Overview and Risk Factors
Burn injuries are among the leading causes of accidental death. Every year, more than 1 million people in the United States suffer burn injuries, and approximately 50,000 require hospitalization. Hospital stays may be long-term and may involve multiple surgical procedures.
Burns can result from thermal, chemical, and electrical injuries. Each type is treated differently, as described below.
Serious burns are complex injuries affecting skin, muscles, tendons, bones, nerves, and blood vessels. Skin damage impairs the body's normal fluid and electrolyte balance, thermal regulation, and ability to fight infection. Long-term effects include diminished muscle and joint function, and impaired manual dexterity. Involvement of the respiratory system can lead to airway obstruction and respiratory failure and arrest. Burns can also cause permanent disfigurement and concomitant sexual and psychological problems.
African American children in Ohio had nearly 8 times the burn risk, compared with white children in a recent study.1
Additional risk factors include:
- Use of wood stoves.
- Exposed heating sources or electrical cords.
- Unsafe storage of flammable or caustic materials.
- Careless smoking. Cigarettes are the leading cause of house fires.
- Water heaters set above 120°F.
- Microwave-heated foods and containers.
- Age. Children under 4 are at particular risk, especially those who are poorly supervised.
- Gender. Males are more than twice as likely to suffer burn injuries.
- Substandard or older housing.
- Substance abuse. Use of alcohol and illegal drugs increases risk.
- Absent or nonfunctioning smoke detectors. The presence of a functioning detector decreases risk of death by fire by 60%.
A detailed history will assess the mechanism, duration, and timing of the burn. Physical examination will ascertain burn location and severity, and check for dehydration, disfigurement, and infection. Biopsy is rarely needed to verify infection. Even minor burns can exacerbate such diseases as diabetes, hypertension, and cardiac disease. Fires in enclosed spaces should raise the suspicion for smoke-inhalation injury. Clinicians should also be attentive to injuries that suggest physical abuse.
Burns are classified based on the depth and extent of damage, degree of pain, and swelling.
First-degree burns affect only the epidermis and are characterized by erythema or discoloration, mild swelling, and pain. Sun overexposure is a common cause. Injuries heal in 3 to 6 days.
Second-degree burns affect the epidermis and various portions of the dermis, causing a red or mottled appearance and blisters. Fluid is lost through damaged skin, and the burns are painful and tender since nerve endings are still intact. These burns will blanch with pressure. Injuries heal in 1 to 3 weeks or more. Scarring is uncommon, but there can be long-term skin color changes, although most color changes fade over time.
Burns that penetrate beyond the epidermis and dermis are classified as third degree (affecting fat), or fourth degree (affecting muscle, tendon, and bone). Injuries may have a charred appearance and contain white, brown, or black patches. Occasionally they appear red, but will not blanch with pressure. Patients may experience severe pain, but the burns are often not tender, as cutaneous nerve endings have been destroyed. However, partial-thickness burns often surround full-thickness burns and will be painful. Healing occurs only at the wound edges, and scarring is significant, unless skin grafting is done.
Burn patients require specialized care and support. The American Burn Association estimates the level of care required for burns according to the location, depth, and percentage of total body surface area (TBSA) affected.
The types of burn cases that should be referred to a burn unit include:2
- Partial-thickness burns covering more than 10% TBSA.
- Burns involving the face, hands, feet, genitalia, perineum, or major joints.
- Full-thickness burns.
- Electrical burns.
- Chemical burns.
- Inhalation injuries.
- Patients with preexisting medical disorders that could complicate management or recovery.
- Patients with concomitant trauma (such as fractures) in which the burn injury poses the greatest risk of morbidity or mortality.
- Patients who will require special social, emotional, or long-term rehabilitative intervention.
Immediate care can be lifesaving. Before burns are treated, the burning agent must be prevented from inflicting further damage. Materials such as melted synthetic shirts, hot tar, or chemicals should be immediately removed, or, in some cases, chemically inactivated (eg, hydrofluoric acid).
Burns should be thoroughly cleaned (under local anesthesia if necessary) to prevent infection, and sterile dressings should be applied. Tetanus vaccination and analgesics may be administered as needed.
Superficial minor burns should be immersed immediately in cool water if possible, or a cool moist cloth can be applied until pain subsides. Very cold water and ice should not be used, as these may damage skin. Once a minor burn is completely cooled, a fragrance-free lotion or moisturizer can be applied to prevent drying. Additional topical treatments may also be helpful. Aloe vera gel may achieve more rapid healing, compared with petroleum jelly.3
Blisters should be left intact only if they are smaller than 2 cm. Inflammatory cytokines delay healing in larger blisters. Dead skin, broken blisters, and blisters larger than 2 cm should be debrided and cleaned regularly to prevent infection.
Partial-thickness burns are the hardest to evaluate. Depending on the depth, these burns can be treated with Bacitracin ointment, collagenase ointment, silvadene cream, artificial membranes, or surgery. In general, the best cosmesis will result from conservative care.
Elevation of the burned area above heart level aids healing. Physical and occupational therapy may be needed to prevent joint immobility caused by scarring from moderate burns.
Surgery is usually required for full-thickness burns; debridement with skin grafting is indicated when muscle, tendon, and bone are affected.
During the first hours after a major burn, massive capillary leakage may result in profound shock if not treated. Most burn surgeons begin fluid resuscitation using the Parkland Formula. Burns can be better assessed if they are not covered with cream. Therefore, major burns are best dressed with dry gauze only, before transferring the patient to a burn unit.
Large doses of narcotics and anxiolytics may be required to keep the patient comfortable. Often, promotility agents, stool softeners, or cathartics are needed to maintain bowel function. An insulin drip may be necessary to prevent hyperglycemia.
Also, beta-blockade with propanolol and anabolic steroid support with oxandrolone can decrease muscle wasting and weight loss due to hypermetabolism.4
In addition, an escharotomy (which involves cutting through burned tissue until healthy tissue is reached) may be needed to allow chest expansion or to release fluid buildup that can cause loss of blood flow to limbs in circumferential burns.
Inhalation burns are identified by the following triad:
- The patient was in an enclosed space with the fire.
- Carbonaceous sputum and singed oropharynx are present.
- Elevated carboxyhemoglobin is detected by arterial blood gas analysis.
Inhalation injuries are frequently accompanied by carbon monoxide poisoning and require hospitalization. Other substances in smoke that can cause breathing problems include benzenes, aldehydes, ammonia, acrolein, nitrogen oxide, and hydrogen cyanide produced by burning wool and plastics.
Superheated steam or gas causes airway edema or bronchospasm resembling an asthmatic attack. In time, this can lead to acute respiratory distress syndrome (ARDS), which is often lethal.
With chemical burns, it is imperative to identify the source, ascertain whether the agent has been ingested through inhalation or swallowing, and determine the duration of contact. Health care workers must observe universal precautions to avoid exposure.
Most chemical burns can be treated with copious water irrigation. However, chemicals can complicate care through metabolic derangement and respiratory failure. Forced emesis can further injure the esophagus and lungs.
A burn center or poison control center can provide useful information on treatment of chemical burns.
Any electrical injury requires a call to a burn center. Electrical injuries damage multiple organs, including the nervous, cardiovascular, visual, and musculoskeletal systems. Two different types of electrical injuries are caused by direct and alternating current.
The most common direct current electrical injury is lightning, which is nearly always fatal. When the patient survives, trauma injuries from muscle contractures and from the patient being thrown are common. Urinalysis or serum creatine phosphokinase (CPK) can help rule out myoglobinuria or rhabdomyelinolysis.
Injuries from alternating current arise from domestic or industrial wiring and can be classified as low or high voltage (>1,000 volts). The entire body is subjected to its effects, with no entrance and exit points.
Any electrical skin burns should be regarded solely as contact points. Contact points are often full-thickness burns that need referral to a burn center. Most of the damage is underneath the skin, as the current courses through muscles, nerves, blood vessels, and the periostium. For example, patients may lose most of their forearm musculature, despite an initial clinical exam showing only a small palmar contact point. Compartment syndromes are common and must be treated aggressively. Urinalysis or serum CPK measurement should be performed, and referral to a burn center is strongly advised.
Nutritional support is a key component of burn care. Elevations in metabolic rate ranging between 118% and 210% of that predicted by the Harris-Benedict equation occur in adults with a burn covering 25% of TBSA. Resting metabolic rate (RMR) is approximately 180% of basal rate during acute admission in these patients, and their calorie needs may exceed 5,000 kcal/day.5 Patients with a surface burn of 40% can lose 25% of preadmission weight in 3 weekswithout nutrition support;5 losses exceeding 10% are associated with significantly poorer outcome, including impaired immunity and delayed healing.6
Energy and Macronutrient Support
Significant weight loss is preventable with nutritional support. Recommended daily energy intake is as follows:5 for adults, 25 calories per kilogram plus 40 calories per each percent of burn area; for children, 1,800 calories plus 2,200 calories per m2 of burn area. Individualized nutrition assessment is recommended for patients with burns on >20% of TBSA.7
Enteral nutrition support with a high-protein, high-carbohydrate diet is recommended, and timing may be critical. Feedings started within ~ 4 to 36 hours following injury appear to have advantages over delayed (> 48 hours) feedings. If patients are hemodynamically stable (a prerequisite for prevention of bowel ischemia), these benefits include reductions in sepsis associated with gut permeability and clinical infection, as well as significantly shortened hospital stays.8 Enteral support can reduce the burn-related increase in secretion of catabolic hormones and help maintain gut mucosal integrity. The duodenal route is better tolerated than gastric feeding, due to an 18% failure rate in the latter from regurgitation.6 Total parenteral nutrition (TPN) is not recommended, due to its ineffectiveness in preventing the catabolic response to burns.6 TPN also impairs immunity and liver function and increases mortality, when compared with enteral nutrition.5
High-carbohydrate, low-fat diets for burn patients result in less proteolysis and more improvement in lean body mass, compared with high-fat diets,5 and may reduce infectious morbidity and shorten hospitalization time, when compared with a high-fat regimen.7 However, the benefit of a high-carbohydrate formula must be balanced against the risk for hyperglycemia, which can negatively influence the outcome of critically ill patients.6 Nearly all burn patients experience insulin resistance as part of their hypermetabolic response and will need to be placed on an insulin drip to maintain tight control of their blood glucose level.
Protein and fluid needs must also be considered carefully. Protein oxidation rates are 50% higher in burn patients, and protein needs are ~1.5 to 2.0 grams/kg.5 Water loss can be as much as 4 liters/m2/day,5 and a range of 30 to 50 ml/hour is given depending on urine output.9
Additional vitamin-mineral supplements may be indicated. Levels of the fat-soluble vitamins A and E and carotenoids fall below normal in burn injury patients.10 Vitamin E treatment reduced elevation in lipid peroxide levels in burn patients, although improved outcome was not noted as a result.11 Vitamin D synthesis is impaired in the skin of burn patients, both acutely and long-term. Blood levels appear to continue to fall, are below the normal range several years after recovery, and may negatively affect lumbar spine bone mineral density. Consequently, supplementation with the recommended dietary allowance of 400 IU per day has been suggested for patients with significant burns.12
Patients with major burns also suffer acute trace-element deficiencies, at least partly because of large exudative losses through the burned areas.13 A lack of certain trace elements (eg, selenium and zinc) can exacerbate poor immunity, and burns are the second-leading cause of immunodeficiency, after HIV infection.5 Although a role for free radicals and lipid peroxides in burn trauma has been established,14 little research has been done on the effects of antioxidant supplements in human burn injury. However, the addition of selenium, zinc, and copper to a standard trace element formula and enteral nutrition was associated with a significant decrease in the number of bronchopneumonia infections and with a shorter hospital stay.13
The response of burn patients to their nutritional intake should be evaluated weekly or biweekly. However, standard measures of nutritional repletion, such as visceral proteins (eg, albumin, pre-albumin), are influenced not only by nutritional status, but also by inflammatory processes. When low concentrations are observed, the simultaneous concentrations of acute phase reactants, such as C reactive protein, must be compared with their own reference standard to separate nutritional from inflammatory effects.15
Diet: Low-fat, high-protein, high-carbohydrate, enteral tube feedings with appropriate caloric content. Weekly or biweekly assessments of nutritional status.
Nutrition consultation, as appropriate.
Physical therapy, occupational therapy, and mental health consultations, as appropriate.
What to Tell the Family
Burn injury can be very traumatic. It is important for the family to know that the patient may need a great deal of support, especially for deep partialâ€“thickness (2nd degree) and full-thickness (3rd or 4th degree) burns. In severe burns, the patient may be physically incapacitated and emotionally traumatized. In general, a burn patient will be in the hospital 1 to 2 days for each percent of total body surface area burned. The family can play an essential role supporting the patient.
1. Hayes JR, Groner JI. Minority status and the risk of serious childhood injury and death. J Natl Med Assoc. 2005;97:362-369.
2. American College of Surgeons. Resources for optimal care of the injured patient. In: Guidelines for the Operation of Burn Units. Chicago, Ill: Committee on Trauma, American College of Surgeons; 1999:55-62.
3. Visuthikosol V, Sukwanarat Y, Chowchuen B, Sriurairatana S, Boonpucknavig V. Effect of aloe vera gel to healing of burn wound a clinical and histologic study. J Med Assoc Thai. 1995:78:402-408.
4. Pereira CT, Herndon DN. The pharmacologic modulation of the hypermetabolic response to burns. Adv Surg. 2005;39:245-261.
11. Latha B, Babu M. The involvement of free radicals in burn injury: a review. Burns. 2001;27:309-317.
13. Berger MM, Spertini F, Shenkin A, et al. Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial. Am J Clin Nutr. 1998;68:365-371.
14. Horton JW. Free radicals and lipid peroxidation mediated injury in burn trauma: the role of antioxidant therapy. Toxicology. 2003;189:75-88.