Thursday, October 16, 2014

On a Process for Rapid Template Development

Recently a question crossed the Structured Documents Workgroup List about how to record information about a patient's recent travel.  You can probably guess what recent media events motivated that question.

IHE had long ago developed a template for foreign travel, as part of XPHR. Since this section wasn't required in the HITSP C32, it was not further developed in C-CDA.  However, that doesn't stop anyone from using it, even under Meaningful Use.  The Foreign Travel template is simply a section containing a narrative description of travel.  Narrative capture of travel history is what most EHR systems today support.  This usually appears somewhere in the social history section of the patient chart, and is accessible to any provider caring for the patient in most EHR systems.

For cases of communicable disease, if you want the EHR to be able to apply clinical decision support to recent foreign travel, you would need coded entries, or natural language processing over the narrative.  To code the travel information, you will need to do more in this section.  The basic activity being documented is travel, and so you could readily capture that in an act, with location participants for each place visited.

<act classCode='ACT' moodCode='EVN'>
  <code code='420008001' displayName='Travel'
      codeSystem='2.16.840.1.113883.6.96' codeSystemName='SNOMED-CT'/>
  <effectiveTime><!-- This might be optional, see participant/time below -->
    <low value='Starting Date for Travel History'/>
    <high value='Ending Date for Travel History'/>

  <participant typeCode='LOC'>

The participant would represent the various locations visited during the time period described in the travel act.  We need not go into the entity level since participant.role can capture what we need.

<participant typeCode='LOC'>
    <low value='Starting Date for this Location'/>
    <high value='Ending Date for this Location'/>
  <participantRole classCode='TERR'>
    <!-- This might be optional, and could identify locations using a value
         set such as Geographic Location History -->
    <code code='Code identifying location
      codeSystem='Code System for Locations (e.g., ISO-3166)'/>

We would probably want to constrain participantRole so that only one addr element was present (and was mandatory), and had at least one element of city, county, state or country.  I would also recommend that country always be present, and that if city or county is present, that state also be present.  For disambiguation purposes, you might need to know which of the twelve New London's in the US your patient was recently in.

Some have suggested that location could be rolled up into a code, as I have shown above in participantRole/code.  While I agree that would make certain kinds of decision support easier, it is something that could be done within the clinical decision support module, rather than being specified within the EHR.  The Geographic Location Value set referenced above shows why this might be a problem, as it contains codes describing locations at different levels.

So, now back to the main point.  We quickly went through this model on the Structured Documents workgroup list service in less than three days.  It would take us several months to role this out as a new template.  We need a model of development and consensus building somewhat like what OpenEHR does for archetypes, allowing for quicker development and deployment of these sorts of artifacts.  I also think that this is the way some of these templates should be developed in the future. We should develop a model that can be approved through a general call for consensus, and then periodically, we can roll up several of these templates into a release which gets a more thorough review through the HL7 ballot process.

This would allow HL7 to be responsive to rapidly developing health issues, without having to make it something that we have to panic about.  Note that foreign travel is relevant only for some cases. There are plenty of other ways to be exposed to disease, including everyday activities like going to school or work, or shopping.  For that you might want to be looking at other information in the patient health record, such as their home address, and workplace and school contacts.  IHE also included entries for those contacts in XPHR.

   -- Keith


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