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 broad
b. resistant to inactivation by organic
materialsblood & feces
c. no toxicity or allergic reaction, non –
staining
d. inexpensive
Source of infection
• patient
• Staff
• operation room
• instruments
Route of infection
Personal contact
 Airborne

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 Room



number of personnel reduced
adequate ventilation
windows 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
Aseptic Instrument Processing
Instrument
Processing
Sterilize:
Decontaminate
Clean
Boil
Steam
Chemical
Chemical
High-pressure steam
Dry heat
17
High-Level
Disinfect:
Dry/Cool and Store
Effectiveness of Methods for Processing Instruments
Method
Decontamination
Effectiveness
(kill or remove
microorganisms)
Kills HBV and HIV
and most
microorganisms
End Point
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 alternative
 suitable for metal instruments
 uses 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 hrs
 moderately expensive
 non-toxic
 unpleasant taste

Iodine
Lugol’s solution
 Broad spectrum
 Cheap
 Stains
 Hypersensitive

Povidone iodine
Broad spectrum -spore forming organisms
-both gram-positive &
gram-negative
 moderately expensive
 some hypersensitivity skin
 rapid inactivation by blood
