HL7 Version 3 Overview

Editor's Notes

• #4: Instructor: Introduce yourself The notes provide you with additional information on slide topic.
• #5: At the end of this training you should: Understand what HL7 is Define terms and concepts used in HL7 Read HL7 RIM based models HL7 at the NCI
• #6: In this section, we will: Goal of HL7 4 Pillars of semantic interoperability
• #7: The goal of HL7 is HL7 V3 is a standard for exchanging messages among information systems that implement healthcare applications. To accomplish this, HL7 uses an object-oriented development methodology and is based on a Reference Information Model (RIM) to create messages. The goal of HL7 is semantic interoperability. What Does the Name HL7 Mean "Level Seven" refers to the highest level of the International Standards Organization's (ISO) communications model for Open Systems Interconnection (OSI) - the application level. The application level addresses definition of the data to be exchanged, the timing of the interchange, and the communication of certain errors to the application. The seventh level supports such functions as security checks, participant identification, availability checks, exchange mechanism negotiations and, most importantly, data exchange structuring. How is HL7 Organized HL7 is managed by a Board of Directors, which is comprised of eight elected positions and three appointed positions. The organization is comprised of Technical Committees and Special Interest Groups that are responsible for defining the HL7 standard protocol. Each Technical Committee and Special Interest group is chaired by two or more co-chairs. Collectively, the co-chairs comprise the Technical Steering Committee, which votes on issues related to the standard. Votes of the Technical Steering Committee as passed as recommendations to the Board of Directors, who make the final decision. HL7 members are encouraged to participate in all of these committees.
• #8: The 4 Pillars: The following slides will discuss these pillars. The Reference Information Model (RIM) The Reference Information Model (RIM) is the cornerstone of the HL7 Version 3 development process. An object model created as part of the Version 3 methodology, the RIM is a large pictorial representation of the clinical data (domains) and identifies the life cycle of events that a message or groups of related messages will carry. It is a shared model between all the domains and as such is the model from which all domains create their messages. Explicitly representing the connections that exist between the information carried in the fields of HL7 messages, the RIM is essential to our ongoing mission of increasing precision and reducing implementation costs. Data Types Data types are the basic building blocks of attributes. They define the structural format of the data carried in the attribute and influence the set of allowable values an attribute may assume. Some data types have very little intrinsic semantic content and the semantic context for that data type is carried by its corresponding attribute. However HL7 also defines quite extensive data types such as PNMP, person Name Part, which provides all the structure and semantics to support a person name. Every attribute in the RIM is associated with one and only one data type, and each data type is associated with zero or many attributes. Data Exchange Specifications HL7 defines its messages at an abstract level. The "7" in HL7 stands for the Application level of the ISO communication model -- ISO level 7. The V3 abstract message model is based on the RIM. HL7 Version 3 messages can be thought of as the communication of graphs of RIM objects from sender to receiver. Vocabulary Within HL7, a vocabulary domain is the set of all concepts that can be taken as valid values in an instance of a coded field or attribute. For example, the Living_subject class has a coded attribute called administrative_gender_code. The administrative_gender_code attribute becomes part of an HMD, and a message instance is subsequently created as part of an implemented interface, one would expect the administrative_gender_code attribute to convey male or female. In this example, male and female are concepts and there may be several coding schemes that contain concepts for male and female.
• #10: The Health Level Seven (HL7) Reference Information Model (RIM) is a static model of health and health care information as viewed within the scope of HL7 standards development activities. It is the combined consensus view of information from the perspective of the HL7 working group and the HL7 international affiliates. The RIM is the ultimate source from which all HL7 version 3.0 protocol specification standards draw their information-related content. What is a information model? An information model is a structured specification of the information within a specific domain of interest. It expresses the classes of information required and the properties of those classes, including attributes, relationships, constraints, and states. In HL7, the scope of a domain of interest ranges from the domain of the entire system of health services to the specific context of a set of information exchanges to meet a particular identified business purpose. HL7 defines different types of information models to represent the different contexts of interest Information Model Components The information model consists of the following components:    classes, their attributes, and relationships between the classes; data types for all attributes and vocabulary domains for coded attributes; state transition models for some classes. HL7 information models are based upon the Unified Modeling Language (UML), and may be represented graphically using the UML style. UML is a modeling language that unifies the object-oriented modeling methods of Grady Booch, Jim Rumbaugh, Ivar Jacobson, and others. The UML is a rich, mainly graphical, means of expressing object-oriented concepts. To obtain more information about UML see http://www.rational.com/uml/ or the book UML Distilled by Martin Fowler (ISBN 0-201-32563-2).
• #11: Note: RIM model is color coded based on the backbone class. The HL7 RIM The HL7 RIM is a critical component of the V3 development process. It is the root of all information models and structures. The HL7 V3 development process is a model-driven methodology. Inter-related models are developed that depict underlying semantics and business rules that govern them. The RIM provides a static view of the information needs of HL7 V3 standards. It includes class and state-machine diagrams and is accompanied by use case models, interaction models, data type models, terminology models, and other types of models. The classes, attributes, state-machines, and relationships in the RIM are used to derive domain-specific information models. The HL7 V3 standard development process defines the rules governing the derivation of domain information models from the RIM and the refinement of those. The rules require that all information structures in derived models be traceable back to the RIM and that their semantic and related business. The RIM therefore is the ultimate source for all information content in HL7 V3 standards.  Examples of Subclasses of Foundation Classes: Entity - Organization - Place - Person - Living Subject - Material Role - Patient - Member - Healthcare facility - Practitioner - Practitioner assignment - Specimen - Location Participation - Author - Reviewer - Verifier - Subject - Target - Tracker - Performer Act - Referral - Transportation - Supply - Procedure - Consent - Observation - Medication - Administrative act - Financial act
• #12: Note: classes are not the only.. The only ones show are the ones that have unique attributes Definition of Entity: A physical thing, group of physical things or an organization capable of participating in Acts, while in a role.
• #13: Note: classes are not the only.. The only ones show are the ones that have unique attributes Definition of Role: A competency of the Entity playing the Role as identified, defined, guaranteed, or acknowledged by the Entity that scopes the Role.
• #14: Definition of RoleLink: A connection between two roles expressing a dependency between those roles. Examples: A role of assignment or agency depends on another role of employment, such that when the employment role is terminated, the assignments would be terminated as well. This is the dependency of the assignment role with the employment role, or in other words, the assignment is "part of" the employment.
• #15: Note: classes are not the only.. The only ones show are the ones that have unique attributes Definition of Participation: An association between an Act and a Role with an Entity playing that Role. Each Entity (in a Role) involved in an Act in a certain way is linked to the act by one Participation-instance. The kind of involvement in the Act is specified by the Participation.typeCode.
• #16: Note: classes are not the only.. The only ones show are the ones that have unique attributes Definition of Act: A record of something that is being done, has been done, can be done, or is intended or requested to be done. Examples: The kinds of acts that are common in health care are (1) a clinical observation, (2) an assessment of health condition (such as problems and diagnoses), (3) healthcare goals, (4) treatment services (such as medication, surgery, physical and psychological therapy), (5) assisting, monitoring or attending, (6) training and education services to patients and their next of kin, (7) and notary services (such as advanced directives or living will), (8) editing and maintaining documents, and many others.
• #17: Definition of ActRelationship: A directed association between a source Act and a target Act. ActRelationship on the same source Act are called the "outbound" act relationships of that Act. ActRelationships on the same target Act are called the "inbound" relationships of that Act. The meaning and purpose of an ActRelationship is specified in the ActRelationship.typeCode attribute.
• #18: Understanding the RIM The RIM uses a abstract modeling style. The back-bone classes of the RIM and their structural attributes are its core. An understanding of these classes and attributes are essential to understanding the RIM. Defines all the information from which the data content of HL7 messages are drawn Follows object-oriented modeling techniques, where the information is organized into classes that have attributes and that maintain associations with other classes Forms a shared view of the information domain used across all HL7 messages independent of message structure Provides a means for discovering and reconciling differences in data definition
• #21: Notes about HL7 processes … message are derived from the RIM. Focus on the model methodology of DMIM and RMIM. People will be looking at the RMIM.
• #22: color-coded colors denotes type of backbone class Red = Act Blue = Participation Yellow = Role Green = Entity Light red or pink = Act Relationship Light Yellow = Role Link Arrows Participations, Role_Links and Act_Relationships are arrows that are directional have attributes rather than being lines that connect classes like in UML Entry Point Each D-MIM diagram will have at least one Entry Point. Entry Points designate the class(es) from which the messages begin for the particular domain. Since the D-MIM encompasses an entire domain, there may be several Entry Points, one for each R-MIM contained in the domain. Entry Point Each D-MIM diagram will have at least one Entry Point. Entry Points designate the class(es) from which the messages begin for the particular domain. Since the D-MIM encompasses an entire domain, there may be several Entry Points, one for each R-MIM contained in the domain. RMIMs are directional All associations flow out from the entry point toward the remaining parts of the message labeling HL7 diagrams are a little different in how they label associations (only on distal end, not bi-directional) Normally in UML diagrams you have a label on both ends of an association and the association can be read both ways, but in an HL7 RMIM the association can only be read one way and thus there is only one label and it's on the distal (far) end of the association
• #23: HL7 Modeling Conventions color-coded - colors mean type of backbone class arrows - participations and actRelationships are arrows that are directional have attributes rather than being lines that connect classes like in UML entry points - HL7 DMIMs and RMIMs have entry points (boxes with arrow pointing to a class); DMIMs can have more than one, RMIMs can only have one RMIMs are directional - all associations flow out from the entry point toward the remaining parts of the message labeling - HL7 diagrams are a little different in how they label associations (only on distal end, not bi-directional)
• #26: Hierarchal Message Definitions (HMDs) is a serialize version of the RIM in a specific order
• #27: The XML elements and attributes in a message instance correspond one-to-one with individual rows in the HMD. The names of the XML elements and attributes are taken from the "element name" column of the HMD.
• #29: Structural attributes Structural attributes are used to specify more precisely what each RIM class means when used in a message. For example , Act has a class code. The class code states what sort of Act this is, such as an observation, an encounter, or the administration of a drug. Mood is analogous to the tense of a verb. 
• #31: Coded Values HL7 uses two main types of code. The first type covers the specialized codes used for structural attributes and are defined by HL7 itself. The second type covers externally defined terms and codes such as SNOMED CT (Clinical Terms). Vocabulary Vocabulary is the set of allowed values for a coded field. All attributes with a code data type will have a vocabulary assigned to them. The ‘code system’ must be identified for any coded value in a message. NameTypeDescription Code= The plain code symbol defined by the code system. For example, "784.0" is the code symbol of the ICD-9 code "784.0" for headache. codeSystem= Specifies the code system that defines the code. codeSystemName= A common name of the coding system. codeSystemVersion= A version descriptor defined specifically for the given code system. displayName= A name or title for the code, under which the sending system shows the code value to its users. .
• #32: Coded Values HL7 uses two main types of code. The first type covers the specialized codes used for structural attributes and are defined by HL7 itself. The second type covers externally defined terms and codes such as SNOMED CT (Clinical Terms). Vocabulary Vocabulary is the set of allowed values for a coded field. All attributes with a code data type will have a vocabulary assigned to them. The ‘code system’ must be identified for any coded value in a message. NameTypeDescription Code= The plain code symbol defined by the code system. For example, "784.0" is the code symbol of the ICD-9 code "784.0" for headache. codeSystem= Specifies the code system that defines the code. codeSystemName= A common name of the coding system. codeSystemVersion= A version descriptor defined specifically for the given code system. displayName= A name or title for the code, under which the sending system shows the code value to its users. .
• #36: Speed Real-time on read requests: response time under 2 seconds Near real-time on updates Legal Assumption - Exchanges of clinical patient information between systems will be achievable at reasonable speeds while applying consent policies as part of privacy and confidentiality rules and regulations Scalable From growth in number of source systems From growth in point-of-care usage From growth in territory coverage From growth in surveillance usage From growth in administrative usage Reliable (High Availability) Redundancy: Power, Network, Servers (Application & Database), Disks Healthy economic balance in HIS vendor industry It is possible to maintain healthy business dynamics in the HIS vendor industry while insuring the uptake of a central source of EHR data in all provinces;