2007 Joint Workshop on High Confidence Medical Devices, Software, and Systems and Medical Device Plug-and-Play
Interoperability
Towards a Service-Oriented Architecture for Interconnecting Medical Devices and Applications M. Strähle", M. Ehlbeck#, V. Prapavat", K. Kück*, F. Pranz", i.-u Meyer" *DrägerwerkAG, Lübeck, Germany, # Dräger MedicalAG, Lübeck, Germany joerg-uwe.
[email protected]
Abstract
open platform standards aim to handle heterogeneous systems and applications with a high degree of scalability and flexibility.
A technical concept has been developed which employs a service-oriented architecture (SOA) as an IT platform and ecosystem to handle different modalities, devices, and data streams in the OR. A SOA ecosystem is deployed to interconnect modalities of an anesthesia workplace and an endoscopic surgery worl..tplace with a hospital information system. The integration of the anesthesia cockpit into a SOA based network is achieved with a disparate Web Application Server. This server physically connects to the data ports of the anesthesia unit and transforms ventilation and hemodynamic data into Web Services. The implemented Web Services for hemodynamic and respiration data are using an XML vocabulary that is predominantly takenfrom the ISO/IEEE 11073-10201 standard. Implemented Web Services rely on an adapted and standardized domain information model that forms the basis for the representation of medical device and vital signs semantics. Forthcoming research ejJorts will be directed towards an enhanced SOA based registry and repository that includes governance and policies of Web Services that are generated by networked medical systems.
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Figure 1. Messaging and service exchange in a SOA Illustration of standardized messaging and exchange of Web Services between a service provider, a service consumer, and a directory (UDDI registry). Commonly, SOA deploy Web Service (WS) standards for messaging (SOAP), the definition of Web Services (WSDL), and the registration procedures for universal discovery, description, and integration (UDDI) of WS
1. Introduction The German 'OR of the future' projectFUSION is aiming to develop tomorrow's patient-tailored precision tools to assist navigation during soft tissue surgery [1]. A technical concept has been developed which employs a service-oriented architecture (SOA) as an IT platform to handle different modalities, devices, and data strearns in the OR. SOA is a software architecture made up of components and interconnections that stress interoperability and Iocation transparency. A SOA-type software relies on standardization efforts of independent organizations, e.g., the World Wide Web Consortium (W3C) [2]and the Organization for the Advancement of Structured Information Standards (OASIS) [3]. The emerging
2. SOA for networked medical devices SOA type IT platforrns are emerging as solutions for clinical enterprises. An Enterprise Service Bus (ESB) is providing a common data-centric middleware structure for reliable transport and traceability of synchronous and asynchronous messages and XMLbased Web Services [4]. A comprehensive XML vocabulary for medical application is not yet available. Medical vocabulary in this project relies on existing vocabulary which is defined in standards as HL7, DICOM, and ISO 11073-x for device connectivity, The schematic below illustrates how medical devices
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0-7695-3081-8/07 $25.00 © 2007 IEEE DOI 10.1109IHCMDSS-MDPnP.2007.27
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Figure 2. SOA based network of medical devices Hypothetic configuration of a SOA with networked medical devices and services. In this example, Service 7 is consuming the Portal 1 service and Services 1; 3; 4.
Figure 3. SOA based orchestration of encapsulated applications Encapsulated applications of three different vendors are orchestrated in a SOA to provide data and modallties at front-ends (surgical cockpit, anesthesia cockpit) or to a clinical database
3. Implementation of SOA in the OR A SOA approach is deployed to interconnect modalities of an anesthesia workplace (ZEUS ®, Dräger Medical) and an endoscopic surgery workplace (ORI ® KarlStorz) with a hospital information system (Siemens Medical Solution), as depicted in Figure 3.
The anesthesia workplace is serving as a cockpit that integrates components and displays for delivering intravenous and volatile anesthetics with a unit for monitoring of hemodynamic parameters as heart rate, blood pressure, respiration rate, ECG, and Sp02. In the present configuration, the anesthesia cockpit is considered a medically approved legacy device that is not desizned to deliver Web Services in a SOA environment. The integration of the anesthesia cockpit into a SOA based network is achieved with a disparate computer unit, termed Web Application Server (WAS). The WAS physically connects to the data ports of the anesthesia unit and transforms ventilation and hemodynamic data into Web Services. The system setup is depicted in the illustration ofFigure 4.
The FUSION research project deploys an integration server concept of a SOA middleware supplier (Inubit AG, IS Professional Edition) [5]. An Apache Tomcat Java environment is serving as a Servletengine. Web Services have been developed utilizing the C# programming language in a .NET framework. The implemented Web Services for 'hemodynamic and respiration data are using an XML vocabulary that is predominantly borrowed from the ISOlIEEE 11073-10201 standard.
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5.0utlook The OR Integration part of the FUSION research project 1S in its preliminary phase. Interoperability and interchange integrity of Web Services throughout the ESB based SOA still need to be tested under run-time conditions. Future SOA Policy issues comprise:
Figure4. Integration of legacy medical devices in network
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A Web application server has been implemented to convert data and modalities of an anesthesia machine and a hemodynamic unit into Web Services that are exchanged through an Enterprise Service Bus (ESB).
Implemented Web Services rely on an adapted domain information model that forms the basis for the representation of all medical device and vital signs semantics that communicate in this standard. The root ofthe used hierarchical object model includes different kind of devices, e.g., anesthesia devices, hemodynamic devices, or HIS devices. They serve as container for different device parameters. Channels are appended to the parameters. Channe1s contain the numerical values. Alarms and settings can be matched to any item in this object tree. Web Services may contain complete data sets or only sub sets for devices, parameters, and channels.
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[4] Web Services and Service-Oriented Architectures, Douglas K. Berry, Morgan Kaufmann Publishers, 2003. [5] www.inubit.com, Inubit AG, Berlin
: SOA govemance/ oouaes rar medical oevices: i . Rules an;! restri:::tkms enforc&d on Web Services i • Safety rssces ~ • Availabillty QuSlity or servi~s 1 • Semantic diaionaryJ . SW version information
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[I] www.somit-fusion.de. public research project funded by the Federal Ministry for Education and Research in Germany
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6. References
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FDA compliance is sought for a generic SOA based IT platform hosting networked medical devices and systems.
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Figure 5. Use of a Oomain Information Model (OlM) in a SOA
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