1. Archetypes in HL7 2.x Snomed-CT “Computable Medical Records” Andrew McIntyre Medical-Objects http://www.medical-objects.com.au/ NEHTA Snomed-CT Workshop

2. Terminology is for Computers Humans understand text pretty well Computers are pretty hopeless at it –Much better with codes –Can manage much more in memory –Are obsessive and tireless –A path to decision support –Snomed-CT is for computers

3. Focus Concept

4. Attributes = Post Co-Ordination Attributes are defined by model –Vary depending on type of statement –Qualify concepts

5. Context of Statements Past History Family History Planned Possible etc Every statement needs context –Default context Known present About patient Current or specified

6. Context added to statements Removes much ambiguity

7. Context Example Procedure Context These are “Values”

8. Snomed –CT Abstract logical Model under development –Conflicts/overlaps with some HL7 V3 structures HL7 V2 has administrative models –Limited clinical model (Medication mainly)‏ It is possible to represent Snomed-CT Abstract Logical Model in HL7 V2 Requires tree structures within groups of OBX segments – Archetyped HL7 V2

9. Snomed Model Nested Name=Value pairs

10. In HL7 V2.3.1 OBX segments are designed to carry NAME=VALUE pairs with date Dotted Sub-ID for structure Relatively simple display rules –linear display is possible

11. Archetypes in V2 Very Compact representation OBX Sub-ID used for structure Only value nodes need to be included Works with existing display logic Requires CE support! Full semantic transfer SNOMED-CT Abstract model transmitted Requires knowledge of archetype

12. Multiple Inheritance Model Eg Cholecystectomy

13. Multiple Inheritance

14. Gello Statement

15. Requires Patient Model

16. Expressing Snomed-CT Model Snomed Grammar Fully supported by GELLO

17. Gello Can Exploit This

18. Gello can validate Need to ensure statements are valid wrt Model

19. GELLO equivalence

20. Snomed Constraints Archetype base Constraints restricts user to correct terms

21. Constraint Specification

22. MO Terminology Server Uses HL7 V2 or SOAP interface Lookup support with constraints Canonical form support Can run locally or remotely (transparent)‏ SOA architecture GELLO integration Caches frequently used queries locally Available now via Communications clients

23. Summary Snomed-CT allows high level computability Must follow Snomed-CT Model Needs more structure –Archetypes in HL7 V2 can do this –Archetypes can constraint choices Gello, vEMR and Terminology Server allow computable medical Records Standards urgently needed for interoperability of records

24. Resources GELLO and GLIF demo available www.medical-objects.com.au