Decontamination and Disinfection

Question 1

Define cleaning

Answer 1

Physical removal of microbes (including prions) but not necessarily killing them

Question 2

Define disinfection

Answer 2

• Reduction of the number of viable microorganisms but may not inactivate some microbial agents, such as certain viruses and bacterial spores
• It should make the disinfected object safe to handle

Question 3

Define sterilisation

Answer 3

Killing and removal of all microorganisms including bacterial spores

Question 4

How should we decontaminate high risk equipment?

Answer 4

Sterilisation or single use item

Question 5

How should we decontaminate medium risk equipment?

Answer 5

• Preferably sterilisation
  OR
• High level disinfection

Question 6

How should we decontaminate low risk equipment?

Answer 6

Disinfection

Question 7

What does HTM01-05 state about single use instruments?

Answer 7

Single use items should never be reused

Question 8

What does HTM01-05 state about the number of hand washing and decontamination sinks in decontamination units?

Answer 8

• 1 Hand washing sink

- 2 Instrument decontamination sinks

Question 9

What does HTM01-05 state about wrapped instrument storage?

Answer 9

Wrapped instruments may be stored up to 1 year

Question 10

List some modes of transmission for microbes (5)

Answer 10

• Direct contact
• Indirect contact
• Inhalation
• Ingestion
• Inoculation

Question 11

What does HTM01-05 state about storage of unwrapped instruments? (2)

Compare storage in clinical vs non clinical areas

Answer 11

• Maximum storage in clinical area is 1 day

- Maximum storage in non-clinical area is 1 week

Question 12

What does HTM01-05 require immunisation from?

Answer 12

• HBV

- Tetanus

Question 13

Describe a single decontamination room (5)

Answer 13

• Dirty zone
• Clean zone
• Separate wash hand basin and storage for PPE in both zones
• Air flow from clean to dirty
• Instruments flow from dirty to clean

Question 14

What would you find in a dirty zone of a single decontamination room? (5)

Answer 14

• Washing sink
• Rinsing sink
• Ultrasonic bath
• Preliminary inspection area
• Thermal washer disinfection

Question 15

What would you find in a clean zone of a single decontamination room? (4)

Answer 15

• Inspection area
• Steriliser
• Package area
• Storage area

Question 16

What are the applications of high risk contamination instruments? (4)

Answer 16

• Penetrate soft tissue
• Contact bone
• Enter normally sterile tissues or blood stream
• Close contact with break in skin or mucous membrane

Question 17

What are the applications of medium risk contamination instruments? (3)

Answer 17

• Contact non-intact skin
• Mucous membrane
• Body fluid

Question 18

What are the applications of low risk contamination instruments? (2)

Answer 18

• In contact with intact skin

- Does not come in contact with patient

Question 19

Describe a double decontamination room (5)

Answer 19

• Dirty room
• Clean room
• Separate wash hand basin and storage for PPE in both zones
• Air flow from clean to dirty
• Instruments flow from dirty to clean

Question 20

What is the aim of cleaning?

What cannot be carried out effectively if instruments are not clean?

Answer 20

• Decrease the bacterial load by thousand fold

- If the instruments are not clean, they cannot be sterilised effectively

Question 21

Name 2 types of automated cleaning?

Answer 21

• Ultrasonic bath

- Thermal washer disinfector

Question 22

Why is it important to avoid letting instruments dry out?

Answer 22

Blood is corrosive to stainless steel therefore, do not let instrument dry out

Question 23

What type of detergents are recommended in manual cleaning?

Answer 23

Non-foaming detergent

Question 24

What type of brushes are recommended in manual cleaning?

Answer 24

Use long handle soft nylon brushes

Question 25

What temperature is recommended in manual cleaning?

Answer 25

Water temperature should not be more than 45°C to avoid protein coagulation

Question 26

What type of drying instrument is recommended in manual cleaning?

Answer 26

Use disposable lint free cloth (paper towel) to dry instrument

Question 27

What type of instruments can be put in an ultrasonic bath?

Answer 27

For metal instrument not plastic (absorb ultrasonic energy)

Question 28

Does an ultrasonic bath disinfect instruments?

Answer 28

Only clean but does not disinfect instruments

Question 29

Why is the thermal washer disinfector the preferred cleaning method? (2)

Answer 29

• More efficient in reducing bacterial load during pre- sterilisation cleaning
• Enhanced staff safety as handling sharp contaminated instruments is significantly reduced

Question 30

Why should Gluteraldehide not be used as a chemical disinfectant?

Answer 30

Irritant and sensitise the skin, eyes and respiratory tract

Question 31

Why should Chlorhexidine not be used as a chemical disinfectant?

Answer 31

Chlorhexidine binds to protein and makes them more adherent to the instrument

Question 32

What are the recommended chemical disinfectant agents? (2)

Answer 32

• Peracetic acid

- Chlorine releasing agents

Question 33

Sterilisers N cycle;

Air removal?
Suitable for sterilising?
Not suitable for sterilising? (5)

Answer 33

• Non-vacuum
• Solid
• Wrapped devices
• Hollow devices
• Devices with lumen
• Heat labile
• Single use item

Question 34

Sterilisers B cycle;

Air removal?
Suitable for sterilising?
Not suitable for sterilising? (2)

Answer 34

• Vacuum steriliser
• Most instruments
• Heat labile
• Single use item

Question 35

Sterilisers S cycle;

Air removal?
Suitable for sterilising?
Not suitable for sterilising? (2)

Answer 35

• Vacuum steriliser
• Load specified by manufacturers
• Heat labile
• Single use item