Recommendations by the Quality Task Group

[10] "Flash Sterilisation"

Flash sterilisation continues to be a topical issue or, possibly due to publication of the standardisation drafts for small steam sterilisers (prEN 13060, Part 1-4), it is eliciting keen interest once again and giving rise to many questions in sterile supply departments. Some of these recurring queries have induced the Quality Task Group to focus on the subject.

Open sterilisation of non-wrapped, individual, non-porous devices using a quick programme is known in many places as "FLASH STERILISATION". This expression is found neither in leading medical dictionaries nor in the standards governing sterilisation. Most likely, it was coined in the everyday operating theatre (OR) setting, since the instruments are sterilised in a split second.

The sequence of a quick programme is as follows: evacuate once (prevacuum), provide for steam penetration and heat to 134 °C, 3 minutes sterilisation time followed by a short drying time. A programme cycle takes about 15 minutes. Even today, such a process is being used in small steam sterilisers in OR departments and outpatient centres outside the sterile supply department.

The risk of RECONTAMINATION after the "flash sterilisation" is very great. In the opinion of T. Miorini and V. Buchrieser, on completion of the quick programme the non-wrapped medical device must be viewed as being non-sterile immediately after opening the steriliser door (cf. Small Steam Sterilisers in the Light of Standardisation Drafts, Central Service 1999, 7 (4): 240-247.).

Pursuant to the directive Hospital Infection and Prevention of Infection of the Robert Koch Institute (RKI), recontamination of the medical device must be ruled out after PROCESSING until the time of use. In annex 7.1, Performing Sterilisation, it states that the device to be sterilised must be suitably packed after cleaning and disinfection. Wrapped articles remain sterile after sterilisation until the time of use provided that they are properly stored, transported and removed under aseptic conditions. However, use of packaging precludes open sterilisation using a quick programme.

The proof of successful cleaning, disinfection and sterilisation of medical devices stipulated in Section 4 of the Medical Devices Operator Ordinance (MPBetreibV) cannot be furnished if a medical device is openly sterilised, i.e. in a non-wrapped state. It is hardly or not at all possible to reliably rule out recontamination of the sterilised, non-wrapped device during transportation to the place of use. Nor is it possible to formulate procedural instructions for transportation to rule out recontamination of the sterilised devices.

To be borne in mind additionally is that the SAL of 10^-6 (only one in 1 million microbes is allowed to survive) specified in EN 556 can be achieved only if a contaminated device is properly cleaned and disinfected before sterilisation. This excludes for instance cleaning of the device under running water since this method would not at all provide for adequate microbial reduction.

Heat-sensitive solid medical devices that might lend themselves to open sterilisation using a quick programme should undergo automated cleaning and thermal disinfection before sterilisation, since this represents the safest method of microbial reduction. This cleaning and disinfection process alone takes about 45 - 60 minutes.

The TIME SAVING advantage is thus already abrogated by correct cleaning and disinfection of a medical device.

In the everyday CSSD setting, "flash sterilisation" of instrument sets between two operations is a problem frequently encountered. Processing of instrument sets between two operations is governed by the same rules as those applying to processing of an individual instrument. It must also be borne in mind that instruments must be checked, overhauled and packed before sterilisation.

From the time periods given above for processing in line with quality assurance dictates it can be easily deduced that the entire processing procedure takes more time than that generally available between two scheduled operations.

Section 4 of the Medical Devices Operator Ordinance MPBetreibV stipulates that processing of medical devices be carried out by personnel who have the requisite expertise. This rules out performing processing outside the CSSD in hospitals.

"Flash sterilisers" are mainly installed in the corridors of surgical departments and are not operated by CSSD staff. Here the question arises as to whether the OR personnel are aware that by engaging in "flash sterilisation" in the OR department they are exposing to avoidable risks the patients entrusted to their care in the OR.

Small steam sterilisers pursuant to prEN 13060 are apparatuses whose capacity is less than 1 StU. prEN 13060 distinguishes three different types of apparatus:

• type B for sterilisation of wrapped, solid, hollow and porous items
• type N for sterilisation of non-wrapped, solid devices
• type S for sterilisation of devices specified by the steriliser manufacturer

In the preface to prEN 13060 it is stated that small sterilisers are intended for use in doctors� surgeries, dental surgeries and veterinary surgeries. The contents of prEN 13060 are still being presently discussed in the standardisation committee. The provisional standard makes no reference to use in hospitals.

Recommendation by the Quality Task Group of the German Society for Sterile Supply (DGSV) for "flash sterilisation"

"Flash sterilisation" of medical devices in the hospital should not be conducted for the following reasons:

• open sterilisation of medical devices is not permitted as per guideline 7/7.1 of the RKI
• proof of processing of medical devices in line with quality assurance dictates as stipulated by the German Medical Devices Act (MPG) and the Operator Ordinance cannot be furnished
• the SAL specified in EN 556 can be achieved only by cleaning and disinfection of the medical devices prior to sterilisation
• "flash sterilisation" in surgical departments must be viewed as being a relic from the past and does not reflect the current stock of medical knowledge or the state of the art
• the OR staff are often not deemed to be experts in the processing of medical devices.

Sterilisation of a medical device must be seen as one step in the processing circuit. Processing of medical devices should be carried out in the sterile supply department by personnel specially trained for this task.

The CSSD staff who have in-depth knowledge of processing of medical devices should, if necessary, make the surgeons and OR personnel aware of the risks posed by "flash sterilisation" and propose organisational alternatives.

The time actually needed for processing and the number of instrument sets available should be taken into account when planning an operation. This would obviate the need for "flash sterilisation". With good communication and cooperation between OR and CSSD, instrument sets can, if necessary, be cleaned, disinfected and sterilised within around 2 hours, while furnishing proof of compliance with standards and quality assurance dictates.

As already pointed out in the first part of this recommendation, the term "flash sterilisation" does not really exist at all. Hence we need not delete any words from dictionaries but rather from our heads.

What is meant by "flash sterilisation"?

"FLASH STERILISATION" denotes open sterilisation of non-wrapped, solid, individual devices.

RECONTAMINATION of sterilised devices can be ruled out until the time of use only by the packaging. Hence the risk of recontamination after "flash sterilisation" is very great.

PROCESSING of a medical device comprises cleaning, disinfection, functional testing, packing and sterilisation. This proper sequence is not observed in "flash sterilisation".

TIME SAVING conferred by the quick programme is minimal, since it is not possible to correctly process a medical device, including cleaning and disinfection, in 15 - 20 minutes.

MPBetreibV and standardisation drafts

MPBetreibV stipulates that processing of medical devices be carried out by personnel who have the requisite expertise.

prEN 13060 is the provisional version of the standard for small steam sterilisers. It makes no provision for use in hospitals.

Recommendation by the Quality Task Group