Central Service - Issue 5/04

EDITORIAL

A Few Words of Greeting at the DGSV Congress in Potsdam

NEWS UPDATE

What's New in Standardisation: Product Families
Quality - a Dynamic Process. DGSV Annual Meeting and Congress in Potsdam
International Association of Healthcare Central Service Materiel Management. Annual Meeting Summary
Canadian Ministry of Health Warns Hospitals against Reuse of Single-Use Devices
Commentary by the Authors of the Brochure: "Practical Guide to Validation of Cleaning and Disinfection Processes"

MAIN ARTICLES

U. Borchers*, M. Mielke:
How Material, Length, Wall Thickness and Diameter of Hollow Devices Affect the Inactivation Behaviour of Biological Indicators when Subjected to Moist-Heat Treatment
(Zentr Steril 2004; 12 (5): 314-323.)

Abstract
Hollow device test models are needed when validating medical device processing procedures. This paper outlines how the diverse materials and geometries of hollow process challenge devices (PCDs) affect the inactivation behaviour evinced by biological indicators when subjected to moist-heat treatment. The biological indicators used were 1-cm long quartz glass threads that had been contaminated with a spore suspension of Bac. atrophaeus (formerly: Bacillus subtilis var. globigii). Compared with paper germ carriers, quartz glass carriers have the advantage that they do not give rise to overheating phenomena and to the attendant distortion of results (1, 2, 3, 4). A further advantage resides in the fact that they can be used for devices with lumens > 1 mm. The biological indicators were placed directly at the closed end of the PCD, in order to avoid as far as possible any effect that would be generated by the receptacle on the results, due to its large mass, different material composition or geometric shape. The PCDs were subjected under similar conditions to a pulsed vacuum procedure (100-1000mbar) using up to 10 pressure surges. The exposure temperature was 100°C for 5 min.
It was revealed that it is easier to inactivate biological indicators in silicone hoses than those in PTFE hoses or stainless steel pipes. In the tests carried out, PTFE hoses proved to be the most difficult. The relationship between length and microbial count reduction was inversely proportional. The internal diameter of the hose or pipe also exerts an influence on the effectiveness of the steam process. The larger the internal diameter, the more difficult it is to reduce the microbial load in the biological indicators, but with only a minor difference seen between 6 and 8mm. Whereas it was easier to inactivate biological indicators in silicone hoses the smaller the wall thickness, a paradox effect was noted in PTFE hoses for a wall thickness greater than 1 mm. Hence hollow PCDs as described in DIN EN 867-5 did not prove to be the most difficult PCDs to treat.

W. Michels*, M. Pieper:
Characteristics of Blood and their Influence on Cleaning Processes
(Zentr Steril 2004; 12 (5): 324-330.)

Abstract
Blood is a particularly frequent contaminant of surgical instruments, and one that is highly relevant to the technical aspects of cleaning. It is therefore necessary to take into account the characteristics of blood when designing automatic temperature-controlled processes, and to choose the process parameters in such a way as to rule out those predictable effects that would impair results. These experiments investigate the denaturation of and changes in blood as they depend on temperature, as well as on alkalinity. Here use is made of the visible colour changes in haemoglobin, which imply that there is also a change in the UV spectrometric measurements.

R. Busch:
Certification of the CSSD on the Basis of the RKI Recommendation. A report of experience from Klinikum Weiden

A. Brusa*, V. Rigobello, O. Mauriziano, A. Ospedaliera:
Experience with a new routine monitoring system for steam sterilization processes standardized in EN 867-5 as Hollow A test system

RECOMMENDATIONS BY THE QUALITY TASK GROUP (AK »QUALITÄT«)

Risk Management in the CSSD