Chapter 9 Burns
PATHOPHYSIOLOGY
Burns are the tissue damage that results from contact with thermal, chemical, electrical, or radiation agents. Thermal burns are the most common type of injury. A thermal burn occurs when the skin is damaged by heat. Tissue under the skin may also be damaged. Chemical burns occur upon contact with acid, alkali, or organic compounds. Electrical burns occur upon contact with high- or low-voltage electricity. In children, this contact is most often with electrical cords. Radiation burns are least common and are infrequent in children. Burn severity is determined by (1) the depth of burn injury, (2) percentage of body surface area affected, and (3) involvement of specific body parts. See Box 9-1 and Figure 9-1 for descriptions of burn severity and depth.
The severity of the burn determines the degree of change seen in the body’s organs and systems. A thermal injury creates an open wound as a result of destruction of the skin. Following the burn, skin perfusion is decreased as blood vessels are occluded and vasoconstriction occurs. Intravascular volume decreases as fluids are leaked from the intravascular to the interstitial space as a result of increased capillary permeability. Pulmonary injury may occur as a result of inhalation of smoke, steam, or irritants. With a major burn, cardiac output decreases and blood flow to the liver, kidney, and gastrointestinal tract is compromised. The child with a major burn is in a hypermetabolic state, consuming oxygen and calories at a rapid rate. Prognosis is dependent on the severity of the burn.
INCIDENCE
1. Burns are the second leading cause of accidental injury and death in children younger than 14 years of age.
2. Children account for 35% of all burn injuries.
3. Mortality from burns is 2500 children annually; 10,000 experience severe permanent disability.
4. Toddlers account for 85% of children with burn injuries.
5. Burns caused by scalds are the most common and usually occur in the kitchen or the bathroom.
6. Electrical and chemical burns are common in the toddler age group.
CLINICAL MANIFESTATIONS
The following are initial manifestations of second to third degree burns over more than 20% of the body surface area:
LABORATORY AND DIAGNOSTIC TESTS
1. Complete blood count—decreased
2. Arterial blood gas values—metabolic acidosis (decreased pH, increased partial pressure of carbon dioxide [PCO2], and decreased partial pressure of oxygen [PO2])
