How should you clean instruments prior to sterilisation?
- Wash instruments in cold or lukewarm water with a detergent to remove blood, fat or tissue.
- Use a soft brush, taking care not to catch the bristles in the joints or dull the delicate edges of fine instruments.
- enzymatic cleaner is excellent for removing gross material.
- Rinse in hot water.
- Dry by blotting the instruments between two towels, or drying in an oven.
- the use of lubricant milk is not recommended as it can trap pathogens under the layer of grease
Most of the deterioration in instruments comes from..
improper cleaning and abuse.
Use as pliers, screwdrivers, hammers and scissors for cutting bandages and trimming finger nails causes irreparable damage.
Is blood corrosive to stainless steel?
wash instruments asap after use
If instruments are left for a longer period of time between use and washing, you should...
soak them in cold water before cleaning
Are Chlorhexidine and povidone iodine suitable for cleaning instruments?
not suitable to clean instruments and can cause pitting and eventual damage to instruments
What pH should an instrument cleaner be?
When cleaning an instrument, what should you check?
- put aside any instrument that seems broken or disfigured.
- Make sure ratchets work correctly
- that instruments can grip properly: use a gauze swab to test this.
- Check the tension on the ratchets by engaging the first notch and tapping the shaft. If they spring open, they are unreliable.
- Check the alignment and angle of the jaws of instruments.
How should you store instruments that have a ratchet?
ratchets open or on the first notch.
Storage of instruments with their ratchets fully closed will eventually lead to metal fatigue and loss of function.
How should you clean linen theatre drapes after use?
- Soak immediately in cold water with a biological stain remover.
- Rinse away blood
- Remove any other extraneous material, eg, fat, suture material and hair.
- Wash drapes and gowns in a washing machine. Do not wash drapes and gowns along with dog/cat bedding and towels.
- Hang out to dry on a clothesline in the sun if possible
- After laundering, check for any remaining hair and remove it
- check for holes (not the fenestrated drapes!), frayed edges and loose threads prior to packaging. Discard damaged drapes.
How should you fold a surgical gown and drapes?
- so surgeon/assitant does not touch the outside
- Fold them lengthwise, outside-in (gowns)
- with the tapes on top of the bundle.
- The bundle, with hand towel on top, is wrapped in the same fashion as for drapes.
List three methods of cold sterilisation
Radiation (gamma) Sterilisation
widely used to sterilise foil wrapped items such as scalpel blades and suture materials. It is also used for rubber and plastic items such as syringes and endotracheal tubes.
Ethylene oxide gas is used in industry to sterilise heat and moisture sensitive items which cannot withstand temperatures greater than 60° C.
Filters are not sterilising agents, but are used to remove micro-organisms an particles from liquids and gases, so rendering them sterile. Filtration methods are used to purify large quantities of water and air.
List two methods of heat sterilisation
requires prolonged periods of exposure at high temperatures (about 4 hours at 160°C in a hot air oven). Used for items such as powders and oils that would be damaged by moist heat. This method is not widely used any more.
Autoclaving, steam under pressure, is used in veterinary practices for sterilising surgical instruments, gowns, drapes, swabs, most rubber articles, glassware and some plastic goods.
Describe the principles of autoclaving
- At normal atmospheric pressure (sea level), the highest temperature produced by boiling water is 100°C. Destruction of heat resistant micro-organisms will not be achieved at this temperature. However, if the pressure around the boiling water is increased 15 psi above normal atmospheric pressure, the temperature of the boiling water will be increased to 121°C. At this temperature all micro-organisms including heat-resistant spores will be destroyed.
- Sterilisation begins as the steam enters the sterilising chamber and condenses on the colder surfaces. This condensation of water produces heat which penetrates the packaged items from the outside through to the centre. Moisture increases the penetrability of the heat, so it is important that the items are arranged to facilitate this.
- After the specified time has elapsed, the steam is allowed to escape from the chamber, which is followed by a fall in temperature. The door should not be opened until the pressure gauge has dropped to zero and the temperature gauge is below 100°C.
- The higher the temperature and pressure of the steam, the shorter the length of time required for sterilisation to occur
describe Vertical pressure cookers
- have an air vent at the top which is manually closed after all the air has been evacuated.
- can be a disadvantage, as some air may remain trapped under the steam and therefore cause a lower temperature to be reached in this area.
- manually operated steriliser, human error can influence the effectiveness of sterilisation.
- no automatic drying cycle, so items may be damp at the end of the cycle.
- packs are fully dried before storing.
describe Horizontal or downward displacement autoclaves
- most common in veterinary practice.
- electrical units and can be fully or semi-automatic.
- steam outlet at the top and the air outlet at the bottom provide more efficient operation, as air is driven out by downward displacement
describe Steam Pulsing systems
- cycle time is generally shorter than downward displacement systems.
- are cheaper than pre-vacuum sterilisers.
- Steam is actively pulsed into the chamber to reach a given pressure and then the chamber is vented to a minimal pressure before the next pulse.
describe Vacuum assisted or pre-vacuum autoclaves
- air is evacuated rapidly from the sterilising chamber at the beginning of the cycle creating a vacuum, so steam penetration and sterilising occur very rapidly.
- A second vacuum cycle removes moisture after sterilisation, facilitating drying of the load
- have a large capacity and are fully automated.
- are often connected to a central steam boiler.
All autoclaves have the following features:
- Source of saturated steam under pressure,
- Pressure gauge indicating the pressure within
- Temperature gauge
- Safety valve to prevent explosion should the pressure become too high
- Method of removing air
- Shut-off valve to prevent the escape of steam once the air has been removed
- Valve to release steam at the end of sterilisation
- A door seal
- Safety locking mechanism for the door
When can you open an autoclave door?
when chamber pressure reaches zero, and the chamber temperature is below 100°C.
Effective sterilisation will only occur if the following steps are carried out:
- Equipment to be sterilised is cleaned and dried
- Equipment is wrapped/ packed
- Items are loaded into the autoclave
- Sterilisation cycle is started
- Load is dried after sterilisation
- Sterilised items are stored appropriately
How should you prepare instruments for sterilisation?
1. Clean the instruments thoroughly.
2. Place suitable wrapping on table or tray then arrange instruments into identical groups
3. Secure the groups, using a towel clamp through one side of the handle of each instrument.
4. Make sure all instruments are not locked
5. Pack instruments together neatly in the centre of the wrapping material with a sterilisation indicator strip.
6. If required, add swabs and suture needles.
7. Wrap instruments in concertina fashion.
8. Place in autoclave bag or wrap with autoclave paper
9. Label with a Sharpie the type of kit, the date and intitals of person packing.
Name some packaging materials for sterilisation