Burns

Burns

A burn is tissue damage caused by intense heat, chemicals, electricity, or radiation that kills cells and denatures cell proteins. The leading causes of accidental death are burns. They may occur because of fires, UV radiation, hot water, spills, radiation, strong acids or bases, or electrical shock. Burns may cause death as a result of fluid loss, infection, and the toxic effects of burned tissue known as eschar. A severely burned patient often dies from dehydration and electrolyte imbalance, which lead to renal failure and circulatory shock. Immediate intravenous infusion of lost fluids is required to save the lives of these patients.

In a burned adult, fluid loss volume is estimated by using the rule of nines, which assesses the percentage of the overall body that has been burned. The body is divided into 11 areas that basically each account for 9% of the overall body area, with an additional area accounting for the genital area (1%). TABLE 6-1 summarizes an estimation of body burns by using the rule of nines. To allow for tissue repair and replace lost proteins, the burn patient requires thousands of daily food calories that are in excess of normal caloric requirements­. This is provided by supplementary nutrition via intravenous and gastric tubing. Once stabilized,­ the next concern is infection. Widespread bacterial infection (sepsis) is the primary cause of death in burn victims. Although burned skin remains sterile for 24 hours, the destroyed skin barrier can then be easily penetrated by many different pathogens, which multiply quickly in this nutrient-rich environment. The immune system, by this point, has also become deficient.

Burns are classified into three types:

■■ First-degree burns: Involve only the epidermis; sig-nified by redness, pain, and slight edema. These burns heal quickly and usually do not leave scars. Most sunburns are first-degree burns (FIGURE 6-12).

■■ Second-degree (partial-thickness) burns: Involve the epidermis and dermis but leave some of the dermis intact; they may appear red, tan, or white with blisters. Second-degree burns are very pain-ful, are slow healing, and may leave scars. Serious sunburns and many scaldings are second-degree burns fIGURE 6-13).

■■ Third-degree (full-thickness) burns: The epidermis and dermis are completely destroyed, and deeper tissue may even be damaged; the skin can repair itself only from the edges of the wound. These burns often require skin grafts, and if left to heal on their own may result in abnormal connective tis-sue fibrosis and severe disfigurement (FIGURE 6-14).

Burns are considered critical if over 25% of the body has second-degree burns, if over 10% of the body has third-degree burns, or if there are third-degree burns on the face, hands, or feet. A facial burn may include burning of the respiratory passageways, causing swelling and suffocation. Burned joints of the body can result in debilitating scar tissue, preventing mobility.

1. Is sunburn usually an example of a first-degree, second-degree, or third-degree burn?

2. List the main causes of burns.