20 | 20 | The latter may be in the form of an existing PMI (patient master index) or other directory, or it may be in the form of an openEHR demographic repository. An openEHR demographic repository can act as a front end to an existing PMI or in its own right. Either way it performs two functions: standardisation of demographic information structures and versioning. An openEHR EHR contains references to entities in whichever demographic repository has been configured for use in the environment; the EHR can be configured to include either no demographic or some identifying data. One of the basic principles of openEHR is the complete separation of EHR and demographic information, such that an EHR taken in isolation contains little or no clue as to the identity of the patient it belongs to. The security benefits are described below. In more complete EHR systems, numerous other services (particularly security-related) would normally be deployed, as shown in FIGURE 7. |