1. Low TemperatureLow Temperature
SterilizationSterilization
Chapter 16

2. Objectives:Objectives:
As a result of successfully completing this
chapter, students will be able to:
Discuss basic requirements important for any
type of low temperature sterilization system
Explain specific requirements for the three low
temperature sterilization methods: ethylene
oxide, hydrogen peroxide (gas plasma), and
ozone
Review (compare) important parameters of the
three low temperature sterilization methods
commonly used by health care facilities

3. Basic Sterilization RequirementsBasic Sterilization Requirements
Effectiveness
Safety
Monitoring
Quality Assurance
Penetration
Material Compatibility
Adaptability
Approval

4. Ethylene OxideEthylene Oxide
Used commonly in Hospitals since the
1960s
Excellent Penetration Capabilities
Kills microorganisms by alkylation

5. AlkylationAlkylation
The process of destroying
microorganisms by making the cell
unable to metabolize and/or
reproduce

6. Ethylene Oxide ProcessEthylene Oxide Process
ParametersParameters
Time
Temperature
Concentration of
EtO
Relative Humidity

7. TerminologyTerminology
 Residual- The amount of EtO that remains inside of materials
after they have been sterilized
 Aeration- A process in which a device is actively subjected to
moving air. For example, items that have been sterilized with
EtO
 Sterility Assurance Level (SAL)- The probability of a viable
microorganism being present on a product after sterilization
 Permissible Exposure Limits (PELs)- Limits developed by
OSHA to indicate the maximum concentration of a contaminant
to which an employee may be exposed over the duration
assigned to that contaminant
 Time Weighted Average (TWA)- The employee’s average
airborne exposure in any 8-hour work shift of a 40 hour work
week
 Parts Per Million (PPM)- Parts Per Million (PPM) is the term
used to measure the volume of gas in a vapor

8. EtO SystemsEtO Systems
100% EtO
Gas Blends

9. Employee SafetyEmployee Safety
Employees should receive instruction on:
◦ Hazards of EtO
◦ Procedures to reduce employee exposure
◦ Principles of EtO monitoring and interpretation of results
◦ Use of protective equipment
◦ OSHA Standards
◦ MSDS Sheets
◦ EtO Emergency Plans
◦ Processing procedures
◦ Storage and handling of EtO gas containers

10. EtO SafetyEtO Safety
EtO is a Toxic Gas
EtO Sterilizers should be located in a well-
ventilated area with a room air exchange rate of
10 air exchanges per hour
Additional information about EtO safety is
included in Chapter 21, Safety, pages 405 – 408
of the text

11. Personnel MonitoringPersonnel Monitoring
Personal devices worn with
1 foot of the employee’s
breathing zone
◦ Provide delayed results
Area monitors
continuously monitor
airborne EtO
◦ Provide real-time information

12. Education Should also include:Education Should also include:
Specific training
from the
manufacturers of
the gas
containers and
the sterilizer

13. Aeration of EtO SterilizedAeration of EtO Sterilized
ItemsItems
Minimum recommendations for aeration:
◦ 8 hours at 1400
F (600
C)
◦ 12 hours at 1220
F (500
C)
*Some items require significantly longer
aeration. Consult device manufacturer’s
recommendations for specific guidelines

14. Loading the EtO SterilizerLoading the EtO Sterilizer
 Do not overload
 When possible use metal carts
or baskets
 Do not let items come in
contact with chamber walls
 Place peel pouches on edge
 Do not stack items on top of
one another

15. Unloading the EtO SterilizerUnloading the EtO Sterilizer
 If possible aerate before
handling
 When transferring loads to
the aerator, pull, don’t push
the load
 Follow your specific
facility's safety protocols
 Once a load has been
placed in the aerator, new
groups of sterilized items
should not be added

16. EtO Sterilizer PerformanceEtO Sterilizer Performance
MonitorsMonitors
Physical Monitors (Charts, Printout Tapes
and Graphs
Chemical Indicators
Biological Indicators (Bacillus atrophaeus)

17. Hydrogen Peroxide (Gas Plasma)Hydrogen Peroxide (Gas Plasma)
 Popular because of its short cycle
times
 Uses H2O2 vapor and low
temperature gas plasma doe rapid
inactivation of microorganisms
 Is widely compatible with different
materials
 Is not compatible with powders
and strong absorbers like paper
and linen made of cellulose
 There are some restrictions
regarding the sterilization of
lumens (diameter and length).
Consult device manufacturer
recommendations for specific
parameters

18. Staff Safety Education:Staff Safety Education:
Hazards of H2O2
MSDS Sheets
OSHA PEL
Process for changing vapor plates
Storage, handling and disposal of
cassettes

19. MonitoringMonitoring
Physical Monitors (Printout)
Chemical Indicators
Biological Indicators (Geobacillus
stearothermophilus)

20. OzoneOzone
Newest low temperature
process
No purchase of sterilant
needed. The system
generates the O3 needed
Process parameters:
◦ Time
◦ Temperature
◦ O3 Concentration
◦ Relative Humidity

21. Overview of LowOverview of Low
Temperature ProcessesTemperature Processes
A comparison
chart of the low
temperature
sterilization
methods covered
in this unit is
located on page
341 of the text.