1. openEHR The Reference Model
Thomas Beale
Sam Heard

2. openEHR Semantic architecture
Screen Forms
1:N
Messages
1:N
Reports
Templates
1:N
Terminology
interface
Data conversion
schemas
Terminologies
Archetypes
Snomed CT
ICDx
ICPC
1:N
Querying
What openEHR
provides
Reference Model

3. Specification Map
Archetype Query Language
Terminology Subset Syntax

4. Reference Model – Class model overview

5. The reference model – Structure of one EHR
All versioned

6. Structure of one Composition
ENTRYs –
where the
data are

7. Context Model in openEHR

8. Time in openEHR

9. Time in openEHR

10. Time in openEHR

11. Security Features
Separation

12. Entries – the clinical information

13. Entry types
Archetype Query Language
Terminology Subset Syntax

14. Entry types based on process
Investigator
agents
investigator
This process is cyclic & repetitive
Clinicians don’t always document every step

15. History of Solutions
GeHR Australia – early version of Entry types based on information categories in philosophy + problem-solving

16. History of Solutions – Danish G-EPJ

17. History of Solutions - Samba

18. History of Solutions – Act-based
Includes
RICHE
HL7v3 RIM
Many others
Problems
Everything is an act – good for tracking business process steps, but not natural to physicians
Hard to model typical clinical recordings

19. Our approach – ‘Clinical Investigator’
Based on clinical process
MedInfo 2007
paper

20. Entry types based on process
Investigator
agents
investigator
This process is cyclic & repetitive
Clinicians don’t always document every step

21. Leading to an Ontology ADMIN_ENTRY EVALUATION INSTRUCTION OBSERVATION
ACTION
EVALUATION
INSTRUCTION
ADMIN_ENTRY

22. (with a speculative part for Admin)

24. Specification Map
Archetype Query Language
Terminology Subset Syntax

25. RM data types & structures

26. data_structures

27. data_structures.item_structure

28. item_structure.representation

29. data_structures.history

30. History – Basic Structure

31. History - Variations

32. History – Storing Device Data Efficiently
14,400 x 1 second samples from device
5 x Events in openEHR History

33. Math Functions

34. Glucose Tolerance Test

35. Versioning

36. Specification Map
Archetype Query Language
Terminology Subset Syntax

37. Basis of versioning (similarly to CVS, Subversion etc…)
We use the Composition as the unit of change (like a file in Subversion)
Folder structure also versioned
We use the Contribution as the unit of committal (like a change-set)
Pre-commit check ensures that the current state of Compositions & Folder structure unchanged since check-out

38. Versioning Current Version Family History Current medications Problem
List
Care
Plan
Contact
12/4/2003
Problem
List ++
Contrib
12/4/2003
Test Results
15/4/2003
Contrib
15/4/2003
Contact
20/4/2003
Current
Meds ΔΔ
Care
Plan Δ
Contrib
20/4/2003
Correction
22/4/2003
Contrib
22/4/2003
Current Version

39. Conflicts & Merging – One System
User A
System
User B v1
v1a
v1b
commit v2
commit?
v2a
merge v3
commit

40. Synchronisation Problems
Sys C
Sys A v1 v2 v3
Sys B
Solutions:
designated master repository from which to update
reliable, global version identification scheme v1 v1 v1
Are we getting
Duplicates?
Do we have
the latest?

41. Distributed conflicts
This can only happen:
where no master designated
no update-before-commit
patient presents in both places
i.e. ad hoc situation, e.g. patient
sick while on holiday
Solution:
One of the systems will be the
Patient’s ‘home’ system
Sys C
Sys A v1 v1
v2a
v2c

42. Why is the openEHR RM useful?
Because it was developed with clinical input
OGTT example
It provides a solid ontological basis for the next levels:
Archetypes
Templates
GUI, messages etc