Learning Objective

• Study of surgical dressings
• Desirable features of a surgical dressing

Surgical dressings are mainly applied on the skin in case of injury or wounds. During any damage to the skin, the wound gets plugged with a blood clot, which is a form of natural first aid that prevents any further loss of blood or damage to the injured part. The skin is then repaired by the formation of fibrous and vascular tissues and migration of epidermal cells from the edges of the wound to cover the granulation tissue. This natural mechanism of the skin is sometimes impeded by infection of the wound by pathogens or repeated abrasion of the new epidermis. The outermost layer of the skin is composed of dead, dehydrated and keratinized skin. For proper dehydration and keratinization, evaporation of water is essential.

Surgical dressing or curatio is a term applied to a wide range of materials used for the dressing of wounds. They are used as coverings, absorbents, protective or supports for injured or diseased tissues.

Keeping in mind the nature of skin and the mechanisms involved in the repair of a damaged skin, the following features are required for an ideal dressing:

1. Should be water permeable in order to allow evaporation of sweat and exudates from the injured tissue
2. Should allow easy movement of the joints
3. Should be made up of a nonirritant material and should not induce any hypersensitivity reactions
4. Should be absorbent in nature, in order to absorb any fluids or secretions
5. Should not stick to granulating surfaces and the pore size should be less than 8 µm in order to prevent penetration by capillaries
6. Should provide an effective barrier for microorganisms and should be readily sterilized
7. Should have sufficient tensile strength
8. The physical properties such as tensile strength and color should not vary upon normal conditions of storage.
9. Should not have an abrasive surface, which may damage the healing skin
10. Should permit lamination by adhesives when sealing to the skin is desired. It should also be easily removable without skin damage.

Some terms used in connection with surgical dressings

Count: The count of a yarn is the number of hanks, each of a specified length, in one pound, and is therefore a measure of its fineness. A hank of cotton measures 840 yards and that of wool 560 yards.

Crepe weave: This produces an elastic effect due to the fact that alternate threads in the fabric are highly twisted in opposite directions.

Fast edge: The edge is woven in such a way that it prevents threads from becoming loose.

Fillers: These are substances such as china clay added to the fabric in order to give it a desired finish or appearance.

Moisture regain: This is the difference in moisture content between dried material and material under standard humidity conditions.

Nap: This is the soft, fluffy surface on a fabric produced by mechanical brushing so that the ends of numerous fibers are exposed.

Neps: These are small knots on fibers caused by uneven growth or formed mechanically in processing.

Plain weave: This is a weave in which the threads pass alternatively over and under the threads running at right angles.

Plasticizers: These are substances (solvents) giving plasticity or fluidity to a rubbery mass.

Raised fabric: This is a fabric on which a nap has been produced.

Selvedge: This is a fabric edge so woven that it is fast, that is, the threads do not become loose.

Slubs: These are the thick soft parts of a yarn.

Snarls: These are loops protruding from the fabric due to insufficient tension on the yarn in weaving.

Staple: This is an alternative term for fiber.

Tackifiers: These are resins, both natural and artificial, used to give adhesiveness to a rubbery mass.

Tissue: This is a dressing composed of a layer of fibers, such as cotton wool, enclosed in gauze.

Twist: This refers to the direction of twisting the fibers in spinning yarn. The effect may be intensified for special purposes. For example, in crepe bandage, twist to the right and left is described as ‘Z’ and ‘S’ twist, respectively.

Union fabric: This is a fabric composed of two kinds of yarn, for example, wool and cotton.

Warp: This is the yarn running the long way of the fabric.

Weft: This is the yarn running across the fabric.

Yarn: This is the thread spun from the fibers.