The Thomas-Gunther exchange has been very enlightening. My understanding of
HL7 has increased. Gunther, where is the best theoretical introduction to HL7
3 (that isn't just diagrams).
John Gage
Gunther Schadow wrote:
>
> Thomas,
>
> after reading your last message, I think GEHR and HL7v3 is very much on
> the same side. In fact, we already converged: GEHR came to include more
> specificity and HL7v3 has recently gone towards more generality. So,
> we now agree on the three level approach towards clinical information:
>
> (1) One concrete data structure
>
> information model, mostly graphically rendered in BON or UML.
>
> (Actually, if your BON-bubbles would show the attributes, and if
> the association lines were not so ugly double-fat, I would have
> no problem with using BON instead of UML. But not seeing the
> attributes is a real problem.)
>
> (2) Thousands of what both GEHR and HL7 call "templates" defining
> clinical collections of information.
>
> (3) A knowledge base (also called "master files," or "data
> dictionary") that define the observations, normal ranges,
> dosage instructuions, defaults, and those templates.
>
> Both GEHR and HL7 v3 have these three layers. I have not seen
> how GEHR maintains the knowledge layer and how GEHR maintains
> template definition. (I'm going to dis-regard the mentioning of
> XML DTD's in GEHR as a to-be revised mistake... this marketing
> hype makes all of us weak, I know. :-)
>
> In HL7 we have traditionally spoken of "master files" and still
> do so. But my vision has been to remove "master" tables from
> the model and merge them into the instance tables ... in your
> words, my belief is that a priori predicates and a posteriori
> predicates do have the same structure and that the semantic
> difference can be factored into a single code, which we call the
> mood code.
>
> Furthermore, I don't believe that subjective and objective
> a-posteriori predicates are structurally any different, in
> fact I even don't see the semantic difference, since there
> is nothing that reliably distinguished subjective from objective
> observations. Only circumstances (like who reported?, who
> witnessed?) that may make the distinction. Just try to label
> these as subj. vs. obj.: "HEART MURMURS", "PALPITATION",
> "PULSUS CELER ET ALTUS", "SCHIZOPHRENIA", "HALLUCINATIONS".
> What are your criteria?
>
> So, in HL7 v3 we do not make these distinctions in the
> concrete information model. Instead we represent all this
> attribution information with the medical record item, which
> we call Service. We believe that the professional action
> (Service) is in the center of the medical record. We believe
> that observations are just a specialization of actions (and
> hence I renounce CORBAmed's COAS, if only for it's name.)
> We also believe that the notion of Service Action is more
> powerful to standardize meaning than the concept of "Record
> Item". Everything can be an "item" but not everything should
> be a distinguished Service in HL7 ... at least what this
> Item/Service thing generally does should be clear without
> digging in a semantic network of 100000 entries.
>
> My favorite example for a non-observation and more-than-an-
> item is our Medication class with it's attributes. These
> allow you to express/share medical prescription data have in
> a stricly defined way, rather than having to make up bogus
> codes (or "headings") we use static attributes where we can.
> Table-drivenness is not a benefit in itself, we use it only
> if we have to. We have to for many things, but when it comes
> to largely quantitative phenomena, we may be able to do better.
>
> Some questions: is the home of GEHR Australia now and are you
> the chief modeler? Who else is in the GEHR group? What are
> your relationships to Europe and CEN's EHCRA (honestly, no
> fluff please)? Why has GEHR and EHCRA, who are so similar,
> been developed in two separate branches?
>
> If you track HL7 v3 work, would you be interested in sharing
> and getting into further collaboration to converge? Can you
> come to HL7 meetings? HL7 Australia (contact Klaus Veil or
> Dawid Rowed) may assist you in this effort.
>
> How married are you to Eiffel? It seems like a lot. I don't
> see Eiffel to become mainstream, even though it certainly is
> better than Java, it may be a path that leads into isolation.
> How well is GEHR portable onto other things than Eiffel, ...
> I know, you can always map, but impedance mismatch may render
> a good model difficult in another environment.
>
> Finally for now: what happened to the Units of measure
> between GEHR 1.0 and GEHR 2.2? Is it gone? Why? Are you
> interested in a replacement?
>
> regards
> -Gunther
>
> --
> Gunther_Schadow-------------------------------http://aurora.rg.iupui.edu
> Regenstrief Institute for Health Care
> 1050 Wishard Blvd., Indianapolis IN 46202, Phone: (317) 630 7960
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> ------------------------------------------------------------------------
>
> Gunther Schadow <[EMAIL PROTECTED]>
> M.D.
> Regenstrief Institute
>
> Gunther Schadow
> M.D. <[EMAIL PROTECTED]>
> Regenstrief Institute
> 1050 Wishard Blvd Fax: +1 317 630 6962
> Indianapolis Home: +1 317 816 0516
> Indiana Work: +1 317 630 7960
> 46202
> USA
> Additional Information:
> Last Name Schadow
> First Name Gunther
> Version 2.1
