Burns

Question 1

A 22-year-old man is brought to the emergency room after a house fire. He has burns around his mouth and his voice is hoarse, but breathing is unlabored. What most appropriate next step in management?

A. Immediate endotracheal intubation.

B. Examination of oral cavity and pharynx, with fiberoptic laryngoscope if available.

C. Place on supplemental oxygen.

D. Placement of two large-bore intravenous (IV) catheters with fluid resuscitation.

Answer 1

Answer: B

With direct thermal injury to the upper airway or smoke inhalation, rapid and severe airway edema is a potentially lethal threat.

Anticipating the need for intubation and establishing an early airway is critical.

Perioral burns and singed nasal hair are signs that the oral cavity and pharynx should be further evaluated for mucosal injury, but these physical findings alone do not indicate an upper airway injury.

Signs of impending respiratory compromise may include a hoarse voice, wheezing, or stridor; subjective dyspnea is a particularly concerning symptom, and should trigger prompt elective endotracheal intubation.

In patients with combined multiple trauma, especially oral trauma, nasotracheal intubation may be useful but should be avoided if oral intubation is safe and easy. (See Schwartz 10th ed., p. 227.)

Question 2

What percentage burn does a patient have who has suffered burns to one leg (circumferential), one arm (circumferential), and the anterior trunk?

A. 18%

B. 27%

C. 36%

D. 45%

Answer 2

Answer: D

A general idea of the burn size can be made by using the rule of nines.

Each upper extremity accounts for 9% of the total body surface area (TBSA), each lower extremity accounts for 18%, the anterior and posterior trunk each accounts for 18%, the head and neck account for 9%, and the perineum accounts for 1%.

Although the rule of nines is reasonably accurate for adults, a number of more precise charts have been developed that are particularly helpful in assessing pediatric burns.

Most emergency rooms have such a chart. A diagram of the burn
can be drawn on the chart, and more precise calculations of the burn size made from the accompanying TBSA estimates given.

Children younger than 4 years have much larger heads and smaller thighs in proportion to total body size than do adults.

In infants the head accounts for nearly 20% of the TBSA; a child’s body proportions do not fully reach adult percentages until adolescence.

Even when using precise diagrams, interobserver variation may vary by as much as ±20%.

An observer experience with burned patients, rather than educational level, appears to be the best predictor of the accuracy of burn
size estimation.

For smaller burns, an accurate assessment of
size can be made by using the patient’s palmar hand surface, including the digits, which amounts for approximately 1% of TBSA. (See Schwartz 10th cd., p. 229.)

Question 3

A 40-year-old woman is admitted to the burn unit after an industrial fire at a plastics manufacturing plant with burns to the face and arms. Her electrocardiogram (ECG) shows S-T elevation, and initial chemistry panel and arterial blood gas reveal an anion gap metabolic acidosis with normal arterial carboxyhemoglobin. What is the most appropriate next step?

A. Correction of acidosis by adding sodium bicarbonate to IV fluids.

B. Administration of 100% oxygen and hydroxocobalamin.

C. Transthoracic echocardiogram.

D. Blood culture with IV antibiotics.

Answer 3

Answer: B

Hydrogen cyanide toxicity may also be a component of smoke inhalation injury.

Afflicted patients may have a persistent lactic acidosis or S-T elevation on ECG.

Cyanide inhibits cytochrome oxidase, which is required for oxidative phosphorylation.

Treatment consists of sodium thiosulfate, hydroxocobalamin, and 100% oxygen.

Sodium thiosulfate works by transforming cyanide into a nontoxic thiocyanate derivative, but it works slowly and is not effective for acute therapy.

Hydroxocobalamin quickly complexes with cyanide and is excreted by the kidney, and is recommended for immediate therapy.

In the majority of patients, the lactic acidosis will resolve with ventilation and sodium thiosulfate treatment becomes unnecessary.

(See Schwartz 10th cd., p. 228.)

Question 4

Which of the following is a common sequelae of electrical injury?

A. Cardiac arrhythmias

B. Paralysis

C. Brain damage

D. Cataracts

Answer 4

Answer: D

Myoglobinuria frequently accompanies electrical burns, but the clinical significance appears to be trivial.

Disruption of muscle cells releases cellular debris and myoglobin into the circulation to be filtered by the kidney.

If this condition is untreated, the consequence can be irreversible renal failure.

However, modern burn resuscitation protocols alone appear to be sufficient treatment for myoglobinuria.

Cardiac damage, such as myocardial contusion or infarction, may be present.

More likely, the conduction system may be deranged.

Household current at 110 V either does no damage or induces ventricular fibrillation.

If there are no electrocardiographic rhythm abnormalities present upon initial emergency department evaluation, the likelihood that they will appear later is minuscule.

Even with high-voltage injuries, a normal cardiac rhythm on admission generally means that subsequent dysrhythmia is unlikely.

Studies confirm that commonly measured cardiac enzymes bear little correlation to cardiac dysfunction, and elevated enzymes may be from
skeletal muscle damage.

Mandatory ECG monitoring and cardiac enzyme analysis in an ICU setting for 24 hours following
injury is unnecessary in patients with electrical burns, even those resulting from high-voltage current, in patients who have stable cardiac rhythms on admission.

The nervous system is exquisitely sensitive to electricity.

The most devastating injury with frequent brain damage occurs when current passes through the head, but spinal cord damage is possible whenever current has passed from one side
of the body to the other.

Schwann cells are quite susceptible, and delayed transverse myelitis can occur days or weeks after
injury.

Conduction initially remains normal through existing myelin, but as myelin wears out, it is not replaced and conduction ceases.

Anterior spinal artery syndrome from vascular dysrégulation can also precipitate spinal cord dysfunction.

Damage to peripheral nerves is common and may cause permanent functional impairment.

Every patient with an electrical injury must have a thorough neurologic examination as part of the initial assessment.

Persistent neurologic symptoms may lead to chronic pain syndromes, and posttraumatic stress
disorders are apparently more common after electrical burns than thermal burns.

Cataracts are a well-recognized sequela of high-voltage electrical burns.

They occur in 5 to 7% of patients, frequently are bilateral, occur even in the absence of contact points on the head, and typically manifest within 1 to 2 years of injury.

Electrically injured patients should undergo a thorough ophthalmologic examination early during their acute care.

(See Schwartz 10th ed., p. 229.)

Question 5

An 8-year-old boy is brought to the emergency room after accidentally touching a hot iron with his forearm. On examination, the burned area has weeping blisters and is very tender to the touch. What is the burn depth?

A. First degree

B. Second degree

C. Third degree

D. Fourth degree

Answer 5

Answer: B

Burn wounds are commonly classified as superficial (first degree), partial thickness (second degree), full thickness (third degree), and fourth degree burns, which affect underlying soft tissue.

Partial thickness bums are classified as either superficial or deep partial thickness bums by depth of involved dermis.

Clinically, first-degree bums are painful but do not blister, second-degree burn have dermal involvement and are extremely painful with weeping and blisters, and third-degree burns are leathery, painless, and nonblanching.

(See Schwartz 10th ed., p. 229.)

Question 6

Three hours after a burn injury that consisted of circumferential, third-degree burns at the wrist and elbow of the right arm, a patient loses sensation to light touch in his fingers. Motor function of his digits, however, remains intact. The most appropriate treatment for this patient now would consist of

A. Elevation of the extremity, Doppler ultrasonography every 4 hours, and if distal pulses are absent 8 hours later, immediate escharotomy.

B. Palpation for distal pulses and immediate escharotomy if pulses are absent.

C. Doppler ultrasonography for assessment of peripheral flow and immediate escharotomy if flow is decreased.

D. Immediate escharotomy under general anesthesia from above the elbow to below the wrist on both medial and lateral aspects of the arm.

Answer 6

Answer: C

Third-degree burn injuries are characterized by almost complete loss of elasticity of the skin.

Thus, as soft tissue swelling progresses, neurovascular compromise may occur.

Failure to recognize this problem may result in the loss of distal extremities.

The most reliable signs of decreased peripheral blood flow in burned patients are slow capillary refill as observed in the nail beds, the onset of neurologic deficits, and decreased or absent Doppler ultrasonic pulse detection.

When vascular impairment is diagnosed, immediate escharotomics are indicated.

Anesthesia is not required for escharotomy—the burn area is insensate because skin nerve endings arc destroyed by third-degree burns. (See Schwartz 10th cd., p. 234.)

Question 7

What is the fluid requirement of a 50-kg man with first-degree burns to his left arm and leg, circumferential second-degree burn to his right arm, and third-degree burns to his torso and right leg.

What is the rate of initial fluid resuscitation?

A. 4.5 L over 8 hours, followed by 4.5 L over 16 hours

B. 4.5 L over 8 hours, followed by 6 L over 16 hours

C. 6 L over 8 hours, followed by 6 L over 16 hours

D. 6 L over 8 hours, followed by 9 L over 16 hours

Answer 7

Answer: A

The most commonly used formula, the Parkland or Baxter formula, consists of 3 to 4 mI/kg/% burn of lactated Ringer solution, of which half is given during the first 8 hours postburn, and the remain ing half over the subsequent 16 hours.

The concept behind continuous fluid requirements is simple.

The burn (and/or inhalation injury) drives an inflammatory response that leads to capillary leak; as plasma leaks into the extravascular space, crystalloid administration maintains the intravascular volume.

Therefore, if a patient receives a large fluid bolus in a prehospital setting or emergency department that fluid has
likely leaked into the interstitium and the patient still requires
ongoing burn resuscitation according to the estimates.

Continuation of fluid volumes should depend on the time since
injury, urine output, and mean arterial pressure.

As the leak clones, the patient will require less volume to maintain these
two resuscitation end points.

(See Schwartz 10th cd., p. 230.)

Question 8

A patient with a 90% burn encompassing the entire torso develops an increasing PCO, and peak inspiratory pressure.

Which of the following is most likely to resolve this
problem?

A. Increase the delivered tidal volume.

B. Increase the respiratory rate.

C. Increase the Fio2.

D. Perform a thoracic escharotomy.

Answer 8

Answer: D

The adequacy of respiration must be monitored continuously throughout the resuscitation period.

Early respiratory distress may be due to the compromise of ventilation caused by chest wall inelasticity related to a deep circumferential burn wound of the thorax.

Pressures required for ventilation increase and
arterial PCO2 rises.

Inhalation injury, pneumothorax, or other causes can also result in respiratory distress and should be appropriately treated.

Thoracic escharotomy is seldom required, even with a circumferential chest wall burn. When required, escharotomies are performed bilaterally in the anterior axillary lines.

If there is significant extension of the burn onto the adjacent abdominal wall, the escharotomy incisions should be extended to this area by a transverse incision along the costal margins.

(See Schwartz 10th ed., p. 230.)

Question 9

Which of the following is FALSE regarding silver
sulfadiazine?

A. Used as prophylaxis against burn wound infections with a wide range of antimicrobial activity.

B. Safe to use on full and partial thickness burn wounds, as well as skin grafts.

C. Has limited systemic absorption.

D. May inhibit epithelial migration in partial thickness wound healing.

Answer 9

Answer: B

Silver sulfadiazine is one of the most widely used in clinical practice.

Silver sulfadiazine has a wide range of antimicrobial activity, primarily as prophylaxis against burn wound infections rather than treatment of existing infections.

It has the added benefits of being inexpensive and easily applied, and has soothing qualities.

It is not significantly absorbed systemically and thus has minimal metabolic derangements.

Silver sulfadiazine has a reputation for causing neutropenia, but this association is more likely due to neutrophil margination from the inflammatory response.

True allergic reactions to the sulfa component of silver sulfadiazine are rare, and at-risk patients
can have a small test patch applied to identify a burning sensation or rash.

Silver sulfadiazine destroys skin grafts and is
contraindicated on burns or donor sites in proximity to newly grafted areas.

Also, silver sulfadiazine may retard epithelial
migration in healing partial thickness wounds.

Question 10

Successful antibiotic penetration of a burn eschar can be achieved with

A. Mafenide acetate

B. Neomycin

C. Silver nitrate

D. Silver sulfadiazine

Answer 10

Answer: A

Mafenide acetate is the antibiotic agent that penetrates burn eschar to reach the interface with the patient’s viable tissue.

This agent has the disadvantages that it is quite painful on any partial thickness areas, and it is a carbonic anhydrase inhibitor that interferes with renal buffering mechanisms.

Chloride is retained, and metabolic acidosis results. For these reasons, silver sulfadiazine is more commonly used in burn centers unless a major problem with burn wound sepsis is present.

(See Schwartz 10th ed., p. 232.)

Question 11

Which of the following is true regarding nutritional needs of burn patients?

A. The hypermetabolic response to burn wounds typically raises the basic metabolic rate by 120%.

B. Oxandrolone, an anabolic steroid, can improve lean body mass but can be associated with hyperglycemia and clinically significant rise in hepatic transaminitis.

C. Early enteral feeding is safe when burns are less than 20% TBSA, otherwise enteral feeding should await return of bowel function to avoid feeding a patient with gastric ileus.

D. For patients with greater than 40% TBSA, caloric needs are estimated to be 25 kcal/kg/day plus 40 kcal/%TBSA/day.

Answer 11

Answer: D

The hypermetabolic response in burn injury may raise baseline metabolic rates by as much as 200%. This can lead to catabolism of muscle proteins and decreased lean body mass that may delay functional recovery.

Early enteral feeding for patients with burns larger than 20% TBSA is safe, and may reduce loss of lean body mass, slow the hypermetabolic response, and result in more efficient protein metabolism.

Calculating the appropriate caloric needs of the burn patient can be challenging. A commonly used formula in nonburned patients is the Harris-Benedict equation, which calculates caloric needs using factors such as gender, age, height, and weight.

This formula uses an activity factor for specific injuries, and for burns, the basal energy expenditure is multiplied by two.

The Harris-Benedict equation may be inaccurate in burns of less than 40% TBSA, and in these patients the Curreri formula may be more appropriate.

This formula estimates caloric needs to be 25 kcal/kg/day plus 40 kcal/%TBSA/day.

The anabolic steroid oxandrolone has been extensively studied in pediatric patients as well, and has demonstrated improvements in lean body mass and bone density in severely burned children.

The weight gain and functional improvements seen with oxandrolone may persist even after stopping administration of the drug.

A recent double-blinded, randomized study of oxandrolone showed decreased length of stay, improved hepatic protein synthesis, and no adverse effects on the endocrine function, though the authors noted a rise in transaminases with unclear clinical significance.

(See Schwartz 10th cd., p. 232.)

Question 12

A 14-year-old girl sustains a steam burn measuring 6 by 7 inches over the ulnar aspect of her right forearm. Blisters develop over the entire area of the burn wound, and by the time the patient is seen 6 hours after the injury, some of the blisters have ruptured spontaneously. All of the following therapeutic regimens might be considered appropriate for this patient EXCEPT

A. Application of silver sulfadiazine cream (Silvadene) and daily washes, but no dressing.

B. Application of mafenide acetate cream (Sulfamylon), but no daily washes or dressing.

C. Homograft application without sutures to secure it in place, but no daily washes or dressing.

D. Heterograft (pigskin) duplication with sutures to secure it in place and daily washes, but no dressing.

Answer 12

Answer: D

A number of different acceptable regimens exist for treating small, superficial second-degree burn injuries. In all cases, the necrotic epithelium is first debrided.

Topical antibacterial agents then may be applied and the wounds treated open or closed with dressings changed daily or every other day.

Biologic dressings (homografts or heterografts) may be applied to superficial second-degree burns at the time of initial debridement. Typically, these dressings quickly adhere to the wounds, relieve pain, and promote rapid epithelialization.

These dressings should not be sutured in place, however, because suturing creates the potential for a closed-space infection and for conversion of a second degree to a full-thickness injury.

If a biologic dressing does not adhere, it should be removed immediately, and the wound should then be treated with topical antibacterial agents.

(See Schwartz 10th cd., p. 234.)

Question 13

Which is FALSE concerning surgical treatment of burn wounds?

A. Tangential excision consists of tangential slices of burn tissue until bleeding tissue is encountered. Thus, excision can be associated with potentially significant blood loss.

B. Human cadaveric allograft is a permanent alternative to split-thickness skin grafts when there are insufficient donor sites.

C. Bleeding from tangential excision can be helped with injection of epinephrine tumescence solution, pneumatic tourniquets, epinephrine soaked compresses, and fibrinogen and thrombin spray sealant.

D. Meshed split thickness skin grafts allow serosanguinous drainage to prevent graft loss and provide a greater area of wound coverage.

Answer 13

Answer: B

The strategy of early excision and grafting in burned patients revolutionized survival outcomes in burn care.

Excision is performed with repeated tangential slices using a Watson or Goulian blade until viable, diffusely bleeding tissue remains.

The downside of tangential excision is a high blood loss, though this may be ameliorated using techniques such as instillation of an epinephrine tumescence solution underneath the burn.

Pneumatic tourniquets are helpful in extremity burns, and compresses soaked in a dilute epinephrine solution are necessary adjuncts after excision.

A fibrinogen and thrombin spray sealant (Tisseel Fibrin Sealant; Baxter, Deerfield, IL) also has beneficial effects on both hemostasis and graft adherence to the wound bed.

Since full thickness burns are impractical for most burn wounds, split-thickness sheet autografts harvested with a power dermatome make the most durable wound coverings, and have a decent cosmetic appearance.

In larger burns, fleshed autografted skin provides a larger area of wound coverage. This also allows drainage of blood and serous fluid to prevent accumulation under the skin graft with subsequent graft loss.

Areas of cosmetic importance, such as the face, neck, and hands, should be grafted with nonmeshed sheet grafts to ensure optimal appearance and function.

Options for temporary wound coverage include human cadaveric allograft, which is incorporated into the wound but is rejected by the immune system and must be eventually replaced.

(See Schwartz 10th ed., p. 234.)

Question 14

A 45-year-old woman is admitted to a hospital because of a third-degree burn injury to 40% of her TBSA, and her wounds are treated with topical silver sulfadiazine cream (Silvadene). Three days after admission, a burn wound biopsy semiquantitative culture shows 10’ Pseudomonas
organisms per gram of tissue. The patient’s condition is stable at this time. The most appropriate management for this patient would be to

A. Repeat the biopsy and culture in 24 hours.

B. Start subeschar clysis with antibiotics.

C. Administer systemic antibiotics.

D. Surgically excise the burn wounds.

Answer 14

Answer: B

Bacterial proliferation in a burn wound may occur despite topical antibacterial agents. When bacterial proliferation has escaped control, as proved by quantitative burn wound biopsy, administration of antibiotics by needle clysis beneath the eschar is indicated.

This therapy is most effective if initiated early, before invasive burn wound sepsis has developed or wound colonization has reached greater than 10^4 organisms per gram of tissue.

Systemic antibiotics usually are ineffective at this point because by the third day after a burn, blood flow to a burn wound is markedly decreased. Thus, adequate levels of antibiotic are not achieved at the eschar-viable tissue interface where the bacterial proliferation is occurring.

Before the use of subeschar antibiotics, Pseudomonas sepsis of bum wounds accompanied by ecthyma gangrenosum was uniformly fatal in children.

Once colonization of a burn wound has occurred, surgical excision is extremely dangerous, as systemic seeding will occur.

(See Schwartz 10th ed., p. 232.)

Question 15

Fourteen days after admission to the hospital for a 30% partial thickness burn and hemodynamic instability requiring central venous access, a patient develops a spiking temperature curve. On physical examination, the central venous catheter insertion site was red, tender, and warm. The best treatment for this complication is to

A. Exchange of central venous catheter over guidewire, culture tip of previous catheter.

B. Treat patient with IV antibiotics until blood cultures drawn from catheter are negative.

C. Removal of central venous catheter, culture tip, and placement of new catheter on contralateral site.

D. Removal of catheter and treat patient with oral antibiotics and pain medication as needed.

Answer 15

Answer: C

Bum patients often require central venous access for fluid resuscitation and hemodynamic monitoring. Because of the anatomic relation of their burns to commonly used access sites, burn patients may be at higher risk for catheter-related bloodstream infections.

The 2009 CDC NHSN report (http://www.cdc.gov/nhsn/dataStat.html) indicates that American burn centers have higher infectious complication rates than any other ICUs. Because burn patients may commonly exhibit leukocytosis with a documented bloodstream infection, practice has been to rewire lines over a guidewire and to culture the catheter tip. However, this may increase the risk of catheter-related infections in burned patients and a new site should be used if at all possible.

(See Schwartz 10th ed.,p. 233.)

Question 16

A 24-year old male arrives at the emergency room with 2nd and 3rd degree burns to 50% TBSA. His weight is 70 kg. According to the Parkland formula how much fluid should you be administering in the first 8 hours:

a. NSS at 1,200 ml/hr
b. Ringer’s lactate at 1,200 ml/hr
c. Ringer’s lactate at 7,090 ml/hr
d. Ringer’s lactate at 875 ml/hr

Answer 16

d. Ringer’s lactate at 875 ml/hr

Question 17

Which type of burn would spontaneously re-epithelialize from retained epidermal structures in the rete ridges, hair follicles, and sweat glands in 7 to 14 days?

a. Superficial second degree
b. Deep second degree
c. Third degree
d. Fourth degree

Answer 17

a. Superficial second degree

Question 18

Which of the following is a determinant of a burn patient’s final appearance and functional outcome?

a. Burn size
b. Burn depth
c. Rapidity of resuscitation
d. Nature of burn

Answer 18

b. Burn depth

Question 19

What is the basic pathology contributing to shock in burn patients?

a. Shift of interstitial fluid to intravascular space
b. Increased microvascular permeability
c. Dehydration 2 to exposure to extreme heat
d. Increased insensate loss due to exposure of burned areas

Answer 19

b. Increased microvascular permeability

Question 20

Select the true statement regarding the epidemiology of burn injury:

A. Most burn injuries occur in occupational environments.

B. Young adult men are the most likely to suffer burn injury.

C. The most common cause of death after admission for a burn injury is airway occlusion.

D. Scalding is the most common cause of burns in children younger than 5 years.

E. Prevention has not had a significant impact on the incidence or mortality of burn injury.

Answer 20

ANSWER: D

COMMENTS: Approximately 1 million injuries are caused by thermal trauma yearly in the United States.

The majority of burn injuries occur in the home (43%).

In general, 65% of burns occur in non–work-related accidents, 17% in work-related accidents, and 5% each in recreational or in assault or abuse cases.

House fires contribute to 75%–80% of deaths from burns. Burns occur in a bimodal distribution, with an increased risk occurring in children younger than 4 years and adults 65 years and older.

African-Americans and Native Americans are disproportionately affected.

Burns occur more frequently in vulnerable populations, including those with epilepsy, those with heavy alcohol use, the poor, and people living in substandard housing.

Asphyxiation is a common cause of death at the scene of a fire, but the most common recorded cause of death in burn patients after admission is multi- organ failure.

Other causes, in decreasing order of frequency, are shock, trauma, pulmonary failure or sepsis, cardiovascular failure, and burn wound sepsis.

Hot-water scald injuries are the most common cause in children younger than 5 years, with flame burns becoming more frequent in those 5 years and older.

Ordinances requiring water heaters to be set at no higher than 120°F have decreased the incidence of scald burns.

Efforts at prevention have significantly decreased the number of burn injuries occurring in the United States, although disabled or impaired individuals are still at risk.

Question 21

Which of the following regarding burn wound depth is true?

A. First-degree burns heal rapidly but contribute significantly to the total body surface area (TBSA) burned in large, mixed-depth wounds.

B. Second-degree burns characteristically cause erythema, pain, and blistering.

C. Third-degree burns are generally painful and extremely sensitive to touch.

D. Fourth-degree burns mandate amputation of the involved extremities.

E. Superficial partial-thickness burn is the contemporary term for first-degree burns.

Answer 21

ANSWER: B

COMMENTS: The skin consists of two layers: epidermis and dermis. The epidermis is composed of five progressively differentiated layers of keratinocytes, the outermost of which, the stratum corneum, is relatively impermeable.

The epidermis provides barrier functions and protects against infection, absorption of toxins, exposure to ultraviolet light, and fluid and heat loss.

The dermis is a cellular and extracellular layer that provides the skin with durability and elasticity. Within the dermis, fibroblasts synthesize mesenchymal proteins, and inflammatory cells are present and contribute to the inflammatory responses to injury.

Dermal papillae interdigitate with the epidermal rete ridges to form the dermal–epidermal junction, a site affected by some exfoliative diseases of the skin.

Superficial, or first-degree, burns involve only the epidermis and are erythematous and painful.

The damaged epidermis will slough off within 3 to 4 days and be replaced by regenerating keratinocytes.

Most sunburns are first degree, and the treatment of superficial burns is similar to that of sunburns. Superficial burns do not contribute significantly to the systemic response to burn injury and are not counted in the percentage of TBSA (%TBSA) burned.

Partial- thickness burns (second degree) involve both the epidermis and dermis and are subdivided into superficial partial thickness and deep partial thickness, depending on the depth of dermal involve- ment.

Superficial partial-thickness burns involve the papillary dermis. Blistering occurs within 24 h of injury.

The exposed underlying dermis is typically pink, blanching, moist, and tender to touch because the nerve endings are preserved. These burns heal within 2 to 3 weeks with little risk of scarring.

Deep partial-thickness burns extend to the reticular dermis and may require more than 3 weeks to heal. These wounds blister and reveal mottled pink/white dermis. Sensation may be decreased, and the wounds may dry after initial observation. If deep partial-thickness wounds take longer than 3 weeks to heal, grafting may be required.

Full-thickness (third-degree) burns extend through the entire dermis into subcutaneous tissue. Full-thickness burns may be dry, leathery, firm, and insensate. Even if mottled in appearance, they do not blanch and may be hemorrhagic. These wounds require excision of the burn eschar and skin grafting for closure.

Indeterminate-depth wounds may be difficult to judge by initial appearance. Their potential to heal should be determined with serial observations because the initial evaluation may be inaccurate, even by experienced clinicians.

Light reflectance techniques, fluorescein, thermography, and magnetic resonance imaging have not proved useful with respect to serial clinical evaluation.

Noncontact laser Doppler imaging can be helpful but has not gained widespread clinical use.

Fourth- degree burns extend to muscle, bone, or other deep structures. They are particularly common with electrical injuries or burns with prolonged contact occurring in impaired patients. These very deep burns pose serious reconstructive challenges, and amputation may be required when the extremities or digits are involved.

Question 22

Which of the following statements regarding the order or description of the zones of injury is correct?

A. A zone of hyperemia inside a zone of stasis

B. A zone of hyperemia superficial to a zone of stasis, with a deeper zone of coagulation beneath

C. A zone of coagulation at the surface of a burn wound, a zone of stasis within the injured dermal layer, and a deep zone of hyperemia characterized by vasodilated subcutaneous vessels

D. A zone of coagulation, surrounded by a zone of stasis, which is surrounded by a zone of hyperemia

E. A zone of hemorrhagic burn that must be coagulated, a zone of stasis in which the depth of burn injury is already fixed, and a zone of hyperemia that may convert to coagulation

Answer 22

ANSWER: D

COMMENTS: Jackson’s classification of zones of injury in 1953 referred to the varying depth of injury radiating outward from a burn wound and defined the pathophysiology of cutaneous thermal injury.

The central zone of coagulation is necrotic and irreversibly damaged; it represents a full-thickness injury that will require excision and grafting.

The zone of stasis refers to the immediately surrounding region and is characterized by constricted vessels and hypoxia.

Initially viable, this tissue may convert to coagulation or a full-thickness injury as a result of edema, infection, or shock with decreased perfusion.

The zone of stasis may remain viable if adequately perfused.

In a patient with a large-TBSA burn, the viability of this zone may be critical in providing donor sites and reducing the total area that requires grafting.

The zone of hyperemia surrounding this is characterized by vasodilation as a result of inflammatory mediators and is viable.

Question 23

Select the most accurate statement regarding burn injury:

A. Contact burns occur commonly and rarely require grafting.

B. Intoxication is infrequently associated with deep burn injury.

C. Circumferential burns on both feet are seen in accidental bathing injuries in children.

D. Flash burns are generated by brief, intense heat, and articles of clothing are frequently protective.

E. Electrical burns are deeper than they appear because of the high flash temperatures generated by arcing.

Answer 23

ANSWER: D

COMMENTS: The mechanism of burn injury, if known, may aid in assessing the wound depth and predicting its capacity to heal. Flash burns are responsible for 50% of admissions to burn centers.

Explosions caused by natural gas, propane, and gasoline vapors generate brief, intense heat.

If not directly ignited, clothing is protective, with burns affecting only the exposed skin.

The depth of injury can be variable; many flash burns heal without grafting.

Flame burns generally result in a deep dermal or full-thickness injury because of the duration of exposure.

Structure fires and ignition of bedding or clothing are common causes of flame burns, and burn depth is proportional to the time required to remove the burning or smoldering material from the victim.

Intoxication or carbon monoxide (CO) poisoning occurring during a house fire increases the likelihood of deep flame burns.

Scald burns are the second most common cause of burns in the United States. The depth of injury is related to the water temperature and the duration of contact. At 140°F (60°C), water causes a deep dermal injury in 3s. Clothed areas may be scalded more deeply because of prolonged contact with the wet fabric before removal. Young children and elderly patients will scald faster and at lower temperatures. If not cautious, diabetic patients may accidentally scald themselves when soaking neuropathic or insensate feet in hot water. These burns are frequently deep partial to full thickness, and such patients are likely to have impaired healing as a result of their comorbid conditions. Hot oil and grease burns tend to be deep partial or full thickness because of the very high temperatures reached while cooking or heating oil.

Contact burns result from direct contact with a heat source and often occur in work environments. The hot presses used in industrial applications can cause particularly devastating combined crush/burn injuries that may result in poor functional outcomes.

Deep contact burns in domestic environments occur in children or impaired individuals (drugs, alcohol). Palmar or plantar surface burns generally deserve a period of observation because of the propensity of the thicker dermis of these surfaces to heal and less optimal results in terms of sensation and function obtained with split-thickness skin grafting in these areas.

Electrical injuries may cause deep tissue destruction that belies the surface wound when current flows through the patient, but flash burns from electrical arcing without direct contact are similar to flash burns from other sources.

Question 24

Which of the following patients do not meet the criteria for referral to a burn center?

A. A 50-year-old woman with a 1% TBSA partial-thickness burn on her left hand from a cooking accident

B. A 30-year-old construction worker with pain and blistering bilaterally on the knees after kneeling in wet cement all afternoon

C. A 25-year-old man with 7% TBSA partial-thickness burns on the chest

D. A 42-year-old woman with no cutaneous injury, found lying down at the scene of a house fire, and noted to have carbonaceous sputum after intubation in the field

E. An 18-year-old man in a motor vehicle collision with 30% TBSA burns on his chest and circumferential burns bilaterally on his arms

Answer 24

ANSWER: C

COMMENTS: The American Burn Association and the American College of Surgeons Committee on Trauma have published guidelines for patient referral to a burn center for care:

(1) partial- thickness burns on greater than 10% of TBSA;
(2) burns that involve the face, hands, feet, genitalia, perineum, or major joints;
(3) third-degree burns (any size) in any age group;
(4) electrical burns, including lightning injury;
(5) chemical burns;
(6) inhalation injury;
(7) burn injury in patients with preexisting medical disorders that could complicate management, prolong recovery, or affect mortality;
(8) any patient with burns and concomitant trauma (such as fractures) in which the burn injury poses the greatest risk for morbidity or mortality (in such cases, if the trauma poses a greater immediate risk, the patient’s condition may be stabilized initially in a trauma center before transfer to a burn center);
(9) burned children in hospitals without qualified personnel or equipment for the care of children; and
(10) burn injuries in patients who will require special social, emotional, or rehabilitative intervention.

These criteria are not meant to be exclusive, and many centers will treat patients with wounds smaller than those mentioned in the guidelines.

Many burn centers care for patients with exfoliative skin disorders, major wounds, necrotizing infections, and other diseases that require significant wound management and critical care.

Question 25

A 25-year-old patient has been in the burn intensive care unit (ICU) intubated and sedated for 2 weeks after an 80% TBSA burn. He suddenly develops hypotension, tachycardia, and melena. What type of surgical problem is this patient most likely to have?

A. Curling’s ulcer
B. Cushing’s ulcer
C. Marjolin’s ulcer
D. Dieulafoy’s lesion
E. Boerhaave’s syndrome

Answer 25

ANSWER: A

COMMENTS: Patients who are critically ill are at risk for a number of gastrointestinal emergencies as a result of their index injury.

A Curling’s ulcer is upper gastrointestinal bleeding in a burn patient, related to gastritis. Incidence is now decreased to 4% due to improved critical care, chemical ulcer prophylaxis, and early tube feeding.

A Cushing’s ulcer is similar, but presents in patients with severe neurologic injury and is likely related to increased intracranial pressure.

Management of both types of ulcers is similar, with the patient receiving aggressive resuscitation, correction of coagulopathies, proton pump inhibitor administration, and endoscopic coagulation or clipping of any visible sources of bleeding.

Selected arterial embolization can be used as an adjunct. Surgery is a last resort for patients who have persistent bleeding.

A Marjolin’s ulcer is the malignant transformation of a chronic wound (burn scars, hidradenitis suppurativa, venous stasis ulcers, fistula tracts, or any other chronic wound) into squamous cell carcinoma.

This type of squamous cell carcinoma is very aggressive and will need wide local excision and metastatic workup.

A Dieulafoy’s lesion is a vascular malformation of large vessels (1 to 3 mm), in the stomach, usually along the lesser curve submucosa, and can result in massive blood loss.

The mucosal defect overlying the vessel is often small, but the vessel itself is usually amenable to endoscopic clipping, which is successful >80% of the time.

Boerhaave’s syndrome is an esophageal perforation, usually distal, resulting from esophageal sphincter dysfunction caused by repeated vomiting.

Question 26

A 45-year-old patient presents after being burned in a house fire. The patient has deep, dry, and painless circumferential burns around both legs, the anterior torso and abdomen, and the circumferential left arm. Additionally, the patient has painful erythema involving the circumferential right arm. What is this patient’s %TBSA?

A. 63% 
B. 72% 
C. 45% 
D. 81% 
E. 36%

Answer 26

ANSWER: A

COMMENTS: The correct burn size estimation is crucial to burn care.

The percentage of the TBSA burned guides all aspects including need for transfer, fluid administration, and prognosis. Overestimation can have negative effects, primarily overresuscitation and resultant problems of respiratory failure and compartment syndromes.

Underresuscitation is also problematic as patients can progress into shock or renal failure.

There are many different methods used to calculate TBSA, but the easiest and the most rapid assessment tool is called the “rule of nines,” which divides the body into the following sections: head and neck, 9%; each upper extrem- ity (front and back), 9%; anterior trunk, 18%; posterior trunk, 18%; anterior lower extremity (each), 9%; posterior lower extremity (each), 9%; and perineum/genitalia, 1%. Only partial-thickness (second degree) or full-thickness (third degree) burns should be included in the TBSA calculation; any areas of superficial, or first- degree, burns are not included.

Another pitfall is using the adult “rule of nines” to calculate infant or pediatric TBSA. More detailed tools, such as the Lund-Browder chart, analyze the body surface area more accurately by smaller divisions and are adjusted for age (children have proportionally larger heads and smaller legs).

Alter-natively, small or scattered patches of burn can be estimated by using the surface of the patient’s palm to represent 1% TBSA.

Providers should also be cautioned that any scoring system is only an initial guideline for starting resuscitation and that fluid administration, hemodynamics, lab values, and urine output should be closely monitored to prevent over- or underresuscitation.

Question 27

A 22-year-old, 100-kg male presents with 70% TBSA burns. He initially presented directly from the scene to an outside hospital and has been getting a liter of normal saline an hour until he was able to be air-lifted to the burn center. In the 4 h since his burn, he has received 5 L of lactated Ringer’s solution. He is currently hypotensive and oliguric. Which initial fluid administration plan is best for continued resuscitation of this patient?

A. Continue bolusing 1 L of normal saline each time the patient is hypotensive

B. Lactated Ringer’s solution (LR) at 1125 mL/h for 8 h and then 875 mL/h for the following 16 h

C. Immediate transfusion of two units of packed red blood cells

D. LR at 2250 mL/h for 4 h and then 875 mL/h for the following 16 h

E. LR at 1750 mL/h for 8 h and then 875 mL/h for the following 16 h

Answer 27

ANSWER: D

COMMENTS: The Parkland formula (4 mL of lactated Ringer’s solution × TBSA × weight in kg) is most commonly used to estimate the fluid resuscitation requirements for the first 24 h after a burn injury.

This formula calls for 4 mL/kg per %TBSA burn to be given over a 24-h period. Half of the volume should be given over the first 8 h after injury and the remainder over the following 16 h.

A common error is not taking into account fluid already administered prior to arrival, which can lead to overestimation of the amount of fluid needed. Another error is calculating the start time of fluid administration from presentation to the hospital, instead of the time of injury.

For this patient, the initial calculation is 4 mL × 100 kg × 70 TBSA = 28,000 mL of lactated Ringer’s solution to be given in the first 24 h after injury.

Half (14,000 mL) should be given over the first 8 h, taking into account the 5000 mL administered prior to arrival for a remaining balance of 9000 mL to be given in the remaining 4 h (9000 mL/8 h = 2250 mL/h).

The remainder should be given over the following 16 h (14,000 mL/16 h = 875 mL/h).

Pediatric patients will need the normal weight- based rate of maintenance fluids with glucose due to their low glycogen stores and inability to concentrate urine.

It is important to remember that any formula used to guide resuscitation is only the best estimate of the patient’s needs.

Many factors, including the patient’s cardiovascular status, concomitant injuries from trauma, medical comorbidities, and age can all affect the response to volume administration.

The patient’s response to resuscitation should be monitored and IV fluids adjusted to the patient’s urine output.

The most useful marker of resuscitation is adequate hourly urine output, defined as 30 to 50 mL/h in adult patients and 1 mL/ kg/h in children in the absence of myoglobinuria.

Crystalloid boluses should be avoided unless required because of hypotensive episodes (mean arterial pressure persistently less than 60 mmHg) or to resuscitate blood loss from other traumatic injuries.

Intravenous fluids are rapidly extravasated as a result of the capillary leakage that occurs in the first 48 h.

Decreased urine output for 1 to 2 h would require increasing the hourly fluid rate.

Adequate or excessive urine output may prompt the reduction of fluid administration rates.

It is important to decrease fluid administration if not required because the morbidity (abdominal and extremity compartment syndromes, pulmonary edema) from massive volumes of resuscitation fluid is not insignificant.

Question 28

Which of the following is correct regarding inhalation injury in burn patients?

A. The admission chest radiograph is useful for ruling out inhalation injury on admission.

B. Supraglottic inhalation injury may necessitate intubation even if gas exchange is initially unaffected.

C. With proper pulmonary toilet, pneumonia is an unusual complication of smoke inhalation.

D. Smoke inhalation is basically just a subset of acute respiratory distress syndrome (ARDS) seen in burn victims.

E. Daily bronchoscopy is mandatory to monitor the evolution of inhalation injury.

Answer 28

ANSWER: B

COMMENTS: Inhalation injury occurs in up to a third of major burns and significantly increases mortality in patients when com- bined with cutaneous burns.

Conceptually, inhalation injury can be divided into three types, all of which can coexist within any given patient: CO poisoning (and other toxic inhalation), upper airway thermal injury, and lower airway injury.

Upper airway burns occur as a result of a thermal injury, as well as the toxic substances in smoke. The capacity for the oropharynx to absorb heat generally prevents the thermal injury from extending lower into the airway.

Oropharyngeal thermal injury can be diagnosed by direct laryngoscopy and, if significant, is an indication for prophylactic endotracheal intubation to control the airway before life-threatening airway edema develops, particularly after large-volume resuscitation ensues.

Endotracheal tubes may be difficult to secure if the patient has facial burns. They may be tied with cotton tape wrapped around the face.

Airway edema occurs a maximum of 12 to 24 h after injury, and if airway protection is required, the patient may remain intubated for 72 h. Short courses of steroids may be considered in patients without significant burns, but they are contraindicated in those with large burns because of infectious and wound complications.

Extubation may be performed when the patient has met weaning parameters and edema has subsided. Lower airway inhalation injury results from exposure of the respiratory epithelium to toxic irritants in smoke or steam.

Chest x-ray findings on admission are typically normal because infiltrates and lung injury tend to develop in delayed fashion over the days following injury.

Damage to the airway leads to inflammation, sloughing of mucosa, and impaired ciliary function, which results in edema, hemorrhage, bronchoconstriction, and bronchial obstruction.

Pulmonary edema, ARDS, and pneumonia may complicate inhalation injury, with pneumonia occurring in up to 50% of patients.

Lower airway inhalation injury is diagnosed most commonly by fiberoptic bronchoscopy, although nuclear medicine ventilation–perfusion scanning has been used.

Treatment is primarily supportive and consists of aggressive pulmonary toilet, supplemental oxygen, and endotracheal intubation if required for either airway protection or oxygenation.

Bronchoscopy may be used as an adjunct for pulmonary toilet if airway plugging leads to lobar collapse, but it is not always required for management.

Aerosolized heparin is administered by some centers to aid mobilization of fibrin-rich casts, which contribute to airway obstruction.

Laboratory and clinical research is ongoing for therapies dealing with smoke inhalation injury.

Patients with severe inhalation injury may be extremely difficult to ventilate, and ventilatory strategies vary among burn centers.

Low–tidal volume ventilation, high-frequency oscillatory ventilation, and even extracorporeal membrane oxygenation (ECMO) have been used by burn units.

Question 29

An 18-month-old boy presents to the burn unit after sustaining a scald burn to the buttocks. Which of the following burn patterns or components of the history is MOST suspicious for intentional burns in children?

A. Irregular burn margin and depth

B. Large TBSA of scald

C. Scald injury sustained from spilling of nonwater hot liquid

D. Symmetrical involvement of extremities

E. Trunk, neck, or head involvement

Answer 29

ANSWER: D

COMMENTS: Intentional burns comprise assault burns and self- inflicted burns. It is important for the provider to be cognizant of the risk factors for intentional burns and to identify injury patterns characteristic of this type of injury.

Vulnerable populations for intentional burns vary secondarily to geographic and cultural forces.

In the United States, vulnerable populations include those with mental illness or history of drug abuse, victims of domestic violence, the elderly, and most often, children.

Maguire et al. published a systematic review of 26 studies to identify the injury patterns of intentional burns in children that were most suspicious for intentional motives. They found 15 unique characteristics of intentional burns grouped into mechanism (immersion), agent (hot tap water), pattern (clear upper margins, symmetrical scalding), distribution (isolated scald on the lower extremities, buttock, or perineum), and additional clinical features (history discordant with physical examination, associated injuries including fractures, introverted child on physical examination, and previous episodes of abuse). With any of these characteristics, the provider should rule out intentional injury.

Additional potential abuse-related burn patterns include skin fold sparing, stocking and glove distribution, and uniform scald depth.

Characteristics not representative of intentional burns include spill/flowing water injury, scald from hot beverage, and irregular margin and depth.

However, it is important for the provider to take the entire history and physical examination into account as low-risk characteristics do not entirely rule out intentional injury.

No study has demonstrated large TBSA, child age, or gender as risk factors.

Question 30

A 45-year-old man presents following a motor vehicle crash with 30% TBSA burns to the torso, face, and extremities. On presentation to the trauma bay, he is alert with a Glasgow coma score (GCS) of 15, but is hypotensive with diffuse abdominal pain. Which of the following is true regarding the management of combined trauma and burn victims?

A. Chest tubes should be placed through burned skin as the chest tube dressing serves as appropriate additional coverage for the burn.

B. In a patient with thoracic trauma and concern for pulmonary contusions and chest wall burns, patients should be deliberately underresuscitated to prevent an increase in pulmonary edema.

C. In patients with abdominal trauma and abdominal burns, a paramedian incision is recommended due to its lower rates of dehiscence.

D. The most common cause of combined trauma and burn injuries is from house fires and falling debris.

E. A neurologically impaired patient following automobile accident and fire must be quickly assessed for CO and cyanide poisoning as this can exacerbate traumatic brain injury.

Answer 30

ANSWER: E

COMMENTS: The simultaneous trauma and burn patient poses additional diagnostic and management challenges to the health care provider. Roughly 5%–7% of burn admissions will have additional traumatic injuries.

In a large, 10-year retrospective study from Los Angeles County Burn Center, mortality for concomitant burn and trauma patients was 13% versus 6% of burns without additional trauma.

Patients with inhalation injury were the highest-risk subgroup with a mortality of 41%. The origin of injury is most commonly from motor vehicle crashes, followed by falls from height in house fires.

The management of the combined burn and trauma patient begins similar to that of the monotrauma patient with assessment of the patient’s airway, breathing, and circulation.

In combined burn and trauma patients, each of the three components of the primary survey has nuanced features that focus on the diagnosis of burn-specific injuries, or those anatomic structures at increased risk of injury from burns and traumatic injury.

For example, in the evaluation of the airway, the provider must assess for inhalation injury and progressive upper airway edema with careful attention to the cervical spine prior to manipulation of the neck during intubation or bronchoscopy.

During the assessment of the patient’s ability to breathe, victims of automobile or structural fires are at risk for CO or cyanide poisoning, both of which can cause hypoxia and further exacerbate an existing traumatic brain injury.

Treatment is 100% oxygen.

Poor respiratory function may be secondary to a number of causes including inhalation injury, thoracic trauma, or ARDS. Judicious fluid administration, not deliberate underresuscitation, is indicated.

A special subgroup of patients may require tube thoracostomy with overlying thoracic burns. These should be placed through healthy skin, if available, or otherwise through burn eschar.

Hypotension in the traumatically burned victim must be first ruled out as secondary to hemorrhage. Resuscitation begins with 2 L of crystalloid and assessment of the patient’s hemodynamic response, followed by adequate resuscitation by calculation of the patient’s 24-h volume requirements.

For those who require laparotomy with abdominal burns, a paramedian incision has been associated with higher rates of dehiscence.

Furthermore, special attention should be paid to the mode of abdominal wall closure in a burn patient who requires large-volume crystalloid resuscitation to prevent abdominal compartment syndrome.

Question 31

An 88-year-old woman suffers 11% TBSA superficial partial-thickness burn as a result of scalding with hot soup. Which of the following is most correct regarding the topical antimicrobial agents that may be used?

A. Mafenide acetate is an undesirable choice because of metabolic alkalosis caused by carbonic anhydrase inhibition.

B. Silver nitrate solutions can lead to methemoglobinemia, which causes a shift of the oxygen–hemoglobin dissociation curve to the right.

C. Silver sulfadiazine should be discontinued if neutropenia occurs as a result of its use.

D. Silver sulfadiazine induces epithelial cell migration, but it is often painful on application.

E. Elemental silver-impregnated dressings must be moistened frequently with sterile water to retain the antimicrobial activity.

Answer 31

ANSWER: E

COMMENTS: Systemic antibiotics are not indicated for prophylaxis.

Topical antimicrobial agents delay colonization and infection of wounds but have not changed mortality as much as early excision and grafting have.

Silver sulfadiazine is the most commonly used agent for burns in the United States. Advantages include a broad spectrum of activity, soothing effect in most patients, and no significant metabolic activity. Silver sulfadiazine does not penetrate eschar, so it does not treat established wound infections. Many providers have implicated it as a cause of early postburn neutropenia, but this neutropenia is typically self-limited, and more current information suggests that it is more likely the result of margination of neutrophils rather than depletion by the topical agent. One other caution is the use of silver sulfadiazine in a sulfa-allergic patient.

Mafenide acetate penetrates eschar and is therefore useful for the treatment of burn wound infections; it has a broad spectrum of activity against gram-negative organisms. It may be applied as a cream or a solution and is often used after grafting. Mafenide acetate is a carbonic anhydrase inhibitor that may cause metabolic acidosis when used on large areas. It is also painful on application, particularly to partial-thickness burns.

Silver nitrate has a broad spectrum of activity and may be used for burn wound dressings. Dressings need to be repeatedly impregnated with an aqueous solution to prevent precipitation onto the wound. Concentrated silver nitrate may cause chemical burns and hyponatremia, along with the rare case of methemoglobinemia. Wounds, normal skin, linens, and the patient environment will be stained black by silver nitrate.

Ointments of bacitracin, neomycin, and polymyxin B are commonly used for facial burns.

Mupirocin has been used against methicillin- resistant Staphylococcus aureus (MRSA).

Acticoat (Smith & Nephew, London, England) is a dressing impregnated with elemental silver that may be applied to burn wounds or grafts.

Sheets of Acticoat are usually moistened in sterile water before application because sodium chloride will cause precipitation and inactivation of the silver ions.

Silver disrupts bacterial cellular respiration, and silver dressings may be left in place for up to 7 days if necessary.

Question 32

A 23-year-old man presents with diffuse skin sloughing after ingestion of trimethoprim-sulfamethoxazole. Which of the following is an independent risk factor for increased mortality in the SCORe of Toxic Epidermal Necrosis (SCORTEN) illness severity scale?

A. Age > 30

B. Serum bicarbonate > 20

C. Serum glucose > 150

D. Serum BUN > 28

E. Heart rate > 90 beats/min

Answer 32

ANSWER: D

COMMENTS: Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are systemic disease processes that cause varying degrees of epidermal sloughing, with mortality ranging from 5% to 30%.

Commonly associated with drug ingestion with an immunologic basis, it is important for the provider to quickly identify and stop any potential culprit drug, as a delay in the cessation of drug administration decreases survival. Furthermore, early transfer of patients to a burn unit is the standard of care in initial management after the diagnosis of SJS/TEN is made.

The SCORTEN illness severity score was created and validated in the year 2000 as a predictor of mortality in patients with SJS/TEN. On multivariate analysis of 165 patients with SJS/ TEN, prognostic risk factors, vitals, and laboratory values (corresponding odds ratios for mortality) are as follows: age > 40 years (2.7), associated malignancy (4.4), heart rate > 120 beats per min (2.7), serum BUN > 28 mg/dL (2.5), TBSA > 30% (3.3), serum bicarbonate < 20 mmol/L (4.3), and serum glucose > 252 mmol/L (5.3).

Each independent predictor is attributed one point. Mortality ranges from 3.2% with one risk factor to over 90% with five or more risk factors.

Treatment for SJS/TEN is supportive, with wound care and monitoring in the burn ICU to prevent
additional superinfection.

Question 33

A 35-year-old male comes in following an occupational injury in which he sustained 35% full-thickness burns to his torso and upper extremities. On hospital day #2, the decision is made to perform excision of his burns with split-thickness skin grafting. Which of the following is associated with early excision and grafting?

A. Decreased mortality

B. Decreased functional outcomes

C. Increased length of stay

D. Increased cost

E. Increased number of operations

Answer 33

ANSWER: A

COMMENTS: Early excision and grafting of deep burns has been one of the great advances in burn surgery. Although universally accepted now, early excision of a large burn during the initial-stage burn shock was initially considered to be prohibitively dangerous. In 1960, a paper concluded that early excision and grafting should only be used “in experienced hands, [sic] in so far as the risks require further investigation.”

However, over the years research has clearly demonstrated the advantages of early excision of both small- and large-TBSA full-thickness burns. In 1982, researchers at the University of Washington demonstrated decreased rates of burn wound sepsis and hospitalization in patients treated by early excision (excision prior to 14 days) and grafting versus waiting for autoexcision of the eschar in TBSA burns of 20%–40%. This study was later corroborated by a 1989 prospective study by Herndon et al., which randomized patients with TBSA burns (>30%) into early excision or topical antibiotic treatment until autoexcision. Mortality in the early-excision group was 9% versus 45% in the delayed-excision cohort.

Additional studies have shown decreases in mortality, intensive care stays, and hospital expenditure. Theories on the survival advantage of the early removal of full-thickness burns include removal of a hyperinflammatory focus and prevention of secondary wound infection.

Question 34

A 22-year-old man suffers partial- and full-thickness burns to 45% TBSA in a gas explosion while at work. Which of the following is most accurate regarding surgical management of his wounds?

A. Assessment of the depth of injury on admission is accurate enough for definitive surgery to be planned in more than 90% of cases.

B. Fascial excision allows grafts to be placed over a healthy muscle bed and is the preferred approach to burns on the hands and dorsal surface of the feet.

C. Sheet (unmeshed) grafting is preferred for areas subjected to repeated shear, thus making it the choice for extensive burns on dorsal surfaces.

D. Excision of burn wounds within 24 h of injury should not be performed due to the effects of hypothermia on coagulopathy and the time required to assess for adequacy of resuscitation.

E. Widely meshed grafts minimize the degree of wound contraction associated with the use of split-thickness grafts

Answer 34

ANSWER: D

COMMENTS: Excision of deep partial- and full-thickness burn wounds should be done after resuscitation is complete and the patient is normothermic and hemodynamically stable.

Although the advantages of early excision and grafting are well described, watchful waiting is appropriate to observe for healing in burns of indeterminate depth to avoid unnecessary grafting to those portions that will heal.

Wounds expected to heal within 3 weeks are best treated with antimicrobial dressings, whereas full-thickness burns, as well as deep partial-thickness wounds with delayed healing, require grafting.

Fascial excision refers to the removal of burned skin and subcutaneous tissue down to the level of the fascia, frequently with electrocautery. This approach provides a bed that readily takes graft and is usually easy to define.

However, such deep debridement often results in fragile, esthetically displeasing grafts.

Tangential excision involves sequentially cutting away eschar with a handheld knife with a depth guard until viable dermis or subcutaneous tissue is present as noted by diffuse punctate bleeding. Experience is important in judging the depth of excision required to support a graft.

Hemostasis may be achieved with a combination of electrocautery, suture ligature, thrombin spray, direct pressure, and dilute epinephrine solution in gauze pads.

Skin grafts may be full thickness for smaller grafts or split thickness for larger ones, depending on the amount of dermis present when harvested.

Harvesting is most commonly done with a dermatome. Thinner grafts will heal with greater contraction, but thicker grafts come at the cost of loss of dermis at the donor site, which leads to prolonged times until healing and increased donor site scarring.

Meshing of grafts (ranging from 1:1 to 4:1) may be used to allow egress of fluid from the wound bed through the graft and to increase the area covered when donor sites are limited. Widely meshed grafts are associated with prolonged healing, increased scarring, and more contraction than are less meshed or sheet grafts.

A variety of dressings may be placed over grafted areas, the goal of which is to maintain contact of the graft with the wound bed to allow graft survival, prevent shearing, and facilitate subsequent vascular ingrowth into the graft.

Question 35

Which of the following is correct regarding the skin substitutes used in burn reconstruction?

A. Cultured epidermal autografts have dramatically increased survival in patients with nearly 100% TBSA burn injuries.

B. Allografting to burn wound sites is limited to temporary closure because of eventual rejection of the graft by the patient.

C. Porcine xenograft has the advantage of better early vascularization and engrafting after placement as a result of decreased antigenicity in comparison to most cadaveric human allografts.

D. Use of the Integra Dermal Regeneration Template is advantageous because of lower rates of wound infection than with early autografting in heavily colonized burn wounds.

E. Vascularization of porcine xenograft may be aided by the use of low-dose cyclosporine, provided that the patient is free of infectious complications at the time of placement.

Answer 35

ANSWER: B

COMMENTS: After debridement and excision of burn eschar, closure of the wound with immediate autografting, when possible is preferred.

Full-thickness skin grafts are the best possible cutaneous replacement, but they are not feasible for burns of significant size because the full-thickness donor site must be closed primarily.

Meshed split-thickness grafts may be used to cover areas larger than the donor site harvested, but for large burns and patients with limited donor sites, even meshed autografts will not be able to cover all open wounds.

Wounds not able to be autografted immediately may be covered with biologic dressings while awaiting donor site healing before reharvesting.

Human allograft has been widely used as a temporary biologic dressing. It is usually meshed to allow drainage of fluid and applied in a similar fashion to other skin grafts.

Allograft will vascularize and engraft, provide wound closure for 2 to 4 weeks, and subsequently be rejected and need to be replaced with new allograft or autograft if available. Sheets of allograft may be placed over widely meshed autograft at the time of surgery to protect grafts as the interstices epithelialize.

Porcine xenograft is cheaper and more easily stored before use, but it does not vascularize and engraft. It may be used similar to allograft for temporary biologic coverage of burn wounds, as well as for exfoliative diseases of the skin (e.g., TEN).

Cultured epidermal autografts grown from patient keratinocytes are promising as a skin substitute but are not yet in widespread availability and are associated with high cost and complexity.

Dermal substitutes such as the Integra Dermal Regeneration Template (Integra Lifesciences, Plainsboro, NJ) have seen more clinical use.

The Integra dermal template is a bilaminate composed of an outer silicone film that provides barrier function and an inner layer of type 1 collagen and chondroitin sulfate. This inner layer serves as a template for the ingrowth of autologous fibroblasts, endothelial cells, and other mesenchymal cells. After vascularization of the Integra, the silicone film is removed, and very thin autografts may be applied to the neodermis. Reported advantages include neodermis architecture similar to that of uninjured dermis, which results in improved cosmetic and functional results, as well as rapid healing of thin autograft donor sites.

Disadvantages include wound infection and increased length of time and immobilization before final autograft closure.

Question 36

Which of the following statements is correct regarding surgical anatomy and technique in operations commonly performed by burn surgeons?

A. The main concept for incisions in torso escharotomies is separating the chest eschar down the midline, allowing free expansion of each side of the torso.

B. A dermatome must be held at a 0-degree angle to the skin when initiating skin grafting.

C. A hand escharotomy is performed on the palmar side of the hand between the metacarpals.

D. Effective mechanisms to control bleeding following tangential excision of burns include diluted dressings with epinephrine, or fibrinogen and thrombin spray.

E. Disadvantages of a fascial incision include increased blood loss compared with tangential incisions.

Answer 36

ANSWER: D

COMMENTS: Three common operations performed by burn surgeons are escharotomies, burn excision, and skin grafting.

Escharotomies are performed for full-thickness burns causing life-threatening complications secondary to restricted peripheral blood flow or pulmonary compliance.

Surgeons must be aware of the appropriate anatomy to perform a fully effective procedure. For burns of the chest wall, escharotomy incisions are made on bilateral posterior axillary lines with superior borders of clavicles to inferior borders of sub- costal margins. For the hand, a hand escharotomy is performed on the dorsal side of the hand between the metacarpals.

Excision of full-thickness burns can be performed by fascial or tangential means by a variety of surgical instruments. A tangential excision will have greater blood loss than a fascial excision, which can be controlled using dressings diluted with epinephrine or fibrinogen and thrombin spray.

Skin grafting is performed in a split-thickness or full-thickness manner and must be performed appropriately for a successful graft take. Common donor sites include the thighs or back. After application of mineral oil, a dermatome is used to harvest a split-thickness skin graft.

Question 37

A 22-year-old utility company employee is found down at a job site at the base of the ladder. He has a charred wound in the left temporal region with palpable shards of skull present. His left arm is waxy and fixed in flexion. There are full- thickness burns on his left flank, the lower part of his left leg is firm, and the toes of his left foot are burned and missing. Which of the following is the correct statement regarding electrical injury?

A. The cause of the dark, reddish urine noted in the urinary catheter will most likely be revealed by computed tomography of the abdomen.

B. Signs concerning for compartment syndrome should prompt urgent escharotomy of the affected limbs.

C. Neurologic deficits that develop in a delayed fashion, weeks to months after the injury, have a better prognosis.

D. Early fascial decompression of the extremities may be important in preserving limb function.

E. Myoglobinuria is addressed by maintaining an hourly urine output of 0.5 mL/kg in adults and 1 mL/kg in children less than 20 kg.

Answer 37

ANSWER: D

COMMENTS: Electrical injuries are classified in the medical literature into low-voltage, high-voltage (>1000 V), and lightning injuries (also termed ultra-high voltage). Patients injured by electricity may, in fact, have injuries by any of the three mechanisms: flash burns from the very high temperatures generated when high- voltage current arcs through the air, flame burns because of ignition of clothing, and true electrical injury as a result of conduction of electrical current through the patient’s body.

Low-voltage injuries may cause local tissue injury but rarely lead to systemic injury.

High-voltage injuries may cause unpredictable patterns of local injury, including deep tissue destruction belied by the small size of the skin wounds, full-thickness cutaneous wounds at entry/exit sites and areas where arcing occurs across joints or flexor surfaces, and musculoskeletal injuries from severe tetanic contractions of the paravertebral and other muscle groups.

Patients with an electrical injury are at particularly high risk for associated traumatic injuries because electrical exposures frequently occur in occupational settings and may involve falls from a height. In fact, the tetanic muscle contractions caused by alternating current tend to cause “hanging up” by workers who grasp an electrical source and pull themselves in; patients who hang up and survive may do so because they subsequently fall and break contact with the current, and can suffer other injuries as a result.

Evaluation of patients suffering from a high-voltage electrical injury includes a full examination of the traumatic injury, radiographic studies, electrocardiogram, and bladder catheterization.

Patients with no loss of consciousness at the scene, no history of arrhythmias during transport, and a normal admission electrocardiogram do not require cardiac monitoring unless the severity of the injury would otherwise require it.

Deep tissue damage secondary to high-voltage current may result in unseen muscle swelling and necrosis. Neurovascular examination should document the extent of disability present at admission, and progressive deterioration in extremity function should prompt consideration of compartment release by fasciotomy.

Compartment pressures may be measured if the patient is not likely to need compartment release, but fasciotomy should be prompted by clinical grounds if significant concern exists.

Escharotomy refers to the division of band-like circumferential full-thickness burn eschars through to subcutaneous fat only.

Fixed deficits or mummified extremities may not benefit from compartment release. Pigmented urine suggestive of myoglobinuria should be treated by fluid resuscitation sufficient to produce a urine output of 100 mL/h.

Fasciotomies or even early debridement or amputation of necrotic muscle can be performed to avoid renal failure.

Urine myoglobin assays are often not immediately available, but urine that is heme positive by dipstick with no red blood cells on microscopic examination may be presumed to be myoglobinuria resulting from rhabdomyolysis; hematuria found on urinalysis should additionally prompt reconsideration of occult genitourinary trauma.

Toddlers may suffer electrical burns to the mouth from chewing on appliance cords.

Full-thickness oral burns are typically treated conservatively with attention to preserving mouth opening, and families should be counseled about the possibility of delayed facial artery bleeding after the eschar softens and falls off.

High-voltage injuries may result in progressive demyelinating injury and lead to sensory or motor loss weeks or months after the injury.

Early cataract formation has been associated with high-voltage electrical exposure.