Green CDA in the UK

Report
Green CDA Implementation
Robert Worden
Open Mapping Software Ltd
HL7 UK
[email protected]
Benefits of Green CDA
• Comparison at technical level:
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Shallower XML (2x)
Fewer nodes (3x smaller messages)
Meaningful business names
Can be readily understood by clinicians
No Version 3 ‘fixed stuff’
Version 3 knowledge is not required for implementors
Easier to test
• Building Green CDA interfaces to any system is a Vanilla
XML interfacing job
• => Major benefits of cost and timescale
• Fully interoperable with Standard CDA
Green CDA in the UK
• Green CDA has major benefits over full standard CDA:
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Complexity
Learning Curve
Testing
Cost and time
• But Green CDA transforms must be 100% reliable
• Green CDA from Open Mapping Software has autogenerated, reliable transforms
• It has been adopted by NHS for the UK Interoperability
Toolkit (ITK)
• The first Green CDA has been rolled out in ITK
• Other Green CDAs are being developed (Discharge
Summary, Health/Social Care Integration)
• Other XML s can be mapped onto the Green Class Model
Interoperable with Standard CDA
• Transforms [Green => Full] and [Full => Green]
must be 100% reliable
• You need transforms in both directions (e.g. for
round-trip tests)
• Transforms must supply all Version 3 fixed stuff
• Transforms are complex
• Transforms must be automatically generated
from the Green CDA definition
• Any manual steps would cost a lot, introduce
errors, and be infeasible to maintain
Message Simplification – The Process
V3 RMIM
(MIF)
Templated
RMIM
(ECore)
Select
Rename
Annotated
RMIM
(Ecore)
Press
the
Button
Simple
Message
Schema
Skeleton
Simple
Message
Simple-Full
Transforms
(XSLT)
Simple-Full
Mappings
Simple Class
Model
(Ecore)
The NHS Green CDA
• Header information only – so applicable to all
NHS CDA domains
• Many header sections (patient, author*4, data enterer,
informant*2, custodian, recipient, authenticator, participant,
encompassing encounter)
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1500 independent data values
Expansion factor *3 to full CDA
Transforms: 9000 + 5000 lines of XSLT
100% accurate round-trips (Full=> Green => Full)
Developed, tested and published by NHS in 6
weeks elapsed time, 1.3 people.
MDHT- Mapping Tool Bridge
• Consolidated CDA is defined in MDHT
• Definition is an Ecore class model + OCL constraints
• Open Mapping tools can read this class model into a
form suitable for defining Green CDAs
• The Green CDA is defined by selecting and renaming
attributes and associations
• Green  full CDA transforms are generated
automatically
• It all works
• This approach is being evaluated for the Transition of
Care Reference Implementation
The Real Power of Green CDA
• The Green CDA class model is much simpler than the RIMbased CDA model
• It is a very suitable target for mapping any other XML to.
• Any =>Any transforms can be generated from the mappings
Simplified
Green ToC
CDA
Full ToC
CDA
Green ToC
CDA Class
Model
Clinical
Informatio
nModel
EHR
database
NCPDP
CCR
Should Green CDA go on the Wire?
• If there is more than one Green CDA definition, is
it safe?
• If each Green CDA instance carries the URL of its
Green => Full transform, it is safe.
• Recipient must check the URL, to see if it is ‘his’
kind of Green CDA.
• If not, he applies the transform to get full CDA;
then his own transform, to get his own Green
CDA
• This is a fully Green CDA ecology
• It is backed by the semantics of full CDA ( = the
reserve currency)
Download the tools
http://www.openmapsw.com/downloads/downloads.htm

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