There are an estimated 1.2 million burn injuries per year in the United States. Of these, 50,000 patients are hospitalized and 4500 fire-related deaths occur. According to the 2012 Burn Repository Data, encompassing cases from 2002 to 2011, approximately 70% of patients who required admission were men with a mean age of 32 years. Children under 5 represented 19% of cases while patients older than 60 accounted for 12% of admissions. The overall mortality rate was 3.7%.¹

Risk factors for mortality from burn include age greater than 60, burn greater than 40% BSA, and the presence of inhalation injury. Mortality was 0% with zero risk factors, 3% with one risk factor, 33% with two risk factors, and 90% with all three risk factors.² A variety of types of injury can result in a burn, requiring some variation in management strategies.

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  List types and causes of thermal, chemical, and electrical injuries.

  
  
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  Describe the initial prehospital evaluation and management of thermal injuries.

  
  
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  Describe the initial prehospital evaluation and management of exposure to acids and bases.

  
  
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  Describe the initial prehospital evaluation and management of electrical injuries.

  
  
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  Describe the initial prehospital evaluation and management of blast injuries.

DEPTH OF INJURY

The depth of injury is generally a function of pressure, temperature, and time of exposure. Contact burns can occur from contact with an extremely hot surface, usually for a brief period of time. These are most often occupational injuries. However, prolonged exposure to lower temperature objects can also cause deep tissue burns and generally occur in elderly patients or those with epilepsy.³ First-degree burns are limited to the epidermis and cause erythema and pain similar to sunburn. Blisters do not form. Second-degree burns, also known as partial-thickness burns, involve epidermis and dermis. Blisters form early and if the area is denuded, the underlying dermis will be red and moist due to enhanced blood flow to this layer. The dermis will also retain its elasticity. Since nerve tissue remains viable, pain and proprioception remain intact. Third-degree burns, also known as full-thickness burns, involve all skin layers. The dermis will become charred and tough with the texture of leather. Sensation will be absent since the nerves are burned and the skin loses elasticity. Fourth-degree burns involve all skin layers and muscle or bone (Figure 58-1). These are usually seen in patients who were trapped or unconscious at the time of injury.

EVALUATION OF THE BURNED PATIENT

Of particular importance to EMS physicians who respond to the scene is scene safety. The responding physician must take care not to become a patient him or herself in the process of attempting to rescue the patient. Although the appearance and odor of the patient’s wounds can easily become the focus of attention, the EMS physician must initially “ignore” the burn and treat any associated trauma in accordance with Advanced Trauma and Life Support (ATLS) guidelines of the American Academy of Surgeons. Airway management, breathing, circulation, and environmental exposure must be initially addressed, followed by a complete history and physical examination. Estimation of burn surface area can be accomplished by using the “rule of 9s” (Figure 58-2) or the more accurate Lund and Browder chart ⁴ (Figure 58-3). An alternate method involves equating the patient’s palmar surface area to 0.5% of the total BSA.

Once the initial primary and secondary surveys have been completed, attention should be turned toward stopping the burning process. In some cases, the patient’s skin may still be smoldering and contaminated by products of combustion. Flooding quantities of water and a mild soap can be used. Appropriate analgesia must be provided during this process. Wounds should be covered with a clean dressing and, if available, a mild topical antibacterial agent. Silver sulfadiazine is a popular antibacterial agent, but bacitracin, polymyxin B, and neomycin may also be used. Broken bullae may be debrided or left intact. In cases where patients will be transported to a burn center, it may be more appropriate to avoid covering the burns in ointments that may need to be removed in order to allow for a burn surgeon to perform their evaluation.

Additionally, inhalation injury is present more frequently in patients with a serum carboxyhemoglobin greater than 10%, although a normal level does not exclude inhalation injury. Care must be taken to assess and reassess for signs and symptoms of inhalation injury. ⁵ Seventy percent of burn deaths are due to inhalation injuries.⁶ (Box 58-1)

Inhalation burns can be characterized by their location above or below the glottis and by the presence of concomitant carbon monoxide (CO) poisoning and/or cyanide poisoning.^7–10 Injury above the glottis is associated with upper airway edema. Because the oropharynx is very efficient at removing heat from air, inhaled gases will be at almost normal temperature when entering the lungs. The oropharynx will be erythematous and soot may be present. Hoarseness should be taken as a sign of potential laryngeal edema and the larynx should be evaluated. Tissue edema frequently progresses during resuscitation and laryngeal obstruction can occur. Intubation for airway protection should occur early rather than later if laryngeal edema is suspected. Many patients will have normal respiratory parameters for the first 24 to 48 hours following their injury so decisions regarding airway protection should be made after a careful history and physical examination, combined with EMS physician’s clinical suspicion.¹¹

Subglottic inhalation injury occurs when noxious smoke particles are inhaled into the lungs. This results in mucosal edema, loss of ciliary function, bronchorrhea, vasoconstriction, and bronchospasm. Bronchial casts (analogous to skin eschar) may form, causing airway obstruction. Actual thermal damage can occur if hot liquid aspiration occurs or in cases of explosions where hot air is forced into the lungs. Steam inhalation may be particularly damaging as the high moisture content of the air provides a much greater heat-carrying capacity. Although relatively rare, steam-related inhalational injury often progresses to respiratory failure within a few hours and is a poor prognostic factor.

Treatment of inhalation injury includes fluid resuscitation, airway protection, pulmonary toileting, bronchodilation, and mechanical ventilation if needed. Fluid requirements in patients with inhalation injury may be increased by 25% due to pulmonary edema. Routine intubation should be avoided, but progressive airway signs and symptoms should prompt consideration for early intubation. Mechanical ventilation parameters should be set in accordance with lung-protective ventilation strategies using a tidal volume of 6mL/kg (ideal body weight), high PEEP, and permissive hypercapnea.¹² Bronchodilators can be used to treat airway hypersensitivity and may improve pulmonary edema. Many burn centers use nebulized heparin and mucolytics to prevent the formation of airway casts. Prophylactic steroids and antibiotics are not indicated.

Smoke generally contains 10% to 20% CO but because smoke exposure is relatively short, an individual’s level may not be significant. Levels of 15% are often associated with neurologic impairment and levels higher than 60% may be fatal. The half-life of CO is 250 minutes at room air (FiO₂ = 0.21) but can be reduced to as low as 40 minutes with 100% oxygen. Individuals with smoke inhalation should be treated empirically with high flow oxygen prior to measurement of carboxyhemoglobin levels. Some EMS physicians may choose to use noninvasive carboxyhemoglobin monitors to guide therapy or transport destination, but at least one study has questioned the reliability of these devices.¹³

The presence of CO poisoning should lead the EMS physician to suspect associated cyanide toxicity. Cyanide is produced during the combustion of synthetic materials such as furniture foam and plastics. Because its half-life is short, treatment is rarely needed, but warranted if the patient remains persistently acidotic despite adequate resuscitation. Sodium thiosulfate and hydroxycobalamin are safe and effective treatments.

FLUID RESUSCITATION

Various resuscitation regimens have been devised and their use has dramatically reduced burn-related mortality.³ Underresuscitation may result in the progression of partial-thickness burns to full-thickness burns and the development of multiorgan system failure. Conversely, overly aggressive fluid resuscitation may increase tissue and pulmonary edema, leading to respiratory compromise. The Parkland formula can be used to estimate the amount of crystalloid fluid required within the first 24 hours.^14,15

One-half of the calculated volume is given over the first 8 hours (from the time of injury, not from the time of resuscitation initiation) and the remaining half is given over the next 16 hours. % BSA includes only second-degree or higher burns. It is important to remember that this is only an estimate and fluid resuscitation should be individualized to maintain a urine output of 0.5 to 1mL/kg/h. Fluid requirements may be increased if there is concomitant inhalation injury or electrical burn.⁶ Ringer lactate is used most commonly, but 0.9% normal saline is equally acceptable, especially in the prehospital setting.