T. Timmers

Morphological, haemodynamic, and clinical variables as predictors for management of isolated ventricular septal defect.

OBJECTIVE--To assess the predictive impact of morphological, haemodynamic, and clinical variables in the management of patients with isolated ventricular septal defect. DESIGN--Retrospective analysis of variables by a sophisticated database management system. PATIENTS AND METHODS--263 consecutive patients with isolated ventricular septal defect diagnosed by echocardiography. The morphological type and haemodynamic character of the ventricular septal defect was characterised in each patient. In addition, variables were introduced to represent the need for diuretics, growth, and potential delay in growth. In 43 patients (16.3%) the ventricular septal defect was closed surgically; 220 patients (83.7%) were managed conservatively and spontaneous closure of the ventricular septal defect occurred in 65 (29.5%). There were no deaths. RESULTS--All patients managed surgically had non-restrictive defects and were operated on during the first year of life. A few patients with non-restrictive defects were managed conservatively. The two groups differed significantly only with respect to mean growth delay (0.65 (0.27) v 0.9 (0.21), P < 0.001). Only the morphology of the ventricular septal defect significantly (P < 0.001) influenced the probability of closure. CONCLUSIONS--Findings imply that early surgical closure of ventricular septal defect is indicated in patients with non-restrictive ventricular septal defect and severe growth delay. Other patients should be managed conservatively. In these patients the morphological type of the defect determines the probability of spontaneous closure and provides an estimate of the period over which decreased in size or closure can be expected.

HERMES: a health care workstation integration architecture

An architecture is described that facilitates integration of existing databases and applications without modifying them. By means of this architecture, data from different sources dispersed in a network can be combined and directly used in existing applications or applications that have been developed specially for integration. This feature of combining data from different sources into one workstation is viewed as the enabling technology on which computer-based patient records can be built. The abstraction of computer-, network- and application-specific details is completely dealt with by the integration architecture. This integration architecture has been developed with extendibility and flexibility in mind, and allows for a growth-path towards application of the open system paradigm in medicine.

A prototype integrated medical workstation environment

In this paper the requirements, design, and implementation of a prototype integrated medical workstation environment are outlined. The aim of the workstation is to provide user-friendly, task-oriented support for clinicians, based on existing software and data. The prototype project has been started to investigate the technical possibilities of graphical user-interfaces, network technology, client-server approaches, and software encapsulation. Experience with the prototype encouraged discussion on both the limitations and the essential features for an integrated medical workstation.

Trends in Integrated Clinical Workstations

During the last decade, several projects aiming at integrated clinical workstations have been described and several prototypes have been demonstrated. In most of these projects, the clinical workstation accesses information and functionality provided by the present proprietary legacy systems of health-care institutions. We discuss trends in integrated clinical workstations from the viewpoints of software engineering and integration, considering that the clinical workstation itself basically consists of three layers: a presentation layer, a data integration layer, and a communication layer. The software engineering view on clinical workstations focuses on the development of basic building blocks from which clinical workstations, specific to a particular medical domain, can be composed. The integration view on clinical workstations addresses methods and techniques to deal with the, in general, intrinsically closed information systems in health-care institutions.

Knowledge-based modeling for the classification and follow-up of patients with congenital heart disease

A model is presented for the support of clinical research in the domain of pediatric cardiology, in particular the long-term follow-up of patients with congenital heart disease (CongHD). It can be used for the collection, storage, retrieval, and analysis of data on a variety of hardware platforms. Using an object-oriented approach, a datamodel and an extensive controlled vocabulary of CongHd has been created. The model is part of the Medical Workstation 2000, an integrated graphical environment for the support of clinical research. The general structures of the model and of the vocabulary are described.<<ETX>>

CW2000: a medical workstation to support research in cardiology

The development of CW2000, an integrated workstation to support clinical research in cardiology is described. Four levels of integration are discussed: the levels of hardware, software, data and user-interface. The architecture of the system allows integration in a user-friendly shell of software packages currently in use for clinical research. The design and implementation of the workstation architecture are described. The workstation environment can be extended easily with other functions and the techniques for integration can be adapted for use in other clinical environments. The current status of the project, evaluation plans, and the trend for generalizing the concepts of integration are discussed.<<ETX>>

An interactive implementation of nonparametric partitioning in ISPAHAN

ISPAHAN, an interactive system for pattern analysis, is described. It features methods for the supervised and unsupervised design of classification strategies, for the design and display of scatter plots and other mappings from high-dimensional space onto a plane, for feature vector transformations, and other interactive techniques designed to facilitate the analysis and interpretation of data in high-dimensional feature spaces. ISPAHAN may also be thought of as a tool for the acquisition of structured knowledge from feature vector data. Since this tool is designed to be versatile and applicable to a variety of feature vector distributions, parametric as well as nonparametric decision functions have been implemented from the beginning. A recent addition to the arsenal of functions is an interactive version of a nonparametric partitioning technique. The implementation and the advantages of interaction are outlined.<<ETX>>