Automatic Washer-Disinfectors

Question 1

What stages are involved in AWD’s? and what is involved in each?

Answer 1

There is fresh water, used for each individual stage.
Flush/Pre-Wash
–This stage saturates the contamination and removes gross contamination (large parts of biological matter removed)
Main Wash
–This stage is supplemented by detergent to more effectively remove biological matter
Rinse
– This stage removes any remaining residue, biological or chemical before disinfection
Thermal Disinfection
–This stage actively kills microorganisms with the use of heated water
Drying
–This stage uses hot air to remove any remaining moisture from the surface of the instruments

Question 2

What temperature does the Flush/Pre-wash stage need to be?

Answer 2

Less than 35 degrees

Question 3

What temperature does the Main Wash stage need to be?

Answer 3

Temperature dependent on chemical used for process

Question 4

What temperature does the Rinse stage need to be?

Answer 4

Less than 65 degrees

Question 5

What temperature does the Thermal Disinfection stage need to be?
How long for?

Answer 5

Must be between 90-95 degrees
For a minimum of 1 minute

Question 6

What temperature does the Drying stage need to be?

Answer 6

Has no specified temperature but generally 100 degrees (hot air)

Question 7

What type of biological matter is removed in this stage?

Answer 7

Proteins or prion (vCJD)

Question 8

What are the Daily Checks for AWDs?

Answer 8

Check that the spray arms spin freely without obstruction
Check the spray jets (on the spray arms) are not blocked
Make sure there is no debris on the strainer/filter, and that there are no parts of instruments or any other potential blockage’s
Check the condition of the door seal and wipe and clean if necessary
Verify there is enough chemical in the reservoir
Read the disinfection temperature of the first cycle every day (Automated Control Test (ACT))

Question 9

What are the Loading Requirements of AWDs?

Answer 9

The available load carrier/basket furniture must be used
Clip trays must be used and positioned correctly
No overlapping or shadowing of equipment
Hinged instruments must be opened at the hinge
All assemblies should be dismantled beforehand

Question 10

What step do you need to carry out after the WD process is finished?

Answer 10

Inspection
All instrumentation must be inspected for damage or to see if there is still contamination present
Use an illuminated magnifier for this

Question 11

Following inspection, if instrumentation is still contaminated what are the next steps? What happens after these additional steps?

Answer 11

Ultrasonic bath
Manually cleaned
After these steps have been carried out, it must be processed back through the WD

Question 12

What step is after the WD?

Answer 12

Sterilisation

Question 13

Why do proteins and prions (vCJD) have to be removed at this stage?

Answer 13

Because when it reaches the sterilisation stage it cannot be neutralised

Question 14

What must be carried out before beginning the decontamination process? (PPE)

Answer 14

Hand hygiene
An apron
Face shield
Gloves

Question 15

What are the stages in AWDs?

Answer 15

Flush/Prewash
Main Wash
Rinse
Thermal Disinfection
Drying