Use of new disinfectants
The aldehyde disinfectants currently in use are irritant and sensitising but
alternatives that are safer to use may be less effective as disinfectants or may
damage endoscopes and processing equipment. If an alternative to
glutaraldehyde is to be tried, the Working Party endorses the advice given by
Babb and Bradley in 1995 (34). :
1. Inform the instrument and processing equipment manufacturers as use of
an alternative to glutaraldehyde may invalidate guarantees and/or service
contracts. (Most manufacturers are only too willing to assist and may
agree to check instruments and processing equipment periodically for
signs of damage.)
2. Carefully cost the change, bearing in mind the use life of the disinfectant.
3. Ensure that processed items are thoroughly cleaned and that the
manufacturers' stated contact times are achieved unless advice from
professional organisations is available.
4. Establish what is required in terms of COSSH regulations, ie ventilation,
personal protective clothing, and ensure that these are properly costed.
Keep the BSG, the Microbiology Advisory Committee to the Department of
Health, reference centres and disinfectant and instrument manufacturers
informed of your experience, be it favourable or not.
Unfortunately flexible endoscopes will not tolerate high processing temperatures
i.e. in excess of 60°C, and cannot therefore be autoclaved or disinfected using
hot water or subatmospheric steam. They may be sterilised, however, by other
means provided they are thoroughly clean and the manufactors' processing
criteria are met. Sterilisation options include :
Ethylene Oxide Low pressure or subatmospheric ethylene oxide sterilisers
operating at temperatures below 60°C are suitable for sterilising most flexible
endoscopes provided an EO venting cap is fitted in accordance with the
manufacturers' instructions and the instrument is suitably packaged or contained.
However, very few hospitals have an ethylene oxide steriliser. the gas is
dangerous and should only be used where suitable equipment, strict
environmental controls and specially trained staff are available. Biological
indicators are required for routine monitoring.
This process is unlikely to be suitable, if a quick turn around of instruments is
required, due to the lengthy periods (1-7 days) required for processing, the
incubation period for indicators and aeration to remove gaseous residuals.
Further advice on this method of sterilisation is contained within the Medical
Devices Agency Guidance on Decontamination of Endoscopes from the
Microbiology Advisory Committee (4).
Gas Plasma This is a highly excited body of gas produced by the application of
energy to a gas under vacuum, making ions and molecules within the plasma
collide to produce free radicles. These interact with microorganisms to disrupt
their function. The most well-known system is Sterrad TM which utilises a low
temperature <50°C) hydrogen peroxide gas plasma. The manufacturers