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The EtO Sterilization Dilemma
Patient Safety

The EtO Sterilization Dilemma

Ethylene oxide (EtO) sterilization has been in the news a lot lately, and healthcare has much at stake. According to officials at the U.S. Food and Drug Administration (FDA), approximately 56% of all critical medical devices are sterilized using industrial EtO sterilization. Currently, there are no validated industrial alternatives, so additional closures of EtO processing facilities would have the potential to impair the U.S. healthcare system.

While some state legislators are considering bans on industrial EtO sterilization facilities, healthcare leaders, manufacturers, and FDA have been reviewing options to ensure the availability of sterile medical devices and supplies necessary for patient care.

The EtO sterilization issue, an environmental and patient safety concern, received national attention at FDA’s advisory committee meeting in early November 2019. In light of pending regulatory announcements, the issues, impact, and discourse from the meeting are helpful background for healthcare leaders, supply chain staff, sterile processing managers, and patient safety officers.

What is EtO Sterilization?

EtO sterilization is widely used in healthcare manufacturing for a number of reasons. It can sterilize delicate instruments, devices, and components which would be damaged by other methods. The gas is ideal for sterilizing critical medical devices that cannot withstand moisture or high temperatures. Unlike any other currently available sterilization modality, EtO can penetrate through pallets of cardboard that contain medical devices in their final packaging.

The disadvantage of EtO sterilization is the harmful effects of the gas on people and the environment if EtO is emitted from a sterilization facility. Presenters at the FDA meeting proposed a variety of EtO emission reduction strategies, including:

  • Using additional EtO abatement technologies that convert EtO into inert chemicals
  • Adopting less-conservative sterilization cycles, which aim for a lower overall pathogen reduction
  • Reducing EtO gas concentration per cycle
  • Using smaller, flexible containers that hold medical products and EtO gas cartridges during sterilization

Alternatives to EtO Gas Sterilization

Experts also discussed alternative industrial sterilization methods that could partly or wholly replace EtO gas sterilization. Ionizing radiation, steam, and dry heat sterilization are currently performed at an industrial scale. A representative from Fermilab, a particle physics and accelerator laboratory, explained that gamma radiation, x-ray, and electron beam sterilization modalities rely on the creation of electrons to penetrate devices and supplies during sterilization. A representative from Mevex, an accelerator technology company, said that ionizing radiation disrupts molecular bonds and can modify materials, particularly polymers. Consequently, devices may not perform the same after being irradiated. To reduce the risk of device damage during ionizing radiation sterilization, the Mevex representative suggested that suppliers could use radio-protectants in device materials, change device materials, or modify radiation sterilization processes.

Steam and dry heat sterilization methods also were discussed, including potential modifications to steam sterilization cycles. The presenter stated that lower temperatures would increase steam sterilization cycle times, which are normally one to two hours at temperatures between 121° and 135°C.

Several other sterilization modalities include vaporized hydrogen peroxide, nitrogen dioxide gas, chlorine dioxide gas, and peracetic acid vapor sterilization. However, none of these modalities are currently used in industrial sterilization processes, nor can these methods sterilize packaged devices within cardboard pallets similar to EtO gas.

A Crippled Supply Chain Scenario

A ban of industrial EtO sterilization could have a significant impact on the healthcare supply chain. The GPO firm Premier reported that capacity in industrial EtO sterilization facilities is at 90% or higher. They stated that the capacity to sterilize products will be exceeded if two additional industrial EtO sterilization facilities close in the U.S. Medical device manufacturer Medtronic cautioned that a sudden shift in sterilization procedures may impact healthcare-associate infection rates and that any changes to sterilization methods must be validated to ensure safety for patients and the environment.

Most device manufacturers at the FDA meeting agreed that the uncertain legislative environment is not sufficient incentive to warrant multi-million dollar investments in new industrial EtO sterilization facilities that could be closed if relevant states decide to ban EtO.

Ensuring Access to Sterile Devices and Supplies

Some FDA panel members said that device shortages could be averted if a public health emergency is declared, thereby overriding state EtO bans and re-opening closed industrial EtO sterilization facilities. The panel also discussed EtO abatement technologies. They agreed that these technologies should be used, but also that EtO abatement technologies are not in FDA purview.

As regulators, manufacturers, and legislators ponder the evidence, risks, and remediation steps for EtO sterilization, healthcare organizations should keep in mind that this is a complex issue and one that will not be solved quickly or easily.

Currently, no other validated industrial sterilization process can take the place of EtO gas sterilization. Industry representatives and panel members said it may take up to 10 years before another chemical sterilization modality could be validated and industrialized. Ionizing radiation sterilization methods, although industrialized, are not compatible with as many medical device materials as EtO gas is, and hence, cannot replace EtO gas sterilization for numerous medical devices and supplies.

For these reasons, ECRI Institute continues to oppose a ban of industrial EtO gas sterilization processes because it could result in widespread shortages of critical medical devices and supplies. Such a shortage would endanger patients.

We welcome your input on this topic. Please report any medical device hazards or problems to ECRI Institute’s free Report a Device Problem website and an engineer in our Health Devices group will contact you to investigate.