Sterilization of
Instruments
Microbiology and Infection Control
Pearson, 3rd edition
Microorganisms that cause disease
are known as: (hint: suffix for
“disease” is –pathy)
a. Carriers
b. Pathogens
c. Vectors
d. Saphrophytes
Pearson, 3rd edition
Bacteria that live only in the
presence of oxygen are called:
a. Parasites
b. Anaerobes
c. Pathogens
d. Aerobes
Microbiology and Infection Control
Lange, 6th edition
Staphylococcus aureus would most
likely be transmitted by
a. Urine
b. Feces
c. Nose and mouth
d. Sex organs
Lange, 6th edition
The body’s first line of defense
against the invasion of pathogens
is:
a. The immune response
b. Skin and mucous membrane
linings
c. Cellular and chemical response
d. Phagocytosis
Bioburden
https://www.istockphoto.com/photo/bloody-surgeontools-post-operation-gm466280124-58886552
Pearson, 3rd edition
Bioburden refers to:
a. An agent that kills
microorganisms on inanimate
objects
b. The process of destroying all
microorganisms, including
spores
c. Inhibition of bacterial growth
d. The degree of microbial
contamination
Glutaraldehyde (Cidex)
• High-level disinfectant compounds
• Contaminated device will be completely
immersed in liquid
• Use syringe and glutaraldehyde to
remove air and flush lumens
• Used most on flexible/rigid endoscopes
• “Shelf life”
•
•
14- to 28 days
Test prior to each use during 14- to 28day period
• Item must be cleaned and dry before
emersion
• After cleaning, rinse thoroughly – sterile
water
• High-level disinfection: 20 minutes
• Sterilization: 10 hours
• Use care in handling (gloves, protective
eyewear, mask, well-ventilated room)
CST Exam
Review
Questions
Lange, 6th edition
Lange, 6th edition
What is the shelf life of Cidex?
Which of the following is essential
when using activated
glutaraldehyde for sterilization?
a.
Between 14 and 28 days
b.
7 days
c.
1 month
d.
indefinite
a.
Items must be rinsed
thoroughly in sterile water
before use
b.
The solution must be heated
in order to be effective
c.
The items must be thoroughly
moistened before placement
in solution
d.
The item must be air dried
before use
CST Exam
Review
Questions
Lange, 6th edition
The commercial name for
glutaraldehyde is
a. Peracetic acid
b. Phenol
c. Quats
d. Cidex
Lange, 6th edition
In which procedure would the
use of high-level disinfectant
be acceptable instrument
preparation?
a. Suction lipectomy
b. Tracheotomy
c. Cystoscopy
d. Mediastinoscopy
Note: cystoscopy is a “clean”
case that enters a mucous
membrane; the other
procedures are sterile cases
and instruments must be
sterilized.
• General principles of packaging
• Maximum size of a muslin-wrapped linen pack is
12”x12”x20” (height x width x length)
• Linens packed loosely, packs cannot weigh more than
12 pounds
• Double-ply wraps are essential for proper bacterial
barrier
• All packages must be inspected for holes, tears,
perforations and seal integrity before opening
• Use chemical indicator tape; label contents of package
• Instrument sets should not exceed 25 pounds
• If too densely packed, sterilant might not
penetrate
• Steam Sterilization:
• Lumens: residual amount of distilled water left inside
to displace air
• Heavy instruments on the bottom; lighter on the top
• Basins placed in autoclave on their side, concave side
down
To be sterilized effectively, a linen pack
must not weigh more than
a.
12 pounds
b.
14 pounds
c.
16 pounds
d.
18 pounds
Chemical Indicators
• Chemical monitors for Steam Sterilization
• Used externally and internally
• Verify item has been exposed to sterilizing conditions
• Do NOT verify the sterility of an item
• Aids in detecting machine malfunction (air pockets)
• Incorrect assembly or wrapping
• Incorrect loading of sterilizer
• Class 1-6, based on specific information that device indicates
• Paper impregnated with a dye that changes color in the presence of
temperature and sterilant
• Autoclave tape
• Before exposure: cream-colored with diagonal lines
• After exposure: lines turn black
Mechanical Indicators
Biological indicators (BI)
Lange, 6th edition/Pearson, 3rd edition
Contain specific spore-forming microorganism
Positive assurance that sterilization conditions
have been achieved can only be obtained
through
• Only test that guarantees items are sterile
• Steam Sterilization: Geobacillus stearothermophilus or
Bacillus atrophaeus
• Placed in most difficult area for sterilant to reach;
bottom front, over chamber drain
a.
Biologic control test
b.
Heat-sensitive test
c.
Color change monitor
d.
Mechanical indicator
The most reliable means of monitoring the
effectiveness of the sterilizer that ensures sterilization
parameters have been met is:
a. Biological
b. Mechanical
c. Chemical
d. None, monitoring is not required
Ethylene Oxide gas (ETO)
•
Gas sterilization used to process materials that cannot tolerate steam sterilization
• Plastic, rubber, wood
• Effective against all microorganisms, including spores
• Expensive; may take up to 16 hours
• Water combines with EO gas to form a harmful acid, so all lumens should be blown
out with air
•
Dangerous
• Flammable and very toxic
• Health care personnel concerns:
• Skin irritation, respiratory difficulty, headaches, nausea
• Linked to cancer, reproductive difficulties and chromosomal alteration
• Produces chlorofluorocarbons (CFCs) which are harmful to environment
• Exhausted to outside health care facility
• Items must be aerated after sterilization, 8-12 hours if at room temperature
•
Aerator is a separate unit that enhances the dissipation rate of absorbed gases, resulting in
faster removal.
CST Exam Review Questions
Pearson, 3rd edition
Aeration is essential following
sterilization by:
a. Ionizing radiation
b. Hydrogen peroxide plasma
c. Activated glutaraldehyde
d. Ethylene oxide gas
Lange, 6th edition
Why would gas sterilization be
chosen over steam sterilization?
a. It is less expensive
b. It is less damaging to items
c. It is faster
d. It is more effective
CST Exam
Review
questions
Lange, 6th edition
Lange, 6th edition
The chemical agent used in gas
sterilization is
The lumen of a tubing
undergoing ethylene oxide
(EO) sterilization is
a.
Ethylene glycol
b.
Ethacrynate sodium
a.
Well lubricated
c.
Ethyl chloride
b.
Dried thoroughly
d.
Ethylene oxide
c.
Prepared with a
residual of distilled
water
d.
Prepared with a NaCl
flush
CST Exam
Review
questions
Lange, 6th edition
Lange, 6th edition
What is the role of moisture in EO
sterilization?
What is the function of an aerator
in EO sterilization?
a.
a.
It is used to aerate items
before sterilization
b.
The sterilizer will deteriorate
from gas over a period of time
if no moisture is added
It is a separate unit used to
decrease the aeration time
c.
Dried spores are resistant to
the gas, so they must be
hydrated
It is the last cycle of the EO
sterilizer, which helps
exhaust the gas and add air
d.
It adds air to the cycle,
which is essential for
obtaining item sterility
b.
c.
d.
The items will dry out during
the process if no humidity is
added
Moisture is not an essential
element in gas sterilization
CST Exam
Review
Questions
Lange, 6th edition
Pearson, 3rd edition
What method of sterilization is
used on objects that cannot
tolerate heat, moisture, and
the presence of steam
sterilization?
The safest, most practical
means for sterilizing heatand moisture-stable items is:
a.
Saturated steam under
pressure
a.
Gravity displacement
b.
Ethylene oxide gas
b.
ETO
c.
c.
Hydrogen peroxide
Activated
glutaraldehyde
d.
Cidex
d.
Boiling water
Prevacuum Steam Sterilizer
aka: Dynamic-Air-Removal
• Vacuum pump removes air
• Utilizes Bowie-Dick Test during first run of the day
• Place package horizontally, between 22-24 absorbent
towels in a stack that is 9x12x11
• Commercially available as Daily Air Removal Test
(DART)
• Does not test for sterilization; tests only for vacuum
system
• 270° - 27 psi
Steam Sterilization
Important facts from p. 158, Table 7-16 and 7-17:
• Gravity Displacement Steam Sterilization
• Instrument set, wrapped
• Instrument set, unwrapped – no lumens (suction tips)
• Instrument set, unwrapped with lumens
• Dynamic-Air-Removal Steam Sterilization (Prevacuum)
• Instrument set, wrapped
• Instrument set, unwrapped – no lumens
• Instrument set, unwrapped, some lumens
You cannot “flash” a wrapped instrument
270° - 15-30 minutes
270° - 3 minutes (Flash)
270° - 10 minutes (flash)
270° - 20-30 minutes
270° - 3 minutes (flash)
270° - 4 minutes (flash)
Sterilization of Basin
Sets
• Pearson – 3rd Edition
• Which of the following statements
regarding the sterilization of basin sets is
true?
• Basins must be separated by a porous
material if they are nested.
• Sponges and linen may be packaged
inside the basin to be sterilized
• Basins are placed flat in the autoclave
• Basins must always be placed on the
top shelf of the autoclave in a
combined load.
Steam
Sterilization
Lange, 6th Edition
Pearson, 3rd edition
The amount of pressure
necessary in a steam sterilizer
set at 250° is
If the temperature on the
steam sterilizer reads 270°F,
what should the pressure
reading be?
a.
15-17 pounds
b.
20-22 pounds
a.
15-17 psi
c.
22-25 pounds
b.
20-25 psi
d.
25-27 pounds
c.
27 psi
d.
30 to 36 psi
CST Exam
Review
questions
Pearson, 3rd edition
Pearson, 3rd edition
In the middle of the surgical
procedure, a critical stainless
steel instrument is
contaminated and there is no
sterile replacement. Which
time setting would be selected
for the flash autoclave?
A Bowie-Dick test must be
run daily in which of the
following types of sterilizers?
a.
a.
Ethylene oxide gas
b.
Hydrogen peroxide
plasma
3 minutes
c.
Peracetic acid
b.
10 minutes
d.
Prevacuum
c.
15 minutes
d.
30 minutes
CST Exam
Review
Questions
Lange, 6th edition
Lange, 6th edition
All of the following statements
regarding instrument sets are
true EXCEPT
All of the following statements
regarding steam sterilization are
true EXCEPT
a.
Instruments must be
placed in perforated trays
b.
Heavy instruments are
placed on the bottom
c.
All instruments must be
closed
d.
All detachable parts must
be disassembled
a.
Flat packages are placed on
the shelf on edge
b.
Small packages, placed one
on top of the other, are
crisscrossed
c.
Basins are placed on their
sides
d.
Solutions may be
autoclaved along with
other items as long as they
are on a shelf alone
Steris – Peracetic Acid
• Alternative to steam under
pressure and ETO
• Appropriate for items that are heat
sensitive, but moisture stable
• Steris System 1E – Peracetic Acid
• 23-30 minute cycle
• Liquid chemical sterilant often used
for sterilizing endoscopes
• Item cannot be stored; for immediate
use, only
• Biological indicator: geobacillus
stearothermophilus
Sterrad: Hydrogen
Peroxide Gas Plasma
(p. 165)
• Sterrad:
• Uses gas at low temperature to sterilize
heat and/or moisture sensitive items
• Safer than ETO and is replacing it in many
health care facilities
• Biological indicator: Bacillus atrophaeus
• Not good for cleaning items with lumens
• Peel-packs made of Tyvek
• Leave adequate space between items for
penetration of sterilant
• Cycles from 28-38 minutes
• Does not require aeration, drying or
cooling
CST Exam
Review
questions
Lange, 6th edition
Lange, 6th edition
What chemical system uses
peracetic acid as the sterilant?
A 30-minute single-use
sterilization system useful for
endoscopes is
a.
Ozone gas sterilization
b.
Steris
a.
Steris
c.
Sterrad
b.
ETO
d.
Vapor phase sterilizer
c.
Steam under pressure
d.
Cold sterilization