Supporting Information Management for Regional Health Information Systems by Models with Communication Path Analysis

Supporting Information Management for Regional Health Information Systems by Models with Communication Path Analysis Alfred Winter, Birgit Brigl, Oliver Heller, Ulrike Mueller, Alexander Struebing, Thomas Wendt Institute for Medical Informatics, Statistics und Epidemiology, Leipzig University, Leipzig, Germany [email protected] Abstract The focus in healthcare has been changed from isolated procedures in a single healthcare institution to the patientoriented care process spreading over institutional boundaries. So interest shifts from hospital information systems (HIS) to regional health information systems (rHIS). More than with HIS an rHIS needs systematic information management. We present the 3LGM² meta-model and the corresponding 3LGM² tool to support information managers in health care regions. Every sequence of enterprise function, i.e. an information process, needs certain communication paths between those application components supporting the functions. The search for appropriate communication paths within a rHIS model is interpreted as allpairs shortest-paths problem which is solved using the Floyd-Warshall algorithm. Method and tool has been applied successfully in the setting of the SAXTELEMED project in Saxony, Germany.

1.

Objective: Information Management in Regional Health Information Systems

In many countries, especially developing countries, the driving force for healthcare has recently been the trend towards a better coordination of care. The focus has been changed from isolated procedures in a single healthcare institution (e.g. a hospital or a general practice) to the patient-oriented care process spreading over institutional boundaries. This should lead to a shift towards better integrated and shared care. Health care providers and health care professionals in a region - and in many cases even worldwide – have to cooperate in order to achieve health for the patient. [11] The hospital’s system for communicating and processing information, i.e. the hospital information system (HIS), is that socio-technical subsystem of a hospital which presents information at the right time, in the right place to the right people [2, 13]. Consequently the heterogeneity of a hospital is reflected by its HIS. The HIS has to be actively

designed and constructed like a (complex of) building(s) out of different and probably heterogeneous bricks and components. This needs systematic information management and like an architect the hospital’s information manager needs a blueprint or model for the hospital’s information system architecture respectively the hospital’s enterprise architecture [4, 7, 9]. Widening the scope to the healthcare region and the necessity for regional and worldwide cooperation of health care professionals and institutions, we have to claim for the respective cooperation of institutional information systems, e.g. hospital information systems. They shall form again an integrated information system, i.e. the regional health information system (rHIS). Thus the rHIS among others consists of all the components of the included hospital information systems. Since the complexity of an rHIS is something like the product of the complexity of the included hospital information systems, there is an even stronger demand for systematic information management in the region and for an appropriate model of the rHIS [13]. Cooperation in an rHIS depends on the availability of adequate communication links between the institutional information systems and their components. Besides technical problems of communication links there are a lot of complex problems of connecting heterogeneous software components of different vendors and with different database schemata to be solved. Especially the application of communication standards like HL7 and DICOM [1, 5, 6] needs proper planning and supervision as part of information management. The aim of the paper is x to shortly introduce the meta-model 3LGM² and the 3LGM² tool for modeling information systems in general and especially rHIS; x to illustrate, how the 3LGM² tool can be used to model the current or planned status of an rHIS; x to illustrate, how an rHIS model can be analyzed using path algorithms implemented in the 3LGM² tool.

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2.

Three Layer Graph Based Meta-Model 3LGM²

In [12] we proposed the three layer graph-based meta model (3LGM2) as a meta model for modeling HIS. 3LGM2 has been designed to support the hospital information management in its enterprise architecture planning (EAP) (see e.g. [9, 14]) activities. Accordingly, it distinguishes three layers of information systems, which especially provide a framework for describing both information processes at the domain layer and communication paths between application components and their interdependencies. 3LGM2 is defined using the Unified Modeling Language (UML).

2.1. Basic Concepts The domain layer of 3LGM2 describes a hospital independently of its implementation by its enterprise functions. Enterprise functions need information of a certain type about physical or virtual things of the hospital. These types of information are represented as entity types. The access of an enterprise function to an entity type can be in a using or an updating manner (see figure 1). Legend: ABC DEF

Enterprise function “ABC” entity type “DEF” function uses entity type function updates entity type

Legend: GHI

Application component “GHI”

component interface

communication link from a sender to a reciever Application components positioned on each other are indicating a “part-of”-relationship

Figure 2. Example of a logical tool layer (detail) (Names of application components are in German)

Figure 1. Example of a domain layer (detail)

The logical tool layer (see figure 2) concentrates on application components supporting enterprise functions. Application components are responsible for the processing, storage and transportation of data representing entity types. Application components may have a local database to store data. Component interfaces ensure the communication among application components. A component interface can receive or send messages of a certain message type. A message type transports (a) certain entity type(s). For the communication among application components communication links can be defined as relations between two communication interfaces, one being the sender of a message, the other one being the receiver. Each communication link is described by the message types which in fact are communicated.

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The physical tool layer consists of physical data processing components (like personal computers, servers, switches, routers, etc), which are physically connected via data transmission connections (e.g. data wires). Between concepts of the different layers there exist socalled interlayer relationships, which enable to describe the dependencies between model elements belonging to different layers. In this paper, the following interlayer relationships are of special interest: x An enterprise function is supported by a set of application components. x An Entity type can logically be represented by a dataset type or a message type to describe how it is stored and communicated. Dataset types describe what information is stored in a database, message types describe what information is transported by a communication link between two application components. A comprehensive UML-based description of the 3LGM2 can be found in [12].

driven interdependencies between enterprise functions. Other events like the availability of physical resources or the termination of activities are not considered here. Looking at 3LGM2, an information process describes dynamical aspects of the domain layer.

2.2. Information processes and communication paths To plan hospital information systems it is important to represent information-processing aspects of information processes as well as the consequences on the communication between supporting application systems.

Figure 4. Elementary example of a 3LGM2 communication path (Names of application components are in German)

Figure 3. Elementary example of a 3LGM2 information process

As presented in [3] we define an information process as a linear sequence of enterprise functions. This definition restricts the common interpretation of the concept 'business process' as we just look at the information processing aspects of enterprise functions as well as information

At this point we deliberately restrict us to rather elementary information processes to reduce the complexity at the logical tool layer. If we want to examine more complex information processes we just have to decompose them in to simpler ones. Figure 3 shows an elementary example of a 3LGM2 information process: “Radiological Imaging” produces entities of type “radiological image” which in sequence are used by the function “Radiological report writing”. We refer to a communication path as a sequence of communication links between application components necessary to satisfy the information needs given by a certain information process. Looking at 3LGM2 a communication path describes dynamical aspects of the logical tool layer. A 3LGM2 communication path consists of a sequence of communication links and the appertaining application

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components and their component interfaces. Within the sequence, a communication link may occur multiple times. The following additional constraint has to be obtained: For each pair of communication links cl1, cl2 where cl1 is the direct predecessor of cl2, the sender of cl1 must be possessed by the same application component as the receiver of cl2. This condition ensures that there is also a sequence of communicating application components. Figure 4 shows an elementary example of a communication path: In a certain hospital named “Zeisigwaldklinikum Bethanien” “radiological images” are transported from the radiological modalities (“02-Modalitäten”) to the picture archiving and communication system (“02-PACS”) and from there to a diagnosing support system (“02Befundungssystem”). Given a particular information process as e.g. in figure 3, all fitting communication paths can be calculated automatically. The path in figure 4 is one of those paths, fitting to the information process in figure 3. But the respective algorithm needs some information, which has to be documented in the model before: x for every function (e.g. radiological imaging): what application components are used for the function in the respective organizational units (e.g. in the hospital named “Zeisigwaldklinikum Bethanien” certain radiological modalities (“02-Modalitäten”) are used);

Figure 5. The 3LGM2 tool

x for every entity type (e.g. radiological image): what message types transport entities of that type and what communication interface is able to receive or send messages of that message type. The search for communication paths within a HIS model belonging to a given information process is interpreted as all-pairs shortest-paths problem. To solve this problem the Floyd-Warshall algorithm has been applied [3]. For every combination of organizational units, this algorithm finds out, what communication paths are possible. Figure 4 shows one of those paths, which in this case is located entirely within a single hospital.

3.

The 3LGM2 tool

The meta model has been supplemented by the 3LGM² tool [10]. Using 3LGM² as the ontological basis this tool enables information managers to graphically design even complex HIS. It assists information managers similarly to computer aided design tools (CAD) supporting architects. The tool provides means for analyzing a HIS or an rHIS model and thus for assessing the rHIS’s quality.

3.1. General Features The 3LGM² tool is a software product designed to create information system models on the basis of 3LGM² (Figure 5). On the modeling canvas, which dominates the main window of the tool, an information system can be modeled and displayed on three layers. A model diagram is a graph, i. e. consists of nodes and edges. There are different node types corresponding to the element classes defined in the 3LGM² as mentioned before. x On the top layer – the domain layer – the hospital’s enterprise functions and entity types used by these functions are displayed. x The middle layer – the logical tool layer – contains application components, database systems, document collections, component interfaces and communication links between them. Application com-

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1

3 2

4

Figure 6. Example of analysis

ponents support functions and store data about entity types in database systems. These relations are modeled explicitly by linking elements from the logical tool layer to elements of the domain layer and can be displayed as interlayer relationships like in figure 5. x The bottom layer – the physical tool layer – contains the physical tools: record shelves, computers, network components and even personnel, i. e. ‘touchable’ components of the information systems. Physical data processing components are the basis for application components. Similar to the relations between the domain layer and the logical tool layer, relations between the latter and the physical tool layer are modeled explicitly by linking model elements. Each of the element classes function, entity type, application component, database system, document collection, component interface, and physical data processing component is visualized in the model diagram and has a default geometric shape and a default background color. Since a fixed mapping of shapes and colors to the element types may be too inflexible, users can

x change the default mapping from element classes to shapes and colors, x change the shape and the color of selected elements, x assign bitmap symbols to selected elements, and x change the line style and the color of selected edges. The three different layers can be viewed and edited separately but can also be combined in a multi-layer view as shown in figure 5. Thus, users may focus on a specific layer but also on relations between the different layers. This feature makes it easier to create an integrated model and present this model to partners. The angle of and the space between the layers in the multi-layer view can be adjusted. Similar to a lot of other graphical modeling tools the 3LGM² tool also offers x typical operations for graphical modeling, e. g. aligning elements, moving elements up and down, changing colors and fonts, adding icons, etc., x a model browser for hierarchical browsing through the

model structure; x dialog windows to enter and view detailed information about model elements; x a menu bar and tool bars for accessing common operations.

3.2 Extraction of submodels Models especially of rHIS tend to be rather complex. Depending on the complexity and the required level of detail the model diagram may easily get unclear and confusing. The 3LGM² includes the functionality to extract subsets of models into submodels. Submodels are presented in separate diagrams, have their own model browser trees and hold own layout data, e. g. element position and colors. But the data elements from the underlying model are not separated, i. e. a change of an element name in a submodel affects the whole model. In figure 5 the submodel of those hospitals with their HISs and the respective inner components are presented, which took part in a particular project headed by

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the main hospital in the city of “Chemnitz” in southern Saxony.

3.3. Analyzing models The 3LGM² tool provides a set of predefined analysis functions. These functions are designed to answer specific questions arising in information management business. The result of an analysis can be highlighted in the model graphic but also be used to create a submodel. The analysis feature applies search algorithms on the internal graph structure to find model subsets and paths between model elements. It takes into account x names and descriptions, x element classes, and x connections to elements of specific classes. This feature may be considered as the major criteria of differentiation from other graphic and modeling tools. In addition to the predefined function set the user may define customized analysis functions in the analysis definition dialog. Figure 6 illustrates an example in which one of the functions ((1) “radiological report writing”) has been selected to find out, what application components in the different hospitals are used to support the function. The respective analysis in the repository highlights the application components found: (2) “05-RIS”, the radiological information system (RIS) of the hospital in the city of Stollberg; (3) “03-RIS”, the corresponding RIS in the city of Rabenstein and (4) the diagnosing support system in the city of Annaberg. A double-click onto the symbols of the application components would lead to more detailed information like e.g. the software products used and their vendors.

3.4 Exporting Bitmap representations of model diagrams can be created via an export operation. This feature makes it easy to embed model graphics into slides or report documents. A report feature to create text lists and tables is provided: Since the model files are saved in XML format, we integrated an XSLT processor to apply XSL transformations to 3LGM² models. The list of extractable information is under continuous development.

4.

Modeling The Regional Health Information System of Saxony

Since from the information management point of view an rHIS differs from an HIS in complexity but not in its fundamentals we decided to apply 3LGM², the 3LGM² tool, and the methods for analysis of information processes to the regional health information system of Saxony, a

federal state of Germany. The rHIS of Saxony has been further developed by the SAXTELEMED project, funded by the Saxonian ministry of health [8]. The project focused mainly on the exchange of radiological images and intended to improve integration of ambulatory and inpatient care. All examples and figures in this paper have been taken from this model.

4.1. Aim of the Model Since the author of this paper is a reviewer for telemedical projects under the direction of the Saxonian ministry of health, among others the model was designed to give answers to the following questions: 1. Every hospital applying for funding uses a particular method to describe their planned components and the components’ integration into the rHIS. How can the applications be made comparable? 2. Given, hospital A wants to introduce a certain application component for radiological imaging, i.e. a radiological modality, e.g. an MRT scanner system. Are there already other modalities in other hospitals? 3. Is it already possible to transport images from hospital B to C?

4.2. Modeling Procedure Final reports about the results of their projects out of 14 institutions (hospitals and practices) taking part in SAXTELEMED have been evaluated and used as basis for the 3LGM² based model of the Saxonian rHIS.

4.3. Results A model of that part of the Saxonian rHIS concerning the collaboration in the field of radiology and focusing on the exchange of medical images has been realized. The model describes the application components in 14 different institutions used for archiving and communication of images and for using the images for therapy planning. It also shows the integration of these components with administrative components as for example patient management systems. The communication standards and the respective message types are documented for all interfaces. Concerning question 1 it can be seen in figure 7, that the model leads to a homogenous depiction of the hospitals’ information systems with their parts as part of the regional health information system. The HIS of each hospital is considered to be an application component (white colored in the figure) of the rHIS; the application components are positioned onto their respective HIS.

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Figure 7. Part of the HISs and application components of the Saxonian rHIS

Question 2 can be answered by selecting the function “radiological imaging” on the domain layer and then using the analysis tool explained in 3.3.; the result is also shown in figure 7: all modalities and e.g. ultrasonic devices are highlighted. To find an answer for question 3 the information process of figure 3 should be taken as a basis for communication path analysis. This reflects the clinical situation that report writing needs images, which have been produced before. Figure 8 shows a calculated communication path, if for B the hospital of Rabenstein City and for C the hospital of Bethanien City is taken. The algorithm found, that images from the modalities in Rabenstein can be sent to the diagnosing system in Bethanien.

5.

Conclusions and discussion

Information management in health care regions should be and can be supported by dedicated modeling methods and tools coming from hospital information management. The 3LGM² tool with its means for analyzing information processes and related communication paths is suitable to support in documenting and planning an rHIS and to illustrate its capabilities. The 3LGM² based model of the Saxonian rHIS also helps experts in the Saxonian ministry of health to judge further funding applications for projects in the field of telemedicine. Experiences in Saxony show, that the application of our approach only makes sense, if there is an institution in the region, which feels responsible for information management from a regional perspective. This institution could be a ministry for health or another health care body. Without such an institution a systematic planning and developing of an rHIS is impossible – and our approach is not needed.

Figure 8. communication path in the Saxonian rHIS

6.

References

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