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3M
™
Steri‑Vac
™
Sterilizer / Aerator GSXSeries – Operator’sManual
13.3. Overview of GSX Series Ethylene Oxide (EO) SterilizationCycle
13.3.1. Cycle Stages andDescriptions
3M™Steri‑Vac™ Sterilizer/Aerator GSX Series ethylene oxide (EO) sterilization cycles consist of ten stages. After the sterilization cycle is complete, an aeration cycle is required to remove any
residual EO from the medical devices per the manufacturers’ instructions for use(IFUs).
While a sterilization cycle is running, icons on the bottom of the display screen indicate the current stage of the cycle (both with a white box around them and in the stage indicator). Each icon,
and the corresponding sterilization cycle stage, is describedbelow.
Stage 1:Preheat
The temperature of the sterilizer chamber is controlled to attain the pre‑set
operatingtemperature.
Stage 2: AirRemoval
A vacuum is created to remove air from the chamber and load. The vacuum rate is dependent
upon the nature of the sterilization load, environmental conditions and preprogrammed
vacuumrate.
Stage 3: ChamberTest
The Chamber Test measures the integrity of the sealed system and chamber. The test is carried
out prior to the start of both the EO Injection stage and Conditioning stage at a pre‑set vacuum
level. Once the vacuum level is obtained, the pressure rise in the chamber is monitored for the
set point duration, after an appropriate equilibration time that allows for pressure stabilization.
During this period, the final chamber pressure measurement minus the initial chamber
pressure measurement must be less than 18mBar (1.8kPa).
Stage 4:Conditioning
The Conditioning stage involves treatment of the product load within the sterilization cycle, prior
to EO admission, in order to attain a predetermined temperature and relative humidity. This part
of the sterilization cycle is carried out completely under vacuum in the GSX Seriessterilizer.
Stage 5: EOInjection
When the 3M™Steri‑Gas™ EO Gas Cartridge is punctured, EO is vaporized and pulled into
the chamber by the pre‑injection chamber vacuumlevel.
Stage 6: EOExposure
EO Exposure is the pre‑set time period between the end of EO Injection and the beginning of
EO Removal when EO is sterilizing theload.
Stage 7: EORemoval
During this stage, EO is removed from the sterilizer chamber but not necessarily removed from
the sterilizationload.
Stage 8:Flushing
During the Flushing stage of the sterilization cycle, the EO is removed from the load and the
open chamber space of the sterilizationchamber.
Stage 9:Aeration
During Aeration, EO desorbs from the product load and devices until predetermined levels of
EO are reached. Aeration in the GSX Series sterilizer begins automatically after the sterilization
cycle is complete. Aeration duration is based on the selection made by the Operator, either a
specific time or continuousaeration.
[No Icon] Stage 10: Air AdmissionStage
Filtered air is admitted into the chamber to allow the chamber pressure to equilibrate with
ambient pressure. An “Opening door…” message will appear on the display screen during the
Air Admissionstage.