Definitions

• In a chronic wound the usual orderly process of healing is disrupted at one or more points, resulting in delayed healing or failure to heal (more than 6 weeks). A wound becomes chronic because of an underlying pathology (e.g. arterial/venous insufficiency, diabetes, etc.) or an external factor (e.g. infection).
• An acute wound follows the orderly process of healing (hemostasis or coagulation, inflammation, cell proliferation, epithelialization and remodeling). Examples of acute wounds are: burns, frostbite, bites, grafts and graft donor areas, deep derm-abrasions, surgical wounds.
• Primary wound dressings are applied directly to a wound and may be active or passive. Passive dressings don’t have an active effect on the wound healing. They are used because of their covering, non-adherent and/or absorbent characteristics. Active dressings have an active influence on the wound healing: they promote and maintain a moist wound environment. They may contain medication.
• Secondary wound dressings are put on top of a primary dressing in order to strengthen it, to make it more occlusive, or to create more absorption capacity.
• Fixation dressing: used to secure the primary and secondary dressing in place, and to support and protect the wound site.
• Compress: Piece of material(s), in any shape, form or size that is used for one or more following purposes: cleansing skin or wound, absorbing body exudate during surgical procedures, use with agents commonly used in wound management, support organs, tissue, etc. during surgical procedure. (according to EN 1644-1).
• Bandage: is wrapping material placed over a dressing or closed skin to hold the dressing , to immobilize a joint or for compression therapy.
• The FDA defines a medical adhesive as “a strip of fabric material or plastic, coated on one side with an adhesive, and may include a pad of surgical dressing...The device is used to cover and protect wounds, to hold together the skin edges of a wound, to support an injured part of the body, or to secure objects to the skin.”

Dressing materials

The most suitable dressing for wound management depends not only on the characteristics of wound but also on the stage of the healing process. The ideal dressing respects moist wound healing principle, removes excess of exudate, adapted to the healing phase, impermeable to micro- organisms, thermal insulation, allows gaseous exchange, conforms to wound surface, non-toxic; induces no allergic reactions, offers mechanical protection, relieves pain, avoids trauma and pain at dressing removal.

Gauze dressings

Gauze wound dressings were made from woven (cotton) or non-woven (cellulose fibers) gauze. Gauze is highly permeable and relatively non-occlusive, they may dry out and stick in the wound bed in wounds with minimal exudate unless used in combination with another dressing or topical agent. Gauze applied directly to the wound has many disadvantages, shedding of fibers (quality of compress) and the leakage of exudate (‘strike through’) with an associated risk of infection.

Gauze may be used as a primary or secondary wound dressing. Woven and non-woven gauze dressings can be used as secondary layers in the management of heavily exuding wounds. According to the absorbent capacity the compresses can be divided in different groups: normal absorbent capacity, the simple woven and non-woven compresses, and the more absorbent capacity: absorbent compresses and the superabsorbent compresses, they contain - next to gauze - also other types of material.

Cotton gauze fabric can be used for swabbing and cleaning skin. Ribbon gauze can be used to pack wound cavities, but adherence to the wound bed may cause bleeding and tissue damage on removal of the dressing (moistening the dressing with saline may help). An advanced wound dressing is often more suitable. Gauze dressings are inexpensive for one-time or short-term use. Gauze dressings come in many forms: squares, sheets, rolls, or ribbons (packing rope).

Paraffin gauze dressing

Tulle dressings are manufactured from cotton or viscose fibers which are impregnated with white or yellow soft paraffin to prevent the fibers from sticking, This is only partly successful and it may be necessary to change the dressings frequently. The wound exudate can be absorbed in the secondary dressing through the holes in the paraffin gauze (this is impeded if more than one layer is applied). Dressings with a reduced content (light loading) of soft paraffin are less liable to interfere with absorption. Paraffin gauze may be impregnated with antiseptic or antibiotic.

Vapour permeable films

They allow the passage of water vapour and oxygen but are impermeable to water and micro-organisms from outside. The sterile dressing can be used as a primary dressing to create/ maintain a moist wound environment in flat, shallow wounds with low to medium exudate. They are highly conformable, provide protection, and a moist healing environment; Transparent film dressings permit constant observation of the wound.

Water vapour loss can occur at a slower rate than exudate is generated, so that fluid accumulates under the dressing, which can lead to tissue maceration and to wrinkling at the adhesive contact site (with risk of bacterial entry). Vapour-permeable films are unsuitable for infected, heavily exuding wounds.

Most commonly, they are used as a secondary dressing over other types of dressing and as a fixation dressing.

Types of bandages

A bandage is a piece of material used either to secure a medical device such as a dressing or splint, or on its own to provide support to or to restrict the movement of a part of the body. Other bandages are used without dressings, such as elastic bandages that are used to reduce swelling or provide support to a sprained ankle. Tight bandages can be used to slow blood flow to an extremity, such as when a leg or arm is bleeding heavily or as compression therapy (e.g. in case of venous leg ulcers).

Bandages are available in a wide range of types, from generic cloth strips to specialised shaped bandages designed for a specific limb or part of the body. Bandages can often be improvised as the situation demands, using clothing, blankets or other material. In American English, the word bandage is often used to indicate a small gauze dressing attached to an adhesive bandage.

Gauze bandage

The most common type of bandage is the gauze bandage, a simple woven strip of material, or a woven strip of material with an absorbent barrier to prevent adhering to wounds. A gauze bandage can come in any number of widths and lengths, and can be used for almost any bandage application, including holding a dressing in place.

Long-stretch or elastic bandages

Long-stretch bandages (LSBs) = bandages for which the extensibility is high: greater than 100% to 120. They contain elastic fibers and may be dry or cohesive (self-adhering bandage or cohesive bandage is a type of bandage that coheres to itself, but does not adhere well to other surfaces).

The elastic behaviour provides constant pressure, which is almost the same at rest and at work, therefore leading to a low static stiffness index (SSI), with little or no massage effect.

This type of action is particularly recommended for immobile or not very mobile patients, incapable of sufficiently activating their calf-muscle pump.

Elastic systems have to be taken off at night since the pressure that they exert is difficult to tolerate when sleeping. The need for re-application every day can sometimes be a significant obstacle in terms of a patient’s compliance with treatment.

Short-stretch or low-elasticity bandages

These bandages are defined as having low elasticity (or non-elastic) if they have an extensibility of less than 100%.

Short-stretch bandages deliver a low resting pressure and a high working pressure (high SSI), producing a significant massage effect on the calf-muscle when the patient is active. This massage effect reactivates the efficacy of the muscle pump by propelling the venous blood flow from the superficial network to the deep network. Short-stretch systems are therefore very effective in the treatment of severe stages of chronic venous disease (CVD), especially in the treatment of venous leg ulcers and severe oedema, since they significantly improve venous return and lymphatic drainage.

They are effective in patients with sufficient mobility and are particularly recommended in the event of severe oedema. They can usually be kept on day and night, due to their low resting pressures.

Tube bandage

A tube bandage is applied using an applicator, and is woven in a continuous circle. It is used to hold dressings or splints on to limbs.

Adhesive bandage

An adhesive bandage, also called a sticking plaster (or simply plaster) in British English, is a medical dressing used for small injuries. An adhesive bandage is a small, flexible sheet of material which is sticky on one side, with a smaller, non-sticky, absorbent pad stuck to the sticky side.

Medical tape

Properties of medical tapes

• The tape needs to adhere to a surface (skin) being shed, a surface that is highly lipid, a surface that is very irregular.
• It has elastic properties.
• Tapes are called pressure sensitive adhesives (PSA): they adhere to the surface best with application of light pressure on the backing.
• Tapes need to be able to handle moisture vapour that normally leaves the skin = MVTR (moisture vapour transmission rate): it depends on the chemical composition of the adhesive, the tape thickness and the permeability of the backing.
• Tape must be non-toxic, hypoallergenic.
• The base of the tape is made of fabric, non-woven, hypoallergenic material or porous plastic.

The ideal tape must be compatible with skin, adhere strongly, be permeable to air and moisture, and remove gently without skin trauma.

Zinc Oxide Tape

Zinc Oxide tape is also known as Strapping Tape or Sports Tape because it is widely used to prevent sports injuries and soft tissue damage. It can also support muscles to stabilise injured ligaments. Zinc Oxide will remain intact when worn for a long period of time, and tolerates moisture, even in humid environments. It is usually made from non-stretch cotton or rayon (woven) with a Zinc Oxide adhesive.

Do and Don’t when using tape

• Consider using a barrier film to protect skin, but avoid alcohol or solvents on neonates
• Avoid substances that are tacky and increase adhesion such as tincture of benzoin
• Do not put tape strips on bed rails, IV trays or any other surface; do not carry rolls in pockets or on stethoscopes to keep tape clean
• Make sure skin is clean and dry before applying tape
• Avoid stretching tape; apply without tension or pulling on underlying skin

Classification of dressings according to European classification rules

Wound dressings may be any class of medical device, depending upon the intended purpose of the dressing, the constituents, how long it will be applied and where on (or where in) the body it is intended to be used.

The majority of wound dressings are non-invasive devices which come in to contact with injured skin:

• Class I if they are intended to be used as a mechanical barrier, for compression or for absorption of exudates (e.g. gauze dressings, absorbent pads, cotton wool)
• Class IIb if they are intended to be used principally with wounds which have breached the dermis and can only heal by secondary intent (e.g. dressings for chronic ulcerated wounds and severe burns)
• Class IIa in all other cases, including devices principally intended to manage the micro-environment of a wound (film, hydrogel, non-medicated impregnated gauze dressings). These dressings have specific properties to assist the healing process by controlling the level of moisture at the wound and to generally regulate the environment in terms of humidity and temperature, levels of oxygen and other gases, pH values, or by influencing the process by other physical means.

Classification is highly dependent upon the manufacturer’s intended use. Example: a polymeric film dressing would be a class IIa if the intended use is to manage micro-environment of the wound and class I if its intended use is limited to retaining an invasive cannula at the wound site.

A claim that a device is interactive or active with respect to the wound healing process usually implies that the device is a class IIb.

Dressings incorporating an antimicrobial agent, where the purposes of such agent are to provide additional action to the wound, are classified as Class III devices.