PerroneFord changed my thinking, n maybe even saved my life.

[sschlesi]

After doing some studying and searching, I have become aware that there is an ENORMOUS amount of research that has gone into the "science of microbubble" offgassing, as expressed in modern day dive computer algorithems. My inclination is that I do not necessarily need to (at this stage) understand the science fully, to be able to appreciate it, respect it,...AND FOLLOW IT RELIGIOUSLY. That, and doing all the "basics" that we ALL know we should be doing (i.e. staying hydrated, staying warm, avoiding vassoconstrictors such as cafine and nicotine, avoiding alcohol...etc.) II can't honestly say I'm "relying" on ANYTHING to "protect me from DCS." What other options do we have than to BELIEVE in the research findings that have led to modern tables, TRUST the technologies that have captured those tables in algorithmic form, DO "all the right things" and then...simply DIVE and ENJOY?

I don't understand the science fully either. We have no options but to trust the established tables. I didn't mean to suggest there is a problem with the tables, the tables have been experimentally validated and are quite safe.

I was trying to point out that some of the theory which inspired the math for the tables is false, and it is not safe to try to draw conclusions based on that. The tables as a whole are validated and safe, it is much less safe to "de-construct" the tables and try to draw conclusions based on 1 or a few compartments within the tables.

 

[Blackwood]

I was trying to point out that it appears the tissue compartment theory has been proven wrong. If tissue compartments don't really exist, any conclusions based on tissue compartments make no sense.

I don't know if I draw the conclusion that tissue compartment theory is wrong from Dr. Deco's post. I draw that all the compartments are the same (i.e. one half life for all tissues).

I just wanted people who read this thread to realize that tissue compartments don't really exist. I suspect when most divers are introduced to deco theory they believe that tissue compartments are a confirmed fact.

I imagine it's always taught as theoretical. Otherwise we'd call them blood, fat, bone, skin, etc. rather than 5-minutes, 20-minutes, etc..

 

[Jrock1062]

great thread very informative thanks all

 

[emcbride81]

Apologies. Post edited.

 

[PerroneFord]

Oh come on. I did very little here. Can a mod lock this thread?

 

[InTheDrink]

Questions questions...

1. Are SB posters more risk averse than the diving population at large? Methinks yes. Please note I am not saying this is a good or bad thing.

2. Perrone is indeed well respected on this board from what I can see. Rightly so IMO. However, I do find it interesting that the tone of responders seems to vary greatly on a subjective basis. For example, the OP here could easily have been seriously flamed. Wasn't, which in my book is good. But inconsistency is REALLY confusing for people out there learning. I know this is the advanced forum, but there are still people learning big style, including the OP.

The other thing is that DCS seems to be over-rated. Even aggressive modes in computers are still quite cautious. Main things I've been hearing in terms of fatalities are:
1. eCCR Rebreathers
2. Heart/health issues
3. Training issues

in no particular order. DCS because of not fully observing stops doesn't seem to factor highly as a significant contributor to deaths reported/mentioned on these boards. Carelessness, poor planning and 'incidents' do. Seems to me like making sure you can mitigate these first three is more relevant than a minute here or a minute there in safety stops. If you're making safety stops you're probably already safe. Like I say, this is an observation rather than a dictat. And I am not saying safety stops/deco/etc. aren't necessary: I'm just saying that it seems to me that that's not the biggest risk.

J

 

[dumpsterDiver]

If tissue compartments don't really exist, any conclusions based on tissue compartments make no sense..

I thought tissue compartments are a mathematical approximation which facilitates the calculation of diffusion rates. How can a mathematical "model" not exist?

 

[scjoe]

Since there has been a reference to the Pyle article and NAUI extending the length of the deep stop, I thought I would just throw in the fact that the recent 2008 DAN study on deep stops seemed to conclude that absent a switch in the breathing gas, deep stops actually increase the risk of DCS.

There are theories, anecdotal stories and conflicting studies out there.

 

[sschlesi]

I thought tissue compartments are a mathematical approximation which facilitates the calculation of diffusion rates. How can a mathematical "model" not exist?

My original post in this thread (#37) was referencing another thread where Dr. Deco pointed out "There is experimental evidence to suggest (from me) that the tissues are the same and the halftimes are just a mathematical concept.".

The math of course exists, I was trying to clarify that doing the math for all the compartments in a model produces a valid result, but considering only one or a few compartments in isolation doesn't relate to any real tissue e.g. there is no approximately 5 minute tissue, or a tissue that is approx. 60 minutes. The tissues all behave pretty much the same and that behavior is approximated by the whole model.

 

[drew0930]

Since there has been a reference to the Pyle article and NAUI extending the length of the deep stop, I thought I would just throw in the fact that the recent 2008 DAN study on deep stops seemed to conclude that absent a switch in the breathing gas, deep stops actually increase the risk of DCS.

There are theories, anecdotal stories and conflicting studies out there.

Can you point me to the 2008 Dan study? Thanks