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Biomedical subjects

A Geissbuhler

Publications and source records attributed to A Geissbuhler.

17 recordsLinked to original sources
PubMed2006

Guarantying the quality of chemotherapy: from the order to the administration.

Ensuring the quality and security when prescribing drugs like chemotherapies is a complex task if one wants to cover the whole chain from the prescribing physician to the administrant nurse. At the University hospitals of Geneva, new applications covering the whole chain from the prescription up to and including the fabrication of the products have been developed in three phases and are being used in a production stage. In order to cover the "last yard" at the bed level, a fourth phase has been started with a pilot study based on labels containing RFID chips for preparations and for patients. The last phase will make use of all traceability data acquired from the prescription to the preparation to validate that the right product is administered to the right patient, and to record who is administrating it.

Drug Therapy↗
PubMed2006

Impact of CPOE on mortality rates--contradictory findings, important messages.

OBJECTIVE: To analyze the seemingly contradictory results of the Han study (Pediatrics 2005) and the Del Beccaro study (Pediatrics 2006), both analyzing the effect of CPOE systems on mortality rates in pediatric intensive care settings. METHODS: Seven CPOE system experts from the United States and Europe comment on these papers. RESULTS: The two studies are not contradictory, but almost non-comparable due to differences in design and implementation. They demonstrate the range of outcomes that can be obtained from introducing informatics applications in complex health care settings. Implementing informatics applications is a sociotechnical activity, which often depends more on the organizational context than on a specific technology. As health informaticians, we must not only learn from failures, but also avoid both uncritical scepticism that may arise from drawing overly general conclusions from one negative trial, as much as uncritical optimism from limited successful ones. CONCLUSION: The commentaries emphasize the need to promote systematic studies for assessing the socio-technical factors that influence the introduction of increasingly sophisticated informatics applications within complex organizations. The emergence of evidence-based health informatics will be based both on evaluation guidelines and implementation guidelines, both of which increase the chances of successful implementation. In addition, well-educated health informaticians are needed to manage and guide the implementation processes.

Europe↗
PubMed2002

Controlling the vocabulary for anatomy.

When confronted with the representation of human anatomy, natural language processing (NLP) system designers are facing an unsolved and frequent problem: the lack of a suitable global reference. The available sources in electronic format are numerous, but none fits adequately all the constraints and needs of language analysis. These sources are usually incomplete, difficult to use or tailored to specific needs. The anatomist's or ontologist's view does not necessarily match that of the linguist. The purpose of this paper is to review most recognized sources of knowledge in anatomy usable for linguistic analysis. Their potential and limits are emphasized according to this point of view. Focus is given on the role of the consensus work of the International Federation of Associations of Anatomists (IFAA) giving the Terminologia Anatomica.

Anatomy↗
PubMed2001

Paragraph-oriented structure for narratives in medical documentation.

The authors present a 6 years experiment using a document- centered electronic patient record, based on a central document repository. The document management system is paragraph oriented and all documents are built automatically before editing using predefined ordered sets of para-graphs. Paragraphs can be preloaded with templates, text or images. Once edited, signed and printed, documents are again decomposed in paragraphs and permanently stored. This system, though the compositional aspect of paragraphs is limited and their semantic content wide, offers numerous advantages. The typology is easy to build and to maintain, it has been implemented widely in our hospitals without need for any natural language processing techniques and is used daily within commercially available text editors. The actual state of the system is discussed, emphasizing the structure of the documents, the various attributes and properties that have been needed in order to meet user's needs.

Documentation↗
PubMed2001

Experience with an XML/HTTP-based federative approach to develop a hospital-wide clinical information system.

The authors present a two-year experience with an approach aimed at federating applications into a component-based hospital-wide clinical information system. Recognizing the need for better integration, clearer separation of knowledge from applications, as well as the necessity to respect and integrate the diversity of roles in a healthcare network, a strategy was implemented that included the development of a shared vision, organizational changes to promote appropriation at all levels, and the elaboration and maintenance of a common architecture and terminology by an instrumental technical group. Choices for federative technologies were in part based on their level of acceptance and potential to evolve. XML was used as the syntactic framework and HTTP as the transfer protocol. Within twelve months, the shared vision was developed, the architecture was specified, the key central components implemented, incorporated into the applications, and applications teams started producing shareable services using XML and HTTP.

Hospital Information Systems↗
PubMed2001

Use of handheld computers as bedside information providers.

Access to clinical reference information at the point-of-care is a goal that is difficult to achieve by lack of really portable reference material. Handheld computers have matured to the point where they are powerful enough to be used as clients of a distributed knowledge system serving reference information and decision-aid applications in a highly portable form factor. We describe a pilot project launched at the Geneva University Hospital studying the use of handhelds and associated clinical applications in two internal medicine clinics. Results garnered by this study will help answer the many questions raised by the use of handhelds in medical practice, in term of cost, benefits, risk and change in workflow.

Hospitals, University↗
PubMed1999

Distributing knowledge maintenance for clinical decision-support systems: the "knowledge library" model.

The maintenance of knowledge-rich clinical decision-support systems is challenging, in particular in the complex setting of a large academic medical center. Distributing the maintenance tasks to the source of expertise can address scalability, accuracy and currency issues. It also helps to foster a more global sense of ownership among the system users. The knowledge maintenance model must provide processes and tools to deal with a wide range of stakeholders (resident and attending physicians, consulting specialists, other care providers, case managers, ancillary departments), with knowledge embedded in legacy departmental systems, and with the continuous evolution of the content and form of the knowledge base. We describe and illustrate the "knowledge library" model in use at Vanderbilt University Medical Center for the distributed maintenance of the integrated knowledge base that drives the WizOrder clinical decision-support, physician order entry, and notes capture system.

Artificial Intelligence↗
PubMed1999

A programmable rules engine to provide clinical decision support using HTML forms.

The authors have developed a simple method for specifying rules to be applied to information on HTML forms. This approach allows clinical experts, who lack the programming expertise needed to write CGI scripts, to construct and maintain domain-specific knowledge and ordering capabilities within WizOrder, the order-entry and decision support system used at Vanderbilt Hospital. The clinical knowledge base maintainers use HTML editors to create forms and spreadsheet programs for rule entry. A test environment has been developed which uses Netscape to display forms; the production environment displays forms using an embedded browser.

Artificial Intelligence↗
PubMed1998

Clinical application of the UMLS in a computerized order entry and decision-support system.

Vanderbilt University Medical Center uses the UMLS as a dictionary, an interlingua, and a knowledge source within the WizOrder system. WizOrder provides direct care-provider order entry and integrated clinical decision-support capabilities. Linking the two functions enables efficient decision-support during the "normal" workflow of care providers, at the point where decisions are made. WizOrder uses the UMLS as a dictionary to encode free-text entries into controlled vocabularies such as ICD9. As an interlingua, the UMLS provides mapping between vocabularies, allowing to translate patient-specific information to MeSH terms and perform automated literature retrieval. WizOrder uses the tables of co-occurring concepts and the Semantic Network to provide sensible lists of potential drug interactions and adverse drug reactions, and generate fully-formed MEDLINE queries for PubMed.

Decision Support Systems, Clinical↗
PubMed1997

Web-based data integration and annotation in the intensive care unit.

Integrating patient data to facilitate review and annotation is a challenging task in the intensive care unit (ICU), partially due to the wide variety of proprietary systems and types of data involved. This paper describes SIMON-Web, a Java-based user interface to integrate data from an existing bedside monitoring system and a clinical information system (CIS). SIMON-Web displays graphical data from physiologic monitors and other bedside devices as well as information from the clinical laboratory and physician order-entry systems, and allows users to annotate the data using a point-and-click or free-text interface. By continuing to add functionality to SIMON-Web's extensible user interface, we hope to continue to augment and eventually replace manual care provider data charting in the ICU. As of March, 1997, SIMON-Web has been implemented on two bedside personal computer workstations in the cardiac care unit (CCU) at Vanderbilt University Medical Center.

Computer Communication Networks↗
PubMed1994

A performance study of 3D reconstruction algorithms for positron emission tomography.

This paper investigates the statistical and systematic accuracy of five three-dimensional reconstruction algorithms for multi-ring PET scanners operated without septa: the reprojection method, the direct Fourier reconstruction, the FAVOR algorithm, and the single-slice and multi-slice rebinning algorithms. Simulated data of a uniform cylinder, of Gaussian sources, and of spherical sources are used to compare respectively the noise properties, the modulation transfer function, and the recovery coefficients of the algorithms. Brain scans reconstructed with the different algorithms are compared by calculating the linear regression of the mean values within regions of interest. The most significant observations are a slight loss of transaxial resolution with the reprojection algorithm in the external slices of the scanner, and increased noise in the images reconstructed using multi-slice rebinning.

Algorithms↗
PubMed1994

Rotating positron tomographs revisited.

We have compared the performance of a PET scanner comprising two rotating arrays of detectors with that of the more conventional stationary-ring design. The same total number of detectors was used in each, and neither scanner had septa. For brain imaging, we find that the noise-equivalent count rate is greater for the rotating arrays by a factor of two. Rotating arrays have a sensitivity profile that peaks in the centre of the field of view, both axially and transaxially. In the transaxial plane, this effect offsets to a certain extent the decrease in the number of photons detected towards the centre of the brain due to self-absorption. We have also compared the performance of a rotating scanner to that of a full-ring scanner with the same number of rings. We find that a full-ring scanner with an axial extent of 16.2 cm (24 rings) is a factor of 3.5 more sensitive than a rotating scanner with 40% of the detectors and the same axial extent.

Brain↗
PubMed1993

A rotating PET scanner using BGO block detectors: design, performance and applications.

Recent advances in fully three-dimensional reconstruction for multi-ring PET scanners have led us to explore the potential of a prototype scanner based on the rotation of two opposing arrays of BGO block detectors. The prototype contains only one-third of the number of detectors in the equivalent full ring scanner, resulting in reduced cost. With a lower energy threshold at 250 keV, the absolute efficiency of the scanner is 0.5% and the scatter fraction is 35% for a 20-cm cylinder. Transaxial and axial spatial resolution is about 6 mm. The maximum noise equivalent count rate estimated for a 15-cm diameter cylinder is 36,000 cps at a concentration of 26 kBq/ml. The minimum scan time for a 18F-fluoro-2-deoxyglucose (FDG) brain study is 55 sec. The camera has been validated for clinical applications using both FDG and 82Rb.

Algorithms↗
PubMed1991

A normalization technique for 3D PET data.

Prior to reconstruction, emission data from a multi-ring PET camera must be corrected (normalized) for variations in detector sensitivity. The appropriate correction coefficients are obtained by measuring the response of all coincidence lines to a calibrated source of activity (a blank scan). State-of-the-art cameras may contain up to a million such lines of response (LORs), and therefore around 400 million counts will be required to calibrate each LOR to a statistical accuracy of 5%. Alternatively, by modelling the LOR sensitivity as the product of the individual detector efficiencies and a geometrical factor, a calibration procedure has been proposed which requires the determination of only 6000 parameters from this same data set. A significant improvement in the statistical accuracy of the coefficients can therefore be expected. Recently, multi-ring scanners have been operated with the septa retracted, increasing the number of measured LORs by a factor of eight. The acquisition of the calibration data necessary to achieve adequate statistical accuracy then becomes prohibitive. We show that, by modelling the LOR sensitivity, it is possible, with certain approximations, to normalize a septa-retracted emission data set with good accuracy. The input to the model is a high statistics blank scan acquired with the septa extended, which offers a number of practical advantages.

Calibration↗
PubMed1991

Normalisation and reconstruction of PET data acquired by a multi-ring camera with septa retracted.

Emission scan data acquired by a multi-ring PET camera operated with septa retracted must be corrected for (1) geometrical and detector sensitivity variations between the different lines of response (normalisation), (2) photon attenuation, and (3) mispositioned events due to photon scattering. These corrections must be applied to the full 3-D set of lines of response before reconstruction. The standard normalisation and attenuation correction procedures for 2-D scans increase the statistical noise in the emission scan, a problem which becomes even more serious in 3-D because of the large number of LORs involved (approximately 8 million). This paper will describe a fully 3-D reconstruction algorithm for multi-angle PET data incorporating a practical normalisation and attenuation correction procedure which minimises the increase in emission scan statistical noise. The correction factors are derived from 2-D, septa extended scans. The algorithm is currently used to reconstruct 3-D emission data from an ECAT 953B, a sixteen-ring PET camera with retractable septa.

Algorithms↗
PubMed1990

Implementation of three-dimensional image reconstruction for multi-ring positron tomographs.

In view of the number of PET studies involving low count rate acquisitions, there has been increasing interest recently in the development of positron cameras capable of fully three-dimensional acquisition and reconstruction. This interest has given impetus to the study of algorithms for 3D reconstruction, including those algorithms suitable for application to multi-ring PET scanners. While 2D reconstruction methods can often be generalised to 3D, a number of implementation problems arise which are unique to the 3D approach. This paper examines some of the difficulties associated with the generalisation of the filtered backprojection algorithm to 3D, paying particular attention to the approximations and variable transformations required for application to data from a multi-ring scanner.

Humans↗