Introduction to Green CDA
CDA Forum, 17th January 2013
Robert Worden
rpworden@me.com
Outline: 30 Minutes + Questions
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What is Green CDA? How do you use it?
Origins of Green CDA
Green CDA Example - PHMR
Questions (1)
CDA Implementation Routes Compared
Green CDA in ITK and ISCF
Questions (2)
Additional Topics
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What is Green CDA?
How do you use it?
• Green CDA is a way of interfacing applications to standard
CDA
• It consists of:
– An intermediate XML structure which is much simpler than full
CDA (this structure is called Green CDA XML)
– Supplied transforms, to convert the simple XML to full CDA, or
full CDA to the simple XML
• Transforms depend on templates
• Interface your application to the simple XML; then use the
supplied transforms to read or write full CDA.
• Get ITK accreditation for the full CDA
• Short-cuts the technical complexity of CDA
• Avoids a long CDA learning curve
Green CDA XML is Simpler than
Standard CDA XML
Fragment of full CDA:
<custodian typeCode="CST">
<npfitlc:contentId extension="COCD_TP145018UK03#AssignedCustodian" root="2.16.840.1.113883.2.1.3.2.4.18.16" >
<assignedCustodian classCode="ASSIGNED">
<templateId extension="COCD_TP145018UK03#AssignedCustodian" root="2.16.840.1.113883.2.1.3.2.4.18.2"/>
<representedCustodianOrganization classCode="ORG" determinerCode="INSTANCE">
<templateId extension="COCD_TP145018UK03#representedCustodianOrganization"
root="2.16.840.1.113883.2.1.3.2.4.18.2"/>
<id extension="RYX" root="2.16.840.1.113883.2.1.3.2.4.19.2"/>
<name>Central London Community Healthcare Trust</name>
</representedCustodianOrganization>
</assignedCustodian>
</custodian>
Corresponding fragment of Green CDA:
<documentOwner id="RYX">
<name>Central London Community Healthcare Trust</name>
</documentOwner>
How to use Green CDA
Application
A
Green
CDA
Simple-toFull
Transform
Full CDA
Full-toSimple
Transform
Green
CDA
Application
B
Full CDA
Application
C
• Reliable transforms to full CDA are supplied; (but may need to be extended for your
application requirements, commercially or using Open Source tools)
• Transforms can be deployed as XSLT (licenced), or as a Java runtime engine (Open Source)
• You only need to interface applications to Green CDA
• This is a simple ‘vanilla XML’ interfacing job
History of Green CDA
• Experiments with ‘simplified XML ITS’ in UK (2006) – automated
transforms to full XML ITS; not taken up by HL7 International.
• ‘Green CDA’ implementation technique proposed by HL7 Structured Docs
Working Group (2010):
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Transforms only go one way: Green => full CDA
Transforms written by hand or low-level mapping tools (so unreliable)
SDWG published the method only, few transforms
See HL7 wiki for current status
• Promoted by HL7 International as an implementation method (CCD vs CCR
for Meaningful Use?)
• Development of Green CDAs for ITK with reliable, automated, two-way
transforms – UK (2011).
Example Green CDA – ITK PHMR
• Personal Health Monitoring Report – for telehealth devices in the home
• DHID published CDA definition in summer 2012
• Green CDA version developed shortly afterwards; now in use on one ISCF
project
• Templates included so far:
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Header templates (Patient, etc.)
Device definitions
Blood pressure series
Blood glucose series
Oxygen saturation series
Pulse Rate series
Thresholds and target values for these observations
• Other templates can be easily included
• Full round-trip transforms, 100% accurate (demo)
• Full PHMR passes ITK CDA checker (demo)
Green-Full CDA Transforms: Autogenerated and 100% Reliable
Green
to Full
Xform
Green CDA
Full ITK CDA
Full to
Green
Xform
• The round trip (full=>green=> full) is 100% accurate
• Easily and automatically testable
• Implemented in Java or XSLT
Questions (1)
Offline questions to
mailto:CFH.interoperabilityteam@nhs.net
Green CDA v. Other CDA Implementation
Routes – Buyer’s Guide
Criterion
Modelbased
Examplebased
Green CDA CDA API
Technical
simplicity
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Templates
covered
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Extensible
within
templates
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Deployment
flexibility
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Dependence
on others
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Use as CDA
receiver
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(Three stars good, one star bad)
ITK Green CDAs Available
• There are Green versions of the following ITK CDAs:
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Non-Coded Document
Discharge Summary
Section 2 / Section 5 Discharge (actually V3)
CAF (for HSCI)
PHMR (telehealth)
• These can pass the ITK CDA checker and TKW now
• Extra templates are easily added
• Extensions for further application requirements are
commercially available, or can be built with Open
Source tools
• XSLT transforms licensed commercially
Green CDA in ISCF
The following projects in the Information Sharing Challenge Fund
are using Green CDA to implement ITK CDA:
Trust
CDA Application Summary
Worcestershire Health
& Care NHS Trust
Health and Social Care Integration; Non-coded document
sharing demographic data and CPA (containing CPA assessment)
assessments
South Devon
Healthcare NHS
Foundation Trust
Use of discharge letters for Out of
Hours care; stored in XDS (IHE)
repository
Central London
Telehealth monitoring and alerts
Community Healthcare for COPD
NHS Trust
CDA in use
Non-coded document
(containing discharge letter)
PHMR ( Oxygen Saturation &
Pulse Rate)
Questions (2)
Offline questions to
mailto:CFH.interoperabilityteam@nhs.net
Speaker contact details:
rpworden@me.com
Additional Topics
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CDA Rendered Text Entries – how do you handle them?
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Investigate the requirement very carefully
ITK-supplied transforms render header data
Some text is free-standing, not related to coded entries
Additional hand-coded transforms can generate HTML tables from coded entries
Mapping and transforming CDA to other XML, V2, etc.
– Making mappings is quicker than writing interface code
– Generates translations to CDA in both directions
– Open Source tools available (Eclipse based)
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Generated Java CDA API
– Simple classes and getter/setter methods for Green CDA fields
– API can read or write full CDA
– Open Source tools available (Eclipse)
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CDA Editor/Viewer
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Green CDA fields are just those a clinician may need to edit
Web-based, automatically generated editor
Configurable user interface
Outputs or reads full CDA
Open Source tools available (Eclipse)