Martin Hurrell, Terri Monk, Alan Nicol Andrew Norton, David Reich, John Walsh

1. Implementation of a standards-based anesthesia record compliant with the Health Level 7 (HL7) Clinical Document Architecture (CDA) Martin Hurrell, Terri Monk, Alan Nicol Andrew Norton, David Reich, John Walsh

2. Acknowledgements Thanks to: Todd Cooper , Masaaki Hirai, Melvin Reynolds, John Rhoads and Jan Wittenber (HL7 Healthcare Devices WG) Bob Dolin and LioraAlshuler (HL7 Stuctured Documents WG)

3. “ We believe that one of the most influential developments for the practice of anaesthesia in this decade will be the introduction of a national (or possibly international) standard XML Schema for computerised anaesthetic records, and that such development should be actively promoted by appropriate professional groups.” Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic records. Anaesthesia, 2002, 57, pp1174-1182

4. Meaningful use EHR technology is "meaningful" when it has capabilities including  e-prescribing, exchanging electronic health information to improve the quality of care, having the capacity to provide clinical decision support to support practitioner order entry and submitting clinical quality measures - and other measures - as selected by the Secretary of Health and Human Services.

5. 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 applications, reasoning and decision support

6. AIMS in the real world • 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

7. Aspects of a solution Issue AIMS 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. Response Develop 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.

8. Aspects of a solution Issue There 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. Response Develop 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.

9. Aspects of a solution Issue There 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. Response Comprehensive and standardised representation in HL7 V3 CDA based on CEN ISO/IEEE 11073 standard

10. Different measurement techniques may not yield the same numbers “The objective of the study was assess the utility during anaesthesia of noninvasive continuous blood pressure measurement techniques which use intermittent oscillometric blood pressure measurement for their calibration. The assessment was performed by comparing noninvasive blood pressure with intra-arterial blood pressure.” “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 significant effect of site difference between calibration measurements and continuous measurements was not found. It is concluded that the approach of continuous noninvasive blood pressure measurement based on the combination of two different measurement methods, in which the continuous method is calibrated by the oscillometric method, lead to clinically unacceptable accuracy and agreement in the patient group studied.” De Jong JR, Ros HH, De Lange JJ. Int J ClinMonitComput. 1995 Feb;12(1):1-10 Noninvasive continuous blood pressure measurement during anaesthesia: a clinical evaluation of a method commonly used in measuring devices OTBP- oscillometrically calibrated tonometric blood pressure ITBP - intra-arterial calibrated tonometric pressure IBP - intra-arterial blood pressure

11. APSF DDTF / IOTA • Around 4,500 specialist terms for anaeshesia • - mapped to SNOMED CT

12. Standard Representation of the anaesthetic record

13. “ We believe that one of the most influential developments for the practice of anaesthesia in this decade will be the introduction of a national (or possibly international) standard XML Schema for computerised anaesthetic records, and that such development should be actively promoted by appropriate professional groups.” Gardner M., Peachey T. A Standard XML Schema for computerised anaesthetic records. Anaesthesia, 2002, 57, pp1174-1182

14. XML: self-defining? XML documents are human readable although depending upon the nature of the information they contain and the way in which they have been authored they may not always be easy to understand without supplementary information. A small fragment of an XML document might look like this: <Anesthesiologist> <Firstname>John</Firstname> <Lastname>Jones</Lastname> </Anesthesiologist> • ‘Anesthesiologist’, ‘Firstname’ and ‘Lastname’ are tags that identify XML elements • The elements ‘Firstname’ and ‘Lastname’ are nested within the element ‘Anesthesiologist’ • Deeper levels of nesting might be used to represent more complex structures.

15. However ... XML makes no commitment on: • Domain specific ontological vocabulary • Ontological modelling primitives Only feasible for closed collaboration • agents in a small & stable community • pages 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

16. Background • Terminology: APSF DDTF /IOTA Terminology mainly built on SNOMED CT with new material submitted for inclusion in SNOMED. Authoring done using Protégé-OWL. Vital signs closely aligned with X.73. • CDA Implementation Guide: In development by HL7 Anesthesiology WG An implementation guide for clinicians and IT specialists who wish to create anesthetic records as XML douments that validate against the HL7 V3 R2 (R3) CDA schema. This includes vital signs representation consistent with the ISO 11073 standard and guidance on value sets for different elements of the record taken from relevant clinical terminologies (ISO 11073 nomenclature standard, IOTA, SNOMED CT)

17. Major elements of the record • Record target (patient) • Author • Custodian • Related documents • Encompassing encounter • Case information • Operative Note • Safety checks • Vital signs • Drugs, fluids • Events • Intra-operative investigations • Notes

18. HL7 V3

19. RIM Core Classes

20. Example R-MIM Person classCode*: <= PSN determinerCode*: <= PSN id: II [1..1] name: EN [0..*] birthTime: TS [0..*]… Person A Patient subject Medical History Person B Practitioner performer 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. 1..1 patientPerson subject typeCode*: <= SBJ 1..1 patient Patient classCode*: <= PAT id*: II [1..1] addr: AD [0..1] telecom: TEL [0..*] Observation classCode* <= xy moodCode* <= xy id*: II [1..1] ... performer typeCode*: <= PRF time: IVL<TS> Person 1..1 practitioner Practitioner classCode*: <= PRT id*: II [1..1] telecom: TEL [0..*] playedBy scopedBy Organization

21. XML hierarchy Prescription EntryPoint author subject Person ClassCode*: <=PSN determinerCode*: <=PSN Name: EN [0..*] birthTime: TS [0..*] … Patient id addr Prescription classCode* <=SBADM moodCode) <=RQO Id*: || [1..1] Text: ED [0..1] statusCode: CS CNE [1..1] <=active 1..1 patientLivingSubject telecom 1..1 patient Person Patient ClassCode*: <=PAT Id*: || [1..1] addr: AD [0..*] Telecom: TEL [0..*] … subject typeCode*: <=SBJ name 1..1 assignedEntity CMET (Assigned) R_AssignedPerson [identified] COCT_MT090101 author typeCode*: <=AUT Time: IVL<TS>

22. HL7 CDA

23. What is the CDA? The CDA is a document markup standard for the structure and semantics of exchanged "clinical documents". A clinical document is a documentation of observations and other services with the following characteristics: • Persistence • Stewardship • Potential for authentication • Context • Wholeness • Human readability A CDA document is a defined and complete information object that can exist outside of a message, and can include text, images, sounds, and other multimedia content.

24. 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)

25. CDA Release 2 Information Model Start Here Header Body Participants Doc ID &Type Context Sections/Headings Clinical Statements/ Coded Entries Extl Refs

26. CDA Example Drug administration

27. CEN ISO/IEEE 11073

28. Why x.73? “The CEN ISO/IEEE 11073 standards are the only coherent standards that address medical device interconnectivity and have resulted in a single set of internationally harmonized standards that (a) have been developed and adopted via clinical and technical contributions from within ISO and CEN member countries and (b) include contributions from the most significant manufacturers” Reynolds M.I. (2008) Device Interfaces. In J. Stonemetz & K. Ruskin (Eds.), Anesthesia Informatics (pp.109-145). Springer-Verlag, London

29. Interoperability • Functional • Shared architectures, methods, frameworks and technologies CEN ISO/IEEE 11073: Domain Information Model (DIM) • Semantic • Shared data types, terminologies and coding systems CEN ISO/IEEE 11073: Nomenclature

30. x.73 DIM: Medical Package The 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.

31. x.73 DIM: Medical Package Patient monitor BP module NIBP values as complex numeric

32. x.73 NomenclatureNomenclature: general aims • The purpose of the device nomenclature is to support an identification scheme for the Channel, VMD, and MDS objects of the DIM. • The system provides enough information to support the data from the Metric and Channel objects, without replicating this information. For example, in the case of an airway gas analyzer, such a device may be measuring one, two, or more gases. The exact gases measured can be divined from the Metric object of the DIM that this device will be generating, i.e., O2, CO2, N2O, etc. and to include this level of detail in the device nomenclature is redundant.

33. x.73 Nomenclature: Coding [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=4100 is equal to (( 1 * 216 ) + 4100) = 65536 + 4100 = 69636 (which uniquely identifies the SpO2 monitor term

34. x.73 NomenclatureAttributes

35. x.73 NomenclatureBase concepts • Analyzer : devices that manipulate or interpret acquired data in order to produce derivative results • Calculator: devices that perform calculations upon raw or derived data • Filter: physical particle or chemical filters • Generator: devices that generate physical quantities such as heat, moisture, electrical activity, etc. • Meter : devices that perform measurement functions on physical properties such as current, electrical potential, flow, etc.) • Monitor : devices that both acquire data and analyze it • Stimulator: devices that generate physical quantities such as heat, moisture, electrical activity, etc. • System: instruments that consist of transducive, analytical, and therapeutic components. An anesthesia system and most ventilators would fall into this device class

36. x.73 NomenclatureMapping to IOTA & SNOMED CT IOTA-09527977651 SNOMED ID 09527977651

37. 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

38. Conclusions 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

39. HL7 WG GAS www.hl7.org “Out of cycle” meeting, London, 16th. / 17th. February martinhurrell@gmail.com

40. HL7 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

41. APSF DDTF / IOTA • Around 4,500 specialist terms for anaeshesia • - mapped to SNOMED CT

42. CDA Stuctures CDA Structures Entries

43. CDA outline structure <ClinicalDocument> ... <structuredBody> <section> <text>...</text> <observation>...</observation> <substanceAdministration> <supply>...</supply> </substanceAdministration> <observation> <referredToExternalObservation> ... </referredToExternalObservation> </observation> </section> <section> <section>...</section> </section> </structuredBody> </ClinicalDocument> HEADER BODY SECTION ENTRIES

44. x.73 NomenclatureFirst set of differentiating criteria Semantic link "has measured property: " Applicable descriptors include the following: • Concentration • ElectricalPotential • Flow • Multi-Parameter • Negative • Pressure • Rate • Resistance • Temperature • Volume

45. x.73 NomenclatureSecond set of differentiating criteria • Semantic link "has target: " • Applicable descriptors include the following: • Airway • Blood • Body • Brain • Gas • Heart • Infusion • Intra-Aorta • Lung • Multi-Gas • Muscle • Physiologic (for devices that are very general and not body-system-specific) • Renal • Resp • Skin/Tissue • Urine

46. x.73 NomenclatureThird set of differentiating criteria • Semantic link “device type: " • Applicable descriptors • include the following: • Channel • MDS • Non-specific • VMD • VMD Attributes (optional) • Acoustic • Chemical • Electrical • Impedance • Magnetic • Nuclear • Optical • Thermal