Chapter 45. Burns & Smoke Inhalation

Essentials of Diagnosis

• The ABC's
• Begin fluid resuscitation
• Obtain diagnostic information

See Figure 45–1.

Establish an Adequate Airway

When any patient enters the Emergency Department, the first steps to care involve evaluation of the ABC's—especially in burn patients. Severe burns to the lower face and neck may be associated with upper airway and laryngeal edema that cause airway obstruction. Inhalation of superheated air or steam in a confined space may also cause significant upper airway edema. Full-thickness chest wall burns, especially if they are circumferential, may limit chest wall movement and cause respiratory failure, requiring escharotomy on an emergency basis. Consider early endotracheal intubation in all patients with such injuries and in patients with stridor, hoarseness, or hypoxia.

Airway obstruction may progress rapidly in these patients. When the burn size exceeds 60% total body surface area, early endotracheal intubation should be considered as these patients often deteriorate rapidly. If facial or airway involvement is noted, intubation is advisable. If endotracheal intubation is not successful, cricothyrotomy or tracheostomy may be necessary.

Support Ventilation and Oxygenation

Give oxygen by nasal cannula or face mask. If smoke inhalation may have occurred, give 100% oxygen by tight-fitting reservoir face mask or endotracheal tube. Monitor oxygen saturation by pulse oximetry, but be aware that pulse oximetry readings will be falsely elevated in patients with elevated carboxyhemoglobin levels. Simply subtract the measured carboxyhemoglobin level from the pulse oximetry value to determine the true oxygen saturation. Noninvasive co-oximetry is emerging as a useful tool to monitor the carboxyhemoglobin level in the ED.

Begin Fluid Resuscitation

Patients with deep burns covering more than 15% of body surface area require intravenous fluid resuscitation. Insert one or two large-bore (≥16-gauge) peripheral intravenous catheters, preferably inserted through unaffected skin, or a central venous catheter if peripheral lines cannot be established. Calculation of the percent of body surface burned can be performed using an age-adjusted burn chart displayed in Figure 45–2. Additionally, the “Rule of Nines” can be used to estimate total burned body surface area, with each of the following representing 9%: head, anterior chest, anterior abdomen, each arm, anterior of each leg, and posterior of each leg. The back and buttocks represent 18%, while the groin and each palm represent 1%. Adjustment of the rule of nines for children changes 9% to 5%, with the head encompassing 20% of the total.

Burns are associated with the loss of large volumes of intravascular fluid, electrolytes, and protein through capillaries with increased permeability. Loss begins soon after injury and is maximal during the first 6–8 hours. Currently there is no universal consensus regarding fluid resuscitation and several formulas may be used as guidelines (Table 45–1). Studies comparing colloid to crystalloid solutions for resuscitation have not shown an increased benefit with colloids. Most burn centers today use only crystalloid for the first 18–24 hours, utilizing either the Parkland or modified Brook formula. These formulas should be individualized for each patient on the basis of the patient's response to therapy, as well as the accepting physician's preference if the patient is to be transferred to a burn center. Additional variables including body temperature, blood alcohol level, and inhalational injury may also affect the volume of fluid resuscitation required. In general, infusion rates should be adjusted to maintain urine output at 0.5–1.0 mL/kg/h for adults and 1.0 mL/kg/h for children under 10 kg.

In the case of extensive burns over a significant body surface area, noninvasive blood pressure monitoring may be impossible due to interference of tissue edema with cuff readings. For these patients, a radial or femoral arterial catheter should be placed to accurately monitor blood pressure during resuscitation.

Diagnostic Studies

Arterial blood gas analysis is helpful if respiratory involvement is present. In addition, for assistance in overall patient management and resuscitation, submit blood for carboxyhemoglobin level, complete blood count, and electrolytes and urine for myoglobin. Obtain chest X-ray and electrocardiogram (ECG) and consider obtaining cardiac enzymes in the patient with suspected carbon monoxide poisoning.

Evaluate for Possible Associated Injuries

Burn patients frequently have other injuries in addition to the burn. Patients who have been burned in motor vehicle accidents or explosions should be evaluated as described in Chapter 12. Consider cervical spine and other traumatic injuries in patients who may have jumped or fallen from a burning building or been burned in a motor vehicle crash.

Insert a Urinary Catheter

An indwelling urinary catheter is the most important monitoring device in burn patients to monitor urinary output and to obtain urine for urinalysis (including myoglobin determination if the patient has sustained an electrical burn). Patients with full-thickness burns of the penile glans or shaft may require suprapubic cystostomy.

Insert a Nasogastric Tube

Patients with deep burns covering more than 20% of their body surface will develop an ileus. Inserting a nasogastric tube will decrease the risk of emesis and possible aspiration.

1This chapter is a revision of the chapter by David A. Fritz, MD, FACEP, from 6th edition.

Essentials of Diagnosis

• Evaluate for severity of injury
• Provide wound care
• Transfer to the appropriate facility

Determine the Severity of Injury

Once initial resuscitation efforts have begun, additional information is often required to determine the disposition of the burn patient. Ask the patient, witnesses, and family about the mechanism of injury (eg, explosion, spilled liquid, house fire) and about the possible presence of combustibles known to be toxic. Find out whether the patient was burned in an open or enclosed space; the latter increases the risk of inhalation injury and should prompt consideration of early intubation. Also ask about underlying medical problems, tetanus immunization status, and medication allergies.

An accurate estimate of the severity of injury is crucial in determining the need for hospital admission or referral to a burn center and in guiding initial fluid resuscitation and establishing a prognosis. In general, patients with minor burns may be managed as outpatients, patients with moderate uncomplicated burns should be hospitalized, and patients with major burns should be transferred to a burn center. Even in the absence of major burn criteria, if the hospital does not have facilities or expertise in caring for burn patients, victims with moderate or major burns should be referred to a burn center. The following factors are used to determine burn severity.

Burn Size

Accurate measurement of the burned area, expressed as a percentage of body surface area, should be performed in all burn patients. Burn size may be quickly estimated by using an age-adjusted surface area chart (see Figure 45–2) or by using the “rule of nines” as mentioned earlier in this chapter. The size of scattered small burns can be estimated by comparing them with the size of the patient's hand, which constitutes about 1.25% of body surface area. The extent of all burns should be recorded on a drawing (front and back views) on the patient's chart.

Burn Depth

Burns are typically described as first, second, third, or fourth degree. A more useful description, based on the wound's ability to heal, is partial thickness (heals spontaneously) and full thickness (requires skin grafting). Deep partial-thickness burns usually require grafting to expedite healing and decrease contractures and hypertrophic scar. Figure 45–3 shows the level of skin involved with each type of burn. Table 45–2 outlines the physical findings usually associated with each type of burn. The depth of burn should be recorded accurately on a drawing (front and back views) on the patient's chart.

Several principles must be kept in mind when considering burn depth. First, because it is difficult to distinguish deep partial-thickness burns from full-thickness burns, these burns should be assumed to be full-thickness injuries and should be treated accordingly. Second, burn wounds change over 48–72 hours, and what may appear to be superficial injury on initial examination may progress to a deeper-level injury, especially if the patient has poor perfusion or the wound becomes desiccated or infected.

Burn Site

Burns in the following areas are considered major injuries:

Hands and feet

Deep burns of the hands or feet cause scarring and may produce permanent disability.

Face

Partial- or full-thickness facial burns may cause severe scarring, with profound physical and emotional impact. They are also often associated with inhalation injury and compromised airway.

Eyes

Burns of the eyes may cause corneal scarring and eyelid dysfunction that may ultimately lead to blindness. Note: Patients with possible eye burns should be examined as quickly as possible, preferably in the emergency department, because massive periorbital edema often develops and hinders later examination. Further discussion of eye injury is detailed later in this chapter.

Ears

Deep burns of the ears predispose to development of pressure deformity and infection. Examine the tympanic membrane in patients with external ear injuries caused by hot liquids or chemicals. Burns associated with electrical injury, including lightning strikes, also require examination of the tympanic membrane. A high incidence of rupture occurs with this mechanism of injury.

Perineum

Burns of the perineum are difficult to manage on an outpatient basis and are more susceptible to infection than are other types of burns.

Presence of Circumferential Burns

Any deep circumferential burn is a potential major injury. Circumferential deep burns of the neck may cause lymphatic and venous obstruction that leads to laryngeal edema and airway obstruction. Circumferential burns of the extremities may restrict blood flow, causing an increase in tissue pressure and ischemia. Circumferential chest wall injuries may impede chest wall movement and lead to respiratory failure.

Inhalation Injury

Inhalation injury signifies a major burn. Signs and symptoms suggestive of inhalational injury include burns sustained in a confined space, singed nasal nares, soot around the nares, carbonaceous sputum, hoarseness, stridor, respiratory distress, and a carboxyhemoglobin level >10%. Diagnosis and management of inhalation injuries are discussed below.

Electrical Injury

Damage from electrical injury may be extensive, even though the outward signs of injury are minimal. Cardiac arrhythmias and renal failure from myoglobinuria are possible complications. Electrical currents as little as 100 milliamps can cause ventricular fibrillation. All electrical injuries should be considered major injuries.

Age of the Patient

The mortality rate from burn injury is increased in very young or very old patients; these are also the age groups in which burns most commonly occur. Burns in a child younger than 5 years or in an adult older than 55 years are more likely to be serious than are burns in other age groups.

Associated Injuries

Burns may occur in patients with other injuries, such as fractures or internal injuries due to vehicular accidents, falls, or explosions. The associated injuries often place the patient at increased risk of serious complications or death, even though the burns themselves are small.

Major Underlying Medical Problems

Major pre-existing medical problems in a burn patient are associated with an increased rate of serious complications and death. Any pre-existing condition that prevents normal healing puts a patient with even minor burns at risk for complication. Patients with a history of myocardial infarction, angina, significant pulmonary disease, diabetes mellitus, or renal failure are considered poor-risk patients even if their burns are not serious. Burned patients with a history of alcohol or other drug abuse are also at higher risk for complications following burn injury.

Control Pain

Oral, subcutaneous, or intramuscular administration of narcotic analgesics may provide adequate pain relief for outpatients; however, in patients with moderate or major burn injuries an intravenous opiate such as morphine should be carefully titrated to control pain. Ventilator support may be required in some patients to permit adequate pain control. Recent studies evaluating pain control in burn patients have shown that large amounts of opiates increase the fluid requirements for adequate resuscitation. Fluid volumes should be monitored and adjusted accordingly.

Provide Appropriate Wound Care

Gently remove clothing, dirt, and other foreign material adhering to the burn; irrigation with sterile saline (at room temperature) may be helpful. Do not scrub wounds or use harsh detergents or chemical disinfectants (eg, benzalkonium chloride, povidone–iodine). Little or no debridement of moderate or major wounds should be performed in the emergency department. Redundant skin from ruptured blisters of minor superficial partial-thickness burns may be removed. The wounds of patients with moderate or major burns, especially those who will be transferred to a burn facility, should not be treated with topical ointments or complex dressings in the emergency department, because these will have to be removed for evaluation upon arrival at the receiving facility. A simple nonadherent dressing such as petrolatum-impregnated gauze or sterile saline-soaked dressings should be applied instead. Administer tetanus prophylaxis if indicated. Direct communication with the accepting physician at the burn center can provide specific and individualized instructions for wound care prior to transfer.

Transfer the Patient to a Burn Center

All major burns and many moderate burn injuries are best treated in a burn center, which has the personnel, equipment, and expertise needed to treat major burns effectively. When a patient with a serious burn is first evaluated, the closest burn center should be contacted immediately, so that recommendations for care can be obtained and plans made for transfer, if indicated. If transfer can be carried out quickly, escharotomy may be performed at the receiving facility in patients with circumferential burns of the extremities, chest, or neck and who do not have signs of respiratory compromise or tissue ischemia. Fluid resuscitation and all other supportive measures should be continued during transport, and the patient should be kept warm. See Table 45–3 for treatment and transfer criteria.

General Considerations

Burns that meet the criteria for outpatient management may be treated initially in the emergency department, after which arrangements should be made for close follow-up on an outpatient basis.

Treatment

First-degree burns (erythema only) are best treated with application of nonadherent dressings (eg, petrolatum-impregnated gauze). Clean deeper burns by gently irrigating them with sterile normal saline solution. Studies have shown faster healing of burn wounds by leaving blisters intact, so minimal debridement should be performed. Open blisters can be unroofed with removal of nonadherent epidermal fragments. Wounds may be covered with a topical antibiotic such as silver sulfadiazine cream or triple antibiotic ointment and wrapped in a bulky dressing. Instruct the patient to keep the wound clean and to change dressings and apply topical antibiotic cream twice a day at home. A nonadherent, semipermeable, polyurethane dressing (eg, Epi-Lock), which is left in place for 5–7 days, may be an acceptable alternative for some patients. Such dressings should be covered with roll gauze, which is changed daily. Have the patient elevate affected extremities to minimize development of edema. All patients should receive tetanus prophylaxis. Prophylactic systemic antibiotics are not indicated. Control pain with oral opiate analgesics or a combination of NSAIDs and opiates.

Disposition

Patients should be seen on an outpatient basis in 1–2 days. Ruptured blisters or dead tissue may be debrided at that time. Promptly treat any minor infection with oral antistaphylococcal drugs (eg, dicloxacillin, 250–500 mg orally four times a day, children <40 kg, 25–50 mg/kg/d orally divided into four equal doses; or a first-generation cephalosporin such as cephalexin, 250–500 mg orally four times a day, children, 25–50 mg/kg/d orally divided into two or four equal doses). Patients who develop infections (fever, extensive cellulitis , lymphadenitis), poor-risk patients (diabetics), and unreliable patients must be hospitalized for administration of parenteral antibiotics and continued wound care.

See Figure 45–1.

Essentials of Diagnosis

• Look for evidence of thermal injury (airway edema)
• Consider signs of chemical injury to lung parenchyma
• Evaluate for carbon monoxide toxicity

Thermal Injury

Mechanism

Patients who have been trapped in a fire in a confined space inhale superheated gases and may have thermal injury to the mouth, oropharynx, and larynx. Direct flame injury of the face and neck may also occur and are associated with development of marked upper airway edema and possible airway obstruction. Because of the efficient thermal exchange system of the upper airway, direct thermal injury to the lower respiratory tract is unusual. Rarely, exposure to water or steam in the heated gas mixture may produce thermal damage in the lower trachea and bronchi.

Clinical Findings

Upper airway thermal injury should be suspected in any patient exposed to a fire occurring in a confined location and in patients with obvious neck or facial burns. Soot around the nares, carbonaceous sputum, singed nasal vibrissae, and burned facial hairs are also indicators of thermal injury to the upper airway. Patients may complain of dyspnea; there may be stridor, drooling, or dysphonia. A lack of these findings does not exclude injury. Thermal injury to cutaneous tissues leads to widespread generalized edema which can involve the airway. The diagnosis is confirmed by visualization of the larynx by direct or video-laryngoscopy, or by flexible fiberoptic scope.

Chemical Injury

Mechanism

Chemical injury to the airways and lung parenchyma may be caused by noxious products from combustion of flammable materials (Table 45–4). Some of these products are directly toxic to the airways and lung parenchyma. Only the most commonly produced toxins are discussed below.

Acrolein

Acrolein is a highly reactive aldehyde that results from combustion of wood and petroleum products. It rapidly reacts with lung and airway tissues, causing injury by protein denaturation. Prolonged inhalation or exposure to high concentrations (>150 parts per million) for short periods of time (minutes) can be fatal. Lesser exposure causes pulmonary edema due to alveolar capillary leakage, bronchorrhea and bronchospasm (which may be severe), and ventilation -perfusion disturbances that cause hypoxemia that may persist even after the person is no longer exposed to smoke. Acrolein also causes conjunctivitis and ocular tearing at low concentrations.

Hydrochloric acid

Hydrochloric acid is one of the main products of combustion of polyvinyl chloride, a material commonly found in the structural components of houses and high-rise buildings as well as in furnishings and plastics. Hydrolysis occurs when hydrochloric acid comes in contact with the mucosa of the upper airway and tracheobronchial tree, causing protein denaturation and cell death. Even limited exposure may cause marked ocular irritation and tearing, although individuals with repeated or prolonged exposure may become desensitized to this effect. More severe exposure is associated with dyspnea, chest pain, and irritation of mucous membranes. Onset of pulmonary edema may be delayed for 2–12 hours after exposure, and the patient may appear asymptomatic in the interim. Toxic levels of hydrochloric acid gas may persist for as long as 1 hour after a fire has been extinguished. Patients exposed to products of combustion of polyvinyl chloride may also demonstrate premature ventricular contractions and may be at risk for development of lethal cardiac arrhythmias.

Toluene diisocyanate

Toluene diisocyanate is a product of combustion of polyurethane, a synthetic material found in almost all homes and offices, where it is used in seat cushions, mattresses, and carpet backing. Toluene diisocyanate is also found in insulation material. Toluene diisocyanate may cause severe bronchospasm, especially in persons with underlying obstructive lung disease, and it is also an ocular irritant.

Nitrogen dioxide

Nitrogen dioxide is produced in fires involving automobiles or agricultural wastes. It is an uncommon though important toxin, because even brief exposures to high concentrations may cause severe bronchospasm, laryngospasm, and pulmonary edema. If the patient survives, late development of bronchiolitis fibrosa obliterans and chronic interstitial lung disease may occur.

Other noxious products

Particulate matter in smoke may stimulate irritant receptors in the large airways and cause bronchoconstriction.

Clinical Findings

Chemical injury to the airways and lung parenchyma is difficult to diagnose in the emergency department. Wheezes, rales, rhonchi, and voice changes may be noted or initially absent in these patients. Direct laryngoscopy or flexible fiberoptic bronchoscopy may reveal mucosal friability and edema of the airways. Fiberoptic bronchoscopy is the burn center standard but is limited to upper airway evaluation. Initially the chest X-ray is often normal and serves as a baseline; noncardiogenic pulmonary edema may develop hours after exposure. Xenon lung scans, pulmonary function tests, and nitrogen washout studies have all been used to document the extent of pulmonary involvement but are not commonly available in the ED.

Systemic Chemical Poisoning

Mechanism

Carbon monoxide

(See Chapter 47) The most widely recognized and most common complication of smoke inhalation is carbon monoxide poisoning. Carbon monoxide is a product of incomplete combustion and is produced in varying amounts in all fires. Carbon monoxide binds to hemoglobin with an affinity that is 260 times greater than that of oxygen, forming carboxyhemoglobin. The presence of even small amounts of carboxyhemoglobin drastically alters the affinity of the remaining unbound hemoglobin. Thus, even small concentrations of carbon monoxide may markedly reduce the binding of oxygen to hemoglobin, and the carbon monoxide that is bound is not easily displaced by oxygen. The presence of carboxyhemoglobin shifts the oxy-hemoglobin dissociation curve to the left, making it more difficult for hemoglobin to release bound oxygen to the tissues. The net result is tissue hypoxia and lactic acidosis due to cellular anaerobic metabolism. Carbon monoxide also inhibits mitochondrial function. Brain damage due to excitatory amino acids, inflammation, and oxidative stress may occur. In high concentrations, carbon monoxide is also bound to myoglobin, and may lead to rhabdomyolysis with myoglobinuria and renal failure. The half-life of carboxyhemoglobin is about 4–5 hours, which can be reduced to 60 minutes by administration of 100% oxygen.

Cyanide

(See Chapter 47) Reports have documented the presence of cyanide in the smoke of residential fires. Because of the difficulties in measuring cyanide levels in patients and because of the difficulty in recognizing smoke-related cyanide poisoning, the clinical relevance of cyanide poisoning in smoke inhalation is uncertain. Because there are risks associated with traditional treatments of cyanide poisoning—which involves the production of methemoglobin by infusion of sodium nitrite—in a patient who also demonstrates carboxyhemoglobinemia, this empiric therapy for cyanide poisoning is not recommended. More recent evaluation of newer cyanide antidotes continues to develop. Sodium thiosulfate and hydroxocobalamin have potential as empiric treatments in suspected cyanide poisoning.

Clinical Findings

Carbon monoxide

Systemic chemical poisoning due to carbon monoxide should be suspected in every victim of fire and may be confirmed by measuring the serum carboxy-hemoglobin level. The often-described cherry-red skin color is not a frequent or reliable finding in patients with carbon monoxide poisoning. Similarly, arterial blood gas measurements are not reliable determinants of carbon monoxide poisoning, because PaO2 and the calculated percentage of oxygen saturation of hemoglobin (the value that is routinely reported by clinical laboratories) are not affected by carboxyhemoglobin. The oxygen saturation measured by pulse oximetry does not distinguish oxyhemoglobin from carboxyhemoglobin. Hence, the actual saturation is obtained by subtracting the percent of carboxyhemoglobin from the measured saturation obtained from the pulse oximeter.

Typical nonexposed, nonsmoking individuals may have serum carboxyhemoglobin levels of up to 1%; smokers usually have levels of 4–6%. Levels above 10% signify significant exposure and may be associated with symptoms as outlined in Chapter 47. Patients may be asymptomatic when carboxyhemoglobin levels are below 10–15%. Levels higher than 50–60% are associated with a high incidence of coma and seizures, and levels higher than 70% are frequently fatal. Myocardial ischemia or infarction and cardiac arrhythmias occur frequently, especially in patients with underlying atherosclerotic heart disease. Some patients who initially appear to have recovered may experience delayed onset of a neurologic syndrome characterized by dementia, ataxia, and other sensory and motor abnormalities. This syndrome may be due to infarcts in the globus pallidus. Loss of consciousness may be transitory.

Cyanide

Sustained loss of consciousness, dilated pupils, seizures, and hypotension are findings that are more likely in cyanide poisoning. Tachypnea may be followed by central apnea. Lactate levels correlate strongly with toxin levels.

Treatment

For the critically ill patient, proceed as outlined earlier in this chapter. If there are signs of thermal injury to the airway, endotracheal intubation is indicated. In patients with major burns (particularly greater than 40–60% total body surface area), even if the airway is patent initially, edema frequently occurs minutes or hours later. Prophylactic intubation prevents a subsequent difficult intubation or surgical airway.

Obtain arterial blood gas and carboxyhemoglobin determinations in all patients with possible smoke inhalation. While waiting for the results, give 100% oxygen by tight-fitting reservoir mask or, if indicated, by endotracheal tube. Avoid alkalosis and hypothermia, which decrease the dissociation of carbon monoxide from hemoglobin. Indications for hyperbaric oxygen therapy have been described as a carboxyhemoglobin level greater than 25%, neurologic symptoms, seizures, pregnancy, or depressed consciousness. The efficacy of hyperbaric oxygen in clinical management remains unproved and its use cannot be mandated. Although therapy shortens the half-life of carboxyhemoglobin to roughly 20 minutes, the hazards and the length of time involved in transporting a critically ill patient to the nearest hyperbaric oxygen facility and the limited resuscitative environment of the chamber may outweigh the benefits of treatment. Hyperbaric oxygenation may be useful in the severely poisoned patient who fails to respond to therapy with 100% oxygen. If carboxyhemoglobin levels are under 2% and if oxygenation is adequate, the inspired oxygen content can be decreased. In stable patients with suspected thermal or chemical injury of the airway, evaluate mucosa injury using direct laryngoscopy.

Obtain an ECG, and monitor cardiac rhythm. Carbon monoxide poisoning is associated with myocardial ischemia and cardiac arrhythmias. Obtain a chest X-ray to look for signs of lung injury if smoke inhalation has occurred and to serve as a baseline for further changes. Give inhaled and parenteral bronchodilators to patients with clinical evidence of bronchospasm. Obtain a urine specimen for assessment of myoglobinuria. No evidence supports the use of prophylactic antibiotics or systemic corticosteroids in the treatment of inhalation injuries.

Disposition

Because victims of smoke inhalation may develop late respiratory failure, these patients should be hospitalized for 24 hours for observation. All patients with carboxyhemoglobin levels higher than 25% should be hospitalized. Patients who present to the emergency department with respiratory compromise or respiratory failure should be hospitalized in an intensive care unit.

Chemical Burns

General Considerations

Most chemical burns result from exposure of the skin to strong acids or alkalis. Other chemicals that may cause skin damage include phosphorus and phenol. Because full development of chemical burns is slower than that of other types, the size of chemical burns is usually underestimated during initial evaluation.

Clinical Findings

Definitive diagnosis of chemical burns depends on the history. The physician should try to ascertain both the type of the chemical involved and its concentration. Physical examination of a patient unable to give a history may aid in diagnosis. Alkali burns are frequently full-thickness injuries, appear pale, and feel leathery and slippery. Acid burns are usually partial-thickness injuries and are accompanied by erythema and erosion. Skin is stained black by hydrochloric acid, yellow by nitric acid, and brown by sulfuric acid.

Treatment

The mainstay of treatment of any chemical burn is copious irrigation with large amounts of tap water. To be most effective, treatment should be started immediately after exposure, preferably before arrival in the emergency department.

Remove any contaminated clothing while preventing personnel exposure. Do not attempt to neutralize the burn with weak reciprocal chemicals (acids for alkali burns or alkali for acid burns), because the heat generated from the chemical reaction may cause severe thermal injury. Occasionally the leathery skin of an alkali burn may make it difficult to completely wash away the alkali, and injury may continue; further irrigation and emergency excision of burned tissue by a surgeon experienced in this procedure may be indicated. Typical cutaneous burn care including pain control and fluid replacement should follow. After copious irrigation with water, the following treatment for specific types of chemical burns may be used:

Hydrofluoric Acid

Hydrofluoric acid dissociates into its component ions, and acts more like an alkali—penetrating the tissue to cause liquefaction necrosis. Insoluble salts may also form and further damage tissues. Cover burns with calcium gluconate (2.5%) gel prepared by mixing 3.5 g of calcium gluconate powder in 150 cc of water-soluble lubricant (eg K-Y jelly), secured by an occlusive cover. Remove and rinse the gel after 15 minutes and repeat the process until pain relief is achieved. In fingertip burns, the fluoride ion often penetrates under the nail bed and matrix, so that it is usually wise to remove the nail or make a large wedge. For persistent pain or more severe burns, the treatment of choice is subcutaneous and intradermal injections of calcium gluconate (10%), 0.5 mL/cm2 of burned area by a 30-gauge needle. Larger volumes should not be used, especially in the fingers, because further damage may occur from compartment pressure or the intrinsic toxicity of calcium. Calcium chloride should not be used as it may cause further damage. For extremely severe burns, some physicians recommend intra-arterial perfusion of calcium.

Phenol

After copious high-pressure irrigation with water, enhance the removal of phenol by applying polyethylene glycol, which increases the solubility of phenol. Caution is advised with this practice to avoid spreading the area of exposed phenol. Follow with additional water irrigation.

Phosphorus

Phosphorus, a potent oxidizing agent found in certain types of ammunition, ignites and melts on air contact and often leaves embedded deposits on the skin. Thermal and chemical burns can be present simultaneously. Immersion in cool water is recommended, followed by attempts to remove embedded material. Hypocalcemia and hyperphosphatemia may result after systemic absorption. Telemetry monitoring is necessary in the case of electrolyte derangement until corrected, as bradycardia or other arrhythmias may occur. Previous recommendations were to apply a solution of copper sulfate to inactivate the phosphorus and aid in its removal. However, systemic toxicity including hemolysis, renal and cardiovascular failure from copper absorption may occur and this practice is no longer recommended. The copper is not an antidote or inactivating agent, but turns phosphorous particulate black to aid in removal. A Wood's lamp may be used alternatively to illuminate the particles and aid in their removal.

Fluid resuscitation in the patient with large chemical burns is the same as that for patients with similar-size thermal burns. Because the size of chemical burns may be underestimated initially, reevaluate the patient after 24–48 hours.

Disposition

The choice between hospitalization and outpatient management of chemical burns should be made using the same criteria as for thermal burns. Noting that the full extent of skin injury may not be readily apparent during an initial emergency department evaluation, inpatient observation is frequently recommended for chemical burns.

Tar Burns

General Considerations

Road or paving tar may be heated to 135–149°C for application, and roofing tar is heated to 232–260°C. The hands, arms, head, and neck are the most commonly burned areas.

Treatment

Cool the tar immediately with water, which often separates the tar from the skin. If the tar continues to adhere, either leave it in place or apply one of the commercially available cream- or oil-based solvents specially made for this purpose. Shur-Clens®, triple-antibiotic ointment, and mineral oil are among the many reported options to attempt separation. Do not use hydrocarbon solvents, such as paint thinner or gasoline, because they may further injure burned skin. Cover the wound with sterile dressings. When dressings are changed after 6–24 hours, much of the tar will have separated and will be removed with the dressings. Initial stabilization of the patient with large tar burns should follow the procedures outlined for thermal burns.

Disposition

The criteria for admission or transfer to a burn center for patients with tar burns are the same as for patients with thermal burns.

Sunburn

General Considerations

Most sunburns are first-degree (erythema) or superficial partial-thickness (blisters) burns. Skin changes from sunburn are maximal about 12–24 hours after exposure. Patients usually present to the emergency department for pain relief. Occasionally a patient with extensive superficial partial-thickness burns will require fluid resuscitation and parenteral analgesics for pain control.

Clinical Findings

Diagnosis is based on a history of exposure to the sun (or to ultraviolet light in tanning beds) and physical findings of erythema and blistering.

Treatment

Sunburn can be difficult to treat. Saline-soaked dressings or calamine lotion may provide some relief from pain and itching. Ibuprofen and other nonsteroidal anti-inflammatory agents work by blocking the production of prostaglandins that are thought to be important mediators of pain in sunburned skin. Oral and topical corticosteroids have not been shown to significantly improve symptoms or decrease healing time. Patients with extensive partial-thickness sunburn should receive treatment according to the guidelines described for other thermal burns.

Disposition

Almost all patients with sunburn may receive treatment on an outpatient basis. If there are large blisters, the patient should be seen again in 2–3 days to make sure that secondary infection has not developed. Patients should be advised to avoid prolonged ultraviolet light exposure to the sun in the future and to use a sunscreen (eg, over-the-counter preparations containing PABA [p-aminobenzoic acid] or dioxybenzone) before exposure. Patients requiring fluid resuscitation or parenteral analgesics should be hospitalized.

Electrical Burns

See Chapter 46.

Ocular Burns

See also Chapter 31.

Essentials of Diagnosis

• High level of suspicion in patients with facial burns
• Evaluate for foreign bodies
• Examine eyes with fluorescein

General Considerations

Patients with thermal facial burns may also have burns to the eyelid and the eye itself. Chemical burns constitute one of the most common work-related injuries seen in U.S. emergency departments. Both types of burns may be associated with the development of massive periorbital edema that makes delayed examination difficult. Injury of the cornea or anterior chamber may occur and lead to permanent vision loss. It is therefore important that patients with suspected ocular burns be examined promptly, preferably in the emergency department.

Clinical Findings

Instill tetracaine, 0.5%, or proparacaine, 0.5%, in the conjunctival sac to decrease pain during examination. Systemic analgesia should also be provided when needed. Retract and evert the eyelids to look for foreign bodies. Remove particulates and contact lenses to prevent injury to the cornea due to pressure from edematous lids. Assess visual acuity. Corneal abrasions and thermal injury may be detected by instilling fluorescein in the conjunctival sac and examining the eye using the blue light on an ophthalmoscope or, if the patient's condition permits, a slit lamp. Most ocular burns cause uveitis, and cell and flare in the anterior chamber are apparent. Cycloplegics are indicated to prevent synechiae. Phenylephrine is contraindicated.

Treatment

Irrigate any suspected chemical burn of the eye with large amounts (at least 2 L) of sterile normal saline using a Morgan lens. Tap water and Ringers Lactate are sufficient alternatives. Restoration of physiologic pH is paramount, and irrigation should continue to this end. Treat corneal abrasions and thermal injuries by instilling an ophthalmic antibiotic in the conjunctival sac. Alkali burns cause liquefaction necrosis rapidly, may require larger amounts of irrigating fluid, and require emergency ophthalmologic consultation. 1% calcium gluconate drops should be considered for hydrofluoric acid exposure, but only used after discussion with an ophthalmologist.

Disposition

Burns of the eyes are major injuries. Obtain urgent ophthalmologic consultation.

Circumferential Burns of Neck, Chest, and Extremities

General Considerations

Circumferential deep burns of the neck may cause lymphatic and venous obstruction leading to laryngeal edema and airway obstruction. Circumferential chest wall injuries may impede chest wall movement and lead to respiratory failure. Circumferential burns of the extremities may restrict blood flow, causing increased tissue pressure with resultant ischemia. Scarring can also restrict range of motion and affect fine motor function.

Clinical Findings

Patients with deep circumferential neck wounds should undergo direct visualization of the larynx by laryngoscopy. Because laryngeal edema may develop hours after initial examination, frequent reevaluation may be necessary.

Monitor patients with circumferential chest wounds for signs of respiratory compromise (tachypnea, dyspnea, deteriorating arterial blood gas levels); measurement of forced vital capacity or peak airway pressure may be useful.

Carefully examine the extremity distal to the wound in patients with circumferential burns of the extremities. Look for evidence of ischemia (diminished pulses, poor capillary refill, anesthesia); loss of vibratory sense is an early sign. If available, a Doppler ultrasound device is useful to assess distal blood flow. Because edema continues to develop during the first 6–8 hours after burn injury of the extremities, frequent reevaluation is important.

Treatment

Patients with deep circumferential burns of the neck are candidates for early endotracheal intubation. Elevate the injured limb(s) of patients with circumferential wounds of the extremities in order to minimize development of edema. Remove rings or other jewelry that could act as a tourniquet when edema develops. If evidence of distal ischemia develops, escharotomy is indicated. Ideally this should be performed in a burn center by a surgeon experienced in this procedure. Occasionally escharotomy must be performed in the emergency department before the patient is transported to a burn center for definitive care. Sterilize the overlying skin and make medial and lateral incisions through the eschar using a No. 20 scalpel or electrocautery. Incise deeply enough to cut entirely through the burned skin and release the constricting eschar, being careful to avoid neurovascular structures (typically this occurs at the level of the subcutaneous fat). No anesthesia should be required as full-thickness burns are insensate. Blood loss is seldom significant but can be controlled by cautery or suture if necessary.

Patients with a circumferential chest wall burn may require escharotomy in the emergency department. Using sterile technique, incise the eschar along the anterior axillary line bilaterally to the costal margins, and then join these incisions with incisions along the costal margins and just below the clavicles. This releases a segment of chest wall eschar that can move with respiratory excursion.

Disposition

All patients with deep circumferential burns of the neck, extremities, or chest wall should be hospitalized, preferably in a burn center.

Burns Due to Child Abuse

Essentials of Diagnosis

• High index of suspicion
• Discrepancy between the history and physical findings

General Considerations

Burns represent 8–14% of child abuse injuries seen in the United States; about 15% of abused children have been intentionally burned at some time.

Clinical Findings

Suspect child abuse if there is a delay in seeking medical care, if there is a history of other injuries, or if there is a discrepancy between the history and the physical findings. The injuries most commonly encountered in the emergency department are burns of the buttocks and perineum caused by scalding immersion in hot water in children who are being toilet-trained and cigarette burns in children of any age.

Treatment and Disposition

The treatment of burns in children is the same as that of a burn of comparable size in any other patient, but if there is any suspicion that the injury was due to abuse, the child must be hospitalized and the attending physician informed of the emergency physician's suspicions. By law, suspected child abuse must be reported to the appropriate child welfare authorities. Obtain consultation with appropriate personnel as soon as possible (eg, social worker, nurse, psychologist, pediatrician).