Dressing (medical)

# Overview
A dressing is an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm.   A dressing is designed to be in direct contact with the wound, which makes it different to a bandage, which is primarily used to hold a dressing in place.  Some organisations classify them as the same thing (for example, the British Pharmacopoeia) and the terms are used interchangeably by some people.  Dressings are frequently used in first aid and nursing.

# Core purposes of a dressing
A dressing can have a number of purposes, depending on the type, severity and position of the wound, although all purposes are focused towards promoting recovery and preventing further harm from the wound.  Key purposes of are dressing are:
- Stem bleeding - Helps to seal the wound to expedite the clotting process
- Absorb exudate - Soak up blood, plasma and other fluids exuded from the wound, containing it in one place
- Ease pain - Some dressings may have a pain relieving effect, and others may have a placebo effect
- Debride the wound - The removal of slough and foreign objects from the wound
- Protection from infection and mechanical damage, and
- Promote healing - through granulation and epithelialisation

# Types of dressing
Historically, a dressing was usually a piece of material, sometimes cloth, but the use of cobwebs, dung, leaves and honey have also been described.  However, modern dressings  include gauzes (which may be impregnated with an agent designed to help sterility or to speed healing), films, gels, foams, hydrocolloids, alginates, hydrogels and polysaccharide pastes, granules and beads.  Dressings can be impregnated with antiseptic chemicals, as in boracic lint or where medicinal Castor oil was used in the first surgical dressings 
In the 1960s, George Winter published his controversial research on moist healing. Previously, the accepted wisdom was that in order to prevent infection of a wound, the wound should be kept as dry as possible. Winter demonstrated that wounds which were kept moist healed faster than those which were left exposed to the air or covered with traditional dressings.
Ideally, dressings should:
- Control the moisture content, so that the wound stays moist;
- Protect the wound from infection;
- Remove slough;
- Maintain the optimum pH and temperature to encourage healing;

# Usage of dressings
Applying a dressing is a first aid skill, although many people undertake the practice with no training - especially on minor wounds.  Modern dressings will almost all come in a prepackaged sterile wrapping, date coded to ensure sterility, this is due to the fact that it will come in to direct contact with the wound, and sterility is required in order to fulfil the 'Protection from infection' aim of a dressing.
Historically, and still the case in many less developed areas and in an emergency, dressings are often improvised as needed.  This can consist of anything, including clothing or spare material, which will fulfil some of the basic tenets of a dressing - usually stemming bleeding and absorbing exudate.
Applying and changing dressings is one common task in nursing.
An "ideal" wound dressing is one that is sterile, breathable, and encourages a moist healing environment.  This will then reduce the risk of infection, help the wound heal more quickly, and reduce scarring.