Hygiene & Medizin 4/2013

Comparative study of the skin tolerability of hand disinfectants using the BUS model

W. Pittermann, C. Hildebrandt, A. Prinz, S. Lemanski, M. Kietzmann

HygMed 2013; 38 [4]:134–141

Background: No objective in vivo method has yet been established for evaluating the skin compatibility of hand disinfectants, in particular with respect to a realistic, comparative, objective and practically relevant test of the two important constituents of potential skin irritation, cell irritation and cytotoxicity. Therefore the standardized in vitro BUS (bovine udder skin) test system was implemented, enabling experiments with a mature, viable skin with intact skin barrier and reservoir functions.
Method: In the BUS skin compatibility test five approved pharmaceutical formulations of hand disinfectants (coded 01-01, 01-03, 01-05, 01-06 und 01-07) were openly applied to the skin. Distilled water was used as negative control and SLS 10% as positive control. Full-thickness skin biopsies were taken from treated as well as from untreated skin after three exposure times (30 min, 1 h and 5 h). These biopsies were then biochemically analysed with regard to their inflammatory (prostaglandin E2 concentration) and their cytotoxic (MTT-assay) potentials. In order to determine skin compatibility, the total score was computed from the sum of cytotoxicity and cell irritation values.
Results: Regarding the irritation potential of the hand disinfectants no significant differences between the formulations were observed at any exposure time. Also, there were no differences in the cytotoxic potential after 30 minutes of exposure. However, after 1 h and 5 hours of exposure, significant formulation-specific differences were found. The positive control SLS 10% and also three of the hand disinfectants reached a skin-critical score of 3.0 at one exposure time (1 h: 01-07, 5 h: 01-06) or at two exposure times (1 h and 5 h: 01-05). In contrast, neither the formulations 01-03 and 01-01 nor the negative control reached a critical cytotoxic level of a total score of 3.0.
Conclusion: The significantly better skin compatibility of the formulations 01-03 and 01-01 could possibly be explained by the lower total alcohol concentration but is primarily achieved through the use of an effective moisturizing and lipogeneous agent systems.

Keywords:
Hand disinfectants Skin compatibility In vitro assay Isolated perfused bovine udder skin model (BUS-model) Cytotoxicity Irritancy Hygienic hand disinfection

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Influence of different ventilations systems upon the contamination of medical devices

T. Benen, F. Wille, L. Clausdorff

HygMed 2013; 38 [4]:142–146

Background: The sterility of the medical devices used in an operating rooms (OR) is one main aspect to avoid surgical site infections. This study analyzed the influence of different ventilations situations according the contamination of the medical devices.
Method: We analyzed laminar airflow ceilings (LAF) size 3.2 m x 3.2 m (Ia-OR) and turbulent ventilation systems (Ib-OR). The Ia-OR was successfully qualified with the protection degree measurement according the DIN 1946-4: 2008. The Ib-OR was qualified with a recovery test. Within the Ia-OR additional measurements were done outside of the protected area of the LAF to show the importance of this area.
Results: The results show a dependency between the contamination of the medical devices and the kind of ventilation system. The medical devices in the Ib-OR and out of the protection area are contaminated more often and with more germs than within the protection area under the laf.
Discussion: It has to be questioned if under these ventilations systems the requirements of the medical device guideline (KRINKO/BfArM-guideline) are fulfilled. The sterility of the medical devices until its use is one main aspect of this guideline. With this study we want to focus one until now rarely observed point of the intrasurgical medical device contamination.

Keywords:
Surgical site infections LAF Ia-OR Ib-OR Medical device contamination

Inactivation of exhaust air filters in ventilation systems of high safety laboratories: process validation using vaporized hydrogen peroxide

D. Reichenbacher, M. Thanheiser, U. J. Weber, D. Krüger

HygMed 2013; 38 [4]:147–151

A successful performance based on documented evidence proving the effectiveness of process was demonstrated for the inactivation of an H 14 HEPA-filter combination in a biosafety laboratory ventilation system. Vaporized hydrogen peroxide was used as a decontaminant to inactivate all components of filter housing and filters. Using a test aerosol it was possible to inspect the installed filters and to check the filtration efficiency. However, when filter replacing is indicated, there is a requirement to inactivate prior to disposal. As usual for room decontamination, the process can be controlled quantitatively and qualitatively with chemical and biological indicators. A detailed documentation of the testing procedures and their results can be the basis for a standard operation procedure. Nevertheless, changing of any essential process parameter necessitates repeated validation. Finally, an overview is given on the requirements under §18 of the German Law on the Prevention of Infection concerning room decontamination.

Keywords:
HEPA-filter inactivation Process validation Vaporized hydrogen peroxide