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Biomedical subjects

R Gähler

Publications and source records attributed to R Gähler.

11 recordsLinked to original sources
PubMed2006

Dynamics of field-induced ordering in magnetic colloids studied by new time-resolved small-angle neutron-scattering techniques.

The reversal of magnetic moments of nanoparticles in concentrated Co ferrofluids was monitored in an oscillating magnetic field by new time-resolved stroboscopic small-angle neutron-scattering techniques. Time resolution in the micros range was achieved by using a pulsed beam technique, TISANE, while in continuous mode resolution was limited by the wavelength spread to about 1 ms. The frequency dependence of anisotropic scattering patterns has been modeled using Langevin dynamics. The dynamics follows a two step mechanism: field-induced ordering is governed by fast Brownian rotation of nanoparticles with a characteristic time of about 160 micros. Magnetic relaxation of locally ordered domains of about 100 nm in size takes place within a few seconds by Brownian rotation or by Néel type rotation of magnetic moments.

Journal Article↗
PubMed1990

[Nosocomial infections in surgical intensive medicine. Results of a 5-year prospective study].

All the ICU patients were continuously studied during the first quarter of 5 consecutive years for infections according to a standard protocol. The investigators--the infection control officer and a well-trained infection control nurse--decided if the patient was infected by referring to medical and nursing record, temperature charts, laboratory and x-ray reports and, where necessary, by clinical examination. Definitions and criteria for infections comply with the CDC and the algorithms of the Senic Project. Only the first quarter of each year from 1980-1984 was analysed. The first quarter of 1980 was analysed retrospectively, the following years were examined prospectively. In 1984 a new ICU (ICU I) in addition to the old ICU (ICU II) was opened. The two ICUs differ in building construction but have similar patients, nursing staff and medical standards. The frequency of nosocomial infection was not affected by the different building constructions. The number of patients surveyed was 1009, 60% were males and 40% females. The average age was 45.5 years and the average period of stay about 4 days. 733 patients (72.6%) were intubated and artificially ventilated for 3 days. A fatal outcome resulted in 13.2% of all patients. 1129 nosocomial infections were registered in 311 patients, which means an infection rate of 32.8%. The most frequent nosocomial infections were those of the respiratory tract. Wound infections developed in 16.6%. The urinary tract was affected in 8.8%. Nosocomial septicaemias were observed in 8.7%. Catheter-associated infections were noticed in 6.7% of the patients. A fatal outcome resulted in 26% of the patients with nosocomial infections and in 6.9% of the non-infected patients, respectively.

Adult↗
PubMed1989

[Monitoring infection at the intensive care unit--a multicenter pilot study].

During a period of 3 months an infection survey was carried out in 4 intensive care units (ICUs), 2 in Vienna, Austria, and one each in Ulm and Münster, Federal Republic of Germany, using a common protocol. A total of 329 patients was monitored prospectively. This pilot study was performed to evaluate the usefulness of parameters included in the monitoring form. It was attempted to characterize the patient populations of the four units. Mean duration of stay (1-12 days), mortality (8-26%), leading diagnosis upon admission, intubation rate (41-91%) and use of pulmonary artery catheter (12-35%) were distinctly different. The rate of patients admitted already with an infection was 9-43%, septicemia was diagnosed in up to 27% of the diseased. The rate of infection acquired in the unit was between 12 and 37%, the most frequent types were bronchopneumonia, septicemia and urinary tract infection. When septicemia patients were compared to non-septicemia patients who had been admitted for more than 3 days, it appeared that the latter stayed significantly shorter at the ICU and showed less frequently bronchopneumonia or urinary tract infection at the time of admission. Septicemia patients acquired more frequently additional infections like broncho-pneumonia or urinary tract infection while staying at the ICU. The median day of onset of septicemia was the fifth day and only in a quarter of cases diagnosis could be supported by a positive blood culture. The use of antibiotics in the 4 ICUs is compared and shows marked differences. Based upon experience with this type of infection survey a new modified protocol is introduced, which displays the time course of documented events.

Anti-Bacterial Agents↗
PubMed1988

[Polytrauma and femoral fracture].

From 1976 to 1986 1.003 polytraumatized patients were treated at our institution. 88% had suffered fractures of spine, pelvis and limbs. Of particular relevance are the femoral fractures (36% of all cases) in the management of those patients. In not adequately immobilized femoral fractures the rate of general and local complications in this group is elevated. Impaired microcirculation and the required high doses of analgesics can lead to an increased risk of eventually lethal ARDS. From 1976 to 1983 we used the conventional approach and stabilized femoral fractures using plates and IM nails. Due to the time required for the operation, the eventual blood loss and the invasiveness of the operation, we could operate only on 44% of the femoral fractures within the first 24 hours. In 1984 we introduced the DAF device in our service and used it in compound femurs and unstable patients with femoral fractures. In the other cases the locking nail (GK Nail) was used. With this concept we managed to increase the rate of surgery of femoral fractures in polytrauma victims within the first 24 hours to 80%. Further assessment of the date showed a significant drop of 27.3% in mortality, mainly due to a decreased rate in late ARDS-related deaths. The advantage of the DAF concept in the stabilization of these fractures in polytrauma victims we see in the less time consuming fixation, the minimal blood loss, easier ICU care and fewer local complications. The DAF device is used as a definitive management tool and does not generally require a change to another method of fixation.

Bone Nails↗