Making Decisions About Home Care

Ethylene Oxide Device Sterilization

by Mae Ferguson

Ethylene Oxide Device Sterilization

Removing micro-organisms and biological agents (prions) from the medical device using ethylene oxide(C2H4O) is called ethyl oxidation device sterilization. The ethylene oxide gas can sterilize medical devices sensitive to water and heat. Ethylene oxide is also used to sterilize rubber and plastic materials, including bags, masks, and fiber-optic instruments.

Critical items:

Items like surgical equipment, biopsy forceps, and implanted medical equipment touch the body fluids directly, resulting in disease transmission, so they need to get sterilized. These items are also called critical items. Low-temperature gas sterilization is required for critical items sensitive to heat and water and cannot be sanitized by steam, which has a very high temperature.

Ethylene oxide is used to sterilize critical items.

Sterility assurance level:

The use of critical items in the medical industry can cause the transmission of pathogens and diseases. However, this form of transmission is exceptionally rare because of sanitation measures. 

The definition of sterility assurance level of the product can be defined as the probability of finding a single alive micro-organism on a sterilized product. The probability is normally represented by 10n

How ethylene oxide kills micro-organisms?

Ethylene dioxide is a colorless and odorless gas that kills micro-organisms by rupturing their cell membranes. When ethylene oxide interacts with living material, alkylation happens. The structure of amino acids alters when a hydrogen atom is replaced by a hydroxyethyl radical in this process.

These proteins rupture the cell membrane and create a conduit between the interior and exterior of the cell. The alkylation process can occur with RNA, DNA, and protein that cause metabolization and replication processes of cells. 

ETO sterilization cycle:

The Ethylene oxide sterilizes the medical devices in five stages and repeats the cycle.

In the first step, preconditioning and humidification are carried out.

The second step involves the gas introduction in the chamber.

In the third step, the exposure occurs, followed by the fourth evacuation step. Then finally, air washes happen for several hours.

The same chamber is used to sterilize and aeration as a continuous operation in modern ethylene oxidation sterilizers. 


The precautionary measure should be taken while using ethylene oxide gas because its exposure can cause pain in the eyes, sore throat, difficulty breathing, headache, vomiting, and coughing. Invitro studies show that ethylene oxide is also a carcinogenic chemical it is also related to sudden abortion, genetic cells damage, nerve damage, and other diseases.

For more information on EO device sterilization, contact a service in your area.