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Biomedical subjects

H Rüden

Publications and source records attributed to H Rüden.

195 records · Page 11Linked to original sources
PubMed1976

[Clinical uses of ultraviolet light radiation].

The main use of ultraviolet light radiation in hospitals is for the disinfection of the air. A study was made of the disinfecting efficiency of indirect ultraviolet radiation (lifts, cleaning of bedding), direct irradiation of rooms overnight or after use, ultraviolet curtains (irradiation of the whole width of passages, doorways and entrances) and ultraviolet irradiation of the filter of air-conditioners. The results are analysed. With the exception of the barrier technique ultraviolet light irradiation did not substantially reduce the number of micro-organisms in the air. Knowledge of the limitations and side-effects of this technique, control of the intensity of ultraviolet irradiation and bacterial counts are regular intervals are some of the factors that determine the success of this mode of disinfection. Detailed studies of the acceptable upper limits of the number of micro-organisms in the air of hospital wards and operating theatres is of prime importance for evaluating the effectiveness of air-disinfection by ultraviolet light irradiation.

Air Microbiology↗
PubMed1975

[Glass fibre HEPA filters. II. Communication: Microbiological and physico-chemical researchs on used and unusued, hydrophilic and hydrophobic filter materials in an air conditioning plant (author's transl)].

Hydrophobic and hydrophilic, used and unused HEPA filters from various manufacturers, inoculated with vegetative bacteria, bacterial and fungal spores, were exposed to clean outside air for up to 17 weeks in an air conditioning plant. With relative humidities up to 60%, an increase in germ count could not be found. The rate of killing the micro-organisms inoculated were different and were generally higher on used filters. The low water content of the filter material was apparently not sufficient for microbial growth. In addition, the increase in electric conductivity and reduction of pH value resulting from deposition of substances from the outside air with an acid reaction ascertained in the aqueous filter extracts had a negative effect on the living conditions of the microorganisms.

Air Conditioning↗
PubMed1975

[Glass fibre HEPA filters. I. Communication: Microbiological and physico-chemical researchs on used and unused, hydrophobic and hydrophilic filter materials at relative humidities up to 98% in the climatic test chamber (author's transl)].

1. At high humidities up to 98%, an increase in bacteria cannot be detected. This applies to all HEPA filters investigated from the various manufacturers, independent of whether they are hydrophilic or hydrophobic, used or unused. 2. Fungal growth can only be obtained when large amounts of nutrient material (e.g. bacterial cultures) are present. In these cases a streaky growth appears . Under normal conditions of use, however, such intense contamination is not to be expected because of the prefiltration. Penetration only occurs with fungi. 3. Limitation of supply air humidity to 90% or less seems therefore to be unjustified on the basis of these investigations, if prefiltration and a satisfactory intermixing section can be guaranteed technically, and condensation is avoided. 4. HEPA filters of Grade S from various manufacturers and with different behaviour with respect to water do not allow bacterial growth even in the presence of nutrients. Additional measures for the killing of bacteria are therefore not considered necessary.

Air Conditioning↗
PubMedDate not supplied

Nosocomial and community-acquired infections in Germany. Summary of the results of the First National Prevalence Study (NIDEP)

The first German national study on the prevalence of nosocomial and community-acquired infections was performed in 1994 in medical, surgical, gynaecological/obstetrical and intensive care departments. 14,966 patients in 72 German hospitals representatively selected according to size were investigated by outside physicians. These were trained in the use of CDC definitions for nosocomial infections, and their diagnoses validated. Community-acquired infections were recorded according to the assessment of the hospital physicians. For the diagnosis of nosocomial infections, only the opinion of the outside investigators was decisive. A prevalence of 3.5% was found for nosocomial infections and 10.0% for community-acquired infections. The use of antibiotics was documented in 17.7% of all patients on the prevalence day. Of the patients undergoing antibiotic therapy, 16.9% had a nosocomial infection, 47.9% a community-acquired one. In the remaining 35.1% neither a nosocomial nor a community-acquired infection was confirmed.

Anti-Bacterial Agents↗
PubMedDate not supplied

Are nosocomial infection rates in intensive care units useful benchmark parameters?

BACKGROUND: The objectives of this study were to determine to what extent the German national nosocomial infection surveillance system (Krankenhaus Infektions Surveillance System, KISS) can take into account the circumstances prevailing in various intensive care units (ICUs) and to establish whether KISS-ICU infection rates can serve as useful benchmark parameters. METHODS: The investigation focused on three major factors: microbiological monitoring, severity of illness and the duration of surveillance. For each of these factors separate infection rates were calculated for various ICU groups and the differences compared. RESULTS: Significant differences were found for catheter-associated urinary tract infections (CAUTI) with routine monitoring, but not for ventilator-associated pneumonia (VAP). Significant differences were assessed for central venous catheter-associated bloodstream infections (CVC-BSI), considering the average ventilator utilization rate in the ICU as a surrogate parameter for the average severity of illness in its patient group. Surveillance periods of about 1 year were necessary to confirm definite outlier and nonoutlier positions for the majority of the ICUs. CONCLUSION: Using KISS data for internal orientation, it is possible to note important differences between ICUs when interpreting infection rates; some initial examples of successful use of surveillance data for the reduction of infection rates are already available. However, the use of such data for external assessment is not possible, because external observers are often unable to fully consider important factors in the interpretation of infection rates.

Benchmarking↗