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 Guideline Creation Guideline Import Guideline Execution Create guideline in terms of CEM Perform mappings from CEM to host database Perform inference between local instance and 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

We want to say what to do if the patient develops a new holosystolic apical murmur. Lets represent this murmur using HL7 template #12345 (ACME murmur). In the vocabulary of this template we would say pansystolic instead of 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 new holosystolic apical murmur then CEM (HL7 Template) Guideline

Mapping Guideline to CEM 1) Map clinicians 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) C Heart Problem (disease or syndrome) (C ) Heart Murmur (sign or symptom) (C ) Functional heart murmur (Finding) (C023255) Heart murmur, functional and undiagnosed (Finding) (C ) Systolic Heart Murmur, NOS (Finding) (C ) Pansystolic murmur (Sign or Symptom) C

Map the Guideline to a Reference Terminology Mapping Granularity Pansystolic murmur (Sign or Symptom) C

Map the Guideline to a Reference Terminology Mapping Granularity Pansystolic murmur (Sign or Symptom) C ? Granularity is too coarse

Map the Guideline to a Reference Terminology Mapping Granularity Murmur (finding) C has-topography: Heart (Body part) C has-spatial-location: apical (C ) has-temporality: systolic (C ) quality: complete (C )... 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) C Murmur (finding) C has-topography: Apex of heart (C ) has-temporality: systolic (C ) quality: complete (C )

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) C Murmur (finding) C has-topography: Apex of heart (C ) has-temporality: systolic (C ) quality: complete (C )

Map the Guideline to a Reference Terminology Software Tools Text search Hierarchical and relationship navigation Composition and decomposition

Map the Guideline to a Reference Terminology Text search tools Spelling 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 navigation Subtype navigation (broader and narrower terms) Relationship traversal (etiology, has_part, …) Search qualification

Map the Guideline to a Reference Terminology Composition and Decomposition Greatest common supertype Least common subtype Convert to canonical form Compare composite expressions Difference composite expressions

Map the Guideline to a Reference Terminology Standards HL7 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

This new guideline uses HL7 template # We represent murmurs using our murmur table. How do we create a mapping?

Database Granularity The same information can be carried in widely varying structures: PT#observation Heart murmur PT#TagValue ObservationMurmur LocationHeart PT#Heart Murmur TRUE PT# Table 17: Patients with Heart Murmur Table Names Tag/Value Pairs Column Headings A code in a table Database Names Free text PT#observation Findings indicate a pronounced apical murmur throughout the entire systolic phase… Heart Murmur Clinic

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 = 5 th Intercostal Space... Have to deal with issues of differing slots and differing granularity of slots Structural decomposition Set up inference hierarchies

Step 2 – Map Database to CEM HeartMurmurObservation Type = Mitral Regurgitation Grade = III/VI Location = 5 th intercostal space …... CEM (HL7 Template) Database Instance When populating the CEM the type Mitral Regurgitation is mapped to phase Pansystolic

Guideline Execution

The guideline says that if the patient has a new apical pansystolic murmur we should... Looking in my database I find that the patient has a new murmur at the 5 th intercostal space. Is the 5 th intercostal space an apical location?

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 sources Triggers – 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 trigger Answer may be yes, no, or need more information Database Need to select information that may satisfy guideline criteria Detail, granularity and logic usually precludes exact selection Have to maintain a balance between quantity (select * from dx_table where pt= ) 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... Guideline CEM Instance... Database CEM Instance

Apical Location 5 th ICS 6 th ICS … … … … Inference from Terminology

Apicalhas-child5 th ICS Apical has-child6 th ICS Apical has-child… Database representation of a Semantic Network

Drugs Antibiotics Analgesics Cardiovascular Penicillins Aminoglycosides Cephalosporins MethicillinAmoxicillin Nafcillin A more complete example using drugs

Drugshas-childAntibiotics Drugshas-childAnalgesics Drugshas-childCardiovascular Antibioticshas-childPenicillins Antibioticshas-childCephalosporins Antibioticshas-childAminoglycosides Penicillinshas-childPen VK Penicillinshas-childAmoxicillin Penicillinshas-childNafcillin Drugshas-memberAntibiotics Drugshas-memberPenicillins Drugshas-memberPen VK Drugshas-memberAmoxicillin Drugshas-memberNafcillin Drug 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......

Notes on Templates Need to evolve in tandem with terminologies Heart Murmur Observation Apical 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.