Many clinical applications throughout the institution will maintain their own data. In order to achieve consistency of data throughout the enterprise, it is necessary to propagate transactions that occur in one system to the other systems that maintain such data. Within the hub, the Routing layer is provided to make copies of certain messages, and send these messages to specified target systems. The routing function is driven by tables that indicate which messages needed to be copied, based on criteria such the patient identifier, location of a patient, type of message, etc.
For example, A message containing laboratory data is propagated to an ICU system which needs up to date information
about those patients assigned to ICU beds, and also to a research database, which is collecting lab data for all
patients.