Cross-Paradigm Interoperability Implementation Guide for Immunizations

Cross-Paradigm Interoperability Implementation Guide for Immunizations

HL7 Service Oriented Architecture (SOA) Workgroup

Version 1.10

DecemberJuly, 2012

Authors

Bud Farnham, Software Partners LLC

Steve Hufnagel, The Information Applications Group (TIAG)

Alean Kirnak, Software Partners LLC

Stefano Lotti, Invitalia

Ann Wrightson, NHS Wales

Contents

Authors 2

Introduction 5

Current Results 5

Methodology 5

Approach 8

Project Need 8

Project Organization 8

Organizations and Artifacts 8

Layered Service Architecture 12

Overview 12

Introduction to SAIF 15

The Interoperability Specification Matrix for X Paradigm 16

Logical Progression 19

Use Cases 21

Overview 21

Analysis 21

Mapping to Service Stack 23

Gaps 23

Graph 23

Remaining Work 23

Case Studies 24

Platform Independent Model 25

Common Information Model 25

Approach 25

Unraveling the ‘cascade of templates’ between standards 25

Immunization Content and Consolidated CDA 28

IHE PCC Technical Framework Supplement, Immunization Content 28

Field mappings between HL7 V2.x, IHE IC, and HL7 CDA/CCD 29

Mapping to Service Stack 30

Common Behavior Model 32

Solution Architecture 33

Service architecture design 33

Relating to SAIF 35

Proposal for Xparadigm TOC 35

Random Notes on Work that Remains 37

Appendix A: A Brief Tutorial on CDA-Related Technologies 38

Reviewed HL7 V2.x Messaging Standard 40

Reviewed HL7 V3 Standard 40

Reviewed IHE Technical Framework 42

Software Implementations of CDA- Brief Overview 43

CDA implementation using XML techniques 43

Model driven CDA implementation 43

XML and Model Driven Approaches Compared 44

Using NIST Schematron to validate IC documents. 45

References 45

Documents Searched 45

Schemas Searched 46

Sample XML Documents 46

NIST Schematron 46

List of Acronyms 47

Future Appendices 48

Revision History 49

Authors 2

Introduction 5

Current Results 5

Methodology 5

Approach 8

Project Need 8

Project Organization 8

Organizations and Artefacts 8

Layered Service Architecture 12

Overview 12

Introduction to SAIF 15

The Interoperability Specification Matrix for X Paradigm 16

Logical Progression 19

Use Cases 21

Overview 21

Analysis 21

Mapping to Service Stack 23

Gaps 23

Graph 23

Remaining Work 23

Case Studies 24

Platform Independent Model 25

Common Information Model 25

Approach 25

Unraveling the ‘cascade of templates’ between standards 25

Immunization Content and Consolidated CDA 28

IHE PCC Technical Framework Supplement, Immunization Content 28

Field mappings between HL7 V2.x, IHE IC, and HL7 CDA/CCD 29

Mapping to Service Stack 30

Common Behaviour Model 32

Solution Architecture 33

Service architecture design 33

Relating to SAIF 35

Proposal for Xparadigm TOC 35

Random Notes on Work that Remains 37

Appendix A: A Brief Tutorial on CDA-Related Technologies 38

Reviewed HL7 V2.x Messaging Standard 40

Reviewed HL7 V3 Standard 40

Reviewed IHE Technical Framework 42

Software Implementations of CDA- Brief Overview 43

CDA implementation using XML techniques 43

Model driven CDA implementation 43

XML and Model Driven Approaches Compared 44

Using NIST Schematron to validate IC documents. 45

References 45

Documents Searched 45

Schemas Searched 46

Sample XML Documents 46

NIST Schematron 46

Future Appendices 47

Revision History 48

Introduction

The X Paradigm project is meant to provide guidance in creating deployments where many systems, new and legacy, speaking different standard protocols, must interoperate to satisfy one healthcare domain. The immunizations domain was chosen due to its relative simplicity, existing infrastructure, and the background of some authors. The HL7 Service-Aware Interoperability Framework (SAIF) provides the theoretical and standards framework for approaching the project.

This document is an early draft released for HL7 ballot for purposes of collecting broad review and comment. The project is not complete. A next pass is anticipated to incorporate comments and proceed along the lines suggested at the end of each section.

For short, this project will be referred to as “X Paradigm” throughout the remainder of this document.

Current Results

The most immediately useful output of the current document is probably the mappings from HL7 V2 immunization messages to the CDA-based IHE Immunization Content profile and the Consolidated CDA project. Included in that exercise is an explanation of the cascade of templates used by CDA solutions generally.

A second useful output thus far is a sense of direction as to where this project is headed and how one may ultimately implement SAIF. From our starting point, one can see a natural methodology beginning to form: top down from storyboards, and simultaneously, bottom-up in the information perspective. A classic “meet in the middle” results when one begins to notice the traceability from use cases to service specifications to information and behavior. Note that the presence of existing service specifications in our starting set of standards (“artefactsartifacts”) is essential. If they didn’t exist, we would immediately have to generate them.

Finally, the analysis so far has pointed out some notable gaps in the set of currently available standards. There are no standards in any paradigm (messages, documents, and services) that implement access to a centralized inventory management service by a remote system, for example. Such services are currently performed by U.S. immunization registries. As Electronic Health Record (EHR) systems begin to interoperate with registries, this inventory function must either be supplanted by the EHR systems, or a protocol for accessing a central system must be defined.

Methodology

X Paradigm has no clear precedent to guide its methodology. In parallel, the SAIF Implementation Guide is being developed; thus, X Paradigm may inform the latter, and/or may need to be revised based upon the course it takes. X Paradigm represents a domain-specific effort to create a Service-Aware architecture using existing standards and SAIF. At the same time, it is an important project goal to remain tangible; that, by taking the one specific immunization domain, we have an opportunity to “ground” SAIF as something that current users of HL7, OMG, IHE and other standards can paint themselves into.

There is also no clear precedent for working across Standards Development Organizations (SDOs). Issues of membership, intellectual property, process, meeting schedules, and access to artefactsartifacts all must be addressed. Thus far, it has been the effort of individuals such as Richard Soley, Ken Rubin, Laura Bright, Michael Flynn, Noam Arzt and others who have helped us reach out to SDOs and profiling organizations outside of HL7: the Object Management Group (OMG), Integrating the Healthcare Enterprise (IHE), and the American Immunization Registry Association (AIRA).

The project organization so far has been facilitated by a series of conference calls hosted by our sponsoring Workgroup, Service-Oriented Architecture (SOA), and co-sponsoring Workgroup, Public Health and Emergency Response (PHER), and by a project wiki: http://hssp.wikispaces.com/Cross+Paradigm+Interoperability+Implementation+Guide+for+Immunization

Beyond that, our methodology was to simply put the shovel at the spot we thought was likely the closest and start digging. The result so far is what you see in the rest of this document. At this point, the solution trend is toward a tree-like graph with entry points for various storyboards, traversing a specific SOA taxonomy, including Platform Independent Models (information and behavior) and choosing different service Platform Specific Models depending upon which artefactsartifacts are being used by the communicating systems.

Our stated goal was not to create anything new, but to use existing work. In the end, it is likely that something new will in fact be created to provide transformation and translation among existing artefactsartifacts. Most likely this will take the form of new and revised service specifications along the lines of existing Healthcare Service Specification Project (HSSP) service definitions. More information on HSSP can be found at hssp.wikispaces.com.

Approach

Project Need

From the Project Scope Statement (HL7 Project 863Click Here to View Project Details):

Currently, several HL7 and other SDO standards apply to the immunization use case, including messages (HL7 V2 and V3) documents (V3 CDA), and services (IXS, RLUS, DSS, etc.). Some, such as HL7 V2 and V3 messaging, and CDA/CCD models including the IHE Immunization Content profile, are fairly mature. However, the issue of achieving interoperability in an environment of diverse standards remains. A key lesson of Meaningful Use Stage I in the U.S. has been that mismatched sender and receiver capabilities in some localities have inhibited public health reporting objectives. The practical use of SAIF is of interest in European interoperability projects as well, for immunizations and beyond. What is missing is something to tie the various standards together in an interoperable fashion to satisfy the use case.

Project Organization

In determining approach, the X Paradigm project found no clear precedent in HL7. It is meant to create a minimum of new material, instead reaching across Standards Development Organizations (SDOs) to leverage the common elements as well as diversity among existing, immunization-related standards. There was some struggle initially to figure out how to wield this diversity of information and work across groups. We wish to thank Ann Wrightson and Steve Hufnagel for invaluable assistance in conceiving an approach.

This document is divided into the following sections:

I.  Layered Service Architecture

II.  Use Cases

III.  Case Studies

1. US
2. Non-US

IV.  Platform Independent Model

1. Common BehaviourBehavior Model
2. Common Information Model

V.  Solution Architecture

VI.  Relating to SAIF

Organizations and Arteifacts

A first step was to identify which immunization-related standards, or artefactsartifacts, to include within the scope. ArtefactsArtifacts were cross-referenced with the project sections they most closely apply to. Links to source documents, usually on the web site of the SDO organizations responsible for them, were researched and documented. The results appear in the table below. Links appear in a spreadsheet entitled “artefacts.xlsx” attached as part of this ballot package.

Table 1: X Paradigm Organizations, ArtefactsArtifacts and Applicable Project Sections

Work then started in several sections more or less simultaneously; specifically, the Common Information Model subsection of Platform Independent Model and Use Cases; followed closely by Layered Service Architecture. A top down and bottom up approaches were taken simultaneously. The Common Information Model section was approached bottom-up by first cross-referencing the data elements of various artefactsartifacts - HL7 V2 messages, IHE Immunization Content CDA, Consolidated CDA - with an informal, master list of immunization data elements based upon official and proposed future recommendations of the National Vaccine Advisory Council (NVAC). The Use Cases section was approach top-down by analysinganalyzing the collection of storyboards and use cases within the Immunization Domain Analysis Model (Immunization DAM). The result is a "meet in the middle" approach - an approach also elaborated in one of the project artefactsartifacts, “A Service-Oriented Architecture (SOA) View of IHE Profiles” (“IHE SOA White Paper”).

The current ballot materials bring together the various parts into the evolving methodology and conclusions of X Paradigm. At this writing, effort has been focused on certain artefactsartifacts which proved to be the most logical starting points; others are scheduled to be folded in after this initial draft. Where particular artefactsartifacts are treated in a particular project section, a capital "X" appears in the cross-reference in the above table. Small "x" indicates an artefactartifact is scheduled to be incorporated in future phases. In the last section, Relating to SAIF, a rework of the project approach and outline is suggested for the next version.

Layered Service Architecture

Overview

The goal of this section is to develop a layered service architecture that shows how business-level services are supported by generic support services.

X Paradigm focusses upon scoped services specifications from the Healthcare Service Specifications Project (HSSP), plus existing broad paradigms such as HL7 Version 2 and Version 3 messaging and Clinical Document Architecture Release 2 (CDA R2). The scope suggested by the project scope is patient identification, immunization data exchange, decision support (recommendations, adverse reactions, contraindications), and possibly vocabulary-related services.