Basics of Sterilization

David R. Woodard, MSc, CIC

Dr. Earle Spaulding

“You can clean without disinfecting, but you cannot disinfect without cleaning”

Decontamination Area

The location designated for the collection, retention, & cleaning of soiled instruments

Physically separated from all other areas to decrease risk of cross infection

Air from decontam area is exhausted to the outside and not recirculated

Types of Cleaning

Decontamination Process that removes as many

microorganisms as possible by physical, mechanical or chemical means

Also known as cleaning Utilizes water, detergent and enzyme

soln Enzyme separates blood, bone and tissue

from instruments

Types of Cleaning

Disinfection Immediate state between physical

cleaning & sterilization Uses thermal processes or chemical

germicides

Manual Cleaning of Instruments

Cleaned under water with nonabrasive neutral PH detergent Low sudsing and & does not leave

residue Special attention given to hard to

clean areas Items with lumens are cleaned with

brushes and flushed with water

Inspection of Instruments

Cleanliness, & absence of corrosive substances

Free motion of hinged instruments-absence of stiffness

Proper alignment of jaws & teeth Proper tension with closed ratchets Sharpness of blades, trocars, absence of

burrs, gouges Screws and pins are clean

Inspection Con’t

General integrity-absence of cracks, dents, chipping, worn areas

Intact insulation sheathing, absence of tears

Items composed of more than one part are complete & parts fit together securely

Powered surgical instruments appropriately lubricated & tested for proper functioning

Preparation of Instruments

Remove gross soil at point of use Jaws, blades, serrations, box locks commonly

retain high levels of bioburden Remove blood/tissue with water & sponge

↓number of organisms Reduces nutrient material that promotes bacterial growth Minimizes potential for environmental contamination Removes substances that damage the instruments

Organization of Instruments

Maximize surface area of instruments Place instruments in a mesh bottom tray

to allow for full exposure of cleaning mechanism

Open jointed instruments at box locks Disassemble instruments composed of

more than one part Separate delicate scissors & microsurgical

instruments from heavier instruments to avoid damage

Assembly of Items for Sterilization

All hinged instruments must be opened & secured with stringers in a wire mesh basket

The weight of an instrument set should be evenly distributed to avoid collection of moisture during sterilization

A towel may be positioned in the tray to facilitate revaporization of condensate

Delicate instruments require tip guards/foam

Count sheet in every tray

Packaging Materials

Items must be packages in a manner that maintains their sterility

Appropriate packaging material Allows effective sterilant penetration Must contain the sterility of the

processed items Must allow aseptic presentation of

contents

Paper-Plastic Package System

Allows for proper sealing to secure contents

Remove as much air as possible to facilitate effective sterilization

Double peel packages should be sequentially sized & sealed to allow fro proper fit of inner pouch

Paper sides of both packages are positioned together to allow adequate penetration of the sterilant

Rigid Sterilization Containers

Reduce cost and management of waste

Perforations in the lid and bottom are covered with disposable bacterial filters Filters allow sterilant to penetrate

Tamperproof locks & ID labels Need to follow recommended weight,

density, sterilization cycles & times & loading practices

Storage of Packaging Materials

Room temperature Humidity 35% to 70%

High humidity Packaging may become over hydrated which

can affect integrity of adhesives & seals of peel packages

Low humidity Dehydration Brittle and easily tear

High Level Disinfection

Uncontrolled process Efficacy is directly affected by the

cleanliness of the device, preparation of the device, the level of the active ingredient, temperature of solution and the exposure time Testing the solution according to

directions

Chemical Disinfection(Cidex OPA)

High Level Disinfection Performed by submersing an item in

a covered basin of germicidal solution for a designated length of time to achieve the desired level of microbial kill

May eliminate many or all pathogenic microorganisms

Will not kill spores

Disinfecting Issues

Product must be: Tested once each day of use or each

time used when not used daily. Changed as manufacturer requires Test strips tested for accuracy (high/low)

at time of introduction to use Test strips expire! Temperature sensitive

Disinfection

Improper cleaning and organic debris are among many factors that have been known to nullify or limit the efficacy of this process.

Washer Sterilizers

Wash, rinse, & use gravity steam sterilization

High temps & steam leads to total destruction but they should not be considered ready or safe for patient use

Must clean & remove bioburden Tissue or debris not removed during wash

cycle may be baked on during sterilization cycle

Advantages of Washer Sterilizer

↑ penetration capability Exposure of higher temps to all surface areas Greatest incidence of microbial lethality Automatic time-released lubrication cycle

Sterilization

The process of killing all forms of microbial life

Sterilization Indicators

Class I – External, time, temp, pressure indicator, says item went through autoclave (tape, peel packs)

Class II – Bowie Dick, checks for air removal Class III – Internal, time & temp, rarely used

today Class IV – Internal, reacts to two or more

parameters, rarely used today Class V – Integrators, melted chemical pellet,

reacts to all parameters, all steam cycles Class VI – Emulating indicators, cycle specific Biological – gold standard, shows kill of

organisms

PASS THRU WINDOWAUTO WASHER

WORK TABLE

WELCOMETO

DECONTAM

WASHER

WIN

DO

W

WELCOME TO

STERILE PROCESSING

AUTOCLAVE

READY FOR

STERILIZATION

WORK

TABLES

COUNT SHEETS

INC

UB

ATO

R

OBSOLETEEQUIP / INST

WORK AREA

Steam SterilizationMoist Heat

Most economical & efficient Rapid processing time allows

frequent availability Items must be able to tolerate high

temps & moisture Works with time, temperature &

moisture

Steam SterilizationTime, Temperature, Moisture

Steam circulates within the jacket space surrounding chamber

Steam enters the chamber & displaces all the air Air and steam do not mix

As pressure increases, saturated steam contacts all surfaces , penetrates packages, & forces air out through a drain at the bottom of sterilizer

Sterilization is initiated once all air is removed High temp of saturated steam causes microbial

destruction Proper loading is crucial to allow the steam to

freely circulate

Steam Sterilization Con’t

Temperature affects the time of exposure in that the higher the temperature, the less exposure time is required. As pressure ↑ in a closed chamber, so does the

temperature If these parameters are not

represented in a cycle, sterilization will not occur

Cycle Phases

Conditioning Air removal

Exposure Load is heated to sterilization temp

Exhaust Bottom drain opens and steam is exhaused

Drying Dry heat revaporizes existing moisture &

removes from the load

Proper Loading & Unloading

Proper Loading Prevents formation of air pockets &

obstructions to the circulation of steam Proper Unloading

Hot packages are allowed to cool before being handled

Moisture will form upon contact and cause contamination

Called strike through Do not place hot items on cool surfaces

Sterilization Process Monitors

Chemical Monitors (Indicators) Monitor one or more process parameters of a

sterilization cycle Detects failures in packaging, loading or sterilizer

function Consist of a sensitive chemical or ink dye that

develops a visual change after the exposure to certain physical process conditions (temp & humidity)

Placed on the outside of every package Need to be examined after sterilization & before

use

Chemical Monitors Con’t

Internal monitors placed in the area of greatest challenge within the package

Visible once package is opened Both internal l& external indicators reflect

exposure of an item to one or more sterilization parameters

Do not guarantee sterility If questionable, item is not considered

sterile

Biologic Monitors

Standardized preparation of known microorganisms highly resistant to a specific mode of sterilization.

Their purpose is to reveal evidence of the efficacy of a sterilization cycle by utilizing a high number or resistant spores to challenge the function of the sterilizer.

Most reliable monitors

Biologic Monitors Con’t

After cycle is complete put in incubator to observe microbial growth

Negative biologic monitors contain no growth & indicates that conditions necessary for sterilization & microbial kill were met

If growth detected: Notify supervisor immediately Further test & evaluate to determine viability of

organisms & efficacy of the cycle

Biologic Monitors Con’t

Bacillus stearothermophilus Steam sterilization

Bacillus subtilis Gas sterilization

Impregnated on paper strips or capsules and placed within the chamber Special test packs or Wrapped in items

Biologic Monitors Con’t

A control biologic monitor, which has the same lot number, as the test and has not bee exposed to a cycle is also incubated and examined for growth

Routine Biologic Monitoring

Frequency of Use: During installation of sterilizer or after

major repairs Daily in steam autoclaves Gas-with each load Any load with implants

Routine Biologic Monitoring

Placement: Steam

In loaded chamber over drain or coolest part of sterilizer

Gas In the middle of the loaded chamber

Incubation: Usually 48 hours 1 hr incubation monitors available for gravity

displacement steam sterilizers

Bowie Dick Test

Daily air removal test Insures proper function of the

vaccuum and detects any air leaks Monitor is placed on the bottom rack

over the drain before the first load Satisfactory test occurs when there is

a uniform color change

Bowie Dick Test

Biological Indicators

Following the autoclave cycle, the BI is placed in an incubator; also a control

Length varies with the product; rapid readout 1-3 hours, or 24 hours

Positive test = sterilization process has failed due to improperly processed load, failure to meet temperature or exposure parameters, mechanical problems, etc.

Yellow = pusFAIL

Purple = bugskilled, PASS

Ethylene Oxide Sterilization

Used to sterilize heat-labile and/or moisture-sensitive items

Toxic & flammable Lengthly processing /aeration time High cost Environmental concerns

ETO SterilizationGas

Colorless, noncorrosive, highly penetrative

For items that are sensitive to high concentrations of moisture and/or heat

Appropriate conditions of time, (105-300 min) temp, (low) EO concentration, relative humidity (45%-74%)

Appropriate aeration is required to remove residual EO

EO Aeration

Continuous currents warm filtered air 12 hrs = 120 degrees 8 hrs = 140 degrees

Hydrogen Peroxide Gas Plasma Sterilization

Sterrad Rapidly destroys microorganisms utilizing

low temperatures without toxic residue Used for heat and moisture sensitive items Uses radio frequency energy to vaporize

hydrogen peroxide Takes approximately one hour For narrow lumens that are longer than

12” or narrower than ¼ “ , a special adaptor is needed

Chemical SterilizationThe Steris

Used on items that are heat sensitive Delicate instruments, scopes, cameras

Uses a lower temperature & shorter cycles

Peracetic Acid

SterisPeracetic Acid Sterilization

“Just In Time” Peracetic Acid Acetic acid, hydrogen peroxide, water Adversely reacts with protein & enzymes

of microorganisms penetrating cell wall & causing destruction

Sterilant mixes with water, which reduces concentration of the acid

Takes about 30 minutes Works by time, temp and concentration

Immediate Use Sterilization

Only used in special situations Use open , perforated mesh bottom

trays Trays with lids may impede air removal

& steam penetration Gravity displacement method Disassemble all instruments Flush lumens with distilled water

Flash Sterilization Con’t

Parameters Simple instruments

Gravity displacement 270 degrees for 3 minutes

Complex instruments Gravity displacement 270 degrees for 10

minutes

Flash Sterilization Con’t

Several like instruments can be sterilized together

More than 1 instrument tray requires 10 min

Lumens must be flushed with water Trays with rubber or cloth run for 10

min

Flash LogThe same tracking process as for items put up in CS.Review daily for complianceReport to ICC and department of surgery at regular intervalsUse to support additional sets

“We need to flash the hyster tray because we only have one”

Issues

Documentation Pt name/MR # Items in load User initials

Recalls Policies and Procedures

Sterility

The loss of sterility is related to an event, not to time. Germs don’t have a calendar that says –

“ok it 28 days, lets contaminate the Kockers”

Events – Dampness Loss of package integrity Dirt

Why Expiration Dates?

Why are their expiration dates if we believe that sterility is event related? Commercially prepared products are

tested for sterility at time intervals (the guarantee).

At some point in time, they stop testing, and that’s as long as the guarantee can be made.

Scopes the bane of our existence

Which scope was used on which patient

Cross contamination Biological Tissue

Disinfection Storage

Problems in Ambulatory Infection

Control Many well-publicized outbreaks in

ambulatory centers Two main causes:

Unsafe injection practicesImproper cleaning, disinfection,

sterilization of instruments, endoscopes Nevada & Nebraska outbreaks resulted in

criminal charges and license revocations

CMS IC RequirementsMust list national guidelines being usedFollow them!

CDC/HICPAC Guidelines:

Guideline for Isolation Precautions (CDC/HICPAC)

Hand hygiene (CDC/HICPAC)

Disinfection and Sterilization in Healthcare Facilities (CDC/HICPAC) Environmental Infection Control in Healthcare Facilities (CDC/HICPAC)

Perioperative Standards and Recommended Practices (AORN)

Guidelines issued by a specialty surgical society / organization (List)

Please specify (please print and limit to the space provided):

CMS IC Requirements NOTE! If the ASC cannot document that it has designated a qualified professional with training (not necessarily certification) in infection control to direct its infection control program, a deficiency related to 42 CFR 416.51(b)(1) must be cited.

Lack of a designated professional responsible for infection control should be considered for citation of a condition-level deficiency related to 42 CFR 416.51.

CMS IC Requirements

Prefilled syringes- single patient use IV bags- single patient use, spike just

prior to use IV tubing and connectors- single

patient use Sharps safety devices, proper disposal

The Great Clave Experiment…

15 clave ports from 15 different hospital units were randomly selected and cultured. 11 of the 15 grew Coag-Neg Staph or Staph Epidermidis plus lots of other nasty stuff. Four cultures grew nothing…

(but 2 of them were from brand new IV sets…)

Scope Processing

Written policy and procedure for: Immediate post-procedure cleaning,

leak testing, what to do if it fails Thorough cleaning, brushing channels Proper connections for AERs High-level disinfection/sterilization Manufacturers’ written instructions