According to statistics, 40% of patients of surgical departments in Russian hospitals are individuals with wounds. In this regard, wound dressings are one of the most important groups of medical devices, circulating on Russian market.
Application of modern wound dressings is based on “moist wound healing”. Moist abacterial environment is optimal for the normal cell proliferation in the wound and ensures high activity of wound proteases (enzymes, responsible for the fast purification of wound surface). Moreover, moist environment prevents drying of nerve terminals effectively reducing pain.
Wound dressings can be classified by their structure:
These dressings consist of transparent thin polymer sheet with the adhesive on one side. There are simple wound dressings and dressings containing pharmaceutical substances. Thus, some “active” film dressings contain: silver or 5% solution of chlorhexidine acetate, ensuring antibacterial properties of the device.
This type of wound dressings is used for the pure wounds with the low or moderate exudation.
Hydrocolloids are available in the form of sheets and amorphous mass. Sheets usually look like sponge or film which becomes gel able to absorb exudate after the contact with the wound surface. These dressings are applied for the wounds with low or moderate exudation.
Alginates are biodegradable wound coverings obtained from the seaweeds. Alginates consist of calcium alginate (insoluble in water) which turns into soluble natrium alginate after the interaction with the exudate and forms gel. This gel becomes optimal environment for the proliferation and migration of epithelial cells. This fact explains wound healing properties of alginates.
3.Collagenous wound dressings.
Collagenous wound dressings are used when it is necessary to stimulate the growth of granulation tissue and epithelialization and when other drugs and devices turned out to be ineffective. The mechanism of collagen action on wound healing is connected with its stimulating effect on proliferation of fibroblasts and the ability to develop soft gel on the surface of wound, which is the optimal environment for reproduction and migration of wound cells.
4.Hydrocellular wound dressings.
The main component of hydrocellular wound dressings is a sponge made of synthetic material. Usually it is a foam from polyurethane or silicone. An extensive system of pores allows hydrocellular dressing to absorb and to drain wound secretions, which evaporates into the environment from the outer part of the dressing. Due to their high absorbent properties and ability to evaporate absorbed moisture hydrocellular dressings can absorb large amounts of wound secretion. Therefore, they are indicated for the treatment of wounds with medium and strong exudation.
Hydrogel dressings consist of polymers with hydrophilic centres, so that they are able to absorb and hold within its structure a significant amount of water. The main purpose of the hydrogels is to hydrate the wound surface, thereby stimulating autolysis of necrotic tissue and protecting the growing granulation and epithelium from drying out. This is true primarily for “dry” ulcers with obliterating atherosclerosis.
6.Atraumatic wound dressings.
Atraumatic wound dressings look like a mesh or a perforated film. Atraumatic mesh dressings can be made of gauze impregnated with a hydrophobic compound (paraffin wax, petrolatum, lanolin, triglycerides of fatty acids, etc.). Some of atraumatic wound dressings contain pharmaceutical substances (e.g. antibiotic fusidate sodium). They perform a dual role. First, due to the fact that these dressings adhere neither to the wound surface nor to the secondary absorbent bandage, its change takes place smoothly without damaging the granulation and epithelial cells. Second, the coating containing pharmaceutical substances increase the efficiency of the secondary dressing.
Dressings of this type usually consist of three layers. The first one is a soft layer made of nonadhesive and permeable for wound secretion material. The second one is a absorbing strip and the third (outer) layer is a water-repellent semi-permeable coating. Absorbing wound dressings are used at all stages of wound process. They can be applied individually or in combination with other dressings like a secondary coating. Absorbing wound dressings are usually combined with hydrocolloid pastes, collagenous dressings or ointments.
There are also combined wound dressings which marry properties of, for example, alginates and hydrocellular dressings.
Thus, such a wide variety of wound dressings testifies to the significance of wound treatment and the importance of these medical devices on Russian and world market.