Ethylene Oxide sterilisation breaks the four hour barrier
08 June 2009
Ethylene Oxide (EtO) has been used as a sterilant for nearly eighty years now. It has stood the test of time as a very effective sterilant, being good both at killing a wide range of pathogens and at sterilising the most complex shapes.
It continues to be a major technology for the sterilisation of medical devices world wide. Indeed, if you look at the back of packages containing devices for use in surgery some 70% contain the statement “Sterile EO”.
The majority of medical devices sterilised by EtO are designed for single use. The insight of Dr Andersen in the 1960's was to deliver the EtO directly to the heart of the load, in a glass ampoule. This allowed sterilisation to be achieved without any of the compressed gas cylinders, steam lines or compressed air required by traditional, large EtO chambers. It also allowed sterilisation to be achieved with a small fraction of the EtO used by other technologies. In short EtO sterilisation became accessible to hospitals and clinics. They could do their own EtO gas sterilisation in their own facility, opening a whole new world for re-sterilisation of medical devices.
The challenge for EtO as a technology remained the time required for a sterilisation cycle. Even in the Andersen chambers a cycle would typically be run overnight. There was also the requirement for aeration before devices could be used on a patient. It is a feature of EtO that it is absorbed by many materials, particularly soft plastic, and this may need to elute before a device can be re-used.
The latest EtO steriliser from Andersen Products is the Series 4. This delivers the benchmark 10-6 sterility assurance level in 3½ hours. Furthermore, as this cabinet runs at 50ºC the items can be left in the cabinet for a further hour to drive off residual EtO. The result is that EtO sterilisation now delivers all items sterilised and ready for use in 4½ hours. This highly efficient steriliser gives users the ability to use the most effective sterilant and reuse their delicate and expensive equipment again the same day.
