Cleaning, Disinfection, Sterilization, Asepsis (18 exam questions)

Question 1

Process for transporting surgical instruments to decontamination

Answer 1

1. Clean off gross debris (bio burden) ASAP by wiping or irrigation (per IFU) with water with detergent or enzymatic. Keep moist
2. Pre-soaking, transported in leakproof, puncture-proof container with biohazard label. (or case cart for surgical instruments)
3. Manually or mechanical clean. Manually: use friction and neutral detergent under pressure (fluidics). Mechanical clean uses alkaline detergent

Question 2

Non-critical (Spaulding classification)

Answer 2

contact with intact skin, not mucus membrane. Requires intermediate and low level disinfection (ex: stethoscope)

Question 3

Semicritical (Spaulding classification)

Answer 3

Will contact mucous membranes or nonintact skin (Ex: RT or anesthesia equipment and some endoscopes)
* Should be free of all vegetative microorganism, but small number of spores may be present
* items require HLD with chemical disinfectant
*

Question 4

critical (Spaulding classification)

Answer 4

involve high risk for infection if contaminated with microorganisms - enter sterile tissue, bone or vascular system

Question 5

Sterilization

Answer 5

destroys all microorganisms, INCLUDING spores
* High- steam
* low- ethylene oxide
*Liquid immersion- chemical sterilant

Question 6

High level disinfection

Answer 6

destroys all microorganism, EXCEPT high number of spores
* heat- automated- pasteurization
* liquid immersion- chemical sterilant

Question 7

Intermediate level disinfection

Answer 7

destroys vegetative bacteria, mycobacteria, most viruses, most fungi, NOT spores
* Liquid contact- EPA registered disinfectant WITH tuberculocidal claim

Question 8

Low level disinfection

Answer 8

destroys most vegetative bacteria, some fungi and viruses, NO mycobacteria or spores
* Liquid contact- EPA registered disinfectant WITHOUT tuberculocidal claim

Question 9

Temp of steam sterilization

Answer 9

250°F (121°C) and 272°F (133°C)

For steam sterilization, you have to consider pressure, temperature, time, and moisture, The temperature must reach ____ to ensure the microorganisms are killed

Question 10

Ethylene oxide (ETO)

Answer 10

exposure concern, long cycle (3-6 hours)

Question 11

Glutaraldehyde

Answer 11

HLD
inexpensive, excellent material compatibility, 5-45 min cycle

Question 12

Ortho-phthalaldehyde (OPA)

Answer 12

HLD that does not have a significant odor and generally does not cause respiratory irritation.
Drawbacks of OPA are that it can cause staining if it come in contact with skin, clothes, or surfaces and it is relatively expensive.

Question 13

Vaporized hydrogen peroxide

Answer 13

safe for environment and HCW, no toxic residue, fast cycle (55 min)

Question 14

Sterilization mechanical indicator

Answer 14

recording charts for time and temp, pressure gauges

Question 15

Sterilization chemical indicator

Answer 15

chemically impregnated paper or strips, pellet in glass tube

*Bowie Dick test: used to check removal of air from sterilizer and efficacy of vacuum pump

Question 16

Sterilization Biological indicator

Answer 16

spore strips Bacillus stearothermophilus or Bacillus subtilis

A biological indicator is the only method of assuring that a steam
sterilizer has reached the correct conditions to ensure sterility of products.

To determine whether the items being autoclaved are properly
sterilized, which is indicated by a negative BI result

Rationale: A biological indicator is a standardized, contained population
of microbes that is included in a sterilization cycle to indicate whether the
cycle was successful. The BI may contain spore-forming bacteria or other
highly resistant microbes, and sterilization should render these microbes
inactive. After sterilization, a BI is incubated at the optimum temperature
and time for growth of the microbe. A positive result occurs from microbial
growth, which indicates that the sterilization cycle was not optimal for
inactivation of all microbes.

*AAMI recommends biological indicator used in 1st load of each day (preferred) but at least once per week
* Causes of false-positive: accidental contamination of sterilized test strip in lab, defective biological indicator, contamination of growth medium with bacillus spp.

Question 17

Steps for disinfection or sterilization (chemical sterilant or HLD)

Answer 17

1. Clean: mechanically clean and flush all channels with water and enzymatic cleaner.
2. Disinfect: immerse in HLD or chemical sterilant for time recommended on IFU
3. Rinse: with sterile water, filtered water or tap water
4. Dry : rinse channels with alcohol and dry with forced air
5. Store: in a way to prevent recontamination and promote drying (hung vertically)

Question 18

Tonometer (semi critical item) disinfection

Answer 18

1. wipe clean and disinfect for 5-10 min with 5000 ppm chlorine or 70% ethyl alcohol
2. thoroughly rinse in tap water and air dry before use

Question 19

Diaphragm fitting rings (semi critical item) disinfection

Answer 19

1. Clean with soap and water
2. 15 min immersion in 70% alcohol

• should be adequate to inactivate HIV, HBV, HSV even though alcohols are not classified as HLD

Question 20

probes (endocavity, US) (semi critical) disinfection

Answer 20

• use a probe cover
• HLD via liquid sterilant or sterilized between patients

*cryosurgical probes are not fully immersible

Question 21

Which of the following is the best method for removal of all microbes from an instrument that is heat stable and water resistant

Answer 21

Steam Sterilization.

Steam sterilization involves the use of moist heat under pressure to raise the temperature in a sterilizer quickly to a critical temperature that will destroy all microbes, including spore formers. The process is relatively fast and is automated so it’s generally reliable. Instruments that can withstand exposure to high heat and moisture should be steam sterilized.

Reference: Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 Rutala WA, Weber DJ, Healthcare Infection Control Practices Advisory Committee

Question 22

Decontamination is the process by which an item is

Answer 22

Rendered safe for handling without protective attire.

Decontamination according to OSHA, is defined as “the use of physical or chemical means to remove, inactivate, or destroy bloodborne pathogens on a surface or item to the point where they are no longer capable of transmitting infectious particles and the surface or item is rendered safe for handling, use, or disposal” [29 CFR 1910.1030]. In health-care facilities, the term generally refers to all pathogenic organisms.

Question 23

If your only consideration in choosing a chemical disinfectant was to select one that does not irritate the respiratory system, which of the following would you choose

Answer 23

Ortho-phthalaldehyde (OPA).

Ortho-phthalaldehyde (OPA) is a high-level disinfectant that does not have a significant odor and generally does not cause respiratory irritation. Drawbacks of OPA are that it can cause staining if it come in contact with skin, clothes, or surfaces and it is relatively expensive.

Question 24

leared by the U.S. Food and Drug Administration (FDA) and are dependable high-level disinfectants provided the correct parameters for time and temperatures are me

Answer 24

Glutaraldehyde, hydrogen peroxide, ortho-phthalaldehyde, improved hydrogen peroxide, peracetic acid with hydrogen peroxide, and chlorine-based products

Question 25

The Association for the Advancement of Medical Instrumentation (AAMI) has proposed the use of ________ the benchmark for residual protein on medical and surgical instruments following cleaning of an instrument prior to sterilization.

Answer 25

< 6.4 µg/cm2as

Question 26

Inadequate sterilization of surgical instruments and tubing may result in which of the following adverse events after cataract surgery?

Answer 26

Toxic Anterior Segment Syndrome Rationale: Toxic Anterior Segment Syndrome (TASS) is an acute inflammation of the eye that can occur following cataract surgery. A variety of substances have been implicated as causes of TASS and include impurities of autoclave steam, heat stable endotoxin, and irritants on the surfaces of intraocular surgical instruments. General principles of cleaning and sterilizing intraocular surgical instruments have been published and should be followed.

Question 27

disadvantage of liquid sterilization

Answer 27

Items cannot be wrapped during the sterilization process so sterility cannot be maintained during storage Rationale: Liquid sterilization uses glutaraldehyde, hydrogen peroxide, or peracetic acid to sterilize items that are critical and are heat-sensitive. This is a liquid immersion process so items cannot be wrapped during the sterilization process. In addition, items may need to be rinsed after the process so sterility is not maintained in the rinsing, drying, and storage phases. Therefore, this method of sterilization is used only when an item cannot be sterilized in any other manner.

Question 28

Cleaning process

Answer 28

Clean from least soiled (outside pt zone) to most soiled (pt zone) and then from high to low. Clean to dirty, high to low

Question 29

Types of tissue consider at high risk for CJD include

Answer 29

Tissues known to be highly infectious include brain, dura matter, pituitary tissue spinal cord and eye; ----- tissues with LOW infectivity include lung, liver, kidney, spleen, lymph and CSF

Question 30

correct storage to maintain sterility of reprocessed items

Answer 30

*Items should be stored at least 18 inches below the ceiling and 8-10 inches above the floor. Storage should be at least two inches from the wall and if a rack is used then it should have a solid bottom to avoid contamination of items from dust on the floor *The room must be positive pressure with a temperature of approximately 75°F, with a relative humidity not to exceed 70 percent

Question 31

Ultrasonic cleaners are used for:

Answer 31

Fine cleaning of instruments Rationale: Ultrasonic cleaners use sound waves to create bubbles that disrupt small particles that may exist in hard-to-clean places on instruments. Ultrasonic cleaners may be used after initial cleaning that removes all visible and accessible soiling is carried out and before final disinfection or sterilization, following manufacturer’s recommendations

Question 32

CDC recommends that endoscopy-associated infections be reported

Answer 32

to the person responsible for infection prevention at the facility; the physician responsible for the care of the patient; the appropriate public health agency (which is the FDA or CDC); and the manufacturer(s) of the endoscope, disinfectant/sterilant, and automated endoscope washer-disinfector (if used).

Question 33

Types of sterilitzation

Answer 33

* various types of steam sterilizers *gas sterilizers including those that use ethylene oxide gas, ozone, and hydrogen peroxide gas or vapor *liquid immersion in chemical sterilants. Sterilization of instruments results in the instruments being free of all microbes, including spores.

Question 34

type of indicators is most accurate for assessing whether surgical instruments have been processed correctly in a steam sterilization cycle

Answer 34

Biological indicator Rationale: A biological indicator is the only method of assuring that a steam sterilizer has reached the correct conditions to ensure sterility of products. Use of a biological indicator provides reliable, qualitative evidence that all sporeforming organisms have been inactivated during the sterilization cycle.