EFHSS Questions and Answers - Question Q00655

We have been having serious problems with cracking and crazing of plastic anaesthetic and airway equipment. We have already instigated a number of different strategies to reduce the problem. These steps were introduced one by one. Firstly we decreased the Ph from 11 to 9, followed by a decrease in temperature from 90 to 70 degrees F. There appeared to be no significant changes to the cracking of the equipment.at this early stage even though new equipment was introduced and "old' equipment was removed from circulation. Finally the rinse aide was deleted from the final rinse. Since this event, the cracking and crazing seems to have diminished quite considerably.The damaged equipment has gone to a local university to be analysed. My question is: Has anyone else had these kind of problems and if so how have they gone about finding a solution?

Dear Annett,

based on our experience with reprocessing of plastic anaesthetic and airway equipment these problems are mainly with polysulphone equipment which is not preheated by the manufacturer.

A lot of anaesthetic and airway equipment is made of polysulphone and normally this polysulphone equipment should be preheated, e.g. at 165 °C for 3 hours by the manufacturer to remove any built-in tensions. These preheated polysulphone equipment is suitable for all process chemicals like cleaner, disinfectant and rinse aids.

If polysulphone equipment is not preheated by the manufacturer, e.g. connectors of laryngeal masks, mainly rinse aids can lead to stress corrosion cracking.

Because a user likes to have the advantages of a rinse aid, e.g. a short drying time and in general a better drying of reprocessede medical devices, you should ask the manufacturer of polysulphone equipment to pre-treat his articles. In our laboratory we made a lot of test washings with rinse aids and we found out that each preheated equipment made of polysulfphone is resistant and all other not preheated polysulphone equipment will show cracks after only some wash cycles.

Kindest regards

Dr. Jürgen Staffeldt
Chemische Fabrik DR. WEIGERT GmbH & Co. KG
Anwendungstechnik neodisher
Mühlenhagen 85
D-20539 Hamburg
Tel. (49) 40 / 789 60 - 165
Fax (49) 40 / 789 60 - 123
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