Implementation of a standards-based Implementation of a standards-based anesthesia record compliant with the anesthesia record compliant with the

Health Level 7 (HL7) Clinical Health Level 7 (HL7) Clinical Document Architecture (CDA) Document Architecture (CDA)

Martin Hurrell, Terri Monk, Alan Nicol

Andrew Norton, David Reich, John Walsh

AcknowledgementsAcknowledgements

Thanks to:Thanks to:

Todd Cooper , Masaaki Hirai, Melvin Reynolds, John Rhoads Todd Cooper , Masaaki Hirai, Melvin Reynolds, John Rhoads

and Jan Wittenber and Jan Wittenber

(HL7 Healthcare Devices (HL7 Healthcare Devices WG)WG)

Bob Dolin and Liora Alshuler Bob Dolin and Liora Alshuler

(HL7 Stuctured Documents (HL7 Stuctured Documents WG)WG)

“ “ We believe that one of the most influential We believe that one of the most influential

developments for the practice of anaesthesia in developments for the practice of anaesthesia in

this decade will be the introduction of a this decade will be the introduction of a

national (or possibly international) standard national (or possibly international) standard

XML Schema for computerised anaesthetic XML Schema for computerised anaesthetic

records, and that such development should be records, and that such development should be

actively promoted by appropriate professional actively promoted by appropriate professional

groups.”groups.”

Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic records. Anaesthesia, 2002, 57, pp1174-1182records. Anaesthesia, 2002, 57, pp1174-1182

Meaningful useMeaningful use

EHR technology is "meaningful" when it has EHR technology is "meaningful" when it has

capabilities including  e-prescribing, capabilities including  e-prescribing, exchanging exchanging

electronic health information to improve the electronic health information to improve the

quality of carequality of care, having the capacity to provide , having the capacity to provide

clinical decision support to support practitioner clinical decision support to support practitioner

order entry and order entry and submitting clinical quality submitting clinical quality

measures - and other measures measures - and other measures - as selected - as selected

by the Secretary of Health and Human Servicesby the Secretary of Health and Human Services..

The anaesthetic record

• Purposes and uses– Medico-legal– ‘On-line’ document for decision support– Feed to the EHR– Audit & research

• Requirements for ‘meaningful use’– Common record structure to identify clinical

context

– Common terminology: for aggregation and analysis

– Common model:: to enable AI to enable AI applications, applications, reasoning and decision reasoning and decision

supportsupport

– Most AIMS systems do not currently use a standard vocabulary / terminology and so the representation of information may vendor specific and / or site specific

– The representation of data even within a site may not be consistent especially where free text entries are allowed

– There are a number of issues surrounding the comparability of automatically recorded vital signs data e.g. pre-processing etc.

– Data from different systems are not organised with reference to a consistent model of the anaesthetic process

AIMS in the real worldAIMS in the real world

Aspects of a solutionAspects of a solution

IssueAIMS systems do not currently use a standard vocabulary / terminology and so the representation of information may be site specific or even specific to individuals making effective aggregation difficult.

ResponseDevelop and promote a standard vocabulary / terminology and a data dictionary which, together, provide unambiguous definitions of the individual terms and guidance on their intended context of use.

Aspects of a solutionAspects of a solution

IssueThere is no standard representation for the anaesthetic record and data from different systems are not organised with reference to a consistent model of the anaesthetic process.

ResponseDevelop implementation guidelines tor the anaesthetic record that is based on an international standard (HL7 Clinical Document Architecture). The HL7 Anesthesiology WG is working on an implementation guide in partnership with the Structured Documents WG and Healthcare Devices WG.

Aspects of a solutionAspects of a solution

IssueThere are a number of issues surrounding the comparability of automatically recorded vital signs data e.g. detailed information concerning provenance is unavailable, differences in sampling rates, pre-processing etc.

ResponseComprehensive and standardised representation in HL7 V3 CDA based on CEN ISO/IEEE 11073 standard

““The objective of the study was assess the utility during anaesthesia of noninvasive The objective of the study was assess the utility during anaesthesia of noninvasive continuous blood pressure measurement techniques which use intermittent continuous blood pressure measurement techniques which use intermittent oscillometric blood pressure measurement for their calibration. The assessment was oscillometric blood pressure measurement for their calibration. The assessment was performed by comparing noninvasive blood pressure with intra-arterial blood performed by comparing noninvasive blood pressure with intra-arterial blood pressure.” pressure.”

““Accuracy and agreement of OTBP-IBP and of OTBP-ITBP were not clinically Accuracy and agreement of OTBP-IBP and of OTBP-ITBP were not clinically acceptable. Correlation of dynamic behavior was lower for OTBP than for ITBP. A acceptable. Correlation of dynamic behavior was lower for OTBP than for ITBP. A significant effect of site difference between calibration measurements and continuous significant effect of site difference between calibration measurements and continuous measurements was not found. It is concluded that the approach of continuous measurements was not found. It is concluded that the approach of continuous noninvasive blood pressure measurement based on the combination of two different noninvasive blood pressure measurement based on the combination of two different measurement methods, in which the continuous method is calibrated by the measurement methods, in which the continuous method is calibrated by the oscillometric method, lead to clinically unacceptable accuracy and agreement in the oscillometric method, lead to clinically unacceptable accuracy and agreement in the patient group studied.”patient group studied.”

De Jong JR, Ros HH, De Lange JJ. Int J Clin Monit Comput. 1995 Feb;12(1):1-10 Noninvasive continuous blood De Jong JR, Ros HH, De Lange JJ. Int J Clin Monit Comput. 1995 Feb;12(1):1-10 Noninvasive continuous blood pressure measurement during anaesthesia: a clinical evaluation of a method commonly used in measuring devicespressure measurement during anaesthesia: a clinical evaluation of a method commonly used in measuring devices

OTBP- oscillometrically calibrated tonometric blood pressure OTBP- oscillometrically calibrated tonometric blood pressure

ITBP - intra-arterial calibrated tonometric pressure ITBP - intra-arterial calibrated tonometric pressure

IBP IBP - - intra-arterial blood pressureintra-arterial blood pressure

Different measurement techniques may not yield the same numbers

APSF DDTF / IOTAAPSF DDTF / IOTA

Around 4,500 specialist terms for anaeshesia - mapped to SNOMED CT

Standard Standard RepresentationRepresentation

of the anaesthetic of the anaesthetic recordrecord

“ “ We believe that one of the most influential We believe that one of the most influential

developments for the practice of anaesthesia in developments for the practice of anaesthesia in

this decade will be the introduction of a this decade will be the introduction of a

national (or possibly international) standard national (or possibly international) standard

XML Schema for computerised anaesthetic XML Schema for computerised anaesthetic

records, and that such development should be records, and that such development should be

actively promoted by appropriate professional actively promoted by appropriate professional

groups.”groups.”

Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic records. Anaesthesia, 2002, 57, pp1174-1182records. Anaesthesia, 2002, 57, pp1174-1182

XML: self-defining?XML: self-defining?

XML documents are human readable although depending upon the nature XML documents are human readable although depending upon the nature of the information they contain and the way in which they have been of the information they contain and the way in which they have been authored they may not always be easy to understand without authored they may not always be easy to understand without supplementary information. A small fragment of an XML document might supplementary information. A small fragment of an XML document might look like this:look like this:

<<AnesthesiologistAnesthesiologist>>

   <<FirstnameFirstname>>JohnJohn</</FirstnameFirstname> >

   <<LastnameLastname>>JonesJones</</LastnameLastname> >

   </</AnesthesiologistAnesthesiologist>>

•‘‘Anesthesiologist’, ‘Firstname’ and ‘Lastname’ are tags that identify XML Anesthesiologist’, ‘Firstname’ and ‘Lastname’ are tags that identify XML elementselements•The elements ‘Firstname’ and ‘Lastname’ are nested within the element The elements ‘Firstname’ and ‘Lastname’ are nested within the element ‘Anesthesiologist’ ‘Anesthesiologist’ •Deeper levels of nesting might be used to represent more complex Deeper levels of nesting might be used to represent more complex structures. structures.

However ...However ...

XML makes no commitment on:XML makes no commitment on:• Domain specific ontological Domain specific ontological vocabularyvocabulary• Ontological Ontological modelling primitivesmodelling primitives

Only feasible for closed collaborationOnly feasible for closed collaboration• agents in a small & stable communityagents in a small & stable community• pages on a small & stable intranetpages on a small & stable intranet

Requires pre-agreement … on both

“ In reality, XML just clears away some of the syntactical distractions so that we can get down to the big problem: how we arrive at common understandings about knowledge representation” Jon Bosak

BackgroundBackground

• Terminology: APSF DDTF /IOTATerminology: APSF DDTF /IOTATerminology mainly built on SNOMED CT with new material Terminology mainly built on SNOMED CT with new material submitted for inclusion in SNOMED. Authoring done using submitted for inclusion in SNOMED. Authoring done using Protégé-OWL. Vital signs closely aligned with X.73.Protégé-OWL. Vital signs closely aligned with X.73.

• CDA Implementation Guide: In development by HL7 CDA Implementation Guide: In development by HL7 Anesthesiology WGAnesthesiology WGAn implementation guide for clinicians and IT specialists who An implementation guide for clinicians and IT specialists who

wish to create anesthetic records as XML douments that wish to create anesthetic records as XML douments that validate against the HL7 V3 R2 (R3) CDA schema. This validate against the HL7 V3 R2 (R3) CDA schema. This includes vital signs representation consistent with the ISO includes vital signs representation consistent with the ISO 11073 standard and guidance on value sets for different 11073 standard and guidance on value sets for different elements of the record taken from relevant clinical elements of the record taken from relevant clinical terminologies (ISO 11073 nomenclature standard, IOTA, terminologies (ISO 11073 nomenclature standard, IOTA, SNOMED CT)SNOMED CT)

Major elements of the recordMajor elements of the record

o Record target (patient)o Authoro Custodiano Related documentso Encompassing encounterEncompassing encountero Case informationCase informationo Operative NoteOperative Noteo Safety checksSafety checkso Vital signsVital signso Drugs, fluidsDrugs, fluidso EventsEventso Intra-operative investigationsIntra-operative investigationso NotesNotes

HL7 V3HL7 V3

Act ReferralSupplyProcedure ObservationMedicationFinancial act

Participation PerformerAuthorWitnessSubjectDestination

Entity Living SubjectPersonOrganizationPlaceHealth Chart Material

Act-relationship

CompositionalReferenceSucceeds

Role EmployeePatientScheduled ResourceCertified PractitionerAssigned PractitionerSpecimen

Role-link Direct AuthorityIndirect AuthorityReplacesPartBackup

RIM Core Classes

Practitioner

PersonclassCode*: <= PSNdeterminerCode*: <= PSNid: II [1..1]name: EN [0..*]birthTime: TS [0..*]…

PatientclassCode*: <= PATid*: II [1..1]addr: AD [0..1]telecom: TEL [0..*]

PractitionerclassCode*: <= PRTid*: II [1..1]telecom: TEL [0..*]

subjecttypeCode*: <= SBJ

performertypeCode*: <= PRFtime: IVL<TS>

ObservationclassCode* <= xymoodCode* <= xyid*: II [1..1]

...

Person

Organization

playedBy

scopedBy

1..1 patientPerson

1..1 patient

1..1 practitioner

Person A

Person B

Patient subject

performer

Medical History

Example R-MIM

The green box at the top left depicts an entity ‘Person’ who is playing a role, ‘Patient’ and who participates in an act, ‘Observation’ as the ‘subject’. A second person plays the role ‘Practitioner’ and is scoped by (belongs to) an ‘Organization’ (which might be specifically identified). This person participates in the observation act as the performer of the act. Other attributes can be defined for each class to add more information and specificity to the model.

XML hierarchyXML hierarchy

PersonClassCode*: <=PSNdeterminerCode*: <=PSNName: EN [0..*]birthTime: TS [0..*] …

EntryPoint

subjecttypeCode*: <=SBJ

authortypeCode*: <=AUTTime: IVL<TS>

PrescriptionclassCode* <=SBADMmoodCode) <=RQOId*: || [1..1]Text: ED [0..1]statusCode: CS CNE [1..1] <=activePatient

ClassCode*: <=PATId*: || [1..1]addr: AD [0..*]Telecom: TEL [0..*] …

CMET (Assigned)R_AssignedPerson

[identified]COCT_MT090101

1..1 patientLivingSubject

1..1 patient

1..1 assignedEntity

Prescription author

subject

Patient

id

addr

telecom

Person

name

HL7 CDAHL7 CDA

What is the CDA?What is the CDA?

The CDA is a document markup standard for the structure and semantics The CDA is a document markup standard for the structure and semantics of exchanged "clinical documents".of exchanged "clinical documents".

A clinical document is a documentation of observations and other services A clinical document is a documentation of observations and other services with the following characteristics:with the following characteristics:

•PersistencePersistence•StewardshipStewardship•Potential for authenticationPotential for authentication•ContextContext•WholenessWholeness•Human readabilityHuman readability

A CDA document is a defined and complete information object that can A CDA document is a defined and complete information object that can exist outside of a message, and can include text, images, sounds, and exist outside of a message, and can include text, images, sounds, and other multimedia content.other multimedia content.

What is the CDA?What is the CDA?

The CDA Header identifies and classifies the document and provides information on:

•Authentication, •Encounter•Patient•Provider

The body contains the clinical report•CDA body structures

– section, paragraph, list, table, caption– structures, including <body> can have own confidentiality,

originator•CDA body entries

– text, link, codes, content, images (multi-media)

CDA Release 2 CDA Release 2 Information Model Information Model

28

Header Body

ParticipantsSections/Headings

Clinical Statements/Coded EntriesContext

Doc ID&Type

StartHere

ExtlRefs

CDA Example CDA Example Drug administrationDrug administration

CEN ISO/IEEE 11073CEN ISO/IEEE 11073

““The CEN ISO/IEEE 11073 standards are the only coherent The CEN ISO/IEEE 11073 standards are the only coherent standards that address medical device interconnectivity and standards that address medical device interconnectivity and have resulted in a single set of internationally harmonized have resulted in a single set of internationally harmonized standards that (a) have been developed and adopted via standards that (a) have been developed and adopted via clinical and technical contributions from within ISO and CEN clinical and technical contributions from within ISO and CEN member countries and (b) include contributions from the member countries and (b) include contributions from the most significant manufacturers”most significant manufacturers”

Reynolds M.I. (2008) Device Interfaces. In J. Stonemetz & K. Reynolds M.I. (2008) Device Interfaces. In J. Stonemetz & K. Ruskin (Eds.), Anesthesia Informatics (pp.109-145). Springer-Ruskin (Eds.), Anesthesia Informatics (pp.109-145). Springer-Verlag, LondonVerlag, London

Why x.73?

InteroperabilityInteroperability

• FunctionalFunctional

– Shared architectures, methods, frameworks and technologiesShared architectures, methods, frameworks and technologies

CEN ISO/IEEE 11073: Domain Information Model (DIM)CEN ISO/IEEE 11073: Domain Information Model (DIM)

• SemanticSemantic

– Shared data types, terminologies and coding systemsShared data types, terminologies and coding systems

CEN ISO/IEEE 11073: NomenclatureCEN ISO/IEEE 11073: Nomenclature

x.73 DIM: Medical PackageThe VMO is the base class for all medical-related objects in the model. It provides consistent naming and identification across the Medical Package model.

The VMD object is an abstraction for a medical-related subsystem (e.g., hardware or even pure software) of a medical device. Characteristics of this subsystem (e.g., modes, versions) are captured in this object. At the same time, the VMD object is a container for objects representing measurement and status information.

The Channel object is used for grouping Metric objects and, thus, allows hierarchical information organization. The Channel object is not mandatory for representation of Metric objects in a VMD.

x.73 DIM: Medical Package

Patient monitor

BP module

NIBP values as complex numeric

x.73 Nomenclaturex.73 NomenclatureNomenclature: general aims Nomenclature: general aims

– The purpose of the device nomenclature is to support an The purpose of the device nomenclature is to support an identification scheme for the Channel, VMD, and MDS objects of identification scheme for the Channel, VMD, and MDS objects of the DIM.the DIM.

– The system provides enough information to support the data The system provides enough information to support the data from the Metric and Channel objects, without replicating this from the Metric and Channel objects, without replicating this information. For example, in the case of an airway gas analyzer, information. For example, in the case of an airway gas analyzer, such a device may be measuring one, two, or more gases. The such a device may be measuring one, two, or more gases. The exact gases measured can be divined from the Metric object of exact gases measured can be divined from the Metric object of the DIM that this device will be generating, i.e., O2, CO2, N2O, the DIM that this device will be generating, i.e., O2, CO2, N2O, etc. and to include this level of detail in the device etc. and to include this level of detail in the device nomenclature is redundant.nomenclature is redundant.

x.73 Nomenclature: Coding

31 . . . . . . 23 . . . . . . . 15 . . . . . . . 7 . . . . . .0

msblsb

Codeblock Number (Hi-order 16 bits)

1 Object-Oriented (OO)2 Supervisory Control and Data

Acq’n (SCADA)3 Events4 Dimensions (Units of Msmt)5 Virtual Attributes6 Parameter Groups7 [Body] Sites8 Infrastructure…256 External Nomenclature Ref's…1024 Private

Term Code (Lo-order 16 bits)Context-sensitive parts

Context-free code

[context-free] Nomenclature Code == (Code Block number * 216 ) + [contextsensitive]Term Code, where Term Code has the range 216.

Example: the context-free nomenclature code for a term in code block number 1 whose term code=4100is equal to (( 1 * 216 ) + 4100) = 65536 + 4100 = 69636 (which uniquely identifies the SpO2 monitor term

x.73 Nomenclaturex.73 NomenclatureAttributesAttributes

Attribute Description/Definition Purpose Interpretability PresenceSystematic, or DIMname An organization of

differentiating, relational descriptors

Formal or semiformal but human-readable derivation

Shall be unambiguous Mandatory

Common termA brief description of the name

Human-readable identification or efficient lookup

Should be unambiguousOptional

AcronymAn abbreviated form of the name

Mnemonic or parametric abbreviation

Should be unambiguousOptional

Description/ Definition A long, or sentence, form of the name

Human-readable and as understandable as possible

Shall be unambiguous with the exception of synonyms

Mandatory

Reference IDA symbolic, programmatic form of the term

Development of application program interfaces (APIs)

Shall be unambiguous Mandatory

Code [Alpha]numeric identifier Human- and machine-read-able and efficiently processable by machines

Shall be unique, but context-sensitive parts are permitted; see 7.2

Mandatory

x.73 Nomenclaturex.73 NomenclatureBase conceptsBase concepts

– AnalyzerAnalyzer : devices that manipulate or interpret acquired data in : devices that manipulate or interpret acquired data in order to produce derivative resultsorder to produce derivative results

– Calculator:Calculator: devices that perform calculations upon raw or devices that perform calculations upon raw or derived dataderived data

– Filter:Filter: physical particle or chemical filters physical particle or chemical filters– Generator:Generator: devices that generate physical quantities such as devices that generate physical quantities such as

heat, moisture, electrical activity, etc.heat, moisture, electrical activity, etc.– MeterMeter : devices that perform measurement functions on physical : devices that perform measurement functions on physical

properties such as current, electrical potential, flow, etc.)properties such as current, electrical potential, flow, etc.)– MonitorMonitor : devices that both acquire data and analyze it : devices that both acquire data and analyze it– Stimulator:Stimulator: devices that generate physical quantities such as devices that generate physical quantities such as

heat, moisture, electrical activity, etc.heat, moisture, electrical activity, etc.– System:System: instruments that consist of transducive, analytical, and instruments that consist of transducive, analytical, and

therapeutic components. An anesthesia system and most therapeutic components. An anesthesia system and most ventilators would fall into this device classventilators would fall into this device class

x.73 Nomenclaturex.73 NomenclatureMapping to IOTA & SNOMED CTMapping to IOTA & SNOMED CT

Systematic name Common term Acronym Description/Definition Reference ID CodeRate | Beats | Heart | CVS Heart rate HR Rate of cardiac beats MDC_ECG_HEART_RATE 16770

An organization of differentiating, relational descriptors

A symbolic, programmatic form of the term

Formal or semiformal but human-readable derivation

Development of application program interfaces (APIs)

IOTA-09527977651 SNOMED ID 09527977651

Modelling

•Use Case(s)•Activity Diagram(s)•Glossary•UML Model (X73 and Drug Modelling, included)     

MDHT (Model Drive Health Tools)

•Constrained CDA Model•Implementation Guide•Java Library

ConclusionsConclusions

In order to facilitate / ensure interoperability with EMRs and to allow data from anesthetic records to be fully utilised for audit the pre-requisites are:

–A standard nomenclature that fully and unambiguously describes data collected from patient-connected devices during anaesthesia

–A standard way to represent the anaesthetic record that provides full contextual information that will allow data derived from devices to be analysed and interpreted correctly

It is hoped that the combination of the IOTA / SNOMED CT terms for anaesthesia, the CEN ISO/IEEE 11073 standard and the implementation of the HL7 V3 CDA-compliant anaesthesia record specification proposed by the HL7 Anesthesiology WG will support these aims

HL7 WG GASHL7 WG GASwww.hl7.orgwww.hl7.org

“Out of cycle” meeting, London, 16th. / 17th. February

martinhurrell@gmail.com

HL7 WG GAS ProjectsHL7 WG GAS Projects

• Pre-operative assessment domain analysis model

• Anesthetic record domain analysis model

• CDA Implementation Guide for Anaesthetic Record including references to IHE technical framework

– Proof of concept – transfer of data from MGH AIMS to US NSQIP database via generic representation

APSF DDTF / IOTAAPSF DDTF / IOTA

Around 4,500 specialist terms for anaeshesia - mapped to SNOMED CT

Entries

CDA StucturesCDA Stuctures

CDA Structures

CDA outline structureCDA outline structure

<ClinicalDocument><ClinicalDocument> ...... <structuredBody><structuredBody> <section><section> <text>...</text><text>...</text> <observation>...</observation><observation>...</observation> <substanceAdministration><substanceAdministration> <supply>...</supply><supply>...</supply> </substanceAdministration></substanceAdministration> <observation><observation> <referredToExternalObservation><referredToExternalObservation> ...... </referredToExternalObservation></referredToExternalObservation> </observation></observation> </section></section> <section><section> <section>...</section><section>...</section> </section></section> </structuredBody></structuredBody></ClinicalDocument></ClinicalDocument>

HEADER

x.73 Nomenclaturex.73 NomenclatureFirst set of differentiating criteriaFirst set of differentiating criteria

Semantic link "Semantic link "has measured propertyhas measured property: ": "

Applicable descriptors include the following:Applicable descriptors include the following:

– ConcentrationConcentration– ElectricalPotentialElectricalPotential– FlowFlow– Multi-ParameterMulti-Parameter– NegativeNegative– PressurePressure– RateRate– ResistanceResistance– TemperatureTemperature– VolumeVolume

x.73 Nomenclaturex.73 NomenclatureSecond set of differentiating criteriaSecond set of differentiating criteria

– AirwayAirway– BloodBlood– BodyBody– BrainBrain– GasGas– HeartHeart– InfusionInfusion– Intra-AortaIntra-Aorta– LungLung– Multi-GasMulti-Gas

Semantic link "has target: "Applicable descriptors include the following:

– MuscleMuscle– Physiologic (for devices that are Physiologic (for devices that are

very general and not body-very general and not body-system-specific)system-specific)

– RenalRenal– RespResp– Skin/TissueSkin/Tissue– UrineUrine

x.73 Nomenclaturex.73 NomenclatureThird set of differentiating criteriaThird set of differentiating criteria

– ChannelChannel– MDSMDS– Non-specificNon-specific– VMDVMD

Semantic link “device type: "Applicable descriptors include the following:

VMD Attributes (optional)VMD Attributes (optional)– AcousticAcoustic– ChemicalChemical– ElectricalElectrical– ImpedanceImpedance– MagneticMagnetic– NuclearNuclear– OpticalOptical– ThermalThermal