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Defined within the Context Management Architecture (CMA) is the ability for applications to establish links based on clinical subjects with a common interest. These links allow applications to cooperate and maintain synchronization when the user changes values for one or more of the subjects of interest. The degree of synchronization is variable depending on the needs of the application.

• Applications can maintain a constant state of synchronization.
• Applications can be allowed to become unsynchronized and return to a synchronized state periodically.

Clinical links and the subjects that they represent are classified broadly as common or secure. Whether a link is common or secure is defined with in a subject's data definition.

A complete set of subject data definitions are specified in the document Health Level-Seven Standard Context Management Specification, Subject Data Definitions, Version CM-1.5. Following are the two core standard subjects to the CMA:

• Patient - enables the user to select a patient of interest in any linked application and automatically synchronize all the linked applications to the same patient. When an application implements linking using a Patient subject, it is a Patient Linked application.
• Users - enables the user to securely log on to any linked application and automatically synchronize all other linked applications to the same user. When an application implements linking using a User subject, it is a User Linked application.

The CMA standards allow custom subjects to be defined to create custom links between applications that are aware of the custom subject definitions.

While there can be multiple subjects (e.g. patient and user) within a common context system only one link coordinates the CMA compliant participants in the context session. When an application is linked, it will “tune” to all of the subjects it is capable of dealing with. For example:

• An application that is only Patient Link-enabled tunes to just the patient context.
• An application that is only User Link-enabled tunes to just the user context.
• An application that is both Patient Link-enabled and User Link-enabled tunes to both the patient context and the user context.

The time when a set of applications share a common context is known as a context session. It is possible for a single point-of-use device to host multiple context sessions, however only one session is active at a time. Applications are able to join active context sessions, but unable to join sessions that are inactive. All other context management functions are allowed. For example, applications may leave the session, and it is still possible for context change transactions to be performed on a deactivated session. This enables a single user to have multiple sessions, or enables multiple users to share a device and each have their own session.

Topics

Programming with CCOW

Implementing Common Contexts

CCOW Concepts