Snomed-Gello-HL7
More than a pick List
Andrew McIntyre
Medical-Objects
http://www.medical-objects.com.au/
11th HL7 Australia Conference, 13th December 2006
Melbourne, Australia
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
Focus Concept
Attributes = Post Co-Ordination
• Attributes are defined by model
– Vary depending on type of statement
– Qualify concepts
Context of Statements
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Past History
Family History
Planned
Possible etc
Every statement needs context
– Default context
• Known present
• About patient
• Current or specified
Context added to statements
• Removes much ambiguity
Context Example
• Procedure Context
• These are “Values”
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
Some detail
• Nested Name=Value pairs
– Consistent with Snomed-CT Model
– HL7 V2.x can encode this
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
Snomed-CT Model
• Snomed Grammar
Multiple Inheritance Model
• Eg Cholecystectomy
Gello Statement
Requires Patient Model
Gello Can Exploit This
Gello can validate
Need to ensure statements are valid wrt Model
Snomed Constraints
Archetype base Constraints
restricts user to correct terms
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 needed for interoperability of
records