Chapter 15 High Temperature Sterilization

340 F (170c)

1 hour

Unloading the steam sterilizer

1. Open the sterilizer door according o protocol. 2. Load should be free from ANY VISIBLE LIQUID 3. Anything wet is considered contaminated. 4. Don't touch anything that has just come out 5. Don't handle until cool (usually 30-60 minutes)

Advantages of dry heat

1. Sterilizes items steam cannot. 2. Won't erode the surface of glass. 3. not corrosive to metal

Factors & Conditions that impact sterilization

1. Type of microorganisms present 2.Number of microorganisms (bioburden) present. 3. Amount of protection the medical device provides.

Sterilization log information

1. date & time of the sterile load 2. load control number 3. specific items sterilized (quantity&description of the items) 4. exposure time,temperature,pressure 5.results of the biological testing 6.response of the chemical indicator placed in the biological indicator test pack 7.results of bowie dick

Disadvantages of dry heat

1. difficult to control 2. high temperatures can damage materials 3.slow/uneven penetration 4.long exposure time 5.limited packing materials available 6.not suitable for rubber and sterilized fabrics

Packaging materials suitable for hot- air convection sterilizers

1. heat resistant glass 2. stainless steel pans 3. cotton muslin (not to exceed 400 degrees) 4. aluminum foil 5. nylon films

Advantages of steam sterilization

1. low cost 2.sterilization cycles are fast 3.relatively simple technology 4.leaves no chemical residue 5.sterilizers come in many sizes.

300 F (150 C)

2 1/2 hours

320 F (160 C) * most widely used temperature for dry heat

2 hours

How much space should be between the discharge line and drain funnel to the floor in the sterilizer?

2-3 inches between

2 most common temperatures for steam sterilization

250 degrees and 270-275 degrees.

High-speed sterilizer temperature

275 degrees

285 F (140 C)

3 hours

Alternative time/temp for dry heat sterilization 356 F (180 C)

30 mins

250 F (121 C)

6 hours, preferably over night

Bowie Dick Test

A class 2 chemical indicator. This evaluates the efficiency of air removal in the steam sterilizer. The warm up cycle should be ran fast. Tests are also performed after the initial relocation, malfunction, process failures, and major repairs.

Conduction

A heat transfer method in which heat is absorbed by an item's exterior surface, and passed inward to the next layer.

Gauge pressure(steam sterilizer)

Absolute pressure (-) atmospheric pressure 14.7 psi at sea level

Basic procedures for loading a sterilizer

Allow for proper steam circulation and avoid overloading. Packages should be placed efficiently for effective air removal. Use an absorbent shelf cover to prevent dripping. Don't use non-woven..(they don't absorb moisture) Allow adequate space to facilitate air removal and drying. Position solid bottom items so that water and air don't get trapped.

Conduction (solids)

(dry heat sterilization) Transmission of heat from one part to another part of an item.

Convection (liquids and gases)

(steam sterilization) Transfer of hear from one point to another as the gas or liquid circulates.

Biological test for steam sterilization

Biological indicators consist of Beobacillus Stearthermophilus. 1. It's the only process monitoring device that provides a direct measure of process lethality. 2. They're intended to demonstrate that all required conditions were adequate to achieve sterilization. 3. Run BI at least weekly but prefer daily and w/every implant load. (if results are negative .. means adequate sterilization conditions)

Class 2

Bowie dick tests

Chemical Integrators Classifications

Class 1- Monitor internal & external sterilization conditions. Class 2-Monitors the air removal (Bowie Dick) done every day. Class 3-Single parameter indicator that reacts to one of the critical parameters. Class 4-Multi parameter indicator that reacts to 2 or more critical parameters. Class 5-Integrating indicators designed to react to all the critical parameters.

Routine sterilizer maintenance

Clogged drain strainers can impede air removal. Wipe the door gasket and inspect for signs of wear and defects. Routine clean sterilizer carts, carriages and baskets. Inspect recording devices, paper charts, and printer paper. Clean the sterilizer chamber according to manufacturer recommendations. Check the chamber drain strainer daily. Clean and check the door gasket daily.

4 main steps in the steam sterilizer cycle phase

Conditioning, exposure, exhaust, drying.

The 3 most common methods of heat transfer

Conduction, Convection, and Radiation

Conditions for effective sterilization

Contact, time, temperature, and moisture.

Dry heat sterilization

Dry heat is a relatively slow-acting sterilizing agent. Requires higher temperatures than other methods. * Only used when direct contact of the material w/ the steam is unattainable.

Table top sterilizers

Frequently used in clinics and dental offices. Operating temperature should reach 250 degrees.

Absolute pressure (steam sterilizer)

Gauge pressure (psi) machine produced + atmospheric pressure 14.7 psi at sea level

Basins & Basin sets

Graduated nested basins should differ in diameter by at least once inch. Weight shouldn't exceed 7 pounds. Prepared in the same direction.

Types of dry heat sterilizers

Gravity convection & mechanical convection.

Dry heat phases

Heat up, exposure, cool down..

Class 5

Integrating indicators designed to react to all critical parameters over a specified range of sterilization cycles.

Problems if the steam isn't saturated

Items in the sterilizer will remain dry and the microorganisms cannot be killed as readily under wet conditions. Items will remain "cool" much longer especially if wrapped.

Components of the Steam Sterilizer

Jacket-surrounds the sides top & bottom. Steam circulates in this space. Door-weakest part of the sterilizer. has a safety locking mechanism. Gasket-maintains a tight seal around the door that prevents steam from escaping and entering the chamber. Chamber drain-located at the front, must be cleaned daily. Thermostatic trap-located in the drain line and measures the steam temperature, controls the flow of air. Gauges and controls-provide a visual and printout of cycle.

temperature for dry heat

Minimum of 320 degrees for 2 hours.

Class 4

Multi-parameter indicators that react to two or more critical sterilization parameters, and that indicate exposure to a sterilization cycle at stated values of those parameters.

Frequent causes of steam contact failures

Not cleaned properly, packages wrapped too tightly, loads too crowded, positioned incorrectly, clogged drain strainer...

Causes of wet packs

Packs that were improperly prepared or loaded for sterilization become wet packs. Pack density can also increase the incidence of wet packs. *wet packs must be documented and returned for examination.

Paper/plastic pouches usage

Paper/plastic pouches should be used for small low-profile items such a clamps or scissors.

Exposure (phase)

Pressure and steam temperature rise, once it reaches the temperature time starts.

Controlling wet packs

Wet packs may occur if a steam sterilization process is used. Packages are considered wet when there is moisture (dampness or puddles) Wet packs=considered contaminated.

275-278 F (135-137C)

for 18 minutes in a prevaccum or porous load unit

250 F (121c)

for 4 1/2 hours in a gravity displacement unit.

270F (132C)

for one hour in a gravity displacement unit.

Load control #

label info on sterilization packages, trays, or containers that identifies the sterilizer , cycle run, and date of sterilization.

Preparation of specialty items

oils and powders are to be packed less than 1 ounce and less than a quarter inch deep. Impregnated gauze strips should be placed in a stainless steel container and covered with a petroleum jelly or other oil based liquid. Depth shouldn't exceed one-half inch. Glass syringes must be thoroughly dry. they may be sterilized fully assembled. needles must be thoroughly dry and may be fully assembled. make sure it can withstand the high heat.

Minimum cycle times for gravity-displacement steam sterilization cycles

unwrapped items Exposure time at 270 degrees and 275 degrees =3 minutes. drying time =0-1 minute others can take 10 minutes

Convection

The process of heat transfer by the circulation of currents from one area to another.

Flash sterilization

The process of sterilizing an item that is not packaged.

Terminal sterilization

The process of sterilizing an item that is packaged.

Physical monitoring

These monitors include time, temperature, and pressure. They help monitor the cycle and to recognize if there are any issues with the sterilizer. If there is a malfunction found, the load =unsterile

When loading a steam sterilizer , items with solid bottoms should be?

They should be placed on edge.

Impregnated gauze strips may be sterilized using which type of sterilization?

They should be sterilized by dry heat.

Cause of CJD

This is caused by prions. And can affect the brain as well as cause the brain to degenerate.

Components of a print out cycle

This receipt includes the time, temperature, and pressure.

Radiation (radiation sterilization)

Transfer of heat from one object to another without warming space between the objects.

Preparing devices & packs for steam sterilization

Use appropriately sized trays for instruments, use only non-linting materials when assembling trays and sets, remove stoppers from clamps etc, position items correctly to allow sterilant contact, complex items prepared /sterilized according to instructions.

Steam-flush pressure -pulse sterilizers

Uses gravity to remove air from the chamber. As steam enters the gravity sterilizer chamber, cooler air is forced out through the chamber drain.

Drying (phase)

Uses the heat of the chamber walls as well as heated filtered fresh air.

Mechanical convection

Utilizes a blower system to ensure even heating throughout the cycle.

What is the most efficient type of dry heat sterilization?

The mechanical convection sterilizer is the best choice*

Moisture

The moisture content of saturated steam should possess a relative humidity of 97%-100%

Julian date

The number of days that have elapsed since Jan. 1st

Bioburden

The number of microorganisms on a contaminated object.

Validation

Procedures used by equipment manufacturers to obtain, record, and interpret test results required to establish that a process consistently produces a sterile product.

Verification

Procedures used by healthcare facilities to confirm that the validation undertaken by the equipment manufacturer is applicable to the specific setting.

Quality control for sterilization

Process indicator devices intended for use with individual units demonstrate that the unit has been exposed to the sterilization process.

Class 1 chemical indicator

Processing indicators used with individual packs to demonstrate that they have been exposed to the sterilization process. monitors internal and external conditions

Gravity convection

Prone to air layering which causes temperature to be uneven.

Class 3

Single-parameter indicators that react to one of the critical parameters of sterilization, and indicate exposure to a sterilization cycle at a stated value of that parameter.

Parenteral solutions

Solutions that are administrated to patients intravenously.

External solutions

Solutions that are normally given orally or by inhalation.

Conditioning (phase)

Steam enters the upper back portion of the sterilizer.

Dynamic Air Removal sterilizers

Steam sterilizers that use a vacuum pump or water ejector to remove air from the chamber. Operates at a very high temperature 270-275 degrees.

Gravity Air Displacement sterilizers

Sterilizers used in hospitals, outpatient clinics, and CS department. They create steam in the presence of air. They can also sterilize liquids.

Exhaust (phase)

The chamber drain opens and steam is removed, creates a vacuum.

Hydrologic cycle

The continual movement of water from the atmosphere to the earth and back to the atmosphere.