Integration Profiles and Frameworks

IHE (Integrating the Healthcare Enterprise)

Mission: Improve the way computer systems in healthcare share information Method: Defines integration profiles using existing standards

IHE Domains

Radiology (RAD):

• Scheduled Workflow (SWF)
• Patient Information Reconciliation (PIR)
• Consistent Presentation of Images (CPI)
• Portable Data for Imaging (PDI)

Cardiology (CARD):

• Cardiac Catheterization Workflow (CATH)
• Echocardiography Workflow (ECHO)

Laboratory (LAB):

• Laboratory Testing Workflow (LTW)
• Laboratory Device Automation (LDA)

Pharmacy (PHARM):

• Community Medication Prescription and Dispense (CMPD)

IT Infrastructure (ITI):

• Patient Demographics Query (PDQ)
• Patient Identifier Cross-referencing (PIX)
• Cross-Enterprise Document Sharing (XDS)
• Mobile Access to Health Documents (MHD)

Patient Care Coordination (PCC):

• Query for Existing Data (QED)
• Cross-Enterprise Document Reliable Interchange (XDR)

Key IHE Profiles

XDS (Cross-Enterprise Document Sharing)

Purpose: Share documents across healthcare organizations Architecture: Registry-repository model

Components:

• Document Source: Creates and publishes documents
• Document Repository: Stores documents
• Document Registry: Stores metadata and references
• Document Consumer: Queries and retrieves documents

Transactions:

• ITI-41: Provide and Register Document Set-b
• ITI-18: Registry Stored Query
• ITI-43: Retrieve Document Set

Metadata:

<ExtrinsicObject id="Document01" objectType="urn:uuid:7edca82f-054d-47f2-a032-9b2a5b5186c1">
  <Name>
    <LocalizedString value="Discharge Summary"/>
  </Name>
  <Description>
    <LocalizedString value="Hospital discharge summary for John Doe"/>
  </Description>
  <Slot name="creationTime">
    <ValueList>
      <Value>20231119120000</Value>
    </ValueList>
  </Slot>
  <Slot name="languageCode">
    <ValueList>
      <Value>en-us</Value>
    </ValueList>
  </Slot>
  <Slot name="serviceStartTime">
    <ValueList>
      <Value>20231115</Value>
    </ValueList>
  </Slot>
  <Slot name="serviceStopTime">
    <ValueList>
      <Value>20231119</Value>
    </ValueList>
  </Slot>
  <Classification classifiedObject="Document01"
                  classificationScheme="urn:uuid:93606bcf-9494-43ec-9b4e-a7748d1a838d">
    <Slot name="authorPerson">
      <ValueList>
        <Value>^Provider^Jane^^^MD</Value>
      </ValueList>
    </Slot>
  </Classification>
  <Classification classifiedObject="Document01"
                  classificationScheme="urn:uuid:41a5887f-8865-4c09-adf7-e362475b143a"
                  nodeRepresentation="34133-9">
    <Name>
      <LocalizedString value="Summarization of Episode Note"/>
    </Name>
    <Slot name="codingScheme">
      <ValueList>
        <Value>LOINC</Value>
      </ValueList>
    </Slot>
  </Classification>
  <ExternalIdentifier identificationScheme="urn:uuid:58a6f841-87b3-4a3e-92fd-a8ffeff98427"
                      value="2.16.840.1.113883.19.5^^^&2.16.840.1.113883.19.5&ISO">
    <Name>
      <LocalizedString value="XDSDocumentEntry.patientId"/>
    </Name>
  </ExternalIdentifier>
  <ExternalIdentifier identificationScheme="urn:uuid:2e82c1f6-a085-4c72-9da3-8640a32e42ab"
                      value="1.2.3.4.5.6.7.8.9">
    <Name>
      <LocalizedString value="XDSDocumentEntry.uniqueId"/>
    </Name>
  </ExternalIdentifier>
</ExtrinsicObject>

PIX (Patient Identifier Cross-referencing)

Purpose: Cross-reference patient identifiers across systems Use Case: Patient has different IDs in different systems

Workflow:

1. System A registers patient (ID: A-123)
2. System B registers same patient (ID: B-456)
3. PIX Manager links A-123 to B-456
4. Systems can query PIX to get corresponding IDs

PDQ (Patient Demographics Query)

Purpose: Query patient demographics across systems Typical Use: Registration system queries centralized demographics

XDR (Cross-Enterprise Document Reliable Interchange)

Purpose: Push documents to known recipients Use Case: Hospital pushes discharge summary to primary care physician Similar to: Direct messaging but using IHE profile

MHD (Mobile Access to Health Documents)

Purpose: RESTful access to documents (simplified XDS) Target: Mobile applications Based on: FHIR

IHE Connectathon

Annual Event: Vendors test interoperability Process:

• Implement IHE profiles
• Test with other vendors
• Demonstrate conformance
• Publish integration statements

HL7 Messaging Patterns

Point-to-Point:

System A ----HL7 V2----> System B

Hub-and-Spoke (Interface Engine):

         Interface Engine
         /     |     \
        /      |      \
   Sys A    Sys B    Sys C

Enterprise Service Bus (ESB):

Sys A --\
Sys B ---\
          ESB (Message Bus)
Sys C ---/
Sys D --/

Enterprise Master Patient Index (EMPI)

Purpose: Maintain single view of patient across systems

Functions:

• Matching: Identify duplicate patients
• Linking: Associate records across systems
• Cross-referencing: Provide ID translation
• Demographics: Maintain master demographics

Matching Algorithms:

• Deterministic (exact matches on key fields)
• Probabilistic (weighted scoring)
• Machine learning-based

Challenges:

• Name variations (nicknames, married names)
• Data entry errors
• Missing data
• Similar demographics (family members)