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Thinking of Buying...Non-steam Sterilizers
Know your instruments, then pick based on your facility's needs.
Theresa Matthews
Publish Date: November 17, 2007   |  Tags:   Infection Prevention

Before you replace your sterilizer with the latest technology, you first have to do your homework. Ask yourself: What instruments will I be placing in the autoclaves? What sterilization types are they compatible with? How quickly do I need to sterilize these instruments and turn them around? What are the utility requirements? How much space do I have? Will the sterilizer have any down time? With so many questions to answer, you'll want to consult the clinical staff, sterile processing staff and physicians as much as possible before making your decision.

The steam autoclave is still the most common sterilizer. It's the most economical choice and it can reprocess most basic surgical instruments. But what about the instruments that are too sensitive for steam? Low-temperature autoclaves (non-steam) are as varied as the items they can sterilize and each has its niche in the surgical environment. Here's a review.

Ethylene oxide used to be the primary choice in low-temperature sterilization, but it has become somewhat obsolete since the arrival of newer technologies. With the advent of other low-temperature sterilizers, many facilities have chosen to replace their EtO units because of the gas's toxicity and long cycle time. The average dwell time for EtO is two hours with a 12-hour aeration cycle. This makes EtO inadequate for most surgical centers. You can purchase enough instruments so that turnover time isn't as much of an issue, yet that alone can be cost-prohibitive for many facilities.

There is still a place for EtO sterilizers. Many instruments are incompatible with newer sterilizers due to their lumen size and not every item has been validated by the OME for anything besides EtO.

If you do plan to purchase an EtO autoclave, you should understand the regulations surrounding the use of EtO. Some states require that staff have a pesticide license to handle the harmful gas; others require abatement systems on the exhaust, which are very costly. From a safety standpoint, the new cartridge delivery systems pose no threat to your staff. However, you still have to monitor the air for EtO residuals and keep records for 30 years after your staff leaves the facility. AAMI regulations require a biological indicator (BI) in each load of EtO. Two types are on the market: the conventional, which has a 48-hour read, and the new rapid read, which provides results in four hours. Instruments reprocessed in EtO don't have to be quarantined until the results are known, but as with all BI's, you must have a recall process in place.

Peracetic acid
Steris's System 1 uses peracetic acid as its sterilant. This system is used for items that require low-temperature sterilization and must be fully immersible. The cycle time of this sterilizer varies from 28 minutes to about 35 minutes, depending on the temperature of the hot water going into the machine. If your water isn't hot enough (at least 140°F), you might have to place a heat booster on your hot water intake. This autoclave also requires a series of water filters to achieve the sterile water required to process the instruments. The System 1 has a general purpose tray for processing rigid scopes and cameras. This tray has a lid so you can transport the items from the sterilizer to the OR. This is a "just in time" system, meaning the items can't stay in the processor until they're used. The flexible scope tray must have the correct adapters for the scopes you're processing. A diagnostic cycle must be run daily to check the functioning of the System 1. AAMI requires that a BI be performed daily. You can get the results in 48 hours or seven days, depending on the product you use.

Gas plasma
Advanced Sterilizations Products' Sterrad sterilizers use hydrogen peroxide and radiofrequency technology to create the vapor for their gas plasma sterilizers. The only utility required is electricity. They have various models to choose from: the 200, 100S and the NX. The chamber size in the 200 is 5.3 cubic feet of usable space with a 75-minute cycle. The 100S has 3.5 cubic feet of usable space with a 55-minute cycle. The NX has 1.1 cubic feet of usable space and has two different cycles; the standard takes 28 minutes and the advanced takes 38 minutes.

The advanced cycle is a breakthrough for single channel flexible scope sterilization. It is the first non-EtO sterilizer to offer a wrapped product for flexible scopes. The advantage of this product is the quick turnaround time with a shelf life. The items that are processed in these sterilizers must be very dry, otherwise the cycle can abort; excess moisture will interfere with the autoclave. The BI's have to be done daily. The results are available within 48 hours.

The newest members of the low-temperature sterilizer family are the TSO3 Ozone sterilizers. These sterilizers subject water and oxygen to an electrical charge to create the ozone. The chamber is 4.3 cubic feet with a cycle of four and a half hours. This longer cycle time may require you to purchase additional instrument inventory to meet the needs of your surgical center. The utility requirements for this sterilizer are USP grade oxygen, water and electricity. These autoclaves also give the users a wrapped product with shelf life. The Ozone, like the Sterrad, also has limitations regarding lumens. The BI's are done daily; the results are available in 48 hours.

Take-home assignment
These sterilizers have pros and cons regarding their processes and instrument compatibility. Review the manufacturer's information for each instrument you sterilize. The advent of these new technologies has assisted us in giving quality care to patients, but they won't do you any good if your instruments aren't compatible. Call or visit sites that use the equipment that you're considering and ask questions about reliability, cost of operation, training and service.

Steri-Vac Series
(888) 364-3577
Price: $35,000 to $60,000 for the 5XL; $50,000 to $75,000 for the 8XL
FYI: This system, available in 5XL (4.8 cubic feet) or 8XL (7.9 cubic feet) models, uses 100 percent EtO, unit-dose cartridges for efficiency and cost-effectiveness, says 3M. The lack of additive diluent gases lets the sterilizer operate at negative pressure throughout the cycle to prevent leakage. A video screen displays the cycle status and the machine automatically goes into aeration mode after the cycle is complete. The 8XL model has a sensing system that monitors and controls relative humidity during the preconditioning phase to optimize moisture level. You can choose between single- or double-door models.

Advanced Sterilization Products
Price: Not disclosed
FYI: This gas plasma sterilizer can process a wide range of instruments and handle a high caseload. It can process most surgical instruments in a 28-minute cycle or single-channel flexible endoscopes and semi-rigid ureteroscopes in 38 minutes. The company says the STERRAD NX is gentler on instruments than steam or peracetic acid. The advantages of this product are the quick turnaround time and that the instruments don't lose sterility right after they're done processing, says ASP.

Anderson Products
EOGas Series
(800) 523-1276
Price: $18,000 to $40,000, six to 33 cubic feet of capacity
FYI: The EOGas Series uses one tenth of the EtO gas of other sterilizers (11 grams per cycle), says the company. This minimalist approach reduces residuals and operator exposure. The microdose delivery system uses a small ampule of EtO contained within a bag so the user doesn't have to flood a large chamber with gas to sterilize smaller, delicate instruments. A multi-load system allows loads to be added and removed throughout the day.

System 1 Sterile Processing System
(800) 548-4873
Price: $21,000 for the P6000 model
FYI: The System 1 Sterile Processing System uses peracetic acid and has a cycle time of half an hour. There is no need to wrap or dry the instruments before processing; however, the instruments should be removed as close to the time of usage as possible. The point-of-use sterilization feature lets the operator perform the entire reprocessing cycle within the OR, as opposed to sending the instruments out to an EtO sterilizer, says the company. The System 1 boasts a low cost of reprocessing on a per-cycle basis and a low capital cost, says Steris.

Reliance EPS Endoscope Processing System
(800) 548-4873
Price: $40,969 to $43,969
FYI: Though it's not a sterilizer, this high-level disinfection system reprocesses scopes too fragile for sterilization. Designed specifically for use in the GI Department, the Reliance EPS features "boot technology" that seals around the control handle of the endoscope to perform a high-level disinfect of the scope's surface and lumen without the use of connectors, says Steris. Instead of using aldahyde-based chemistry that can accumulate microorganisms after several uses, paracetic acid is formed inside the system and only used once per cycle. The machine has an integrated decontamination system and leak tester.

125L Ozone Sterilizer
(418) 651-0003
Price: $165,000
FYI: The 125L has a capacity of 3.8 cubic feet and uses ozone as a sterilant. With the push of a button, it humidifies 75ml of water into vapor, creating a humid environment in the sterilization chamber. It then creates ozone and frees up oxygen atoms that attach themselves to organic matter on the instruments to sterilize them. The system then runs the ozone through a catalytic converter and releases it into the atmosphere as oxygen and water vapor. There is no chance of operator exposure. The process takes about four and a half hours, but costs less than a dollar per cycle, says the company. If your center sterilizes instruments a day in advance, you might not need to pay for a quicker cycle. Ozone is not yet certified by the FDA for use on flexible scopes.