Ethylene Oxide (ETO)

Aeration

Loading &Unloading

Because ETO can be absorbed by many materials, aeration is required to remove the residual gases before instruments and packaging can be handeled. When the exposure cycle ends, one or more vaccum pulses remove ETO from the chamber. The aeration phase then takes place as warm air circulates through the chamber removing residuals. It is always recommended to follow the manufacturer's IFU.

Placement of biological indicator

Loading & Unloading cont..

Ethylene Oxide (EtO)

The test pack should be placed flat in a fully loaded sterilizer chamber, in the area least favorable to sterilization. This area is normally in the front, bottom section of the sterilizer, near the drain.

Sources:

Items should be arranged so that they avoid contact with the chamber walls, peel pouches should be placed on the edge inside wire baskets and instruments should never be stacked.

- https://www.steris-ast.com/techtip/parametric-release-ethylene-oxide-sterilized-devices/#:~:text=Traditionally%2C%20ethylene%20oxide%20sterilization%20processes,X%200.25%20inch%20paper%20carrier.

The Environmental Protection Agency requires that ETO sterilizers only be operated with full loads of items that share common aeration times. Emergency situations may require less than full loads and sterile tech's must record this when done. The records must must be kept for 5 years with the most recent 2 years on site.

What type of biological indicators?

Packaging For EtO

Different types of packaging

Ethylene oxide sterilization processes are routinely monitored with biological indicators that are composed of the microorganism Bacillus atrophaeus.

What is Ethylene Oxide?

Tyvek pouches and rolls

Tyvek, a synthetic material made of high-density polyethylene fibers, is breathable and allows for effective ethylene oxide sterilization. Pouches or rolls made of Tyvek are often used to package items before subjecting them to ethylene oxide sterilization.

Paper-plastic pouches

Ethylene oxide (ETO) has been widely used as a low-temperature sterilant since the 1950s. It is a colorless, flammable gas that can kill a wide range of microorganisms, such as bacteria, fungi, and viruses. It has been the most commonly used process for sterilizing temperature- and moisture sensitive medical devices and supplies in healthcare institutions in the U.S. Two types of ETO sterilizers are available, mixed gas and 100% ETO.

Polyethylene bags

These pouches often have a combination of paper and plastic layers. The plastic layer acts as a barrier to moisture, while the paper layer provides breathability for ethylene oxide penetration.

Polyethylene bags can be suitable for ethylene oxide sterilization. These bags are gas-permeable, allowing the ethylene oxide to penetrate and sterilize the packaged items.

Sterilization Wraps

Dual-barrier pouches

Form-fill-seal pouches

Nonwoven fabrics or other materials designed to allow ethylene oxide penetration are used as sterilization wraps. These wraps are often used to package individual items or sets of instruments.

These pouches typically have two layers, with the inner layer in direct contact with the medical device and the outer layer acting as a barrier to microbial ingress. The materials used in these pouches are chosen to be compatible with ethylene oxide sterilization.

Similar to those used in hydrogen peroxide sterilization, form-fill-seal pouches are created through a continuous manufacturing process. These pouches are filled with the product and then sealed, and the materials used are compatible with ethylene oxide sterilization.