Chapter 7 - Disinfection, Decontamination, and Sterilization (part 2)
Asepsis
The absence of of pathogenic microorganisms
bacteriocidal
substance that destroys/kills bacteria
bacteriostatic
substance that inhibits the growth and reproduction of bacteria
bioburden
the number of microbes or amount of organic debris on an object at any given time
contamination
the presence of pathogenic materials
cross-contamination
the contamination of a person or object by another
decontamination
to reduce to an irreducible minimum the presence of pathogenic material
disinfectant
chemical agent that kills most microbes, but usually not spores; used on inanimate objects because compounds are too strong on living tissues
*is a category of disinfection
event-related sterility
determined by how a package is handled; package is considered sterile until opened or integrity of package material is damaged
*mostly used now, except implants still have expiration dates
*dust covers gave an extra 6 months on expiration
fomite
inanimate object that harbors microorganisms
fungicide
agent that destroys fungus
infection
invasion of the human body or tissue by pathogenic microorganisms that reproduce and multiply, causing disease
nosocomial
infection acquired within a health care facility - HAI
pathogen
any microbe capable of causing disease
resident flora
microbes that normally reside BELOW the skin surface or WITHIN the body
transient flora
microbes that reside ON the skin surface and are EASILY REMOVED
*we try to lower their numbers for surgery to obtain surgically clean
sepsis
infection, usually accompanied by fever, that results from the presence of pathogenic microorganisms
spore
a resistant form of certain types of bacteria that are able to survive in adverse conditions
sporicide
liquid substance that kills/destroys bacteria in the spore stage
sterile
having been rendered free of all living microorganisms, including spores
sterile field
specified area, usually the area immediately around the patient, that is considered free of microorganisms
sterile technique
techniques of creating a sterile field and performing within the sterile field to keep microbes at an irreducible minimum
strike-through contamination
contamination of a sterile field that occurs through the passage of fluid through, or a puncture in, a microbial barrier
surgically clean
mechanically cleaned and chemically disinfected but not sterile
terminal disinfection
to render item safe to handle by high-level disinfection
*not used invasively
terminal sterilization
to render items safe to handle by sterilization
*used invasively
vector
living carrier that transmits disease
ex: mosquitos (west nile virus)
virucide
agent that destroys viruses
CDC and FDA classification system for patient care items and surgical devices
Critical
Semi-Critical
Non-Critical
surgical instruments, devices that enter the vascular urinary systems, and any monitors or prove that enter deep tissue layers or cavities.
needles, catheters, implantable items (wires, screws, joint replacements, sutures)
Critical patient care items
Antisepsis
process in which most but not all microorganisms located on animate surfaces, such as the skin, are destroyed
Semi-Critical patient care items
items that come into contact with mucous membranes or non-intact skin carry a lesser risk of infection
laryngoscopes, anesthesia and respiratory equipment, and some endoscopes. High-level disinfection should be used
Non-Critical patient care items
items that come into contact with a patient's intact skin. Least risk of infection
blood pressure cuffs, pulse oximeters, OR transport stretchers, and other furniture. Intermediate-level to low-level disinfection
AST recommended standards of practice applicable to decontamination and sterilization
RSOP:
for the Decontam. of Instruments
for Packaging Material and Preparing Items for Sterilization
for Monitoring Sterility
Disinfecting Agents
Disinfecting agent: CLEANING
physical removal of blood, body fluids, gross debris (fat, tissue) (Bioburden)
Disinfection agent: DISINFECTION
destruction of pathogenic microorganisms by direct exposure to chemical or physical agents.
*Three levels of disinfection
Disinfection agent: HIGH-LEVEL DISINFECTION
kills all microorganisms except spores and prions (CJD)
*scope washers
Disinfection agent: INTERMEDIATE-LEVEL DISINFECTION
kills most microorganisms, including bacteria, most viruses and fungi. M. Tuberculosis and HBV: ineffective against spores
Disinfection agent: LOW-LEVEL DISINFECTION
kills some fungi and viruses, and most bacteria, but is not effective against spores and M. tuberculosis
Disinfection agent: STERILIZATION
destruction of all microorganisms in or about an object with steam (flowing or pressurized) chemical agents (alcohol, phenol, heavy metals, or ethylene oxide gas) high-velocity electron bombardment, UV
disinfectant compounds also serve as sterilants when used in sterilization systems
Peracetic acid - used in Steris system
*liquids - items immersed to the liquid for certain amount of time
factors that influence efficiency of disinfectants
Disinfectant concentration is too high
*increases the level of disinfection
*too corrosive for use on rubber
effectiveness of disinfection is decreased on contaminated items
*blood, body fluids, or tissue present on an item can make disinfectant difficult to be effective. - unable to contact surface
*must contact all surfaces
*thoroughly cleaned prior to decontamination process
*instruments disassembled, ratchets and locks opened
20-30 minutes
contact time that is generally recommended for high-level disinfection
10-15 minutes
contact time that is recommended for intermediate and low-level disinfection
safety with handling disinfectant solutions
High-level disinfectant **can also be used as a sterilant
Glutaraldehyde
also known as Cidex
one of the best overall disinfectant/liquid sterilants on the market
used on devices that can withstand immersion in the liquid
used with decontamination or sterilization of rigid and flexible endoscopes
shelf life
Glutaraldehyde's is 14 days; with a surfactant it increases to 28 days and must be tested prior to each day during the 14-28 day period
the period of time between activation of the disinfection solution or number of uses after which the efficiency is diminished - must be at 2% strength - tested with test strips
requirements for items prior to being immersed in glutaraldehyde
immersed 20 minutes at room temperature for high-level disinfection
or
immersed 10 hours for sterilization
Glutaraldehyde's exposure times
glutaraldehyde - alkylation of cell protein
ADVANTAGES
dual purpose (disinfectant and sterilant)
noncorrosive to metals, lensed and cemented items, rubber and plastic
bactericidal against gram + and gram- microbes, tuberculocidal, virucidal
glutaraldehyde - alkylation of cell protein
DISADVANTAGES
noxious odor
irritating vapors
unstable shelf life
items must be cleaned and dried prior to immersion
Sodium Hypochlorite - household bleach - disrupts cellular metabolism
high-level disinfectant
effective fast-acting disinfectant solution for surfaces, floors, and equipment.
recommended by the CDC to clean blood and body fluid spills
Sodium Hypochlorite - high-level disinfectant
ADVANTAGES
bactericidal, virucidal, tuberculocidal, effective against HIV, HBV, and other viruses
Sodium Hypochlorite - high-level disinfectant
DISADVANTAGES
Noxious odor
corrosive
harmful to the skin
loses effectiveness in the presence of organic soil
Intermediate-level disinfectant compounds
capable of killing spores or certain hydrophilic viruses; however, they do kill all bacteria, fungi, and non-hydrophilic viruses.
used to disinfect countertops, OR furniture, floors, and other surfaces, and instruments that only come into contact with the skin of the patient
Phenol (Carbolic Acid) - denatures enzymes and causes cell lyses
intermediate-level disinfectant
used as a concentrate with detergent additives and is diluted with tap water. Used to disinfect large areas (floors and countertops) on a general basis.
Phenol (carbolic acid)
ADVANTAGES
economical choice for the OR because it is a highly concentrated solution that is easily diluted
effective in eliminating fecal contamination
Phenol (carbolic acid)
DISADVANTAGES
Highly irritating to the skin - isopropyl alcohol should be used to neutralize
noxious odor
respiratory tract irritant
limited to disinfection of noncritical items
Quaternary Ammonium Compounds - cause leakage of the protoplasm in microbes
Intermediate-level disinfectant
they are commonly called quats, are bactericidal, fungicidal, and pseudomonacidal - unable to kill TB, spores, or viruses
Quaternary Ammonium Compounds
ADVANTAGES
low cost
easy to mix
odorless
noncorrosive
Quaternary Ammonium Compounds
DISADVANTAGES
kill limited number of classes of microbes
effectiveness easily reversed when solution contacts organic debris tap water, or detergents
gauze or fabrics absorb the disinfectant rendering it ineffective
Alcohol - causes protein denaturation, lysis, and metabolic interruption of cells
intermediate-level disinfectant
Isopropyl and ethyl alcohol in a dilution of 60-70% alcohol concentration are tuberculocidal, bactericidal, virucidal, and fungicidal; they are not sporicidal
Alcohol
ADVANTAGES
nontoxic to the skin
effectively reduces number of bacteria on the skin - skin prep
good range of effectiveness against several types of microbes including HIV
Alcohol
DISADVANTAGES
slight odor
do not use to clean surgical instruments - highly corrosive
do not use to clean endoscopes - breaks down cement
highly flammable!
OSHA exposure control plan
explains the protective measures needed to create a safe working environment
A routine schedule should be established for the cleaning and decontamination of OR surfaces, scrub sinks, cabinets, floors, walls, and ceilings - Joint Commission will inspect
Decontamination practices in the OR : prior to the first procedure of the day
Decontamination practices in the OR : intraoperative
Decontamination practices in the OR: between procedures
turnover - which marks the preparation for the next procedure
Terminal cleaning
end-of-day cleaning routine. A thorough cleaning of the rooms and areas outside of the OR after the last case of the day has been completed.
Zambonium - a machine to clean the OR floor.. floors are usually flooded, beds are broken down to power wash them
Other area of the surgical department that should be cleaned
substerile and storage rooms
stretchers for transporting
scrub sinks - due to their heavy use
hallway floors - cleaned similar to the OR floors
**scrub solution dispensers - gram negative bacilli have been known to contaminate disinfectant solutions and soap dispensers in the OR
Weekly cleaning in the OR
Dirty Cases - last procedure of the day in an OR so a thorough terminal cleaning process will occur
floor should be cleaned with phenolic detergent
equipment and furniture - wiped with 70% alcohol
First step in the prevention of the transmission of microbes
Critical patient item or instrument that will be used on open tissue or be placed in the sterile field must be sterilized to remove all microbes, including spores
decontamination process
Decontamination room
a separate area, usually in proximity to the clean sterile processing area. The design of the decontamination area environment should follow these principles:
The first step in the decontamination process begins
at the point of use
ST responsible for pre-soaking contaminated instruments to prevent drying of organic matter...
advantages of presoaking solutions
sterile water - keeps organic debris moist
enzyme - removes moistened and dried debris w/o the need for mechanical action
detergent - keeps organic debris moist while loosening dried-on debris
limitations of presoaking solutions
sterile water - ineffective in softening or removing dried debris
enzyme - efficiency depends on concentration of solution, temperature, and contact time
detergent - mechanical action is necessary to completely remove soil
when cleaning instruments, remove organic and inorganic soil through one of the following methods, depending on the type of cleaning solution used
chelation
enzymatic
emulsification
solubilization
chelation
process of binding minerals in the solution. this prevents their deposit on the surface of surgical instruments, which causes spotting
enzymatic
catalysts that aid in breaking down organic soil such as blood and tissue into solution
emulsification
action o dispersing two liquids not capable of being mixed
solubilization
action by which the solubility of a substance is increased within a solution
common chemical cleaners:
Enzymatic
organic substance that aids in the chemical reaction of breaking down organic debris.
specific to type of debris to be removed
more effective in warm water
common chemical cleaners:
Ultrasonic
specifically for use in ultrasonic cleaners.
may contain a surfactant (to enhance wetting ability) and chelating agents
common chemical cleaners
Manual detergent
products usually used for hand cleaning of items and/or presoaking. Some of the manual cleaners are high foaming and therefore should not be used in mechanical cleaning equipment.
mechanical action is required to assist in removing the soil. Surgical instruments must be thoroughly rinsed after being placed in the detergent
common chemical cleaners
Washer-decontaminator
liquid solution that is available in three different pH levels.
Neutral-ph= least corrosive/less effective
Moderate-ph= low-level alkaline, may be combined w/surfactants and chelating agents. Safe on SS instruments but harmful to the chromium oxide layer that protects instruments from corrosion
High-pH= most effective/corrosive, must be neutralized
cleaning - the first step in decontamination
ideally this trio arrangement is utilized
First sink: wash sink with water and detergent
Second sink: intermediate rinse with distilled water
Third sink: final rinse with distilled water
Manual cleaning of instruments is a three-step process
---instruments are immersed in a solution of lukewarm water, detergent, and/or enzymatic cleaner with a neutral pH. Avoid hot water to avoid blood and tissue from being set on surface
---The last step is to rinse the instruments in distilled water
---To avoid spotting the instruments, the items should be immediately dried after rinsing
Mechanical cleaning... recommendations for preparing instruments for the washer-sterilizer, washer-decontaminator, or ultrasonic washer
---instruments must be placed into a perforated or wire mesh tray
---heavier instruments should be placed on bottom, delicate on top
---hinged instrument must be left in an open position to allow water, cleaning agent, and steam to contact the total surface area
---instruments with attachments must be dissembled
---instruments with concave surfaces should be placed upside down to allow proper cleaning, rinsing, steam contact, and drainage
Washer-Decontaminator
*does not incorporate a sterilizing phase
*4 cycles - prerinse, cleaning, final rinse 180-195 degrees, and drying phase
Washer-Sterilizer
*gross soil is removed then processed in here
*SS instruments not placed next to other metals-reaction could damage instruments
*low-sudsing only - high-sudsing will leave a residue
*8 cycles - presinse, automatic detergent injection fill phase, wash phase, postrinse, sterilization phase, lubrication (milking), drying phase
Ultrasonic Cleaner
Used to remove small organic particles and soil from areas of instrumentation that manual or mechanical cleaning cannot reach. ex: box locks, serrations, and ratchets
Utilizes cavitation for cleaning insruments
cavitation
Instrument preparation
here in the "clean room" (CSPD) is where instruments are checked for function and integrity and prepared for sterilization
Advantages to non-woven materials
Impervious to moisture = waterproof
types of pouch packaging used by health institutions
Paper-plastic combinations that are used for steam and EtO sterilization
Tyvek-plastic combination used for EtO (only) and Sterrad
Reusable rigid instrument containers with locking lids have become popular with health care facilities. The containers are multipurpose and have the following characteristics:
ANSI/AAMI
recommends that instrument sets should not exceed 25#
Preparation of instruments include:
*One of the steps is proper inspection of powered instruments
*An instrument may need to be lubricated and operated for a designated amount of time to ensure lubricant distribution. The power hose should be checked for cracks and cuts. The power hose should be coiled loosely to prevent kinking and damage.
Preparation of instruments for effective sterilization..If done properly will ensure:
How should instruments be placed:
A mesh-bottom or wire mesh basket with an absorbent towel lining the bottom
instruments that need special preparation prior to sterilization
instruments with lumens, such as a Frazier suction tip, may have air trapped in the lumen and may prevent steam from contacting the inner surface. To prevent this entrapment of air, a residual amount of distilled water should be left inside the lumen.
more special preparations of instruments prior to sterilization
basin sets are conducive to the formation and retention of condensate due to their density. Basins that will be nested within each other or that may contain other metal items must have adequate air space between each item. An absorbent towel should be used to separate the basins and items. It should be fully opened to absorb the condensate, to aid in air removal, and to create an adequate space for the penetration of steam. A towel should also be used to separate items from each other in the basin.
Julian date
indicates the date of sterilization. It is the number of the calendar day 1-365/366
Steam Sterilization
the destruction of all microorganisms in or about an object can be accomplished with the use of steam under pressure.
dependable and inexpensive method
Methods of sterilization
Chemical agents (alcohol, phenol, heavy metals, and ethylene oxide gas,) high-velocity electron bombardment, or UV radiation.
How are microbes killed
*heat alone is sufficient, but the process is accelerated with the addition of moisture and pressure. Pressure that is greater than that of the atmosphere is necessary to increases the temperature of the steam in order to cause the destruction of microbes.
Factors that are critical to the outcome of the sterilization process
sterilization failures
Containers are posiitoned incorrectly on the cart. Instrument trays, basins, and peel packs must be positioned to allow air to escape
wrapped packs are placed too close together on cart. Packs should be loosely arranged on the autoclave cart to allow complete removal of trapped air and free circulation of steam
components of an autoclave
some generate their own steam, but others rely on an outside source. When this happens the walls of the chamber are preheated before the steam is allowed into the chamber. This is accomplished with a metal jacket that is built around the chamber. The space between the jacket and chamber is filled with steam to preheat the chamber walls when the machine is turned on.
Gravity displacement sterilizer
rely on gravity to passively remove air from the sterilization chamber. Steam enters at the top of the chamber and displaces the air. Air is heavier than steam, so as the steam occupies more space, the air is pushed out the drain at the bottom front of the chamber. The pressure in the chamber increases the temp. of the steam reaches a preset temperature.
these are slower than prevacuum/dynamic-air removal sterilizers because gravity is relied on to remove the air.
Bowie-Dick test
named after two English microbiologists
J.H.... ad J....
This test is used in the prevacuum sterilizer to check for air removal and entrapment and is conducted daily on the first run of the day before any loads are sterilized or after it has undergone repair
Immediate use or "flash" sterilization
unwrapped items, such as instruments that have been dropped during a procedure.
*can be performed in a gravity or prevacuum sterilizer
advantages of steam sterilization
saturated steam is many times more effective in transferring thermal energy than hot air
most economical and inexpensive
safest
dynamic-air removal (prevacuum) steam sterilization cycle times
instrument set wrapped
270 degrees for 4 minutes
gravity displacement steam sterilization
instrument set wrapped
270 degrees for 15 min.
methods of monitoring the sterilization process
chemical indicators
consists of paper that has been impregnated with a dye that changes color in the presence of temperature and sterilant
Internal steam chemical indicators
placed inside packages, peel pack, and instrument trays to indicate the contents have ben exposed to the conditions of sterilization.
available as commercial strips of paper impregnated with ink
should be placed in the area of the package or tray where the greatest challenge exists for penetration of steam an air removal.
It is read when the package or tray is opened at time of use
Biological indicator (BI)
*a device that contains a specific type of microorganism that is killed when exposed to the sterilization conditions
*contains the spore "Geobacillus stearothermophilus"
*incubated for 24hours before the reading is recorded
where is the (BI) test pack placed
area of the sterilizer that is most difficult for the sterilant to reach. The "coldest" area where air entrapment is most likely to occur. This is the bottom front of the sterilizer cart over the chamber drain.
EtO Ethylene Oxide
gas sterilant used to process materials that cannot be processed using steam sterilization, such as heat or moisture sensitive materials.
EtO factors for proper sterilization
humidity: moisture hydrates spores and bacteria that would otherwise be resistant to the gas alone. Humidity is kept between 30-80%
Moving EtO loads
loads from this sterilizer must be pulled instead of pushed to avoid the possibility of "downwind" of the fumes
*EPA concerned personnel safety with its use. It's CFCs damaging to the ozone layer
*OSHA developed strict PEL with its use
Advantages of EtO
used for heat sensitive materials
less corrosive to metals
less damaging to plastic and rubber
Disadvantages of EtO
aeration times an be lengthy - up to 21 days with pacemakers
personnel hazards
(BI) for EtO
Bacillus atrophaeus
(BI) for Hydrogen Peroxide gas plasma
Bacillus atrophaeus
(BI) for Peracetic acid
Geobacillus steraothermophilus
Hydrogen Peroxide gas plasma limitations
difficulty with narrow-lumen or channeled instruments of sterilant reaching the innermost surfaces
HPGP (hydrogen peroxide gas plasma) packaging
must be made of nonwoven polypropylene or other synthetic, non-cellulose, nonwoven material. Peel packages made of Tyvek are appropriate for use.
Peracetic acid
skin tumors in mice
used with Steris maching 122degrees
used for rigid and flexible endoscopes
used for single sterilization cycle ***FOR IMMEDIATE USE ONLY"
cannot be stored!
impregnated strip "wash-off"
chemical strips detect that the active ingredient is present in greater than 1500 parts per million are available for routine monitoring of concentration levels
ionizing radiation
used by industrial manufactures to sterilize prepackaged products for use in the OR and hospital environment. Uses a process of irradiation to produce thermal and chemical energy, killing microbes/spores. Gamma Rays or Beta particles to sterilize
Manufacture does not use chemical indicators...pkg. integrity is the method for determining sterility
Event-Related sterility
replaced older time-related system. It is determined by how it is handled and that contamination is not by expiration.
economical for healthcare facility. It eliminates pulling expired items from shelves.
Principles are synonymous with
action/practices
Principles and practices/actions of sterile technique
designed to protest the sterile field from contamination and keep microbial counts to an irreducible minimum
Surgical conscience
basis for the practice of strict adherence to sterile technique by all surgical team members. It involves a level of honesty and moral integrity that every surgical technologist must uphold in order to deliver quality patient care
"There can be no compromise of sterile technique"
safety of patient depends on strict adherence to this practice. And other members of the surgical team.
Adherence to asepsis aids in preventing SSIs
understanding of microbiology, disease transmission, cross-contamination, disinfection and sterilization
Primary method through which microbes are kept to a minimum in the OR
Sterile field
A separate sterile area that consists of the surgical site itself, draped portions of the patient, OR table, sterile portions of the gown and gloves, draped ring stands, Mayo stand, and back table. Sterile instruments, sutures, an equipment to be used during the procedure
Inside of the paper wrappers containing linens or other sterile items is considered sterile except...
1 inch perimeter around the outside edge of the wrapper
The integrity of sterile packaging must be checked before opening
No evidence of strike-through, tears, or punctures, all seals must be intact; and CIs must have turned color to indicate exposure to sterilizing conditions
The surgical gown is considered sterile in front 2 inches below the neckline to table level; bilaterally; and sterile gloved hands to 2 inches above elbows
upper chest area on the front of the gown is considered nonsterile because it cannot be directly viewed by the wearer and because of the possibility of the chin coming into contact with this part of the gown
Sterile surgical team members should either pass while facing one another or pass back to back by rotating 360 degrees
The ST should turn her or his back to a nonsterile individual or area when walking past
A nonsterile individual must maintain a minimum distance of 12in. from any sterile item, area, or field to prevent contamination
additionally, equipment and furniture that is not covered by a sterile drape must not be included in the sterile field and must be kept a minimum of 12 in. away from a sterile surface pr item. The ST must be conscious of these nonsterile items and personnel and maintain the 12 in. distance
When draping a nonsterile table to create sterile field the nonsterile individual should cuff the hands in the underside folds of the drape or table cover to avoid contaminating the top surface
drape should be opened away from the body toward the far side of the table and then toward the body to avoid contamination