Ch. 11 Sterilization

Question 1

what is the SAL

Answer 1

sterility assurance level - the probability of a single viable microorganism occurring on a product after sterilization

Question 2

What is TASS

Answer 2

toxic anterior segment syndrome is a severe inflammatory process in the anterior chamber following ophthalmic procedures

Question 3

why is mechanical cleaning the preferred method of cleaning instruments? and what are some types of mechanical cleaners?

Answer 3

facilitates washing and rinsing without the risks of manual cleaning (which often relies on cleaning agents)
ex. ultrasonic, washer decontaminators, washer sterilizers, washer disinfectors

Question 4

how do ultrasonic cleaners clean?

Answer 4

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

Question 5

what is the difference between a washer decontamintor vs a washer disinfector

Answer 5

decontaminators carry no specific claims of antimicrobial efficacy whereas washer disinfectors can achieve high level disinfection
both use circulating water and detergents

Question 6

what count should cotton muslin for wrapping material be?

Answer 6

140 or 270 count

Question 7

why can linens and paper wrapping not be used for the hydrogen peroxide gas plasma or vapor sterilization?

Answer 7

they may absorb the hydrogen peroxide which may make the process less effective

Question 8

what are the most commonly used wrapping materials for ethylene oxide

Answer 8

polyethylene/mylar
polycoated paper
uncoated paper

Question 9

explain the properties of gluteraldehyde

Answer 9

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%

Question 10

explain the properties of ortho-phthalaldehyde (Cidex OPA)

Answer 10

stains skin and tissues but is less irritating than gluteraldehyde
does not require pH adjustment

Question 11

explain the properties of hydrogen peroxide as a chemical sterilizer

Answer 11

concentrations greater than 7.5%

Question 12

explain the properties of peracetic acid as a chemical sterilizer

Answer 12

oxidizing agent
use at 0.2%
irritating to skin and unstable

Question 13

why do we use steam with sterilization

Answer 13

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)

Question 14

what is the typical temperature for a gravity displacement steam sterilizer

Answer 14

121 C or 250 F for 30 minutes (and 15-30 drying)

Question 15

what is the typical temperature for a prevacuum sterilizer unit

Answer 15

132 C or 270 F for four minutes (but AAMI recommends 15 min exposure and 15-30 dry)

Question 16

how does a gravity displacement sterilizer work

Answer 16

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

Question 17

how does a prevacuum steam sterilizer work

Answer 17

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

Question 18

what is a formaldehyde vapor sterilizer

Answer 18

similar to any other steam sterilizer but can use a lower temp (about 65-80 C)

Question 19

what is the recommended temp and duration for dry sterilization

Answer 19

160 C (or 320 F) for 120 minutes

Question 20

what is the recommended temp and duration for a flash sterilization cycle in a gravity dependent autoclave

Answer 20

135 C (275 F) for three minutes with 1 minute of drying time
should be unwrapped!

Question 21

how does ethylene oxide work as a sterilizer

Answer 21

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

Question 22

why does ethylene oxide need an aeration cycle

Answer 22

ethylene oxide will adsorb to many substances like rubber and some plastics

Question 23

what are the concentration, temp, humidity, and temp ranges for ethylene oxide sterilizers

Answer 23

450-1200 mg/L
29-65 C (84-149 F)
45-85% humidity
2-5 hours plus drying time

Question 24

how does ozone sterilization work and what is the temp/duration of a cycle

Answer 24

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

Question 25

how do plasma sterilizers function

Answer 25

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

Question 26

how do vaporized hydrogen peroxide sterilizers work

Answer 26

low temperature 30-55 minutes no toxic residues available as room disinfection units to decontaminate environment

Question 27

how does sterilization by radiation work

Answer 27

cobalt 60 gamma rays or electron accelerators | certain biologicals like bone grafts may be weakened by irradiation

Question 28

what organism is used to test for steam sterilization, plasma, and ozone

Answer 28

Geobacillus stearothermophilus

Question 29

what organism is used for testing ethylene oxide sterilization

Answer 29

Bacillus atrophaeus

Question 30

what is the shelf life for instruments in double layered linen or plastic paper envelopes following steam sterilization

Answer 30

96 weeks

Question 31

what is the shelf life for instruments in cloth wrapping following ethylene oxide gas sterilization

Answer 31

15-30 days

Question 32

what is the shelf life for instruments in paper wrapping following ethylene oxide gas sterilization

Answer 32

30-60 days

Question 33

what is the shelf life for instruments in plastic wrapping following ethylene oxide gas sterilization

Answer 33

90-100 days

Question 34

what is the shelf life for instruments in heat sealed plastic wrapping following ethylene oxide gas sterilization

Answer 34

1 year

Question 35

what is a class 1 sterilization indicator and where does it go?

Answer 35

demonstrates that a package has been exposed to a sterilization process and should be placed on the outside of every package

Question 36

what is a class 2 sterilization indicator and where does it go?

Answer 36

indicator that is used for a specific purpose also called a Bowie Dick indicator. placed inside the pack

Question 37

what is a class 3 sterilization indicator and where does it go?

Answer 37

indicator that reacts to a single parameter of sterilization like just temp or just time. place inside the pack

Question 38

what is a class 4 sterilization indicator and where does it go?

Answer 38

indicator that reacts to multiple parameters of sterilization. placed inside the pack

Question 39

what is a class 5 sterilization indicator and where does it go?

Answer 39

indicator that reacts to all parameters of sterilization. Also called an integrating indicator. Placed inside the pack

Question 40

what is a class 6 sterilization indicator and where does it go?

Answer 40

indicator that reacts to all parameters of a given sterilization cycle (emulating indicator). placed inside the pack