SMTL are on the move - to a new laboratory in the Princess of Wales Hospital.

Many of you will be aware that Bridgend General Hospital has been closing down slowly over the last few years, with all departments gradually relocating to the Princess of Wales Hospital. In March, the last department moved, leaving SMTL on its own at the General.

Fortunately, funding became available for a replacement laboratory on the Princess of Wales site. Building work started in January of this year, and construction is now nearly complete.

The new laboratory is smaller than our current premises, but has the advantage of being built to our specification. It includes a Controlled Environment Laboratory, Biosurgery Unit, Physical Testing Laboratory, Chemistry Laboratory, Microbiology Laboratory and Cell Culture Laboratory.

SMTL expect to start the move on 21st July. Once all the laboratory equipment has been moved, it has to be re-commissioned and this will be followed by a re-inspection from UKAS (the United Kingdom Accreditation Authority) to enable our NAMAS accreditation to be transferred from the current laboratory to the new premises. We anticipate that the new laboratory will be up and running by mid-September 1998.

SMTL will be hosting a number of open days to enable users of SMTL's services to see the new laboratory. If you wish to be included on the list of guests, please ring Tony or Rhian at SMTL and ask to be placed on the guest list. Contact information is on the last page of this issue. S. Thomas, P Phillips

Storage of medical disposables and dressings.

Many medical and surgical disposables are subject to deterioration. For example, latex gloves can easily be damaged if stored close to a source of high voltage electricity, polypropylene syringes may become brittle after storage at high temperatures, and paper packaging can become soft and easily damaged when damp.

Correct storage conditions and adherence to expiry dates is therefore of vital importance to ensure that staff and patients are not subjected to unnecessary risks.

Many medical and surgical disposables are subject to deterioration. For example, latex gloves can easily be damaged if stored close to a source of high voltage electricity, polypropylene syringes may become brittle after storage at high temperatures, and paper packaging can become soft and easily damaged when damp.

Correct storage conditions and adherence to expiry dates is therefore of vital importance to ensure that staff and patients are not subjected to unnecessary risks.

Expiry Dates

With the implementation of the Medical Devices Directive (MDD) (93/42/EEC) in Europe in June 1998, the MRS has ended, and the system of CE marking takes its place.

The MDD deals with expiry dating in Annex I, "Essential Requirements", paragraph 13.3 (e) and (i) as follows:

The label must bear the following particulars:

(e) - where appropriate, an indication of the date by which the device should be used, in safety, expressed as the year and month; There is no definition explaining what is meant by appropriate.

(i) - any special storage and/or handling conditions;

Welsh Health Circular WHC(88)26 ("Procurement Product Liability", Department of Health and Social Security, "WHC(88)26 / WHC(FP)(88)11.") states that Health Authorities should be able to show that instructions or warnings in relation to use, maintenance, storage, expiry dates etc, have been observed and/or passed on to the user. As long as this advice is adhered to, the manufacturer is "strictly liable" for the product (under the "Consumer Protection Act 1987").

Conversely, if the manufacturers advice is ignored, then there is the possibility that the Trust, or the person responsible for the handling of the product, will become strictly liable for the defective goods.

Handling and Storage Conditions

Guidelines referring to storage conditions from the old "White Guide" ("Guide to good manufacturing practice for sterile medical devices and surgical products", 1981, Department of Health an Social Security) are still useful:

• Conditions should be such as to minimise deterioration or contamination and prevent damage. Containers should afford adequate protection.
• If special environmental storage conditions are required at any stage, such conditions should be controlled and monitored.
• Storage conditions should be orderly to facilitate rotation of stock, batch differentiation (to enable product withdrawal a relatively simple and painless procedure) and ease of cleaning.

In general, precautions should be taken to protect the items from the effects of:

• moisture (eg: do not store under damp conditions)
• heat (eg: do not store near to, or on top of, radiators)
• light (eg: do not store in direct sunlight).

Where no specific storage conditions or limitations are specified, it is generally understood that the storage conditions include protection from moisture, freezing and excessive heat.

Should prolonged temperature rises of 5 or 6⁰C be experienced, then shelf life could be significantly reduced. Extreme storage conditions such as exposure to direct sunlight and/or storage on top of (or near to) radiators could destroy the product, and should be avoided at all costs.

Occasionally, products may have been stored under inappropriate conditions. Under these circumstances, advice should be sought from the issuing department or the manufacturer.

Specific Guidelines for Latex products

Latex products and products containing latex (for example, IV sets) require special care as latex is especially prone to deterioration if stored under incorrect conditions.

In particular, latex products should be protected from

• high temperatures
• ozone
• high voltage electrical sources, including storage close to fluorescent lights
• strong light sources, including direct sunlight

In the Spring and Summer of 1995, the spontaneous combustion of powder-free latex gloves in 4 different states in the USA lead the FDA to produce advice on storage of chlorinated latex gloves.

Most of the guidelines are the usual ones designed to prevent product deterioration (rotate stock, avoid storing in conditions of extreme heat etc), but some are designed to reduce the risk of spontaneous combustion. The fires were believed to have started due to high warehouse temperatures apparently accelerating an exothermic chemical reaction on the chlorinated gloves to the point where the latex ignited. Thus the FDA advise not storing large quantities of powder free latex gloves in conditions of extreme heat. The FDA consider one pallet or more to be a "large quantity".

They also advise removing the shrink wrap from pallets of stacked cartons, breaking stacked cartons on each pallet apart, and re-stacking or reconfiguring cartons to facilitate cooling. The gloves should be checked periodically for deterioration, including brittleness, tackiness, or an acrid chemical odour or stench. The complete FDA report is available on the Internet at http://www.fda.gov/cdrh/glovepha.html

Dressings

The previous British Pharmacopoeia (1993) recommends that Surgical dressings should be kept in a dry, well-ventilated place at temperatures not exceeding 25⁰C. Adverse conditions, such as excessively humid, cold or hot locations, strong light sources and sources if electrical energy, can cause plastics, rubber and cellulose materials to become brittle, perished, stained or malodorous; such effects may be aggravated by lengthy exposure.

Regarding sterile surgical dressings, the 1993 BP states: Sterile surgical dressings should be stored in the shelf container; the unit container should be removed from the shelf container immediately before use. If a pack becomes damaged, wet, or otherwise soiled, it is regarded as being unsafe for use.

These recommendations are particularly important in relation to adhesive products, especially those covered with a rubber/zinc oxide adhesive mass.

Definitions

The British and European Pharmacopoeias give useful definitions of temperatures ranges as follows:

• Storage in a deep freeze - below -15⁰C
• In a refrigerator - 2⁰C - 8⁰C
• Cold/Cool - 8⁰C - 15⁰
• Room Temperature - 15⁰C - 25⁰C

The full report on which this article is based is available from SMTL and on the Internet at http://www.smtl.co.uk/MDRC/Storage/ P Phillips

What is NAMAS accreditation.

SMTL was successful in gaining NAMAS accreditation for testing medical disposables and dressings in November 1995.

SMTL spent 4 years introducing and implementing a comprehensive quality system which was inspected by independent experts as part of the accreditation process. SMTL were the first UK laboratory to have been accredited in the category of "Medical Disposables and Dressings".

So what does this accreditation status mean ?

• Testing carried out by SMTL on medical disposables (such as gloves, bandages, dressings, catheters) is assured to have been performed to the highest standards.
• Clients of SMTL are assured that agreed methods and procedures have been followed.
• Measurements made by SMTL are traceable to national and international standards.
• Test reports and certificates produced by SMTL will be recognised and accepted within the UK and throughout the world, including France, Denmark, Ireland, New Zealand, Hong Kong, Sweden and the Netherlands.

When UKAS inspects a laboratory for accreditation purposes, it assesses a number of criteria, including:

• Organisation
• Quality Systems
• Quality audits and reviews
• Staff
• Equipment
• Measurement traceability
• Methods and procedures
• Environment
• Sample handling
• Records
• Complaints
• Sub-contracting and purchasing

SMTL was successful in gaining NAMAS accreditation for testing medical disposables and dressings in November 1995.

SMTL spent 4 years introducing and implementing a comprehensive quality system which was inspected by independent experts as part of the accreditation process. SMTL were the first UK laboratory to have been accredited in the category of "Medical Disposables and Dressings".

So what does this accreditation status mean ?

• Testing carried out by SMTL on medical disposables (such as gloves, bandages, dressings, catheters) is assured to have been performed to the highest standards.
• Clients of SMTL are assured that agreed methods and procedures have been followed.
• Measurements made by SMTL are traceable to national and international standards.
• Test reports and certificates produced by SMTL will be recognised and accepted within the UK and throughout the world, including France, Denmark, Ireland, New Zealand, Hong Kong, Sweden and the Netherlands.

When UKAS inspects a laboratory for accreditation purposes, it assesses a number of criteria, including:

• Organisation
• Quality Systems
• Quality audits and reviews
• Staff
• Equipment
• Measurement traceability
• Methods and procedures
• Environment
• Sample handling
• Records
• Complaints
• Sub-contracting and purchasing

How is this different from ISO 9000 ?

Laboratories meeting NAMAS requirements for calibration and testing activities comply with the relevant requirements of BS 5750 / ISO 9000 series of standards, including the model described in ISO 9002 when they are acting as suppliers producing calibration and test results.

Laboratories that are associated with manufacturing operations and offer a calibration or testing service need to be NAMAS accredited to provide an acceptable level of confidence, even if the manufacturing operation holds BS 5750 / ISO 9000 approval.

SMTL believe that the effort and expense associated with maintaining NAMAS accreditation are justified in terms of the level of service provided to the NHS in Wales, Welsh Health Supplies, and other customers in the medical device industry. If you have any questions about NAMAS accreditation of SMTL, please contact Dr S. Thomas or Mr P. Phillips at SMTL. P Phillips

Antibiotics from maggots ?

The use of sterile fly larvae, maggots, in the management of leg ulcers, pressure sores and other chronic wounds is becoming increasingly widespread. Clinical experience with these creatures suggests that they not only remove slough and necrotic tissue but also combat wound odour and infection, including that caused by strains of bacteria that are resistant to antibiotics such as Methicillin Resistant Staphylococcus aureus (MRSA). This wound cleansing action is a critical step in the healing process.

Larvae feed by secreting powerful proteolytic enzymes that dissolve dead tissue and form it into a 'soup' which they then ingest as a source of nutrient. During this process they also ingest bacteria, most of which are killed as they pass through the gut.

The use of sterile fly larvae, maggots, in the management of leg ulcers, pressure sores and other chronic wounds is becoming increasingly widespread. Clinical experience with these creatures suggests that they not only remove slough and necrotic tissue but also combat wound odour and infection, including that caused by strains of bacteria that are resistant to antibiotics such as Methicillin Resistant Staphylococcus aureus (MRSA). This wound cleansing action is a critical step in the healing process.

Larvae feed by secreting powerful proteolytic enzymes that dissolve dead tissue and form it into a 'soup' which they then ingest as a source of nutrient. During this process they also ingest bacteria, most of which are killed as they pass through the gut.

Laboratory Study

It is also believed that larval secretions have an inherent antibacterial action which enables them to kill bacteria within the wound itself. The activity of secretions of sterile larvae of Lucilia sericata, the common greenbottle has recently been investigated in a pilot study conducted in the Biosurgical Research Unit using a series of test methods developed for this purpose. Although a number of different techniques were used, the best method was found to be one which measured and compared the change in optical density of a bacterial suspension in the presence and absence of larval secretions. In this context, optical density is a function of the number of bacteria present.

Using this method, larval secretions were collected and tested against a number of different microorganisms. The results indicate that the Gram positive bacteria , Staphylococcus aureus, and Streptococci A and B were particularly susceptible resulting in bacterial cell death and that this effect was dose related. The growth rate of an antibiotic-resistant strain of S. aureus was also inhibited compared with control values.

Gram negative bacteria were less susceptible to the activity of the secretions although some inhibitory effects were noted against Pseudomonas aeruginosa. The reported ability of larvae to eradicate clinical infections caused by Gram negative organisms suggests that they must be destroyed in the larval gut following ingestion as previously described rather than by the activity of the secretions themselves. The results of this preliminary work are consistent with reported clinical observations that larvae are able to combat wound infections caused by a number of pathogenic organisms including those that are antibiotic resistant. The results may also help to explain the impressive results reported recently following the use of larvae in the management of diabetic ulcers ("Use of larvae in the treatment of the diabetic foot", Rayman A. et al, The Diabetic Foot, Vol 1, No 1, 1998, p7-13). S. Thomas, A. Andrews

SMTL on the Web - http://www.smtl.co.uk/

Most of you will know `by now that SMTL have a Web site containing a wealth of information on dressings, disposables and woundcare. This section lists a number of the most recent and interesting articles you can find on the site.

Most of you will know `by now that SMTL have a Web site containing a wealth of information on dressings, disposables and woundcare. This section lists a number of the most recent and interesting articles you can find on the site.

World Wide Wounds

World Wide Wounds, the electronic journal of wound management practice, can be found at http://www.smtl.co.uk/World-Wide-Wounds/

Recent articles include:

• Frequently Asked Questions on Alginate Dressings
• Frequently Asked Questions on Hydrocolloid Dressings
• Odour Absorbing Dressings: A comparative laboratory study - a new method of assessing the performance of odour absorbing dressings is described.
• Case study: Larval therapy for an infected insect bite.
• The management of extravasation injury in neonates.

The Medical Devices Resource Centre

In the MDRC (http://www.smtl.co.uk/MDRC/), there are a number of new articles as follows:

• I.V. Administration Sets with in-line filters.
• News

  The News section carries details of Seton's takeover of EMS Medical's urology business, Regulatory news regarding the interpretation of the Medical Device Directive, and information about the 3M hip implant problem.

• The Hazards and Safety Action Bulletins section contains information about the withdrawal of the DoH product approval schemes for chemical indicators used in the Bowie and Dick test and recalls of a number of defibrillation electrodes.