cling to your pseudo-religious belief in bubble models then fill your boots, but don't be surprised when scientists point out the emerging science to the wider world of rational divers.

Simon M

 

[Storker]

We also have the French study, the Spisni ratio deco study and a fourth comparative study by the Swedish Navy that is not yet published.

Are those - with the exception of the yet unpublished one, of course - openly accessible to the general public, or are they paywalled? In any case, could you post the full references?

 

[Dr Simon Mitchell]

Are those - with the exception of the yet unpublished one, of course - openly accessible to the general public, or are they paywalled? In any case, could you post the full references?

Hi Storker,

Both in journals that are not available to the general public unfortunately. The Spisni study can be distributed after 1 year.

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

Bubble incidence after staged decompression from 50 or 60 msw: effect of adding deep stops. - PubMed - NCBI

Simon M

 

[Storker]

Thanks.

 

[Dan_P]

It's my experience that most of the people claiming with ultimate certainty that "deep stops are debunked" because nedu and science, can't point to a relevant reference and say what it concludes and how.
I find that most of the people who have actually gone through the hassle of purchasing access to, and reading, relevant material, tend to approach this matter with significantly less confidence.

To those prior, I offer the following retort:
So, you know deep stops to be a sham then, do ya?
Set your decometre to GF100/100 and crack on, then.

Spisni et al compared a lot of deep stop emphasis to slightly less deep stop emphasis [1]
NEDU did deep stop testing on deep air dives [2]
Blatteau et al did deep stop testing on deep air dives [3]
Schellart et al added extra deco and measured how that would pan out with that distributed deeper vs. shallower, respectively [4]

If on this basis one feels adequately confident to make a guess at the correct emphasis distribution across gas mechanics principles and dissolved gas principles, I'm sure that'd make for excellent entertainment once such a correct weighting is actually shown and proven.

[1]:
A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco.
Spisni, Marabotti, De Fazio, Valerii, Cavazza, Brambilla, Hoxha, L'Abbate, Longobardi.
Diving Hyperb Med. 2017 Mar;47(1):9-16.
A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco. - PubMed - NCBI

[2]:
Redistribution of decompression stop time from shallow to deep stops increases incidence of decompression sickness in air decompression dives
Doolette, DJ; Gerth, WA; Gault, KA.
US Navy Experimental Diving Unit Technical Report 2011-06
http://archive.rubicon-foundation.o...23456789/10269/NEDU_TR_2011-06.pdf?sequence=1

[3]:
Bubble incidence after staged decompression from 50 or 60 msw: effect of adding deep stops
Blatteau JE1, Hugon M, Gardette B, Sainty JM, Galland FM.
Aviat Space Environ Med. 2005 May;76(5):490-2.
Bubble incidence after staged decompression from 50 or 60 msw: effect of adding deep stops. - PubMed - NCBI

[4]
Bubble formation after a 20-m dive: deep-stop vs. shallow-stop decompression profiles.
Schellart NA1, Corstius JJ, Germonpré P, Sterk W.
Aviat Space Environ Med. 2008 May;79(5):488-94.
Bubble formation after a 20-m dive: deep-stop vs. shallow-stop decompression profiles. - PubMed - NCBI

 

[Storker]

people claiming with ultimate certainty that "deep stops are debunked" because nedu and science

Good job finding all that straw at this time of the year.