Layered Implementation View of a SOA Based Electronic Health Record

Interoperability between legacy systems has crucial importance for integration of many distributed systems. Within health information systems, the need for interoperability between legacy systems is well-known, as these are heterogeneous systems which have a long lifespan. An interesting example of health information systems is the Electronic Health Record (EHR), a virtual record of every health-related event, including hospital admission, general practitioner visit, exams, and allergies experienced by individuals over their lifespan from in uterus to death. A great challenge for implementing EHR applications is that these systems often have to integrate large amount of data gathered from legacy systems into a single application. This paper describes in detail the implementation view of a software architecture based on web services for developing an EHR application in a public hospital. The architecture has been defined with a layered style for implementation and on services identified within current legacy systems. Detailed explanation on the software development, including architectural elements and services catalog are described as well.