Training Course Title

Experience Implementing SNOMED-CTChris Wroe

• Experience to date

• Term Subsets

• Term Search

• What is being worked on (SNOMED-CT in the data lifecycle

Overview

Data entry

Data storage and messaging

Data analysis

Experience - subsets• SNOMED-CT is a reference terminology –

• large and covers most aspects of medicine

• Any one clinical context requires far fewer terms

• Subsets important

• Content

• Surgical procedure subsets for operating theatre applications

• Diagnosis subsets, Primary care relevant subsets

• Allergies and alerts subsets

• Software

• Need the ability to restrict selection to a particular subset

Anatomy

Procedure

Disorder

Procedures only

Usability of term search

• Aiming for minimal impact on documentation time

• Searching for a term to add to the record must be straightforward and fast

• Balance of brevity, sensitivity and specificity

Key search features•Brevity

•Sensitivity

•Selectivity

•Responsive – users wont have the time to page through multiple pages of results

Unordered start of word search within phrase

Usability of term browsing

• Recording for clinical care should allow term to be recorded at whatever level of detail necessary

• Need for browsing to more general or more specific terms.

• SNOMED-CT hierarchy designed to be machine interpretable

• Need for navigation subsets to apply a recognisable table of contents view onto SNOMED-CT for a specific context

More recognisable

hierarchy

Current work & issues in using SNOMED-CT in the clinical data lifecycle

1: Data entry

Entering a SNOMED-CT term

• Always ask when and for what purpose?

• Supporting interoperability is key

• Several mechanisms to enter from a controlled list of terms

• In primary care a great deal of experience

• In secondary care/ mental health, community health less experience.

• Why general practitioners use computers and hospital doctors do not-Part 1 & 2: T Benson - 2002 , BMJ

What happens when a user cannot find a term? Term triage

• It is there in the subset but user could not find it

• It isn’t in the subset but is in SNOMED-CT

• The concept is in SNOMED-CT but the required synonymous term is not present

• It isn’t in SNOMED-CT but could be expressed using postcoordination

• It isn’t in SNOMED-CT and would need a new concept

End user solution: Up terming

• Up terming. Choose a more general term, flag it as incompletely captured and enter the additional information in free text

• Issues: Hierarchy not supported in all applications

Background solution : New term request

• Report missing term to Cluster/ National/ International level.

• Issues: Life cycle for changes

Solution 3: end user extension

• Allow user to postcoordinate where possible

• Issues: Post coordinated data entry not supported by all applications

SNOMED-CT in forms

Assessment forms

• SNOMED-CT is a reference terminology

• Context can reduce verbosity

• Family history of ischemic heart disease (297242006)

• Interface terminology products often have additional context specific information of the form

• ‘If you picked this symptom these are the likely diagnosis terms you may want to choose from’

Storage

Storage

• Applications often store information

as key/values reflecting the

question & answer on the form

• Model of use

• Were enzymes elevated? = yes

• Model of meaning

• Raised cardiac enzyme or marker

(finding) - 405740000

• Important to have access to both

Storage and messaging with postcoordination

Procedure | Laterality

Oophorectomy |Right

ApplicationOophrectomy (83152002 )

laterality (272741003 )

right (24028007 )

Message out

Right Oophrectomy (302376006 )

Message in

hl

Left Oophorectomy | Right

SNOMED-CT and analysis

Analysis

• Reporting, audit, decision support rules all depend on detecting general cases (asthma) from specific information in records.

• Solutions

• Enumerate all specific terms that are relevant

Stable but time consuming (mild asthma, moderate asthma…)

• Use the SNOMED-CT hierarchyChanges over time (asthma and its descendants)

Analysis and postcoordination

Incisional hernia repair

Repair of hernia of abdominal wall

Is -a

Approach endoscopic approach

Endoscopic procedure

Solution• Either add more report criteria to look for both existing

endoscopic procedures in SNOMED-CT or procedures further qualified with this concept

• Or use specialist software to infer these additional hierarchical relationships.

Conclusion

• Have to keep the whole clinical data lifecycle in mind when implementing SNOMED-CT

• A fair number of work areas upstream and downstream of messaging to get interoperable data