Classification and wound healing phases
European Centre for Long-Term Care
A wound is a skin break, which may extend to deeper tissues and organs. The cause of the wound can be internal and external factors associated with physiological disturbances. The breadth and depth of the wound depends on the causative agent, its strength and areas it affected.
Division of wounds due to the causative agent:
>> exogenous factors:
- mechanical (cut, stab, mashed, gunshot wounds)
- thermal (burns, frostbites)
- chemical (chemical burns)
- electrical (burns)
>> endogenous factors
- ulcers (leg ulcers, pressure sores, diabetic foot) – e.g. impaired circulation
Division of wounds due to the healing time:
- sharp – less than 8 weeks
- chronic – more than 8 weeks
Division of wounds due to the way healing:
- acute wounds – cuts, surgical wounds with even edges and in which there is no substantial loss of tissue. Such wounds are closed with sutures, staples or a dressing, and the wound is healed by first intention and lasts about 6-7 days. It is the most preferred way of healing, and is referred to as primary healing.
- chronic wound – wounds where there is a significant loss of tissue and / or infection. In this case, it is not possible to bring the wound edges together. This type of wound healing by granulation (secondary intention) – the inflammatory phase is followed by proliferative phase, in which the tissue loss is filled with granulation tissue. This process is called secondary healing.
Secondary wound healing concerns chronic wounds – including bedsores, ulcers, and complicated wounds caused by exogenous factors, such as complex surgical wounds. There are three phases in this healing:
- inflammatory phase (purification)
- proliferation (granulation)
The inflammatory phase is characterised by an inflammatory reaction and pain. The body is trying to destroy the bacteria that get into the wound after the discontinuation of the skin. Exudate appears. The dead tissues are excreted out or absorbed by the organism. The wound gets covered with blood clot, which protects it from germs.
In the proliferation phase the exudate is reduced, vessels get narrower, and this is followed by granulation – filling the tissue loss and epithelialisation – the wound is covered with new epidermis.
In the maturation phase the rebuilding process of the newly healed wound takes place to get the strength similar to the intact skin.
The process of healing and its duration depends on many different factors: the general condition of the patient: the age, nutritional status and co-existing diseases; the type of the injury, its location, its closure way, its cleanliness and the time that has passes since the injury to its dressing.