Contemporary Informatics Tools - Health Informatics in the Cloud - page 36

Fig. 3.5 Simple Human Readable Display of Part of a Continuity of Care Document (CCD)
that is both human-readable 10 and machine-readable. Its key tool is tags with stan-
dard names that tell the computer what data they enclose. We'll see an example of
these tags in a moment. Fig. 3.5 is a very simple example of how an XML document
might be visualized for a human to read. It is taken from a CCD posted on the
Internet by Dr. John Halamka, the CIO of a leading Boston hospital. [ 23 ] I recom-
mend his blog, Life as a Healthcare CIO . [ 24 ]
So CDA specifies the structure of the documents, but what about their contents?
A number of key documents have been defined by the Healthcare Information
Technology Standards Panel (HITSP). They are the C28 - Emergency Care Summary
Document, C32 - Summary Documents Using CCD, C35 - Lab Result Terminology,
C38 - Patient Level Quality Data Document, C72 - Immunization Message and the
C78 - Immunization Document. More globally the modules that might be used in
any of these documents comprise the C83 CDA Content Modules standard. [ 25 ] For
our purposes it is only necessary to know that these standards go into an incredible
amount of detail.
For now let's focus on the key CDA document for care coordination, the CCD.
You can think of it as a digital version of the cover sheet or clinical summary typical
of paper charts. It would likely contain the patient's key demographic data, problem
list, medications, allergies, laboratory results and so on. As opposed to a paper ver-
sion, this data is both digital, so a computer can read it, and it is “tagged” using
XML so a computer knows what each item of data is. A CCD can be quite complex
but the basic concept is easy to understand.
On the following page I provide part of the vital signs from the XML taken from
a sample CCD posted by the HIMSS Electronic Health Record Association. [ 26 ] 11
I've highlighted three codes that are important to computer interpretation of what
follows. The fi rst:
<templateId root=”2.16.840.1.113883.10.20.1.16”/>
tells the computer what template to use for this information. A template basically
defines the sections that should be present. The second:
10 However, a human would not want to sit down and read an XML document as one would read a
topic. The problem of visualizing the information in an XML document most usefully for humans
is still an area of active research and development.
1 1 The technically inclined might go to reference 26 and click the Download the CCD QSG (Quick
Start Guide) link. It provides two full CCD examples and a guide to study.