Re: [Gnumed-devel] Free your mind with mindmapping

[Karsten Hilbert]

On Fri, May 08, 2009 at 02:33:58PM +0200, Hilbert, Sebastian wrote:

> While I am wraping my head around the details of the cardiac device pluging I 
> realize just how complex it is to get it right. The software i currently use 
> solves that by ignoring corner cases like a lead being implanted at the right 
> ventricular apex but being paced fom the atrial channel of the generator. It 
> does not cater for the case that a patient has an left ventricular and right 
> ventricular lead but both being connected to the RV channel through an Y-
> connector.

It often helps to ask oneself a few questions a la:

        What do I need to *compute* ?
        What do I need to *store* ?

Of course, in an ideal world one would model (store
computably, that is) everything. The pragmatic answer,
however, lies in the user stories:

> Why so overly complicated. Because you will want to know which of your 
> patients have a device

Note the question: which patient *has* a device of type X

> that has just been recalled 
That is outside knowledge being factored into the qestion.
It won't influence our model.

> or if the ICD shocks are related to the lead being flaky.
There's no way this can be answered by GNUmed regardless of
the model.

> You might also be interested in the fact that 
> the program you applied two years ago led to less shocks than the currently 
> active one.

That, to me, seems a more worthwhile thing to model.
However, it seems unlikely that this question will be asked
(outside of clinical studies) across populations - it will
rather mostly be interesting with regard to a specific
patient. Thus you can plot the "number of shocks" (assuming
you'd record that as a measurement - which can already be
done today) against a specific piece of narrative "current
device programming" relevant to that period of time. No
magic.

Note that to facilitate this we could add a, say, sOap field
to the GUI somewhere intended to record the current
programming - this would go into a standard sOap field in
the backend but would be tagged with a pre-defined type
beyond the SOAP labelling.

> The XML file is changing almost every minute a new thought comes up. I have 
> been toying with the idea of how to group devices. To do that one has to 
> define what a device is. I have settled for the definition that an ICD-device 
> is actually a virtual device consisting of a generator and a number of leads. 

Despite virtual somethings being very useful concepts in
briding reality and computer science this seems a very real
device to me: generator + battery + leads. Of course, the
whole is more than the sum of its parts so that's the
virtual aspect.

Most of the time the virtual something models a "fact" about
the patient while the meatspace things model as details of
an instance of the concept of that fact.

Hopefully everything less clear now :-)

Karsten
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