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> > In current thinking - what are the half-times usually associated >with our various tissues. I.e. Which tissue *is* the 20min one or the >2min one or the three day one or whatever. > > If there's a good list somewhere I'd appreciate a reference >(paper not book if poss.) > > Thekingyewverymucjly in advance, > Jason, half-times are fairy tale stuff, they are a means of mathematical modelling and are not meant to be related to real tissues. Buhlmann tried to make the correlation between his tissue half-times and actual anatomical tissues, based on DCI symtoms, but this is a forlorn occupation. In anaesthesia, vapour and gas uptake is often defined by 4 or 5 tissue half times, representing in ascending order of half-times 1. lungs; 2. blood ;3. vessel rich group (includes well perfused tissues like muscle and brain) 4. fat (where gases and vapours of concern are highly soluble). Sometimes a fifth group (not necessarily in order) is added to account for diffusion limited gas uptake and release. You can use as many groups as you want: Buhlmann's ZH-L16 model used 16 tissue half-times, surely you could model anything you want with that many equations, I can't remember how many half-times the USN tables used by the time Des Grages had finished with them, about five, the probablistic modeling (USN, DCIEM and others) used in the last decade or so gets fairly good fit of DCI data with only two tissue half-times, you can get reasonable profiles for air dives assuming a single half-time controls DCI, and you can calculate no deco limits with no half-times at all (Rassbass) . So with this variation of workable models its hard to say "tissue compartments" relate to a real bit of your body. ps. sorry about the wrong return address I was sending out over the weekend regards, David Doolette ddoolett@me*.ad*.ed*.au*
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