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A study of the usage of a decision-support system for infective endocarditis
Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
2000 (English)In: Medical informatics and the Internet in medicine (Print), ISSN 1463-9238, E-ISSN 1464-5238, Vol. 25, no 1, 1-18 p.Article in journal (Refereed) Published
Abstract [en]

The objective of this study was to examine a design for a World Wide Web-based decision-support system in use by clinically active physicians. A prototype implementation of the design concerned management of infective endocarditis patient cases. The design was based on an integration of hypertext and rule-based knowledge. In the study sessions, physicians in the field of internal medicine worked on managing authentic patient cases in a laboratory setting. Data was collected from interviews with the physicians using video recordings and stimulated recall technique. The qualitative data was analysed according to the constant comparative method in order to develop a model of the physicians' usage of the system. The resulting model describes perceived contributions and criteria for usefulness of the system. The ways the physicians used the system showed that it was able to provide patient-specific support for confirming clinical decisions, for higher-level patient management, and for preparing for and initiating expert consultations. Users also stated that new medical knowledge could be gained as a side effect of using the system.

Place, publisher, year, edition, pages
2000. Vol. 25, no 1, 1-18 p.
Keyword [en]
Decision-support System, Endocarditis, Qualitative Methodology, Evaluation
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-13334DOI: 10.1080/146392300298229OAI: oai:DiVA.org:liu-13334DiVA: diva2:18507
Available from: 2008-06-18 Created: 2008-06-18 Last updated: 2017-12-13
In thesis
1. Infective Endocarditis: aspects of pathophysiology, epidemiology, management and prognosis
Open this publication in new window or tab >>Infective Endocarditis: aspects of pathophysiology, epidemiology, management and prognosis
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Infective endocarditis (IE) is a rare but complex disease that is fatal if untreated. With a modern combination of antimicrobial therapy and heart valve surgery, mortality is still 10-20 %. The structure of the endocarditis vegetation impedes the penetration of phagocytic cells such as monocytes and granulocytes. This leads to high bacterial counts inside the vegetation and the need for long treatment courses with a combination of intravenously administered bactericidal antibiotics.

The aim of this thesis was to study the changes in epidemiology, management, and mortality at our hospital between 1980 and 2001, and to identify prognostic factors associated with mortality. To assess the issue of referral bias, differences between referred episodes and episodes from our local community were studied. Additional aims were to study the occurrence of the pro-chemotactic cytokines IL-8 and TNF-α in heart valves and vegetations during the active phase of IE, and to study the effect of the glycopeptide antibiotic vancomycin in dense staphylococcal cultures in vitro. As it is a rare and complex disease, management of IE is usually complicated for non-specialists. For this reason a computerised decision support system for IE was developed and evaluated.

Between 1980 and 2001, the occurrence of Staphylococcus aureus IE and the use of early heart valve surgery increased significantly, regardless of whether the episodes were referred or of local origin. Glycopeptide antibiotics, mainly vancomycin, were used more frequently, especially among referred patients. Referred patients were younger, predominantly male, had more complications, and received surgical treatment more often than patients from our local community. The reason for the lower frequency of female patients in the referral cohort cannot be explained by more comorbidity or fewer complications. The differences between referred and local episodes seen in our study highlight the need for assessment and adjustment for referral bias in IE studies (Paper I).

In six patients who needed early heart valve surgery, the largest numbers of IL-8-containing cells, and the greatest amount of inflammation, were seen in patients with short preoperative antimicrobial treatment courses. No such relationships were seen with respect to TNF-α-containing cells. The IL-8-containing cells and the inflammatory cells were predominantly scattered in the heart valve stroma or in the margin of the vegetation (Paper II). The primary effect of IL-8 is to stimulate chemotaxis of polymorphonuclear neutrophil granulocytes. This indicates that there is no deficiency of IL-8 in the area close to the vegetation as a cause of the localised agranulocytosis often present inside the vegetation.

Our study revealed a need for computerised decision support systems (DSSs) in the field of IE, but to be used in clinical practice these DSSs need be part of knowledge bases covering larger domains (Paper IV). Some of our initial ideas described in Paper III, especially the use of Internet technology and the combination of rule-based advice and explanatory hypertext, will probably be included in these knowledge bases.

In vitro, there is a rapid reduction of free vancomycin in broth containing dense staphylococcal cultures. Consequently, there is a simultaneous increase in broth MICs, particularly in high inocula, which is not caused by a development of resistance (Paper V). These findings need further evaluation in vivo, but indicate that the dosing regimen of vancomycin is of particular importance in staphylococcal infections with dense inocula, e.g. infective endocarditis.

Diabetes mellitus and moderate to severe heart failure were independent risk factors for 6-month mortality in left-sided, Duke definite IE episodes, regardless of referral or local origin of the episodes. Early heart valve surgery had a positive impact on the 6-month mortality in the referral cohort of episodes, which may be due to referral bias (Paper VI).

Place, publisher, year, edition, pages
Linköping University Electronic Press, 2008. 42 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1017
Keyword
epidemiology, Infective endocarditis (IE), heart valve surgery, monocytes, granulocytes, staphylococ
National Category
Public Health, Global Health, Social Medicine and Epidemiology
Identifiers
urn:nbn:se:liu:diva-12274 (URN)978-91-85895-83-0 (ISBN)
Public defence
2008-05-14, Elsa Brändströmsalen, Campus US, Linköpings universitet, Linköping, 13:00 (English)
Opponent
Supervisors
Available from: 2008-06-18 Created: 2008-06-18 Last updated: 2015-11-19
2. Aspects of the use of medical decision-support systems: the role of context in decision support
Open this publication in new window or tab >>Aspects of the use of medical decision-support systems: the role of context in decision support
2001 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is a great need today for distribution of medical information. The amount of information is growing quickly, and information that could potentially influence clinical practice fails to reach health care professionals. The supply of information to health care has from the start been the main goal of medical informatics. However, with very few exceptions, the systems developed to support the formalization and distribution of medical knowledge, i.e. decision-support or expert systems, have not attained clinical use. Thus, since there is an unsatisfied need for information and the methods developed so far have been successful to only a limited extent, it is important to gain insight into both how decision-support systems are used and which of their properties may influence the usability.

This thesis describes aspects of the use of medical decision-support systems by looking at two prototype implementations of such systems. The prototypes concerned bacterial endocarditis and urinary tract infections respectively. The first prototype system was evaluated and a theory of the use of the system was developed, thereby leading to further theorization and the development of a new system design. The goal of the system designs was to facilitate the interpretation and assessment of generated advice. This kind of support was realized by applying an expertext system model, a model that supports triangulation of decision-support methods and information sources. To organize the information in an expertext environment, a common terminological domain model was used in the second system design. In the theorization, a special focus was on contextual aspects of system use. Differences between knowledge provider and end-user contexts concerning the use of decision-support systems were analyzed. The importance of support for multi-perspective interpretation of system output such as is present in our system designs was confirmed.

Place, publisher, year, edition, pages
Linköping: UNIT, 2001. 45 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 662
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-29007 (URN)14240 (Local ID)91-7219-896-6 (ISBN)14240 (Archive number)14240 (OAI)
Public defence
2001-01-09, Sal 1, Farmakologen, Plan 8, Universitetssjukhuset, Linköping, 09:00 (Swedish)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2013-02-19

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Ekdahl, ChristerKarlsson, DanielWigertz, OveForsum, Urban

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