3. Cleansing
Cleansing is the removal of soil or
organic material from instruments
and equipment & may be done,
clinically, in four steps:
Rinsing the object under cold water
Applying detergent and scrubbing object
Rinsing the object under warm water
Drying the object prior to sterilization or
disinfection
4. Disinfection Disinfection is the elimination of pathogens,
except spores, from inanimate objects
Disinfectants are chemical solutions used
to clean inanimate objects
(physical processes, e.g., UV radiation,
may also be employed to effect
disinfection)
Germicides are chemicals that can be
applied to both animate (living) and
inanimate objects for the purpose of
eliminating pathogens
Antiseptics are formulated for application
to living tissue
5. The Ideal Disinfectant
Resistant to inactviation
Broadly active (killing pathogens)
Not poisonous (or otherwise harmful)
Penetrating (to pathogens)
Not damaging to non-living materials
Stable
Easy to work with
Otherwise not unpleasant
6. Disinfectant Performance…
Is dependent on Disinfectant concentrations
Is dependent on length (time) of administration
Is dependent on temperature during administration
(usual chemical reaction 2x increase in rate with each
10°C increase in temperature)
Microbe type (e.g., mycobacteria, spores, and certain
viruses can be very resistant to disinfection—in general
vegetative cells in log phase are easiest to kill)
Substrate effects (e.g., high organic content interferes
with disinfection—stainless steel bench easier to
disinfect than turd)
It is easier (and faster) to kill fewer microbes than many
microbes
7. Chemical
Antimicrobials
Agent Mechanisms of Action Comments
Surfactants Membrane Disruption;
increased penetration
Soaps; detergents
Quats (cationic
detergent)
Denature proteins;
Disrupts lipids
Antiseptic - benzalconium
chloride, Cepacol; Disinfectant
Organic acids
and bases
High/low pH Mold and Fungi inhibitors; e.g.,
benzoate of soda
Heavy Metals Denature protein Antiseptic & Disinfectant;
Silver Nitrate
Halogens Oxidizing agent
Disrupts cell membrane
Antiseptic - Iodine (Betadine)
Disinfectant - Chlorine (Chlorox)
Alcohols Denatures proteins;
Disrupts lipids
Antiseptic & Disinfectant
Ethanol and isopropyl
Phenolics Disrupts cell membrane Disinfectant
Irritating odor
Aldehydes Denature proteins Gluteraldehyde - disinfectant
(Cidex); Formaldehyde -
disinfectant
Ethylene Oxide Denaturing proteins Used in a closed chamber to
sterilize
Oxidizing agents Denature proteins Hydrogen peroxide – antiseptic;
Hydrogen peroxide – disinfectan;
Benzoyl peroxide – antiseptic
8. Walaa Abd El Latif
Sterilization
It is a controlled process that destroys
all microorganisms including bacterial
spores.
9. 12/12/2022 9:09:01 AM Walaa Abd El-Latif
Sterilization and Disinfection
of Patient Care Items
10. Walaa Abd El Latif
• The preferred methods of
sterilization are high pressure
steam/temperature (in autoclaves)
for items that can withstand high
temperature
11. Walaa Abd El Latif
•High pressure/temperature
steam sterilization
•Low temperature sterilization
13. The choice of the method
• Number and type of organisms
involved .
• Risk of infection to patients or
staff.
• Type of material of object.
14. Walaa Abd El-Latif
Critical Instruments
• Penetrate skin mucous membranes or contact
bone, the blood stream,other sterile body fluids
and body cavities
29. • Class 1 external chemical indicator
• Class 2 bowie & dick test
• Class 3 single parameter indicator
• Class 4 multiple parameter
indicator (at specific temp)
• Class 5 integrating indicator (at
specific temp)
• Class 6 emulator(cycle specific)
43. Walaa Abd El Latif
• Is it damaged or not?
• Can it be clean?
• Is it sterile?
• Is it cost effectiveness?
• Who takes the responsibility if any
thing goes wrong
46. Walaa Abd El Latif
Ethylene oxide
• Gas sterilization with ethylene oxide
using an approved gas sterilizer and
appropriate monitoring systems to
assure sterility and personnel safety.
• Monitoring: by mechanical, chemical and
biological indicators
47. Gas concentration should be 450 to 1200
mg/L,
Temperature ranges 29° to 65° C,
Humidity from 45% to 85%, and
Exposure times from two to five hours.
Walaa Abd El Latif
48. • where a chamber is flooded with a mix of
ethylene oxide and other gases which are
later aereated.
• the more recent gas diffusion method relies
on a bag that wraps the elements to be
sterilized and acts a mini-chamber in order
to minimize gas consumption and make the
process economically feasible for small
loads. (Anprolene method, bag sterilization
method or micro-dose sterilization method).
Walaa Abd El Latif
49. • Advantages
– Very effective at killing microorganisms
– Penetrates medical packaging and many plastics
– Compatible with most medical materials
– Cycle easy to control and monitor
• Disadvantages
– Potential hazard to patients and staff
– Lengthy cycle/aeration time
51. Walaa Abd El Latif
Hydrogen peroxide gas plasma
• hydrogen peroxide vapor
low-temperature gas plasma
• An electromagnetic field is created in which the
hydrogen peroxide vapor breaks apart, producing
a low-temperature plasma cloud that contains
ultraviolet light and free radicals. Following the
reaction, the activated components lose their
high energy and recombine to form oxygen and
water.
53. What is Plasma?
l
4th State of Matter - 99% of all matter in the universe
exists in the Plasma State
Solid Liquid Gas Plasma
54. The “free radical species” exist only when
the radio frequency is on. When the plasma
(radio-frequency turned off) phase ends . . .
The free
radicals and
activated
peroxide….
…Recombine to
form water vapor
(H2O) and oxygen
(O2)
THE RESULT: NO TOXIC RESIDUES
55. Disadvantages
• Cellulose (paper), linens and liquids cannot
be processed
• Sterilization chamber is small, about 3.5ft3
to 7.3ft3
• Endoscopes or medical devices restrictions
based on lumen internal diameter and length
(see manufacturer’s recommendations)
• Requires synthetic packaging
(polypropylene) and special container tray
58. Chemical Methods
The main use of chemical
disinfection is for semi
critical items (heat labile)
items where single use is
not cost effective
59. Walaa Abd El Latif
Chemical sterilization
• The use of chemicals classified as "sterilants".
• The physical properties of the item being sterilized.
It must be relatively smooth, impervious to
moisture, and be of a shape that permits all surfaces
to be exposed to the sterilant.
Effective and proper use of Chemical sterilization
is dependent on many factors including:
60. Walaa Abd El Latif
• Adequate exposure to all surfaces, both
interior and exterior. assure total immersion.
• Respect Contact time As Sterilant.
• Use of efficacious solutions: The sterilant
solution must be clean and fresh. Most sterilants come
in solutions consisting of two parts that when added
together form what is referred to as an "activated"
solution. The shelf life of activated solutions is
indicated in the instructions for commercial products.
• Rinse (both inside and out) should be
rinsed sterile water prior to use to avoid
tissue damage.
61. Walaa Abd El Latif
Chemical Sterilants (APIC, 2005
if other methods are unsuitable
• >2% glut (10 hr)
• 1.12% glut and 1.93% phenol (12 hr)
• 7.35% HP and 0.23% PA (3 hr)
• 7.5% HP (6 hr)
• Stabilized 1.0% HP and 0.08% PA(8 hr)
62. Walaa Abd El Latif
High Level Disinfection of
Exposure Time >12 m-30m, 20oC
Germicide Concentration_____
Glutaraldehyde >2.0%
Ortho-phthalaldehyde (12 m) 0.55%
Hydrogen peroxide* 7.5%
Hydrogen peroxide and peracetic acid 1.0%/0.08%
Hydrogen peroxide and peracetic acid 7.5%/0.23%
Hypochorite(free chlorine) 650-675 ppm
Glut and phenol/phenate 1.21%/1.93%___
63. Glutaraldehyde
Advantages
• Active in the presence of organic matter
• Active against bacteria, fungi, viruses, mycobacteria, and
spores ( >3 hours.)
• Compatible with lensed instruments (e.g., endoscopes),
metal, rubber, and plastic materials
Disadvantages
• Unstable
• Irritant and toxic
• Must ensure effective concentration of glutaraldehyde is
present despite repeated use and dilution (chemical test
strips)- minimum effective conc.=1.5%
Uses
• Used most commonly as a high-level disinfectant for
medical equipment such as endoscopes (20- 30 min.)
65. Hydrogen peroxide
Advantages
• Environmentally friendly because its decomposition
products are hydrogen and water
Disadvantages
• Concerns that its oxidizing properties may be harmful to
some components of endoscopes
• May cause a pseudomembrane-like enteritis and colitis if
not rinsed from endoscope
Uses
• 3% as a low-level disinfectant. Useful as a cleaning agent.
• 6% as an intermediate level disinfectant. Used for soft
contact lenses.
• Combined hydrogen peroxide with peracetic acid acts
synergistically to achieve high-level disinfection in 15
minutes.
66. Peracetic acid
Advantages
• Broad spectrum of activity to include bacteria,
fungi, mycobacteria, viruses, and spores
• Innocuous decomposition products—oxygen and
water, acetic acid, and hydrogen peroxide
• Rapid action in low concentration
• Effective in presence of organic matter
Disadvantages
• Powerful oxidizing agent and can be corrosive
• Unstable particularly when diluted
Uses
• Used for high-level disinfection or sterilization of
instruments (e.g., endoscopes)
67. Ortho-phthalaldehyde (OPA)
Advantages
• Broad spectrum of activity (high level disinfectant)
• Excellent material compatibility
• Shelf life 2 years, 75 days after opening the bottle (
use life= 14 days)
• Ready to use ; needs no activation
• Resist organic matter
Disadvantages
• Very expensive
• Irritant (eye & skin)
• Must ensure effective concentration (chemical test
strips)- minimum effective conc.=0.3%
Uses
• Used as a high-level disinfectant for medical
equipment such as endoscopes
68. Walaa Abd El Latif
• Quaternary ammonium compounds (quats)
(a)One type of commonly employed cationic
detergent disinfectants are quaternary
ammonium compounds (quats)
(b)Problems with the use of quats as disinfectants
include
(i) Their inactivation by soaps
(ii) Their inhibition by divalent cations (calcium and magnesium
ions)
(iii) Their inhibition by cotton and other porous organic substances
(iv) Their inability to kill certain species of Pseudomonas
(c"Quats are now often mixed with another agent
to overcome some of these problems and to
increase their effectiveness
69. (b)Problems with the use of quats as
disinfectants include
(i) Their inactivation by soaps
(ii) Their inhibition by divalent cations
(calcium and magnesium ions)
(iii) Their inhibition by cotton and other
porous organic substances
(iv) Their inability to kill certain species of
Pseudomonas
(c)"Quats are now often mixed with another
agent to overcome some of these problems
and to increase their effectiveness
Walaa Abd El Latif
70. Flash sterilizers
• It is a method for sterilizing unwrapped
patient-care items for immediate use
• mechanical monitors are checked and
chemical indicators used for each cycle
Walaa Abd El Latif
71. • Flash originally defined as sterilization of an
unwrapped object at 132oC for 3 min at 27-28 lbs
pressure in gravity
• Flash used for items that must be used
immediately
• Because of the potential for serious infections,
implanted surgical devices should not be flash
sterilized unless unavoidable (e.g., orthopedic
screws)
Walaa Abd El Latif
72. Unwrapped sterilization should be used
only under certain conditions:
1) thorough cleaning and drying of
instruments precedes the unwrapped
sterilization cycle;
2) mechanical monitors are checked and
chemical indicators used for each cycle;
3) items are transported aseptically to the
point of use to maintain sterility
Walaa Abd El Latif
73. Walaa Abd El Latif
• When flash sterilization is used, certain
parameters should be met: item
decontaminated; exogenous contamination
prevented; sterilizer function monitored by
mechanical, chemical, and biological
monitors
• Do not used flash sterilization for reasons of
convenience, as an alternative to purchasing
additional instrument sets, or to save time
76. Conclusions
• All sterilization processes effective in
killing spores
• Cleaning removes salts and proteins and
must precede sterilization
• Failure to clean or ensure exposure of
microorganisms to sterilant (e.g.
connectors) could affect effectiveness of
sterilization process
