...
Alternatively, a back-end service could use a polling strategy to determine when any changes have occurred to the FHIR resources (for example, from an external data feed). This back-end service would then submit the resource to the messaging system for routing.
Bilirubin Monitor Application Usage of the Reference Messaging System
The Bilirubin Monitor application is a backend service application that is deployed external to the EHR, that is pre-authorized with the EHR according to the SMART on FHIR specification and OAuth 2.0/OpenID Connect technologies. The Bilirubin Monitor is send message from the reference messaging system according to subscription resources that have been registered with the messaging system. A message send from the EHR to the Bilirubin Monitor should not include full resource information. Instead the Bilirubin Monitor should query any resource information to comply with the SMART on FHIR security protocols.
...