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Biomedical subjects

W Dorda

Publications and source records attributed to W Dorda.

At least 19 recordsLinked to original sources
PubMed2004

The strategic approach of managing healthcare data exchange in Austria.

OBJECTIVES: The exchange of electronic medical data between healthcare providers constitutes an integral part of modern medicine, and its importance is growing. Efficient application on a national level requires a uniform approach to the management of healthcare data exchange, avoiding isolated solutions that are expensive and also incompatible. METHODS: In this communication we explain the basic concepts of establishing a nationwide framework to guide healthcare data exchange in Austria. To achieve this goal, a three-step approach was adopted: (i) creating general guidelines to direct electronic medical data exchange; (ii) defining detailed standards for electronic messages; (iii) organizing pilot projects to implement these standards, and further improving the general guidelines based on the results of the pilot projects. RESULTS: We present the MAGDA-LENA framework which guides healthcare data exchange in Austria, and compare it with the US framework HIPAA. We describe several communication scenarios for which concrete message standards were developed in recent years, based on the MAGDA-LENA framework. We further discuss the implementation of these standards in four pilot projects. CONCLUSIONS: The strategic approach of managing healthcare data exchange presented in this paper is expected to have a substantial impact on medical informatics in Austria over the next few years.

Austria↗
PubMed2002

Clinical data retrieval: 25 years of temporal query management at the University of Vienna Medical School.

OBJECTIVES: Today, many clinical information systems include analysis components which allow clinicians to apply a selection of predefined statistical functions that satisfy typical cases. They are mostly to inflexible to handle complex, non-standard problems, however. The focus of this paper, therefore, is to present an approach that enables clinicians to autonomously create ad hoc queries including temporal relations in an interactive environment. METHODS: We developed the query language AMAS, which was specifically customized for users from the medical domain to flexibly retrieve and interpret temporal, clinical data. AMAS provides for a significant temporal expressiveness in data retrieval using time-stamped clinical databases and relies on an operator-operand concept for the specification of a query. RESULTS: Within the last 25 years, four different clinical retrieval systems have been implemented at the Department of Medical Computer Sciences, based on the AMAS query language. Currently, these systems allow access to the medical records of more than 2 million patients. Physicians of 46 different departments at the University of Vienna and Graz Medical Schools have made extensive use of these systems in the course of clinical research and patient care, executing more than 10,000 queries per year. CONCLUSIONS: We discuss a list of 20 issues that represent the most essential lessons we have learned in the development of the four systems mentioned above. Amongst others, our experiences indicate that the operator-operand concept allows on intuitive specification of complex, temporal queries. Further, customization to different user classes, based on their statistical background, is essential.

Austria↗
PubMed2001

Moving time window aggregates over patient histories.

Moving window concepts are used in temporal query languages for aggregate functions over the dimension 'time'. In the medical domain, aggregation of patient data over time windows builds a powerful mechanism within clinical database queries to satisfy a class of typical medical question formulations. Contrary to other fields, like the business domain for example, there is the additional need to synchronize time windows with the individual course of diseases rather than with the calendar system only. In this paper, we present several variants of shifting time windows over patient histories and suggest a set of essential options for a moving window clause. The proposed parameters for window creation as well as suitable default settings are discussed in the context of retrieving data from medical records.

Databases as Topic↗
PubMed2000

Unambiguous identification of hospital patients: case study at the university departments of the General Hospital, Vienna.

This article considers the problem of identifying patients in one or more heterogeneous personal databases. The unambiguous identification of patients is an essential prerequisite for an efficient patient care system. We discuss the problems involved in this task and suggest how they can be dealt with. The solution of automatic consolidation of patient records sequires programming, organisational and work psychology measures. Following a survey of conventional identification methods, the method developed at the Department of Medical Computer Sciences, which is based on the current clinical situation at the General Hospital in Vienna (AKH--Allgemeines KrankenHaus), is described in detail. The basic principle is to identify patients unambiguously by means of an ID (IZAHL) derived directly from the personal data. Thereby a deterministic technique without probability weighting is used-all compared information must correspond completely. The article closes with a critical survey of experience gathered to date.

Algorithms↗
PubMed1999

ArchiMed: a medical information and retrieval system.

ArchiMed is a highly flexible medical data storage and retrieval system which adds sophisticated clinical research support to a standard hospital information system (HIS). Currently, the HIS of Vienna General Hospital-University Hospital (2000 beds) stores the clinical data of over 2 million patients. While this system supports patient care (e.g., ADT, clinical chemistry, diagnosis, procedures), it has no features to facilitate research, such as the management of clinical studies. ArchiMed is designed to support clinical research. It includes an independent database, which mirrors virtually all the information held in the HIS while also allowing new data to be collected independently and to be added to the database. Flexible retrieval and analysis of data contained in the database are then possible. Thus, existing patient data can be smoothly incorporated into a study together with data collected specifically for research purposes. The system has already been successfully installed in the departments of surgery and soon in other departments as well.

Austria↗
PubMed1996

Lymphoproliferative responses to Borrelia burgdorferi in circumscribed scleroderma.

Humoral immune responses to Borrelia burgdorferi (Bb) have been reported to occur in certain patients with circumscribed scleroderma (CS) (morphoea). Together with the isolation of spirochaetes from CS skin biopsies, this finding was taken to suggest Bb as the aetiological agent of CS. Since there is cellular immunoreactivity to Bb in patients with chronic Lyme borreliosis (LB), Bb-specific lymphocytic responses were tested in patients with CS. For this purpose, peripheral blood mononuclear cells from CS patients and, as controls, from patients with various manifestations of LB, and from healthy volunteers without any evidence of Bb infection, were exposed to Bb organisms for 5 days and then assayed for DNA synthesis. Stimulation indices (SI) > 10 were scored positive. By performing lymphocyte proliferation tests we found: (i) that not only patients with various manifestations of LB but also a considerable percentage of seropositive (five of 13 = 38%) and seronegative (six of 26 = 23%) CS patients exhibit an elevated Bb-induced lymphocyte proliferation; (ii) that the magnitude of the cellular response seen in CS patients is comparable to that encountered in patients with established Bb manifestations; and (iii) that, within a given patient, antibiotic therapy can result in a significant reduction of this response. These results support a causative role of Bb in at least some CS patients. Bb-induced lymphocyte responses were also seen in both seropositive and seronegative erythema chronicum migrans patients. These findings show that the pattern of Bb-specific immune responses is more complex than previously thought, and underscore the importance of lymphocyte function assays in evaluating the diagnosis of potential Bb infection in seronegative patients.

Adolescent↗
PubMed1995

[Isosorbide-5-mononitrate in silent ischemia].

Thirty six patients with documented coronary artery disease and exercise-induced silent ischemia were evaluated in a double-blind randomised placebo-controlled crossover study. The effect of once daily 60 mg sustained-release isosorbide-5-mononitrate (IS-5-MN) was tested on exercise-induced and ambulatory silent ischemia. After a wash-out period in which no cardioactive drugs were administered, each patient received IS-5-MN for the first week, followed by placebo for the second week, or vice versa. A symptom-limited bicycle exercise test and Holter monitoring over a 24-hour period were performed after wash-out and at the end of each one-week treatment period. In comparison with wash-out IS-5-MN significantly (p < 0.05) prolonged time on onset of 1 mm ST-segment depression during exercise testing. On the other hand, the number and circadian variation of ischemic episodes during Holter monitoring were not influenced by IS-5-MN. Thus, 60 mg IS-5-MN once daily significantly improved silent ischemia during exercise testing but not during Holter monitoring. This discrepancy may be due to different pathogenetic mechanisms of ischemia during ergometry as opposed to the everyday situation; nitrates may also provoke silent ischemia by increasing the heart rate. Furthermore, the choice of only one antiischemic drug at a fixed dosage may not be aggressive enough in suppressing ischemia completely.

Adult↗
PubMed1989

[Critical evaluation of fructosamine as a control parameter in the assessment of diabetic metabolic regulation].

For some years the glycosylated plasma proteins, the so-called fructosamines, have been used for the evaluation of metabolic control in diabetic patients. We studied the usefulness of fructosamine as an intermediate parameter in the control of diabetes and we also corrected fructosamine for serum protein. Furthermore, the dependence on daily times and amounts of food intake were examined for fructosamine alone as well as for protein-corrected fructosamine. Both parameters showed a statistically significant correlation with HbA1C (r = 0.7; P less than 0.001). Changes in the metabolic state of the diabetic patients were reflected more rapidly by both these parameters than by HbA1C. While the correction of fructosamine for serum protein eliminated its postprandial increase in the diabetic patients, circadian variation remained unchanged.

Adolescent↗
PubMed1987

[Use of the computer in clinical medicine].

This article describes the application of computers in clinical medicine and the experience gained by the Institute of Medical Computer Science when introducing computer systems into the clinics of the University of Vienna Medical School in the last 20 years. It is shown what dramatic development has taken place in these years. The medical information system WAMIS with its central patient database is described as well as the medical record keeping documentation and retrieval system WAREL, which is destined to analyze medical natural language data. A further chapter deals with computers in clinical laboratories. At the end it is tried to point out future trends in applying computers in clinical medicine.

Austria↗
PubMed1986

Model for estimation of clinically achievable plasma concentrations for investigational anticancer drugs in man.

A major problem related to in vitro testing of new investigational anticancer compounds is the lack of accurate pharmacokinetic data for the drugs in man. Based on the concept of a relationship between certain toxicologic endpoints in animal systems and maximally tolerated doses in man, we hypothesized that a comparable agreement might exist between these experimental animal toxicology data and clinically achievable peak plasma concentrations (PPCs). A retrospective analysis of the known data pairs of 28 commonly used cytotoxic compounds supports the existence of a reasonably good correlation between ip LD50 values (Pearson test) in nontumored mice and PPCs in man (r2 = 0.501; P less than 0.0001). Our data suggest that by use of the resultant statistical regression model a rational starting point can be selected for in vitro screening of entirely new agents for which human PPCs are not available. Additionally, application of this approach may also prove useful in relation to selecting in vitro doses for chemosensitivity assays intended for predictive correlation with clinical response in cancer patients.

Animals↗
PubMed1985

[Effect of body size, arm length, sex and temperature on somatosensory evoked potential latency].

Beside the technical factors different biological factors contribute to the variability of the somatosensoric evoked potentials. In 30 volunteers the dependence of the latency of the spinal components N9, N13 (recorded at C7), of the cortical component N20 and of the interpeak interval N13-N20 from the body size and length of the arm was investigated. A significant dependence at the 1% level (p less than 0.001) was found for the latencies of N9, N13 and N20, whereas the interpeak interval N13-N20 was significant at the 5% level (p less than 0.05). Similarly in 20 further volunteers a significant dependence of the components N1, P1, N2, P2 and N3 from the body size at the 1% (p less than 0.001) after distal stimulation of the tibial nerve was observed. Using a covariance analysis it could be shown, that even after a body size correction, in females shorter latencies occur than in males. Furtheron we studied the effect of the temperature on the SSEP-latencies, by heating the upper and lower extremity stepwise from 31 degrees C to 37 degrees C using an infrared (DISA-Regler-System) lamp. As no significant dependence could be observed, we believe that the effect of temperature on latencies is so small, that in usual conditions no correction is needed. On the contrary a correction with body size or arm length is necessary, to avoid wrong positive or negative results.

Adult↗
PubMed1985

[Incidence of identification and configuration variants of the NSEP signal in relation to the recording site and measuring moment].

The component evaluation of the spinal and cortical recorded SEP-signals of thirty healthy volunteers after stimulation of the median nerve at the wrist gave information about variation of waveforms and frequency of peak identification with respect to the position of the active electrode and the repetition of the SEP recording. Basically one can distinguish three main groups of NSEP waveforms (Fig. 1). Firstly the "classical form" (i.e. N11 in the ascending part, N13 at the highest peak of the NSEP main component and N14 in the descending part of the curve). Secondly the "plateau-form" and thirdly the "polypeak form" (i.e. many peaks of the same amplitude). The latter two configurations were seen in more than a third of the evaluated NSEP maincomponents. Neither the position of the active electrode (C2 and C7) nor repetition of the SEP recording were found to have significant influence on the waveform. The position of the active electrode influenced the number of identificable peaks: the early components (N9 and N11) were more often recognisable when the recording was made over the lower neckregion (C7), N14 when the recording was made over the upper neckregion (C2). N13 was always identificable in both electrode positions. The repetition of the SEP recordings immediately after the first run is helpful if there was difficulty in identifying the peaks. The normal values of the SEP latency of the spinal and cortical recorded signals were evaluated taking above mentioned criteria into account.

Adult↗
PubMed1984

Changes of the corneal endothelium following intracapsular cataract extraction with implantation of semiflexible anterior chamber lenses. I. Results of the early post-operative period.

A consecutive group of 103 patients with senile cataract underwent intracapsular cataract extraction and implantation of a semiflexible anterior chamber lens. After 6 month of follow-up, there was an average decrease of 20% +/- 15% in central corneal endothelial cell density and an average vertical disparity of 32% +/- 20% between central and superior endothelial areas. The endothelial cell loss was not correlated with pre-operative cell density. There was a positive correlation between age and cell loss and between age and vertical disparity. Findings in eyes with cornea guttata did not differ significantly from those without guttata. Anterior vitrectomy did not increase endothelial cell loss significantly. Maintenance of a deep anterior chamber by pre-operative oculopression or by instillation of Na-hyaluranate had no significantly different effect on the corneal endothelial cell loss.

Adult↗
PubMed1983

[Somatosensory evoked potentials: normal values and methodological problems in various recording technics].

In order to optimize the method of examination, somatosensory evoked potentials (SSEP) were studied in 27 healthy subjects, as recorded during stimulation of the median nerve at the wrist. The study shows that recordings with surface electrodes produced better results than with needle electrodes, owing to lesser disturbance from muscle artifacts. The SSEPs of each subject were recorded taking a fixed position of the active electrode placed over the contralateral sensory "hand field", and a reference electrode positioned for the first recording mid-frontally and for the second recording at the contralateral ear or vice versa. The first 3 positive and the first 3 negative peaks were studied. Exact identification of each peak was more often possible when recordings were made with the reference electrode placed mid-frontally than placed at the contralateral er. Normal values were evaluated for the latency P15, P25, P45, N30, N35 and N55, for the amplitudes P15-N20, N20-P25, P25-N35, N35-P45 and P45-N55 and for the latency intervals P15-N20, N20-N35, N35-N55, P15-P25 and P25-P45, with the reference electrode in different positions. In addition, the side difference for each subject was determined. Statistical analysis (T-test for independent variables) revealed a significant difference, depending on the position of the reference electrode: with the reference electrode placed at the contralateral ear, the latency P15 was shorter, the amplitude P15-N20 was increased and the amplitude N20-P25 was decreased as compared with a reference electrode placed mid-frontally.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

The effect of timolol on the concentrations of albumin and IgG in the aqueous humor of the human eye.

We investigated albumin and IgG concentrations in the aqueous humor of 41 patients before intracapsular cataract extraction (primary samples) and at the end of surgery (secondary samples). Albumin and IgG concentrations were determined in all samples by means of a quantitative fluoroimmunoassay. A short-term topical application of timolol in 24 eyes was associated with a significant increase in both proteins in the primary aqueous humor samples compared with 17 control samples (P less than .005). The ratios of albumin to IgG--even when corrected for serum levels--were not significantly different in the two groups. Timolol did not affect the change in these ratios in the secondary aqueous humor samples. Thus, we concluded that these findings were not caused by a breakdown of the blood-aqueous barrier, but rather resulted from reduced aqueous humor flow and undisturbed protein filtration.

Aged↗
PubMed1982

[Diagnostic key for intensive care patients: combination of clinical parameters with laboratory findings].

A new diagnostic key has been established based on the reports of 3845 critically ill patients in our medical intensive care unit. The clinical diagnoses in these patients were classified in 22 different groups according to different organs or etiological entities (diseases of the liver, infectious diseases, intoxications etc.). 42 different laboratory parameters were selected for classification of metabolic or organ-related complications. Combining of clinical diagnoses with laboratory values characterizes the seriously ill patient. Our new system proved to be practicable in describing the degree, complications and prognosis of disorders in intensive care medicine. The results are demonstrated in patients with hepatic coma.

Clinical Laboratory Techniques↗