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A burn is a tissue injury resulting from exposure to flames or hot liquids, contact with an electric current" (ABLS, 1995). Extreme cold can also cause a similar injury referred to as frostbite. Although burn injuries can involve destruction of muscle and bone when severe, these injuries most commonly affect the skin.
The Skin is the largest organ of the body. It is composed of two layers, the epidermis and the dermis and provides at least four functions critical to survival. First, it prevents the loss of body fluid. This function is essential to prevent dehydration. Secondly, it protects the body against infection and injury by providing a physical barrier to repel bacteria and other organisms. Body temperature regu~lation is another very important purpose the skin performs by increasing or decreasing the amount of water excreted by the sweat glands. And lastly, the skin provides sensory contact with our environment which tells us whether we are feeling a light touch, pressure, pain, heat, or cold. Damage that is extensive enough to interfere with these ~funcitons or with those of any other body systems are serious and can be life threatening. The skin also secretes oi~is to soften and lubricate, makes Vitamin D, and identifies us each, individually, by colour and texture. While loss of these functions may not result in death they are very significant and often complicate recovery from a burn injury.
The severity of a burn is determined by assessing the depth and the extent of the injury. Depth is dependant upon how hot the thermal energy and how long it has been in contact with the skin. Temperatures at or below 111 degrees F (44 degrees C) can be tolerated for extended periods of time but tissue damage will occur proportionately in temperatures that are any higher. Because their skin is thinner, children and the elderly are much more sensitive. A good example is that at 140 degrees F (60 degrees C) tissue destruction occurs in fewer than five seconds in children. This is the common setting for home water heaters.
Burn depth is classified as first, second, or third degree now more commonly referred to as partial or full thickness burn injuries. First degree burns are red and sensitive. Sunburn is an example. Second degree burn injuries involve the epidermis and part of the dermis and the skin is red, blistered, and swollen. These two types of injuries are referred to as partial thickness. Third degree burns (full thickness) destroy both layers of the skin and the structures within them such as sensory nerves so that there is no sensation in that area and it appears white or charred.
The extent of the burn is the second factor that must be considered when deciding on the severity of the injury. Medical personnel gauge the extent of the burn by using a formula which divides the body into percentages. This formula is called 'The Rule of Nines' and is used to provide an initial estimate of the extent of burn injury.
It is crucial to determine depth and extent as how and where the injury must be treated is based on this information. Other factors that must be considered include the presence of injury to the lungs, past medical history, and the location of the burns (such as facial or hand burns). Large, severe injuries, those that will affect function, or those that have complicating factors such as inhalation injury require admission to a burn centre.
Now that you have learned what a burn is, the next topic will be what to do in an emergency for a burn at home. First aid to stop the burning process will often determine how severe the burn will be and therefore is a crucial first step in treating a burn injury. Look for this discussion in the next newsletter.
Lois L. Budd
Acting Nurse Manager, Burns and Plastics Unit, VHHSC
