XPath-Based Filter for Publish/Subscribe in Healthcare Environments

In healthcare information exchange (HIE) environments, a publish/subscribe system for the selective and dynamic dissemination of information becomes more and more important due to increasing demand for timely and accurate data sharing among healthcare enterprises. Integrating the Healthcare Enterprise (IHE) proposes a general framework for defining publish/subscribe interactions, and a subscription mechanism using the framework. The mechanism relies on simple document metadata matching. However, in most HIE environments the data are disseminated in the format of XML documents. A more sophisticated filtering mechanism is expected to exploit the structure of the XML documents to perform more efficient and more accurate dissemination of information. We have developed an XPath-based filter for IHE XDS documents. In this paper, we describe the XML schema over which the XPath-based filter is constructed, and show the technical viability of XPath-based filter in the formulation of complex queries on the content and the structure of XDS documents.