Case Study: HL7 Conformance in VA Imaging Mike Henderson Principal Consultant Eastern Informatics, Inc.

HL7 Conformance in VA Imaging2 Topics  Introduction: the VA healthcare enterprise  Why use standard interfaces?  Healthcare standards and conformance efforts  Using standards for PACS in VA  Documenting receiver behaviors  Testing commercial system readiness  Conclusion

HL7 Conformance in VA Imaging3 Introduction: the VA healthcare enterprise  VA’s open-source information system: VistA  Imaging module in use since 1990  >1B images captured into VA patient records

HL7 Conformance in VA Imaging4 Introduction: the VA healthcare enterprise  Uses of VistA Imaging Improving quality of care Implementing care plans Example of successful open-systems integration

HL7 Conformance in VA Imaging5 Introduction: the VA healthcare enterprise  Imaging architecture Acquisition by commercial devices (“modalities”) Viewing and storage  VistA is archive of record  Commercial PACS sometimes used for storage and management

HL7 Conformance in VA Imaging6 Why use standard interfaces?  DICOM Image acquisition and formatting for storage System availability and interoperability  HL7 Patient and order information Administrative information Interpretation

HL7 Conformance in VA Imaging7 Why use standard interfaces?  Interoperability facilitation Syntactic  Achievable largely through off-the-shelf standards Semantic  Requires standards integration  Requires constraint framework

HL7 Conformance in VA Imaging8 Healthcare standards and conformance efforts  DICOM  HL7

HL7 Conformance in VA Imaging9 Healthcare standards and conformance efforts  DICOM Standard under development since early 1980s Conformance introduced in V3 in 1993  Handshaking  Data exchange  Exception processing Artifact: Conformance Statement

HL7 Conformance in VA Imaging10 Healthcare standards and conformance efforts  DICOM Conformance Statement contents  Service classes  Information objects  Communication protocols  Storage profiles Intent: document implementation constraints and limitations

HL7 Conformance in VA Imaging11 Healthcare standards and conformance efforts  DICOM Major conformance revisions in  More information  Enforceable template  Real-world examples  Executive summary Embraced, informed and required by VA

HL7 Conformance in VA Imaging12 Healthcare standards and conformance efforts  HL7 V2 conformance development  Andover Working Group  HL7 Conformance SIG: 1997 Gradual expansion of scope to RIM, V3, etc.

HL7 Conformance in VA Imaging13 Healthcare standards and conformance efforts  HL7 V2.5 messaging standard: Chapter 2  Section 2.12: “Conformance”  Profile: definitions and use case  Conformance claim V2.6: Chapter 2B

HL7 Conformance in VA Imaging14 Healthcare standards and conformance efforts  IHE Joint effort by RSNA and HIMSS 1999: Radiology TF profiles  Scheduled Workflow (SWF)  Patient Information Reconciliation (PIR)  Simple Image and Numeric Reporting (SINR)  Others

HL7 Conformance in VA Imaging15 Healthcare standards and conformance efforts  IHE Additional domains  Cardiology  Laboratory  Eye Care  IT Infrastructure Not fully constraining Documents requirements for multiple actors 2005: Radiology users handbook

HL7 Conformance in VA Imaging16 Healthcare standards and conformance efforts  HL7 conformance and IHE compared HL7 conformance  Can be fully constraining  Uses a single messaging standard IHE  Only partially constraining  Uses multiple standards

HL7 Conformance in VA Imaging17 Healthcare standards and conformance efforts  IHE profile artifacts Profile description, actors, process flows Individual transactions  Scope  Use case roles  Referenced standards  Interaction diagram  Transaction detail  Expected receiver behaviors

HL7 Conformance in VA Imaging18 Healthcare standards and conformance efforts  HL7 conformance artifacts Use case model Dynamic definition  Interaction profile  Acknowledgment conditions Static definitions  Message level  Segment level  Field level Now used in HL7-based IHE profiles, e.g., Laboratory

HL7 Conformance in VA Imaging19 Using standards for PACS in VA  Participations DICOM HL7 IHE  Expectations Compliance with industry standards Adherance to IHE guidelines

HL7 Conformance in VA Imaging20 Using standards for PACS in VA  Objectives of commercial PACS integration Expand range of image management options Mitigate risks to patient safety  Misidentification of patients  Misidentification of studies and images  Misassociation of studies/images with patients

HL7 Conformance in VA Imaging21 Using standards for PACS in VA  Profiles for HL7 Messages from Vista to Commercial PACS HL7 message content System behavior Published on Web Complementary DICOM document under development

HL7 Conformance in VA Imaging22 Using standards for PACS in VA HL7 ADT messages used  A01 (admit/visit notification)  A02 (transfer a patient)  A03 (discharge/end visit)  A04 (register a patient)  A08 (update patient information)  A11 (cancel admit/visit notification)  A12 (cancel transfer)  A13 (cancel discharge)  A40 (merge patient – patient identifier list)

HL7 Conformance in VA Imaging23 Using standards for PACS in VA HL7 order and report messages used  ORM (general order message) Trigger event O01 Order control codes  NW (new order/service)  CA (cancel order/service request)  XO (change order/service request)  ORU (observation result unsolicited) Trigger event R01

HL7 Conformance in VA Imaging24 Documenting receiver behaviors  General guidelines  Interface behaviors  Application behaviors

HL7 Conformance in VA Imaging25 Documenting receiver behaviors  General guidelines for PACS All order data, must be stored including VistA study instance UID Patient demo data must be updated as appropriate At least the most recent report must be stored (but it’s OK to store all reports) Application ACKs including ERR segment must be used

HL7 Conformance in VA Imaging26 Documenting receiver behaviors  Interface behavior Use case Dynamic profile  Interaction model  Acknowledgments Static model  Message level  Segment level  Field level

HL7 Conformance in VA Imaging27 Documenting receiver behaviors  Basic data sets Mappings as specified in IHE [Radiology] TF, App. B Patients, visits, orders, reports  Extensions to application behavior Secondary key validation Storage and use of study instance UID  Transmission of exception information

HL7 Conformance in VA Imaging28 Testing commercial system readiness  Profile and testing summary document provided on VA website  Tests for both normal and exceptional conditions  tests performed  Results sent to vendors Variance Categories 1, 2, 3

HL7 Conformance in VA Imaging29 Conclusions  Profiles are the primary tool for communicating interface specifications  HL7 Conformance allows for complete, testable, and verifiable specifications  Profiles are one of several templates used for reproducible interface development documents and processes

HL7 Conformance in VA Imaging30 For more information   

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