SCHOOL OF COMPUTER STUDIES RESEARCH REPORT SERIES

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1 University of Leeds SCHOOL OF COMPUTER STUDIES RESEARCH REPORT SERIES Report The Design and Development of a Fully Integrated Hospital Information System by T S Chen* & T G Gough Division of Operational Research and Information Systems August 1994 *Department of Medical Informatics, National Cheng Kung University Hospital, Taiwan - 1 -

2 ABSTRACT This paper provides an overview of the design and development of a comprehensive integrated hospital information system for the National Cheng Kung University Hospital. This system was designed for a new hospital to be built on a 'green field' site and was developed and installed as an integral component of the building of the hospital and the installation of the medical and administrative facilities. The approach necessitated the specification of requirements with no users to explain what they need; a study of capacity without the availability of existing data to predict the workload; a performance study in advance of operation to understand system behaviour; and the effective scheduling of implementation to ensure congruence with the building and commissioning of the hospital. 1. INTRODUCTION In Taiwan there was a lag in investment in the development of computer-based hospital information systems (Chang, 1984) and there was an imbalance in the provision of hospitals with some large high quality hospitals in the northern area but no equivalent provision in the south of the country. It was therefore decided that a modern medical school and teaching hospital be built in the southern area, in Tainan. In 1984, the addition of a medical school to the National Cheng Kung University (NCKU) was approved. The teaching hospital project was also approved, with the construction work to start in February 1985, for the hospital to open in January 1988 (though delays in construction delayed the opening until June 1988). In considering information requirements it was noted that the data needed by clinical and administrative personnel have traditionally been managed separately and that when computers have been used to process such data, the tasks are often performed on separate computers. As Wiederhold and Perreault (1990) point out the lack of integrated data from diverse sources creates a host of problems. It was felt to be essential for the NCKU hospital to design and implement a fully integrated computer-based hospital information system to provide the necessary high quality service to the whole hospital. The computer project was one of the key projects in the overall hospital development, since the opening of the NCKU hospital was dependent on its successful completion. A number of existing systems were investigated including the IBM Patient Care System (Mishelvitch et al. 1980) and the HELP system (Pryor et al. 1984) though neither was felt to be suitable for NCKU. The views of Tolchin et al (1984) were noted on the lack of comprehensive functionally integrated hospital information systems that could be used as models. It was therefore necessary to - 2 -

3 design and implement the proposed fully integrated hospital information system for this new system ab initio, as it were. The remainder of this paper sets out some of the key issues faced during design and development and outlines the methods used to address them. 2. SPECIFICATION OF REQUIREMENTS The process of developing a computer-based hospital information system for a new hospital is very different to that for an existing hospital. The existing hospital may have been using manual systems and it has to cope with the impact of automation, and the experience of data conversion problems and parallel operation. There will be a need to ensure the involvement of users to avoid the problems identified by Rusnak (1980) and it will be necessary to examine the needs of those involved in systems installation (Kolenaty, 1984). However, while the new NCKU hospital does not face the problems of automation impact and data conversion it has no immediately available users to consult, no data to analyse and no existing hospital management experience on which to draw. It was not therefore possible to use as a starting point for the terms of reference a statement of the requirements and expectations of the systems' users as suggested by Brookes et al (1982). As the NCKU hospital project had no systems users at the initial study phase it was essential that the members of the planning committee and the study team had the necessary background, experience and skills to frame appropriate terms of reference for the NCKU hospital information system. The users were represented by the study team and the definitions of their needs were approved by the planning committee, taking account of the range of users whose needs are to be met by the integrated hospital information system, (Scherrer, 1988). As there was no existing system and no existing users the planning committee decided to adopt a turnkey solution to obtain the advantages identified by Chard (1988). A set of criteria for judging the turnkey design were determined and included fault tolerance, expansibility, real-time operation, connectivity, confidentiality, ability to handle Chinese characters, and flexibility. Structured analysis techniques based on Yourdon (1989) were used to analyse the application sub-systems for registration, medical records and statistics, inpatients, outpatients and emergency, drug inventory, pharmacy management, medical supplies inventory, laboratory and therapy, dietetic service, nursing care, finance management, personnel management, accounting management, and administration. See Chen (1992) for the detail. After considering the several hardware architectures available to support an integrated hospital information system (Weiderhold and Perreault, 1990) and evaluated the advantages and disadvantages of centralised and decentralised approaches (Bakker et al, 1977 and Flynn, 1983) the planning committee decided to adopt a centralised approach using a multiprocessor machine. As the NCKU hospital would not have its own computer staff before it opened, it had to - 3 -

4 acquire all its software from a vendor. The requirements for systems software, database management and applications software (for all the subsystems identified above) were determined to ensure a smooth handover from the vendor to the hospital's own computer staff as soon as the hospital had sufficient manpower. Communications are needed to support the operational activities of all departments. Data and information are sent over many types of transmission mechanism. A comprehensive hospital information system needs a communication network which includes hardware and software mechanisms. Many authors have addressed the design issues for communication. Bingham and Davies (1977) looked at devices and software. Martin (1981) reviewed the hardware and software requirements of computer networks. Tanenbaum (1981) described Open Systems Interconnection (OSI) communication protocols. Stokes (1986) looked at the OSI model for health care computing in the London area, whereas Halsall (1985) concentrated on RS-232. The NCKU hospital network will enable terminal users in all departments to have controlled access to all the required data within the hospital. Chen and Gough (1989) sets out the key requirements to provide an integrated, flexible communication network capable of meeting the range of NCKU hospital needs taking account of the application parameters identified by Fritz (1985) and Gamble (1988). 3 WORKLOAD FORECASTING Without any existing systems, there is an absence of reference data on which to base workload predictions and yet it is also necessary to process all the information required in the new hospital to ensure sufficient capacity but without incurring high costs. The starting point for the calculation of the total forecast workload is the natural forecast unit (Terplan, 1987). This is the basic resource unit for executing an application procedure. The registration application subsystem is an essential part of the computer-based hospital information system, since every patient who enters the hospital has to be served by this subsystem. During the application design phase this subsystem was given priority and was designed early in the schedule. It was therefore selected as the sample subsystem for the probabilistic model for forecasting the workload. As there are no historical data to which reference can be made, it is necessary to build a probabilistic model of the new application using a graph representation of routine, module and subsystem programs which can be reduced by suitable reduction techniques. See Beizer (1978) for the principles used and Ferrari et al (1983) for an application of the model. The process begins with expressing a program as a flow chart and a graph with nodes and links. Node elimination follows and then the graph reduction procedure is implemented. The estimated workload for the new computerised hospital information system can be determined for routines, modules and subsystems to encompass the whole system. The CPU time and disk capacity for the NCKU hospital information - 4 -

5 system are then calculated and a suitable hardware configuration layout is determined. The probabilistic model proved well suited to predicting the workload without access to historical data. The procedure for simplifying the reduction graph computed the required CPU time for the routines, modules and subsystems to be used. The estimated CPU time proved accurate in terms of the sets of processors required and the estimated database capacity has also matched expectations. These capacity studies provided the required hardware configuration at a reasonable price. A more detailed discussion is to be found in Chen and Gough (1991). 4 PERFORMANCE MODELLING The use of the probabilistic model solves the capacity problem but this still leaves the problem of system performance. Clearly an acceptable level of performance is very important for an operational computer system and it is important to consider performance during the design stage to avoid producing an unacceptable system performance on completion. The main purpose of a performance study is to specify or identify a computer system with adequate operational performance at a reasonable cost. Cost-savings may be large (Sauer and Chandy 1981). A multiple server model with terminals and memory was selected for the performance modelling study to examine the anticipated system performance, with particular attention paid to the response time of the multiprocessor system designed to support the NCKU hospital information system. The processors are identical with one independent operating system in each processor and they share access to common memory. Jobs are despatched on a 'first come, first served' basis. A round robin schedule is used which assigns each processor in turn to all jobs for a given period. The simulation model of the proposed system based on the assumptions already described was implemented. After running the simulation program, the predicted values for the performance measures are obtained from the queuing model. The response time curves are plotted against the number of processors and as expected system response time decreases when the number of processors increases. However, when the expected workload (previously calculated from the workload forecasting model) and the target systems response time of three seconds are taken in consideration, it becomes clear that two sets of processors are always over the time limitations and three sets are very near the limit. Though five or six sets of processors provide better performance than four sets, the costs are higher. The most suitable number of processors is four sets and this outcome is consistent with the workload results from the probabilistic model

6 A more detailed discussion is to be found in Chen and Gough (1992). 5. IMPLEMENTATION As noted earlier, the hospital information system had to be completed successfully and integrated into the operation of the NCKU hospital at the opening date. As this was a new hospital, implementation of the computer system required the preparation of the environment for the equipment, installation of electrical power, air-conditioning and the siting of the cabling and networking, in addition to the design, development and testing of the fourteen application subsystems and all associated hardware and software. A critical feature of the implementation was the effective testing of the installed system to ensure the provision of all the necessary capabilities and functions set out in the specification of requirements to enable the new hospital to provide the planned service, since the hospital would be entirely dependent on the integrated hospital information system for all day-to-day activity. A particular feature of the testing was the involvement of the potential users in the testing process. The activities of about two hundred users were simulated in different kinds of procedures and the systems testing was undertaken by a combined group representing all the relevant departments. This approach was based on the argument that the testing involved many different types of skill and that corporate subsystems were being tested, not systems for separate departments or functions. A test would involve the selection of a patient with a particular condition or needs, identification of the subsystems required to serve that patient and the testing of the subsystems in the logical sequence appropriate to the delivery of the service. System operation was assessed continuously to distinguish between system problems and personnel problems, to ensure correction of errors and re-testing and the feeding of the learning into the training which was a major component of implementation. 6. EVALUATION Evaluation of an integrated hospital information system is an essential but difficult task. The evaluation programme for the NCKU hospital information system was begun at the announcement of the project and carried out by the planning committee to keep the project on track during development. As a system reaches the final phases of development evaluation involves testing whether the system performs correctly, is acceptable to its intended users, and is cost-effective. For the NCKU hospital information system evaluation covered: utilisation, including workload measurement and capacity planning; the measurement of outcomes, including satisfaction of the data processing requirements, information quality, management control and cost effective information delivery; acceptance, including quality of the interface, convenience, speed, reliability, ease of authorised access and integration; security, including password control and authorisation; the computing environment, hardware, software and communications devices, database access, and back-up

7 The overall conclusion of the evaluation, undertaken by internal and external agencies, was that the fully integrated hospital information system for NCKU operated successfully as designed and installed and met its intended goals. 7. CONCLUSION A five-phase approach was adopted for the design development and installation of the NCKU integrated hospital information system. An initial study was followed by the specification of requirements. Capacity and performance studies for the selected system followed, using a specifically developed workload forecasting model and performance modelling to ensure the design offered adequate performance at a reasonable cost. The fourth phase was implementation and finally the system was evaluated to assess the effectiveness of the design in operation. The distinct feature of this system development cycle was the absence of an existing system to provide access to data and user expertise. Techniques were developed to fill these gaps notably in addressing the issues of capacity planning and performance estimation. The NCKU hospital information system was designed and implemented to achieve the integration of information provision across the hospital for all information users in all parts of the hospital. This it has achieved. 8. REFERENCES Bakker, A.R., Louwerse, C.P. and Kouwenberg, J.M.C., (1983), Data Integrity in an Integrated Hospital Information System - Practical Experiences, in Bemmel, Ball and Wigertz (eds.), Proceedings of MEDINFO - 83, North-Holland. Beizer, B., (1978), Micro-Analysis of Computer System Performance, Von Nostrand Reinhold. Bingham, J.E., and Davies, G.W.P., (1977), Planning for Data Communications, Macmillan. Brookes, C.H.P., Grouse, P.J., Jeffrey, J.R. and Lawrence, M.J., (1982), Information Systems Design, Prentice-Hall of Australia. Chang, C.U., (1984), Hospital Management Systems, Ta-Lin Publishing. Chard, T., (1988), Computing for Clinicians, Elmore-Chard Publishing. Chen, T.S., (1992), The Design of a Fully Integrated Hospital Information System, PhD Dissertation, University of Leeds

8 Chen, T.S. and Gough, T.G., (1989), Computer Communication System for NCKU Hospital, in Barker, Cas, Qin and Wagner (eds.), Proceedings of MEDINFO - 89, North-Holland. Chen, T.S. and Gough, T.G., (1991), Workload Forecasting Study for a Computerised Hospital Information System, in Hedley and Wong (eds.) Proceedings of the First Hong Kong Medical Informatics Conference, Hong Kong Society of Medical Informatics and the Hong Kong Computer Society. Chen, T.S. and Gough, T.G., (1992), Performance Modelling Study for a Hospital Information System, in Lun, Degoulet, Piemme and Rienhoff (eds.), Proceedings of MEDINFO - 92, North-Holland. Ferrari, D., Serazzi, G. and Zeigner, A., (1983), Measurement and Tuning of Computer Systems, Prentice-Hall. Flynn, F.V., (1983), Laboratory Data Processing Using a Network of Computers, in Fokkens, (ed.), Proceedings of MEDINFO - 83 Seminars, North-Holland. Fritz, J.S., (1985), Local Area Networks - Selection Guidelines, Prentice-Hall. Gamble, J.N., (1988), Practical Networking and Standards Today, in Bakker, Ball, Scherrer and Willems, (eds.), Towards New Hospital Information Systems, North-Holland. Halsall, F., (1985), Data Communication and Computer Networks, Addison- Wesley. Kolenaty, G., (1984), Hospital Information System Planning, in Blum. (ed.), Information Systems for Patient Care, Springer-Verlag. Martin, J., (1981), Computer Networks and Distributed Processing, Prentice- Hall. Mishelwich, D.J., Hudson, B.G., Slyke, D.V., Mize, E.I. and Robinson, A.L., (1980), Implementation of the IBM Health Care Support and Patient Care System, in Proceedings of the Fourth Annual Symposium on Computer Application in Medical Care, IEEE. Pryor, T.A., Gardner, R.M., Clayton, P.D. and Warner, H.R., (1984), The HELP System, in Blum. (ed.), Information Systems for Patient Care, Springer-Verlag. Rusnak, J.E., (1980), The Conduct of a Health Care System Project, in Proceedings of the Fourth Annual Symposium on Computer Applications in Medical Care, IEEE. Sauer, C.H. and Chandy, K.M., (1981), Computer Systems Performance Modelling, Prentice-Hall

9 Scherrer, J.R., (1988), Retrospective and Prospective Usefulness of HIS, in Bakker, Ball, Scherrer and Willems, (eds.), Towards New Hospital Information Systems, North-Holland. Stokes, A.V., The OSI Model and Health Care Computing, in Bryant, Roberts and Windsor, (eds.), Conference Proceedings of Current Perspectives in Health Computing, British Journal of Health Care Computing. Tanenbaum, A.S., (1981), Computer Networks, Prentice-Hall. Terplan, K., (1987), Communication Network Management, Prentice-Hall. Tolchin, S.G., Stewart, R.L. and Kahn, S.A., (1984), Implementation of a Prototype Generalised Network Technology for Hospitals, in Blum (ed.) Information Systems for Patient Care, Springer-Verlag. Wiederhold, G. and Perreault, L.E., (1990), Hospital Information Systems, in Shortcliffe, Perreault, Wiederhold and Fagan, (eds.), Medical Information - Computer Applications in Health Care, Addison-Wesley. Yourdon, E., (1985), Modern Structured Analysis, Prentice-Hall