Sterilization

Question 1

Advantages of OPA over glutaraldehyde

Answer 1

• not an irritant to eyes/nasal passages
• no activation required
• no exposure monitoring
• 12 min HLD claim

Question 2

Factors affecting efficacy of disinfection and sterilization

Answer 2

• > # of microbes the more time a germicide needs
• prions and bacterial spores possess innate resistance to chemical germicides
• the more concentrated the disinfectant the greater efficacy and shorter time necessary
• temperature increase, increases disinfectant activity
• increase pH can increase/decrearse antimicrobial activity
• relative humidity effects gaseous disinfectants
• water hardness reduces rate of kill due to divalent cations
• organic material either protects bacteria or reacts with germicide
• biofilms are 1,000x more resistant to antimicrobials

Question 3

Alcohol disinfection

Answer 3

• optimum concentration is between 60-90%
• bactericidal not bacteriostatic
• not recommended for sterilizing medical/surgical equipment
• cannot penetrate protein rich material
• damage shellac mountings of lensed instruments
• swells/hardens rubber materials
• bleach rubber and plastic tiles
• flammable and require cool, well ventilated storage
• evaporate quickly

Question 4

Chlorine compound disinfection

Answer 4

• broad spectrum of antimicrobial activity
• do not leave toxic residues
• unaffected by water hardness
• inexpensive and fast acting
• removes dried or fixed organisms and biofilms
• corrosiveness to metals
• inactivated by organic material
• releases toxic gas when mixed with ammonia or acid
• decontaminates blood spills
• disinfects water distribution in hemodialysis centers/machines
• can be stored at room temp in opaque container but will lose 50% of chlorine levels
• when stored in closed brown bottle, not decomposition for 30 days

Question 5

Formaldehyde disinfection

Answer 5

• used both in liquid and gaseous states
• formaldehyde-alcohol is a chemical sterilant
• formaldehyde is a HLD
• healthcare uses are limited due to irritating fumes and pungent odor at low levels

Question 6

Glutaraldehyde disinfectant

Answer 6

• HLD and chemical sterilant
• needs to be activated
• short shelf life (14 days)
• 2.5% glutaraldehyde at 35*C reduces time to required to achieve HLD (5 min) but is limited to AER
• used most commonly as a HLD for medical equipment such as endoscopes, dialyzers, transducers, anesthesia and respiratory laparoscopic plastic trocars.
• noncorrosive to metals and does not damage lensed instruments, rubber or plastics

Question 7

Hydrogen Peroxide disinfectant

Answer 7

• under normal conditions is extremely stable when stored in dark containers
• ## 3% is stable and effective disinfectant when used on inanimate surfaces

Question 8

Iodophor disinfectant

Answer 8

• antiseptic and disinfectant
• best known and most widely used is povidone-iodine
• iodophors have been used for disinfecting blood culture bottles and medical equipment such as hydrotherapy tanks, thermometers and endoscopes

Question 9

OPA disinfectant

Answer 9

• exposure time is 12 minutes
• HLD label claims at 20*c vary worldwide
• In AERs with FDA cleared ability to maintain solution temps at 25*c, contact time is 5 minutes

Question 10

Peracetic Acid disinfectant

Answer 10

• lacks harmful decomposition products
• enhances removal of organic materias
• leaves no residue
• sporicidal at low temps
• corrodes coppor, brass, bronze, plain steel and galvanized iron
• there is an automated machine that uses to chemically sterilize medical, surgical, and dental instruments

Question 11

Peractic acid and Hydrogen peroxide disinfectant

Answer 11

• used for disinfecting hemodialyzers

Question 12

Phenolics

Answer 12

• absorbed by porous materials
• residual material can irritate tissue
• not FDA cleared as a high-level disinfectant for semi-critical items
• can be used to preclean or decontaminate critical and semi-critical devices

Question 13

Quats

Answer 13

• good cleaning agent
• high water hardness and materials such as cotton and gauze pads can effect microbicidal activity
• commonly used in ordinary environmental sanitation of noncritical surfaces and medical equipment that comes in contact with intact skin

Question 14

Pasteurization

Answer 14

not a sterilization process
purpose is destroy all pathogenic microorganisms except bacterial spores
time-temp relation for hot water pasteurization is generally 70*C for 30 minutes

Question 15

Steam Sterilization - general overview

Answer 15

• inexpensive, nontoxic, rapidly microbicidal, sporicidal, rapidly heats and penetrates fabrics

Question 16

Steam sterilization 4 parameters

Answer 16

• Steam: should be dry saturated and entrained water
• Pressure: Serves as means to obtain the high temps necessary
• Temperature: common temps are 121* & 132*
• Time: 30 min for 121* gravity displacement or 4 minutes at 132* prevacuum

Question 17

Gravity displacement autoclave

Answer 17

steam is admitted at the top or the sides of the sterilizing chamber and because the steam is lighter than the air, forces the air out of the bottom of the chamber through a drain vent

primarily used for processing laboratory media, water, pharmaceutical products, regulated medical waste, and nonporous articles whose surfaces have direct steam contact

Question 18

Prevacuum autoclave

Answer 18

similar to gravity displacement, except fitted with vacuum pump that ensures air removal from the chamber and load before the steam is admitted.

advantages are there is nearly instantaneous steam penetration

require bowie-dick test to detect air leaks and inadequate air removal each day before the first load

Question 19

Chemical indicators

Answer 19

affixed to the outside and incorporated into the pack to monitor the temperature or time and temperature.

Question 20

Biological indicator

Answer 20

effectiveness of the steam sterilization using Geobacillus stearohermophilus spores.

Question 21

Flash sterilization (IUSS)

Answer 21

steam sterilization of an unwrapped item at 132* for 3 minutes at 27-28 lbs.

Question 22

Ethylene oxide “gas” sterilization

Answer 22

disadvantages include lengthy time cycle, cost, potential hazard to patient and staff

advantages: able to sterilize heat- or moisture-sensitive medical equipment without deleterious effects

requires mechanical aeration for 8-12 hours to desporb the toxic ETO residues

Question 23

Hydrogen peroxide gas plasma

Answer 23

deep vacuum with radio frequency or microwave energy to excite gas molecules and produce charged particles which interact with essential cell components and disrupt metabolism of the microorganisms.

biproducts are nontoxic and therefore do not require aeration.

Question 24

decontamination area

Answer 24

must be physically separated from other sections

negative pressure

no fewer than 10 ACH

Question 25

packaging area

Answer 25

intended for inspecting, assembling, and packaging clean BUT NOT STERILE materials.

Question 26

Sterile storage area

Answer 26

limited access area

• temperature <75*C
• relative humidity 30-60% not to exceed 70%
• storage at least 8 in from ground, 5 in from ceiling, 2 in from outside walls