Ch. 11 Sterilization Flashcards
what is the SAL
sterility assurance level - the probability of a single viable microorganism occurring on a product after sterilization
What is TASS
toxic anterior segment syndrome is a severe inflammatory process in the anterior chamber following ophthalmic procedures
why is mechanical cleaning the preferred method of cleaning instruments? and what are some types of mechanical cleaners?
facilitates washing and rinsing without the risks of manual cleaning (which often relies on cleaning agents)
ex. ultrasonic, washer decontaminators, washer sterilizers, washer disinfectors
how do ultrasonic cleaners clean?
utilize the process of cavitation - ultrasonic waves create minute gas bubbles which then implode and create a minute vacuum that facilitates the removal of particles and debris
what is the difference between a washer decontamintor vs a washer disinfector
decontaminators carry no specific claims of antimicrobial efficacy whereas washer disinfectors can achieve high level disinfection
both use circulating water and detergents
what count should cotton muslin for wrapping material be?
140 or 270 count
why can linens and paper wrapping not be used for the hydrogen peroxide gas plasma or vapor sterilization?
they may absorb the hydrogen peroxide which may make the process less effective
what are the most commonly used wrapping materials for ethylene oxide
polyethylene/mylar
polycoated paper
uncoated paper
explain the properties of gluteraldehyde
a chemical disinfectant with reasonable efficacy against bacterial spores but only for prolonged exposure and certain pH
14 day shelf life
starts out acidic but needs to be alkalinated to be effective
minimum effective concentration is 1.0-1.5%
explain the properties of ortho-phthalaldehyde (Cidex OPA)
stains skin and tissues but is less irritating than gluteraldehyde
does not require pH adjustment
explain the properties of hydrogen peroxide as a chemical sterilizer
concentrations greater than 7.5%
explain the properties of peracetic acid as a chemical sterilizer
oxidizing agent
use at 0.2%
irritating to skin and unstable
why do we use steam with sterilization
the water serves as a catalyst and allows us to use lower temps
additionally, heat is transferred from the steam by condensation and not just absorption (like with dry heat)
what is the typical temperature for a gravity displacement steam sterilizer
121 C or 250 F for 30 minutes (and 15-30 drying)
what is the typical temperature for a prevacuum sterilizer unit
132 C or 270 F for four minutes (but AAMI recommends 15 min exposure and 15-30 dry)
how does a gravity displacement sterilizer work
steam is introduced under pressure and because it is lighter than air, stays at the top and forces air out the valve at the bottom
the temperature of the discharged air can be used to evaluate the effectiveness of the process
how does a prevacuum steam sterilizer work
similar to a gravity displacement but there is a pump that removes air before the steam comes in and then the steam is rapidly sucked in
faster than gravity displacement and also very uniform steam
what is a formaldehyde vapor sterilizer
similar to any other steam sterilizer but can use a lower temp (about 65-80 C)
what is the recommended temp and duration for dry sterilization
160 C (or 320 F) for 120 minutes
what is the recommended temp and duration for a flash sterilization cycle in a gravity dependent autoclave
135 C (275 F) for three minutes with 1 minute of drying time should be unwrapped!
how does ethylene oxide work as a sterilizer
unlike heat (which will kill microorganisms through coaulation and denaturation of proteins), ethylene oxide will akylate proteins and nucleic acids which will obstruct cell metabolism and reproduction it is usually mixed with carbon dioxide or hydrochlorofluorocarbon (HCFC) because ethylene oxide by itself is flammable
why does ethylene oxide need an aeration cycle
ethylene oxide will adsorb to many substances like rubber and some plastics
what are the concentration, temp, humidity, and temp ranges for ethylene oxide sterilizers
450-1200 mg/L
29-65 C (84-149 F)
45-85% humidity
2-5 hours plus drying time
how does ozone sterilization work and what is the temp/duration of a cycle
O3 has a loosely bound third oxygen molecule that will readily oxidize other molecules to cause destruction of microorganisms
30-35 C for four hours
how do plasma sterilizers function
use electromagnetic energy to create a plasma phase from a vapor of hydrogen peroxide, oxygen, or peracetic acid/hydrogen peroxide mix
the plasma contains reactive products like free radicals
expensive
some forms require no aeration - no toxic residues
the cycle is done at 45-50 C for 28-75 minutes
good for moisture or heat sensitive items but not for linens, liquids, wood
they need special synthetic packaging and container trays
how do vaporized hydrogen peroxide sterilizers work
low temperature
30-55 minutes
no toxic residues
available as room disinfection units to decontaminate environment
how does sterilization by radiation work
cobalt 60 gamma rays or electron accelerators
certain biologicals like bone grafts may be weakened by irradiation
what organism is used to test for steam sterilization, plasma, and ozone
Geobacillus stearothermophilus
what organism is used for testing ethylene oxide sterilization
Bacillus atrophaeus
what is the shelf life for instruments in double layered linen or plastic paper envelopes following steam sterilization
96 weeks
what is the shelf life for instruments in cloth wrapping following ethylene oxide gas sterilization
15-30 days
what is the shelf life for instruments in paper wrapping following ethylene oxide gas sterilization
30-60 days
what is the shelf life for instruments in plastic wrapping following ethylene oxide gas sterilization
90-100 days
what is the shelf life for instruments in heat sealed plastic wrapping following ethylene oxide gas sterilization
1 year
what is a class 1 sterilization indicator and where does it go?
demonstrates that a package has been exposed to a sterilization process and should be placed on the outside of every package
what is a class 2 sterilization indicator and where does it go?
indicator that is used for a specific purpose also called a Bowie Dick indicator. placed inside the pack
what is a class 3 sterilization indicator and where does it go?
indicator that reacts to a single parameter of sterilization like just temp or just time. place inside the pack
what is a class 4 sterilization indicator and where does it go?
indicator that reacts to multiple parameters of sterilization. placed inside the pack
what is a class 5 sterilization indicator and where does it go?
indicator that reacts to all parameters of sterilization. Also called an integrating indicator. Placed inside the pack
what is a class 6 sterilization indicator and where does it go?
indicator that reacts to all parameters of a given sterilization cycle (emulating indicator). placed inside the pack
