1. Clinical Document Architecture

2. Outline History Introduction Levels Level One Structures

3. History 1996  Kona Architecture 1998  Patient Record Architecture 2000  ANSI/HL7 CDA R1.0

4. Scope The scope of the CDA is –standardization of clinical documents for exchange CDA enables, but does not constrain: –authoring –document management –storage –display

5. Differences to other standards Others focus on EHR CDA focuses on document for exchange Other abstract the architecture as directory structure CDA abstracts the architecture as document structures

6. CDA Implementations PICNIC (EU) SCIPHOX (Germany) WebOnColl (Greece) NHS South Staffordshire (United Kingdom)

7. What is a document? CDA documents are not birth-to- death aggregate records CDA documents are defined and complete information object that can exists outside of a message and can include text, images, sounds and other multimedia content

8. CDA Documents Level One consists of three technical specifications –CDA Header –CDA Body –HL7 Datatypes

9. CDA Levels This specification defines a multi level architecture where each level is derived from a more basic level levels refer to varying degrees of required markup granularity and specificity does not refer to the depth or granularity of the content

10. CDA Levels Level One specify one core DTD At level 2 and 3, DTDs differ for different document types –History Summary –Physical Summary –Discharge Summary Cardiology Discharge Summary Respirology Discharge Summary the classification has not been defined There is only one DTD for level one

11. CDA Levels Levels provide iteratively adding greater markup to clinical documents Levels establish baselines for conformance

12. CDA Levels & RIM Semantics Levels are distinguished by: –markup granularity –RIM-derived markup Level One: RIM-derived document header. Body is largely structural, although codes can be inserted. Level Two: HL7 Templates can constrain the general Level One DTD, resulting in Level Two DTDs. Level Three: Clinical content can be marked up to the extent that it is modeled in the RIM.

13. Level 1 (Coded Header) good for largely narrative clinical notes

14. Level 1 Only header includes semantics There is no semantic in level one body Level one compliance offers interoperability for human-readable content Header is derived from RIM

15. Level 2 templates layered on top of CDA Level One. These templates constrain the CDA Level One tags, without introducing any new markup

16. HL7 Templates created by domain experts, like archetypes A template is a structured collection of data, aggregated for some purpose, of interest to one or more healthcare stakeholders constrained at abstract level and at the level of syntax What is a “constraint”? – called “ROS” must contain on “vital signs” – called “H&P” must contain called “ROS”

17. Level 2 (Coded Structure) Domain specializations or differences starts at this level It contains the same coded header as Level 1

18. Level 3 adds additional RIM-derived markup to the CDA Level One specification, enabling clinical content to be formally expressed to the extent that is it modeled in the RIM.

19. Level 3 (Coded Content) in Level 3 full document semantics for arbitrary machine processing is required specificity should be consistent with the RIM and be consistent with the coded header and coded structures of Level 1 and 2 The aim is to meet the machine processing requirement

20. Level 3 Body Example

21. CDA Levels CDA Levels are distinguished by the degree of granularity of the markup Clinical content remains constant

22. Levels

23. Relationship to HL7 messages CDA complements HL7 messaging specs A CDA document is a defined and complete information object that can exist outside of a messaging context A CDA document can be a MIME encoded payload within an HL7 message

24. Relationship to HL7 messages CDA documents are encapsulated as MIME packages within HL7 messages exchanged in any event/message that exchange documents

25. CDA & Document Management (Chapter 9) Chapter 9 messages can be useful in sending CDA documents between document management systems

26. Local Document Management System Local DMS can utilize CDA to exchange documents

27. Outline Level One: –HL7 Datatypes –CDA Level One Header –CDA Level One Body

28. HL7 datatypes specification that attempts to define all data types needed for healthcare information exchange provide semantic constraints for the attributes of the RIM classes Datatypes are defined for: –character strings and display data –codes and identifiers –quantities Coded CDA components or elements have the two- letter ending “cd” (SNOMED)

29. HL7 datatypes Every vocabulary has a unique HL7 assigned identifier The root object identifier –2.16.840.1.113883 ICD10 –2.16.840.1.113883.6.3

30. The CDA Header - Purpose The CDA Header is constant across all CDA documents (levels). Its purpose is to: –Enable clinical document exchange across and within institutions –Facilitate clinical document management –Facilitate compilation of an individual patient’s clinical documents into a lifetime electronic patient record (“uniquely identify a single patient”)

31. CDA Header There are four logical components of the CDA Header: – Document information – Encounter data – Service actors (such as providers) – Service targets (such as patients)

32. CDA Level One Header DTD - Example

33. CDA Header DTD

34. CDA Header Instance (Patient Part)

35. CDA Instance

37. CDA Header: local_header Local Header Markup: <status_cd V=“Final” S=“OID value” DN=“Legally Attested”/>

38. CDA Level One Body The body consists of either –nested containers (sections, paragraph, lists, tables) –non-xml blob (Encapsulated Data) The body may be coded

39. Level One Body Example

40. CDA Body

41. Section The same purpose as in the usual documents A container used to wrap other containers (“folder” in CEN) has: –optional caption –nested section or structure elements –optional coded_entry elements

42. CDA Level One Body Structures –Paragraphs –Lists –Items –Tables Entries –Character Data (#PCDATA) –Content –Links –Coded Entries –Observation Media –Localization

43. Body structures: paragraph Can occur in section, item and table cells

44. caption element The same purpose as in the usual documents A label for a container Occurs in section, paragraph, list, item and table Contains text and links and can be coded using caption_cd represents context of a container but do not have to

45. Body entries: content Occurs in local_markup, table cells, paragraph, item and nested within content Contains zero or more other entries (that is, like containers for entries)

46. Body entries: character data #PCDATA Occurs in content, local_markup, caption, link_html or table cells

47. Body entries: coded_entry Inserts codes from HL7 recognized coding schemes or locally defined codes into document uses concept descriptor (CD) data type Can occur in section and content

48. Body: content & coded entry

49. Local Markup CDA seeks to standardize the highest level of shared meaning while providing a clean and standard mechanism for expressing meaning that is not shared transform local tag set into CDA tag set and where there is no equivalent use “local_markup”

50. CDA Body Localization: local_markup Can occur in coded_entry, observation_media, content, table cells Contains zero or more entries Value can be drawn from local vocabulary domain