Principles of Asepsis

Condition of sterility No living organisms are present

Technique to prevent contamination Scrubbing surgical site Scrubbing-in for assistants Sterile surgery techniques Monitoring for sterility breaks

Asepsis

_____________________- 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.

Definitions

___________________- 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.

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Sterilization vs. Disinfection

Sterilization All organisms and spores destroyed

Disinfection Vegetative forms of bacteria destroyed Spores not destroyed

Both used to prepare surgical materials

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

Historical Development of Aseptic Technique

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.

Milestones

Semmelweis is known as the father of medial asepsis.

Lister between deliveries, and Semmelweis between patients. (wash your hands between patients)

_____________________- 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.

Etiology Causing Disease

_________________- 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.

Viruses- living 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

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Factors Affecting Contamination

Health of patient Degree of tissue damage in wound Virulence of infectious agent Number of infectious agents Adherence to aseptic technique

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

Physical Methods of Control of Microorganisms

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)

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Quality Control for Autoclaves

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Gas Sterilization Tape

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 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 Dependent on concentration of gas Dependent on exposure time Dependent on exposure temperature Dependent on relative humidity

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

Specific Instructions for Cleaning Stainless Steel Instruments

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

Use of Autoclave here at VTI

1. Make sure water levels are not low 2. Place items in autoclave, shut door 3. Select witch sterilization process needed,

push button

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.

Storage of Sterilized items

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

When is a pack contaminated?