EFHSS Questions and Answers - Question Q00148

Dear Sirs,

Please tell me about the advantage of Double Door compare with Single Door Sterilizer. Thank you for your Kindly

Niece Cole

Dear,

As well as there has to be a separation between the dirty and the clean area of the CSSD, to prevent recontamination of the washed and desinfected products, also clean and sterile zone must be separated to avoid:

• mixing of non sterile and sterile items and thus preventing errors,
• recontamination of the sterile goods.

Direct traffic between the different zones is not allowed. This can best be realised by using double door washer-desinfectors and double door autoclaves as separation.

Kind regards,
Wim Renders

Niece!

you pose a very controversial subject and this very question can send users and engineers into an infinite spin when its discussed.
Wim is correct in stating that there is a logical separation when the Washer/disinfector is a two door system, as the decontamination area or pre-wash can be highly decontaminated and adds to a high bio-burden when not separated from the packing area. Observing the two door system for Sterilisers is a separate and different scenario. An engineer sees the two door system as double trouble syndrome, (maintenance and routine testing) Look at two door sterilisers.

• two doors
• two door gaskets
• two sets of interlocks
• two p/n rams (vertical lift)
• increased possibility of door failures
• increased possibility of integrity of chamber being compromised
• full access to service and ergonomic testing restricted

In summary if the steriliser is correctly validated the door should not open until the cycle is comlpete and sterilisation is assured. So if single or double door this assured condition should not change, By using two doors does not guarantee sterilisation because of an automatic opened door on the clean side (cooling side). The process of sterilisation is well understood and the attainment of sterilisation can normally be confirmed by simple bur verified physical measurements. The process is not reinforced or more assured by the two door system (sterilzers) but maintenance may be compromised during the total life cycle of the sterilzer.

This issue should not be a point of discussion. As soon as there is a certain risk of mixing sterilised goods with not sterilised goods this should be avoided! (please be aware that Murphy's law also is applicable for the work done at a CSSD)
There is no simpler, cheaper and safer solution than to use pass-trough sterilisers. Of course the points concerning costs and engineering mentioned by Hugh O'Conner do (partly) count. However if you compare the costs involved over the total life cycle (including exploitation costs) you will find you have to pay a very low insurance contribution to avoid mistakes or accidents. So if the architectural space is available another solution than pass-trough should not be considered.

If you have any further questions please do not hesitate to contact me,

Best Regards.
Henk Ras

Sanamij B.V.
http://www.sanamij.com

Niece,

Firstly I have to support wholeheartedly the points that Hugh O'Connor has made as maintenance of your sterilizers must surely be a priority and if that can be made easier in any way it should be considered. Do not forget that as a manager of a department you want to ensure that as little problems as possible occur especially with machinery that you are heavily dependant on.

My department is only opened two years and we have single door sterilizers and the system works very well. We have never had any problems with sterile and non sterile goods getting mixed up. Of course I think ultimately the assurance that this never happens comes down only to one thing and that is having in place a quality system that is regularly reviewed and audited. Hugh states that the presence of double doors does not give an assurance of sterility or that sterile and non sterile goods will not get mixed up and he is absolutely correct.

Staff need to be trained to identify the strengths and weaknesses of systems that are in place and to stick strictly to departmental policies and procedures. Of course human error is unavoidable but there are plenty of precautions that should take place before any non sterile item is used on a patient. We have a computerised bar-coding system in place and all of our items are scanned before and after sterilisation. They are then taken directly to the sterile store where they must be scanned again before leaving the department. Any item that has not been scanned in the sterilizer room will automatically be rejected by the computer as being unready to leave the department. This precaution alone cannot prevent mistakes but in conjunction with others it helps control the quality system which is in place.

There are positives and negatives to both sides of argument on single or double door sterilizers but I don't think it is as simple as stating that double doors will prevent sterile and non sterile goods getting mixed up!

Aisling Bonner
HSDU Manager
Altnagelvin Hospital
Derry City
Northern Ireland.

A further aspect pro Double Door Sterilizer.

The workflow from the cleaning area to sterile storage is a one-way street. Be unloading sterile goods in the packaging area is actually on step back. The time immediately after opening the sterilizer door at the end of the program is generally a most critical time for maintaining sterility. Items should not be moved or touched until they have cooled down to room temperature.
Cool-down should occur in a zone, free of traffic and without strong air movements. Yet the packaging or preparation area is usually an area where lots of activities/traffic is going on. Air that enters the sterilizer when the door is open can carry microorganisms that could contaminate the packs. CSSD's planned for construction in the future must conform the standards of "Good Manufacturing Practices" this includes pass-through sterilizers as strict separation.

Josy Holdener

To follow up on what has been said about loading and unloading of sterilizers in the packing area. I believe that these functions should only take place in a separate area namely the sterilizer or autoclave room. To have sterilizers attached to the end of the packing room would I think only put extra pressure on trying to control the status of class L which is what all packing areas are supposed to conform to.

All trays once packaged can be passed to the autoclave room via a hatch or pass through area with interlocking double doors. This allows for separation of the packaging area and the sterilizing area. The cooling down of trays once sterilized can be done in a separate area within the sterilizer or autoclave room before they are finally transported to the sterile store.

This is the system we have been using quite successfully for the last few years.

Aisling Bonner