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Wound Care

The basic function of the wound care materials is providing protection against an infection,

blood and exudates absorption, to promote healing and possibly apply a medication to the

wound [1]. The today available materials range from simple cotton gauzes and lint to

sophisticated multifunctional systems made from natural or synthetic materials [2].

In the history, the development of wound dressings was managed in accordance to personal

experience or historical knowledge. Recently, the development is guided by clinical studies

and evidence based medicine. There have been recognized two wound care systems, these

being traditional and advanced dressing. Their classification includes 10 dressing classes [3].

Gauzes Bio-dressing

Antiseptics Skin derivates

Proteolytic Enzymes Semipermeable Dressings

Absorbents Occlusive Dressing

Granulation Promoters Hydrogels

The materials and designs of wound dressings are derived from the application condition.

These are for the traditional and advanced dressing summarized in Table 1 [3]. It was already

known in the Arabian period that the healing conditions are critical for successful healing

process. The moist wound healing philosophy was scientifically explained in 1960’s in

magazine Nature by George Winter. On the basis of this theory, a new wound care treatment

methods have been developed promoting and respecting the physiological healing process.

Table 1: The functionality of traditional and advanced wound dressings. Traditional dressing Advanced dressing

Exudate absorption and drying of the wound Keep a moist environment

Haemostatis Remove exudates and necrotic tissue

Antisepsis Keep temperature constant

Protection from infection Oxygen permeable

Wound covering Protection from exogeous infection

Easy to handle

Non-traumatic at the dressing change

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The wound dressing materials belonging to the traditional and advanced wound dressings are

designed according to their functionality. They are presented in Table 2 [3].

Table 2: The categories of traditional and advanced wound dressings according to their design

or a material. Traditional dressing Advanced dressing

Gauze Alginates

Lint Hydrogel

Wadding Hydrocolloids

Plasters Foam dressing

Film dressing

The Figure 1 shows the different classes of products; we can highlight that alginates are

positioned in the middle of the two wound care philosophies, because they keep the

microenvironment moist and do not occlude the wound and promote granulation. We can now

analyse the conditions, which advanced dressings produce in comparison to traditional

dressings [3].

Figure 1: Different categories of wound dressings according to use.

Epithelial Cells Migration Under Advanced And Traditional Dressing

The ability to keep a moist microenvironment is important because human cells can only live

in water. The only tissue that can live in the air is that of the skin (keratinised dead cells). The

wound has a superficial loss of tissue and so the structures that need water to live are exposed.

It is obvious then, we need to promote a moist environment to support the healing process.

The second most important condition is that of the length of healing time. Epithelialization

starts from the edge of the wound due to cell migration: keratinocytes need a moist

microenvironment. In a dry wound they will migrate under the dry dermis, but in a moist

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wound they will migrate on the surface, as shown in Figure 2. We can easily understand that a

water mass movement is quicker than that of the removal of dry tissues [3].

Figure 2: Cell migration in a dry and moist wound environment.

Mitosis stops at 32°/33°C and this is the temperature on the wound surface when it is exposed

to air. Dressings made from a fabric cannot isolate the wound but this can be achieved by

using synthetic films because they have a lower thermal conductivity and can be worn over a

longer period of time. This helps to restore the thermal stability lost by the skin.

Prevention of Infection - Comparison Between Traditional & Advanced Dressings

(Hutchinson, mod.)

It’s commonly believed that a moist wound is frequently infected. Hutchinson demonstrated

in a very large number of studies that advanced dressings can reduce the incidence of

infection by more than 50% in comparison with traditional dressings.

The advanced dressings do not adhere to the lesion and so avoid further damage to the wound

or it’s surrounding tissues. The comfort during dressing changes is immediately noticeable

and the creation of a moist, warm environment can reduce pain.

Everyone knows that dressings represent 5% of the management costs of a chronic wound,

whilst 70% of the cost is absorbed by nursing time. It is evident that if dressings worn over a

longer period are used, nursing time can be reduced. This represents a gain, both

economically and in clinical resources [3].

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Traditional Wound Dressings

Examples of available wound dressings according to their origin, functions and applications

are presented in Table 3 [2].

Table 3: Traditional wound dressings. Types Examples Function Form of Application

Traditional

dressings

Cotton

wool

gauze & lint

Allow strike through, shed fibres and

adhere to the wound + dehydrate the

wound

Used on clean, dry wound or as

secondary dressing

Low

adherent

dressing

Cutilin

Melolin

Release

Setoprime

Suitable for dry wounds or lightly

exuding wounds.

Need to be secured with bandage or

adhesive tape.

Some structures of gauze and lint materials are shown in Figure 3. A gauze material is an

open weave, absorbent fabric. When coated with parafin wax, it is used for burns and scalds

treatment.

Figure 3: Examples of gauze and lint structures: A –structure of plain weave, B – real gauze

plain weave, C – structure of leno weave, D – real fabric of leno weave.

A gauze serves as an absorbent material in a pad form (swab) in surgical applications. If yarns

are barium sulphate coated and incorporated into a swab, the material is X-ray detectable [1].

Lint is a plain weave cotton fabric that is used as a protective dressing for first aid and mild

burn applications [1].

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Wadding materials are also used for wound care applications. They are a high absorbent

materials sometimes covered with a nonwoven fabric to prevent wound adhesion or fibre loss

as shown in Figure 4 [1]. The absorbent layer can be made of cellulose pulp, wood pulp, wet

laid cotton or viscose fabrics, etc. Recently the absorbent core can also obtain superabsorbent

polymer powder.

Figure 4: Structure of a wadding material.

More complex wound dressings are composite materials consisting of an absorbent layer

placed between a wound contact layer and a flexible base material, as shown in Figure 5 [1].

The wound contact layer should prevent the adherence of the dressing to a wound and be

easily removed without disturbing the tissue growth. The function of absorbent layer is to

absorb blood or other exudate liquids and provide cushioning effect to protect a wound.

Figure 5: A wound dressing functionality.

The basic textile structures of a wound contact layer are the same as gauze and lint materials

shown in Figure 3. They can be also made of a soft nonwoven spunlaced fabric shown in

Figure 6 [4]. All the fabrics are mostly made of the natural fibres. The recent use of a

collagen, alginate or chitin fibres contribute to the healing process [4].

Some of these articles can be coated by pressure sensitive adhesives which contribute to

wound dressing performance by being stick to the skin around the wound and preventing the

abrasion of wound by the material, therefore damaging of new grown tissue [2].

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Figure 6: E – structure of spunlaced fabric, F – spunlaced fabric.

The absorbent layers are much more the same as those described for wadding materials shown

in Figure 4..

The flexible base materials should protect the surrounding of a wound from leaking of blood

or other exudates leaking. It can be made from a polymer film or porous membranes

permeable to air but not to a liquid.

Examples of a commercially available gauze, lint and wadding pads

ES gauze swabs are the classic swabs made of absorbent cotton

threads [5]. They are highly absorbent, soft, conformable and

permeable to air. They are also available with interwoven Telatrast

X-ray detectable thread under the brand name of "Telacomp ".

They are used for general wound treatment, especially in primary

treatment of dirty, infected or highly exudative wounds, as swabs

and sponges in minor surgery actions.

ES umbilical pads are elastic pads made of absorbent cotton threads. They are soft and

absorbent, used for sterile care of the cord stump in new born babies [5].

PehaSlit Dressing is gauze dressing with the Y slit made of

absorbent cotton threads. A pre-cut, so-called Y slit makes them

suitable for use around rains, in tracheotomies and extensions [5].

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Mulpa is a general purpose gauze swab made of absorbent

cotton specially designed to meet criteria for generally treatment,

especially for larger wounds. They are high absorbent, air

permeable, soft and conformable [5].

Medicomp is a non-woven swab used as an alternative to the

traditional gauze in the ward and in outpatient treatment [5]. It is

made of 70% viscose and 30% polyester fibres. It has an open

gauze-like structure. They are very absorbent, soft and permeable

to air. The non-woven fabric is bonded mechanically and does

not contain binding agents or optical brighteners.

Medicomp® Drain is a non-woven, gauze-structured slit dressings

made of 70% viscose and 30% polyester fibres; free of binding

agents and optical brightening agents, two additional layers for

extra high absorbency, with Y slit [5]. Medicomp Drain non-

woven swabs with Y slits are recommended for use around drains,

in tracheotomies and extensions as well as to offer protection

when cannulae und probes are employed. It is used for the general treatment of wounds; as

swabs and sponges during outpatient and inpatients interventions.

Examples of commercially available wadding pads and wound dressing composites

Eycopad is and eye pad made of absorbent cotton wool with pure

cotton gauze covering. The use of high-quality absorbent cotton

wool and absorbent gauze made of pure cotton makes the

Eycopad eye pad particularly soft and absorbent [5]. The gauze

covering is closed at the narrow sides of the dressing, which

considerably improves cohesion. Eycopad is lint-free and has a

long-lasting, good cushioning effect.

Comprigel is an impregnated, non-adhering gel dressing with an

integrated absorbent core made of a non-woven fabric [5]. This

favourable combination of materials allows both simple and

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effective management of many different kinds of wounds. The wound side of the dressing is

layered with a gel of natural polysaccarides, which is well tolerated by the skin and permeable

to air and secretions. Wound secretions can freely pass through into the absorbent core. The

highly absorbent core is made of a non-woven fabric and possesses a high retention capacity.

Comprigel does not adhere to the wound surface and it keeps wound edges supple. The

gelatinous mass is firmly bonded to the supporting layer made of open-weave cotton tulle,

ensuring that the wound remains clean and the risks of drying out or sticking are reduced.

Comprigel can therefore also be removed painlessly even if the dressing is left in place for

long periods of time. The cooling effect of the gel when applied eases patient discomfort.

The gel layer gives Comprigel slight adhesive properties. It remains in place without any

additional fixation, making its application considerably easier. Comprigel is used for the

general treatment of wounds of diverse origins, on the ward, in general practice and in first

aid.

Fil-Zellin is non-iritant universal dressing for particularly

economical use. It consists a wound compatable nonwoven layer

applied directly to the wound, and several layers of highly bleached

cellulose as the absorbent layer. The dressings are quilted several

times over the entire width to connect the two material layers [5].

The soft, nonwowen wound-contact layer rapidly guides secretions into the absorbent core.

The absorbent core made of highly bleached, creped cellulose layers provides Fil-Zellin its

good absorption capacity. The quilting gives both materials good cohesion, which guarantees

a constantly smooth surface at the wound dressing with no creases.

It may be used universally for wound-compatible treatment of dry or secreting wounds or as

carrier material for ointment and moist dressings.

Zetuvit was specially developed for the treatment of highly

exudative wounds. It consists of four layers of different materials,

which complement each other perfectly to give the dressing pad

its outstanding properties [5].

The covering layer consists of a two-ply non-woven material: The

surface in contact with the wound is made of hydrophobic

polyamide fibres and does not absorb any liquids, thus preventing it from sticking to the

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wound. The inner surface of the non-woven material consists of hydrophilic cellulose fibres

with high capillary activity through which wound exudates can pass quickly to be retained in

the absorbent core. Bleached cellulose tissue disperses the exudates, thereby making full use

of the high retention capacity of the absorbent core. The absorbent core made of soft cellulose

fluff has a high absorption capacity and exerts a good cushioning effect. The backing consists

of a layer of cellulose, which although permeable to air, is hydrophobic and prevents the

exudates from striking through it. Thus the wound is protected against contamination.

It is used for the treatment of highly exudative wounds in all fields of medicine; for

cushioning and protecting wounds.

Grassolind is made of an open weave cotton cloth impregnated

with a non-medicated ointment, which is neutral. It is therefore

especially suitable for the treatment of wounds in dermatology,

for patients with sensitive skin or those who are sensitive to

certain medication and for long-term treatment of wounds with

delayed healing [5].

During all stages of wound healing Grassolind keeps the edges of the wound supple and

protects the wound from drying out. It promotes granulation and re-epithelialization and

effectively prevents undesirable scar tissue contraction. The impregnated dressing does not

adhere to the wound. It can be changed painlessly, granulation tissue and new epithelium are

not irritated. The open weave cotton cloth allows free access of oxygen to the wound and

provides good ventilation. Secretions can drain easily and maceration is avoided.

Grassolind has no sensitizing or allergenic effects even when applied for long periods.

Where necessary, specific topical medication can be added to the non-medicated ointment

base.

It is used for the gentle treatment of large surface lesions, e.g. abrasions, contusions, burns,

scalds, acid burns, radiation damage, etc. In plastic and cosmetic surgery, nail removal,

circumcisions, etc. As a dressing for the donor site in skin grafts and for fixing split-skin

grafts. It is also ideal for the treatment of wounds in dermatology, for patients sensitive to

certain medication and for long-term treatment of wounds with delayed healing, where there

is often the risk of sensitization.

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Atrauman is an ointment dressing that effectively supports all

phases of wound healing. The properties of the cloth used and the

composition of the ointment applied ensure atraumatic wound

care. The thin, soft, open-weave tulle of hydrophobic polyester

fibres with its smooth surface structure counteracts the tendency

of adhesion to the wound by preventing new tissue from

penetrating the dressing [5]. Atrauman's non-adhering properties are enhanced further by the

ointment present in the dressing, thus permitting removal without tissue injury.

Atrauman keeps wound surfaces and edges soft and supple and prevents the wound from

drying out. Undesired contraction of scar tissue is avoided.

The ointment itself is permeable to air and does not inhibit passage of secretions. In this way ,

the wound has sufficient contact with the air and the rapid transfer of excess secretions is

assured. Secretions are absorbed into a secondary dressing applied on top of the Atrauman

dressing. The ointment does not contain added vaseline or other paraffins. No ointment

residues, which are difficult to remove, are produced. The condition of the wound may be

assessed and cleaning of the wound is simplified. The ointment is non-medicated and does not

lead to sensitization. Therapeutically active substances can be applied topically at the

discretion of the physician.

It is used for a traumatic wound treatment in all phases of healing, e.g. for cuts, lacerations,

abrasions, leg ulcers, pressure sores, burns, scalds, acid burns, radiation burns, abscesses,

boils, carbuncles, panaritia; for covering donor and recipient sites in skin grafting, following

plastic and cosmetic surgery, nail extraction, phimosiectomy, etc. The non-medicated

ointment base makes Atrauman also suitable in dermatology and in the treatment of patients

with sensitive skin.

Modern materials are presented by several producers of the wound contact layers [6].

In US patent [7] is described a special wound covering allowing air circulation around a

wound suitable particularly for burns. This function is ensured by a loop (12), shown in

Figure 7, made from a flexible material (foamed elastomeric, or bulky cotton material). A

screen (26), made from air flexible (cotton) in a form of mesh, is attached to the loop and

extends across the opening (24) of the loop.

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Figure 7: Cross section of a wound cover allowing air circulation around a wound.

The screen mesh is fine enough to allow air past through but blocks particles, such as dust. A

panel (28) made from a flexible material is attached to peripheral wall (14) of the loop and

extends along, but does not extend over the opening (24). An adhesive covers the lower

surface (32) of the panel. When applied to a wound, the loop keeps the screen away from the

wound and this prevents the rubbing of the screen on the wound and ensures air circulation

across the wound.

Multi-layer absorbent wound dressing has been developed by 3M [8]. It is designed from

several layers of different functions as shown in Figure 8. A backing layer (20), an adhesive

layer (22), a porous or non-continuous wound contact layer (28) and a pressure sensitive

adhesive (30) are extended along the whole dressing therefore forming a perimeter of non-

absorbent material. Only the first (24) and second (26) absorbent layers are positioned within

the interior of the dressing. These layers are prepared by photo-initiated bulk polymerisation.

The firs absorbent layer is 25 mm thick and comprises of an absorbent composite capable

rapidly absorb moderate to heavy amount of exudates while retaining structural integrity and

transparency. The layer may include: 0-40 parts by weight of an acrylic or methacrylic acid

ester or a non-tertiary alcohol having 4-14 carbon atoms; 30-100 parts by weight of

hydrophilic, ethylenically unsaturated monomer (acrylate and metacrylate esters prepared

from mono-hydroxil-terminated poly lower alkylene oxides, such a PE-, PP-glycols); 0-40

parts by weight of a polar, ethylenically unsaturated monomer (partially neutraliyed acrylc

acid and N-vinyl acetamid), different from the hydrophilic ehylenicaly monomer.

The second absorbent layer is only 3 mm thick and less absorbent than the first one. It may

contain the same componenets but will generally have higher concentration of the acrylic or

metharylic ester monomer. Also one or more multifunctional cross-linking monomers can be

included into absorbent layers.

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Figure 8: Multi-layered absorbent wound dressing article.

An adhesive bandage, with antimacrobial and haemostatic

properties, has been disclosed by Kimberly-Clark [9]. It is

composed from layer an elastomeric layer for covering the

wound and surrounding area (70), as shown in Figure 9,

an adhesive layer (77) for adhering the adhesive bandage

to wound site, an absorbent pad (80) for absorbing

exudates made of a cellulose wadding or a nonwoven,

non-stick perforated cover (85) such as PE film for

allowing limited flow of exudates to the absorbent layer, a

layer of an antibacterial agent and haemostatic agent or a

single wound healing with haemostatic and antimicrobial

functionality (90) coming into contact with the wound.

Figure 9: An adhesive bandage

with antimicrobial and heamostatic

properties.

Cosmopor steril is a self-adhesive wound dressing, which differs

from traditional wound dressings in its novel combination of

materials. It is ideal for postoperative wound management [5].

The main beneficial feature of Cosmopor steril is the water-

repellent microgrid wound contact layer. This allows exudate to pass

quickly into the absorbent pad behind it whilst itself remaining absolutely dry. This prevents

the dressing from sticking to the wound. The dressing can be changed painlessly. The

absorbent pad is made of 100% pure cotton wool, conforms well to the body contours and has

excellent absorbent and cushioning properties. The soft, non-woven support is permeable to

both air and water vapour, thereby ensuring that Cosmopor steril does not interfere with the

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skin's natural functions. The non-woven support has rounded edges which prevent the

dressing from becoming detached even when the dressing remains in place for a long period.

The wide, continuous adhesive border ensures good closure. This, together with the water-

repellent, non-woven covering layer give reliable protection against contamination. Cosmopor

steril is coated with a hypoallergenic polyacrylate adhesive which is very well tolerated by

the skin.

It serves for postoperative wound management and sterile dressing of minor injuries, e.g. in

first aid.

Advanced Wound Dressings

There is a large variability of the materials classified as advanced wound dressing summarised

in Table 4 according to their origin, functional ability and form of applications. The

description of the functionalities of most common dressings from Table 4 [2] are described in

[3] and presented below.

Film Dressings

Film dressings are non-absorbent, permeable to moisture

vapour and oxygen and impermeable to bacteria and

viruses. They are typically made of a thin, transparent

polymer membrane, which is coated with a layer of acrylic

adhesive. Film dressings can be also combined with other dressing materials.

Hydrogel Dressings

Hydrogels maintain balanced hydration through controlled

evaporation. Exudates are absorbed into the gel, moisture

evaporates through semi-permeable film backing or a

secondary dressing.

Hydrocolloid Dressings

Hydrocolloid dressings are backed by either a waterproof polyurethane foam or a thin film. In

some cases, the backing extends beyond the margin of the hydrocolloid to form a border. The

totally sealed hydrocolloid at the wound area keeps the moisture in while keeping the bacteria

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and fluids out. This limits any gas exchange between a

wound and the environment. Fluid absorption is slow

primary trough swelling of particles in the dressing. This

swelling allows a soft, non-adherent gel formation over the

wound.

Calcium Alginate Dressings

The calcium alginates provide a moist healing environment

by converting the exudates into a gel. Reaction between the

calcium in the dressing and the sodium in a wound exudates

results in a chemical ion exchange, which forms a gel-like

substance. The gel conforms to the wound, providing a soft,

moist healing environment. Due to its dehydration effect, this

dressing should not be used with dry wounds.

Foam Dressings

Foam dressings are indicated for a partial thickness or

superficial wounds. The open pore structure of a foam

dressing gives it relatively high moisture vapour

transmission rate. Absorptive ability varies by a

manufacturer. The pore size, texture and absorbency are

controlled by the agents impregnated in the dressing. The degree of occlusion depends on a

presence of a film backing.

Silicon Dressings

A soft silicone dressing is a dressing coated with a soft silicone as an adhesive or a wound

contact layer. The intrinsic properties of soft silicone are such that these dressings may be

removed without causing trauma to the wound or to the surrounding skin [10].

There are different types of soft silicone dressings including a traumatic wound contact layers,

absorbent dressings for exuding wounds and also a dressing for the treatment of hypertrophic

scars and keloids. The soft silicone cannot enter the circulatory system. It is insoluble in

wound exudate and the silicone molecules are too big to penetrate through cell membranes or

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pass through the skin into blood vessels. They therefore cannot be transported around the

body to produce any systemic effects. Soft silicone is not intrinsically absorbent, but it can be

applied as a facing layer to dressings containing absorbent components that are used for the

management of exuding wounds.

Collagen Dressings

Collagen is the fibre forming protein of mammalian connective tissues. It is the major

component of the extracellular matrix forming an organized structure bridging the basal cells

to epidermis. At least 10 different types of collagen have been identified. In the wound

dressing applications, the collagen has haemostatic and absorbent functions [14].

Table 4a: Summary of available advanced wound dressings according to their origin,

functions and applications. Types Examples Function Form of Application

Films Bioclusive

C-View

OpSite Plus

Tegaderm

Vapour-permeable adhesive films,

thin, very flexible, easy to mold

around difficult shapes. They cool the

surface of the wound. Excessive

exudate may accumulate.

Suitable for shallow wounds,. Used to

prevent pressure ulcers and retention

dressing.

Hydrogels Agaflo

GrauGel

Intrsite Gel

Nu-Gek

Sterigel

Hydrophilic polymers, partially cross-

linked to form 3D network. Can

absorb up to 100% if their weight.

Promote moist healing, non-adherent,

by cooling of the wounds surface they

can reduce pain. Amorphous

hydrogels are particularly useful for

treating cavity wounds.

Most require covering with a secondary

dressing, suitable for dry “sloughy”

wounds and lightly exuding wounds.

They are not good for infected or

heavily-exuding wounds. They are also

good for drug delivery such a placental

growth factors and antibiotics.

Hydrocolloids Aquacel

Comfeel

Granuflex R.

Ultec Pro

More complicated than hydrogels,

contain constituets such as

methylcellulose, pectin, gelatin and

polyisobutylene, promote formation of

granulation tissue and provide pain

relief. Suitable for treatments of acurte

and chronic wounds, for desloughung;

light to heavily exuding wounds.

Not suitable for infected wounds,

usually require no secondary dressing,

hence patients can bath and shower.

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Table 4b: Summary of available advanced wound dressings according to their origin,

functions and applications. Alginate

dressing

Algisite M

Comfeel Plus

Kaltostat

SeaSorb

Sorbsan

Natural polysaccharides extracted

from brown seaweed. At

wound/dressing surface sodium-

calcium exchange takes place between

the dressing and the exudates

respectively hence swelling and

formation of gel.

Suitable for use of medium to heavily

exuding wounds and cavity. They are

more used on infected wounds. Most

alginates require secondary dressing.

Foams Avance

Cavi-Care

Flexipre

Tielle

Lyofoam

Polyurethane based, with or without

adhesive borders, main applications

are to absorb large volumes of

exudates reducing the need for

dressing changes

Suitable for use on light to medium

exuding wounds

Silicon

dressing

Cica-Care

Mepiform

N-A Ultra

Silgel

Consists of silicon gel, used to reduce

hypertrophic and keloid scarring,

cosmetically acceptable scars.

Gel sheet can be sterilized and are re-

usable.

Collagens Oasis

Opraskin

Promogan

Suabsorb C

Fibre-forming protein of mammalian

connective tissue. It contributes to

differ of wound healing by attracting

granulocytes and fibreblasts into

wounds and reduces wound

contraction, etc.

Collagen is used as haemostat, an

absorbable suture material, artificial

skin, bone filling and wound dressing

De-odoriser

dressing

Actisorb

Silver

220

Carboflex

Denidor

Metrotop Gel

Contain activate charcoal responsible

for reduction of offensive odours.

Suitable for discharging, purulent and

contaminated wounds complicated by

bacteria infection. Can contain silver

to inhibit bacterial growth.

They are used once or twice daily as

necessary.

Non-adherent

dressing

Available non-impregnated or

impregnated and discourage foreign

matter from becoming lodged in the

wound bed. They can be used on skin

tears, donor site and skin grafts.

Most non-adherent dressings require a

cover bandage or tape to hold them in a

place.

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Examples of film wound dressings

Hydrofilm is a self-adhesive, transparent film dressing that is

indispensable in modern wound management [5]. It gives excellent

protection against secondary infection and offers a number of

additional benefits. Although waterproof and impermeable to

micro-organisms, Hydrofilm does not prevent the passage of

oxygen and water vapour. Thus, it provides an effective barrier for bacteria and germs, but at

the same time does not inhibit cutaneous respiration.This helps to avoid skin irritation in the

area around the wound.

Hydrofilm’s skin compatibility is further enhanced by the use of a

hypoallergenic adhesive which makes it well tolerated even by

patients with extremely sensitive skin. Although it possesses

excellent adhesive properties, the dressing can be removed

painlessly without damaging new epithelium. Hydrofilm is

extremely thin and elastic and adapts perfectly to the body contours. The support material

consists of a resistant protective foil, which makes it easy to apply, even when wearing

gloves. As Hydrofilm is completely transparent, the wound and the sourrounding skin can be

inspected at any time without having to remove the dressing. The same applies when

Hydrofilm is used to secure catheters or cannulae. Hydrofilm is waterproof, enabling the

patient to shower while the dressing is in place. Hydrofilm is particularly useful as a

protective cover against secondary infection or physical damage on dry wounds healing by

first intention and nearly healed epithelial wounds. It may also be used to secure catheters or

cannulae and is ideal as a secondary dressing to cover gel-forming calcium alginate dressings,

e.g. Sorbalgon. It should not be used as a primary dressing on clinically infected, bleeding or

heavily secreting wounds.

Hydrofilm Plus is a self-adhesive transparent wound dressing with

an absorbant pad, which does not stick to the wound. It provides

safe protection of the wound and high degree of comfort for the

patient [5]. The absorbent pad of Hydrofilm Plus has good

absorbent and cushioning properties and is covered with a soft

polyethylene wound contact layer which reliably prevents adherence

to the wound. Although waterproof and impermeable to micro-organisms, the transparent,

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extremely thin Hydrofilm Plus does not prevent the passage of oxygen and water vapour.

Thus, the wound dressing provides an effective barrier for bacteria but at the same time it

does not inhibit cutaneous respiration. The skin compatibility of Hydrofilm Plus is further

enhanced by the use of a hypoallergenic adhesive which makes it well tolerated even by

patients with extremely sensitive skin. Due to the transparency of Hydrofilm Plus, the skin

surrounding the wound and the secretion absorbed by the wound pad can be inspected at any

time without having to remove the dressing. Due to the elasticity of the film, Hydrofilm Plus

adapts perfectly to the body contours thereby guaranteeing a reliable fit.

It is used for postoperative care of slightly secretory wounds, as protection against secondary

infection, as well as for sterile dressing of minor injuries.

Both, Hydrofilm and Hydrofilm Plus are waterproof, enabling the patient to shower while

the dressing is in place.

Examples of hydrogels wound dressing

Hydrosorb is a transparent, hydrocellular gel dressing made of

absorbent polyurethane polymers covered with a semi-permeable

polyurethane film, which prevents penetration of water and

microorganisms. The three-dimensional gel structure of

Hydrosorb has water content of 60 %. Thus, from the very

beginning, Hydrosorb represents a moist dressing with

outstanding biocompatibility [5].

Hydrosorb immediately creates a moist environment and is thus particularly suitable for

treating chronic wounds. It promotes the formation of new tissue during the granulation phase

and maintains a moist wound environment. This is achieved without any risk of wound

exudate accumulating, even during prolonged application. Granulation tissue is prevented

from drying out. During the epithelialization phase, the moist environment created by

Hydrosorb enhances the division and migration of epithelial cells. It also does not stick to

the wound, therefore the dressing may be changed without damaging the new tissue.

As Hydrosorb is transparent, the wound may be inspected at any time without having to

remove the dressing. This considerably reduces the frequency of dressing changes. It is not

dissolved by absorbed wound exudate. Thus it can be removed from the wound in one piece.

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No residues are left on the wound and assessment may be made without prior, time-

consuming rinsing being necessary; unpleasant odours do not occur. The soft elastic

properties of the gel also give Hydrosorb a good cushioning effect.

Hydrosorb has a slight self-adhesive effect. However, for fixation over a longer period of

time, it should be secured additionally with a hypoallergenic strapping tape or a dressing

retention bandage.

Hydrosorb is especially suitable for the treatment of chronic, slow-healing wounds where the

granulation process is not functioning satisfactorily, e.g. in leg ulcers, pressure sores, etc. It is

also used to treat second-degree burns, and to promote re-epithelialization at split-skin graft

donor sites after bleeding has stopped.

Waikatolink presents a honey based wound dressing [11]. The antibacterial nature of honey s

the reason for its potential use as a wound dressing. Honey is modified with a viscosity

increasing agent and is used in pliable or flexible sheets. The incorporation of modified honey

into a gels applied to moist wound dressing is designed to provide antibacterial and anti

inflammatory properties and the promotion of wound tissue growth. The dressing includes

water absorbing, trapping or removing components to assist in the removal of exudates, which

slowly dissolve in body fluids. The article is shown in Figure 10, where suitable material is

embedded with modified honey gel (2l), which is covered by a sheet of gauze (23) and

bonded to a backing sheet (25). The modified honey as ointments or self-adhesive gels are

used on mouth ulcers.

Figure 10: The wound dressing with incorporated modified honey component.

TenderWet 24 is a wound dressing pad, which produces a

"rinsing effect" continuously for up to 24 hours within the wound

[5]. This action exceeds the cleansing mechanisms of other

dressing systems used in moist wound treatment. TenderWet 24

facilitates interactive wet treatment, effectively supporting the

20

spontaneous cleansing mechanisms of the wound, and encouraging the formation of

granulation tissue. TenderWet 24 is a multilayer wound dressing pad containing a

superabsorbent core with irrigating properties as its central component. TenderWet 24

dressings are activated before use with an appropriate volume of Ringer's solution, which is

then delivered continuously to the wound for up to 24 hours. This constant supply of Ringer's

solution actively softens and detaches necrotic tissue. At the same time, the absorbent core

also reliably takes up and retains germ-laden wound exudate. This exchange is possible

because the superabsorbent core has a greater affinity for protein-containing solutions than for

salt-containing solutions. The wound exudate therefore displaces the Ringer's solution from

the dressing pad. Thus, TenderWet 24 continuously renews the film of Ringer's solution in

the wound bed over several hours, and simultaneously absorbs micro-organisms, released

detritus and toxins. Hence, the wound is rinsed and rapidly cleansed.

Furthermore, the physical properties of the superabsorbent compound, combined with the

covering of knitted fabric, give TenderWet 24 a high degree of plasticity. This ensures direct

contact with the wound bed, which is required for fluid exchange to occur.

Moisture and the electrolytes of the Ringer's solution such as sodium, potassium and calcium,

contribute to the stimulation of cell proliferation during the granulation phase. Wet therapy

with TenderWet 24 is indicated especially when wound conditions require active wound

cleansing and supportive treatment, for example in poorly-healing wounds with profuse

exudation; in clinically infected wounds; or in chronic wounds of the most diverse aetiology,

such as diabetic gangrene, pressure sores and leg ulcers. TenderWet standard is indicated for

packing deep wounds. The isotonic TenderWet Solution is available for activation of the

wound pads.

Examples of hydrocolloid wound dressing

Cotoplast Group presents a range of hydrocolloid based wound contact layers that do not stick

to a wound bed [12]. Physiotulle nd Physiotulle Ag are non-adherent, non-occlusive

polyethylene nets with significant absorbency for contact layers, which is a secret to

maintaining the moist environment around a wound.

21

Figure 11: Hydrocolloid based contact layers of Cotoplast Goup.

The netting is coated with Vaseline containing carboxymethylcellulose (CMC). The CMC

absorbs exudates achieving the gelling effect known from using hydrocolloid dressing.

Physiotulle provides faster healing by helping to prevent local infection, the coating ensures

a moist wound healing environment, and the dressing is removable without damaging newly

formed tissue. Physiotulle Ag contains Silver sulphadiazine in addition, which is

homogenously dispersed in Vaseline and provides sustained and controlled silver release. In

contact with a wound, the hydrocolloid particles absorb exudates and silver is released to into

the wound bed and provides faster wound healing by helping to prevent local infection.

Hydrocoll is a self-adhesive, absorbent hydrocolloid wound

dressing covered with a semi-permeable polyurethane layer that

prevents bacterial and moisture penetration. Upon absorption of

exudates from the wound the hydrocolloidal particles swell to

form a gel that expands into the wound and maintains a moist

wound environment. The gel remains absorbent until the

hydrocolloids are saturated [5].

Hydrocoll has a high absorbency due to the presence of

hydroactive colloids. Contaminated exudates are quickly taken

up and securely held in the structure during the swelling process.

During the granulation phase, Hydrocoll enhances the

formation of new tissue by stimulating the activity of fibroblasts,

which are mainly responsible for initiating the process of tissue

regeneration.

Hydrocoll maintains the moist wound environment thus

preventing the granulation tissue from drying out - without the

risk of exudate accumulating in the wound, even during

prolonged application.

22

The division and migration of epithelial cells are supported by the moist environment during

the epithelialization phase. If there are no complications, Hydrocoll can remain on the

wound during this phase for several days until the epithelialization process is completed.

The gel-forming layer prevents Hydrocoll from adhering to the wound. The dressing can be

removed painlessly from the wound without damaging the granulation and epithelial tissue.

Hydrocoll has the ability to adhere immediately, it is flexible and conformable and can thus

be moulded easily onto the body's contours. The bevelled edges help to keep the dressing

securely in place even in difficult areas. The top layer serves as a reliable barrier against

bacteria and protects the wound from contamination and penetration of moisture. Ambulant

patients can shower with the dressing in place.

Hydrocoll is suitable for light to medium exudating wounds, especially in cases of chronic,

slow-healing wounds where healing is delayed and where the granulation process is not

functioning satisfactorily, as is seen with varicose leg ulcers or pressure sores. It is also

indicated for the management of second degree burns.

Hydrocoll sacral is indicated for the specific treatment of pressure sores within the sacral

region; Hydrocoll concave is specially designed for treatment of wounds on the heel and

elbow. Hydrocoll thin, having a lower absorption capacity, should preferably be used during

the epithelialization phase.

Examples of calcium alginate wound dressing

Sorbalgon® is a conformable, non-medicated dressings made of

calcium alginate fibres which form a hydrophilic non-adherent gel

in contact with the sodium salts contained in blood and wound

exudate; the gel fills the wound cavity and creates a favourable

healing condition, drawing bacteria from the wound and keeping

them inside the gel treatment of external wounds of any type;

especially suitable for the treatment of bleeding or secreting wounds, since the gel-forming

properties promote the wound healing process, e.g. venous leg ulcers, pressulre sores,

abscesses, furuncles, burns, difficult wounds following accident or tumour surgery [5].

23

Examples of foam wound dressing

Smit&Nephew produce the range of wound contact layers Proguide

WCL based on Trilaminate Hydrocellular Foam Technology [6].

The dressing is a centrally located highly absorbent hydrocellular

pad, which absorbs and retains liquid in its microscopic structure,

preventing leakage and reducing the risk of maceration of the

surrounding skin. The pad is sandwiched between two perforated non-adherent polyurethane

wound contact layers, which allow even viscous exudate to pass into the dressing. It is

indicated for exudate absorption and the management of partial to full-thickness wounds, can

effectively manage exudate under compression for up to 7 days. It also helps in the creation

and maintenance of a moist wound environment. Moist wound environments have been

established as optimal environments for the management of the wound. It also provides

physical separation between the wound and external environments to assist in preventing

bacterial contamination of the wound.

Syspur-derm is a non-medicated dressing made of two layers of

soft polyurethane foam. Its mode of action and therapeutic

characteristics arise from the different physical structures of the

two foam layers. The open-pored lower layer and the dense, fine-

pored top layer are thermally bonded together without adhesives or

other agents [5].

The open-pored lower layer, which rests on the wound surface, together with the capillary

action of the dense top layer produce a high absorption capacity for exudates. Syspur-derm

thus ensures rapid and intensive cleansing of infected wounds. Necrotic material, cell debris,

pus and micro-organisms are eliminated with the dressing when it is removed.

During the granulation phase, Syspur-derm's open-pored foam layer serves as a matrix for the

development of new tissue und physically stimulates the granulation process. Within a short

time a clean, well-vascularized granulation bed forms as a precondition for spontaneous

epithelialization or successful skin grafts.

The dense, fine-pored, top layer of Syspur-derm has a microporous labyrinth structure which

assumes important physiological properties of the natural skin. It acts as a barrier against

secondary infections, restricts fluid losses and, due to its permeability to gas, ensures the

necessary ventilation of the wound.

24

Syspur-derm is used for the cleansing of all mechanical and thermal surface wounds, e.g.

infected abrasions, second and third degree burns, open fractures etc. It supports the formation

of a well-vascularized granulation bed on cleaned or primarily clean deep and superficial

wounds, e.g. on extensive mechanical lesions, open fractures, following vertical necrectomy,

extensive surgical excisions, etc. It is also suitable for the cleansing of wounds and the

promotion of granulation in cases where natural healing is compromised, e.g. leg ulcers,

pressure sores, radiation ulcers; for the undisturbed re-epithelialization of clean abrasions, for

covering skin graft donor sites, or following tangential necrectomy.

Examples of silicon wound dressing

Cica-Care Gel Sheet is a technically advanced silicone gel sheet for

scar care widely used by dermatologist and surgeons for management of

hypertrophic and keloid scars [13]. It is soft, comfortable and simple to

apply. The skin contact side is self-adhesive while the upper side is

strengthening non-adhesive silicone membrane. The siliscone membrane

and gel comnation akes the Cica-Care durable and less crumble than other silicon sheets.

Examples of collagen wound dressing

PROMOGRAN Matrix combines oxidized regenerated cellulose

(ORC) and collagen [15]. The combination has proved to promote

an optimal healing environment, which is conductive to granulation

tissue formation, epithelialization and rapid wound healing.

PROMOGRAN is used for treatment of diabetic, venous and

pressure ulcers, bleeding surface wounds, traumatic wounds by a

secondary intention, dehisced surgical wounds. The

PROMOGRAN is applied directly on a low exudate wound after

infection treatment. The matrix forms a gel in contact with exudate

or through saline hydration. The matrix is covered with a secondary dressing (type depends on

level and exudates) to maintain a moist wound healing environment.

References

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[1] Horrocks, A.R., Anand, S.C., Handbook of Technical Textiles, The Textile Institute,

2004.

[2] Miraftab, M.: Woundcare Materials: An Overview, Medical Textiles and Biomedical

Healthcare, Woodhead Publishing Limited, Cambridge 2006, ISBN-13: 978-1-85573-683-2,

p. 273.

[3]http://www.tycohealth-ece.com/index.php?folder=65

[4] Medical Textiles, S. Anand, International Conference 1999

[5] http://products.hartmann.info/main.asperl

[6] http://wound.smith-nephew.com/us/Product.asp?NodeId=2847

[7] US Patent 6940000

[8] US Patent 6942628

[9] US Patent 6932785

[10]http://www.worldwidewounds.com/2003/october/Thomas/Soft-Silicone-FAQ.html [11] Medical Textiles, March 2006, pp. 1-3.

[12] http://www.coloplast.com/ECompany/CorpMed/Homepage.nsf/

[13] http://www.nextag.com/SMITH-NEPHEW-Cica-Care-65268260/prices-html

[14] http://www.pjonline.com/pdf/hp/200210/hp_200210_wounds_dressings.pdf

[15]http://www.jnjgateway.com/home.jhtml?loc=USENG&page=viewContent&contentId=09

008b9880edadf1&parentId=09008b9880edadf1