Clinical implementation of the IHE presentation of grouped procedures integration profile-implementation details

University Hospitals Leuven, Dept. of Information Technology,Leuven, BelgiumKeywords IHE Telemedicine PACS eHealthPurposeWiththispresentation wewantto shareinitial experiencesin deployingIHE integration profiles, primarily XDS (Cross-Enterprise DocumentSharing)andXCA(CrossCommunityAccess).Thisispartofanationalproject in Belgium that aims at making medical history of a patientavailable to any physician who is currently in contact with that patient,regardless of which institution that information was collected in.In this project the medical documents typically remain at thesource (for example a hospital) but there is a system that allows tofind out which documents are available and to retrieve them. Thatsystem is implemented on two levels: regional partnerships betweenhealth care providers maintain an index of documents available withinthat hub, while a national metahub manages information about whichhubs have any data on a specific patient. Our hub will group around20 hospitals throughout the Flanders region.That national system is being developed around a Belgian standardfor medical communication, as that standard was already used in anumber of local initiatives. In our hub, in contrast, we have decided touse IHE profiles. We therefore must build bridges between the localstandard and IHE and match the concepts in IHE to the policies in thenational project. More in general, we study possibilities to advancethe use of IHE in a gradual fashion.MethodsDocument sharing within the hub is in principle based on the XDSprofile. In practice, however, current information systems in theconnecting hospitals do not provide an XDS interface. At the sametime we believe that the largest bottleneck in this project is exactly theeffort required to connect such local information systems. Commer-cial software has been identified that enables those systems to connectusing HL7 feeds.This solves some of the connectivity problems but not all. Alreadyin the local setting, connecting medical information systems is moreinvolved than just sending HL7; in an organization that extendsbeyond the own institution, complexity is even much higher. Forexample, at the time at which the information is generated the global(national) patient ID may not yet be known, or the patient may not yethave provided consent for data sharing. Handling such exceptionscould be rather difficult (e.g., putting data aside and implementing anexplicit trigger to transmit it later). Patient merges, which occur fre-quently in medical practice, can now be at the local as well as theglobal level. From experience in technical pilots we are now final-izing adaptations to the system that enable to concentrate most, if notall, of the complexity within the central software. The HL7 feeds fromthe local systems can take abstraction from these aspects, and localworkflows need only be adapted in minimal ways.We did not limit ourselves to the basic XDS profile. For example,we want to provide access to previous data right after consent hasbeen provided, but in the absence of such consent the XDS index maynot yet have been populated. A lot of consideration must go to pro-tection of personal data anyhow. We use a combination of XDS andXCA. The XCA profile was designed to exchange informationbetween loosely coupled domains. In our project we deploy XCA forits possibilities to query information dynamically (whereas XDSassumes that the index has been populated before). This makes ispossible to define a separate XDS domain for each hospital (in whicheven the index data is contained) while from the outside this looks asa single domain that always contains up to date information. Mostimportantly, this gives us more implementation options within the hubwhile still sticking to IHE profiles.By deploying the IHE PIX profile (Patient Identifier Cross Ref-erencing) the local systems can keep using local patient IDs. This isparticularly important for information feeds that the hospital does notwant to interfere with, such as DICOM communication with a PACS.ResultsThe system is still in technical pilot, internally as well as in con-nectivity to other (non IHE) hubs and the national metahub.As illustrated in Fig. 1, in the technical implementation we try to rig-orously stay with IHE profiles internally, even if the environment inwhich this system must operate is not particularly IHE friendly. Thebridgebetween thisIHEhubandtheotherhubsintheBelgianprojectisimplemented as an XCA responding and initiating gateway. For theconnecting systems, and for the interactive viewing software providedover the Internet, the other hubs therefore look like IHE hubs.Current work includes integrating the national concepts for userauthentication (in part based on the electronic ID card) and for securecommunication, and this in such a way that we can keep using com-mercial components that were developed in international competition.Fig. 1 The eHealth hub rigorously adheres to IHE profiles internally.Conversions to and from the national standard are concentrated in agateway that implements the IHE XCA profile. The informationsystems within the hospitals typically use HL7 feeds to providedocuments to the local repository that acts as an XDS results server