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  1. #1

    UTD's ratio deco study

    So the results of the UTD deco study are out and 30/80 GF while shorter than UTDs RD profile was found to be better (in terms of the of the DCS stress markers measured).

    What do any DIR Explorers think?
    ah herro

  2. #2
    I've posted these elsewhere, but adding them here:

    This is how the profiles look as viewed through a Buhlmann lens:

    The standard GF profile:

    DecoGF.jpeg

    And the UTD profile:

    DecoAG.jpeg

    It's pretty interesting that despite being 11 minutes longer, all the lucky rabbit's foot-ery in the UTD profile actually makes it worse than the GF profile.

  3. #3
    Quote Originally Posted by huwporter View Post
    I've posted these elsewhere, but adding them here:

    This is how the profiles look as viewed through a Buhlmann lens:

    The standard GF profile:

    DecoGF.jpeg

    And the UTD profile:

    DecoAG.jpeg

    It's pretty interesting that despite being 11 minutes longer, all the lucky rabbit's foot-ery in the UTD profile actually makes it worse than the GF profile.
    I didn't read the report - how is "worse" defined?

    A badly designed study no doubt - how to separate the effects of time from shape for example? Clearly not what the result UTD were expecting ...
    ah herro

  4. #4
    I don't have access to read the paper either, but quoting Dr. Mitchell on the study design and outcomes:

    Dr. Simon Mitchell:

    The authors compared a ratio deco and GF30:85 approach to decompression from a 50m 25 min trimix dive with nitrox 50 and oxygen decompression. There were 51 dives (28 ratio deco and 23 GF deco) and the end points were venous bubbles and assays of inflammatory markers suggestive of vascular injury.


    Despite having a longer decompression the ratio deco profile was associated with greater production of inflammatory markers after the dive. The ratio deco profile produced grade 3 or 4 bubbles in 4/28 (14.3%) divers and the GF profile produced grade 3 or 4 bubbles in 2/23 (8.7%) divers. The differences in inflammatory marker production were statistically significant, but the difference in the proportion of divers producing high bubble grades was not.

    The ratio decompression profile puts greater emphasis on deep stops in comparison to the GF profile, and the results constitute further evidence that the "love affair" we had with deep stops in the early 2000s has resulted in over-emphasis of the strategy by some algorithms. For clarity, and to avoid misinterpretation, the study does not establish GF 30:85 as optimal decompression. It simply indicates an advantage for that algorithm over one which places more emphasis on deep stops.
    From this and other public info; basically UTD/AG came up with their 'champion' deco strategy for 25 mins at 50m on 18/45 with 50% and 100%, and this was compared to a standard GF profile for the same depth, bottom time and gasses.

    The UTD profile caused statistically significantly more inflammation marker production, and more (though not statistically significantly more) high grade bubbles. So, despite being 11 minutes longer, the UTD profile can conclusively be said not to be better than the GF profile, and there is some clear evidence that it is worse in indirect markers of decompression stress.

    Profiles taken from this video:
    https://www.youtube.com/watch?v=ziad0wxUXfs
    Last edited by huwporter; March 28th, 2017 at 09:22 PM.

  5. #5
    Do you have a link to the study?

  6. #6
    Quote Originally Posted by data2 View Post
    Do you have a link to the study?
    Although Diving and Hyperbaric Medicine makes everything available through Rubicon, there is an embargo of (IIRC) a year before it become publically accessible. Those with access through hospital or academic libraries may be able to get a copy more easily. (Having said that, I've asked for a copy from the British Library via my hospital library and am still waiting)
    Frankly, filling and servicing my own kit is almost as much fun as actually diving it...

  7. #7
    I might have access; what's the exact title and authors?

 

 

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