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Implementing Healthcare
Messaging with XML
Marc de Graauw
http://www.marcdegraauw.com
Dutch Healthcare
the use case
90.000 people
are hospitalized yearly due to
wrong medication
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Geography & Software Design
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Geography & Software Design
• How does geography affect software design?
• Canada
– 9,984,670 km²
– 33,115,600 inhabitants
– 3.2/km² density
• UK
– 244,820 km²
– 60,587,300 inhabitants
– 246/km² density
• The Netherlands
– 41,526 km²
– 16,570,613 inhabitants
– 395/km² density
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Geography & Software Design
• Canada
– is not densily populated
– infrastructure in remote areas not very dense nor very reliable
– different legislation regarding care and privacy in different
provinces
• UK
– relative dense population
– still some remoter areas
– National Health Service (actually 4, UK, Wales, Scotland, North
Ireland)
• The Netherlands
– densily populated
– dense infrastructure anywhere
– a single jurisdiction
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Healthcare
The Spine
Information
Messa- System
ging
Services
Healthcare
Patient Information
Registry System
Provider Healthcare
Registry Information
System
Clinical
Summary Healthcare
Information
System
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UK
• “The Spine” is the national backbone
• Healthcare Information Systems at
institutions and GP’s will not be online
permanently
• Contains clinical summary of medical data
needed for treatment
• Patient, provider registries et cetera
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Healthcare
Messa-
Clinical Provider Patient Information
ging
Summary Registry Registry System
Services
Healthcare
Information
System
Messa-
Clinical Provider Patient ging
Summary Registry Registry Services
Healthcare
Information
System
Messa-
Clinical Provider Patient ging Healthcare
Summary Registry Registry Services Information
System
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Canada
• iEHR (Interoperable Electronic Health Record)
per jurisdiction
• Different jurisdictions communicate through their
iEHR message services (HIAL’s)
• Healthcare Information Systems at institutions
and GP’s will not be online permanently
• Contains clinical summary of medical data
needed for treatment
• Patient, provider registries et cetera
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Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
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The Netherlands
• “AORTA” is the national backbone
• Healthcare Information Systems at
institutions and GP’s will be online 24x7
• No clinical data at backbone, only an index
of where clinical information resides
• Clinical data stays at the source
• Only possible with dense infrastructure
• Patient, provider registries et cetera
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NICTIZ
• (Dutch EHR Standards Organization)
• Timeline
– Medication File
– Primary Care Summary
• 2003: start
• 2006: Healthcare Information Broker delivered
• 2006/7: First HIS qualifications
• 2009: General availability
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Ministry of Healthcare
NICTIZ CIBG
National Healthcare
Institute for ICT Professionals
in Care Authority
SBV-Z
Healthcare UZI-Register
Unique Person Id
Information Healthcare
Registry Provider
Gov Broker Provider Registry
Market
Hospitals GP’s Pharmacists Others
Healthcare Healthcare
Regional
System Access
Facilities
Providers
Suppliers http://www.marcdegraauw.com
Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
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AORTA
• all messages go through healthcare
information broker
• three basic patterns:
– HIS sends message to other HIS, HIB just
routes
– HIS sends message to HIB (mainly for registry
updates and queries)
– HIS queries several other HISses, HIB does
registry lookups, accumulates data
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HIB
Healthcare
Message Information
to HIS System
Message Act
to HIB Registry
Healthcare
Information
Act System
Query Registry
(to multiple HIS)
Healthcare
Information
System
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Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
http://www.marcdegraauw.com
Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
http://www.marcdegraauw.com
Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
http://www.marcdegraauw.com
Healthcare
HIB Information
Messa- System
BSN (“Burger ging
Service Services
Nummer”) Healthcare
Registry Patient Information
Registry System
Provider Healthcare
Registry Information
UZI (PKI) System
Registry
Act
Registry Healthcare
Information
System
http://www.marcdegraauw.com
Just enough HL7
• HL7 version 2 : currently used
• HL7v3:
– XML based
– Reference Information Model
• HL7v3 Message contains:
– medical payload
– Trigger Event Wrappers (Query Control etc.)
– Transmission Wrapper
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HL7v3 Layered Model
HTTP, SSL
SOAP / Web Services
HL7 Transmission Wrapper
HL7 Query Control Wrapper
HL7 Medical Data
TCP
lower protocol layers
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Infrastructure example
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Actually, it’s not that simple...
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Schema Issues
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Schema's serve multiple masters
• Schema’s serve more than one purpose
– design
– validation
– contract
– code generation
• those purposes often need different
Schema’s
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Schema's serve multiple masters
• design
+ reuseability, composability, simplicity
- performance
• validation
+ performance, strictness, error messages, completeness
- reuseability, composability, simplicity, readability
• contract
+ readability, strictness, completeness
- performance
• code generation
+ simplicity, readability
- reuseability, composability
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The HL7v3 Schema’s
• Let’s look at an example
• Get Person Demographics Query
• Send in person id
• Get name, address, birthdate et cetera
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The HL7v3 Schema’s
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The HL7v3 Schema’s
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The HL7v3 Schema’s
• QUPA_101102_V01
• MCCI_MT000300UV01
– COCT_MT040203UV01
• COCT_MT150003UV03
• COCT_MT030203UV02
• MFMI_MT700711
– COCT_MT090300UV01
• COCT_MT150000UV02
– COCT_MT070000UV01
» COCT_MT710000UV01
• COCT_MT150003UV03
• COCT_MT070000UV01
– COCT_MT710000UV01
– COCT_MT090100
• COCT_MT150000UV02
– COCT_MT070000UV01
» COCT_MT710000UV01
• COCT_MT150003UV03
• COCT_MT070000UV01
– COCT_MT710000UV01
– COCT_MT090003
• COCT_MT150003UV03
– MCAI_MT900001
• QUPA_MT101102_V01
• QUPA_MT101101_V01
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The HL7v3 Schema’s
• The XML document, though abbreviated, isn’t
difficult
– (SOAP omitted here...)
– Transmission Wrapper: message-id, creation date
– Act Wrapper: query issuer etc.
– Payload: person-id
• The Schema is very simple
– 5 includes and 1 element
– but not very readable!
– the schema inclusion tree is very complex
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The HL7v3 Schema’s
• Schema’s should be readable
– tools can solve this
– but they make you dependent on the tool
• Therefore: flatten the Schema’s
– remove all includes
– put included schema’s where they belong
• For readability: make the Schema resemble the
instance
• Readable Schema’s generate readable code!
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Flatten the Schema’s
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The HL7v3 Schema’s
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The HL7v3 Schema’s
• HL7 datatypes
– TS: Point in Time
– CS: Simple Coded Value
– ST: Character String
• Translate to XSD
– datetime, string
• HL7 datatypes predate XSD datatypes
• With a lot of HL7 datatypes, nothing happens
except translation to XSD datatypes
• Do this in the source, generates much more
readable code
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Simplify the Schema’s
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Layering
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Initiating Application Responding Application
Medical Layer Medical Layer
Control Query Layer Control Query Layer
Transmission Layer Transmission Layer
Web Services Layer Web Services Layer
HTTP Layer
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HL7 Medical Application HL7v3
Medical
Content
HL7 Control Query Processing Application HL7v3
Acts
HL7 Transmission Wrapper Adapter
HL7v3
Messages
HL7 web services Messaging Adapter
SOAP
Messages
Server
HTTP Client / http://www.marcdegraauw.com
The HL7v3 Schema’s
• layer the Schema’s
• anonimyze with xs:any
– <xs:any namespace="##any"
processContents="skip" minOccurs="0"
maxOccurs="unbounded"/>
• SOAP Headers, soap:Body anon
• HL7 Transmission Wrapper, Act anon
• HL7 Act Wrapper, medical payload anon
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The HL7v3 Schema’s
• The Hl7 Schema’s were written with reuse
in mind
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SOAP
Transmission
Wrapper
Control
Wrapper
Medical
Data
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SOAP
ANY
Transmission
Wrapper
ANY
Control
Wrapper
ANY
Medical
Data
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Layer the Schema’s
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The HL7v3 Schema’s
flatten simplify layer
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The HL7v3 Schema’s
James Clark:
“validity is a relationship between a
document and a schema, not a property of
a document”
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The HL7v3 Schema’s
schema’s can be equivalent:
when two schema’s consider
the same set of documents valid
the schema’s are equivalent
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The HL7v3 Schema’s
don’t think of THE schema,
but the SCHEMAS
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VARIANTS
The HL7v3 Schema’s
V1b
V1a
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TIME
V1 V2 V3
Authentication
and Security
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Authentication
• Each Care Provider gets personal pass
– Smartcard (UZI pass)
– X.509 certificate
– PKI-Government
– Personal pass
• guard safely
• no sharing
• PIN protected
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Authentication with SSL
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Authentication alternatives
• Authentication token w. message
– X.509 one-way auth-style
• sign {nonce + timetolive + id}
– Kerberos-style
• ticket from HIB, encrypted w. public key
– WS-Security headers to transport the tokens
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Authentication alternatives
SOAP Envelope
SOAP Header
Auth Token
SOAP Body
HL7 payload
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Authentication alternatives
SOAP Envelope
SOAP Header
Auth Token
Auth Token
Auth Token
SOAP Body
HL7 payload
HL7 payload
HL7 payload
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HL7 Medical Application HL7v3
Medical
Content
HL7 Control Query Processing Application HL7v3
Acts
HL7 Transmission Wrapper Adapter
HL7v3
Messages
HL7 Web Services Messaging Adapter
SOAP
Messages
Server
HTTP Client / http://www.marcdegraauw.com
Authentication alternatives
• Authentication tokens in SOAP Headers
separate them from the content
• HL7 sometimes allows multiple payloads,
making this problem worse
• The token has to travel across layers with
the paylaod
• This violates layering principles
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WS-*
• WS-* is confused about whether it is a
document format or a message format
• document: relevant to the end user
• message: relevant to the mailman
• keep metadata with the document
• putting document metadata in SOAP
headers violates layering design principles
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Further points
• Make a lot of examples
– complex XML cannot be understood from
Schema alone
• Define your HTTP codes
• Define error handling on all levels
• Profile the Profiles
– Make a subset of WSDL, WS-
ReliableMessaging
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Questions?
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