Sterilization and disinfection of urological instruments

1. Sterilization and Disinfection
Presenter :
Dr. Gaurav Sharma
1st yr DrNB urology resident
Pushpanjali Hospital
Agra

2. • Cleaning : removal of visible soiling from objects using water with
detergents
• Decontamination : process of removing pathogenic microorganisms
from objects so they are safe to handle, use or discard
• Disinfection : eliminating all pathogenic microorganisms except
bacterial spores.
• Sterilization : an article, surface or medium is freed of all living
microorganisms either in the vegetative or spore state.

3. US FDA definition of sterilized device
• device that has been processed in a system that delivers a
sterility assurance level of 10–6, which is a one in a million
chance of a non-sterile occurrence.
• High-level disinfection does not achieve this level of
sterility

4. • Chemical sterilants- kills all micro organisms as well as spores
• High-level disinfectants - kill all microorganisms, except large numbers of
bacterial spores
• work at similar concentrations but with shorter exposure periods (e.g., 20
min for 2% glutaraldehyde),
• Intermediate-level disinfectants- might destroy mycobacteria, vegetative
bacteria, most viruses, and most fungi but do not necessarily kill bacterial
spores.
• Low-level disinfectants - kill most vegetative bacteria, some fungi, and some
viruses in a shorter period of time (<10 min).

5. Antiseptic
• Antiseptics are applied to living
tissue and skin
• prevent or arrest the growth or
action of microorganisms by
inhibiting their activity or by
destroying them
Disinfectant
• antimicrobials applied only to
inanimate objects

6. Spaulding Classification:
• Critical items: enter the body cavity, vascular system, or non intact mucous
membranes.
• Includes most surgical instruments
• should be sterile.
• preferred method of sterilization -autoclave or low temperature
sterilization
• Semi critical items: directly or indirectly come in contact with intact mucous
membrane or non intact skin.
• high level disinfection
• preferably sterilize whenever possible e.g., cystoscope.
• Noncritical items: come in contact with skin but not mucous membrane
• low level disinfection by cleaning
• BP cuffs or crutches

7. Methods of sterilization :
High temp.
• Hot air oven
• Autoclave
Low temp.
• Hydrogen Peroxide Gas Plasma Sterilization
• Ethylene Oxide Sterilization
• Chemical Agents Used as Disinfectants/Sterilants
• Alcohol (Ethyl Alcohol, Isopropyl Alcohol, 60–90% Solutions in
Water)
• Aldehyde Group of Chemical Disinfectants [Glutaraldehyde
(2.4%) and Formaldehyde]
• Peracetic acid
• Iodophores

8. Hot air oven
• Convection oven with stainless steel chamber and perforated shelving is
ideal
• a simple oven with a thermometer can be used for dry heat sterilization.
• Metal sheaths of cystoscope and sharp instruments can be sterilized by
hot air oven.
• needs more time for sterilization compared to autoclave

9. Autoclave
• MOA : irreversible coagulation and denaturation of enzymes and
structural protein
• Temperature 121°C, with pressure of 106 kpa (15 lb/inch2) for 30
minute
• Adv: Nontoxic, easy to control and monitoring, rapidly
microbicidal, least affected by organic/inorganic soils, rapid cycle
time.
• Disadv: Heat-sensitive instruments cannot be sterilized
• repeated sterilization with this technique will lead to loss of
sharpness of cutting instruments.

12. Hydrogen Peroxide Gas Plasma Sterilization (Sterrad) 
•1.8 mL of 58% hydrogen peroxide vaporized in a sterilization
chamber
•vapor is converted into plasma (highly charged particles and free
radicals) through the use of radiofrequency (RF) energy
•sterilize instruments in about 1 hour without producing toxic
residues or emissions .
•H2O and O2 end products

13. SterradTM

14. • MOA : Destroys by combined use of hydrogen peroxide gas
and generation of free radicals (hydroxyl and hydroperoxyl
free radicals)
• Adv : Nontoxic, cycle time from 35 to 60 minutes, simple to
operate, most of the instruments can be sterilized.
• Disadv : Linens cannot be processed. It requires special unit
for packaging. Plastics and corrosion sensitive metal cannot
be processed.

15. Uses:
• Compatible with most (>95%) medical devices and materials (laparoscopes,
nephroscopes, semirigid and flexible ureteroscopes, cables, etc.).
• used to sterilize almost everything such as rigid telescopes, flexible
fiberscopes, and semi-rigid fiberscopes, video cameras, fiber- and fluid light
cables, surgical instruments, insulated (forceps, scissors, etc.), surgical
instruments, non insulated (forceps, scissors, etc.), cords, etc

16. Ethylene Oxide Sterilization
• Ethylene oxide (EO or ETO) gas is commonly used to sterilize objects
sensitive to temperatures greater than 60°C such as plastics,
laparoscopes, endoscopic lens, wires, and electric items
• generally carried out between 30°C and 60°C with relative humidity
above 30% and a gas concentration between 200 and 800 mg/L for at
least 3 hours
• penetrates well, moving through paper, cloth, and some plastic films and
is highly effective.
• can kill all known viruses, bacteria, and fungi, including bacterial spores

17. ETO sterilizer

18. • MOA : Alkylation of protein, DNA, and RNA
• Adv : Penetrates packaging materials, device lumens, user friendly, and
compatible with most medical devices
• Disadv : Requires time for preparation, ETO is toxic, carcinogen, and
flammable, lengthy cycle/aeration time
• Uses : Critical items (and sometimes semicritical items) that are moisture or
heat sensitive
• eg. Fibreoptic endoscopes, surgical telescopes, laparoscope, plastic
instruments (e.g., specula and syringes), anesthesia masks and circuits,
rubber and plastic tubing (e.g., catheters), respirators, and inhalation
therapy supplies.
• 40cm length,1mm dia-Effective
• 125cm L, 3mm dia –Not effective

19. Chemical Agents Used as
Disinfectants/Sterilants
Alcohol (Ethyl Alcohol, Isopropyl
Alcohol, 60–90% Solutions in Water)
• MOA: Denaturation of proteins
• Adv: Easily available, no activation time
• Disad : Lacks sporicidal action, damages
the shellac mountings of lensed
instruments, tends to swell and harden
rubber and plastic, and flammable.
• Uses: To disinfect external surfaces of
equipment (e.g., stethoscopes,
ventilators, manual ventilation bags), and
ultrasound instruments
Aldehyde Group of Chemical Disinfectants
[Glutaraldehyde (2.4%) and Formaldehyde]
• MOA : Alkylation of sulfhydryl enzymes and
amino acid (AA)
• Adv : Relatively inexpensive and compatible
with most of the instruments
• Disad : pungent, and irritating odor. Relatively
slow mycobactericidal activity. Coagulates blood
and fixes tissue to surfaces. Allergic contact
dermatitis.
• Uses: Formaldehyde preparation of viral
vaccines, to preserve specimens, and to
disinfect fluid pathways in dialysis machines.

20. Glutaraldehyde (Cidex) Sterilization
• High level disinfectant for endoscopes, laparoscopic trocars
• 2.45% w/v glutaraldehyde with activator
• available in a 1 L, 2 L, and 5 L package.
• Water from wet items will dilute the chemical solution, thereby reducing
its effectiveness
• use life is 14 days.

21. Important points :
• Prepare the solution by following the manufacturer’s instructions.
• put it in a clean container with a lid .
• Always mark the container with the date the solution was prepared and
the date it expires (usually 2 weeks).
• Decontaminate, clean and thoroughly dry all instruments to be sterilized
• Open all hinged instruments and other items and disassemble those with
sliding or multiple parts.
• Instrument should be completely submerged in solution.

22. • For sterilization, 10–12 hours of soakage is required
• Before using , instruments cleaned by sterile water, as cidex is toxic to
endothelium
• commonly used for rapid sterilization. Instruments are soaked only for
20–30 min. This achieves only disinfection.
• Telescopes if soaked for 12 hours may cause damage of cement resulting
in fogging of telescopes
• Even other instrument’s life may be reduced with long soakage.

24. Formaldehyde
• prevalent in surgical operation theaters in India,
• available in the form of paraformaldehyde polymer of formaldehyde, as
tablets of 1 g each.
• inadequate information regarding its efficacy
• No standardization about number of tablets, duration of exposure, how
many times the door of box is opened, when to change the tablets etc.
• discarded from almost all countries.

25. Ortho phthalaldehyde (OPA)
• MOA: Interacts with AA, proteins to cause their breakdown.
• Adv: Fast-acting high-level disinfectant.
• No activation required.
• Non irritant.
• Excellent materials compatibility.
• Does not coagulate blood or fix tissues to surfaces.
• High stability over a wide pH range.
• Disadv: Stains skin, mucous membranes, clothing, and
environmental surfaces.
• Repeated exposure may result in hypersensitivity in some
patients with bladder cancer.
• More expensive than cidex
• Eye irritation
• Slow sporicidal activity

26. • Uses: High level disinfectant for endoscopes, anesthesia equipment,
laparoscopic trocars
• Pack size: 1 L and 5 L.
• The shelf-life –
• 2 years for unopened bottle
• 75 days for open bottle
• Test strips are used to determine minimum effective concentration
(MEC).
• OPA does not require activator.

27. Per Acetic Acid
• increasingly used nowadays in place of glutaraldehyde.
• PerasafeTM is 0.2 % peracetic acid.
• MOA : Oxidizing agent which denatures protein, disrupts cell wall, and oxidizes
sulfhydryl group
• 5 minute disinfection cycle and a 10 minute sterilization cycle.
• 80 g in 5 L is used
• life of the solution is 24 hours.
• In automated endoscope reprocessors, it can be used for 20 reprocesses

28. • Adv: Rapid sterilization cycle time.
• Low temperature (50–55°C) sterilization.
• Environmental friendly by-products (acetic acid, O2, and H2O). It is 100%
biodegradabe.
• Disadv: Potential material incompatibility (e.g., aluminum anodized coating
becomes dull)
• Used for immersible instruments only.
• small number of instruments can be processed in a cycle.
• Serious eye and skin damage (concentrated solution) with contact.
• Point-of-use system, no sterile storage.
• Automated machine used to sterilize medical instruments (laparoscopes and
endoscopes), surgical instruments, and dental instruments.

30. Glutaraldehyde O-phthalaldehyde Peracetic
1. Level of
disinfection
HLD HLD HLD/Sterilant
2. Contact time for
HLD
Sterilization
20-45 min.
10 hr.
10-12 min.
24hr.
5 min.
10 min.
3. Specialized
ventilation
Required Required Not required
4.Toxic to
environment
+++ + -
5.Neutralization 25g/g Glycine 25g/g Glycine --

31. Iodophors
• MOA : Disruption of protein and nucleic acid structure and synthesis by
iodine
• Adv: easily available, inexpensive
• Disadv: High level disinfectant, adversely affect silicone tubing , cannot
be used as hard surface disinfectants due to concentration differences.
• Uses: as antiseptics, disinfecting blood culture bottles, thermometers and
endoscopes.

32. STEPS OF STERILIZATION AND PROCESSING OF SURGICAL INSTRUMENTS
• Pre cleaning
• Disassembly
• Cleaning
• Packaging
• Sterilization process
• Storage: shelf life according to porosity of storage
• Monitoring :biological /chemical monitors

33. • Precleaning: removing of gross soil (blood and sputum)
at point of use.
• If not possible, then submerge instruments in
detergent/enzymatic cleaner to prevent organic
matter from drying.
• Disassembly: Facilitates the access of cleaning agent to
the device surfaces.

34. • Cleaning: removal of foreign material (e.g., soil and organic material) from
objects
• accomplished using water with detergents or enzymatic products
• Cleaning is done either manually or mechanically.
• Manual cleaning - two essential components are friction and
fluidics. Friction (e.g., rubbing/scrubbing the soiled area with a
brush) and fluidics (i.e., fluids under pressure)
• Mechanical or automatic cleaners - ultrasonic cleaners, washer-
decontaminators, washer- disinfectors, and washer-sterilizers.

35. Manual cleaning by friction
Manual cleaning by fluidics

36. Mechanical cleaner

37. Drying using air gun

38. • Packaging : Once cleaned and dried,
instruments requiring sterilization
must be wrapped or placed in rigid
containers and should be arranged in
instrument trays/baskets. Options
include peel open pouches, roll
stock/reels, and sterilization wraps.

39. Packaged instruments
before sterilization

40. • Loading: In perforated trays for free circulation of sterilizing steam/agent
to ensure proper exposure of all instruments
• Sterilization process: According to the type of instruments/devices to be
sterilized
• Storage: Shelf-life varies according to the porosity of the packaging
material and storage conditions.
• Heat-sealed , plastic peel-down pouches in polyethylene overwrap
have been reported to be sterile for as long as 9 months after
sterilization,
• whereas the double-layer muslin covering can keep the contents
sterile for a period of 1 month

41. • Monitoring: by combination of mechanical, chemical, and biological indicators to
evaluate the sterilizing conditions and indirectly the microbiological status of the
processed items.
• Biological indicators – Ideal monitors of the sterilization process
• measure the sterilization process directly by using the most resistant
microorganisms (i.e., Bacillus spores).
• Chemical monitors are either heat- or chemical-sensitive inks that change
color when one or more sterilization parameters (e.g., steam-time,
temperature; ETO-time) are present
• should be preferably placed on the inside of the pack too.

42. Rigid endoscopic instruments-
• include the cystoscope sheaths, integrated cystoscopes, working
elements, rigid nephroscopes, semirigid ureteroscopes and rigid
telescopes.
• are semicritical items by Spaulding classification.
• Disassembling, precleaning and cleaning of instruments are done.
Instruments are also evaluated at this point to check for any damage.
• Hard water should be avoided while cleaning , may lead to deposition of
crystals and alter efficacy of disinfectants

43. Rigid telescopes:
• delicate instrument and need gentle handing.
• Newer telescopes can be autoclaved (although they should be
autoclaved only if instrument specifications mention that they
are autoclavable).
• Previously - not autoclavable because their metal and glass
items would get expanded and contracted unequally on heating
and cooling respectively, thus causing damage to the rod lens
system.
• can also be sterilized by ETO or plasma sterilization

44. Sheaths:
• These are inspected for bends, rough edges, all movable parts
and valves are inspected and if necessary lubricated with
instrument milk.
• sterilized by steam, autoclaving, ETO or plasma .
• can also be disinfected with glutaraldehyde.

45. Single piece endoscopes:
• These include nephroscopes, semirigid ureteroscopes and integrated
cystoscopes.
• sterilized by ETO and plasma sterilization .
• can also be autoclaved but manufacturer’s instructions should be
followed
TUR instruments:
• Working element of transurethral resection (TUR) and optical
urethrotomes can be sterilized by autoclaving and plasma sterilization.
• TUR loops - by plasma sterilization and ETO.

46. Flexible endoscopic instruments:
• include flexible ureterorenoscope and flexible
nephroscope/cystoscope.
• semicritical category of Spaulding classification.
• The precleaning starts at the site of use. The external surface is
wiped clean with soft cloth immersed in detergent solution.
• Through the working channel the detergent solution is rinsed for 30
s, water for 10 s and air for another 10 s. All detachable parts are
dismantled.

47. • The leakage tester is attached to the venting connector of the scope and the
hand pump is used to achieve the desired pressure.
• Entire scope immersed in water and flexible parts are deflected and water
observed for persistent air bubbles from any particular point.
• working channels are cleaned with manufacturer provided brushes. Rinse the
endoscope and then it is dried and packed for sterilization.
• sterilization can be done with ETO or plasma sterilization.
• If sterilization is not possible then high level disinfection with glutaraldehyde.

48. Endoscopic accessories:
• Camera, baskets, cautery cables and other electrical cords
• can be sterilized by ETO or plasma vaporization.
• Some cameras can be disinfected with glutaraldehyde
• Laser fiber
• sterilized with ETO, plasma vaporization
• high-level disinfection can be achieved by glutaraldehyde

49. • Dilators and access sheaths
• Fascial dilators, serial ureteric dilators, balloon dilators, Amplaz
dilators and ureteric access sheaths are one-time use items
• however, in many countries reused after sterilization.
• sterilized by ETO or plasma sterilization (should not be autoclaved)
• Alken metal dilators can be autoclaved, or sterilized by ETO or plasma
sterilization.
• Percutaneous nephrolithotomy (PCNL) forceps and the semirigid
ureteroscopy forceps (Biflange and triflange) and Energy probes
(pneumatic or ultrasonic) can be sterilized by autoclaving or ETO or
plasma sterilization.

51. Thank You