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Sterilization. Past and Future

by Tim Galekop

A lot of things have changed over the years in the sterilization area. The sterilization department has increasingly become much more important. The changes occurred, among others, in the area of organisation, packaging, and legislation. In the past CSSD staff members were considered the dishwashers of the operating room, or the CSSD was treated, as the "social workshop" of the hospital where employees were parked which were not fit for anything else. Today this department has become a highly technical unit with sophisticated requirement. In several European countries there are Sterilization Associations and special courses for sterilization managers and personnel. Thus, the CSSD has become the heart of the hospital, i.e. if it does not work, the OR can-not operate.

Back in the ninteenfifties or in the beginning of the sixties it was probable the UK who introduced the first CSSD (Central Sterilisation Supply Department) in Europe which was copied from the USA. The day to day practice at that time, however, was that every operating room did their own cleaning, disinfecting, packaging, sterilizing and storing.

It was also in the UK where in 1966 the first meetings took place between the Ministry of Health and the Medical Packaging Industry. This lead in 1967 to the first published TSS standards for Sterilization paper plain, Crêpe paper, and paper sterilization bags.

In March 1981 the Netherlands officially published the law for Medical Devices for hospitals. This was the first comprehensive law for hospitals.
In 1980 the Netherlands started with the Dutch norms for sterilization (RIVM), the first standards were officially published in 1984. (Steriliseren Steriliteit).
The Netherlands became a leading country in Sterilization certainly in Europe, but probable even on a global scale.
On 14th June 1993 European Council Directive 93/42/EEC was published concerning medical devices and the CEN standards to minimise the risks and optimise security for use and patient.

Nosocomial infections - implications for packaging

The first surgical operation took place in Babylon about 4000 years ago. In the 19th century, approximately 60% of the patients died of hospital fever.
Today we are still talking about infection control and the amount of postoperative infections, which do occur. Several figures have been published and it is shocking to see how much this all costs.
Some time ago a damning report on infections caught in English hospitals says they are killing 5,000 patients a year and are implicated in the deaths of another 15,000 people. The report criticises hospital managers and reveals wide differences in the amount trusts spend on infection control.
Similar reports have now been published in other European countries. In Belgium, 70,000 infections occurred and 2,800 patients died. In Germany, 640,000 hospital related infections were reported, with a death rate of 1 - 2 %. In the Netherlands, ± 5% of the patients who are hospitalised, meaning 80,000 people, get infected. About 2,600 people die. Huge costs are involved.
Not only the huge cost is important but also, of course, the human grief. The Dutch National Health Council stated, "A patient is taken into hospital to recover and not to get another illness".
Another problem is the resistance of bacteria against antibiotics and penicillin not yet taking about the new viruses or illnesses like Creutzfeldt-Jacob’s Disease, hepatitis, MRSA (Multi Resistant Staphylococcus aureus), AIDS, and SARS.
It was around 1881 that Robert Koch started the steam sterilisation followed in 1890 by the introduction of the Schimmelbush drum. This round steel drum was probably the first packaging system and had holes in the sides to allow steam to enter. A sliding steel band was closed directly after sterilising to cover the holes. Regrettably, in certain countries this drum is still used.
In ± 1930 textile was introduced as a sterilisation packaging material. At that time still in white. During the 2nd world war the colour changed to green. The reason for this was most likely that the textile industry had to produce textile for the army, so there was no white textile available.
About 5 years later the first developments on sterilisation paper started, which lead to the so-called Bripac sterilisation boxes.
It was around 1940 that Germany developed and introduced the aluminium containers followed in 1950 by the paper sterilisation bags.
10 years later the first heat-sealable peal pack pouches came onto the market. The advantage of this packaging system was that one could see what was packed and that an aseptic opening was possible.
In 1970 it was an American company called C.H.Dexter (now part of the Finish group Ahlstrom) who introduced the first nonwoven sheets of sterile barrier systems under the name Dextex.

Sterile barrier systems on their own will not prevent nosocomial infections from happening. However, the sterile barrier system, which is the minimum packaging configuration that maintains sterility of the package contents until aseptic presentation at the point of use, is one of the most important parts of sterilisation, after cleaning and disinfection. The advantage of single-use packaging materials is prevention of migration of microorganisms. It should by now be well known that conventional textile cannot be considered a bacterial barrier and is therefor not appropriate to be used as a sterilisation packaging material.
Single-use packaging systems offer maximum safety, sterility and efficiency.
After sterilisation a barrier is needed to protect the packed medical devices and to maintain sterility until the point at which they will be used. Therefore every medical device which needs to be sterilised has to be packed. The choice of packaging material depends on several important criteria:

The medical device which has to be packed.
The sterilant has to pass through (porosity).
The material should not release any harmful substances nor go through considerable change (chemically or physically) during sterilisation.
The material has to pack easily, so it has to be soft, yet strong during packaging, sterilisation, transport, and storage.
It must show damages and not create false safety (pinholes).
The packaging material must prevent recontamination.
Aseptic opening must be possible.
The material is possibly being used as a sterile field, meaning it has to be repellent towards low-tension liquids. We counted in a university hospital 13 different kinds of low-tension liquids used in the OR.
The material must be lintfree. Lint is a potential hazard for the patient.

The loss of sterile package integrity is usually regarded as an event related, rather than time related.
Shelf life is a complex matter and depends on a lot of different factors, which have to be taken into consideration, like e;g.:

How stable is the medical device that has been packed.
How stable are the raw materials of which the packaging material is manufactured.
The change of penetration of microorganisms during transport / storage.
How and by whom has it been packed.
The method of sterilisation.
The way of transport.
Storage conditions.
How easy is it to open the packaging aseptically and how has it been opened in the theatre?

The advice is to use always two layers of sterilisation wrap and to wrap the medical device subsequently. There are several reasons for this advice:

Two sheets used in a single action are in practice only one sheet. To create a tortuous path to prevent migration of organisms from reaching the sterile contents different folds are necessary, which can be created by subsequently packing two sheets.
To use different qualities, dimensions and interleaved colours to be able to differentiate between sterile and non-sterile, and to facilitate detection of damage to the packaging in the theatre. With interleaved colours damages like holes or tears are more easily detected.
Using interleaved coloured wrap you always know that you have subsequently wrapped. Due to the colours you do not forget a layer.
If the outside of the inner pack is expected to be sterile, double wrapping is necessary and makes it easier to distinguish sterile and non-sterile.
To facilitate aseptic opening.

The industry is working to all kinds of quality systems and are trying very hard to supply you with the best quality products.
So you can supply the best quality to your customers like the theatre and the patient.
Why is quality so important?

Better control over the process
Increasing and improve productivity and quality
Lower cost
Satisfied customers/patients
Manufactures can provide you with the best quality of packaging materials but what if it is wrongly packed or opened?

Sterile barrier systems materials are a vital part of the medical device for the hospital and industry. Budgeting on packaging materials is the wrong thing to do. After all, we are talking about the safety of the patient.

Packaging - legal and normative requirements

CEN TC 102 WG 4 was established on May 3rd 1988, to deal with European Standards concerning single use and reusable packaging. The aim was to harmonise all existing European Sterilization Packaging Standards, like DIN (German), AFNOR (French), BSI (British), Steriliseren Steriliteit (Dutch) and others.
A working group is restricted to individual members appointed by the parent body or by CEN, to serve as an expert.
Members to WG 4 are i.e.:

Hospitals
SBA - Sterile Barrier Association (formerly ESPA - European Sterilisation Packaging Association)
EDANA - European Disposable and Nonwovens Association.
EUCOMED - European Confederation of Medical Devices Associations.
Departments of Health and others.

Document EN 868-1 has been ratified and was published in the official European Journal in February 1997.
This document is in line with the Medical Device Directive and all packaging materials will have to fulfil Part EN 868-1 " Packaging Materials and Systems for Medical Devices Which Are to Be Sterilised - Part 1 General Requirements and test methods".
Documents EN 868 - 2 and subsequent parts are dealing with the requirements and test methods and can be used to show compliance with these particular requirements. (A tool to proof compliance to part 1). Products in compliance with these requirements are in compliance with part 1.
Non-compliance to these parts of the standard, however, does not mean or infer non-compliance to part 1.
Parts 2 to 8 have been ratified and were published in June 1999.
Standards are tools to prove the conformity with the Medical Device Directive.
European standards published by CEN have to be transcribed without any modification into national standards, and as a result all pre-existing national standards dealing with the same contents and contracting the European standard will be cancelled.
On a global scale, we have the International Standardization Organization (ISO). Within the ISO there is the Technical Committee 198 Working Group 7; this WG has published document ISO/FDIS 11607 "Packaging for Terminally Sterilized Medical Devices ".
The big difference between these and the EN 868 documents is that the ISO document is dealing with forming and sealing and does not conform to the Medical Device Directive. ISO/TC 198 has agreed in Kyoto that a joint combined revision of
ISO 11607, EN 868-1 will be developed under the Vienna agreement, with an ISO lead, to create one global packaging standard.
It is very important that the future new packaging standard has to show compliance with the essential requirements or other provisions of the European Directives.

The new harmonised standard will consist of two parts:

Packaging for Terminally Sterilized Medical Devices - Part 1: Requirements for Materials, Sterile Barrier Systems and Packaging.
Packaging for Terminally Sterilized Medical Devices - Part 2: Validation and Requirements for Forming, Sealing and Assembly Processes.

This International Standard is applicable to industry, health care facilities, and wherever medical devices are packaged and sterilised. CSSD in hospitals will be considered as "industry" as well - as far as I am concerned this the right decision. For where is the difference between hospitals and manufacturers? Let us not forget that we are talking about the safety of the patient.

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