Robert Worden Open Mapping Software Ltd rpworden@me.com FHIR Transform Engine Robert Worden Open Mapping Software Ltd rpworden@me.com

Summary NHS strategy mandates interoperability, and the preferred route uses HL7 FHIR. FHIR is supported by NHS England, providers, and suppliers Hundreds of healthcare applications will need FHIR interfaces, to interoperate This requires two-way transforms between FHIR and local or proprietary APIs Transforms can be developed in one of two ways: In code By a mapping and transform toolkit Mappings have many advantages: Quicker, cheaper to develop Mappings are visible and maintainable Mature test tools The FHIR Transform Engine has the required capability It is easy to adopt and use now: Open Source runtime translator Development tools free to NHS organisations Training and support are available

Transforms by Mappings Eclipse-based mapping toolset Capture automatically the structure you are mapping from (e.g. XML, RDBMS) Capture automatically the FHIR profiles you are mapping to Manually map nodes from the structure to FHIR (graphical mapping tool) Tools auto-generate transforms in both directions Rapid iterative map/test/map/test cycle Complex structure transforms are handled by mappings (e.g. flat => nested) Escape to code for tricky local requirements (e.g. map to Snomed codes) Open source runtime (Java, XSLT, more to come..) Need to know foundation concepts of mapping – training is available.

Making Mappings (V2 to FHIR example) V2 structure FHIR structure Examples for testing Mappings on Nodes Table view of mappings

Testing Mappings (V2 to FHIR) Summary test scores Result of V2 to FHIR transform ABA = V2 to FHIR to V2 round-trip AB = V2 to FHIR transform All test Result files Mappings being tested Example files used in this test A, B = codes for test files

Benefits of FHIR Mapping Defining one set of mappings is quicker and cheaper than writing code – to transform in 2 directions. Design decisions in mappings are open and reviewable; not hidden away in code Fast iterative development cycle (map/test/map/test..) Mappings are easy to maintain (e.g. as profiles evolve) Round-trips (FHIR => Native => FHIR) are free, self-consistent and testable Reduces costs of development, testing, maintenance Existing Implementations: PAS (FHIR mapped to Relational Database) HL7 V2 ADT to FHIR EMIS Open XML to FHIR

Healthcare Applications as FHIR Servers Client A Server B User Interface User Interface FHIR Transform Engine FHIR FHIR Transform Engine Business Logic Business Logic Relational Database Relational Database

FHIR RESTful Search FHIR servers have to support many RESTful searches By mapping FHIR directly onto a Relational DBMS: Mappings automatically translate RESTful search strings into SQL (RDBMS) or HQL (Hibernate), to do the required search. This supports many different types of search, without coding Uses database indexes for efficient retrieval You can still map to a higher-level API to use the application’s business logic (e.g. for updates) The runtime Transform Engine runs in a web server (e.g. Tomcat) This is the fastest way to create a FHIR server on an existing healthcare application