Week 6

Question 1

Define cleaning

Answer 1

Removal of organic material (body fluids, tissue, biofilm), removes the nutrient source and coating/protective barrier over pathogens
- in contact with intact skin only e.g. stethoscope

Question 2

Define disinfection

Answer 2

Destruction or removal of infectious agents to an acceptable level (not sporicidal)
- in contact with non-intact skin and or mucous membranes, e.g. nasal swab

Question 3

Define sterilisation

Answer 3

Destruction/removal of all living agents (including spores)
- in contact with sterile body cavities/tissues e.g. catheter

Question 4

What are the 3 categories that medical items used in patient care are classified as?

Answer 4

• non-critical (cleaning)
• semi-critical (semi-critical)
• critical (critical)

Question 5

Examples of physical control methods and when they are used

Answer 5

STEAM (steam under pressure)
- sterilization
- used for non-heat-sensitive equipment

TEMPERATURE EXTREMES (<4c and >100c, - disinfecting
- food/drug storage, dry heat incineration
for clinical waste

IRRADIATION
- non-ionizing (UV) disinfecting used for
water, biosafety cabinets surfaces
- ionizing (gamma) used for medical
plastics & syringes

FILTRATION (0.2 bacteria, 0.02 viruses)
- fluids containing dissolved solutes

Question 6

Examples of chemical control methods and when they are used

Answer 6

ALCOHOLS (60-90%)
- hand hygiene, surface disinfection

QUATERNARY AMMONIUM COMPOUNDS
- surface disinfection (not sporicidal)
- pine O clean
- Dettol
- disinfecting, not sporicidal

PHENOLICS
- toxic not frequently used
- surface disinfection

HYDROGEN PEROXIDE
- 2-5%
- skin antisepsis (disinfection), gas under
vacuum (sterilisation)

HALOGENS
- sodium hypochlorite (bleach) 1-10%,
iodine 7%, chlorhexidine 2-4%
- corrosive and oxidizing
- skin antisepsis, hand hygiene

ALDEHYDES
- formalin, glutaraldehyde
- high level disinfection for equipment (endoscopes)