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Biomedical subjects

A Abu-Hanna

Publications and source records attributed to A Abu-Hanna.

13 recordsLinked to original sources
PubMed2006

Short-term and long-term mortality in very elderly patients admitted to an intensive care unit.

OBJECTIVE: To report short-term and long-term mortality of very elderly ICU patients and to determine independent risk factors for short-term and long-term mortality DESIGN AND SETTING: Retrospective cohort study in the medical/surgical ICU of a tertiary university teaching hospital. PATIENTS: 578 consecutive ICU patients aged 80 years or older. RESULTS: Demographic, physiological, and laboratory values derived from the first 24h after ICU admission. ICU mortality of unplanned surgical (34.0%) and medical patients (37.7%) was higher than that of planned surgical patients (10.6%), as was post-ICU hospital mortality (26.5% and 29.7% vs. 4.4%). Mortality 12 months after hospital discharge, including ICU and hospital mortality, was 62.1% in unplanned surgical and 69.2% in medical patients vs. 21.6% in planned patients. Only median survival of planned surgical patients did not differ from survival in the age- and gender-matched general population. Independent risk factors for ICU mortality were lower Glasgow Coma Scale score, higher SAPS II score, the lowest urine output over 8 h, abnormal body temperature, low plasma bicarbonate levels, and higher oxygen fraction of inspired air. High urea concentrations and admission type were risk factors for hospital mortality, and high creatinine concentration was an independent risk factor for 12-month mortality. CONCLUSION: Mortality in very elderly patients after unplanned surgical or medical ICU admission is higher than after planned admission. The most important factors independently associated with ICU mortality were related to the severity of illness at admission. Long-term mortality was associated with renal function.

Aged↗
PubMed2006

A framework for characterizing terminological systems.

OBJECTIVES: The notion of a terminological system (TS) is complex due to the broad range of systems, applications, and clinical domains. A uniform approach to describe the characteristics of TSs is lacking. This impedes furthering understanding, applicability, mutual comparison and development of TSs. For these reasons we propose a terminological systems characterization framework. METHODS: Relevant issues pertaining to TSs and terminology servers have been extracted from literature describing requirements and functionality of TSs. From these issues, features have been distilled and further refined. A categorization has been developed to provide a convenient arrangement of these features. RESULTS: The framework distinguishes between application-dependent and application-independent features of TSs. Definitions are provided for measures of content coverage, which was identified as the only application-dependent feature. Application-independent features are categorized along two axes: their respective type of TS and the particular element within that system, i.e. the formalism, the content, or the functionality. For each feature we provide an explicit question, the answer to which yields a feature value. The framework has been applied to SNOMED CT and the CLUE browser. CONCLUSIONS: We present and apply a framework to support a feature-based characterization of terminological systems. Standardized methods for content coverage studies reduce the effort of assessing the applicability of a TS for a specific clinical setting. A two-axial categorization provides a convenient arrangement of the large number of application-independent features. Application of the framework increases comparability of terminological systems. This framework may also help TS developers determine how their system can be improved.

Medical Informatics Applications↗
PubMed2006

Characterizing Decision Support Telemedicine Systems.

OBJECTIVES: Decision Support Telemedicine Systems (DSTS) are at the intersection of two disciplines: tele-medicine and clinical decision support systems (CDSS). The objective of this paper is to provide a set of characterizing properties for DSTSs. This characterizing property set (CPS) can be used for typing, classifying and clustering DSTSs. METHODS: We performed a systematic keyword-based literature search to identify candidate-characterizing properties. We selected a subset of candidates and refined them by assessing their potential in order to obtain the CPS. RESULTS: The CPS consists of 14 properties, which can be used for the uniform description and typing of applications of DSTSs. The properties are grouped in three categories that we refer to as the problem dimension, process dimension, and system dimension. We provide CPS instantiations for three prototypical applications. CONCLUSIONS: The CPS includes important properties for typing DSTSs, focusing on aspects of communication for the telemedicine part and on aspects of decisionmaking for the CDSS part. The CPS provides users with tools for uniformly describing DSTSs.

Decision Support Systems, Clinical↗
PubMed2005

[Admission of elderly patients to intensive care].

Elderly patients have an increased probability of dying after treatment in an intensive care unit (ICU), compared with younger patients. The risk of dying is largely determined by the admission type (patients with planned admissions have a better prognosis than those with unplanned admissions), severity of illness and functional status prior to admission. Elderly patients surviving ICU often experience a decline in functional status. No data are available on the factors that predict functional outcome. Elderly patients do not necessarily prefer life-sustaining treatment to palliative care. The willingness to undergo ICU treatment depends on the likelihood of survival and beneficial functional outcome. New prognostic models should be developed specifically to predict both survival and functional outcome in individual elderly patients after admission to ICU.

Age Factors↗
PubMed2002

Usability of expressive description logics--a case study in UMLS.

Research in (medical) terminological knowledge representation is showing an increased interest in the family of Description Logics (DLs), as they allow for automatic reasoning. This interest is driven by an increase in demands on the quality of and reasoning ability with medical terminological knowledge. Recent advances in Computer Science have demonstrated the computational decidability and empirical tractability of quite expressive DLs. The question arises whether this expressivity is usable and useful. This paper motivates and describes an exploratory study to address this question by examining the surplus value of individual DL constructors based on an investigation of UMLS terms. Our study indicates that the disjunction and negation operators comprise very valuable extensions to current DLs. The impact of formalization depends on the involved semantic type; "Injury and Poisoning" is one of the semantic types in which a large portion of concepts will benefit from the extension.

Logic↗
PubMed2002

Software engineering in medical informatics: the academic hospital as learning environment.

In 2001, the revised course Software Engineering has been implemented in the Medical Informatics curriculum at the Academic Medical Center, Amsterdam. This 13 weeks, full-time course consists of three parts: internship, theory and project. All parts are provided in problem-oriented manner with special attention for relevant skills such as project management, documentation and presentation. During the internship, students observe how health care professionals at several hospital wards work and how information supply is organized. In the theory part, students study concepts and methods of software engineering by means of case descriptions and self-directed learning. During the project, they apply their acquired knowledge to an observed, clinical information problem and complete several stages of the software engineering process. Evaluation by inquiry showed that, compared to other courses, students spent more time, and distributed their time more evenly, during the whole period of the course. In conjunction with theory, a combination of internship and project in a hospital seems to provide a surplus value compared to a practical in a computer laboratory. The integration of software theory, clinical practice and problem-based approach, contributed to the enthusiastic, intensive and realistic way students learned in this important topic that might be chosen as a future profession.

Curriculum↗
PubMed2000

Understanding terminological systems. I: Terminology and typology.

Terminological systems are an important research issue within the field of medical informatics. For precise understanding of existing terminological systems a referential framework is needed that provides a uniform terminology and typology of terminological systems themselves. In this article a uniform terminology is described by putting relevant fundamental notions and definitions used by standard organizations such as CEN and ISO into perspective, and interrelating them to arrive at a useful typology of terminological systems. This typology is illustrated by applying it to five well-known existing terminological systems.

Humans↗
PubMed2000

Understanding terminological systems. II: Experience with conceptual and formal representation of structure.

This article describes the application of two popular conceptual and formal representation formalisms, as part of a framework for understanding terminological systems. A precise understanding of the structure of a terminological system is essential to assess existing terminological systems, to recognize patterns in various systems and to build new terminological systems. Our experience with the application of this framework to five well-known terminological systems is described.

Humans↗
PubMed2000

Evaluation of DICE, a terminological system for intensive care.

Evaluative research and the introduction of the Patient Data Management System to support care have increased the need for structured and standardized registration of diagnostic information in Dutch intensive cares (IC). To this end a terminological system to describe diagnoses is needed. A terminological system is a system that denotes terms to concepts in a domain based on specifications of these concepts. During the last two years we have developed DICE (Diagnoses for Intensive Care Evaluation), a terminological system application which includes knowledge about the IC diagnoses domain, such as the anatomical localization, the pathophysiology and the etiology. This paper briefly describes the design of DICE and focus on the preliminary evaluation of DICE. DICE was evaluated on the basis of 126 diagnoses collected. The knowledge modeller as well as the intensivists judged DICE positively. However, there were some points for improvement. The knowledge modeller observed a problem in modelling dependencies between qualifiers of a concept and the intensivists observed some gaps in the knowledge base and were critical about the current interface to compose plural operative procedures.

Critical Care↗
PubMed1999

Prognostic methods in medicine.

Prognosis--the prediction of the course and outcome of disease processes--plays an important role in patient management tasks like diagnosis and treatment planning. As a result, prognostic models form an integral part of a number of systems supporting these tasks. Furthermore, prognostic models constitute instruments to evaluate the quality of health care and the consequences of health care policies by comparing predictions according to care norms with actual results. Approaches to developing prognostic models vary from using traditional probabilistic techniques, originating from the field of statistics, to more qualitative and model-based techniques, originating from the field of artificial intelligence (AI). In this paper, various approaches to constructing prognostic models, with emphasis on methods from the field of AI, are described and compared.

Artificial Intelligence↗
PubMed1999

Analysis and design of an ontology for intensive care diagnoses.

Information about the patient's health status and about medical problems in general, play an important role in stratifying a patient population for quality assurance of intensive care. A terminological system which supports both the description of health problems for daily care practice and the aggregation of diagnostic information for evaluative research, is desirable for description of the patient population. This study describes the engineering of an ontology that facilitates a terminological system for intensive care diagnoses. We analyzed the criteria for such an ontology and evaluated existing terminological systems according to these criteria. The analysis shows that none of the existing terminological systems completely satisfies all our criteria. We describe choices regarding design, content and representation of a new ontology on which an adequate terminological system is based. The proposed ontology is characterized by the explicit and formal representation of the domain model, the metaspecification of its concepts, the vocabulary to define concepts and the nomenclature to support the composition of new concepts.

Diagnosis, Computer-Assisted↗
PubMed1995

A case study in ontology library construction.

The goal of our work is to facilitate the development of medical knowledge-based systems by providing a library of reusable ontologies. The availability of such a library reduces the amount of knowledge acquisition required to create knowledge bases of new applications, and makes it easier to connect a knowledge-based system to existing data bases. This article presents a case study in constructing such a library. The emphasis is on studying the principles that underly the internal structure of the library as well as on the process of constructing and using the library. We envision that, in the future, application ontologies can be constructed by the selection and refinement of generic ontologies and domain ontologies from such a library.

Artificial Intelligence↗