Sterilization and Disinfection Flashcards
What is Disinfection?
• Reduction or destruction of most pathogenic microorganisms on inanimate (nonliving) objects
What is a Disinfectant?
• Chemical agents that reduce microbial load on inanimate objects
What is Sterilization?
• Elimination of all microbes on an inanimate object
What is an antiseptic?
Antiseptic
• Chemical agents that reduce microbial load or inhibit growth of microbes on living/animate
objects
What is Sterility?
Sterility
• Absence of all forms of microbial life only inanimate objects
What are environments that have low level contamination?
Low level
• Reception desks
• Offices
• Walls
• Doors
What are environments that have high level contamination?
High level contamination
• Kennels/housing
• Exam tables
• Operating tables/floors
What items need critical level disinfection?
Equipment, implants entering body sterile tissue, cavity, or blood stream, surgical instrument
What items need semi-critical level of disinfection?
Equipment that comes in contact with skin
or mucous membranes without penetrating body or cavity
- Colonoscopes, flexible endoscopes, endotracheal tubes, anesthetic equipment, vaginoscope
What items need non critical disinfection?
Equipment that comes in contact with intact skin or mucous membranes but not directly associated with surgery
Laryngoscope, stethoscope, ultrasound probe, blood pressure cuffs, ECG leads, pulse oximeters, exam tables
Which of the following items should be sterilized?
A.) Colonoscopes/ Endoscopes
B.) Surgical instruments
C.) Endotracheal tubes
D.) EKG leads
B surgical instruments
(they will be entering the body.)
Which of the following items requires semi critical disinfectant?
a. ) Ultrasound Probes
b. ) Surgical Implants
c. ) Endoscopes
d. ) Catheters
c.) endoscopes
Which of the following items requires non critical disinfectant?
a. ) Laryngoscope
b. ) Suture material
c. ) Vaginoscope
d. ) Urinary catheters
a.) laryngoscope
Should be disinfected but do not require reduce microorganisms but since sterility specific handling between is not maintained during procedure patients* Should be terminally cleaned sterility isn’t required. Te r m i n a l when done for the day
Does Isopropyl Alcohol disinfect bacteria? Virus? Fungi? Spores?
yes, yes, yes, no
Does povidone- iodine disinfect bacteria? Virus? Fungi? Spores?
yes (quickly), yes, yes, yes
Does chlorhexidine gluconate disinfect bacteria? Virus? Fungi? Spores?
yes (quickly), poorly, poorly, no
Does alcohol based solutions disinfect bacteria? Virus? Fungi? Spores?
yes , sometimes, sometimes, sometimes
How does alcohol help surgeons prior to surgery?
Helpful in removing excess lipids on the skin prior to
surgery
Is alcohol used as a cold sterile agent?
no
Is alcohol bacteriostatic or bacterocidal?
Activity
• Bactericidal (bacteriostatic at lower
concentrations)
• Kills many fungi and viruses
Which antiseptic is the most effective?
Povidone-iodine (PVI)
Which antiseptic is the least effective?
Chlorhexidine Gluconate
What is Povidone- iodine? Does it leave a residue?
Activity
• Bactericidal • Fungicidal • Effective against viruses • Sporocidal (15 min contact time)
• Minimal residue
• Effectiveness decreased in presence of organic
material
What is the concentration of iodine for wound management?
0.1 to 1% solution
What is the concentration of iodine for surgical prep?
10% scrub/solution
What is the activity of chlorhexidine gluconate?
- Activity
- Bactericidal (rapid; GM + > GM-) • Minimal activity against viruses and fungi • Not sporicidal
Does chlorhexidine leave a residue? Why? Is it easily inactivated?
- Residual activity due to keratin binding
- Not inactivated by organic debris, alcohol, or soaps
What is the concentration of chlorhexidine for wound management?
• For wound management: 0.05% solution
What is the concentration of chlorhexidine for surgical prep?
For surgical prep: 4% scrub/solution
What is the activity of alcohol based solutions?
Activity
• Has superior antimicrobial activity than PVI, CHG,
or IPA alone
Which disinfectant/ antiseptic is best for spores?
Povidone- iodine
Which disinfectant/ antiseptic is best for bacteria?
alcohol based solutions
Which disinfectant/ antiseptics are best for viruses?
Isopropyl Alcohol (IPA) and Povidone-iodine (PVI)
What are the types of sterilization available?
- Steam Sterilization
- Chemical (Gas) Sterilization
- Ethylene oxide
- Plasma sterilization (hydrogen peroxide gas)
- Gas plasma
- Peracetic acid sterilization
- Ionizing radiation (gamma)
- Cold chemical sterilization
What kind of gas is used in chemical gas sterilization?
Ethylene oxide
What kind of gas is used in plasma sterilization?
hydrogen peroxide gas
How does steam sterilization work? Is it common?
Saturated steam destroys microorganisms by
coagulation and cellular protein denaturation
• Cylindrical machine
• Very common
What are the benefits of steam sterilization?
- cheap
- non toxic/ safe/ simple
- effective
- Can be used for wrapped and unwrapped items
- Quick turnaround
What are the cons of steam sterilization?
- not suitable for heat sensitive items
- potential for injury if used incorrectly/ not maintained
- Requires care and maintenance.
What is a gravity displacement sterilizer?
Gravity displacement sterilizer:
• Works on principle that air is heavier than steam • Pressurized steam goes from outer to inner chamber • Microbial death is dependent on
• Exposure time (minimum 10-30 mins based on what is being
sterilized) • Temperature (250° F- 275° F) • Pressure 15-18 PSI
• Dependable, simple design, affordable
What is a prevaccum sterilizer?
• Allows sterilization in harder to reach spaces through a vaccum mechanism • Porous items with hard to reach spaces • 3 to 4 minutes at 270°F to 275°F
What is a flash sterilizer?
• Flash sterilizer:
• Should only be used in emergencies when
no alternative is available • Uses gravity displacement sterilizer
• Metal tray • Metal nonporous items (items without
lumen)
• 3 minutes at 270° F to 275° F
• Metal items with lumen and porous items
(rubber, plastic, autoclavable power tools)
• 10 minutes at 270° F to 275° F
What are reasons for failure of a steam sterilizer?
• Inappropriate packing or loading • Poor steam quality • Vacuum failure • Inadequate temperature
What is a gas sterilizer? What are pros and cons for it?
Ethylene Oxide (EtO)
• Flammable gas
• Gas diffusion
• Lengthy time cycle
• Aeration
• Toxic
• Efficacy dependent on:
• [Gas]
• Temperature
• Humidity
• Exposure time
Pros: Sterilizes heat / moisture sensitive equipment.
Cons: Expensive, lengthy cycles, hazardous.
What is plasma sterilization? What is the pros and cons for it?
• Hydrogen Peroxide (H2O2)
• Low temp sterilization
• “Rapid”
• No drying needed
• Uses UV photons and radicals
• Kills microorganisms by oxidation
Pros: Sterilizes heat/ moisture sensitive items (# 1 option), quick turn around, no harmful emissions.
Cons: Gas cannot penetrate linen, gauze/ wood products/ some plastics. Requires specific synthetic packaging. Sterilization chamber is relatively smaller than an ETO sterilizer.
What is Ionizing Radiation? What is the pros and cons for it?
(Gamma)
• Low temperature sterilization process
• Useful for heat sensitive
equipment
• Only commercial use since it’s so
expensive
• Uses cobalt 60 gamma rays
Pros: High penetrating power, rapidity of action, low temperature, flexibility.
Cons: Expensive, dangerous, can cause breakdown of packing material or product.
What is Peracetic acid sterilization? What are the pros and cons for it?
Low temperature liquid immersion
sterilization • Good for heat sensitive items • For immediate use of items
• No long term storage
Pros: Sterilizes heat intolerant items , Rapid sterilization cycle, Low temperature, Safe
Cons: Only applicable for immersible instruments, Can be expensive, No sterile storage
What is cold sterilization?
Liquid chemicals sterilize instruments
• Noncorrosive • Effect depends on contact (immersion) time
• Disinfection = 10mins
• Sterilization = 10hrs
What are the chemicals that can be used for cold sterilization?
- Chemicals can include
- Glutaraldehyde 2%
- Ortho-phthalaldehyde (OPA) (Cidex OPA)
- Hydrogen peroxide 7.5% (Sporox II)
How should you handle instruments from cold sterile after they have been sterilzed?
• Instruments should be rinsedwith sterile water
and dried with sterile towels
What items should you sterilize with steam sterilization?
Heat-tolerant and moisture ~tolerant items (ex. surgical instruments, surgical gowns, towels)
What items should you sterilize with ethylene oxide (EtO)?
Heat-intolerant and moisture ~intolerant items (ex. plastics, endoscope, power cables, camera)
What items should you sterilize with gas plasma (H2O2)?
Heat-intolerant items (ex. most plastics; adaptor required for items with lumen)
What items should you sterilize with ionizing radiation?
Most single-use, prepackaged items (ex. suture material, punch biopsy, disposable surgical gown)
What items should you sterilize with paracetic acid?
Variety of medical and surgical instruments (ex. flexible endoscopes; special connector required for lumened endoscopes) *Only immersible instruments*
What items should you sterilize with cold chemical sterilization?
Items containing metal, rubber or plastic and/or lensed instruments (endoscopes, cystoscopes, bronchoscopes, arthroscopes)
What are the components needed to be wrapped in surgical packs? How should they be wrapped?
Components needed for surgery in one
sterile pack
• Gown + towel • Instruments + gauze • Miscellaneous items
• Wrapping material depends on method
of sterilization
When are paper bags used for surgical equipment, and what are the pros and cons of this kind of wrap?
- Paper bags
- Small light, non- sharp items
- Cotton balls • Gauze
Pros: Cheap, easily obtained
Cons: easily perforated when wet, items cant be visualized, heavy items can break through
What linen materials are used for wrapping materials?
- Linen material
- Usually cotton blend (muslin or linen) • Synthetic material
What are laminated sleaves/ pouches/ packs made of? What are the pros and cons of these packs?
• Laminated sleeves/packs/pouches
• Combination of transparent heat stable
plastic film laminated to treated paper
Pros: Cheap/ easily obtained, pre cut, several small items can fit at once, instruments can be identified.
Cons: Easily perforated when wet, heavy items can break through
What is the purpose of instrument containers? What are they made of?
- Instrument containers
- Aluminum and stainless steel
- Store a wide range of surgical instruments
What is the procedure for preparing instruments for surgical pack wrapping?
- Cleaning and sonicating instruments
- Pre clean rinse
- Instrument soak
- Cleaning
- Manually • Ultrasonic cleaning equipment
- Post clean rinse
- Instrument drying
What is the procedure for wrapping a surgical pack
Varies based on the pack but should:
- Place and organize instruments
- Add drape and gauze
- Add sterile indicator
- Wrap (2x)
- Secure with autoclave tape
- Sign and initial
What different sterilization indicators can be used? Why do we use them?
• Monitors effectiveness of the sterilization process • Chemical indicators:
• Chemical change occurs in response to heat, pressure and/or
humidity but NOT exposure time
- Does not confirm sterility
- Biological indicators:
- Only means of ensuring sterility following sterilization
- Sterility is assessed using bacteria maintained in a broth or on a strip
What is important to remember about wrapping surgical packs?
All surgical items should be wrapped so they can be easily unwrapped without breaking sterile technique
What is the purpose of folded towels in packs?
- Used to dry hands
- Used as drapes
What are important tips to remember when making packs?
- Incomplete surgical packs may drive you crazy!
- What you wrap your pack in is very important!
- How you wrap a pack can affect whether it can be opened aseptically
- Use autoclave tape…not masking tape
- When wrapping pouches, ensure handles face the opening for the vet
- Multipart instruments should be double wrapped
- How you place an instrument will affect whether it is sterile
- Correct sealing of bags is essential
- Do not reuse single use laminated pouches, bags, and wraps
- Keep in mind where you label and with what
