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IDI - Irish Decontamination Institute

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Central Service - Issue 6/2000

Central Service - Issue 6/2000


New nvCJD Cases in Britain


  • What's New in Standardisation: Sterilization Wrap
  • EFHSS: Minutes of the First General Meeting
  • Sterilisation Section of the DGKH: New Commitee
  • New UK Department of Health Documents
  • FDA Guidance on Reusing Single-Use Devices
  • British Medical Devices Agency: Negative Position on the Reuse of Medical Single-Use Devices
  • Central Service in Latvia: New Association
  • Forum 2000: Investigation of Automated Cleaning Performance
  • VSZ: The Minutes


M. Pietsch, V. Adrian, H. Haindl, A. Kramer:
Manual and Automated Processing of Tracheal Tubes Made of Silicone.
Microbiological, toxicological and physical studies

Processing of medical devices is subject to quality criteria and is to be defined according to the device. With the help of three different tracheal tubes made of silicone, an investigation was carried out to establish whether important criteria can be complied with after 100 manual or automated cleaning and disinfection cycles followed by steam sterilisation. The microbial reductions achieved by the entire processing procedure (spores of Bacillus subtilis/Bacillus stearothermophilus) in both procedures were between 7.0 - 9.1. Examination of physical parameters merely showed a low-grade reduction of elasticity of the silicone and slight shrinkage of one of the two connector materials examined. Regarding cytotoxicity and the optical impression, however, both processing procedures differed distinctly. Cytotoxic effects and unaesthetic changes in colour occurred in manual processing with an aldehyde agent from the 20th processing cycle onwards and functional problems occurred from the 80th processing cycle onwards, so that this procedure is not justifiable in principle. Occasional changes in colour could be observed in the automated procedure from the 60th cycle onwards, and from the 80th cycle onwards a cytotoxic effect or a functional impairment could be occasionally noticed. This form of processing can therefore be carried out up to 50 times.

T.J.H. Orzechowski, A.C.P. de Bruijn, C. Wassenaar:
Measurement of the Efficacy of Cleaning Procedures for Dental Handpieces.
Evaluation of an Eluation Method

Efficient cleaning is the cornerstone of infection prevention in dental practice. However, the level of the cleanliness to be achieved is a topic of discussion. The cleanliness of the outer surfaces of dental handpieces can be determined, to a degree, by visual inspection. The inner surfaces of these narrow lumen instruments do not allow visual inspection, thus other techniques must be applied. Swab tests are only partly suitable for use with hollow medical instruments, because in most cases it is impossible to swab the inner surfaces of these instruments without fully dismantling them. Even then the very narrow lumen of hollow instruments (e.g. air and water channels of dental handpieces) can never be swabbed.
In this paper a quantitative elution method is evaluated to assess the efficacy of cleaning procedures by measuring the reduction in protein contamination in artificially soiled dental handpieces.
Various process parameters were included in the study e.g. sensitivity and reproducibility With an average soiling of 411 µg/ml and a detection limit of 10 µg/ml the maximum reduction factor given by a cleaning procedure is 41. This equals a 95% reduction of the initial contamination.
The evaluation of the test principle revealed a number of problems that may not be relevant uniquely to dental handpieces, but to all kinds of medical devices of a complex construction.


50 % Time Saving at the Drying Stage of Automated Instrument Cleaning
New Procedure from Dr. Weigert, Hamburg

In automated instrument cleaning processes, the drying stage after the cleaning and thermal disinfection takes up a great deal of time and frequently takes even longer than the whole cleaning and disinfection stage. The drying time is thus mainly responsible that at times in the CSSD processing large quantities of instruments becomes almost impossible to achieve in the available time. With the newly developed rinse-aid neodisher mediklar the drying period can be reduced by 50%.


ENT Instruments/B & D Test


P. Heeg:
Infections by Rickettsia, Coxiella and Ehrlichia


Investigating the Disinfection Effect with Thermologgers

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