Application of ESB in the medical industry

The ability of medical and health institutions to share clinical and medical health information is one of the main challenges facing the medical industry today, because the existing application systems of medical institutions adopt different standards, data models, or platforms, specific connections are often implemented based on specific needs when data sharing is required, due to the diversity of systems and the change and increase of integration requirements, this point-to-point information exchange mode becomes increasingly complex and difficult to maintain, and gradually cannot meet the increasingly complex data sharing and exchange requirements, existing system integration and integration require a unified application architecture to solve the above challenges, thus forming an interconnected medical and health service collaboration network, to enable citizens Community Sharing and exchange of medical materials between centers, between community centers and community centers.
Concepts of Enterprise Service Bus:
In the Service-Oriented Architecture (SOA), enterprise service bus (ESB) is an important technical architecture for integrating and interworking between systems, it provides an advanced application integration concept based on the enterprise bus to minimize the complexity of application system interconnection and reduce integration and maintenance costs. In the Regional Health Information Integration Environment, building a Unified Enterprise Service Bus is an important means to achieve multi-system integration in the regional health information network. Here, we call the specific implementation of the Enterprise Service Bus in the healthcare industry as the Health Service Bus (HSB ). While implementing the basic features of the Enterprise Service Bus, such as message conversion, routing, and Protocol access, the Health Service Bus must also meet specific needs in the medical and health industry, such as patient privacy protection and medical and health industry standard support.
Overall Health Service Bus Architecture:
Combined with ESB technology-specific, IBM-related software The reference architecture diagram of the Health Service Bus HSB is provided, which is based on the bus implementation platform of IBM WebSphere Message Broker, the HSB part includes
Healthcare Provider applications: Point of service (POS), including his, EMR, CIS, and Lis, which can be directly connected to HSB, you can also access HSB with the help of an adapter.
Access channel integration: medical practitioners, patients, and management personnel can access background systems through multiple channels, such as portal and mobile Devices.
Application Platform: A medical application platform, such as two-way referral, remote consultation, process, and Collaboration applications, can be connected to HSB.

The following sections of HSB include the home democracy index, ehr data service, and ehr Analysis Service, which are explained in detail in this series of articles and will not be explained here.
The IBM WebSphere Message Broker (WMB) product provides a platform for implementing the Enterprise Service Bus. Combined with the powerful integration functions provided by WMB, HSB can provide
Routing: the requested message can be automatically routed to the corresponding background service based on the message content, without the need to specify the endpoint address. By integrating wsrr (WebSphere service registry and repository) WMB dynamic routing can be implemented.
Conversion: the message conversion function is an important capability provided by HSB. If the request message does not meet the format requirements of the target service, HSB can use the built-in nodes provided by WMB, such as compute, transform, and mapping, to convert the Message format. Common message exchange standards in the healthcare industry are HL7 messages, by integrating the conversion engine wtx (WebSphere transformation Extender) and wtx HL7 pack, HSB supports parsing and conversion of HL7, especially messages in HL7 v2.x format.
Protocol binding: HL7 is generally transmitted using the mllp (minimal lower layer protocol) protocol. HSB can be configured using the built-in TCPIP to support mllp protocol access, it also supports common transmission protocols and data protocols such as soap, XML, and HTTP.
Publishing/subscription: publishing/subscription is an asynchronous message transmission mechanism. It defines the application model to publish the message publisher (publisher) in a loosely coupled manner) it is associated with the subscriber of the message. Healthcare organizations that participate in the publish/subscribe model can define topics to publish patient medical events to HSB, while HSB can publish medical events to subscribers that subscribe to the topics. For example, after a patient is discharged from the hospital, the discharge event can be published to HSB, and the community center subscribed to the event can arrange community doctors to follow up the patient after receiving the incident.
Service combination: Service requests may involve multiple service providers. HSB can combine multiple service providers to implement a short process to meet more complex requirements.
Secure Gateway: uses SSL and other technologies to ensure secure transmission of channels. It integrates TDS (Tivoli Directory Server) and tspm (Tivoli Security Policy Manager) implements identity authentication and privacy protection for the requesting user.
In the following sections, We will detail the integration of other products to implement some specific features of HSB.
Integrate wtx to convert HL7 messages
HL7 is a common exchange standard in the healthcare industry, including HL7 v2.x and V3 versions. Due to its early launch of HL7 v.2x, HL7 is widely used. HL7 V3 is a standard XML format, which can be easily supported by WMB. In version 2.x, data in HL7 is composed of messages. A message consists of multiple segments (segments) and one segment consists of multiple fields (fields, A field is a string consisting of one or more data elements.
Because HL7 v2.x is a special linear format, it is not as convenient for parsing and conversion as XML. IBM WebSphere transformation extender (wtx) and HL7 pack provide comprehensive support for HL7 message processing. WMB also provides built-in wtx map nodes for direct integration with wtx, this makes it easy for HSB to process HL7 messages.
Integrate TDS and tspm to provide security gateway
IBM Tivoli Directory Server (TDS) provides a powerful Lightweight Directory Access Protocol (LDAP) identity infrastructure, the application system connected to HSB can register the user identities of patients and doctors to the TDS for unified management. during runtime, WMB and TDS are integrated to authenticate the requested user, the authentication method can be a simple user name/password method, or a safer authentication structure based on digital certificates. The specific authentication process can be performed by WMB, HSB developers only need to configure the connection parameters in WMB. Figure 2 shows an example of how to configure a connection to TDS in WMB toolkit.
Figure 2. Configure security profile in WMB to integrate TDS

A typical example of requesting user authentication is that a doctor uses a hospital application system to access a patient's medical record document, and the application system uses the standard message xds querydocument (SOAP format) defined by IHE) request the ehr data service through HSB. After receiving the SOAP request, WMB extracts the request username and password from the SOAP header and uses LDAP for verification, the ehr service can be called only when the verification is passed.
HSB authenticates a user's identity as the first step of the security gateway. After Authentication, it also needs to determine whether the user has the permission to call the service and access certain resources. You need to support more complex authorization rules for viewing, submitting, or modifying medical documentation. For example, authorize a user to only have the permission to view a specific document of a patient or even some specific content of a document, to better protect patient privacy.
Extensible Access Control Markup Language (XACML) is an XML-based open standard language developed by Oasis. It proposes a general access control policy language and a framework for executing authorization policies. The IBM tspm (Tivoli Security Policy Manager) Product supports the XACML language to define the Authorization Policy Model for permission management of different roles. In HSB, we use WMB to integrate tspm to support runtime decision-making permissions, so as to ensure that the patient's privacy is maintained while sharing the patient's electronic health information. For details, refer to the series of permission management services developed based on Tivoli Security Policy Manager.
Integrate medical service provider applications using adapters
The application of medical service providers is developed by various suppliers. The development platforms, technologies, and interfaces of different suppliers are different. To facilitate the application of medical service providers to access HSB and minimize the cost of restructuring existing systems, it is a good way to develop and deploy corresponding adapters to various medical institutions, the adapter can pass in a specific request from the provider application and convert it to the Message Type required by HSB, such as HL7 and IHE xds, the adapter can have multiple types based on the source data and target data to be adapted:
Mllp (minimal Lower Layer Protocol) is the most common message transmission method used to transmit HL7 messages. The mllp adapter can encapsulate the received messages into mllp messages and connect them to HSB through the mllp transmission channel.
The file adapter supports the submission of CDA files. The CDA file can be placed in a folder. The file adapter periodically detects and constructs an Ihe provider & registerdocument request to send it to the ehr data service through HSB.
The Ihe adapter is developed based on the Open Source Tool OHT (open health tooling) Ihe. It provides two methods: API and Web Service Interface, help the provider application system construct the Ihe request message in the form of an Ihe client. For example, if you call the EMPI system, the Ihe adapter can construct the request data of the application system into a standard message format that complies with Ihe pix/PDQ. If you call the ehr data service, the Ihe adapter can construct the request data of the application system to conform to the standard message format of Ihe xds.
Using adapters can reduce business application-side programming caused by different development Architectures Complexity: it allows medical service providers to quickly access HSB to ensure secure and reliable message transmission. It also supports traffic control, log recording, localization and customization.
Integrate wsrr to provide service management
In the regional health care solution, the systems connected to HSB for Electronic Health Information Sharing include application systems of various medical institutions, ehr systems, and EMPI, these systems provide external interfaces in the form of services and describe interfaces in the most common WSDL mode. As the registry and repository of service metadata, wsrr (WebSphere service registry and repository) establishes a central location for searching and Managing Service metadata obtained from multiple sources, such as the service endpoint address, service description, and policy life. Wsrr can help business analysts, solution architects, and developers better manage and maintain these services, fully explore the business value of SOA, and implement SOA governance functions.
During the HSB operation, WMB can be integrated with wsrr, and the service endpoint address can be dynamically selected based on the service metadata, thus improving the application flexibility of Enterprise Service Bus integration. If the endpoint address of the target service changes, wsrr allows administrators to update service metadata to dynamically control the routing and conversion of WMB message streams. Since v6.1, WMB provides two new nodes, registry lookup and Endpoint lookup, integrated with wsrr, to support retrieval of service endpoint addresses.
Summary
This article first introduces the requirements for system integration in the regional medical information network, and introduces the Health Service Bus HSB, then, the overall reference architecture and various functional components of the health service bus are introduced in detail, and the integration of WMB with other products to implement the health service bus is described in detail.