ASEPTIC TECHNIQUE AND
STERILIZATION METHODS
CTVT PGS 1158-1168
Objectives:
Understand aseptic technique
Learn how to properly sterilize
instruments and equipment
 Asepsis- condition of sterility where no
living organisms are present
 Aseptic technique-
all steps taken to
prevent contamination of surgical site by
infectious agents
 Goal: to “maintain asepsis“ and watch
for “breaks” in aseptic technique
Where do contaminants come from?
 Exogenous sources:
o
You, patient’s fur/skin, instruments, air
 Endogenous:
o
Inside the patient  reach the incision
through blood stream
•
Example – Periodontal disease
Ways to Maintain Aseptic Technique
Disinfection - destruction of pathogens on
inanimate objects (Kennel Care)
o Doesn’t effect bacteria spores
 Sanitization - acceptable level of
contaminants present
 Antiseptic – inhibits growth of infectious
agents on living tissue (Chlorhexidine)
 Sterilization - complete destruction or
elimination of all living organisms

Including viruses and bacterial spores
o Always inorganic material
o
When does aseptic technique begin?

It’s always happening!
o
Cleaning of instruments
o
Surgery suite sanitation/disinfection
o
Patient prep
o
Sx team scrub
o
Surgical suite etiquette
 Contamination cannot always be avoided
o
Skin abscess, dental disease
Contamination
 Risk of contamination doubles
every hour under Ax
 Contamination does not mean infection
 Dependent on:

o
Patient health
o
Tissue damage
o
Virulence and quantity of agent
Level of contamination determines:
o
Use of perioperative antimicrobials
o
Degree of asepsis required
Classification of Surgical Procedures
 Clean = non-contaminated, routine, placement of hardware
o
Ex. permanent implants (IM pins), benign laparotomy
 Clean-contaminated = entering a hollow organ
o
Ex. enterotomy, cystotomy
 Contaminated = leakage during Sx or major breach of
aseptic technique
o
Ex. enterotomy, cystotomy
 Dirty = previously ruptured hollow organ or abscess
o
Ex. cutaneous abscess, septic peritonitis, ruptured pyo
Methods of Sterilization
1. Physical Sterilization
Filtration
Radiation
Heat
2. Chemical Sterilization
 Liquid
Gas
Filtration and Radiation Sterilization
 Filtration – microorganisms separated
From liquid or gas materials
o Pharmaceuticals
o Can be placed on IV line or syringe
 Radiation - destruction of microorganism without
significant increase in temperature
o Gloves and suture material
*Filtration and radiation are typically performed by the
manufacturer before shipments
- anything that comes pre-sterilized
- a lot of “one time use” products
- items which cannot be heat sterilized
Heat Sterilization
 Most common sterilization technique
 Destroys bacteria by denaturing their proteins
1. Dry Heat Sterilization
o
High temperatures for a long period of time
2. Wet Heat Sterilization
o
Creating steam under pressure at high
temperatures
o
Ex. Autoclave
Dry Heat Sterilization
 Does not involve moisture (no rust, no corrosion)
 Takes longer than wet heat and requires higher
temperatures (no steam to achieve the higher
temperature)
Ex. 300°f for 2 ½ hours
Wet Heat: Autoclave Sterilization
1.
Pack must be able to withstand heat AND
moisture!
Pre-vacuum sterilizer
 A pump evacuates the air before the steam enters
More even penetration of steam
o Shorter duration
o
2.
Gravity Displacement Sterilizer
 Steam enters the top and forces air to bottom
 Most commonly used type
Autoclave Sterilization (Gravity Displacement)
 Used most commonly for “packs”
Heat = 250 °F minimum
Pressure = 20 PSI
Time = 13 minutes at temp (exposure time)

o
Total cycle =Heat-up time + exposure time
o
Usually 30 - 45 minute cycle
Always use distilled water!
*Every machine is different, refer to the
operator's manual (usually pre-set values)
There should be space between each pack
 Steam should be allowed to flow
around every surface of each pack
 Use racks if sterilizing a lot of packs
Pack Preparation
Proper pack preparation is critical
 Instruments must be clean and dry
 All locking instruments should be unlocked
 Wrap materials must be steam permeable
1. Woven = double thickness muslin
o
Reusable
2. Non-woven =crepe paper or plastic pouch
o
One time use (mostly)
 Many practices double wrap (AAHA)
Pack Preparation
 Peel packs – clear plastic pouches
made of plastic and paper
o
Self-sealing or heat sealed
o
Instrument is placed into pouch with the
handles toward the closed in
o
Pack will be opened from the closed end
Labeling of Packs
 What is in it
 Initials of who prepared it
 Date it was sterilized
*VTI- which patient it is for
Sterility Indicators
 Tape – outside of pack was exposed to steam
 Chemical Indicator Strips- change color when exposed
to steam for adequate time
Examples:
o
Peel packs – indicator on the outside of the paper
o
OK Strip - can be placed in the center of the pack
o
Stickers- can be placed anywhere (mostly for gas)
Sterility Indicators
 Pellet glass – glass ampule containing a
temperature sensitive pellet that melts
between 244-250 °F
 Biological/Culture tests – contain a spore
population of bacteria (usually Bacillus sp.)
o
Takes minimum of 24 hours for results
o
Confirms that microorganisms
were in fact killed if the sample does
not grow anything
Autoclave Quality Control
Performed by technicians- ensures proper technique
 Sterility Indicators
 Must be used in combination, as not just one will
cover all requirements
 Temperature graphs
 Autoclave maintenance - autoclave cleaner
o
Ex. Speed-Clean – mixed in the water
o
Ex. Chamber Brite – powder is sprinkled on the bottom of
cold chamber; cycle is ran without drying
o
Both require a “rinse” cycle to be ran after use
After the Autoclave Cycle
 Packs must cool slowly to prevent condensation which
could:
o Wick bacteria
o Rust metal
o Tear paper
 Let the dry cycle finish completely!
 Door should be cracked to vent slowly ~ 20 minutes
o Opening door wide causes steam to condense inside
the pack
 Don’t leave paper packs in autoclave longer than needed
(makes paper more brittle, easy to tear)
Maintaining Sterile Packs
 The outside is not sterile
 Storage: dust free, dry, well-ventilated, away from
contaminated areas - closed cabinet is safer than open
 Broken sterility: dropped on floor, wet, broken outer
wrap (instruments penetrates paper)

o
Never assume sterility - autoclave again
o
Error on the side of caution
Monitor dates for expired sterility (clinic protocol)
Length of Sterility
Table on page 1163 in CTVT
1. Date related practice: Which one lasts longer?
 Double vs. single wrapped
 Non-woven vs. Woven
 Closed vs. open cabinet
 Heat sealed vs. Self-sealed
2. Event related practice: item is sterile until an
event in which the sterility is broken
Flash Sterilization (Emergency situation)
 Instruments are placed unwrapped in a
perforated metal tray
 270°F
for 3 minute exposure time
 Removed with detachable metal handles and
carried straight to surgery (or huck towel)
 Instruments must cool before use
 Some machines have a preset for this