Central Service - Issue 5/08

EDITORIAL

So what's new

NEWS UPDATE

What's New in Standardisation: Machinery
Systematic Decontamination: Techniques, Quality and Risk Containment. DGSV Members’ General Meeting and Congress, 2-4 October 2008 in Fulda

MAIN ARTICLES

F. Kramp*, F. Laugerette, V. Archer, A. Astier::
Identification of Surgical Instruments by Means of Data Matrix Codes
(Zentr Steril 2008; 16 (5): 355-363)

Abstract
The aim of our study was to evaluate the reliability of Data Matrix codes marked by means of dot-peening (DP) and laser techniques, for single identification of surgical instruments. One hundred and twenty stainless steel instruments, divided into four batches, were marked by four different suppliers, two batches by DP and three by laser, to reach a total of 204 codes marked. We followed up readability of the codes throughout the sterilisation cycles, including prolonged disinfection and immersion in caustic soda 1M. A total of 242 cycles were carried out. Code readability at the end varied between 32% and 100% depending on the suppliers. One superficial type of laser code rapidly underwent transformation and became blurred. The other types of codes did not undergo any significant corrosion- or wear-mediated transformation and thus both techniques showed excellent durability. Reading problems could be attributed to the way the marking system was set up (code size, choice of DP stylus, positioning of codes on the instrument), to the condition of the instrument surfaces and the parameter settings of the Data Matrix code reader. Aeronautical standard EN 9132 was proved to be an interesting reference source, when extrapolated to surgical instruments, to define of marking specifications.

Y. Uetera*, Y. Saito, K. Ide, H. Yasuhara, N. Kumada, R. Saito::
Investigation of "Prion" Chemical Indicators in a Prevacuum Autoclave Using a Wireless Logger System
(Zentr Steril 2008; 16 (5): 372-376)

Abstract
"Prion" chemical indicators are so designed as to discolor after the exposure of moist heat process at 134 °C for 18 minutes in the specially designed testing sterilizer (resistometer). Its cycle pattern is quite different from that of hospital autoclaves. For instance, a steam resistometer must attain the required sterilization temperature less than 10 seconds after steam introduction. In the present study, "prion" chemical indicators were evaluated in our prevacuum autoclave using a wireless logger system.
"Prion" chemical indicators of two manufacturers were used. Six pieces of each manufacturer’s indicator were placed in a reusable rigid container with the wireless logger. The container was autoclaved in our prevacuum autoclave using the routine program: three vacuum pulses, sterilization phase at 135 °C for 16 minutes and a drying time of 40 minutes. The evaluation was repeated three times. Immediately after the sterilization program was completed, the chemical indicators were inspected, and thermal evaluations were performed.
All of the "prion" chemical indicators discolored satisfactorily in all evaluations. F0 values ranged from 478 to 510. It took 2 minutes 25 seconds to 2 minutes 54 seconds for the temperature to increase from 120.0 to 134.0 °C in the come-up period. Holding time over 134 °C ranged from 15 minutes 2 seconds to 15 minutes 37 seconds with the maximum temperature from 136.1 to 136.4 °C in the sterilization phase.
The present study revealed that the "prion" chemical indicators discolored satisfactorily despite of the holding time less than 18 minutes at 134.0 °C in our prevacuum autoclave. It was also suggested that the come-up period was much longer than 10 seconds.
The present study suggested that chemical indicators should be tested using physical parameters before they are used in hospital autoclaves. It was also suggested that a wireless logger system is convenient for this purpose.

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