LinkEHR: A Platform for the Normalization of Legacy Clinical Data Based on Archetypes

2. Dual Model Ehr Architectures

During the last decade different organizations have been working on the definition of an EHR architecture for the faithful communication of health data. The Technical Committee 251 (health informatics) of the European Committee for Standardization (CEN/TC251) completed in 2007 a European Standard for the communication of the EHR called EN13606 whose part 1 (reference model) (International Organization for Standardization, 2008a) became an ISO standard in February 2008. One of the main contributions of CEN/ISO 13606 is the utilization of an EHR architecture based on the dual model methodology (Beale, 2002) for the description of the structure and semantics of health data. The dual model methodology distinguishes a reference model and archetypes. In a broad sense, a reference model is an abstract representation of the entities and relationships of a domain which is designed to provide a basis for the development of more concrete models and implementations. The reference model is represented by a stable and small object oriented model that models the generic and stable properties of health record information. The generality of the reference model is complemented by the particularity of archetypes. Archetypes are detailed and domain-specific definitions of clinical concepts (Apgar score, discharge report, primary care EHR, etc.) in the form of structured and constrained combinations of the entities of the reference model. Their principal purpose is to provide a powerful, reusable and interoperable way of managing the creation, description, validation and query of EHRs. From a data point of view, archetypes are a means for providing semantics to data instances that conform to some reference model by assuring that data obey a particular structure and satisfy a set of constraints. The semantic description of domain concepts is achieved by linking the data structures and content to knowledge resources such as terminologies and ontologies (Maldonado et al., 2009).