66
3M
™
Steri‑Vac
™
Sterilizer / Aerator GSX Series
– Operator’s Manual
13.3. Overview of GSX Series Ethylene Oxide (EO) Sterilization Cycle
1331 Cycle Stages and Descriptions
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 described below
Stage 1: Preheat
The temperature of the sterilizer chamber is controlled to attain the pre‑set
operating temperature
Stage 2: Air Removal
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
vacuum rate
Stage 3: Chamber Test
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 18 mBar (18 kPa)
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 Series sterilizer
Stage 5: EO Injection
When the 3M™ Steri‑Gas™ EO Gas Cartridge is punctured, EO is vaporized and pulled into
the chamber by the pre‑injection chamber vacuum level
Stage 6: EO Exposure
EO Exposure is the pre‑set time period between the end of EO Injection and the beginning of
EO Removal when EO is sterilizing the load
Stage 7: EO Removal
During this stage, EO is removed from the sterilizer chamber but not necessarily removed from
the sterilization load
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 sterilization chamber
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 continuous aeration
[No Icon] Stage 10: Air Admission Stage
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 Admission stage
