Intelligent eHealth solutions often demand patient data from different sources such as hospital, laboratory, and intensive care information systems or—out of performance or legal reasons—a strict separation of patient data gathering and intelligent processing is necessary. In these cases, Medexter’s Arden Syntax server, including its rule engine and its database connector, accesses a project-specific data warehouse (which can be quite general and extended). This data warehouse receives “raw” patient data through communication servers or import routines from any external data source (in HL7/XML/batch or other formats). The received data trigger the rule engine (when appropriate), and the data warehouse makes data available for further processing in the Arden Syntax server. The data warehouse can in return store the final or even the intermediate results generated by rule processing. These results may subsequently either be transferred back to the calling host application for presentation or—if the data warehouse is part of a separate solution—to the solution’s presentation layer. The stored results may be used for reporting and benchmarking, or for data and knowledge mining. By introducing such an architecture, autonomous add-on clinical decision support systems are established. An example is Medexter’s Moni system, which monitors and reports on hospital-acquired infections in intensive care units with adult and neonatal patients.