Green CDA Implementation

1. Green CDA Implementation Robert Worden Open Mapping Software Ltd HL7 UK robert@OpenMapSW.com

2. Benefits of Green CDA • Comparison at technical level: • 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

3. Green CDA in the UK • Green CDA has major benefits over full standard CDA: • Complexity • Learning Curve • Testing • Cost and time • But Green CDA transforms must be 100% reliable • Green CDA from Open Mapping Software has auto-generated, 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

4. 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

5. Message Simplification – The Process V3 RMIM (MIF) Templated RMIM (ECore) Select Annotated RMIM (Ecore) Rename Press the Button Simple Message Schema Skeleton Simple Message Simple-Full Transforms (XSLT) Simple-Full Mappings Simple Class Model (Ecore)

6. 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) • 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.

7. 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

8. The Real Power of Green CDA • The Green CDA class model is much simpler than the RIM-based CDA model • It is a very suitable target for mapping any other XML to. • Any =>Any transforms can be generated from the mappings Full ToC CDA Simplified Green ToC CDA Green ToC CDA Class Model Clinical InformationModel NCPDP EHR database CCR

9. 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)

10. Download the tools http://www.openmapsw.com/downloads/downloads.htm