Principles of Asepsis
Asepsis
 Condition of sterility
 No living organisms are present
 Technique to prevent contamination
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Scrubbing surgical site
Scrubbing-in for assistants
Sterile surgery techniques
Monitoring for sterility breaks
Definitions
 _____________________- is any process that
detrimentally interferes with the functioning of an
organism.
 _____________________- is a living organism too small to
be seen with an unaided eye. Pathogens are
__________________ capable of causing disease.
 _______________________- is the relationship between a
parasite and its host that may cause disease if the
parasite is a pathogen.
 ___________________- refers to the microbes that are
normally found in healthy animals, such as E.coli of the
intestinal tract.
 ____________________- is the sum of all factors contributing
to the ability of an animal to overcome invasion by pathogens.
 ____________________-refers to the presence of pathogens
or their toxic products in the blood or tissues of the patients,
and asepsis refers to the complete absence of living
pathogenic microbes.
 _________________- is the term used to describe the
condition of any item that has undergone a cleansing
procedure that result in the complete absence of
microbes including spores. Most commonly performed
in veterinary medicine with moist heat, gas, radiation,
and chemicals.
 __________________- refers to the body of techniques
that are designed to maintain an object or area in a
condition as free of all microorganisms as possible
 _________________- refers to the techniques used to
reduce the number of microbes in general and the
transmission of pathogens in particular.
 In surgical applications, any item that has not been
sterilized is considered _____________________
 _______________- is any cleansing measure intended to
prevent disease and promote health, including the
routine cleaning of such items as cages, floors, buckets,
and sinks to remove soil, saliva, urine, and feces.
Example- washing hands
 ________________ is very much like sanitation that is
applied to inanimate objects like floors, tables, etc., but
is stronger and simple sanitation and is intended to
destroy or inhibit the growth of microorganisms
 Cidal Static-
 ______________- is the use of a process to rid an object
of all living microbes including spores.
 Surgical patients, who may be subjected to considerable
stress because of the condition requiring surgery, must
be able to withstand the trauma that occurs during
surgery. This trauma can weaken a patient to the extent
that the additional stress of an infection acquired during
or after surgery could cause an unnecessary fatality.
Sterilization vs. Disinfection
 Sterilization
 All organisms and spores destroyed
 Disinfection
 Vegetative forms of bacteria destroyed
 Spores not destroyed
 Both used to prepare surgical materials
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Historical Development of Aseptic
Technique
 Until the 19th century, two factors that prevented the
development of surgery were:
 A. the lack of anesthetics and analgesics
 B. the inability of medical personnel to prevent the high
incidence of postsurgical infection
Milestones
 1861- Semmelweis believed transmission of infectious disease
could be controlled by hygienic measures and use of
disinfectants
 1868- Villemin- demonstrated transmission of tuberculosis form
animal to animal
 1870- Lister- used carbolic acid as disinfectant in surgery
 1892- Killbourne and Smith- proved the theory of intermediate
host transmission (Texas Fever)
 1898- Ehrlich- demonstrated antigen/antibody (humoral) theory
of immunity
 1876- Koch- isolated Bacillus anthracis and proved it as the
cause of anthrax
 1927- Fleming- discovered penicillin
Milestones
 Louis Pasteur- disproved the theory of spontaneous
generation, removing on the major blocks to the
development of the theory of aseptic technique.
(also vaccines for anthrax, process of pasteurization, rabies
prevention)
 Joseph Lister- noted that wound infections were caused
by microorganism. He used dressing soaked with phenol
, he believed it would destroy microbes causing a
significant decrease in the incidence of postsurgical
infections in his patients.
 Lister is known as the father of surgical asepsis.
 Semmelweis is known as the father of medial asepsis.
 Lister between deliveries, and Semmelweis between
patients. (wash your hands between patients)
Etiology Causing Disease
 _____________________- the most animal like of the
protists, range in size from those just visible to the naked
eye to those that are almost as small as bacteria. All are
motile in at least one stage of their life cycle. They form a
cyst at some point of the life cycle that is relatively
resistant to destruction.
 ______________________- non-chlorophyll bearing
plants identified as either molds or yeasts. Because they
do not produce chlorophyll and cannot synthesize their
own food, they must exist as parasites.
 _________________- shapes: coccus (round), bacillus
(rod), or spirillum (spiral) classified as gram positive or
gram negative based on the staining of the cell wall. The
most common etiology we deal with on a daily basis.
 _____________________- small group of microbes that
are obligate intracellular parasites, being totally
dependent on cells of the host tissues. Use arthropods
as a vector or host.
 Chlamydiae- very little is known about this group, other than
they resemble rickettsia in many ways. Better known for
infections in birds
 Mycoplasmas- smallest free-living organisms discovered to
date. You will hear about more of these to come. Many
protozoa are now being reclassified as mycoplasmas i.e.Haemobartonella felis, once classified as a protozoan, is not
renamed Mycoplasma haemophilus. They are sometimes
referred to as pleuropneumonia- like organisms (PPLOs).
They have no cell wall and are relatively resistant to
antibiotics.
 Virusesliving cells are characterized as containing both
DNA and RNA and possessing at least some
enzyme systems that carry on metabolic
processes necessary for growth and reproduction.
Viruses have either DNA or RNA, but not both
Factors Affecting Contamination
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Health of patient
Degree of tissue damage in wound
Virulence of infectious agent
Number of infectious agents
Adherence to aseptic technique
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Physical Methods of Control of
Microorganisms
 1. Dry Heat- (2 hours at 320F) kills by protein oxidation
 A) drying- microorganisms need water to complete their cycle
of growth and reproduction. The removal of water form the
immediate environment will inhibit the growth of bacteria,
protozoa, and fungi
 B) Incineration- the complete destruction of material during
incineration limits this method of sterilization to contaminated
items that are of no value or that cannot be reused
 C) Hot air ovens- low cost in terms of both purchase and
running. But includes extended time required and the fact that
many items do not withstand repeated dry heat exposure
 Kills by protein oxidation
 2. Moist Heat- kills by coagulation of cellular protein
 A) Hot water- water 60 degrees C or above is an effective
sanitizing agent. (laundry, dishwashers) The mechanical
effect of agitation or scrubbing increases the sanitizing
effect, as does the addition of a detergent
 B) Boiling- the maximum temperature achieved is 100
degrees C. Some bacterial spores and viruses resist
destruction at this temperature for extended periods,
boiling cannot be considered truly effective in sterilization
 C) Free-flowing steam- known as live steam is similar to
boiling because the max temp is 100 degrees C.
 D)Steam under pressure- autoclave and the method of choice.
Some viruses and the spores of a few saprophytic and parasitic
bacteria can withstand temperature of 100 C for a prolonged
period. However if the pressure is increased, the temperature
can be raised, and all microorganisms can be killed. 15psi,
250F, 30 minutes.
 Larger packs: 30-45 minutes at 121° C
 Emergency (flash sterilization): 3 minutes at 131° C (270F)
Quality Control for Autoclaves
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Gas Sterilization Tape
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 E) Ultrasonic vibration- are sound waves above the
frequencies hear by humans. It was though this would be
useful mean of sterilization, but has been proven not true.
Used after surgery to remove blood, and other gross
contaminants from surfaces of instruments that are otherwise
inaccessible (hinges) prior to autoclaving
 3) Radiation A) Ultraviolet light- Sunlight has been long recognized as
having antimicrobial qualities. UV light with a wave length of
2500-2600- angstroms is partially absorbed by components
of microbial protein which can destroy nucleic acids in some
bacteria, which leads to cell death. Same surfaces lack the
ability to absorb UV light
 B) Ionizing radiation- radiation of shorter wavelengths are
still being studied for potential use, i.e. x-rays, neutrons,
alpha, beta, and gamma rays, and cathode rays
 4. Filtration
 Gases or liquids may be purified by passing them through a
substance that retains undesirable components but allows the gas
or liquid to pass unaltered. Example- Sterrad 50, a hydrogen
peroxide sterilization unit. Safe $$$$
 Agents inactivated
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Mycobacteria
Bacterial spores
Fungi
Viruses
 Timing
 Approximately 1 hour
 Requires no aeration
 5) Chemical Methods
 A) Aldehydes
 1) Formaldehyde – can be made in a 37% solution, but is
hard to get, carcinogenic, and pungent in odor. Not
practical
 2) Glutaraldehyde (Cidex Plus) ideal and only true
chemical method for sterilization of instruments.
Instruments must stay submerges for 24 hours
 B) Alcohol- if used properly, some members of this group
of organic compounds exhibit strong bactericidal
properties because of their ability to coagulate protein.
Do not use repeatedly on skin (cytotoxic, painful)
because it removes the normal oils.
 C) Oxidizing agents- halogens like iodine, chlorine, fluorine,
and bromine. Bactericidal making them a good disinfectant
and antiseptic agent.
 Nolvasan- chlorhexidine
 Betadine- Povidone-iodine- common scrub, causes skin
irritation, and acute contact dermatitis.
 Bleach- sodium hypochlorite
 D) Surfactants and detergents
 1- Soaps- cleaning agents with limited disinfectant capabilities.
Action is mechanical.
 2- Cationic detergents- Quaternary ammonium compounds
(benzalkonium chloride) are surface active chemical agents
that are effective against both gram positive and gram
negative bacteria. Roccal D- disinfectant, Zephiran- antiseptic.
 E) Phenolic derivatives- phenol like carbolic acid used by Lister.
Is used as a standard in determining capabilities of other
agents. Is corrosive to the skin
 Antiseptic, also disinfectant, but is replaced by safer agents
today.
 F) Chemical sterilization using gases
 Ethylene oxide- poisonous, colorless, irritating to the skin
and mucous membranes, explosive, flammable. Longer
exposure period as compared to autoclave. But prevents
the melting of rubber and plastic items, that before could
not be sterilized. Anprolene Sterilizer.
 Effectiveness
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Dependent on concentration of gas
Dependent on exposure time
Dependent on exposure temperature
Dependent on relative humidity
Specific Instructions for Cleaning
Stainless Steel Instruments
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1) Soak the instruments in cold water
2) Make sure the ratchets are unlocked
3) Wash and clean with brush in grooves
4) Rinse each instrument in Miltex instrument cleaner
5) Place instrument in ultrasonic cleaner – 15-20 minutes
6) Remove and rinse in cold water to remove soap
7) Place in milk bath for a few seconds
8) Remove from milk bath and blot dry
9) Place in proper area or pack
Use of Autoclave here at VTI
 1. Check reservoir for water, then add
items
 2. Fill chamber with water until some
spills over edge
 3. Close and latch door, add 5 minutes
and wait, when buzzer goes off add 30
minutes
 4. Unlatch door handle (but do no open
door!)
 5. Press and hold “fill/vent” button until
door pops inward (scares Mrs. Singer)
 6. Open door and let items cool
 1. Make sure water levels are not low
 2. Place items in autoclave, shut door
 3. Select witch sterilization process needed, push
button
Storage of Sterilized items
 1) area free of non-sterilized items, or at least on a
different shelf
 2) closed cabinets are preferred to open.
 3) Try to rotate packs
 4) Packed double wrapped textile or single wrapped
two crepe paper stored in a dust free and insect free
cabinet are sterile for 6 weeks.
When is a pack contaminated?
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If….
Pack becomes wet outside the autoclave
Tape sealing the pack is broken or loose
The date of the processing is missing or out of date
Punctures or rips occur in the outer wrap
The pack has been dropped on the floor