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  3. Fagan SP, Bilodeau ML, Goverman J. Burn intensive care. Surg Clin North Am. 2014 Aug;94(4):765-79.
  4. Schiestl C, Meuli M, Trop M, Neuhaus K. Management of burn wounds. Eur J Pediatr Surg. 2013 Oct;23(5):341-8.
  5. Schwartz LR, Balakrishnan C. Thermal burns. In: Tintinalli JE, Stapczynski JS, Ma OJ, Cline DM, Cydulka RK, Meckler GM, eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York: McGraw-Hill; 2010.

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Contributor Information


Joseph U Becker, MD
Assistant Professor, Department of Emergency Medicine
Stanford University School of Medicine

Disclosure: Joseph U Becker, MD, has disclosed no relevant financial relationships.


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Thermal Injuries: A Matter of Degree

Joseph U Becker, MD  |  July 22, 2015

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Slide 1

Burns are a serious cause of human suffering and mortality globally. As many as 5% of burn victims will die as a result of their injuries, and many others will suffer disability, disfigurement, or scarring. Thermal injuries can be divided into six different categories: chemical burns, electrical burns, fire-related burns, radiation burns, scalds (typically caused by steam or hot liquids), and contact burns. Contact burns and scalds are the most common types of burn in children and toddlers, whereas electrical and fire-related burns are more common in older adults.

The severity of a burn is related to the rate at which heat is transferred to the body tissue. This transfer rate, in turn, is affected by the heat capacity of the heat source, its temperature, and the duration of contact. The heat capacity of the tissue in contact, in conjunction with the transfer coefficient, also plays a role in determining burn severity.[1]

Image courtesy of Wikimedia Commons.

Slide 2

In burn patients, survival and morbidity are directly related to burn size and depth. Accordingly, quantification of the depth of a burn (shown) is a vital task to perform early in the clinical assessment of the burn patient.

Redness, tenderness, and pain are common in first-degree burns. These findings denote minor, superficial damage to the epidermis. There is no blistering, and sensation is not impaired. Because the skin barrier remains intact, there are typically very few metabolic changes, and infection risk is low. Healing occurs within several days, usually without scarring. Common examples of first-degree burns are minor contact burns and sunburns.[1,2]

Image courtesy of Wikimedia Commons.

Slide 3

Second-degree burns (shown) are partial-thickness injuries in which the thermal damage extends beyond the superficial epidermis but does not extend fully through the dermis. Thus, some of the skin barrier is preserved, and healing usually occurs without need for skin grafting. Second-degree burns come in two types, superficial and deep, depending on how far the thermal damage has penetrated through the dermis. Superficial second-degree burns involve only the epidermis and the superficial dermis, usually resulting in blistering; severe pain is common. Deep second-degree burns extend into the reticular dermis, a deeper layer; thus, healing may be delayed and scarring more common. Thicker blisters are common with deep second-degree burns, and the tissue is usually more pale, though sensation is still intact. Infection is more frequent as well.[1,2]

Image courtesy of Wikimedia Commons.

Slide 4

Third-degree burns (shown) involve thermal injury that penetrates through all skin layers (dermis as well as epidermis). The capillary blood supply is destroyed, and there is no further perfusion of the skin. The skin appears white, and sensation is no longer intact. Because tissue has been destroyed, healing will not occur without skin grafting.

Fourth-degree burns penetrate through the skin and subcutaneous tissues and into the underlying tissues (eg, bones, muscles, and tendons). These burns arise from prolonged contact with heat sources and commonly are caused by electricity, chemicals, or fire.[1-5]

Image courtesy of Wikimedia Commons.

Slide 5

A 22-year-old man is brought into the emergency department (ED) after a report of an explosion and a fire that occurred at the patient's house as he was repairing his car. Obvious burns are apparent on the patient's arms, chest, and face. He is coughing and reports a sore throat, but his main complaint is of pain in his extremities.

Which of the following statements about burn patients is true and relevant to this patient's care?

  1. Most burn patients have low fluid needs
  2. Patients with burns to the face may have airway deterioration as a consequence of swelling and inflammation caused by inhalation injury
  3. Explosions typically do not result in significant carbon monoxide (CO) toxicity
  4. Children are frequently victims of burns via flame- and explosion-type injuries

Image courtesy of Wikimedia Commons.

Slide 6

Answer: B. Patients with burns to the face may have airway deterioration as a consequence of swelling and inflammation caused by inhalation injury.

Explosions may cause inhalation injuries, in which patients inhale hot gases and vapors and may sustain burns to their oropharynx or nasopharynx. These injuries can lead to delayed loss of the airway and respiratory failure. Consequently, in any patient with suspected airway burns or inhalation injury, it is critically important to secure a viable airway early in the course of care, before the airway can deteriorate. After airway deterioration has begun, intervention may be considerably more difficult.

Image courtesy of Wikimedia Commons.

Slide 7

In addition to the depth (ie, degree) of the burn, the surface extent of the thermal injury (expressed as the percentage of total body surface area [TBSA] burned) is an important determinant of its severity. The percentage of TBSA that is burned (applicable only to second- and third-degree burns) is estimated according to the so-called rule of nines, by which the adult body is divided into sections that each represent roughly 9% (or a multiple of 9%) of TBSA (shown). The palm is roughly 1% of TBSA and can be used to determine burns that occupy portions of the above distributions. The relative sizes of these distributions are different in children, who have proportionally larger heads and smaller legs than adults do. Survival is inversely proportional, and disability directly proportional, to the percentage of TBSA burned.[1,5]

Image courtesy of Medscape.

Slide 8

The location of the burn is also critically important. Deep second- or third-degree burns involving joints, the hands (shown), the face, or the perineum can be particularly disfiguring and disabling. Patient age has a significant effect on the prognosis: Survival from burns is lowest at the extremes of age, with elderly individuals and young children (particularly infants) having a higher mortality. Comorbidities are also a key consideration, as well as associated injuries (eg, traumatic injuries or inhalation or blast injury).[1]

Image courtesy of Naiyyer |

Slide 9

The American Burn Association has developed a classification scheme whereby the important factors determining burn outcome are used to classify burn patients into the following categories[2]:

  • Major burns
  • Moderate burns
  • Minor burns (shown)

Image courtesy of National Institutes of Health (NIH).

Slide 10

Minor burns (shown) comprise the following:

  • Burns involving <15% of TBSA in adults or <10% of TBSA in children
  • Full-thickness burns involving <2% of TBSA and not involving sensitive body parts (eg, eyes, hands, feet, and perineum)

The risk of infection or metabolic complications is low with minor burns. Most such burns can be managed in the outpatient setting with close follow-up.

Image courtesy of Dj0038 |

Slide 11

Moderate burns (shown) comprise the following:

  • Partial-thickness burns involving 15-25% of TBSA in adults or 10-20% of TBSA in children or the elderly
  • Full-thickness (third-degree) burns involving 2-10% of TBSA and not involving sensitive body structures (eg, eyes, hands, feet, and perineum)

To be classified as having moderate burns, patients must not have a concomitant severe traumatic injury, a comorbid condition, or an inhalation injury. Hospitalization is required, though burn center care may not be necessary.

Image courtesy of Wikimedia Commons.

Slide 12

Major burns (shown) comprise the following:

  • Partial-thickness burns involving >25% of TBSA in adults or >20% of TBSA in children or adults older than 50 years
  • Third-degree burns involving >10% of TBSA
  • Burns involving the hands, face, eyes, feet, or perineum
  • Burns caused by caustic chemical agents or electrical injuries
  • Burns complicated by inhalation or trauma
  • Burns in patients with significant underlying comorbidities

Patients with major burns require treatment in a burn center.[1,3,4,5]

Image courtesy of Medscape.

Slide 13

A 4-year-old girl is brought into the ED after being rescued from a burning apartment building. She has second- and third-degree burns to her extremities. She is crying and in distress.

Which of the following laboratory values is it most important to obtain in the initial workup of this patient?

  1. Serum creatine kinase (CK) level
  2. Serum potassium level
  3. Serum calcium level
  4. Carboxyhemoglobin (COHb) level

Image courtesy of Wikimedia Commons.

Slide 14

Answer: D. Carboxyhemoglobin (COHb) level.

Although this child has severe thermal injuries, and such injuries often demand immediate attention, it is vital to consider the possibility of CO poisoning and to treat it promptly if it is present. CO poisoning is frequently seen in patients rescued from fires, particularly those occurring in closed spaces. Initial symptoms include headache, dizziness, and nausea; in more severe cases, significant mental status alteration or neurologic findings may be noted. Patients with severe injuries and burns, as well as young children, may be unwilling or unable to provide a history of these symptoms. Measurement of the COHb level is an important diagnostic test for detecting CO poisoning. Lactic acidosis should be assessed as well; this may reflect the presence of additional toxicity (eg, from cyanide, which is a product of combustion of synthetic fabrics).

Image courtesy of Wikimedia Commons.

Slide 15

Prehospital care of patients who have sustained burn injury should be devoted to (1) reducing continuing exposure to the thermal agent and (2) providing initial resuscitation. Patients with significant burns may have sustained substantial fluid losses and may be hypothermic as a result of loss of heat energy through the damaged tissues. Close monitoring of temperature and provision of warmed fluids and heated blankets may be necessary. Patients with major burns, complicated injuries, or comorbid medical conditions should be transported directly to a specialized burn center if one is available no more than 30 minutes away.[1,3,4]

Image courtesy of Wikimedia Commons.

Slide 16

A tanker car explosion on the freeway produces several casualties. Which of the following is an important initial step when these patients are received into the ED?

  1. Make sure that the patient has adequate nutrition
  2. Immediately remove any remaining heat source or irritant that could further worsen the burn
  3. Prepare for early wound closure and skin grafting
  4. Institute early occupational and physical therapy to reduce the chances of disabling injury

Image courtesy of Adnan Islam | Wikimedia Commons.

Slide 17

Answer: B. Immediately remove any remaining heat source or irritant that could further worsen the burn.

Patients who have sustained fuel- or chemical-related burns may still have caustic chemicals or fuels on their bodies or their clothes, even after transport to the ED. These agents pose a risk to the burn patients themselves (residual fuel adds a heat source that worsens the burns; a residual chemical agent exacerbates chemical burns), to the staff, and potentially to other patients as well. Accordingly, all patients with suspected fuel or chemical exposure should be decontaminated before entry into the ED. Other immediate concerns in severely burned patients include airway and respiratory protection, analgesia, fluid resuscitation, and temperature regulation.

Image courtesy of Wikimedia Commons.

Slide 18

Initial management should focus on (1) stabilizing the patient and (2) assessing the extent and severity of the burn injury. Inhalation of hot gases or a direct burn to the upper airway may result in edema (shown), which can lead to loss of airway patency and respiratory distress in a matter of hours. Patients may present with singed facial hairs and soot in the mouth, throat, and nostrils, as well as cough, hoarse voice, or both. In addition, inhalation and blast injury may directly damage the lungs and alveoli, resulting in pulmonary edema and respiratory compromise. It is recommended that preemptive intubation and airway support be instituted promptly, before the abrupt loss of the airway can develop.[1,3,5]

Image courtesy of Medscape.

Slide 19

CO has nearly 300 times greater affinity for hemoglobin than oxygen does. Thus, if CO is present in higher-than-normal levels, it can reduce the oxygen-carrying capacity of the blood, leading to acidosis. CO poisoning can give rise to severe neurologic deficits and disability. Patients with COHb levels higher than 10% should receive 100% oxygen. Patients with elevated COHb levels and a pH lower than 7.4 or the presence of any neuropsychiatric findings or a history of unconsciousness should be treated with hyperbaric oxygen (shown) to avoid the potential for permanent neurologic disability. Elevation of lactic acid levels should also prompt treatment for potential cyanide poisoning.[1,3,5]

Image courtesy of Medscape.

Slide 20

Patients with significant burns can have substantial fluid losses. Fluid resuscitation in these patients is guided by the Parkland formula (shown). This formula requires an accurate determination of both the patient's weight and the percentage of TBSA burned. Adequate fluid resuscitation is evidenced by a urine output of at least 1 mL/kg/hr in children and at least 0.3 mL/kg/hr in adults. Monitoring of fluid status via central venous pressure monitoring or pulmonary artery pressure monitoring may assist in determining appropriate resuscitation. Even when the Parkland formula is employed, adequate resuscitation is not guaranteed: Patients may still manifest both volume overload and oliguria. In addition, the Parkland formula may underestimate fluid losses in children. The fluid of choice in children is 5% dextrose lactated Ringer solution.[1,3,5]

Image courtesy of Sam Shlomo Spaeth / Medscape.

Slide 21

Supportive care of the burn patient includes the following:

  • Analgesics and pain control
  • Nutrition – Protein losses in the early course of burns are substantial, and early administration of albumin may be required, particularly with significant volumes of crystalloid; attention to the nutritional needs of the patient (including total parenteral nutrition [TPN] as indicated) is critical
  • Attention to renal function – Renal failure may develop as a consequence of either inadequate hydration or rhabdomyolysis
  • Avoidance of infection – This includes monitoring for the development of infection, provision of topical antibiotic creams, and appropriate use of IV antibiotics as necessary

Image courtesy of Wikimedia Commons.

Slide 22

Care of the burn wound itself is probably the most critical component of burn treatment. This includes the following:

  • Daily dressing changes (more frequent dressing changes may be required in the setting of infection)
  • Wound debridement with surfactant and saline solutions initially, followed by application of topical antimicrobial creams (poloxamer 188, bacitracin, silver sulfadiazine)

Patients with larger burns and those with significant medical problems are at risk for fungal infections, which increase the mortality significantly.

Image courtesy of Medscape.

Slide 23

Additional aspects of burn wound care include the following:

  • Full-thickness burns may result in severely contracted scars that limit movement and, in the case of the thorax, respiration; incisions and escharotomy are sometimes required to allow adequate ventilation or perfusion
  • In severe cases, surgical debridement and excision of devitalized tissue may be necessary
  • Temporary wound closures (shown) may be accomplished with cadaveric skin or synthetic graft products
  • In full-thickness burns, skin grafting is typically necessary to reestablish a surface barrier

Image courtesy of Medscape.

Slide 24

A patient from a structure fire is brought in with severe, deep circumferential burns covering most of his chest, back, and abdomen. He is intubated and placed on a ventilator and receives IV morphine and appropriate fluid resuscitation. After several hours, the respiratory therapist calls to notify you that the patient is becoming increasingly hard to ventilate. Airway pressures are increasing, and pulse oximetry values are decreasing.

Which of the following actions is most likely to be necessary?

  1. Provide nebulized albuterol into the endotracheal tube; the patient probably has bronchoconstriction related to smoke inhalation
  2. Examine the chest wall for restrictive eschar formation that might necessitate surgical escharotomy
  3. Address pneumothorax related to a blast injury
  4. Treat pulmonary edema resulting from excessive fluid administration

Image courtesy of Wikimedia Commons.

Slide 25

Answer: B. Examine the chest wall for restrictive eschar formation that might necessitate surgical escharotomy.

There are several possibilities in this case, and certainly one would want to consider the possibility of pneumothorax or pulmonary edema related either to excessive administration of fluid or to trauma or blast injury. However, patients with severe circumferential thoracic burns commonly develop restrictive eschars that do not allow the chest wall to expand normally in respiration. This may give rise to respiratory failure in a restrictive pattern.

Image courtesy of Medscape.

Slide 26

Key considerations in the care of patients with thermal injuries may be summarized as follows:

  • Burns are a significant source of morbidity and mortality, particularly in children
  • Initial efforts should be aimed at assessing the depth and extent of the burn
  • If inhalation injury is suspected, early preemptive intubation and airway support are indicated
  • When appropriate, assessment for the presence of CO or cyanide poisoning is indicated
  • Attention to infection risk, as well as fluid resuscitation, is critical
  • Child abuse accounts for a significant fraction of scald and immersion burns in children
  • Patients with major burn injuries should be transferred to a burn center for specialized care

Image courtesy of Wikimedia Commons.

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