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HL7 Interfaces and Mobile Devices

If you have a medical application that interacts with mobile devices, and you want to modify this application to add an interface that reads or generates HL7 messages, you should note that an HL7 interface should not be contained on a mobile device.

There are many reasons for this:

• HL7 interfaces need to be persistent: HL7 interfaces are normally point-to-point interfaces that process persistent streams of data, such as Admit Discharge Transfer (ADT) events or lab results. An HL7 interface is a back-end datacenter server-to-server protocol that normally consists of interface engines that are monitored by hospital IT staff. When an interface goes down, alerts are raised until the interface is brought back up.
• Configuration and change management: HL7 interfaces are usually interactions between applications created by multiple vendors, not interactions that are contained within a single vendor's application. When a vendor's system is upgraded, the HL7 interface often needs to be modified to preserve the integrity of the medical data that is being processed. If the HL7 configuration is centralized, this modification is easy to perform. If the configuration is spread across a large number of user devices, modification becomes a nightmare.
• Licensing concerns: Many prominent HIS vendors charge substantial fees for each HL7 connection - in many cases, a minimum of $10,000 per interface. This means that server-to-server HL7 interfaces are more cost-effective.
• Database and storage issues: Many HL7 interfaces, such as ADT feeds, consist of broadcast streams of data. These streams of data need to be stored in persistent databases so that patient demographic information can be obtained. These databases cannot be stored on mobile devices: such devices are not always activated, and their storage capacity is too limited to contain large persistent databases.

The typical solution implemented by most vendors that use hand-held devices for medical applications is shown in the diagram below:

A Typical Hand-Held Device Solution

In this solution:

• A server containing an SQL database is deployed on a server.
• An HL7 interface, such as Iguana, sends HL7 messages to the database and receives messages from it.
• The HL7 messages are sent to mobile devices using the appropriate proprietary synchronization protocol.