Clinical Model and Terminology Issues in Guideline Execution

Craig Parker, Harold Solbrig, Stan Huff & Roberto Rocha

as part of the SAGE project

The SAGE project is partially funded by NIST/ATP Cooperative Agreement Number 70NANB1H3049

SAGE Overview

Overview – Guideline Flow

GuidelineCreation Guideline

ImportGuidelineExecution

Create guidelinein terms of CEM

Perform mappings fromCEM to host database

Perform inferencebetween local instanceand CEM instance

Step 1

Step 2

Step 3

CEM = Clinical Expression Model (e.g. HL7 Templates)

A Guideline Example

Example drawn from ICSI Acute MI guideline.

Illustrates where clinical model and terminology actions will take place in the process of guideline development, deployment and execution.

Illustrates issues that may arise.

Creating Guidelines

Creating Guidelines

We want to say what to do if thepatient develops a new holosystolicapical murmur.

Lets represent this murmur usingHL7 template #12345 (ACMEmurmur).

In the vocabulary of this templatewe would say “pansystolic” insteadof “holosystolic”.

Step 1 – Guideline Creation

If the patient has a new holosystolic apical murmur then . . . (from ICSI Acute MI guideline)

The term “new holosystolic apical murmur” needs to be mapped to the CEM.

This could happen because at the time of creation only terms that are expressible in the CEM are available to the authors.More likely a knowledge engineer will have to determine a mapping from a clinicians words to the CEM.

We will leave the “new” part of the term for an exercise at a later time.

Step 1 – Map Guideline to CEM

If the patient has a newholosystolicapicalmurmur then . . .

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“MURMUR"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“PHASE"/> <value V=“Holosystolic"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“Apical"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

CEM (HL7 Template)Guideline

Mapping Guideline to CEM

1) Map clinician’s words into a composite expression based on a reference terminology.

2) Use the resulting composite expression to create the CEM instance.

Map to a Reference Terminology

There are often many ways to say the same thing…

Murmur (finding) C0026806

Heart Problem (disease or syndrome) (C0795691)

Heart Murmur (sign or symptom) (C0018808)

Functional heart murmur (Finding) (C023255)

Heart murmur, functional and undiagnosed (Finding) (C0476259)

Systolic Heart Murmur, NOS (Finding) (C0232257)

Pansystolic murmur (Sign or Symptom) C0232258

Map the Guideline to a Reference Terminology

Mapping Granularity

Pansystolic murmur (Sign or Symptom) C0232258

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <value V=“?????"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <value V=“?????"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

Map the Guideline to a Reference Terminology

Mapping Granularity

Pansystolic murmur (Sign or Symptom) C0232258

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <value V=“?????"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“?????"/> <value V=“?????"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

?Granularity is too coarse

Map the Guideline to a Reference Terminology

Mapping Granularity

Murmur (finding) C026806 has-topography: Heart (Body part) C0018787 has-spatial-location: apical (C0205111) has-temporality: systolic (C00391555) quality: complete (C0205197)

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“C026806"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“Body Location"/> <value V=“C001878"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“temporality"/> <value V=“systolic"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

Sufficient Granularity

Map the Guideline to a Reference Terminology

Reference terminology must have a sound foundation

There still may be more than one way to say the same thing…

Pansystolic murmur (Sign or Symptom) C0232258 Murmur (finding) C026806

has-topography: Apex of heart (C0224811) has-temporality: systolic (C00391555) quality: complete (C0205197)

Map the Guideline to a Reference Terminology

Reference terminology must have a sound foundation

There still may be more than one way to say the same thing…

.. but you have to be able to determine whether they are the same thing.

Pansystolic murmur (Sign or Symptom) C0232258

Murmur (finding) C026806 has-topography: Apex of heart (C0224811) has-temporality: systolic (C00391555) quality: complete (C0205197)

Map the Guideline to a Reference Terminology

Software ToolsText search

Hierarchical and relationship navigation

Composition and decomposition

Map the Guideline to a Reference Terminology

Text search toolsSpelling correction

Mapping words and phrases to (near) synonyms; word stemming

Expanding and contracting acronyms and abbreviations

Multi-language capabilities

Context capabilities (MI = Myocardial Infarction? Mitral Insufficiency?)

NLP (“No family history of degenerative heart failure”)

Map the Guideline to a Reference Terminology

Hierarchy and relationship navigationSubtype navigation (broader and narrower terms)

Relationship traversal (etiology, has_part, …)

Search qualification

Map the Guideline to a Reference Terminology

Composition and DecompositionGreatest common supertype

Least common subtype

Convert to canonical form

Compare composite expressions

Difference composite expressions

Map the Guideline to a Reference Terminology

StandardsHL7 CTS Specification

Specifies basic text search tools

Does NOT cover lexical areas (spelling, acronyms, NLP)

Some relationship traversal

Limited composition/decomposition expressions

CTS Specification is directed at the current needs of HL7 (e.g. messaging).

A broader approach is needed to support guidelines.

Importing Guidelines

Importing GuidelinesThis new guideline uses HL7 template#12345.

We represent murmurs using our murmurtable.

How do we create a mapping?

Database Granularity

The same information can be carried in widely varying structures:

PT# observation

1110112 Heart murmur

PT# Tag Value

1110112 Observation Murmur

1110112 Location Heart

PT# Heart Murmur

1110112 TRUE

PT#

1110112

Table 17: Patients with Heart Murmur

Table Names

Tag/Value Pairs

Column Headings

A code in a table

Database Names

Free text

PT# observation

1110112 “Findings indicate a pronounced apical murmur throughout the entire systolic phase…”

Heart MurmurClinic

Database Granularity

The same information can vary in granularity

Slots must be composed or decomposed in the mapping process.

The database may vary in the amount of detail

Some slots may not have mappings.

Step 2 – Guideline Import

Make mapping from CEM to host database.Database Record: HeartMurmurObservation Type = Mitral Regurgitation Grade = III/VI Location = 5th Intercostal Space . . .

Have to deal with issues of differing slots and differing granularity of slotsStructural decompositionSet up inference hierarchies

Step 2 – Map Database to CEM

HeartMurmurObservation Type = Mitral Regurgitation Grade = III/VI Location = 5th intercostal space …

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“MURMUR"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“PHASE"/> <value V=“Pansystolic"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“5th Intercostal Space"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

CEM (HL7 Template)

Database Instance

When populating the CEMthe type “Mitral Regurgitation”

is mapped to phase “Pansystolic”

Guideline Execution

Guideline Execution

The guideline says that if the patienthas a new apical pansystolic murmurwe should . . .

Looking in my database I find that thepatient has a new murmur at the 5th intercostal space.

Is the 5th intercostal space an apicallocation?

Step 3 – Guideline Execution

Traverse term-to-CEM map (depending on compilation strategy).

Traverse CEM-to-DB map.

Perform “MLM” logic.Do terminology inference.

Guideline Execution

Guidelines use two information sourcesTriggers – new information being entered into the system

Existing data – information already contained within the database

Guideline Execution

Approach is different for each:Triggers

Need to determine whether the new information represents an instance of the guideline triggerAnswer may be “yes”, “no”, or “need more information”

DatabaseNeed to select information that may satisfy guideline criteriaDetail, granularity and logic usually precludes exact selectionHave to maintain a balance between quantity (select * from dx_table where pt=‘1110112’) and complexity (select * from dx_table, … where dx_code in (a,b,c,d,…) or dx_code in (select * from codedTerm where sourceCode=‘a’ and relcode in (1,2,3))

Step 3 - Perform Logic

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“MURMUR"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“PHASE"/> <value V=“Pansystolic"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“Apical"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

Guideline CEM Instance<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“MURMUR"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“PHASE"/> <value V=“Pansystolic"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“5th Intercostal Space"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

Database CEM Instance

Apical LocationApical Location

55thth ICS ICS 66thth ICS ICS ……

…… …………

Inference from Terminology

Apical has-child 5th ICSApical has-child 6th ICSApical has-child …

Database representation of a Semantic Network

Other Execution Questions

Where do we iterate through the database instances?

Database services?

Guideline logic (e.g. Arden or GELLO)?

How are terminology services used?Standard terminology services

Host specific terminology services

Notes on Templates

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“Pansystolic murmur"/></A_Observation_event>

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“MURMUR"/> <AR_Observation_event_component> <type_cd V="COMP"/> <A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“PHASE"/> <value V=“Systolic"/> </A_Observation_event> </AR_Observation_event_component> <AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“Apical"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

<A_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“Systolic Heart MURMUR"/><AR_Observation_event_component> <type_cd V="COMP"/> <AR_Observation_event> <class_cd V="OBS"/> <mood_cd V="EVN"/> <cd V=“LOCATION"/> <value V=“Apical"/> </AR_Observation_event> </AR_Observation_event_component> . . .</A_Observation_event>

Notes on Templates

Need to evolve in tandem with terminologies

Heart Murmur ObservationApical HeartMurmur Observation

– Systolic Apical Heart Murmur Observation

• Holosystolic Apical Heart Murmur Observation

Need to be named, cataloged, cross referenced and formally organized

Notes on Templates

To be portable, templates have to be based on an underlying reference terminology as well

Templates represent clinical statements

Without a thorough understanding of the statements and their hierarchical nature, it quickly becomes virtually impossible to make reasonable guidelines.