sterlization_asepsis

7/25/2019 sterlization_asepsis

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STERILIZATION

AND ASEPSIS


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General principals of asepsis are laid down byHungarian.

These principles were accepted afterJoseph

Lister (Father of antiseptic surgery)studied prevention of wound infection(1865-

1891).


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DEFINATIONSCLEANING - It is a process whichremovesvisible contaminationbut doesnot necessarily destroy micro organisms.

It is necessary prerequisite for effectivedisinfection or sterilization.

ASEPSIS -Term used to describe

methods which prevent contamination ofwounds and other sites, by ensuring thatonly sterile object and fluids come intocontact with them.


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ANTISEPSIS- It is the procedure orapplication of an antiseptic solutionor an

agent which inhibits the growth ofmicroorganisms, while remaining in thecontact with them.

DISINFECTION-it is a process whichreduces the number of viable microorganismsto an acceptable level but may not inactivesome viruses and bacterial spores.

STERLIZATIONSTERLIZATION-- it is the process ofdestruction or removal of all microorganismsfrom article, surface or medium, includingspores.


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Sanitizing-process that reduces microbialpopulation on object to a safe level.

Decontamination-process that removespathogenic microorganisms from an object to

make it safe to handle.


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DISINFECTION

Process that eliminates defined pathogens

Not all microbial forms

Main difference with sterilization = the

lack of

sporocidal activity

Categorized into3 levels:

High, Intermediate

Low


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RESISTANCE OF

MICROORGANISMSSterilization

High Level Disinfection

Intermediate Disinfection

Low Disinfection

Trichophyton, Cryptococcus,Candida

Pseudomonas, Staphylococcus,Salmonella

HS, C!, "S, H#, HI

Polio, Co$sac%ie, "hino

#acillus stearothermophilus

#acillus su&tilis

Clostridium sporogenes

Spores

&acterial, fungal

!yco&acteria, T# &acilli

Hydrophilic viruses

egetative fungi ' &acteria

Lipophilic viruses


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Dental instruments are classified into threecategories

critical, semi critical,ornon critical

depending on their risk of transmittinginfection and the need to sterilize them

between uses.


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SPAULDING CLASSIFICATION

Item comes in contact with Type

recommended

Critical Tissue, vascular space Sterilization

Semicritical Mucous membrane High level

disinfection

Non intact skin High level

disinfection

Noncritical Intact skin only

Intermediate or

not mucous membranes low level

disinfection


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Critical Semicritical (oncritical


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To achieve sterilization of any instrument

three definite stages are to be completed-

Pre sterilization cleaning

Sterilization process

Aseptic storage


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PRESTERILIZATION CLEANING Objective-

Removal of the organic matters, blood

and saliva which provide protective

barrier for microorganisms and preventsits destruction.

There are three methods for cleaning

-Manual-Ultrasonic

-Mechanical washing


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MANUAL CLEANING

Simplest and the cheapest method, but

time consuming and difficult to achieve.

heavy duty gloves and glasses must be

worn to protect needle stick injury andto protect eye.

Material used for manual cleaning

-Soaps-Detergents


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ULTRASONIC CLEANING

Principle- conversion of

electrical energy into vibratory

sound waves which passthrough a soap solution

containing the instrument.

Used mainly for burs, bonefiles, bone cutter, artery

forceps, saw etc.
http://www.miami-med.com/images/ultrason.jpghttp://www.miami-med.com/images/ultrason.jpg


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MECHANICAL WASHING

Principle- High-pressurejets of water with orwithout a detergent whichremoves debris frominstrument.

Small instrument likeburs, blade are not

suitable for this type ofcleaning.


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Classification of the method of

sterilization/Disinfection

A. PHYSICAL

1- Sun Light

2- Drying

3- Heat i- Dry

ii-Moist

4- Filtration

5- Gas

6- Irradiation

7- ltra soni! !leaning


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B. CHEMICAL

1" #henol Deri$ati$es % #henol& 'resol& resor!inol& !hloro(ylenol

2" )(idi*ing agents %#ot"#er+anganate& Hydrogen #ero(ide&,en*oyol

#ero(ide

3" Halogens % Iodine& !hlorine

4" ,iguanide % 'hlorhe(idine

5" uarternary .++oniu+ /'ationi!0 % 'etri+ide& ehiran

6" .l!ohols % thanol& Isoroanol"

7" .ldehydes % For+aldehyde& Glutaraldehyde

" .!ids % ,ori! a!id& a!eti! a!id

" Metalli! salts Sil$er itrate& in!e Sul8ate& in! )(ide& !ala+ine&

19" Dyes % Gentian $iolet& ro8la+ine& .!ri8la+ine

11" Furan deri$ati$es % itro 8lura*one


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HEATMost !o++on and one o8 the +ost e88e!ti$e +ethods o8 sterili*ation"

Fa!tors in8luen!ing sterili*ation :y heat are % -

i" ature o8 heat

a" Dry

:" Moist

ii";e+erature < ti+e

iii" o" o8 organis+ resent

i$"=hether organis+ has soring !aa!ity

$" ;ye o8 +aterial 8ro+ >hi!h organis+ is to :e eradi!ated


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A. DY HEAT

?illing is due to %

- Dehydration and o(idation o8 organis+s

- #rotein denaturation

- ;o(i! e88e!ts o8 ele$ated le$els o8 ele!trolytes

!. ed Heat " It is used to sterili*e +etalli! o:@e!ts :y

holding the+ in 8la+e till they are red hot" (a+le %

ino!ulating >ires& needles& 8or!es et!"

#. $lamin% " ;he arti!le is assed o$er 8la+e >ithout

allo>ing it to :e!o+e red hot" (a+le % Glass lates&

'otton >ool lays and glass slides"


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&. Hot air o'en "

It is used to sterili*e ite+s& >hi!h do not get da+aged :y high te+"su!h as la:oratory glass& 8lasAs& instru+ents >ith shar !utting

edges& ,"#" handles& #o>ders& Daen dishes& +outh +irrors"
http://www.arhinkel.com/images/sterilizer.jpg


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Tem(. ) Time" ;he sterili*ation is !o+lete i8 these t>o

8a!tors are a!hie$ed throughout the load"

;e+erature ;i+e/Min0

149o' 19

159o

' 159169o' 69

179o' 45

19o' 1

19o' 7"5


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Sterilization Control of Hot Air *'en

B ;he sores o8 non-to(igeni! strain o8 ,a!illus su:tilis and

'lostridiu+ tetani are used as a +i!ro:iologi!al test o8 dry heat"

B ,ro>neCs test stri a$aila:le that !ontain a !he+i!al indi!ator"


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+. ,LASS BEADS STEILI-E "

B;he +edia used are glass :eads& +olten +etal and salt"

B;he te+erature a!hie$ed is o8 229o

'"

B;he +ethod e+loys su:+ersion o8 s+all instru+ents su!h as

ndodonti! 8iles&artery 8or!es&s!issors and :urs& into the :eads

and are sterili*ed in 19 se!onds ro$ided they are !lean"

B. >ar+-u ti+e o8 at least 29 +inutes to ensure uni8or+

te+eratures in these sterili*ers"

B M i t h t


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B. Moist heat

'auses denaturation and !oagulation o8 roteins"

!. Pasterization ";he te+erature e+loyed is either 639' 8or 39+ins /Holder method0 or

729' 8or 15-29 se!onds /$lash method0 8ollo>ed :y !ooling ui!Aly to

139'"

Method is used 8or heat sensiti$e liuid and har+a!euti!al rodu!ts"

#. Tndallisation "

a+ed a8ter Eohn ;yndall"

(osure o8 1999' 8or 29 +in 8or 3 su!!essi$e day"

Princi(le"1ste(osure Aills all $egetati$e :a!teria < s(ores0sin!e they are

in a 8a$ora:le +ediu+& >ill ger+inate and :e 1illed on s2se3ent

occasions.


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&. A4T*CLA5E "

Stea+ is the e88e!ti$e +eans o8 sterili*ation& :e!ause o8 its

!. High enetrating !aa!ity"

#. It gi$es o8 large a+ount o8 heat to sur8a!e >ith >hi!h it !o+es in

!onta!t"


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.uto!la$es& or stea+ sterili*ers essentially !onsist o8 8ollo>ing%

i0 . !ylindri!al or re!tangular !ha+:er& >ith !aa!ities ranging 8ro+ 499 to 99liters"

ii0 =ater heating syste+ or stea+ generating syste+

iii0 Stea+ outlet and inlet $al$es

i$0 Single or dou:le doors >ith lo!Aing +e!hanis+"

$0 ;her+o+eter or te+erature gauge

$i0 #ressure gauges


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To achieve sterility, a holding time of at least 15

minutes at 121 C (250 F) or 3 minutes at

134 C (273 F) at 15 psi (100 kPa) aboveatmospheric pressure is required.

To Avoid corrosion Crawford and Oldenburg

recommended addition of ammonia to the

autoclave


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Sterilization control of the moist heat

Phsical Indicator6an alloy designed to +elt only a8ter :eingsu:@e!ted to rele$ant holding ti+e"

Chemical indicator-Stris or taes that !hange !olor on!e the!orre!t !onditions ha$e :een +et"

Biolo%ical indicator-Sores o8 Geo:a!illus stearother+ohilusare used as the test organis+s as it is toughest organis+ 8or an

auto!la$e to destroy"

Its sores reuire an e(osure o8 15 +ins at 1219! to :e destroyed"


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FILTRATION

Help to remove bacteria from heat labileliquids.

As viruses pass through ordinary filters, it

can be used to obtain bacteria freefiltrates of virus isolation.TYPES:Candle filter

Asbestos filterSintered glass filterMembrane filter


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IADIATI*7

adiation used 8or sterili*ation is o8 t>o tyes

1" Ioni*ing radiation& e"g"& -rays& ga++a rays& and high

seed ele!trons "

2" on-ioni*ing radiation& e"g" ultra$iolet light& and

in8rared light"

;hese 8or+s o8 radiation !an :e used to Aill or ina!ti$ate+i!roorganis+s"


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!. Ionizin% adiation

-rays& ga++a rays and !os+i! rays are highly lethal to D. and

other $ital !onstituents"

;hey ha$e high enetration o>er"

;here is no are!ia:le in!rease in te+erature& thus re8erred to as

cold sterilization"

'o++er!ial lants use ga++a radiation 8or sterili*ing lasti!s&

syringes& s>a:s& !atheters et!"

"


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2.Non-ionizing radiation

Two types of non-ionizing radiations are used forsterilization:-

A. Ultraviolet -

Short range UV(UVC) is consideredgermicidal UV.

At a wavelength of2537 AngstromsUV will destroymicro-organismal DNA.

Used mainly for air purification and water purificationin hospitals.

B. InfraredIt is most commonly used to purify air, such as in theoperating room. Infrared is effective, however, it hasno penetrating ability.


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ETHYLENE OXIDE

STERILIZATION (ETO)

Used almost exclusively to sterilizemedical products that cannot besteam sterilized or sensitive to

radiation.Mechanism of action:It destroysmicro-organisms by alkylation andcause denaturation of nucleic acidsof micro-organisms.

At 30 C - 60C with relativehumidity above 30 % and gas conc.between 200 and 800 mg/l for atleast 3 hours.


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Ethylene oxide is a colorless liquid with a boiling

point of 10.7 C.Highly penetrating gas with sweet ethereal smell.

Highly inflammable & in conc. greater than 3%,

highly explosive.

By mixing with inert gases such as CFC or CO2,

explosive tendency is eliminated.

Plastics, rubber & photographic equipments can be

sterilized by this method.Also used for mass sterilization of disposable items,

plastic syringes,needles,catheters,blades etc.


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Disadvantages

Lengthy cycle time

Cost

Potential hazards to patients & staff

Advantage:

Can sterilize heat or moisture sensitive medical

equipments.

Ase(tic stora%e


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Ase(tic stora%e

;he +aintenan!e o8 sterility during transortation and storage is o8

ut+ost i+ortan!e"

B Instru+ents are Aet >raed until ready 8or use "

B ;o redu!e the risA o8 !onta+ination& sterile a!As +ust :e handled as

little as ossi:le"

B Sterili*ed a!As should :e allo>ed to !ool :e8ore storage other>ise

!ondensation >ill o!!ur inside the a!As"

B ;o re$ent !onta+ination 8ro+ rodents& ants& and !o!Aroa!hes& the store

+ust :e su:@e!ted to adeuate est !ontrol "

B Materials should :e stored at least o88 the 8loor and 1 8ro+ the!eiling

B Sterile a!As +ust :e stored and issued in !orre!t date order" ;he a!As&

re8era:ly& are stored in dru+s >hi!h !an :e lo!Aed" #reset trays and

!assettes& are use8ul as& the instru+ents !an :e organi*ed as er the

ro!edure


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$4MI,ATI*7 *$ *PEATI*7 THEATE

- Fu+igation o8 the oeration theatre is a!hie$ed :y

8u+igator and otassiu+ er+anganate rea!tion te!hniue"

- ;he !he+i!al used is 49 8or+aline"

F t i fl i th f i ti f th th t


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Factors influencing the fumigation of the theatre%

!. elati'e hmidit

elati$e hu+idity lays a +a@or role in 8u+igation" .+ini+u+ o8 79 is essential" =ater used in 8u+igator

>ith 8u+igant hels to a!hie$e and +aintain hu+idity"

#. Tem(eratre

te+erature 8or e88e!ti$e 8u+igation is 399-499'"

&. $ormaldehde le'els in the Air in the o(eration

theatre

;he dose o8 8or+aline is usually de!ided :y the si*e o8

the roo+" .s a rule& 19 +l is used 8or a roo+ o8 the si*e

1999 !u:i! 8eet"


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CHEMICAL METH*DS

o a$aila:le !he+i!al solution >ill sterili*e instru+ents

i++ersed in it"

Se!ondly& there is a risA o8 rodu!ing tissue da+age i8 residual

solution is !arried o$er into the >ound >hile it is :eing used"


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Mechanism of action of chemical disinfectants%

;he +e!hanis+ o8 a!tion o8 +ost o8 the !he+i!als are

nonse!i8i! and !o+le( :ut +ost o8 the+ e88e!t

+i!roorganis+s :y one o8 the 8ollo>ing +e!hanis+s"

1" 'ell +e+:rane in@ury"

2" 'oagulation and Denaturation"

3" Intera!tions >ith 8un!tional grous o8 roteins"


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!. ALDEHYDE C*MP*47DS

a. $ormaldehde"

. :road-se!tru+ anti+i!ro:ial agent& used 8or disin8e!tion&has li+ited sori!idal a!ti$ity"

Ha*ardous su:stan!e& in8la++a:le and irritant to the eye&

sAin and resiratory tra!t"

a. ,ltaraldehde"

It is a high le$el disin8e!tant

. solution o8 2 glutaraldehyde /'ide(0&reuires i++ersion

o8 29 +inutes 8or disin8e!tion and 6 to 19 hours o8

i++ersion 8or sterili*ation"


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#.ALC*H*LS

.!t :y denatrin% 2acterial (roteins"

Solutions o8 89: ethanolare +ore e88e!ti$e than higher

!on!entrations& as the resen!e o8 >ater seeds u the

ro!ess o8 rotein denaturation as reorted :y

La>ren!e and ,lo!A /160"

Freuently used 8or sAin antisesis rior to needle

un!ture"

Iso(ro(l alcoholis re8erred as it is a :etter 8at sol$ent&

+ore :a!teri!idal and less $olatile" sed 8or disin8e!tion o8!lini!al ther+o+eter "


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&. I*D*PH* C*MP*47DS

Many studies ha$e sho>n& that& iodohor !o+ounds

are the +ost e88e!ti$e antiseti!s&" Iodine is !o+le(ed

>ith organi! sur8a!e-a!ti$e agents& su!h as&oly$inylyrrolidone /,etadine& Isodine0" ;heir a!ti$ity is

deendent on the release o8 iodine 8ro+ the !o+le("

;hese !o+ounds are e88e!ti$e against +ost :a!teria&

sores& $iruses& and 8ungi" ;hese are the +ost !o++only

used sur8a!e disin8e!tants along >ith hyo!hlorite"


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+. Bi%anide "

Most !o++only used :iguanide !o+ound is

chlorhe;idine.

It is a o>er8ul non-irritating antiseti! that disruts

:a!terial !ell +e+:rane"

It ersists on sAin 8or longer eriod o8 ti+e and that is

>hy it is e(tensi$ely used 8or surgi!al s!ru::ing&

neonatal :ath& +outh >ash and a general sAin anti-seti!"


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5.HYDROGEN PEROXIDE

Strong oxidant.

Oxidizing properties allow it to destroy

wide range of pathogens.

Biggest advantage is short cycle time.

Used in 35% to 90% concentration.


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*(eration theatre (rocedre%

Antiseptic environment:

;he rin!ile is to +ini+i*e :a!terial !onta+ination&ese!ially& in the$i!inity o8 oerating ta:lethe !on!et o8 *ones is use8ul&and +ust :e

e+loyed"

*ter and %eneral access zone- atient re!etion area and general

o88i!e"

Clean or limited access zone- the area :et>een re!etion < general

o88i!e and !orridors < sta88 roo+"

estricted access zone-8 or those roerly !lothed ersonnelengaged in oerating theatre a!ti$ities&anestheti! roo+"

Ase(tic or o(eratin% zone- the oeration theatre"


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HAND WASHING

Three types of hand washing-

Social hand washing

Clinical hand washing

Surgical hand washing


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SOCIAL HAND WASHING

Recommended following social-type contact with

clients, after going to the toilet and after covering a

cough or sneeze.A plain liquid soap is often used.


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CLINICAL HAND WASHING

A clinical hand wash is used before clinical

procedures on clients, when a client is being

managed in isolation, or in outbreak situations.

An anti-microbial soap, containing an antiseptic

agent, is used.


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SURGICAL HAND WASHING

A surgical hand wash is required before any

invasive or surgical procedure requiring the use

of sterile gloves.

An antimicrobial skin cleanser, usually

containing chlorhexidine or detergent-basedpovidone-iodine, is used.


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Surgical Scru&&ing:

he purpose is to reduce resident and transient skin flora!bacteria" to a minimum.

#roper hand scrubbing and the wearing of sterile gloves anda sterile gown provide the patient with the best possible

barrier against pathogenic bacteria in the environment and

against bacteria from the surgical team.

he following steps comprise the generally accepted method

for the surgical hand scrub-


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1" Disin8e!tion is %

a" re+o$al o8 $isi:le !onta+ination:ut does not

ne!essarily destroy +i!ro organis+s

:" redu!tion o8 nu+:er o8 $ia:le +i!roorganis+s :ut+ay not ina!ti$e so+e $iruses and :a!terial sores"

!" destru!tion or re+o$al o8 all +i!roorganis+s

in!luding sores"

d" destru!tion or re+o$al o8 all +i!roorganis+se(!luding sores"

2" Sterility assuran!e le$el /S.L0 a!!eta:le 8or !riti!al

ite+ is %

a" 4

:" 5

!" 6

d" 7


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3" =hi!h o8 the 8ollo>ing is se+i!riti!al J

a" +u!ous +e+:rane

:" inta!t sAin !" tissue sa!e

d" $as!ular sa!e

4" Mini+u+ elati$e hu+idity essential in 8u+igation is %

a" 59

:" 79

!" 9

d" 199

5" 'ide( !onsist o8

a" 2 glutaraldehyde :" 4 glutaraldehyde

!" 2 !hlorhe(idine

d" 4 !hlorhe(idine


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6" ;yndallisation is %

a" (osure o8 199 ' 8or 29 +in 8or 3 su!!essi$e day"

:" (osure o8 199 ' 8or 19 +in 8or 3 su!!essi$e day

!" (osure o8 199 ' 8or 39 +in 8or 2 su!!essi$e day d" (osure o8 199 ' 8or 19 +in 8or 2 su!!essi$e day

7" =hi!h o8 these is an aroriate sterili*ing !y!leJ

a" 121 degree !entigrade 8or 15 +in

:" 134 degree !entigrade 8or 3 +in !" 19 degree !entigrade 8or 19 +in

d" . or ,

e" all o8 these

" =hi!h o8 these is used 8or gas sterili*ation J

a" Glutaraldehyde

:" Liuid itrogen

!" thylene o(ide

d" .ll o8 these


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" =hi!h o8 these is used 8or liuid sterili*ation J

a" thylene o(ide :" Liuid itrogen

!" Glutaraldehyde

d" .ll o8 these

19" =hat >ould you use to !lean a 8le(i:le endos!oe a8ter use J

a" Sterili*ation

:" #ara!eti! a!id

!" .l!ohol

d" .uto!la$e

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