Ethylene Oxide (ETO) sterilisation is a process used to sanitise and disinfect a variety of temperature-sensitive medical materials and appliances. Our SL54TH-A button data loggers help organisations get the best results in the process and ensure complete sterilisation to medical standards.

What Is ETO Sterilisation?

Most metal medical tools and appliances are sterilised using an autoclave, which sanitises surfaces in a steam bath at high temperatures and pressure. However, this method isn’t suitable for many sensitive medical items that may be damaged by high temperatures or moisture, such as packaged equipment used in surgical operations. These individual ‘kit list’ items are stored in clean rooms within plastic tubes and wrapped in external packaging. While the plastic tube inside the packaging will be sterilised, the packaging itself may not be – as it may be exposed to contaminants during storage.

Using an autoclave to sterilise these items may destroy both the packaging and the item, so ETO Sterilisation is used instead. The process exposes the items to a mix of Ethylene Oxide gas (which is highly toxic) and CO2 or water vapour at a low temperature range of 37 to 63°C, effectively killing bacterial and viral pathogens and rendering the items sterile for medical use.

How ETO Sterilisation Works

The process is usually completed in three stages, which is why button dataloggers are helpful, as each stage must maintain precise levels of temperature, pressure, and humidity to be successful.

1) Preconditioning

Establishes optimal temperature and humidity conditions to coax pathogens (yeasts, fungal spores, bacteria etc) out of hibernation into an active state. In their inert state, some infectious pathogens are immune to the effects of ETO gas.

2) Gas Introduction And Sterilisation

The Ethylene Oxide gas mix is released into the chamber at the specified pressure, temperature, and humidity level. The exact levels depend on the level of contamination and the pathogens that need to be addressed.

3) Evacuation/Aeration

The ETO gas is progressively replaced by injecting clean air into the chamber, removing all residual Ethylene Oxide particles on the sterilised items. This is an essential part of the process, as Ethylene Oxide is a carcinogenic compound. Temperature is carefully monitored during this stage to prevent re-contamination.

The full process can take between 36 and 48 hours. Some ETO sterilisation systems add an additional two stages, breaking stage 2 into distinct phases for both gas introduction and sterilisation, and adding an additional air wash stage after evacuation/aeration. A SL54TH-A button data logger will monitor precise temperature & humidity readings at each stage, ensuring optimal conditions are established and maintained.

Find Out More About Our Button Data Logger Range

At Signatrol, we manufacture and supply a wide range of button data loggers to monitor a variety of medical applications, including equipment & process validation, refrigeration and sterilisation equipment. To find out more about our products, or to discuss your requirements with one of our team, please get in touch.