Tissue to tissue diffusion

[boulderjohn]

I have read Deco for Divers and quite a few other resources, and I have a pretty good understanding about the process of diffusion as blood perfuses the tissues. I understand the various theories of how bubbles in tissues grow or shrink as well. What I don't read much about is dissolved gas diffusion from tissues to adjacent tissues. I would think there must be places where very fast tissues are adjacent to very slow tissues, and my limited knowledge suggests to me that this should have some kind of effect, but I find nothing written about it. Perhaps I should take that as a clue that it is not an issue.

 

[Thalassamania]

"Fast" and "slow" tissues do not actually exist, they are theoretical constructs designed by modelers to provide a way to calculate what goes on in the body. There are some "tissues" that are "faster" or "slower" than others, but only in a very general and non-specific sense, e.g. blood vs. fat in a relative comparison, as opposed to, "blood is a 5 minute tissue while fat is a 60 minute tissue."

 

[ivobj]

As far as I understand, considering that the total deco time should consider up to the slowest tissue and as in the interfaces between slow and faster tissues, the deco time necessary will not be higher than the slowest of the two, these interfaces are not an issue whilw calculating deco time, if you make enough deco for the slowest tissues (shallower stops).

Other fact is that if a transfer occur it should always br from the slow to the faster tissue, because the last one has a higher absortion capacity, so that transfer will only help decompression.

Probably DAN doctors could give a more accurate explanation, this was what I studied about this subject.

 

[AzAtty]

You might try looking into the Kid-Stubbs model, which is the basis for the DCIEM tables. It's a serial model (hypothesizes that gas transfers from tissue to tissue). At the very least it would give you a starting point for additional research.

 

[Dr Deco]

There is the possibility that nitrogen could diffuse from fat to connective tissue. The empirical models account for this. It is not directly in the Haldane scheme of things.

I will be away on vacation until April 14.

 

[boulderjohn]

There is the possibility that nitrogen could diffuse from fat to connective tissue. The empirical models account for this. It is not directly in the Haldane scheme of things.

That's the sort of thing I was thinking about. I am interested in reading details about how empirical models account for this.

 

[Thalassamania]

They just add additional terms, each mediated by a tissue-to-tissue diffusivity constant that can be tweaked to fit.

 

[Walter]

"Fast" and "slow" tissues do not actually exist, they are theoretical constructs designed by modelers to provide a way to calculate what goes on in the body.

Which is why the term "compartment" replaced the term "tissue" decades ago.