Disinfection & Sterilisation Flashcards
Chain of infection? Process?
- Susceptible host
- Infectious agent
- Reservoir
- Portal of exit
- Mode of transmission
- Portal of entry
Decontamination cycle? Process?
- Use
- Transport
- Cleaning (acquisition)
- Disinfection
- Inspection
- Packaging (disposed)
- Sterilisation
- Transport
- Storage
Decontamination? Definition?
- The combination of processes including cleaning, disinfection and/or sterilisation, used to render a re-usable item safe for further use
Cleaning? Definition?
- The process that physically removes soiling including large numbers of micro-organisms and the organic material on which they thrive
High potential clinical contact surfaces? Examples?
- Handles
- Head of chair
- Light head
- Spit bucket
- Chair buttons
- Chair
- Chair instruments
Disinfection? Definition?
- Reduction in the number of viable micro-organisms on a product to a level previously specified as appropriate for its intended further handling or use
Inactivation of microorganisms? Types of drugs?
- cidal: kill organism
- static: reduction in repro
Chemical disinfection? Mechanism and example?
Disrupt cell mem: - alcohol and detergents Mod of prots: - chlorine, iodine, heavy metas, H202, formaldehyde and strong acids/alkalis Mod of nucelic acids: - dyes (thermal disinfection: washer)
Safety of disinfection agents? What to consider?
- Toxicity
- Shelf life
- Ease of use
Sterilisation? Definition?
- The process to render a product sterile
What is sterile? Definition?
- Subject to a validated sterilisation process so there is less than 1 x 10-6 probability of a surviving organism
Sterilisation? Types and examples?
- Items must be cleaned, rinsed and dried before going into the autoclave. - Items must not be touching
- Non Vacuum: bench top steam steriliser; gravity displacmement for unwrapped instruments
- Vacuum: porous load steriliser; forced air removal for porous loads and wrapped instruments
Methods of sterilisation? Examples?
- Heat
- Chemical
- Radiation
- Filtration
Sterilisation? Heat? Types and mechanism?
- Destruction of micro-organisms by denaturing proteins
- Dry/Moist or Pasteurisation
Dry heat? Process?
- Requires 180C held for 2 hrs
- mostly for glassware
Moist heat? Process?
- Steam
- Lower temp than dry hear
Autoclave: - 134C for 3 mins
- Steam enters and leaves via vent out to waste line
Pasteurisation?
- For milk
- 62C for 30 mins
- not sterile
Chemical sterilisation? Characteristics?
- Some instruments/plastics would be damaged by autoclaving
- Chemical gas is an alternative
- Ethylene oxide most common
- Alkylates proteins and nucleic acids
Radiation sterilisation? Characteristics and types?
UV radiation:
- Disrupts DNA replication
- Suitable for hospital environment
- x10 higher dose to kill spores
X-ray:
- Higher energy and penetrating power than UV
- Produces free radicals which kill organisms
- Kills vegetative cells readily but spores are more resistant
- Useful for heat sensitive items
Filtration sterilisation? Characteristics?
Membrane filters
- Air e.g. in hospital theatres.
- Liquids – IV infusions
Decontamination risk categories? High, medium and low? Recommendation of process?
High: STERILISATION
- penetrate skin, enter sterile body or contact ulcerated mucous mem
Medium: DISINFECTION
- contact intact mucous mem or non-intact skin
Low: CLEANING
- intact skin or not with patient
Local decontamination unit? Flow chart?
- Clean and dirty area
- Cleaning machines
- Clean and dirty flow of instruments (no crossover)
RA for PPE? Flow chart?
No blood:
- No PPE
Fluids/low splash:
- Gloves and apron
Fluids/high splash
- everything
Hand hygiene? Key moments?
Clean your hands before examining a patient
• Clean your hands immediately before any aseptic technique
• Clean your hands immediately after exposure to risk body fluids
• Clean your hands after touching a patient
• Clean your hands after touching any object or furniture in the patient’s surroundings when leaving
Antiseptic solutions? Examples?
Chlorhexidinegluconate (Hibiscrub)
• Intermediate range of antimicrobial activity
• Slow-acting but persistent chemical activity
• Less irritating to skin
Idophors(Betadine)
• Wide range of antimicrobial activity
• Persistent chemical activity
• Irritating to skin
