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Hi Peter,

> My point is this: You cannot accurately model the distribution and
> elimination of a drug without knowing the volume of distribution (Vd) in
> the body of that drug. You can't determine the Vd unless
> you know something about the size of that "body" i.e.,person. If the
> relative concentration of the drug is small in relationship to the volume
> of distribution, big variations in body mass can occur without
> changing the concentration greatly. A two fold increase in Vd halves the
> concentration, but if it goes from 0.008 mg/dl to 0.004 mg/dl, it probably
> won't have much biologic/pharmacologic effect. But nitrogen is present in
> high concentration in our bodies (~79%, maybe less). So differences in
> body size and so Vd are likely to play a *great* role in N2 elimination.

I appreciate where your coming from, and I understand your points.  
However, how will we manifest this in the practical world?  Will tables 
take into account the person's body mass?  If so, then shouldn't it also 
take into account exertion levels and other diver-independent variables?  
Maybe a model like this might come closer to predicting DCS, but I have a 
feeling that the quanitifiable variables aren't the most important ones. 
Maybe I'm overly pessimistic, but when you look at what Irvine gets away 
with, and then you look at people who get bent well within the tables, 
you have to wonder if black magic wouldn't be a better approach.

> I still think that the tables can be improved through the application of
> other medical disciplines, anesthesiology, physiology, pharmacology. I may
> be wrong, but I'll learn a lot trying.

I think you're probably right, but I think substantial improvements are a 
long way off.

Aloha,
Rich

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