Steam

Question 1

why do we use steam

Answer 1

• Steam carries a massive amount of energy
• It is a non-toxic component in the sterilisation process
• For certain applications it can be recondensed and used again
• The main ingredient is water which is readily available
• There is no waste product except water

Question 2

steam use in sterilisaation

Answer 2

essential that we use purified water

This has had organics, minerals and bacterial presence removed or filtered from it beforehand

Question 3

volume steam Vs water

Answer 3

excess of a thousand times greater

• This creates a huge amount of pressure within small confined spaces

very useful to us in regards to sterilisation we can flood the chamber with steam from a very small amount of water.

• The high pressure also helps with the permeability of steam

Question 4

types of steriliser (3)

Answer 4

• Type - N
• Type - B
• type -S

Question 5

type-N

Answer 5

• The most basic process of the sterilisers also referred to as a Gravity Displacement Steriliser

Question 6

type- B

Answer 6

• This has the most robust processing cycle of all the equipment. Also referred to as a Vacuum Capable or Porous Load Steriliser

Question 7

type - S

Answer 7

• This machine is generally a specialised piece of equipment, used for a specific purpose e.g. sterilising dental hand pieces

Question 8

air in steam sterilisers

Answer 8

Air does not behave the same way as steam

• It can not be heated, or maintain temperature the same way that steam can.

always a lower temperature than the steam surrounding it.

If it is in contact with air it is not contacting steam.

• This means anything that the air is in contact with might not achieve its sterilisation temperature for the minimum required time

Question 9

Type-N steriliser

use

Answer 9

heats water in the chamber and as it turns to steam it passively forces the air from the chamber.

• This process isn’t entirely efficient and can leave pockets of air within the chamber.
  
  • not favourable
• cycle isn’t entirely efficient
• it is recommended that we only process
  
  • “rigid steel instrumentation with no pockets channels or lumens”
  • do not process “wrapped instrumentation”
• It must achieve a temperature of between 134 – 137 degrees Celsius
  
  • And must maintain this for a minimum stage hold time of 3 minutes

After the process the instrumentation has only “been sterilised” It may not be sterile at the point of use

Question 10

Type-B steriliser

use

Answer 10

The cycle starts by removing all of the air from the chamber creating a “negative pressure”

• using a vacuum pump

As the steam rushes in it expands into the chamber and is forced to contact all surfaces due to the vacuum effect, penetrating wrappings as well

It must achieve the same temperature of 134 – 137 degrees Celsius

• And hold this for the same stage time of 3 minutes

It then has a drying stage at the end to remove any remaining moisture

Because of the vacuum process within this machine we can process “wrapped, channelled and lumened instruments”

• We can also process porous items such as cotton wool swabs

Question 11

Type-S Steriliser

use

Answer 11

The process within this equipment is different.

• This piece of equipment also washes and lubricates hand pieces that are being processed as well as sterilising them.

It has a vacuum cycle but does not process wrapped instruments

It still achieves the same temperature, 134 – 137 degrees Celsius

• And has the same stage hold time of 3 minutes.

It can only be used for the equipment it is designed to process

• manufacturers recommendations must be followed

Question 12

Type-N steriliser

limitation

Answer 12

we cannot process wrapped instrumentation there is a danger of re-contamination before the instrumentation can be used, it has only been sterilised

Question 13

Type - B steriliser

benefit

Answer 13

Because we are able to process wrapped instrumentation, providing the wrapping stays intact, the instrumentation will be sterile at the point of use and can be stored for long periods of time

Question 14

Type S steriliser

limitation

Answer 14

This machine is only for processing specific items such as hand pieces.

It still achieves the same temperature for the same amount of time though.

• Manufacturers recommendations should be followed for loading and operation of this equipment

Question 15

current guidance documents for sterilistion

Answer 15

• SHTM 2010, referencing BS EN 285 standard.

Question 16

regualtions for sterilisation provides us with

Answer 16

assurance that we have destroyed all “viable micro-orangisms”

only works if we have combined it with suitable cleaning and disinfection processes before

Question 17

time and temperture banding for sterilisation

Answer 17

time and temperature bandings are globally recognised as conditions required to achieve sterilisation.

• between 134 – 137 degrees Celsius
  
  • And must maintain this for a minimum stage hold time of 3 minutes