While steam is the most commonly used and most economical method for reprocessing instruments and equipment, some items can't tolerate the high temperature, moisture and pressure of steam sterilization. Plastic components can melt, lenses can fog and the quality of many devices that aren't made of stainless steel can be compromised. For these instruments, a low-temperature reprocessing alternative is necessary. You've got 4 options:

• ethylene oxide
• hydrogen peroxide gas plasma
• ozone
• liquid chemical sterilization

Choosing the method (or methods) that satisfies your facility's sterilization needs depends largely on your instruments' specifications and your surgical schedule's demands. Here's a review.

Ethylene oxide
Ethylene oxide (EtO) is the oldest of the currently available non-steam sterilization options. Industrial researchers began commercial production of the gas compound early in the 20th century, and it was initially put to use as a chemical weapon in the world wars and a pesticide and fungicide for agricultural use before its high effectiveness in killing bacteria, spores and other organic matter found an application in health care.

This toxicity is in fact the chief concern for facilities using ethylene oxide for sterilization. While the gas is delivered safely during the process through cartridges, high-powered ventilation is required to remove it, and some states require specialized exhaust abatement systems. You'll need to invest in training for your reprocessing techs on the handling and use of EtO — some states also require that the equipment's operators obtain pesticide licenses — and establish safety protocols for monitoring the air and responding in the event of a leak.

Another major concern in using EtO is its lengthy turnaround time. On average, it takes about 2 hours for the gas to permeate the spaces in wrapped packages and the lumens of cannulated instruments, but it can take another 12 hours or more for the sterilizer to sufficiently evacuate the gas and aerate the reprocessed items. Unless you have an unlimited supply of instrument sets on your shelves, relying solely on EtO may not be an optimal choice for efficiency-minded facilities.

EtO was once the leading low-temperature sterilization option. Even though it has in the past decade been overtaken by faster methods that use less expensive sterilants, and even as many facilities have been phasing out their EtO equipment, there's still a use for it in central sterile. For cannulated instruments with longer lumens, such as flexible endoscopes, the gas has been found to penetrate the interior spaces more effectively than hydrogen peroxide gas plasma and ozone methods do. As a result, some manufacturers specify the use of EtO in reprocessing their devices. And facilities that have renovated EtO out of their sterile processing departments have opened the door for third-party reprocessors who offer outsourced EtO sterilization.

Hydrogen peroxide gas plasma
Over the past 5 or 10 years, hydrogen peroxide gas plasma sterilizers have made great gains in market share. This technology offers non-steam, low-temperature reprocessing, even for wrapped packages, in about 45 to 70 minutes, a turnaround time rivaling that of steam autoclaves.

As with EtO, the potentially hazardous sterilant is delivered by way of a self-contained, disposable cartridge, and like EtO, the only utility necessary for operation is electricity. Vaporized hydrogen peroxide circulating in the chamber is ionized by radiofrequency energy to create plasma, a chemical change that facilitates microbial kill and effective sterilization. No special ventilation is needed after the cycle is completed and no toxic residues remain on the reprocessed items

While gas plasma sterilizers can handle a wide range of instruments, they may not be as effective on long-lumened devices as EtO is, as mentioned above. As even the slightest amount of moisture can interfere with the sterilization cycle, instruments must be carefully and thoroughly dried before they're loaded into the chamber. Also, only compatible packaging can be used in gas plasma sterilizers. A polyethylene wrap such as Tyvek is acceptable, but polypropylene, linen, paper, paper-plastic composite and peel-pack wraps are not.

Ozone
Introduced on the American market within the last 10 years, ozone sterilization has been promoted as the most environmentally friendly reprocessing option, but it has yet to see widespread adoption in the nation's sterile processing departments.

The technology doesn't require much in the way of utilities, just an electrical outlet, a source of medical-grade oxygen and distilled water. An electrical charge separates the oxygen atoms to create ozone, which oxidizes and neutralizes microbial cells and sterilizes the instruments, wrapped or in trays, in the chamber.

Since oxygen and water are the only byproducts of this process, no specialized aeration or ventilation is required, though you'll need access to a drain. Like gas plasma, ozone cannot be relied upon to sterilize instruments with long lumens. Addition-ally, its 4 ?-hour cycle — longer than steam or hydrogen peroxide gas plasma, though not nearly as long as EtO — requires either diligent planning ahead or a sufficient inventory of the most-needed instruments for efficient reprocessing.

Liquid chemical sterilants
Unlike the EtO, hydrogen peroxide gas plasma and ozone options, which can deliver dry and wrapped reprocessed items for later use, liquid chemical sterilization is a wet method. Items are immersed and soaked in a solution, after which they are thoroughly rinsed. Because they cannot be wrapped, they must be used immediately.

There has been some recent controversy between regulators and manufacturers over whether an instrument that is wet can be considered sterile — as opposed to simply high-level disinfected — and if so, how long it will remain sterile. In this way, liquid chemical sterilization somewhat resembles flash sterilization in its dependence on aseptic handling and transportation for immediate or just-in-time use.

A variety of products are available for liquid chemical reprocessing, including glutaraldehyde, activated glutaraldehyde, orthophthaldehyde and peracetic acid. They're ideal for use with long lumens and in fact are often used in automated scope reprocessors. The effective shelf life, concentration and soak time for each vary from product to product, though most offer sterilization after a soak of 30 to 45 minutes.

Each product requires that instruments be thoroughly cleaned prior to immersion, that all surfaces make contact with the chemical solution and that they're carefully rinsed before they're used. As respiratory and skin irritants, their potential hazards to your employees also demand such safety precautions as ventilation, proper personal protective equipment use, air monitoring and spill emergency training.

Choosing a method
The diversity of materials used in the latest surgical technology means that a facility can't rely on steam alone to meet its sterilization needs. The differences in abilities and limitations of low-temperature methods likewise mean you might need to invest in more than 1 option for your sterile processing department to cover all bases and back up your backup plan.

Choosing a method or methods to use should be guided by consultations with your reprocessing technicians and your clinical staff in tandem, as their tasks and needs will intersect on this decision. While you'll want to install a system that reprocessors can easily learn and safely use, your surgeons, nurses and scrub techs have a vested interest in one that can handle the items they operate with and can deliver sterilized tools in time with their surgical schedule.

As a result, keep in mind each method's turnaround time as well as the number of cases per day, the amount of instruments they generate and your available inventory of instruments, since sterilizing a full load is more cost-effective than running a cycle at partial capacity. Remember also that the method chosen may influence the instruments your facility is able to purchase (and subsequently reprocess) in the future, depending on the recommendations of the manufacturer, FDA, AAMI, AORN, IAHCSMM and other organizations with reprocessing expertise.

Every sterilization method has a cost. While the low-temperature methods are fairly simple in terms of utilities — some require little more than an electrical outlet to operate — you'll also have to budget for the continuing cost of their sterilizing agents and possibly for protection against their potential environmental effects through ventilation, personal protective equipment, training and emergency planning. Finally, the cost of a service contract can make a big difference in keeping your reprocessing department running through the little fixes of preventive maintenance and the big fixes of repair.

Advanced Sterilization Products
Sterrad NX System
(800) 595-0200
www.aspjj.com
List price: not disclosed
FYI: This hydrogen peroxide gas plasma sterilizer offers speed — a 28-minute cycle for most general surgical instruments and a 38-minute cycle for single-channel flexible endoscopes — and safety in a compact size, says the company. Delivers dry, sterile, packaged instruments for immediate or later use, and the cycle produces only water vapor and oxygen. No special heat boosters, plumbing, aeration or ventilation is required, and the cart-mountable unit can easily be moved where it is needed. Includes software that allows networking with practice management systems and diagnostic abilities.

Andersen Products
EOGas Series 3 Plus
(800) 523-1276
www.anpro.com
Price range: $19,760 to $37,440
FYI: This ethylene oxide system employs a unique bag and cartridge configuration to match the amount of EtO used to the load size for effective sterilization without using excess gas, satisfying the EPA's full-chamber regulations for EtO sterilizers, says the company. The standard cycle operates at 50 ?C and requires 16 hours for sterilization and aeration in the same chamber, meeting EPA requirements. The low-vacuum, low-temperature, low-humidity process lets you reprocess delicate instruments. Available with cabinet sizes of 6, 10 and 33 cubic feet. Easy to install, requiring only an electrical supply and a simple dedicated vent. Emissions abatement equipment is available for all sterilizers.

Steris Corporation System 1E Liquid Chemical Sterilant Processing System
(800) 548-4873
www.system1e.com
List price: $31,500
FYI: Maintaining a tight OR or GI schedule requires quick access to reusable devices. Steris says its System 1E provides the solution. Running a 23-minute cycle, it offers fast reprocessing of cleaned, reusable, immersible, heat-sensitive critical and semi-critical devices. Two pre-filters, UV irradiation and a MaxPure filter work together with S40 Sterilant Concentrate for a validated process. The use-dilution is gentler on delicate instruments, including multi-channel flexible endoscopes. It has neutral pH and rinses safely down the drain. When used in accordance with its indications for use, the System 1E helps facilities reprocess surgical or GI instruments efficiently and with confidence.