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T Hauer

Publications and source records attributed to T Hauer.

At least 19 recordsLinked to original sources
PubMed2006

Experiences of engineering Grid-based medical software.

OBJECTIVES: Grid-based technologies are emerging as potential solutions for managing and collaborating distributed resources in the biomedical domain. Few examples exist, however, of successful implementations of Grid-enabled medical systems and even fewer have been deployed for evaluation in practice. The objective of this paper is to evaluate the use in clinical practice of a Grid-based imaging prototype and to establish directions for engineering future medical Grid developments and their subsequent deployment. METHOD: The MammoGrid project has deployed a prototype system for clinicians using the Grid as its information infrastructure. To assist in the specification of the system requirements (and for the first time in healthgrid applications), use-case modelling has been carried out in close collaboration with clinicians and radiologists who had no prior experience of this modelling technique. A critical qualitative and, where possible, quantitative analysis of the MammoGrid prototype is presented leading to a set of recommendations from the delivery of the first deployed Grid-based medical imaging application. RESULTS: We report critically on the application of software engineering techniques in the specification and implementation of the MammoGrid project and show that use-case modelling is a suitable vehicle for representing medical requirements and for communicating effectively with the clinical community. This paper also discusses the practical advantages and limitations of applying the Grid to real-life clinical applications and presents the consequent lessons learned. CONCLUSIONS: The work presented in this paper demonstrates that given suitable commitment from collaborating radiologists it is practical to deploy in practice medical imaging analysis applications using the Grid but that standardization in and stability of the Grid software is a necessary pre-requisite for successful healthgrids. The MammoGrid prototype has therefore paved the way for further advanced Grid-based deployments in the medical and biomedical domains.

Humans↗
PubMed2005

Resolving clinicians' queries across a Grid's infrastructure.

OBJECTIVES: The past decade has witnessed order of magnitude increases in computing power, data storage capacity and network speed, giving birth to applications which may handle large data volumes of increased complexity, distributed over the internet. METHODS: Medical image analysis is one of the areas for which this unique opportunity likely brings revolutionary advances both for the scientist's research study and the clinician's everyday work. Grids [1] computing promises to resolve many of the difficulties in facilitating medical image analysis to allow radiologists to collaborate without having to co-locate. RESULTS: The EU-funded MammoGrid project [2] aims to investigate the feasibility of developing a Grid-enabled European database of mammograms and provide an information infrastructure which federates multiple mammogram databases. This will enable clinicians to develop new common, collaborative and co-operative approaches to the analysis of mammographic data. CONCLUSION: This paper focuses on one of the key requirements for large-scale distributed mammogram analysis: resolving queries across a grid-connected federation of images.

Algorithms↗
PubMed2002

[Reliable and unreliable health measures in surgery].

Despite high standards in theatre design, surgical skills and antibiotic prophylaxis, surgical site infections are still a major complication in modern surgery. After urinary tract infections and lower respiratory tract infections they account for 15.8% of all nosocomial infections in Germany [31]. Causes are multiple and only partially exogenous. The single most important (exogenous) risk factor is the technical skill of the surgeon. Not all surgical site infections are therefore preventable by infection control measures alone. Useful and useless infection control measures will be evaluated critically in the following review according to data in the literature.

Air Microbiology↗
PubMed2000

[Reasonable and unreasonable hygiene measures in anesthesia in the intensive care unit].

The objective of this review is to describe which hygiene measures are appropriate and necessary in anaesthesia and the ICU and which are not, whereby unnecessary hygiene measures are those which are not substantiated by scientific data. The most effective single infection control measure is still hand disinfection between patient contacts. Unnecessary measures include routine sampling of environmental surfaces, disinfecting the floor in the ICU, protective gowns for visitors, so called in-line filters in the infusion system etc. Ventilator tubes only need to be exchanged once a week, even when no HMEs are used.

Anesthesia↗
PubMed2000

Aerators as a reservoir of Acinetobacter junii: an outbreak of bacteraemia in paediatric oncology patients.

Tap water can play a role as a source of nosocomial pathogens, and faucet aerators have occasionally been mentioned in the literature associated with colonization or infection in hospitalized patients. In this study, we report on outbreak of bacteraemia in paediatric oncology patients caused by Acinetobacter junii. Environmental sampling showed the water system to be contaminated with A. junii. Molecular typing using automatic laser fluorescence analysis of randomly amplified polymorphic DNA (RAPD-ALFA) revealed two distinct strains. The outbreak strain, isolated from blood cultures of the affected children, was only found in the water taps of staff rooms. Aerators were commonly found to be contaminated, and more so than water obtained after removal of these devices. We believe that conventional aerators consisting of several wire meshes can serve as a reservoir for low levels of bacteria present in the water system. We recommend, especially for high-risk areas, either that aerators should not be used, or the use of aerators consisting of radially and vertically arranged lamellae, which do not lead to the collection of sediment or water stagnation, and to clean them regularly.

Acinetobacter↗
PubMed1999

Comparison of effectiveness and required time of two surveillance methods in intensive care patients.

The intensive care unit (ICU) standardized protocol of the NNIS (National Nosocomial Infections Surveillance) system is a surveillance method of hospital acquired infections (HAI), which provides device-associated infection rates. The aim of this study was to assess the effectiveness and the required time for data collection and analysis of a selective surveillance method (SSM) derived from the NNIS ICU surveillance protocol, and to compare its data with that of a reference surveillance method (RSM). The sensitivity, specificity and the positive predictive value (PPV) of the RSM were 87.5, 100 and 100%, respectively. The sensitivity, specificity and the PPV of the SSM were 59.4 97.6 and 79.2%, respectively. Considering device-related infections only (ventilator-related pneumonia, catheter-related urinary tract infections, central line-related sepsis), the sensitivities of the RSM and the SSM were 80.9 and 90.5%, respectively. The SSM required only one third of the time of the RSM (1.1 h and 3.4 h per 10 beds per week with the SSM and the RSM, respectively). We conclude that the SSM has a very high sensitivity for detecting device associated infections, but is not sensitive enough for surveying all types of HAI.

Cross Infection↗
PubMed1999

How many nosocomial infections are missed if identification is restricted to patients with either microbiology reports or antibiotic administration?

OBJECTIVE: To investigate how many nosocomial infections would be missed if surveillance activities were restricted to patients having either microbiology reports or antibiotic administration. DESIGN: Analysis of data from a large prevalence study on nosocomial infections (Nosocomial Infections in Germany-Surveillance and Prevention). SETTING: A total of 14,966 patients were investigated in medical, surgical, obstetric-gynecologic, and intensive-care units of 72 German hospitals representatively selected according to size. Five hundred eighteen patients (3.5%) had at least one nosocomial infection. Microbiology reports were available for 56.6% of these patients on the prevalence day, and 86.3% received antibiotics. RESULTS: Only 31 nosocomially infected patients (6%) would have been missed by using either microbiology reports or antibiotic treatment as an indicator. These indicators of nosocomial infections had a high diagnostic sensitivity for nosocomial pneumonia (98.8%), urinary tract infections (96.3%), and primary bloodstream infections (95.3%), but a lower sensitivity for wound infections (85.4%). Thus, 97.4% of all nosocomial infections were found with this method in intensive-care units and 96.1% in medicine units, but only 89.7% in surgical departments. In 9 (12.5%) of 72 hospitals, the overall sensitivity would have been <80% using a combination of the two indicators. For this reason, the situation in one's own hospital should be checked before using this method. CONCLUSIONS: After checking the situation in one's own hospital, the "either-or" approach using the two indicators "microbiology report" and "antibiotic administration" can be recommended as a time-saving measure to diagnose pneumonia, urinary tract, and primary bloodstream infections. For wound infections, additional information obtained by changing dressings or participating in ward rounds is necessary to achieve satisfactory sensitivity in the surveillance of nosocomial infections. Of course, it is necessary that the surveillance staff discard all false positives to ensure a satisfactory specificity.

Anti-Bacterial Agents↗
PubMed1998

[Requirements of mandatory accident insurance for hospitals, which participate in inpatient treatment of occupational accident patients: position of the National Reference Center for Hospital Hygiene].

Aseptic operations as well as operations on infected sites can be done in the same operating room. Two or more theatres can share common facilities such as X-ray equipment, scrub-up or anaesthesia areas. Sophisticated air locks with double doors, which separate the protective zone from the operating room are not necessary to maintain a good hygienic standard. Nevertheless the new requirements for theatre design by the German "Gesetzliche Unfallversicherungen" are much higher. In this commentary we try to summarize scientific evidence regarding design of a theatre and infection control.

Accidents, Occupational↗
PubMed1998

Prevalence of nosocomial infections in representative German hospitals.

The nosocomial infection (NI) rate in German hospitals was studied in order to create reference data for comparison in hospitals where ongoing surveillance is impossible. The study was designed as a one-day prevalence study. Patients in 72 selected hospitals (inclusion criteria: acute care hospitals with departments for general medicine, surgery, obstetrics/gynaecology) were examined by four external investigators (physicians trained and validated in the diagnosis of NI). A total of 14,996 patients were studied. The overall prevalence rate was 3.5% (CI 3.1-3.9) with a variation of 0-8.9% between hospitals. The commonest NI were: urinary tract infection (42.1%), lower respiratory tract infection (20.6%), surgical site infections (15.8%) and primary sepsis (8.3%). The highest prevalence rate (15.3%) was found in intensive care ward patients, followed by surgery (3.8%), general medicine (3.0%) and gynaecology/obstetrics (1.4%). The infection rate varied significantly with hospital size. A microbiology laboratory report was only available for 56.5% of patients thought to have an NI, and there were remarkable differences between hospitals with and without an on-site microbiology laboratory. Because of this and other methodological reasons the NI prevalence rates reported here may represent the absolute minimum of nosocomially infected patients in Germany.

Cross Infection↗
PubMed1998

Experience with two validation methods in a prevalence survey on nosocomial infections.

OBJECTIVE: To determine whether an investigator effect remained on the first German study on the prevalence of nosocomial infections Nosokomiale Infektionen in Deutschland Erfassung und Prävention (NIDEP), despite extensive validation efforts. DESIGN: Two validation methods were applied: bedside validation and validation by case studies. In both cases, the results of the four investigators were compared with the diagnosis of gold standard observers. SETTING: Validation measures were applied before, intermittently, during, and at the end of the surveillance period in 72 acute-care hospitals with 14,966 patients. RESULTS: The overall sensitivity in the bedside-validation periods was 89.0%; the overall specificity was 99.5%. For validation by case studies, overall sensitivity was 95.6%, and overall specificity was 92.8%. At the end of the surveillance, a remarkable investigator effect was found. CONCLUSION: Despite validation results that were assessed as satisfactory, based on available literature, an investigator effect was observed. This underlines the need for data validation and the formulation of recommendations for data validation. Clarification of the Centers for Disease Control and Prevention criteria for pneumonia and primary bloodstream infection and the inclusion of some diagnostic test results may reduce or prevent an investigator effect in future studies.

Bias↗
PubMed1996

[Nosocomial infections in Germany. Microbiological diagnosis, preventive antibiotics and antibiotic therapy].

BACKGROUND: The NIDEP-study (Nosocomial Infections in Germany-Prevalence and Prevention) is the first large multicenter survey to examine the prevalence of nosocomial infections (NI) in Germany. This part of the NIDEP-study describes the frequency and quality of the microbiological diagnosis, antimicrobial chemoprophylaxis and therapy in representative German hospitals. PATIENTS AND METHOD: Prevalence of nosocomial infections in 14 966 patients of 72 randomly selected representative German hospitals was determined. Frequency, nature and results of the microbiological diagnosis, antimicrobial chemoprophylaxis and therapy were recorded simultaneously. RESULTS: The total prevalence rate of nosocomial infections was 3.5%. The most common infections were urinary tract infections (42.1%), lower respiratory tract infections (20.6%), postoperative wound infections (15.8%), and septicemia (8.3%). Microbiological evaluation was done in 56.5% of the patients with infections. Only five of the 49 hospitals with less than 400 beds and only nine of the 23 hospitals with more than 400 beds had their own microbiological department. Antimicrobial chemotherapy was administered in 17.7% of the patients. In 35.1% of the patients who were treated with antibiotics, no clinical diagnosis of infection was made, criteria for nosocomial infections were not fulfilled or microbiological evaluation was not established. Antimicrobial chemoprophylaxis was done in one third of the patients. Prophylaxis was missed in 20.6% of patients with colorectal operations, 60.1% of appendectomies, 48% of vaginal hysterectomies, and 35.5% of total hip replacements. On the other hand antimicrobial chemoprophylaxis was frequently administered in clean procedures without increased risk of postoperative wound infections. CONCLUSION: Insufficient microbiological evaluation, inadequate perioperative antimicrobial chemoprophylaxis and administration of chemotherapy without documented infection were detected in representative German hospitals.

Anti-Bacterial Agents↗