Interconnectivity of Cardiology Patient Databases using Internet Technology

PJ Lees, CE Chronaki, F Chiarugi, E Tsiknakis, SC Orphanoudakis

Center for Medical Informatics and Health Telematics Applications, ICS-FORTH, Heraklion, Greece

Abstract HYGEIAnet (http://www.hygeianet.gr), the regional

health-telematics network of Crete, interconnects healthcare facilities in the region, supporting the development of the regional healthcare information infrastructure. Middleware components of this infrastructure have been used to extend an earlier project that used Internet technology to provide secure multilingual access to medical records in a cardiology department. The resulting scalable and modular architecture can support interconnectivity between medical records of cardiology patients in departments within the same and different institutions.

1. Introduction Integrated regional healthcare networks are

increasingly used to facilitate the sharing of health data and medical expertise [1]. HYGEIAnet is a regional health telematics network currently being implemented on the island of Crete [2]. HYGEIAnet encompasses a wide variety of medical software applications, not limited to cardiology, and has the long-term objective to realize the concept of the Integrated Electronic Health Record (I-EHR) that will provide authorized users with access to the complete medical history of patients treated in the region. The I-EHR is supported by middleware services of the evolving Healthcare Information Infrastructure (HII), which facilitate the automatic collection and indexing of data regarding healthcare encounters of patients treated in the region. Alternative views of the I-EHR facilitate domain-specific presentation of medical data appropriate for different medical disciplines such as cardiology [3].

A separate, but related project within HYGEIAnet investigated the feasibility of using Internet technology to provide secure multilingual access to the medical records of a cardiology clinic [4-6]. The purpose of that project was twofold: to share data with other departments within the same institution and to allow physicians in other regions or countries to see the clinical data of patients of theirs who may have been treated here. The work presented in this paper attempts to move a step towards the I-EHR, allowing cardiologists to link medical records of the same patient in different departments of the same

or different hospitals in HYGEIAnet. Middleware services of the HII are used to discover compatible information systems and medical records of the same cardiology patient.

The rest of the paper is organized as follows: Section 2 presents HYGEIAnet, the regional health telematics network of Crete, focussing on the I-EHR project and related middleware services of the HII. Section 3 provides an overview of the earlier project that provided multilingual access to medical records of a cardiology clinic. Then, section 4 discusses the process of interconnecting cardiology medical records in different departments and reports on the project status and our future work. Finally, section 5 summarizes our work.

2. HYGEIAnet HYGEIAnet (Figure 1) is currently the point of

reference and also a long-term objective of the Center for Medical Informatics and Health Telematics Applications (CMI-HTA) of the Institute of Computer Science (ICS), Foundation for Research and Technology - Hellas (FORTH). It is the integrated health telematics network that is under development in Crete and is expected to serve as a model for national and transnational healthcare networks. Currently, the network interconnects 7 hospitals, 10 primary care centers, and several community doctors in the region of Crete.

Figure 1: HYGEIAnet, the Regional Health Telematics Network of Crete.

The development of an HII is considered as a necessary precondition for the development of a generic and evolving frame of reference for the reuse of services, components, and interfaces. In the development of the HII, HYGEIAnet follows the guidelines of the healthcare reference architecture presented in [1]. Users are primarily interested in information processing

applications, which they may own or gain access to as end-users via communications networks. These services are ‘enabled’ by other underlying, transparent services provided by information and network service providers. Applications and enabling services, in turn, employ certain information processing services and systems for data transport, which can be geographically distributed throughout the region. Thus, the reference architecture model refers to three basic components: applications, enabling (or middleware) services, and physical infrastructure (see Figure 2).

teleconsultation(application)

virtual EHR(application)

directory services

terminologyservices

messagingservices

resource services

securityservices ….application

cooperation

Figure 2: Key middleware services of the HII.

2.1. I-EHR In an increasingly mobile society, pieces of a person’s

health record are distributed in an increasing number of healthcare facilities in electronic or other form. Although each healthcare facility is autonomous, continuity of care requires that different healthcare facilities operate in a cooperative working environment. In this environment, diverse user groups require secure, customizable access and sharing of information residing at geographically distributed autonomous information systems. The goal of the I-EHR project [3] is to demonstrate a technological approach that will enable knowledge discovery in a regional health-telematics network such as HYGEIAnet. This can be achieved by defining all the middleware enabling services that are required for the provision of basic services in a consistent, reusable, and expandable way. This can be done by developing the necessary interfaces for accessing clinical information, and by implementing a number of interfaces adapted to the needs of a number of medical disciplines.

Components and services defined in the contents of the I-EHR project are middleware services of the HII. Some of these components have been reused to interconnect the medical records in cardiology and CCU departments across HYGEIAnet.

2.2. Middleware services In the context of the regional healthcare infrastructure,

generic and healthcare specific middleware services facilitate access to the HII through common components and standard interfaces.

Among the middleware services that support the development of the I-EHR are directory, security, and

terminology services. Directory services maintain information on healthcare professionals, patients, and information systems. For healthcare professionals, directory services typically provide information on contacts, roles, and authorities. In addition, the storage of public keys in the directory enables confidential and authenticated communication. The patient directory addresses one of the major obstacles in the design of the I-EHR, namely the absence of unique patient identification. This is due to the fact that organizations usually assign IDs that uniquely identify patients within their local domain of ID values. As a result, these ID values are meaningless outside these particular systems or organizations. The patient directory service correlates identifications of a patient in the information systems of HYGEIAnet, through his/her main identification attributes (i.e. lastName, firstName, parentName, birthDate, gender). Finally, the information systems directory is a registry of all information systems in HYGEIAnet. Standard protocols (LDAP) and interfaces in COM and CORBA provide access upon authorization to these directories.

Security and confidentiality services are based on a regional certification authority, which will provide digital certificates to healthcare facilities and human resources. The purpose of the certification authority is to certify the role and authority of the collaborators. The combination of digital signatures for authentication, public key cryptography for recipient authentication, and Secure Socket Layer (SSL) for secure data-transfer, provide the technological framework for the secure exchange of medical data [7,8]. Finally, terminology services facilitate translation between different terminology standards.

3. Cardiology information system A system that uses Internet technology to provide

secure remote access to the computerized medical records maintained in a Cardiology Department in a regional hospital was presented in [4-6].

Figure 3: Part of the patient confirmation screen

Authorized users obtain patient or user passwords to access the system. In the log-on page, the authorised user may select the language in which the subsequent data will be displayed. If a patient password is entered, the user is redirected to a patient confirmation page (see figure 3). This is the only time that the patient's name is transferred. Alternatively, if a user password is provided, then a patient must be selected first, based on a few letters of the first and last names. After a patient is selected, the user is redirected to the patient confirmation page.

Figure 4: Diagnostic report of an echocardiogram

The starting point for navigation through the patient's mini-Web is the demographics page, which includes a hyperlink to a page of risk factors for coronary artery disease and one or more hyperlinks to pages with data relating to the patient's admissions to the clinic. Admission pages include dates of admission and discharge, presenting symptoms, diagnoses, and medication. The admission page also includes hyperlinks to other pages with information about specific examinations, such as electrocardiograms, echo, stress, and laboratory findings (see figure 4). Images or other data files can be referenced from the relevant page by a hyperlink and viewed either within the browser window or by using suitable plug-in software.

3.1. Architecture of Web interface The web architecture consists of two components: a

database and a web server component. The web server component is configured to create upon request temporary “mini-Webs” containing the medical data of specific patients. These patient mini-Webs may be viewed using standard Internet browser software. Mini-webs are deleted when the user logs-out or during regular clean-up procedures.

The database component consists of scripts that read HTML templates line by line, as text files, insert data from the database, search for meta-statements and perform the necessary actions, add standard headers and, finally, write the completed page to the appropriate mini-Web location. The system maintains one set of HTML templates for each language supported. Which set of templates is used, depends on the language selected on the login page. In addition to the text and formatting instructions found in standard HTML files, the HTML templates contain delimited field names and commands from a simple meta-language. Each template is associated with a “root” table in the database, from which most or all of the data are extracted and inserted in positions

indicated by the relevant field names. Meta-statements indicate the insertion points for data from tables other than the form's “root” table or for hyperlinks to other mini-Web pages, details of image or other files that must be copied to the temporary mini-Web location, and so on.

Figure 5: Access to cardiology records in HYGEIAnet.

4. Interconnectivity Currently, this system is being expanded in order to

provide interconnectivity between databases in different centers, using the same approach and user interface (see figure 6). In the integrated system, the starting page for navigation through the patient's mini-Web includes a priori established links to medical records of the same patient in co-operating departments. An authorized cardiologist, while viewing the medical record of a specific patient, may request a secure connection to view medical data from the other department. The request triggers the execution of the scripts necessary to construct a mini-Web on the other server and the data may then be viewed in a conventional browser.

Figure 6: Patient’s mini web with established links to other centers

Authorized cardiologists may also insert links to other departments in the medical record of a patient. The discovery of a patient’s medical record in another department involves: a) department selection from the list of cooperating departments; b) patient query for the specific patient in the target department; c) establishment

of a link to the specific patient. Once the link to data in the other center is established, it will appear on the browser form as a hyperlink and the alternative site can be accessed through a simple mouse click (see figure 6).

4.1. The problem of patient identification As described above, given the lack of a universally

unique patient id, identification is based on a set of so called identification traits. However, in Greece, traditional naming conventions mean that the same name can be shared by many individuals. Specifically, since the first son of a family is traditionally named after the paternal grandfather, first cousins often share a name. This makes the verification of a patient's identity within an electronic record difficult to accomplish by automatic means. In consequence, the architecture of the system described here requires the cardiologist to confirm that the data from a remote source do indeed belong to the patient in the local center, based on clinical and other criteria. Once this is verified, the link can be made a permanent part of the patient's record.

4.2. Technical approach Establishing a link to a medical record in a compatible

information system in another department requires access to the system directory described in section 2.3. The system directory provides information on the remote host that is necessary to connect and place a query with the identification traits of the patient in question. When the user selects a department and presses search (as shown in figure 7), a script runs on the remote web server and places the patient query. The execution of the query redirects the user to a page which includes patients matching the criteria placed. The cardiologist may navigate through one or more mini-webs before deciding to establish a link to any of them. Established links appear as hyperlinks on the web page.

Figure 7: Placing a query for a matching patient record in another department of HYGEIAnet.

4.3. Project Status and Prospects As a first step in the deployment of the solution

presented earlier, we have established a link between the cardiology records in the ICU and Cardiology departments in the Venizeleio-Pananion hospital in Heraklion. Since a cardiology patient admitted to the ICU, is then transferred to the cardiology clinic, it is

feasible to maintain a main patient index shared by both databases. In future extensions, however, we plan to use the patient directory service of the HII, which will provide fast access to the patient index of health record systems in the region.

5. Summary This paper presents an approach to achieving

interconnectivity of medical records of cardiology patients. The proposed solution extends an existing system for securely accessing healthcare records using Internet technologies and takes a step in the direction of the I-EHR, a key goal in achieving continuity of care.

Acknowledgements The work reported in this paper has been supported in

part by the PICNIC project (IST-1999-10345) and the project “Crete – a telematics center” funded by the INTERREG II program.

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Address for correspondence. Philip J. Lees Center for Medical Informatics and Health Telematics Applications, ICS-FORTH, P.O. 1385 Heraklion, Crete, 71110 Greece E-mail address: pjlees@ics.forth.gr.