a deep dive into fhir

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FHIR®

JAMES MCCLAY, MD, MS, FACEP, FAMIAEMERGENCY MEDICINE, UNIVERSITY OF NEBRASKA MEDICAL CENTER

A Deep Dive into FHIR


FHIR®FHIR | Agenda

• The basics: Resources and references• Structured and Coded Data• Terminology• Profiling• Ecosystem


FHIR®

BASICS OF FHIR


FHIR®Overview of FHIR

• Fast Healthcare Interoperability Resources (FHIR)• Consistent, simple to use content model (Resources)

• Controlled extensibility• Supports all paradigms of exchange

• Real-time APIs• Documents, Messages & Services

• Designed with implementers in mind• Detailed on-line, hyperlinked specification• Freely available tooling, servers, libraries• Written into latest HHS regulations


FHIR®Computable Healthcare Knowledge Artifacts

• The FHIR resources represent self contained computable healthcare knowledge artifacts.

• Computable knowledge artifacts are digital objects carrying healthcare information represented in data structures that can be parsed by a machine (Lehmann 2018).

• The FHIR Resource Objects represent named healthcare related concepts based on common EHR based concepts.

• The FHIR resources are designed to be findable, useable, extensible specifications based on standard internet protocols.

Lehmann HP, Downs SM. Desiderata for sharable computable biomedical knowledge for learning health systems. Learn Health Syst. 2018;2(4):e10065. https://onlinelibrary.wiley.com/doi/full/10.1002/ lrh2.10065.

https://onlinelibrary.wiley.com/doi/full/10.1002/


FHIR®Modeling Health Information

Clinical DataMedicationsDiagnosticsProblems and ConditionsProcedures and ResultsAllergiesFamily HistoryLabs, Radiology & Genomics…

Administrative DataPatient DemographicsProvider QualificationsEncounter DescriptionClaimsInsuranceOrganizational DescriptionsAppointmentsOrders management…Process Information

Care PlanningWorkflow SupportCare Episodes…

BasicsListsCompositionsBundlesLibrary


FHIR®Informed by and Related to other Healthcare Standards

• Health Level 7 (HL7)• Version 2• Version 3• CDA

• IHE• DICOM• Terminologies

• SNOMED• ICD• LOINC

Incorporates lessons learned from prior efforts

Iteratively designed by stakeholders and tested at regular connectathons.


FHIR®The FHIR Specification

http://hl7.org/fhir/

Free: licensed under Creative Commons ”derivative works allowed“

Fully Documented

Currently in 4th Release

Release 5 anticipated mid-2022

http://hl7.org/fhir/


FHIR®Resources: What are they?

• The Thing that is exchanged• Via REST ( FHIR Restful API), Messages, Documents

• The Content model• Small logically discrete units of exchange• Defined behaviour and meaning = FHIR

specification• Known identity / location• Smallest unit of transaction• “of interest” to healthcare


FHIR®Resources: How are they organized?

• https://www.hl7.org/fhir/overview-arch.html#framework

Clinical Research


FHIR®Resources:The FHIR Specification

http://hl7.org/fhir/resourcelist.htmlFive Level Maturity Model Applied to Each Resource:http://wiki.hl7.org/index.php?title=FHIR_Maturity_Model

http://hl7.org/fhir/resourcelist.html


FHIR®FHIR: the basics | Resource example: Patient

www.HL7.org/FHIR/patient

NAVIGATION HINT:

HL7.org/FHIR/NameOfResource

http://www.hl7.org/FHIR/patient


FHIR®FHIR the basics | References between resources

PROCEDURE

PATIENT

DIAGNOSTIC REPORTCONDITION

Subject

ReportRelated

Item

Encounter Performer

ENCOUNTER PRACTITIONER


FHIR®FHIR the basics |Recording a consultation

12-year-old-boy

First consultationComplaining of pain in the right ear for 3 days with an elevated temperature. On examination, temperature 38°C and an inflamed right eardrum with no perforation. Diagnosis Otitis Media, and prescribed Amoxicillin 250mg 3 times per day for 7 days.

Follow up consultation2 days later returned with an itchy skin rash. No breathing difficulties. On examination, urticarial rash on both arms. No evidence meningitis. Diagnosis of penicillin allergy. Antibiotics changes to Erythromycin 250mg 4 times per day for 10 days.

Patient

Encounter

Condition

Observation

Medication

Allergy Intolerance

Encounter

Encounter

Practitioner

PatientAsserter

Performer

Performer

Performer

Performer

Performer

Performer

Asserter

Asserter

Prescriber

Asserter

Pain right ear 3 days

Otitis media

Itchy skin rash

No breathing difficulties

Elevated temperature

Temperature 38°C

Inflamed right drum

Urticarial Rash

Amoxicillin 250mg

Erythromycin 250mg

Penicillin Allergy

As linked resources…

STRUCTURED AND CODED DATA


FHIR®Why have structured / coded data?

• Structured vs Coded• Structured:

• Organized according to a schema, e.g. relational database• Ex: a collection of recipes stored as ingredients, mixing instructions,

cooking instructions, serving instructions• Coded:

• Improves UI possibilities• Improves exchange• ‘Secondary’ uses

• Allows Decision Support• Population health

• HL7 New Zealand

Clinical Scenario

• First consultation– Complaining of pain in the r) ear for 3 days with an

elevated temperature. On examination, temperature 38.5 degrees and an inflamed r) ear drum with no perforation. Diagnosis Otitis Media, and prescribed Amoxil 250mg TDS for 5 days

• Follow up consultation– 5 days later returned with an itchy skin rash. No

breathing difficulties. On examination, urticarial rash on both arms. No evidence meningitis. Diagnosis of penicillin allergy. Antibiotics changes to erythromycin and advised not to take penicillin in the future.

Condition

Observation

Med

Adv React.

Allergy

Encounter

12 year old boyPatient

• HL7 New Zealand

Encounter

Encounter

Practitioner

Patient

Asserter

Performer

Performer

Performer

Performer

Performer

Performer

Asserter

Asserter

Prescriber

Asserter

Pain right ear 3 days

Otitis media

Itchy skin rash

No breathing difficulties

Elevated temperature

Temperature 38°C

Inflamed right drum

Urticarial Rash

Amoxicillin 250mg

Erythromycin 250mg

Penicillin Allergy

As linked resources…

• HL7 New Zealand

Organizing Resources: Lists of things

• Examples– Medication list– Problem List (Conditions)– Allergies– Past Medical History– Past Social History– Social History– ‘Organizer’ in Document

• Manage ‘points in time’ and changes

List

Coded datatypes• Code: "status" : "confirmed"• Coding: {

"system": "http://www.nlm.nih.gov/research/umls/rxnorm","code": "C3214954","display": "cashew nut allergenic extract Injectable"

}• CodeableConcept: {

"coding": [{ "system": "http://snomed.info/sct","code": "39579001","display": "Anaphylactic reaction“

}],"text" : "Anaphylaxis"

}


FHIR®Terminology Sub-system

Code System:Defines a set of concepts with a

coherent meaning

CodeDisplay

Definition

Element Definition: Type and Value set reference

Value Set:A selection of a set of codes for

use in a particular context

Selects Binds

Element: code/

Coding/CodeableConcept

Refers to

Conforms

• SNOMED CT / LOINC / RxNORM• ICPC, MIMS + 100s more• ICD-X+• A drug formulary• Custom

https://www.hl7.org/fhir/terminologies.html

https://www.hl7.org/fhir/terminology-service.html

https://www.hl7.org/fhir/terminologies.html

ValueSet{

"resourceType": "ValueSet","id": "condition-code",

"url": "http://hl7.org/fhir/ValueSet/condition-code","compose": {

"include": [

{"system": "http://snomed.info/sct","filter": [

{

"property": "concept","op": "is-a","value": "404684003"

}

]},{

"system": "http://snomed.info/sct","concept": [

{"code": "160245001",

"display": "No current problems or disability"}

]

}]

}}

n A context specific subset of one or more Code Systems

n Promotes consistency between applications

n Key component of TerminologyØ Also CodeSystem

n Target of a number of services


FHIR®ValueSet

n A subset of terms from a code system for a specific purpose or use case

n Promotes consistency between applications

n Key component of TerminologyØ Also CodeSystem

n Skin TonesØ PinkØ RuddishØ WhiteØ GrayØ Yellow

PROFILING


FHIR®Adapting FHIR to your needs: Profiling

• Many different contexts in healthcare, but want a single set of Resources for 1 context• Need to be able to describe ‘usage of FHIR’ based on context• Allow for these usage statements to:

• Authored in a structured manner• Published in a registry & discoverable• Used as the basis for validation, code, report and UI generation.

• 3 main aspects:• Constraining a resource - remove element, change multiplicity fix values• Change coded element binding• Adding a new element (an extension)

• Profiling adapts FHIR for specific scenarios


FHIR®For example…

Note: Limited mandatory elements in the core spec

Require that the identifier uses the NHS number – and is required

Limit names to just 1 (instead of 0..*)

Change maritalStatus to another set of codes that extends the one from HL7 international

Add an extension to support ethnicity

Doesn’t support photo


FHIR®The ‘profile’

• Defines each element • Path • Name • dataType• Binding • Multiplicity • Mapping & much more

• Including allowable extension points


FHIR®Extension Definitions

• Simple or Complex• Definition:

• Available on the web• Canonical Url

• Resolvable or Registry• In resource instance:

• Reference to Url• Extension or ModifierExtension

• Example: US Core – Patient Resource – Extended to include race and ethnicity.


FHIR®Messaging paradigm

• Notification or instruction• Not part of record• HL7 v2.x messages

• Good match with FHIR• Though implementations less common

• Work in progress


FHIR®Messages – are bundles

Observation Resource

MessageHeader Resourcesource destination

Device Resource

Patient Resource

<Bundle><entry>

<MessageHeader /></entry> <entry>

<Observation /></entry><entry>

<Patient /></entry><entry>

<Device /></entry>

</Bundle>

event


FHIR®Documents – are bundles

37

Observation Resource

Composition Resource

Section

Device Resource

Condition Resource

List Resource

<Bundle><entry>

<Composition /></entry> <entry>

<Observation /></entry><entry>

<Device /></entry><entry>

<List/></entry><entry>

<Condition/></entry>

</Bundle>

AttesterMetadata Section

Section


FHIR®REST (API)

• “Representational State Transfer” –architecture for how to connect systems in real time• Uses HTTP/S• Simple to use• Very commonly used outside of healthcare – especially mobile• For simple interactions

• Create• Read (& Query)• Update • Delete

• A lot of tooling / experience available

THE ECOSYSTEM


FHIR®Regardless of paradigm, the content is the same

Message

FHIRRepository

(FHIR Server)

REST


FHIR®Components


FHIR®FHIR Implementation Guides


Freely available

n Unencumbered – free for use, no membership requiredn http://hl7.org/fhir

47

http://hl7.org/fhir


FHIR®

o From HL7 o http://hl7.org/fhir/index.htmlo wiki.hl7.org/index.php?title=FHIRo http://www.fhir.org/

o Communityo https://chat.fhir.org/o List server ([email protected] )o Stack Overflow (tag FHIR)

o Blogso www.healthintersections.com.au/o https://fhirblog.com/o https://thefhirplace.com/o https://brianpos.com

n LibrariesØ Java (http://hapifhir.io/)Ø C# (NuGet HL7.FHIR)

n ToolingØ Forge (http://fhir.furore.com/Forge)Ø http://clinfhir.com/

n Test serversØ http://wiki.hl7.org/index.php?title=P

ublicly_Available_FHIR_Servers_for_testing

Ø https://fhirblog.com/2016/10/19/setting-up-your-own-fhir-server-for-profiling/

More information

https://thefhirplace.com/

http://wiki.hl7.org/index.php?title=Publicly_Available_FHIR_Servers_for_testing