ASEPTIC & ANTISEPIC TECHNIQUES

Begashaw M (MD)

DEFINITIONS Aseptic technique: prevention of microbial

contamination of tissues & sterile materials by excluding, removing or killing microorganisms

Disinfection: killing or removal of sufficient microbes to render an inanimate object safe for its intended purpose

Antiseptics: Chemicals which can be applied to living tissues to kill or inhibit the growth of microbes

CHOICE OF ANTISEPTIC Ideal antiseptic:a. spectrum of activity broadb. resistant to inactivation by organic

materialsblood & fecesc. no toxicity or allergic reaction, non –

stainingd. inexpensive

Source of infection

• patient• Staff• operation room• instruments

Route of infection

Personal contactAirborne

Preventative Measures-patient

Short hospital stay preoperatively Shower a day before surgery Treatment of any infectious site before surgery Aseptic methods Special preparations - bowel preparation for

colonic surgery use of antiseptic solution Prophylactic antibiotics

Operating Theater Staff Wear clean clothes, shoes or covers,

mask & cap Scrubbing for at least 5 min dry with sterile towel & apply 70%

alcohol Put on sterile gloves & gowns

Scrubbing & gowning

Gloving

Gowning

Gloving

Patient

Clean the operation field with antiseptic - Chlorohexidine & 2.5% Iodine for

adults- 70% alcohol for children- Povidone Iodine for all ages if available cover with sterile drapes

Draping

Operating Roomnumber of personnel reducedadequate ventilationwindows should be open to allow ingress

of fresh outside air & escape of anesthetic gases

Keep all doors closed except as needed for passage of equipment & personnel

Clean operating rooms between operations

Instruments Sterilization: - is a process by which

inanimate objects are made free of all microorganisms

Sterilize:Chemical

High-pressure steamDry heat

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Decontaminate

Clean

Dry/Cool and Store

High-Level Disinfect:

BoilSteamChemical

Aseptic Instrument Processing

Instrument Processing

Effectiveness of Methods for Processing Instruments

Method Effectiveness(kill or remove

microorganisms)

End Point

Decontamination Kills HBV and HIV and most microorganisms

10-minute soak

Cleaning (water only) Up to 50% Until visibly clean

Cleaning (water and soap)

Up to 80% Until visibly clean

Sterilization 100% High-pressure steam, dry heat, or chemical

High-Level Disinfection

95% (does not inactivate some endospores)

Boiling, steaming, or chemical for 20 min

Autoclaving

preferred method uses steam at a pressure of 750 mmHg

above atmospheric pressure & temperature of 120 degree Celcius for 15-30 mins

steam is helpful for penetration even into spores

Appropriate indicators needed

Dry heat

poor alternativesuitable for metal instrumentsuses a temperature of 170 degree

celcius for 2 hrs

Alcohols ethyl, isopropyl Acts by denaturing proteins Broad spectrum-gram-positive & gram-negative rapid action short acting moderately expensive most active against bacteria at 70% concentration Is bactericidal Also fungicidal & virucidal

Chlorhexidine

Good activity against staphylococci & streptococci

moderate activity against gram negative bacteria

persistent action-up to 6 hrsmoderately expensivenon-toxicunpleasant taste

Iodine

Lugol’s solutionBroad spectrumCheapStainsHypersensitive

Povidone iodine

Broad spectrum -spore forming organisms -both gram-positive &

gram-negativemoderately expensivesome hypersensitivity skinrapid inactivation by blood