Section 4-1: Review of wound management materials - (Untitled Section)

This sections contains a brief review of the dressings contained within the Drug Tariff, together with those pharmaceutical items in Section 13.10 and 13.11 of the Welsh Prescribing Catalogue that are used in wound management. This section is intended to provide users with background information on the products that are available in an easily understandable form and explain, where possible, how the physical properties of these materials influence their clinical applications as described in Section 4.

Primary wound dressings

Hydrocolloid dressings - Key features

Three hydrocolloid dressings are listed in the Drug Tariff, and these vary significantly in their composition and physical characteristics. The products differ in price, but in the absence of hard published data on their relative clinical effectiveness, it is not possible to make any recommendation on preferred usage.

• Hydrocolloid dressings consist of a self-adhesive gel-forming mass which may contain sodium carboxymethylcellulose, gelatin and pectin, applied to a carrier such as a thin polyurethane film or foam sheet.
• Used for light to moderately exuding wounds including pressure sores[Image-15K],minor burns[Image-16K] and traumatic injuries. Also used extensively in the management ofleg ulcers[Image-16K] where they appear to have advantages in the treatment of wounds that fail to respond to compression therapy alone.
• In their intact state, hydrocolloids are initially virtually impermeable to water vapour and for this reason they are often used to facilitate rehydration and autolytic debridement of dry sloughy or necrotic wounds[Image-16K].
• Because hydrocolloid dressings do not cause pain on removal, they are particularly useful in paediatric wound care for the management of both acute and chronic wounds.

Semipermeable adhesive film dressing - Key features

There are currently four adhesive film dressings available on the Tariff. They are all made from a thin sheet of polyurethane coated with a layer of acrylic adhesive.

• The dressings are permeable to moisture vapour and gases but impermeable to liquids.
• Film dressings have a wide range of applications. Their use has been reported in burns, donor sites[Image-16K], surgical wounds and superficial pressure sores[Image-15K]. They are also used as secondary dressings in combination with alginates and hydrogels and are applied prophylactically to prevent damage caused by shearing forces to the skin of patients confined to bed.
• Although the physical properties of the films from which the dressings are constructed are broadly comparable major differences exist in the application systems that have been developed.
• Users often express a strong preference for a particular brand of film dressing because they have become familiar with its method of use. It is argued that a change to an alternative product with a different application system could lead to wastage and therefore increase rather than reduce costs.
• Despite the `brand loyalty' shown to particular makes of dressing, significant savings are possible if prescribing practices can be changed.

Perforated film absorbent dressings - Key features

Three perforated film dressings are included in the Drug Tariff; These dressings are designed to combine a degree of absorbence with low-adherence for the management of lightly exuding superficial wounds.

• They consist of an absorbent fibrous fleece covered with a plastic film containing a series of small holes arranged in a uniform pattern.
• The plastic film is intended to prevent the dressing adhering to the surface of the wound and the holes are present to allow the passage of exudate through to the absorbent layer.
• Perforated film absorbent dressings are widely used in the treatment of superficial wounds and are frequently applied in combination with hydrogels or alginates.
• The ability of these dressings to absorb exudate is limited, and for heavily exuding wounds they are sometimes covered with a second absorbent pad. In these situations the absorbency of the dressing is less important than its low-adherent properties.

Alginate dressings - Key features

Alginate dressings are produced from the calcium and sodium salts of alginic acid, a polymer obtained from seaweed that is composed of mannuronic and guluronic acid residues.

• Calcium alginate is insoluble in water but in the presence of sodium ions from wound exudate, a partial ion exchange reaction takes place resulting in the production of sodium alginate which forms a hydrophilic gel on the wound surface that is believed to facilitate healing.
• The physical and chemical properties of the dressings depend upon the content of calcium and sodium ions and the relative concentration and arrangement of the mannuronic and guluronic monomers. Dressings rich in mannuronic acid, tend to react readily with sodium ions, forming soft amorphous gels. Dressings rich in guluronic acid gel less readily and form firmer less mobile gels.
• Five alginate dressings are available on the Drug Tariff. Most consist of calcium alginate formed into textile fibres.
  • Sorbsan consists primarily of fibres of calcium alginate rich in mannuronic acid.
  • Kaltostat is produced from fibres of calcium/sodium (80:20) alginate rich in guluronic acid.
  • Tegagel is chemically similar to Sorbsan but more closely resembles Kaltostat in appearance.
  • Kaltogel, a new addition to the Tariff, is also rich in mannuronic acid but also contains 20% sodium alginate to facilitate rapid gelling.
  • Comfeel Alginate Dressing, rich in guluronic acid, is made by a freeze drying process and is therefore a fibre-free mass of calcium alginate which is supported on a nylon mesh net.
• Alginate dressings are used primarily for the treatment of exuding wounds such as leg ulcers, acute surgical wounds sinuses[Image-15K] and other cavity wounds such as pressure sores[Image-15K].
• Alginates also have haemostatic properties, and one product, Kaltostat, has a product licence for this application.
• The chemical and physical properties of the alginate dressings are very different and this has implications for the selection and method of use of the products concerned. Sorbsan and Kaltogel are soluble in 0.9% sodium chloride solution and is therefore easily removed from a cavity wound or sinus[Image-15K] by irrigation. Tegagel and Kaltostat are less soluble and therefore may be removed from the wound intact as may the Comfeel product.
• Although there is some anecdotal evidence to indicate that at least one alginate, Sorbsan, may be of value in the management of sloughy, necrotic orinfected wounds[Image-16K] but this has not been confirmed in a clinical trial.

Low-adherent wound contact layers - Key features

Low-adherent wound contact layers are used as interface layers to prevent a secondary absorbent dressing from adhering to the surface of a wound and causing trauma on removal. They are available both plain and impregnated with white soft paraffin which may also contain an antibacterial agent.

Unmedicated low-adherent wound contact layers

• Knitted Viscose Primary Dressing BP, more familiarly known as NA Dressing or Tricotex, is a simple knitted fabric that is claimed to have limited adherence properties. This dressing is commonly used as the initial layer of the Four Layer Bandage system.
• For many applications, NA Dressing and Tricotex have largely replaced paraffin gauze dressings (tulles), which, despite their greasy nature and description of `low-adherent dressings', often become firmly attached to the surface of a wound causing pain or discomfort upon removal.

Medicated low-adherent wound contact layers

Paraffin gauze dressings can be medicated with antibiotics such as sodium fusidate and framycetin but these may cause sensitivity reactions and the development of resistant strains of micro-organisms.

• Dressings such as Bactigras and Serotulle contain an antiseptic, chlorhexidine, instead of an antibiotic and are therefore generally considered to be free of these disadvantages.
• Laboratory tests suggest that the chlorhexidine is not readily released from the hydrophobic paraffin base and therefore the antibacterial activity of these dressings is likely to be limited.
• Inadine contains povidone iodine in polyethylene glycol which is hydrophilic and therefore better able to liberate the antimicrobial agent into wound exudate in order to exert a bactericidal effect.

Hydrogel dressings - Key features

Hydrogels consists of insoluble polymers with hydrophilic sites which interact with aqueous solutions, absorbing and retaining significant volumes of water.

• Intrasite gel, the only hydrogel is currently available in the Drug Tariff, contains approximately 1-2% carboxy-methylcellulose, 80% water, and 20% propylene glycol as a humectant and preservative.
• The gel has the ability to absorb or donate liquid according to the state of hydration of the tissue to which it is applied.
• Intrasite is also sometimes used as a carrier for metronidazole in the treatment of fungating and other malodorous wounds.
• The primary indication for the use of the gel is the cleansing of sloughy and necrotic wounds[Image-16K] which it does by rehydrating dead tissue and encouraging autolytic debridement.
• Intrasite gel can be used for the management of problem wounds such assinuses[Image-15K] and infected surgical wounds that may be difficult to dress with alternative products.
• The gel has also been used with advantage in the treatment of extravasation injuries in neonates.
• A generous layer of gel is applied to the surface of a wound and covered with a perforated plastic film dressing such as Melolin or Release or a semipermeable adhesive film depending upon the location and condition of the lesion.
• On very dry wounds it is usual to change the dressing at least once per day.

Polysaccharide bead dressings - Key features

Dressings made from polysaccharide beads were amongst the first `modern' products to be used in wound management. Two different types of beads are available which are used in a number of different formulations.

• Debrisan consists of absorbent dextranomer microspheres about 0.2 mm in diameter. When introduced into a wound the beads absorb exudate and cellular debris and so assist with wound debridement
• Because of practical problems associated with the use of the free flowing beads, they are also produced in the form of a paste in which they are mixed with polyethylene glycol.
• Debrisan Absorbent Pads are textile bags containing Debrisan Paste that can be easily applied to, and removed from, an appropriate wound.
• Iodosorb consists of microspheres of chemically modified starch which contain 0.9% elemental iodine which is released when the beads absorb water and swell.
• Like Debrisan, Iodosorb is used for the treatment of moist sloughy wounds particularly when infection is present.
• Also like Debrisan, Iodosorb is available in the form of a paste or ointment which is used in situations were application of the free flowing beads would be impractical.
• Iodoflex, used in the management of relatively large shallow wounds, consists of a layer of Iodosorb ointment sandwiched between two pieces of gauze, one of which is removed before the dressing is applied to the wound surface.

Polyurethane foam dressing - Key features

There are five polyurethane foam dressing included in the Drug Tariff which have very different performance characteristics and indication.

• Lyofoam consists of an open-cell polyurethane foam sheet, one surface of which has been heat treated to collapse the cells of the foam and allow it to take up blood or wound exudate by capillarity. It is used in the management of a variety of different wound types including leg ulcers, traumatic wounds,minor burns[Image-16K] , and donor sites[Image-16K]
• Unlike most absorbent dressings, Lyofoam transmits absorbed fluid laterally across the face of the dressing rather than from front to back. For this reason, a size of Lyofoam should always be selected which overlaps the edges of the wound by about 2-3 cm.
• Allevyn is three component dressing consisting of a hydrophilic polyurethane foam layer about 3 mm thick sandwiched between a low-adherent net facing layer and a polyurethane film backing. The dressing is highly absorbent and is useful for the management of moderate-heavily exuding wounds such as legulcers[Image-16K] and fungating tumours.
• Allevyn adhesive consists of a piece of Allevyn foam which is bonded to a piece of polyurethane foam to form an island dressing the surface of which is coated with adhesive.
• Spyrosorb is thin sheet of polyurethane foam coated with adhesive. The dressing which is very conformable, has limited absorbent capacity but is highly permeable to moisture vapour. It is used for dressing relatively shallow, lightly exuding wounds or wounds in the final stages of healing.
• Tielle is a sophisticated island dressing consisting of a piece of polyurethane film/foam, located in the centre of an adhesive moisture vapour permeable, polyurethane membrane. The dressing is highly permeable to moisture vapour which makes it suitable for application to moderately exuding wounds despite its limited absorbent capacity.

Miscellaneous dressings

Miscellaneous wound management products that are included in the Drug Tariff are shown below.

Dressing packs

Dressing packs, sometimes also called procedure packs, provide the nurse practitioner with a selection of sterile wound care items conveniently packaged together. Four different packs are included in the Drug Tariff.

• Pack A, (Drug Tariff Specification 10), contains woven cotton swabs and a piece of gauze and cotton tissue (Gamgee).
• Pack B (Drug Tariff Specification 35) contains nonwoven swabs and a proprietary dressing pad. Both packs also contain absorbent cotton balls, a paper towel and an inner wrap that opens out to form a sterile field. These packs are generally used when changing a dressing or carrying out some similar procedure.
• Multiple dressing packs 1 and 2 contain absorbent cotton rolls, absorbent gauze and white open wove bandages. These items are intended to be used together to form a dressing. The precise indications for the use of these packs is uncertain but they are relatively expensive and as there can be little place for a dressing made from these three components in modern wound management, their use should be discontinued in favour of more cost effective alternatives.

Note

The expenditure upon dressing packs quoted in the table above does not reflect the total sum spent in Wales on these items. At least one very large Authority purchases their packs from the hospital CSSD and this expenditure is not reflected in Table 12

Surgical absorbents

Surgical absorbents are products which, although not designed to be left in intimate contact with damaged tissue, may be used for cleansing purposes or as secondary absorbent layers over a primary dressing in the management of heavily exuding wounds.

Cotton/nonwoven swabs - Key features

• Surgical swabs are traditionally produced from Gauze, a simple woven fabric made from absorbent cotton.
• Developments in textile technology have led to the production of nonwoven fabrics manufactured principally from viscose which have a number of advantages over woven cotton.
• Nonwovens are generally more absorbent and are less likely to shed fibrous material into the wound which may delay healing or predispose the wound to infection.They are also significantly cheaper.
• Filmated swab contains a thin layer of absorbent cotton (cotton wool) which is included to improve the fluid handling properties, although the presence of the loose cotton fibres must increase the risk of particulate loss from the finished product.
• Filmated swabs may be manufactured from either woven or nonwoven fabric but laboratory tests have shown that despite the presence of the fibrous cotton interliner, the filmated swabs available upon prescription are inferior in performance terms to the ordinary nonwoven product despite being significantly more expensive

Figures in ( ) indicate expenditure for period July 1993-June 1994.

Gauze and cotton tissue - Key features

More familiarly known by its trade name of `Gamgee Tissue' it consists of a layer of absorbent cotton enclosed in a sleeve of cotton gauze.

• Gamgee tissue is used to absorb exudate from heavily exuding wounds and should be applied over a primary wound dressing to avoid contaminating the wound with cellulose fibres.

Absorbent cotton rolls - Key features

• Absorbent cotton (cotton wool) should not be used as a dressing material because of the problems of fibre loss.
• The material available on the Tariff is not sterile and this should also preclude its use as a primary wound dressing.
• Absorbent cotton is sometimes used as a padding material under bandages to prevent pressure damage to tissue over bony prominences, and for swabbing skin prior to injection.
• Over 13 metric tons of absorbent cotton are prescribed annually in Wales.

Absorbent lint - Key features

• Like absorbent cotton, lint sheds excessive amounts of fibrous material and therefore has no place in wound management.
• Discussions with community nursing staff indicate that they never use it and therefore it must be assumed that it is provided direct to patients for some undefined purpose.

Absorbent gauze rolls - Key features

• Absorbent gauze rolls, including ribbon gauze, are available in both the sterile and non sterile form.
• Sterile ribbon gauze and the sterile version of the larger rolls product is sometimes used for packing wounds but there is no information to suggest what the non sterile material is used for.

Cellulose Wadding - Key features

• Cellulose wadding consists of a layer of cellulose wadding in a tube of cotton gauze.
• The product is not sterile and is used principally as an absorbent for non-surgical applications (e.g. incontinence). It should therefore not be regarded as a dressing.

The items marked * in the table above are available in a range of sizes. The values quoted here for the number of items prescribed represent the sum of all sizes in each case.

Extensible/Bandages

The bandages in the Drug Tariff may be classified into groups according to their function and performance. Considerable financial savings may be achieved by ensuring that these are used appropriately.

Retention bandages -Key features

As their name suggests, these bandages are used to retain dressings in place. They should not be used to apply pressure as they are unsuitable for this purpose.

• The first `retention bandage' was White Open Wove (WOW) a rigid fabric with extremely limited conformability that is available in a range of widths.
• Because of the poor performance characteristics of WOW two softer more conformable bandages were introduced. These are Kling and Crinx the Cotton Conforming Bandages of the British Pharmacopoiea.
• Recently, new lightweight bandages have been developed that have advantages over the simple cotton products. Some of these are included in the Tariff, and although they vary in performance and price, all of them are cheaper than the products they are designed to replace.

Support Bandages - Key features

Support may be defined as the retention and control of tissue without the application of compression. It is usually provided to prevent the development of a deformity or change in shape of a mass of tissue due to swelling or sagging.

• The support bandages available on the Drug Tariff are Crepe Bandage BP, woven from cotton and wool, and Cotton Crepe Bandage BP - more familiarly known as Elastocrepe which is made entirely of cotton.
• Both types of bandage have been used to provide support in the treatment of sprains and strains and to apply compression in the management of leg ulcers caused by venous insufficiency.
• Numerous published studies have demonstrated, however, that the elastic properties of these bandages are such that they are unable to provide and maintain the levels of pressure that are required for this indication and therefore they should not be used for this purpose.
• Competent compression bandages containing elastomeric yarns are much better suited for this application, and these are described in the following section.
• It is likely that a significant proportion of all crepe bandages supplied are used inappropriately for dressing retention. This is not cost effective, for these bandages are much more expensive than the bandages described in Table 16.

Compression Bandages - Key features

Compression implies the application of clinically effective levels of external pressure, applied to modify or assist a physiological process - generally blood flow. The bandages in the Drug Tariff that are suitable for the application of high levels of compression are shown in Table 18.

• The inappropriate use of compression bandages can have very serious consequences, resulting in extreme cases in necrosis and amputation[Image-0K]
• It is vitally important that no form of high compression bandaging system is applied to a patient unless the possibility of arterial disease has first been excluded by some appropriate method.
• Where crepe bandages are being used to provide compression, a change to a more effective product such as Setopress or Tensopress should be considered.
• When crepe bandages are being used to apply compression, a change to a more clinically effective product will result in an increase in expenditure but an improvement in patient care.

Adhesive bandages Key features

Adhesive bandages are generally applied to provide support rather than compression. The adhesive coating helps to ensure that the bandages do not slip or become displaced.

• Adhesive bandages are comonly used for strapping purposes and to provide support or compression in the treatment of sprains and strains.
• Diachylon adhesive bandage, more commonly known as Lestreflex, is often used in place of bandages coated with a zinc oxide adhesive where skin sensitivity reactions are present or suspected.

Surgical Tapes

• Surgical tapes are used to retain dressings and other medical appliances in position. A number of types are available with various backing materials and adhesive systems.
• Traditional woven products coated with a zinc oxide-rubber adhesive have been largely replaced by paper tapes bearing synthetic acrylic adhesives for general purpose use such as dressing retention.
• Plastic tapes such as Sleek and Blenderm are used where more long term adhesion is required, particularly in the presence of moisture as in the fixation of drains.
• A finely woven tape coated with a synthetic adhesive, Leucosilk, is available where tensile strength and low sensitisation potential is important.
• The majority of expenditure on surgical tapes is on the paper products. Micropore is brand leader within this group but substantial savings could be achieved by the use of alternative products if these are judged to be clinically acceptable.

Paste Bandages

Paste bandages consist of an open woven cotton fabric impregnated with a medicated paste or cream, most of which contain zinc oxide.

• Paste bandages are used for the treatment of eczema[Image-15K], dermatitis[Image-15K] and similar conditions.
• They are also often applied in conjunction with compression bandages in the management of venous ulcers
• The principal problem associated with the use of paste bandages is their tendency to induce skin reactions. This is largely due to the presence of parabens preservatives.
• A recent addition to the Tariff, Steripaste, is preservative free and is therefore claimed to be less likely to induce skin reactions.

Tubular Bandages and Stockinettes

The Drug Tariff contains several different types of tubular bandages and stockinettes (Table 22)

Elasticated Tubular Bandage

Available in a range of sizes from a number of manufacturers, Elasticated Tubular Bandage is applied in multiple layers to provide a degree of pressure and support and following soft tissue injuries. Despite the fact that it is commonly used in the treatment of venous legulcers[Image-16K], Elasticated Tubular Bandage it is not really suitable for this purpose as the pressure it produces falls far short of that which is required clinically. Although one brand has approximately 99% of the market, significant financial savings may be achieved by the use of alternative brands where direct substitutions are possible.. Some caution is required in this context, however, as the pressure profiles of the six products may vary.

Lightweight Elasticated Tubular Bandages

Two types of lightweight elasticated tubular bandage are included in the Tariff.

• Tubifast is a lightweight elasticated stockinette that is particularly useful for holding dressings in place on digits and limbs.
• Netelast has an open net-like structure and can be cut and fashioned into garments to retain dressings on awkward anatomical sites such as the head or groins region.

Plain Stockinette

Plain Stockinette is primarily used under orthopaedic casts and as a protective covering following the application of greasy ointments for the treatment of dermatological conditions.

Foam Padded Elasticated Tubular Bandage

• Foam Padded Elasticated Tubular Bandage (Tubipad) consists of a length of Elasticated Tubular Bandage into which is sewn a piece of foam.
• The bandage is used to provide padding and protection against physical damage particularly for elbows, knees etc.

Pharmaceutical preparations

A summary of expenditure on the pharmaceutical preparations used in wound management extracted from Sections 13.10 and 13.11 of the Welsh Prescribing Catalogue is shown in Table 23. Other products such as the polysaccharide bead dressings Debrisan and Iodosorb, which are also included in Section 13.11 of the Catalogue, do not appear in this table as these have been identified separately as `polysaccharide bead dressings' in Table 9

Wound cleansing agents - Key features

Wound cleansing agents are solutions that are used to cleanse wounds prior to the application of a dressing. As such they should not be confused with debriding agents that are generally applied and left in-situ to facilitate removal of slough or necrotic tissue.

• Most wound-care experts now agree that the routine use of antiseptic solutions has little place in wound management.
• Antiseptics, particularly those which contain cetrimide, have marked cytotoxic properties and therefore should be avoided unless the wound is contaminated or shows clear evidence of infection.
• For most applications, a sterile solution of normal saline is to be preferred for routine wound cleansing.

Antimicrobial agents - Key features

Antimicrobial agents are used to prevent or combat local wound infection. Numerous preparations are available for this purpose as described in Table 23.

• Antibiotic powders are used mainly in the treatment of infections in superficial wounds although some are also indicated for larger wounds. These products contain neomycin that is known to cause skin sensitisation and there is also a theoretical risk that their application can also lead to the emergence of resistant strains of bacteria. Antibiotic powders should therefore probably be avoided or used with extreme caution.
• Silver sulphadiazine cream is used extensively in specialist centres for the treatment of extensive burns. Because the cream is active against a wide range of pathogenic organisms, it is also of value in the treatment of infected leg ulcers and other wounds.
• Metronidazole preparations. Metronidazole is an antibiotic that is effective against pathogenic anaerobic bacteria often found in necrotic tissue. As such is a useful agent for combating the odour produced by malignant or sloughy wounds[Image-16K].
• Povidone iodine preparations. Povidone iodine is a potent antimicrobial agent that is of value in the treatment of infected wounds[Image-16K]. Like other antiseptics, however, it should not be used once the infection is brought under control for it may have an adverse effect upon wound healing.

Wound debriding agents - Key features

Debriding agents are used to remove slough and necrotic tissue from wounds such as leg ulcers and pressure sores[Image-15K].

• Much controversy surrounds the use of solutions containing hydrogen peroxide and sodium hypochlorite because they are claimed to delay wound healing and may also cause adverse effects upon the surrounding skin. Nevertheless, some practitioners still believe that their short term use may be justified for the cleansing of particularly dirty or sloughy wounds[Image-16K].
• The continued use of enzymatic debriding agents is similarly questioned, for although they have been shown to have some benefit in the treatment of wounds containing semi-liquid slough and purulent exudate, they are ineffective against wounds containing deep hard necroses.
• More wound care experts now tend to rely upon the use of Intrasite gel or hydrocolloid dressings to facilitate autolytic wound debridement.

Miscellaneous products

Cyanoacrylate skin adhesive is used as an alternative to sutures. Proflavine cream is an antimicrobial preparation of doubtful efficacy that has been used for many years to pack cavity wounds and sinuses[Image-15K]. As it also contains lanolin, it can cause skin sensitivity reactions in some patients. Silver nitrate lotion is sometimes used as an astringent antibacterial agent.