Chapter 10 Sterilization BST

the cycles commonly recommended by steam sterilizer manufacturers are:

-dynamic air removal steam, 4 minutes at 270 F (132c) & 28-30 pounds per square inch (PSI) -dynamic air removal steam, 3 minutes at 275 F (135c) & 28-30 PSI -Gravity displacement steam, 30 minutes at 250 F (121c) & 15 PSI -Gravity displacement steam, 15-25 minutes at 270 F (132 c) & 27 PSI Gravity displacement steam, 10 minutes at 275 F (135 C) & 30 PSI

Hydrogen peroxide ozone sterilization:

A low-temperature sterilization method that uses both vaporized Hydrogen peroxide and a small amount of ozone in a multi-phase process.

The spore used for dry heat biological indicators is:

Bacillus athophaeus

Incubation of BIs

Biological indicators should be placed in an incubator or auto-reader at the temperature recommended by the BI manufaturer. Typical temperatures are 55c to 60 c or 131 F to 140 F

Dynamic air removal cycles are used in?

Prevaccum sterilizers and in steam-flush pressure-pulse (SFPP) sterilizers.

exhaust phase

Steam is exhausted from the sterilizer through the chamber drain line

To avoid superheating:

The test pack should never be placed directly on the floor of the chamber or an instrument tray or wire basket that has been turned upside down.

For hydrogen peroxide ozone sterilization there is no need for what?

a drain or special ventilation, just electric power and oxygen. After sterilization there is no need for aeration because residual chemicals are converted back to water vapor and oxygen, which are returned to the atmosphere at the end of the cycle.

What are wet packs?

a wet pack is a package that has visible moisture, such as droplets, on the outside or inside, such as a wet towel or tray liner, moisture on the instruments, or visible inside the set.

Process indicators (type 1)

also referred to as chemical indicators. An example is indicator tape. is used to differentiate packages that have been processed in a sterilizer from those that have not been processed.

Packages can be labeled with?

an expiration date or an event-related dating statement.

Routine load release of implant loads:

an external CI should be used on the outside of each package unless the internal CI can be seen through the package and thus can be used to verify that the package has been processed. A type 5 integrating indicator should be used in each load containing implants.

Emulating indicators (Class 6 indicators)

are designed to react to all critical variables of a specified sterilization cycle. They should only be used in the specific cycle for which they are labeled.

Integrating indicators (type 5)

are designed to react to all of the critical variables of the specific sterilization process that they are designed to monitor.

Multi-variable indicators (type 4)

are designed to react to two or more of the variables of the sterilization process that they are designed to monitor. They may be used as external chemical indicators. Most show an acceptable endpoint by a color change.

Indicators for specific tests (Type 2)

are used in certain test procedures, such as the Bowie-Dick test for the air removal performance of pre-vacuum sterilizers.

What is vital to good sterilization outcomes?

cleaning and decontamination

Phases of the steam sterilization cycles

conditioning phase sterilization/exposure/holding phase exhaust phase drying phase temperature and pressure

Prevaccum sterilizers remove air by?

drawing a series of vaccums with an injection of steam between each vaccum pull. this method is more efficient than gravity displacement cycle.

What are they two types of steam cycles?

dynamic air removal and gravity displacement

lot control numbers are used to

enable recall following sterilization failure

In a gravity displacement sterilizer drying takes place by____?

evaporating resulting from the heat in the chamber walls and is thus much less efficient.

sterilization/exposure/holding phase

exposure temperature is maintained for the prescribed amount of time. holds the temperature for the amount of time needed.

The leak test is ordinarily programmed on the sterilizer cycle panel and is typically run in an empty chamber as ________ of the day before the Bowie-Dick test.

first cycle

The biological indicator for low-temperature hydrogen peroxide sterilization cycles?

geobacillus stearothermophilus

The biological indicator for hydrogen peroxide ozone sterilization is?

geobacillus stearothermophilus. It should also contain a chemical indicator.

For Ehylene oxide to penetrate cell walls microorganisms must be_____

hydrated

What sterilizer has a large chamber with a load capacity of up to 75 pounds?

hydrogen peroxide ozone sterilization

A tracking system should be in place that permits recall of devices used on high-risk tissue and patients. This tracking system should permit:

identification of the patient on which the devices were used, the date they were used, the procedure performed, and the surgeons name.

sterile packs are most vulnerable to contamination:

immediately after sterilization, when the packaging is still hot. Sterilized items should remain on the sterilizer cart, untouched, until they are completely cooled.

Wet packs can be caused by?

improper insulation of steam lines malfunction of traps in the steam line or no traps in the steam line malfunction of the drain check valve or no drain check valve steam contact with a cold load too much water in the steam produced at the boiler incorrect loading incorrect packaging materails

Healthcare facilities are now using ______________ to determine the temperature of the packs.

infrared thermometers.

Loading the sterilizer with mayo trays

instrument sets in solid-bottom mayo trays or mayo trays with small holes should be tilted on their edge (side) to permit condensate from running off.

the steam sterilizer has an internal chamber surrounded by an?

insulating jacket. This jacket provides heat inside the chamber to prevent condensation from forming on the chamber walls.

Conditioning phase

introduces the steam, gets steam ready for sterilization

Table-top sterilizers

is a compact steam sterilizer that has a chamber volume of not more than two cubic feet and that generates its own steam when distilled or deionized water is added by the user.

Low-temperature hydrogen peroxide sterilization:

is a low temperature sterilization process that uses vaporized hydrogen peroxide as the sterilant.

What is sterility?

is the abscence of all forms of microbial life including bacterial spores

Physical monitoring

is the observation of the charts, gauges, and printouts. at the end of each sterilization cycle, the sterilizer operator should review the printout and verify the time, temperature, and pressure were correct for the load contents.

Bowie-Dick Test

is used to detect air leaks, inadequate air removal, inadequate steam penetration, and the presence of noncondensable gases (air, gases from boiler additives). Is performed daily for dynamic air removal cycles of pre-vacuum sterilizers.

The jacket helps with what?

it helps to seperate water droplets from the steam before the steam is injected into the chamber.

Low temperature gas plasma sterilization

it is a quick low-temperature process that uses a combination of hydrogen peroxide vapor and gas plasma to effectively and safely sterilize packaged devices.

Why is steam sterilization the most common method for sterilizing?

it is fast, effiient, low in cost, readily available, and non-toxic.

Frequency of biological monitoring:

it is recommended that biological monitoring of steam sterilization cycles be performed routinely (weekly, preferably daily) for every load containing implants, and for qualification testing.

system 1E liquid chemical sterilant processing system

liquid chemical sterilant. only labeled for immersible items. is a point of use system and the processor should be located as close to the point of use as possible.

to present the greatest challenge to the sterilizer all process challenge devices or PCD's should be placed?

on the bottom shelf of the cart or rack, directly over the drain line. The bowie dick test is also placed in this location.

Steam sterilization and other sterilization processes are generally designed to kill____

one million bacterial spores

What are the three parameters of steam sterilization?

saturated steam under pressure, time, and temperature.

When loading wrapped items in the sterilizer they should never be?

stacked

Gravity displacement depends on?

steam passively displacing air, which exits through the drain line; usually require longer exposure times.

IUSS are not meant for?

storage and sterile items.

Too much steam can cause_________ and not enough steam can cause______

super heating and wet packs.

temperature and pressure phase

temperature and pressure are interrelated. for each temperature there is a necessary pressure to reach that temperature. the higher the temperature the higher the pressure needed.

Because IUSS does not employ a drying phase in the cycle, the items____

will be moist/wet after the cycle ends. this is why IUSS should only be used under emergency conditions when there is insufficient time to use the traditional terminal sterilization methods, which include drying.

Table tob sterilizers usually have a limited number of cycles these include:

wrapped instruments/packs, paper-plastic pouches, unwrapped instruments, and handpieces. Usually of the gravity displacement type but prevacuum and SFPP table-top sterilizers are also available.

the control BI should always turn:

yellow or fluorescence indicating that the spores were able to grow or produce fluorescence if they survived the sterilization process.

The sterilizer's heat-sensing thermometer is located in the:

Drain line, which is the coolest part of the sterilizer.

Ethylene oxide sterilization

EO is a gas at room temperature, with a boiling point of 10.7 C or 51.3 F

Low-temperature sterilization methods include:

EO sterilization, Low-temperature gas plasma sterilization, hydrogen peroxide sterilization, and hydrogen peroxide-ozone sterilization.

when loading the sterilizer with textile packs they should be?

Textile packs should be placed on their side to facilitate air removal and steam penetration.

Steam sterilization is?

accomplished by saturated steam pressure, a process similar to what happens in a pressure cooker

For ethylene oxide sterilization what spore should be used for the biological indicators?

bacillus atrophaeus

Test container:

biological indicators and type 4, type 5, and type 6 chemical indicators should be placed in the areas that create the greatest challenge to steam penetration and air removal. Five biological indicators should be assembled for placement inside each container.

Steam kills microorganisms by_______ the protein

denaturing (coagulation)

The basic parameters of EO sterilization are:

gas concentration, exposure time, humidity, temperature, and in the case of sterilizers that use EO mixtures, pressure.

Super heating of steam occurs when?

saturated steam at any given temperature is subjected to a higher temperature. this occurs when heat is added to dry steam in the absence of water.

The control BI is used to verify:

that the spores were viable before they were sterilized, that the medic can promote the growth of the test spores, that the storage conditions were correct, and that the proper temperature was used for incubation (if indicated).

Using whiteout or using a marker to cross off incorrect information is prohibited because it could suggest that the records were altered. What should the operator do instead?

the operator should draw a line through the incorrect information and initial it, and then record the correct information.

When the sterilizer is turned on?

the steam enters the jacket and remains there until a cycle is initiated, the chamber is always warm when the steam supply is on. it is for this reason that the steam supply should be turned off when the chamber should be cool for cleaning purposes.

Steam sterilizers using boiler-generated steam

the sterilizer needs a dedicated supply of steam. the steam is generated inside a boiler. The feed water in the boiler must be treated with chemicals to minimize the presence of potential potnetial contaminants in the steam and to prevent damage to the boiler or the steam lines.

When loading the sterilizer with rigid sterilization containers?

they should be placed flat with sufficient space (approximately one inch or 2.5cm) between each container to permit air removal and steam penetration.

When loading the sterilizer with paper-plastic pouches?

they should be placed on their edge (side) with the clear side of one pouch facing the paper side on the next pouch. paper-plastic pouches should be placed in a wire basket or peel-pack seperator.

What are the parameters for low-temperature hydrogen peroxide sterilization cycles?

time, temperature, and hydrogen peroxide

What are the parameters of low-temperature gas plasma sterilization cycles?

time: varies with the sterilization model temperature: 113 F to 131 F (45-55 c) hydrogen peroxide gas plasma.

Control BIs

whenever a test BI is used, a control BI (one that is not sterilized) is needed. The SPD technician should verify that the control BI has the same lot control number as that printed on the BI PCD test pack or the BI test vial. If not, the test BI result is not considered valid.

sterility assurance level (SAL)

10 to the -6

Typical minimum aeration times and temperatures are?

122 F (50 c) for 12 hours of 140 F (60 c) for 8 hours.

The temperature of dry heat sterilizer cycle must be increases to:

160 C to 170 C (320 F to 328 F) for an exposure time of 2-4 hours.

AAMI ST79 currently recommends processing instruments potentially contaminated with prions using a cycle have a minimum exposure time of:

18 minutes at 273 F (134 c) in a pre-vacuum steam sterilizer or 60 minutes at 250 F (121 c) in a gravity displacement steam sterilizer immediate use steam sterilizers should not be used

the cycle specified for the bowie-dick test is run, or the sterilizer is set to run for ___ to ______ minutes at ______ or ______ with no drying time. If the sterilizer cannot be set to 3 1/2 the cycle should be run for four minutes.

3-3 1/2 270 F (132c) or 273 (134c)

A 1- log reduction means that _____ of the microorganisms have been killed

90%

One measure of steam quality is the relative dryness of the steam. Ideally the incoming steam should be between ___ and ___ dry saturated steam.

97% and 100%

Testing of rigid sterilization container systems:

AMMI recommends that rigid containers be biologically tested before purchase and annually to verify that the sterilizes is able to sterilize inside the containers.

Drying phase

After the steam has been exhausted, the sterilizer goes into the - of the cycle which typically lasts about 30 minutes. In a gravity displacement cycle, the heat in the chamber walls causes moisture to evaporate. to achieve drying in a dynamic air removal steam cycle, filtered air is drawn into the chamber

ethylene oxide kills microorganisms by a process known as?

Alkylation

the boiler should be located?

As close to the sterilizers as possible, and there should be dedicated steam lines to supply constant steam pressure so that sterilizers can be properly operated at times of peak demand. The pressure requires is 60-80 psig (pounds per square inch).

BI Test Results:

Depending on the BI used the color of the sterilized BI should be unchanged or show no fluorescence, signifying that the spores were killed.

immediate-use steam sterilization

Formerly called flash sterilization. Is appropriate in emergency situations, such as a when one of a kind item is dropped on the floor during surgery.

Biological monitors for table top sterilizers use the same spore as that used to test larger steam sterilizers which are:

Geobacillius stearothermophilus

The biological indicator for low temperature gas plasma sterilization cycles is the spore:

Geobacillus stearothermophilus

in a dynamic air removal steam sterilizer, the drying takes place in _______?

HEPA-Filtered Air

loading the sterilizer with heavier sets

Heavier sets should be placed on the bottom rack because they tend to produce more condensate.

Test procedures for routine biological monitoring of immediate use steam sterilization cycles:

IUSS sterilization cycles should be monitored at least weekly, preferably daily with a BI. AORN recommends that when a BI is run, a type 5 integratingIn indicator or a type 6 emulating labeled for the cycle being tested should be included.

What devices are not compatible with hydrogen peroxide ozone sterilization?

Implants, glass or plastic ampoules containing liquids, devices made of natural rubber, textile fabrics, and lumened devices.

In gravity displacement cycles....

Incoming steam displaces residual air through the drain at the bottom of the sterilizer chamber:

chemical monitoring

Involves the use of external chemical indicators to verify that a load has been subjected to a sterilization process

Biological monitoring

Is intended to verify that the sterilization conditions within the load were adequate to kill a known number of bacterial spores. the only way to measure the lethality of a sterilization process.

For sterilization to occur, steam must:

Make direct contact with all surfaces of the device. air and other noncondensable gases are the enemies of steam sterilization process because air and steam do not mix.

Is a bowie dick test required for gravity displacement cycles?

No, because there is no mechanical air removal in a gravity displacement cycle.