Lecture 5: Antiseptics, Sterilization Methods, & Care of Surgical Equipment (Quiz) Flashcards
What are common antiseptics used in vet med
- 70% isopropyl alcohol
- 2 - 4% chlorhexidine gluconate
- 10% povidone-iodine
Describe alcohol used in vet med
- Only effective against vegetative bacteria
- Poor efficacy against spores, fungi, & viruses
- Higher & more rapid kill rate than chlorhexidine & betadine
- MOA: Denatures proteins
- Mild de-fatting/greasing effect (used to improve contact in ultrasound)
- Inactivated by most organic debris
- No residual effect after evaporation
- Toxic to the cornea
Describe alcohol when talking about scrubbing
- The optimal concentration is 60 - 90%
- Looses efficacy if diluted < 50%
- Most common rinse but lowers body temp in small animals
Describe isopropyl alcohol
- Higher more rapid kill than chlorhexidine
- Third best povidone-iodine
- Can potentiate antimicrobial efficacy of providone - iodine (releases iodine)
Elaborate on chlorhexidine gluconate
- Rapid onset
- Persistent effect
- Binds to protein of stratum corneum
- Residue kills bacteria exiting sebaceous glands, sweat glands, & hair follicles
- Variable activity against viruses & fungi (not sporicidal)
- Not affected by organic debris
What is the MOA of chlorhexidine gluconate
- Low concentration = bacteriostatic (cell membrane disruption)
- High concentration = bactericidal (coagulation/precipitation of cell contents)
Elaborate on Povidone-iodine
- Elemental iodine + Polyvinylpyrrolidine
- Iodine is released for antiseptic effects
- Available as 10% solution (Dilution liberates iodine = bactericidal; must scrub @ least 2 mins to release iodine)
- Bactericidal, viricidal, & fungicidal
- Sporicidal w/ increased contact time
- Organisms do not develop resistance
- Short kill time @ low concentrations
- Some inactivation by organic debris
- Debatable residual activity
What is the MOA of Povidone-iodine
Interferes w/ microorganism metabolism, protein synthesis, & alters cell membranes
What is the one-step product
- Chloraprep - 2% chlorhexidine plus 70% isopropyl alcohol
- Duraprep - povidone-iodine + 70% isopropyl alcohol
Describe Ioban
- Iodine impregnated adhesive drape
- Apply after scrub & rinse w/ isopropyl alcohol
- Decreases bacterial contamination @ time of surgery but does not seem to affect wound infection rates
What are the main points of chlorhexidine
- Residual activity
- Rapid removal of bacteria
- Less inactivation by organic debris
- Less irritating to skin (some people have significant intolerance to chlorhexidine)
What are the main points of povidone-iodine
- Performs comparably in surgical testing
- Less expensive
- Dependent on iodine release
- Needs to be rinsed w/ alcohol
- Stains skin
Fill out the chart
Describe hydrogen peroxide
- Broad spectrum, including bacterial spores
- < 3% concentration damage tissues
- Good for removing blood stains
How should instruments be cared for
- Tools of the trade (significant investment)
- All instruments in opened back must be cleaned
- Clean instruments as soon as possible after surgery
- Inspect instruments for damage during cleaning process
What is considered damaged instruments
- Jaws do not align
- Ratchet does not click when engages first tooth
- Ratchet springs open when tapped on palm of hand
- dull scissors
- Needle drivers do not secure needle when locked on the 2nd ratchet
- Obvious damage to metal surface
What can steam not penetrate
Organic materials like grease & dried blood
What does blood do to the surface
- Corrodes the surface after 10 min contact time
- Clean instruments during surgical procedure
What type of area should there be for instruments
An ideally dedicated “clean” area to care for instruments in the clinic
What are the steps of cleaning before sterilization
- Pre-cleaning
- Cleaning
- +/- lubricating
- Packing
Label the parts
Explain pre-cleaning
- Necessary before any type of cleaning
- Rinse w/ cold water
- +/- pre rine w/ enzymatic detergent solution (can be used in place of manual cleaning; consult w/ the product for contact time usually 2 - 10 mins or 30 - 45 mins)
Describe cleaning
- Hydrogen peroxide based detergents (cleaning + microbial killing to reduce bioburden prior to sterilization)
- Detergent cleaning (water & moderately alkaline, low suds detergent)
- Ultrasonic cleaning
- Final rinse w/ de-ionized water
How should instruments be cleaning by hand
- Open all boxes
- Scrub w/ a brush
- Oil prior to air drying
Describe ultrasonic cleaning
- Open all instruments and/or take apart (need liquid to contact all surfaces)
- Non-foaming enzymatic detergen solution
- Clean through cavitation
- Rinse after to remove debris
What is cavitation
- Process where high frequency vibratory waves form gas bubbles
- Gas bubbles form & implode due to pressure waves which releases a shock of energy
- Energy creates a mini vacuum that assists w/ cleaning
What is the proper labeling of packing instruments
- Content
- Date of sterilization
- Person packing
how should packs be packed w/ muslin wraps
Double layer w/ two wraps
What is important about pima cotton
- Smaller pore size
- Re use up to 75 times
What are the main points of crepe paper
- Superior durability, handling & storage times
How should cellophane (plastic)/paper be used for packs
- single instruments
- Should double wrap (esp. large or odd shapes)
- Ends are heat sealed
- Sharp points should be protected by plastic covers
- Paper allows penetration of sterilizing medium
How should aluminum composite containers be used for packing
- Stackable
- storage for up to 1 year
- Thermal conductivity ensures dry contents
- Steam, ethylene oxide, & gas plasma sterilization
What is the open shelf life of single wrapped muslin
2 days
What is the open shelf of double wrapped muslin
3 weeks
What is the open shelf life of crepe paper
3 weeks
What is the open shelf life of heat-sealed paper & transparent plastic pouches
At least a year
What are the physical methods of sterilization
- Thermal energy
- Filtration
- Radiation
What are the chemical methods of sterilization
- Glutaraldehyde
- Ethylene oxide
- Gas plasma
- Peracetic acid
Describe dry heat thermal energy
- Kills by oxidation & desiccation
- High temperature applied for time
Describe of moist heat sterilization
- Kills by protein coagulation & denaturation
- Lower temperature applied for shorter time
what is the difference in different microbes
Different sensitivities to heat
Explain the physics behind thermal energy
- Bacterial death is logarithmic (time is as important as temperature)
- pressurized steam increases temperature & water saturation which decreases sterilization time
- Steam produces heat by condensation which increases the ability to penetrate porous objects
What is the most common method of sterilization in vet med & how does it work
- Autoclave
- Steam pressure drives air out of pressure vessels (gravity displacement)
- Newer autoclaves have vacuum system which decreases sterilization time and increase the coust of the autoclave ( pre vacumm is goof for flashing instruments)
- Is critical to achieve condensation on all surfaces & prevent air from lowering the temperature of the steam
How should instruments be placed in the autoclave
- Bowls should face down or sideways
- Valves left open
- Loosely pack
- Glass tubes seal w/ cotton plugs
What are the min guideline for sterilization
- Exposure = 15 mins
- Temp = 121 degrees C
- Pressure = 15 psi or 2 atm
- Steam autoclave
What are the guidelines of emergency sterilization (“flashing”)
- Exposure = 3 mins
- Temp = 132 degrees C
- Pre vacuum autoclave
- Should not be used for implants (plates/screws; is a risk of infection)
What are chemical autoclave indicators
- Undergo color change upon exposure to sterilizing temperatures
- Usually sensitive to time & temperature
What are biologic autoclave indicators
Culture heat resistant bacterial spores after sterilization
T/F: Indicator tape does not inform on sterility
True
What is the use of filtration for physical sterilization
- Air supply to surgery suite (laminal flow ventilation)
- Preparation of medications
- Small volumes of solution
Describe laminar air filtering system
- Air flows (.5 m/sec) over “clean” area through HEPA filter
- Exhausted out peripherally & air is re-circulated
- Decreases airborne bacterial count
- Uncommon in vet surgery suits
What do depth filters do
- Trap by a combo of random absorption & mechanical entrapment
How to screen filters filter
By pore size
Explain using radiation as a physical sterilization
- Surgical materials that are sensitive to heat or chemical sterilization
- Damages DNA & RNA
- Can change composition of plastics & pharmaceuticals
- Industrial use
Explain ethylene oxide for chemical sterilization
- Flammable & explosive liquid - effective @ sterilization (mixed w/ CO2 or freon)
- Good for equipment that can not withstand high heat or pressure (endoscopes, cameras, plastics, & power cables)
What are the recommendations of ethylene oxide
- Temp = 120 to 140 degrees F
- Humidity = 20 to 40 %
- Airation in a ventilated room for 7 days or 12 to 18 H in an airator
Is ethylene oxide toxic to people
Yes
Explain using gas plasma for chemical sterilization
- Liquid hydrogen peroxide is changed to vapor
- Wrap in plastic pouches or nonwoven polypropylene fabric
What are the advantages of gas plasma
- Sterilize @ low temps & short time intervals
- no aeration
- Available right away
- Safe
What is gas plasma used for
- Stainless steel
- Aluminum
- Brass
- Silicone
- Teflon
- Latex
- Polyethylene
- Polypropylene
- PVC
- Polymethymethacrylate
What is gas plasma not used for
- Anything that will absorb H2O2
- Linen
- Gauze
- Wood
- Paper
- Endoscopes
- Some plastics
- Items that can’t be disassembled
- catheters > 12 in
- Anything < 3 mm diameter
Explain the use of peracetic acid for chemical sterilization
- Kills bacteria, viruses, fungi, & spores
- 10 to 15 min contact
- 0.09% concentration
- Does not create biofilm
- Not affect by organic material
- Can remove glutaraldehyde-hardened material from biopsy chamber
What are STERIS system 1 E
- 25 min sterilization cycle
- Flexible endoscopes
What is the MOA of Glutaraldehyde
- Protein & nucleic acid denaturation
- bactericidal, fungicidal, & viricidal ( > 10 H for sporidical; effectiveness pH, temp, & is concentration dep
- Antimicrobial activity increases w/ temp & decreases w/ organic material
Explain how glutaraldehyde is a tissue irritant
- Sensitivity/allergic reactions
- Rinse w/ sterile water prior to use
- Vapors cause mucous membrane irritation
Explain Glutaraldehyde
- Most effective @ alkaline pH but this reduces shelf-life
- added activator (colored)
- Quality control w/ test strips (dilution over time from water off instruments & activator solution)
- Prolonged use may corrode metal & some plastics & can create biofilms
What are the used glutaraldehyde
- Equipment that cannot be exposed to heat (not as effective as ethylene oxide)
- Quick sterilization of dropped instrument (10 to 15 min soak time)
- General cleaning
How should instruments be cared for in the field
- Clean after procedures w/ water from the truck
- Instruments kept in chlorhexidine or providone iodine (during surgery, not recommended to store like this, & not sterile)
