Burns

Question 1

A 25-year-old woman with burns on 85% of the total body surface area undergoes staged wound excision but shows limited donor sites for skin grafting. Cultured epidermal autografts (CEAs) are prepared to help resurface the wounds. Which of the following properties is the primary advantage of the use of CEAs over split-thickness skin grafts?
A) Cultivation period of 1 week
B) Expansion of donor keratinocytes
C) Negligible production cost
D) Stable coverage of the lesion
E) Use of autologous materials during cell culture

Answer 1

B) Expansion of donor keratinocytes

Theoretically, cultured epidermal autografts (CEAs), also known ascultured keratinocytes, are an attractive option to help resurface large wounds, such as in the massively burned patient with limited donor sites. After obtaining a small skin biopsy, tissue is then processed ex-vivo by a commercial tissue-engineering laboratory. Within 3 weeks, keratinocytes can be expanded 10,000-fold and are ready for grafting. CEAs, however, must be grown with murine fibroblasts and fetal calf serum, both of which contain xenogeneic proteins that survive at the time of transplantation and may account for ‘rejection’ of these autografts. Furthermore, CEAs lack a dermal component and are extremely fragile, susceptible even to mild sheer forces. Finally, CEAs are very expensive, costing as much as 1,000 for every 1% of the total body surface area that is ultimately covered

Question 2

Cultured epidermal autografts - Cons

Answer 2

CEAs must be grown with murine fibroblasts and fetal calf serum, both of which contain xenogeneic proteins that survive at the time of transplantation and may account for ‘rejection’ of these autografts.
CEAs lack a dermal component and are extremely fragile, susceptible even to mild sheer forces
CEAs are very expensive, costing as much as 1,000 for every 1% of the total body surface area that is ultimately covered

Question 3

How long must CEAs be expanded before grafting?

Answer 3

3 weeks

Question 4

A 40-year-old man has second-and third-degree burns involving 55% of the total body surface area. Which of the following immunologic responses is most likely in this patient during the first week after injury?
A)Downregulation of integrins
B) Downregulation of cytokines tumor necrosis factor (TNF)-a and IL 1&8
C) Increased B-lymphocyte function
D) Increased levels of circulating immunoglobulins
E) Increased T-suppressor lymphocyte function

Answer 4

E) Increased T-suppressor lymphocyte function

Nearly all aspects of immune function are affected by thermal injury, and the effect is directly related to the extent of the injury. Burns that are on greater than 30% of the total body surface area result in a greater systemic inflammatory response because of circulating cytokines and immune mediators.

Both humoral and cellular-mediated immunity are impaired by thermal injury and are manifested by diminished activation of complement and depressed levels of circulating immunoglobulins; upregulation of integrins and the cytokines TNF-a and interleukins 1 and 8 (IL-1, IL-8); decreased B-lymphocyte, natural killer cell, and T-helper lymphocyte function; and an increased number and activity of T-suppressor lymphocytes. These changes normalize during the ensuing 2 to 3 weeks in patients whose course is uncomplicated.

Antiprostaglandins, either topical (such as 70% aloe cream) or oral (ibuprofen 12 mg/kg), are beneficial to block the cascade of arachidonic acid by cyclooxygenase and the inflammatory process. Beneficial effects of antiprostaglandins include vasodilatation and anti platelet aggregation.

Rapid rewarming decreases further tissue damage as it halts both direct injury and continued release of secondary mediators. Submersion of the injured part in 104°F (40°C) water for 15 to 30 minutes is ideal. This maneuver stops ice crystal formation and reverses the deleterious effects of vasoconstriction. Use of radiant heat sources in frostbite can lead to iatrogenic injury due to uneven thawing and, in unusual cases, secondary thermal burn to insensate tissue. Before and after photographs are shown.

Question 5

Immunity vs burns

Answer 5

Both humoral and cellular-mediated immunity are impaired by thermal injury and are manifested by diminished activation of complement and depressed levels of circulating immunoglobulins; upregulation of integrins and the cytokines TNF-a and interleukins 1 and 8 (IL-1, IL-8); decreased B-lymphocyte, natural killer cell, and T-helper lymphocyte function; and an increased number and activity of T-suppressor lymphocytes. These changes normalize during the ensuing 2 to 3 weeks in patients whose course is uncomplicated.

Question 6

Functions of TNF-a and IL-1 and IL-8

Answer 6

TNF-a and IL-1 and IL-8 increase neutrophil chemotaxis into the wound as well as the upregulation of cell surface integrin receptors.

Question 7

A 59-year-old postal worker comes to the emergency department because of numbness and discoloration of the right thumb. He says he was outdoors for 8 hours in a temperature of -15°F (-26°C) and had taken ibuprofen before arrival. Physical examination shows distal bluish skin without capillary refill. A photograph of the thumb is shown. Which of the following is the most appropriate initial management?
A) Debridement or amputation of dead tissue, if necessary, to avoid infection
B) Debridement of any hemorrhagic blisters
C) Discontinue antiprostaglandins
D) Observe and allow the tissue to fully demarcate
E) Rapid rewarming with radiant heat

Answer 7

D) Observe and allow the tissue to fully demarcate

The decision to allow tissue to fully demarcate is essential in the scenario described because it is difficult to determine which tissue may survive in the immediate postinjury period. This period may be 6 months

Question 8

Clear vs hemorrhagic blisters

Answer 8

Clear blisters are debrided because they contain high concentrations of inflammatory mediators. Inflammatory mediators lead to greater tissue injury. Hemorrhagic blisters are not debrided because this may cause exposure of deep structures and increase the risk of desiccation and subsequent necrosis

Question 9

Antiprostaglandins that may be helpful in cold injury

Answer 9

topical (such as 70% aloe cream) or oral (ibuprofen 12 mg/kg),

Question 10

Actions of antiprostaglandins in cold injury

Answer 10

Antiprostaglandins, either topical (such as 70% aloe cream) or oral (ibuprofen 12 mg/kg), are beneficial to block the cascade of arachidonic acid by cyclooxygenase and the inflammatory process. Beneficial effects of antiprostaglandins include vasodilatation and anti platelet aggregation.

Question 11

Rapid rewarming vs cold injury

Answer 11

Rapid rewarming decreases further tissue damage as it halts both direct injury and continued release of secondary mediators. Submersion of the injured part in 104°F (40°C) water for 15 to 30 minutes is ideal. This maneuver stops ice crystal formation and reverses the deleterious effects of vasoconstriction.

Question 12

Radiant heat sources for frostbite

Answer 12

Use of radiant heat sources in frostbite can lead to iatrogenic injury due to uneven thawing and, in unusual cases, secondary thermal burn to insensate tissue. Before and after photographs are shown.

Question 13

A 50-year-old woman comes to the emergency department because of an itchy skin rash 2 weeks after administration of trimethoprim-sulfamethoxazole for treatment of a urinary tract infection. Temperature is 99.5°F (37.5°C), pulse rate is 110 bpm, respiratory rate is 28/min, and blood pressure is 95/60 mmHg. Oxygen saturation on pulse oximetry is 96%. Physical examination shows an exfoliating skin rash on 35% of the total body surface area. Which of the following is the most appropriate next step in management?
A) Administration of systemic corticosteroids
B) Full-thickness skin biopsy
C) Intravenous administration of immune globulin
D) Topical application of silver sulfadiazine
E) Transfer to a burn center

Answer 13

E) Transfer to a burn center

A patient who develops an exfoliating rash 1 to 3 weeks after starting a specific medication, such as trimethoprim-sulfamethoxazole (Bactrim), allopurinol, or phenytoin (Dilantin), has toxic epidermal necrolysis syndrome (TENS, also known as Stevens-Johnson syndrome) until proven otherwise. Patients with TENS often have several days’ worth of indolent and nonspecific symptoms, such as malaise, fever, and dysphagia. These symptoms progress rapidly to hemodynamic collapse, skin exfoliation, and mucosal sloughing.
Skin biopsy is pathognomonic but should not delay treatment.
Skin biopsy is pathognomonic but should not delay treatment. Administration of intravenous immune globulin and systemic corticosteroids are both controversial and may have negative effects. Application of topical silver sulfadiazine as a wound care cream is contraindicated because of the potential for exacerbation of the immune response from the sulfa moiety of this agent.

Question 14

Mortality of toxic epidermal necrolysis syndrome

Answer 14

30%

Question 15

Presentation of toxic epidermal necrolysis syndrome

Answer 15

A patient who develops an exfoliating rash 1 to 3 weeks after starting a specific medication, such as trimethoprim-sulfamethoxazole (Bactrim), allopurinol, or phenytoin (Dilantin), has toxic epidermal necrolysis syndrome (TENS, also known as Stevens-Johnson syndrome) until proven otherwise. Patients with TENS often have several days’ worth of indolent and nonspecific symptoms, such as malaise, fever, and dysphagia. These symptoms progress rapidly to hemodynamic collapse, skin exfoliation, and mucosal sloughing.

Question 16

Proposed mechanism in toxic epidermal necrolysis syndrome

Answer 16

The proposed mechanism is an acute autoimmune response to the basement membrane of epithelial structures, induced by drug exposure.

Question 17

Application of topical silver sulfadiazine cream in toxic epidermal necrolysis syndrome

Answer 17

Application of topical silver sulfadiazine as a wound care cream is contraindicated because of the potential for exacerbation of the immune response from the sulfa moiety of this agent.

Question 18

IVIG in toxic epidermal necrolysis syndrome

Answer 18

Controversial and may have negative effects.

Question 19

Corticosteroids in toxic epidermal necrolysis syndrome

Answer 19

Controversial and may have negative effects.

Question 20

Accepted modality of treatment for toxic epidermal necrolysis syndrome

Answer 20

Although many modalities of treatment have been proposed, only transfer to a burn center has been universally accepted as a priority because of the critical care and wound care necessary to impact survival.

Question 21

A 34-year-old man comes to the emergency department after sustaining electrical burns to the right upper extremity while working on high-voltage power lines. Physical examination shows full-thickness burns on the right volar forearm involving 3% of the total body surface area. Poikilothermia and pallor are noted over the affected area. Pulses are not palpable. Supplemental oxygen is administered, and fluid resuscitation is initiated. Which of the following is the most appropriate next step in management?
A) Elevation of the arm
B) Escharotomy of the volar forearm
C) Fasciotomy of the volar forearm only
D) Fasciotomy of the volar forearm and carpal tunnel release only
E) Fasciotomy of the volar forearm, including decompression of the pronator quadratus, and carpal tunnel release

Answer 21

E) Fasciotomy of the volar forearm, including decompression of the pronator quadratus, and carpal tunnel release

Following high-voltage injury with full-thickness or partial-thickness skin loss, patients may develop compartment syndrome. In such cases, immediate decompression is mandated. Patients typically show the pentad of pain, paresthesias, pallor, poikilothermia, and pulselessness. In addition to releasing the eschar and the fascia of the forearm, carpal tunnel release is important to decompress both the palmar arch and median nerve. Exploration of the deep compartment of the forearm, including the pronator quadratus, is essential, as tissue injury may increase in proximity to the radius and ulna due to the heat generated by passage of the electrical current.

Question 22

Signs of compartment syndrome

Answer 22

Pentad of pain, paresthesias, pallor, poikilothermia, and pulselessness.

Question 23

Relevance of the radius/ulna in upper extremity electrical injury

Answer 23

Exploration of the deep compartment of the forearm, including the pronator quadratus, is essential, as tissue injury may increase in proximity to the radius and ulna due to the heat generated by passage of the electrical current.

Question 24

A 19-year-old woman comes to the office for a follow-up examination 18 months after skin grafting for burns over 25% of her total body surface area that includes the face, neck, chest,and shoulders. Physical examination shows persistent restriction of neck excursion and lateral range of motion. A photograph is shown. Which of the following is the most appropriate management?
A) Compression therapy
B) Corticosteroid injection
C) Silicone sheeting
D) Skin grafting 
E) Z-plasty tissue rearrangement

Answer 24

E) Z-plasty tissue rearrangement

The patient described has a condition that is common among burn patients with significant burns to the neck area; that is, contracture band formation, even after primary attempts at skin grafting. Contractures are produced not only by absolute skin loss and/or skin contraction along a straight line scar, but also by the differential growth rate between the burn scar andthe rest of the adjacent normal skin and tissues, especially in younger patients.

There are various techniques used to release contractures. Management depends on both the location of the contracture as well as the availability of unaffected adjacent skin. Methods of release include tissue expansion, local and distant flaps, ?alphabet plasties? (Z, W, V-Y, etc.), and skin grafting. The most appropriate option for the patient described is a Z-plasty, especially as she has failed a prior attempt at skin grafting. Through soft-tissue rotation, Z-plasty accomplishes three things: (1) lengthens a contracted scar, (2) breaks up a straight line, and (3) shifts soft-tissue contour

Question 25

What does a Z-plasty accomplish?

Answer 25

Through soft-tissue rotation, Z-plasty accomplishes three things:

(1) lengthens a contracted scar
(2) breaks up a straight line
(3) shifts soft-tissue contour

Question 26

Pros/cons of skin grafts for soft tissue contractures

Answer 26

The advantageof skin grafts, in general, is the transfer of new skin from a previously uninjured area of the body to the area in need with low donor site morbidity, though full-thickness grafts generally have larger donor site morbidity than split grafts. The disadvantage of skin grafts is that they tend to recontracture, necessitating further release through reoperation, as in the scenario described. Prolonged periods of postoperative physiotherapy and splinting are required to maximize aesthetic and functional results.

Question 27

A 55-year-old man is brought to the emergency department after sustaining electrical burns. He has numbness of the left hand; pulse in the hand and sensation to touch are diminished. Which of the following is the most effective management to restore perfusion to the left hand? 
A ) Anticoagulation 
B ) Embolectomy 
C ) Burn excision 
D ) Escharotomy 
E ) Fasciotomy

Answer 27

E ) Fasciotomy

The patient described has a circumferential electrical injury to the forearm consistent with compartment syndrome. Fasciotomy is indicated

Question 28

Acute burn injury exceeding ____% can lead to a significant systemic response:

Answer 28

Acute burn injury exceeding 20% can lead to a significant systemic response, with release of vasoactive mediators, third spacing, increased metabolic requirement, and immune suppression. Surgical debridement and closure of the wound can limit the inflammatory process

Question 29

Timeline for escharotomy

Answer 29

Escharotomy is performed within the first 24 hours of admission.

Question 30

Which of the following skin substitutes contains foreskin-derived neonatal human fibroblasts and keratinocytes? 
A ) AlloDerm 
B ) Apligraf 
C ) Biobrane 
D ) Integra 
E ) Surgisis

Answer 30

B ) Apligraf

Apligraf is a permanent, biosynthetic, bilayered living construct of cultured foreskin-derived neonatal human keratinocytes and fibroblasts. They are cultured on a matrix consisting of bovine-type collagen.

Question 31

Apligraf

Answer 31

Apligraf is a permanent, biosynthetic, bilayered living construct of cultured foreskin-derived neonatal human keratinocytes and fibroblasts. They are cultured on a matrix consisting of bovine-type collagen.

Question 32

Alloderm

Answer 32

AlloDerm is a human cryopreserved, acellular, cadaveric, de-epidermalized dermis. The complex is immunologically inert and becomes repopulated with host fibroblasts and endothelial cells.

Question 33

Biobrane

Answer 33

Biobrane contains Type I porcine collagen peptides in a bilaminate of silicone film and nylon fabric.

Question 34

Integra

Answer 34

Integra is a temporary bilaminate composed of silicone and a matrix of cross-linked bovine tendon collagen and shark-derived glycosaminoglycans.

Question 35

Surgisis

Answer 35

Surgisis is derived from porcine small intestine and is processed into a biocompatible three-dimensional, extracellular matrix composed of collagen, noncollagenous proteins, and other biomolecules.

Question 36

A 30-year-old woman who is morbidly obese is admitted to the burn unit with partial-thickness burns on 40% of the total body surfacearea involving the trunk and lower extremity. Maintenance of which of the following is the most appropriate measure to guide proper fluid management of the patient?
A ) Arterial systolic pressure greater than 90 mmHg
B ) Cardiac output greater than 5 L/min
C ) Mean arterial pressure greater than 55 mmHg
D ) Pulse rate less than 120 bpm
E ) Urinary output of 0.5 mL/kg/h

Answer 36

E ) Urinary output of 0.5 mL/kg/h

Routine vital signs, such as blood pressure and heart rate, can be very difficult to interpret in patients with large burns.

Hourly urine output is a well-established parameter for guiding fluid management. The rate of fluid administration should be titrated to a urine output of 0.5 mL/kg/h or approximately 30 to 50 mL/h in most adults and older children (> 50 kg [110 lb]).

Question 37

UOP goals in burn patients

Answer 37

Hourly urine output is a well-established parameter for guiding fluid management. The rate of fluid administration should be titrated to a urine output of 0.5 mL/kg/h or approximately 30 to 50 mL/h in most adults and older children (> 50 kg [110 lb]).

Question 38

Maintaining UOP > 0.5 mL/kg/h in burn patients

Answer 38

The urge to maintain urine output at rates greater than 30 to 50 mL/h should be avoided. Fluid overload in the critical hours of early burn management leads to unnecessary edema and pulmonary dysfunction. It can necessitate morbid escharotomies and extend the time required for ventilator support.

Question 39

Blood pressure monitoring in burn patients

Answer 39

The formation of edema in the extremities can limit the usefulness of noninvasive blood pressure measurements. Evaluation of arterial line pressures is subject to error from peripheral vasospasm from the high-catecholamine state.

Blood pressure is not an accurate measure of tissue perfusion.

Question 40

Ensuring accuracy in monitoring UOP for burn resuscitation

Answer 40

The presence of glycosuria can result in an osmotic diuresis and lead to artificially elevated urine output values. Performing a urinalysis at some point during the first 8 hours is prudent, especially for patients with larger burns, to screen for this potentially serious overestimation of the intravascular volume.

Question 41

A 57-year-old man develops exposure keratitis, corneal ulceration, and bilateral upper and lower eyelid ectropions 2 months after sustaining burns to the head and neck during a gas grill explosion. A photograph is shown. A tracheostomy was performed at the time of the accident for inhalation injury. Which of the following is the most definitive treatment modality for this patient’s condition?
A ) Adhesion tarsorrhaphy
B ) Bilateral tarsoconjunctival flaps
C ) Frost sutures
D ) Lateral tarsal strip canthoplasty
E ) Staged upper and lower ectropion releases with skin grafts

Answer 41

E ) Staged upper and lower ectropion releases with skin grafts

The patient described requires definitive treatment of the burn ectropions, which involves release of the ectropion and resurfacing of the orbicularis muscle with high-quality skin that will resist contraction. Although full-thickness skin grafts will have less of a tendency to contract thansplit-thickness skin grafts, the shoulder and supraclavicular fossa are superior to the groin as donor sites in terms of texture and color match.

Question 42

Definitive treatment of burn ectropions

Answer 42

Definitive treatment of the burn ectropion involves release of the ectropion and resurfacing of the orbicularis muscle with high-quality skin that will resist contraction. Although full-thickness skin grafts will have less of a tendency to contract thansplit-thickness skin grafts, the shoulder and supraclavicular fossa are superior to the groin as donor sites in terms of texture and color match.

Question 43

A 42-year-old man is brought to the emergency department after being rescued from an avalanche. History includes type 2 diabetes mellitus that is well controlled by diet. He has smoked one pack of cigarettes daily for the past 10 years. Physical examination shows erythema, edema, and blistering of the right lower extremity extending from the distal tibia to the tips of the toes. Which of the following is the most appropriate first step in management?
A ) Debridement and negative pressure wound therapy
B) Hyperbaric oxygen therapy
C ) Intravenous administration of heparin
D ) Primary amputation
E ) Rewarming in a water bath 104 °F (40 °C)

Answer 43

E ) Rewarming in a water bath 104 °F (40 °C)

The mainstay of treatment for frostbite injuries is rapid rewarming by submersion of the affected body part in a water bath maintained at a constant temperature of 104 to 108 °F (40 to 42 °C)

Question 44

When is repercussion considered adequate?

Answer 44

The optimal temperature was demonstrated in controlled experiments by Entin and Baxter in 1952. Rewarming may take 20 to 40 minutes and is deemed adequate when there is evidence of distal perfusion, such as a blush.

Gradual rewarming should not be used, as this has been associated with greater tissue injury.

Question 45

A 32-year-old man is brought to the emergency department after being lost during a snowstorm in the mountains for 24 hours. Physical examination shows significant edema, loss of sensation, grayish blue discoloration, and hemorrhagic blisters on both hands and feet. Which of the following is the most appropriate initial management?
A ) Debridement of the hemorrhagic blisters
B ) Oral administration of ibuprofen
C ) Rapid cycles of freezing and thawing
D ) Rapid rewarming using a radiant heat source

Answer 45

B ) Oral administration of ibuprofen

Ibuprofen provides antiprostaglandin activity to limit the potential for secondary mediator damage.

Debridement of hemorrhagic blisters may cause exposure of the deeper structures and run the risk of desiccation and subsequent necrosis. Traditionally, early and aggressive debridement and amputation are avoided. The development of deep, dry gangrene can be allowed to declare the specific regions that must undergo amputation. On the other hand, triple-phase scanning can be used todelineate viable tissue early on and obviate prolonged demarcation.

Question 46

A 4-year-old boy has wound cellulitis, pneumonia, and bacteremia one week after sustaining burns on 38% of the total body surface area in a house fire. He undergoes debridement of the wounds. Grafting is performed to reconstruct the resulting defects. Debrided tissue is sent for culture. While awaiting the results of culture, which of the following is the appropriate empiric antibiotic therapy?
A ) Ampicillin-sulbactam, ciprofloxacin, and tobramycin
B ) Penicillin G, clindamycin, and gentamicin
C ) Vancomycin and piperacillin-tazobactam
D ) Vancomycin, piperacillin-tazobactam, and amphotericin
E ) Vancomycin, piperacillin-tazobactam, and fluconazole

Answer 46

C ) Vancomycin and piperacillin-tazobactam

The most common bacteria causing burn wound infections include methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas, and Klebsiella. Empiric antibiotic therapy for the patient described would need to cover these gram-positive cocci and gram-negative rods.

Question 47

The most common bacteria causing burn wound infections include:

Answer 47

The most common bacteria causing burn wound infections include methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas, and Klebsiella. Empiric antibiotic therapy for the patient described would need to cover these gram-positive cocci and gram-negative rods.

Question 48

An unconscious 25-year-old man is brought to the emergency department after being electrocuted while working near high-voltage power lines. The patient is resuscitated. Examination shows a 4 x 3-cm burn on the skin over the left antecubital fossa and significant swelling of the forearm. Which of the following is the most appropriate next step in management?
A ) Dressing of the affected area and observation in the burn unit
B )Excision and coverage with a local flap
C ) Excision and coverage with a split-thickness skin graft
D ) Fasciotomy of the forearm
E ) Splinting of the hand in the intrinsic plus position

Answer 48

D ) Fasciotomy of the forearm

Because bone has a high resistance, heat is generated rapidly in this area, resulting in deep tissue injury. Compartment syndrome can develop in a patient with an electrical injury because of the deep tissue injury and subsequent subfascial edema.

Question 49

A 47-year-old man has deep partial-thickness burns of the neck, trunk, and abdominal wall involving 55% of the total body surface area. Which of the following is the most effective immediate method to deliver nutrition to this patient?
A ) Ad liboral intake with high-calorie protein shakes
B ) Enteral nutrition through gastrostomy tube
C ) Enteral nutrition through nasogastric tube
D ) Parenteral nutrition through central venous catheter
E ) Parenteral nutrition through peripheral intravenous injection

Answer 49

C ) Enteral nutrition through nasogastric tube

Providing nutrition early in the management of a burn victim is critical to a successful outcome. Since the gastrointestinal tract is typically intact in a burn victim, enteral feeding is the route of choice. In massive burn patients, care must be taken to recognize gastric and/or intestinal ileus, which may complicate and inhibit the advancement of enteral feeds. Nevertheless, burn victims rarely require parenteral nutrition on a long-term basis.

Question 50

Ideal route of feeding for burn victims

Answer 50

Since the gastrointestinal tract is typically intact in a burn victim, enteral feeding is the route of choice. In massive burn patients, care must be taken to recognize gastric and/or intestinal ileus, which may complicate and inhibit the advancement of enteral feeds. Nevertheless, burn victims rarely require parenteral nutrition on a long-term basis

Question 51

A 20-year-old college student is being evaluated because of painful blistering of his toes the morning after he walked two miles in snowy weather, wearing sandals and no socks. Which of the following best describes the primary beneficial effect of ibuprofen for this patient?
A ) Control of edema
B ) Control of pain
C ) Decreased secondary tissue damage
D ) Prevention of anti platelet aggregation
E ) Speeding of demarcation

Answer 51

C ) Decreased secondary tissue damage

Thromboxane A2 is a powerful mediator of the inflammatory process responsible for secondary tissue damage in frostbite injuries. Ibuprofen blocks the cyclooxygenase cascade that results in the production of thromboxane A2. The negative effect of blockade of the cyclooxygenase is decreased production of prostaglandin I2 and E2, which are responsible for vasodilatation and antiplatelet aggregation. Although pain control is a beneficial result of the use of ibuprofen, many patients suffering from frostbite injuries require narcotic pain medications. Demarcation cannot be speeded by the use of ibuprofen and may require up to six months before amputation should be undertaken.

Question 52

What is responsible for secondary tissue damage in frostbite injuries?

Answer 52

Thromboxane A2 is a powerful mediator of the inflammatory process responsible for secondary tissue damage in frostbite injuries. Ibuprofen blocks the cyclooxygenase cascade that results in the production of thromboxane A2.

Question 53

A 48-year-old man is brought to the emergency department 40 minutes after he sustained full-thickness burns over 54% of the total body surface area. Weight is 156 lb (70 kg). According to the Parkland formula, which of the following is the most appropriate volume of fluid resuscitation for this patient during the first eight hours?
A ) 945 mL
B ) 1890 mL
C ) 3780 mL
D ) 7560 mL
E ) 15,120 mL

Answer 53

D ) 7560 mL

The Parkland formula is 4 mL * 70 kg * 54 = 15,120 mL. Half of this (7560 mL) is given over the first eight hours.

Question 54

Why are large amounts of fluid required to maintain tissue perfusion for acute burn injury?

Answer 54

Acute burn injury is characterized by inflammation and impaired microvascular integrity with resulting capillary leak. Therefore, large amounts of fluid are required to maintain tissue perfusion during this period and prevent burn shock.

Question 55

Parkland formula

Answer 55

4 mL of LR / KG per percentage burn over the first 24 hours

1/2 over the first 8 hours, 1/2 over the next 16 hours

Question 56

Rule of 9’s

Answer 56

The body is divided into regions whose surface areas are multiples of nine: head, 9%; each arm, 9%; torso, 36%; each leg, 18%.

Question 57

A 61-year-old obese woman comes to the office for follow-up examination because she has a non-healing 3-cm-diameter ulcer on the sole of the right foot. Medical history includes hypertension and type 2 diabetes mellitus. A bioengineered skin substitute consisting of a cultured dermal-epidermal matrix (Apligraf) was applied one week ago. The patient has been compliant with a strict non-weight-bearing status of the foot. Current physical examination shows minimal adherence of the graft. Which of the following is the most appropriate next step in management?
A ) Application of hydrogel and gauze dressings
B ) Application of a new biosynthetic graft matrix
C ) Coverage with a sural fasciocutaneous flap
D ) Full-thickness skin grafting
E ) Surgical debridement to fascia

Answer 57

B ) Application of a new biosynthetic graft matrix

Biosynthetic skin products, particularly Apligraf, have been shown to be effective in treatment of chronic diabetic foot ulcers when used judiciously and appropriately.

The fibroblasts and keratinocytes in the matrix secrete growth factors and stimulate wound healing and ingrowth of the surrounding tissues. One drawback of biosynthetic skin substitutes is the high cost. If completewound healing can be achieved, then cost of care is lower over the long term. A single application of a dermal matrix product is not likely to be sufficient in the treatment of a chronic wound. Abandoning the course of treatment at one week would increasethe cost of care without the potential to realize the benefit.

Question 58

Application of Apuigraft for chronic wounds

Answer 58

One drawback of biosynthetic skin substitutes is the high cost. If complete wound healing can be achieved, then cost of care is lower over the long term. A single application of a dermal matrix product is not likely to be sufficient in the treatment of a chronic wound. Abandoning the course of treatment at early (such as at one week) would increasethe cost of care without the potential to realize the benefit.

Question 59

A 62-year-old woman comes to the office for consultation regarding problems with her left eye (shown) 6 months after sustaining a 25% total body surface area (TBSA) burn that involved the face and neck. She reports that the upper eyelid turns outward, that she cannot close the eye completely, and that the eye tears excessively. These symptoms have persisted despite skin grafting several months ago by another surgeon. Physical examination confirms ectropion of the upper eyelid, lagophthalmos, and epiphora of the left eye. Which of the following is the most appropriate next step in management?
A ) Insertion of a gold weight
B ) Paramedian forehead flap
C ) Permanent lateral tarsorrhaphy
D ) Reverse tarsoconjunctival flap
E ) Skin grafting

Answer 59

E ) Skin grafting

Patients with significant burns to the periocular area commonly have ectropion with corneal exposure, even after primary attempts at skin grafting. It is clear that damaged contracted skin has left this patient ―skin short,‖ thereby preventing complete closure of the eyelid. The optimal method of eyelid reconstruction in this patient is a release of the burn scar contracture with placement of nonburned, thin, pliable skin to the area in order to bring tissue to the area,thereby correcting the underlying problem. Although multiple options for reconstruction exist, the most reasonable would involve regrafting the upper eyelid.

Question 60

A 35-year-old man is brought to the emergency department after he sustained frostbite injuries to both hands and feet when he became lost while skiing and was exposed to subfreezing temperatures. Both hands and feet are rewarmed by immersion in circulating water for 30 minutes. Which of the following is the most appropriate diagnostic tool to establish the level of amputation in this patient?
A ) Contrast MRI
B ) Noncontrast CT
C ) Noncontrast MRI
D ) Technetium-99m bone scanning
E ) Three-view plain radiography

Answer 60

D ) Technetium-99m bone scanning

The most useful tool for early prediction of the level of amputation is two-phase technetium-99m bone scanning. A retrospective study shows that an initial bone scan (as early as day 3) has excellent specificity in evaluating the severity of frostbite injury.

Question 61

Most useful tool for early prediction of the level of amputation

Answer 61

The most useful tool for early prediction of the level of amputation is two-phase technetium-99m bone scanning. A retrospective study shows that an initial bone scan (as early as day 3) has excellent specificity in evaluating the severity of frostbite injury.

Study data have shown a direct correlation between the demarcation zone of uptake in the phalanges and the eventual level of amputation (positive predictive value, 0.84). A second scan taken on approximately day 7 was more sensitive and informative. A strong correlation existed between positive uptake and eventual healing (negative predictive value, 0.99).

Question 62

A 26-year-old man is brought to the emergency department 30 minutes after sustaining injuries in a motor vehicle collision. Examination shows full-thickness burns on 28% of the total body surface area, flail chest, pelvic hematoma, and an open fracture of the right ankle. Radiographs show a fracture of the pelvis. He is intubated and mechanically ventilated. A vena cava filter is placed. Open reduction and internal fixation of the ankle fracture is performed followed by debridement of the right lower leg. A free tissue transfer is planned to cover the exposed tibia, patella, and peripatellar tendon. To avoid flap thrombosis, which of the following is the most appropriate time to perform the tissue transfer?
(A)Immediately
(B)Two days after debridement
(C)Six days after debridement
(D)Two weeks after debridement
(E)Six weeks after debridement

Answer 62

(E)Six weeks after debridement

Assuming that the patient described needs a free flap to provide coverage of the exposed knee structures, the optimal time for free tissue transfer in burn patients, following debridement, is four to six weeks after injury.

The proposed mechanism for flap thrombosis at earlier dates is the hypercoagulable state associated with burn injury.

Question 63

Optimal timing for non thermal lower extremity trauma requiring free tissue transfer

Answer 63

For nonthermal lower-extremity trauma requiring free tissue transfer, most studies support early flap reconstruction within the first week after injury. Both military and civilian injuries benefit from aggressive debridement and immediate or nearly immediate coverage

Question 64

Optimal timing for lower extremity trauma associated with burn injury, requiring free tissue transfer

Answer 64

The optimal time for free tissue transfer in burn patients, following debridement, is four to six weeks after injury.

The proposed mechanism for flap thrombosis at earlier dates is the hypercoagulable state associated with burn injury.

Question 65

A 4-year-old boy has full-thickness burns on 20% of the total body surface area. Which of the following end points is the most appropriate indicator of adequate fluid resuscitation in this patient?
(A)Cardiac index of 2.0 l/min/m2
(B)Mean arterial pressure of 60 mmHg
(C)Positive inspiratory pressure of 25 mmHg
(D)Pulmonary wedge pressure of 15 mmHg
(E)Urine output of 1.0 ml/kg/h

Answer 65

(E)Urine output of 1.0 ml/kg/h

Intravenous fluid resuscitations usually are required for patients with smaller burns (10%–20%).

BSA burns must be estimated using the pediatric modifications in the Lund-Browder classification, which demonstrates the relatively larger head and small thigh in pediatric patients. This results in higher weight-based calculations for resection volume (nearly 6 ml/kg per percentage burn), leading some to advocate a BSA-based resuscitation in addition to the required maintenance infusion as described by the Galveston Shriners Hospital (Galveston, TX) pediatric formula. Other centers, such as the Shriners Burn Institute in Cincinnati, use the Parkland formula with the addition of a maintenance rate.

Recommended end points are also higher in children, with urine output closer to 1 ml/kg/hr being a more appropriate goal.

Question 66

Recommended UOP in pediatric burn patients

Answer 66

Recommended end points are higher in children, with urine output closer to 1 ml/kg/hr being a more appropriate goal.

Question 67

At what point should a patient be switched to adult resuscitation parameters?

Answer 67

hildren approaching 50 kg are probably better served by adult resuscitation parameters (30-50 ml/hr urine output) and calculations

Question 68

AccuChecks and burns in pediatric patients

Answer 68

One concern with this population is the modest hepatic glycogen reserves, which can be exhausted quickly and sometimes require the change from Ringer’s lactate to dextrose 5% in Ringer’s lactate to prevent life-threatening hypoglycemia. For this reason, AccuChecks every four to six hours should be routine during the hypermetabolic state, especially for patients with larger burns.

Question 69

A 26-year-old man is brought to the emergency department 90 minutes after sustaining injuries in a house fire. The patient says he has a headache. Physical examination shows second-degree burns to the face and anterior chest equaling 10% of the total body surface area, singed nasal vibrissae, and carbonaceous sputum. Ventilation with 100% oxygen is started; SaO2is 95%. Whichof the following is the most appropriate next step in diagnosis?
(A)Fiberoptic bronchoscopy
(B)Measurement of carboxyhemoglobin level
(C)Radiograph of the chest
(D)Spiral CT
(E)Ventilation-perfusion lung scan

Answer 69

(A)Fiberoptic bronchoscopy

Question 70

Most frequent cause of death in burn patients

Answer 70

Inhalation injury

Question 71

% fatality of smoke inhalation + cutaneous burns

Answer 71

Smoke inhalation in combination with cutaneous burns is fatal in 30% to 90% of patients.

Question 72

Standard for diagnosis of inhalation injury

Answer 72

The current standard for diagnosis of inhalation injury in most major burn centers is fiberoptic bronchoscopy. Findings include the presenceof soot, charring, mucosal necrosis, airway edema, and inflammation. Widespread use of this technique has led to a two-fold increase in the diagnosis of inhalation injury.

Question 73

Carbon monoxide poisoning @ 30%

Answer 73

Levels greater than 30% can cause headache, nausea, and behavioral disturbances.

Question 74

Carbon monoxide poisoning @ 40%

Answer 74

Levels greater than 40% cause a pathognomonic cherry-red skin discoloration.

Question 75

Carbon monoxide poisoning and O2 administration

Answer 75

Carbon monoxide levels in the patient receiving 100% O2 are a poor indicator of injury. It takes one hour for levels to fall by one half while patients breathe 100% oxygen

Question 76

When are signs of inhalation injury evidenced on radiographs?

Answer 76

It usually takes five to 10 days before findings of focal infiltrates or diffuse pulmonary edema are evident on radiographs.

Question 77

Xenon ventilation-perfusion lung scan

Answer 77

A xenon ventilation-perfusion lung scan is the most definitive study for diagnosis of inhalation injury. It demonstrates areas of decreased alveolar gas washout, which identifies sites of small airway obstruction caused by edema or fibrin cast formation; however, the study is time-consuming. It requires transport of the patient from the emergency department or burn unit to the radiology department and is therefore less practical.

Question 78

A 34-year-old man sustained deep burns to the entire body surface area above the level of the waist one year ago. Initial management of the burns included excision and split-thickness skin grafting. During his recovery, release of burn scar contractures will most likely be needed in which of the following anatomic regions?
(A)Axilla
(B)Elbow
(C)Hand
(D)Neck
(E)Trunk

Answer 78

(D)Neck

According to multicenter study data, neck contracture release is performed 24% of the time, followed by axilla (20%), elbow (11%), trunk (11%), knee (10%), and hand (9%). Release procedures are often performed in more than one site. The most common factors prompting contracture release are decreased range of motion or impaired function, unsatisfactory cosmetic appearance, pain, and pruritus.

Question 79

Most common sites where contractures are released

Answer 79

Neck: 24%
Axilla: 20%
Elbow: 11%
Trunk: 11%
Knee: 10%
Hand: 9%

Question 80

A 5-year-old boy is brought to the emergency department after he sustained burns in a gasoline fire. Physical examination shows burns to 70% of the total body surface area, including the right ear (shown). Which of the following is the most appropriate initial management of the burns to this patient’s ear?
(A)Application of mafenide acetate (Sulfamylon) cream and auto-amputation
(B)Costochondral reconstruction with a temporoparietal flap
(C)Debridement and coverage with a retroauricular pocket flap
(D)Excision and full-thickness skin grafting
(E)Excision and unmeshed split-thickness skin grafting

Answer 80

(A)Application of mafenide acetate (Sulfamylon) cream and auto-amputation

Ear burns are usually aggressively managed with mafenide acetate (Sulfamylon) cream, monitoring for chondritis, and allowing the severely burned region to auto-amputate. This is especially true for large total body surface area (TBSA) burns such as the one sustained by the patient described, where large areas of excision and grafting must be done to save the patient’s life.This is largely a problem of ear deformity, not function, and therefore has a lower priority.

Question 81

Management of ear burns

Answer 81

Ear burns are usually aggressively managed with mafenide acetate (Sulfamylon) cream, monitoring for chondritis, and allowing the severely burned region to auto-amputate. This is especially true for large total body surface area (TBSA) burns such as the one sustained by the patient described, where large areas of excision and grafting must be done to save the patient’s life.This is largely a problem of ear deformity, not function, and therefore has a lower priority.

Question 82

Sulfamylon and the ear following burn injury

Answer 82

Mafenide acetate (Sulfamylon) cream is the best topical antibiotic agent suitable for the ear because it penetrates the eschar and cartilage. It is applied twice daily. The eschar should not be completely debrided, as it acts as a biological dressing that prevents desiccation.

Question 83

A 14-year-old boy is brought to the office because he is unable to extend the proximal interphalangeal (PIP) joint of the long finger of the dominant right hand beyond 60 degrees of flexion. Six months ago, he sustained partial-thickness burns to the palmar surface of the long finger. The remaining fingers were spared. He has been performing active and passive range of motion exercises under the guidance of a therapist. Examination shows a thick scar extending the full width of the palmar skin and from the mid proximal phalanx to the distal interphalangeal flexion crease. With full passive flexion of the metacarpophalangeal (MCP) joint, the PIP joint can be extended nearly completely. Which of the following is the most appropriate management?
(A)Continued hand therapy and observation
(B)Daytime dynamic extension splinting and nighttime static extension splinting
(C)Injection of a corticosteroid into the scar and continued hand therapy
(D)Release of the contracture and full-thickness skin grafting
(E)Z-plasty lengthening of the scar and continuous static extension splinting

Answer 83

(D)Release of the contracture and full-thickness skin grafting

n the patient described, the severe PIP joint contracture shows adequate correction with MCP joint flexion, implying a primary derangement of the skin. Involvement of deeper structures (volar plate, collateral ligaments) would not correct with altered position of the MCP joint.

As a primary intervention, the optimal treatment of the patient described is division of the contracted cord and interpositional, full-thickness skin grafting.

No role for corticosteroid.
Z-plasty wis good in narrow scars, but would be difficult / ineffective in wide scars.

Question 84

Initial treatment for hand contracture following a burn

Answer 84

For initial treatment and early, immature contracture management, therapy and dynamic splinting are critical interventions. In an established,mature burn scar, attempts at stretching the scar (continued hand therapy or dynamic extension splinting) will be unlikely to correct the defect

Question 85

A 19-year-old man who sustained burns to 40% of the total body surface area at 4 years of age comes to the burn clinic for consultation regarding correction of the scalp defect shown. Physical examination shows a large area of patchy alopecia of the temporal scalp and hypertrophic scarring. Which of the following is the most appropriate surgical procedure for reconstruction of this patient’s scalp?
(A)Hair transplantation with micrografts and mini grafts
(B)Orticochea flap
(C)Serial excision and closure
(D)Temporoparietooccipital (Juri) flap
(E)Tissue expansion

Answer 85

(E)Tissue expansion

The patient shown has a large (>25 cm2) parietal scalp defect that resulted from a flame burn. Tissue expansion is the preferred method for secondary reconstruction of a large parietal scalp defect. Approximately 50% of scalp can be reconstructed with expanded scalp tissue, although this may require multiple stages.

Question 86

Reconstruction of a large parietal scalp defect

Answer 86

Tissue expansion

Question 87

How much scalp can be reconstructed with expanded scalp tissue?

Answer 87

50%

Question 88

Complication rates of expander use for parietal scalp defect

Answer 88

Expander complication rates may be as high as 25% and may include infection, exposure, extrusion, and device failure.

Question 89

Hair- Direct closure in a staged manner with serial excision or as a single-stage procedure with rotation advancement flaps is appropriate for:

Answer 89

Direct closure in a staged manner with serial excision or as a single-stage procedure with rotation advancement flaps is appropriate for small to medium-sized defects of the anterior and parietal scalp.

Question 90

Temporoparietooccipital flaps

Answer 90

Temporoparietooccipital flaps as described by Juri are optimally suited for reconstruction of large defects of the anterior scalp.

Question 91

Orticochea flaps are classically described for:

Answer 91

Orticochea flaps are classically described for reconstruction of large defects of the occipital scalp. They are not useful for parietal defects because tissue advancement from the contralateral parietal scalp up over the vertex is often inadequate for defect closure

Question 92

A 37-year-old man is brought to the emergency department because he has pain, paresthesia, and difficulty extending the fingers of the right hand one hour after he sustained a high-voltage electrical injury. Physical examination shows burns over 20% of the total body surface area with an entrance wound in the right forearm and an exit wound in the left lower abdomen. Which of the following is the most appropriate management?
(A)Decompressive fasciotomy of the right forearm
(B)Elevation and splinting of the right upper extremity
(C)Infusion of calcium gluconate
(D)Serial physical examinations of the right upper extremity over eight hours
(E)Tangential excision of burned tissue and coverage with allografts

Answer 92

(A)Decompressive fasciotomy of the right forearm

Compartment pressures greater than 30 mmHg, worsening paresthesia, pain on passive range of motion, or pulselessness in an extremity mandate immediate decompression as part of acute resuscitation after electrical injury.

Question 93

Compartment syndrome of the upper extremity, when pressures are > _______

Answer 93

30 mm Hg

Question 94

Which of the following is most appropriate in preparation of deep partial-thickness burn injuries to the hand before skin grafting?
(A)Application of topical enzymatic debriding agents
(B)Delay of surgical intervention until natural separation of eschar occurs
(C)Excision of the skin to the viable subcutaneous fat
(D)Tangential excision until pinpoint bleeding occurs
(E)Whirlpool hydrotherapy until indeterminate areas are declared

Answer 94

(D)Tangential excision until pinpoint bleeding occurs

Question 95

Delay of surgical intervention until natural eschar separation:

Answer 95

Delay of surgical intervention until natural eschar separation has been shown to significantly increase mortality, increase hospitalization, increase incidence of burn wound sepsis, and also contribute to burn scar hypertrophy and contracture.

Question 96

Name of knife in burn surgery

Answer 96

Goulian knife

Question 97

Bleeding at upper layers of dermis and treatment

Answer 97

The points of bleeding are close together in the upper layers of the dermis, known as the papillary dermis. Burn wounds at this level are partial-thickness injuries that heal adequately with a biologic barrier material.

Question 98

Bleeding at lower layers of dermis and treatment

Answer 98

If tangential excision proceeds to the reticular dermis, which is in the deeper dermal layers, bleeding points become more widely separated. At these deeper levels of tangential excision, the yellow hue of subcutaneous fat may become visible. Tangential excision to this deeper layer is best treated with a biologic barrier material followed by skin grafting.

Question 99

A previously healthy 55-year-old man is brought to the emergency department three hours after sustaining partial-thickness scald burns to the arms, torso, and legs, comprising 35% of the total body surface area. He has smoked one half pack of cigarettes daily for the past 20 years. The patient is breathing comfortably on room air and oxygen saturation is99%. On physical examination, he is alert, calm, and cooperative. The patient is admitted to the hospital for wound care. Three days after the injury, respiratory distress develops and he is intubated. Which of the following is the most likely mechanism of respiratory failure in this patient?
(A)Aspiration pneumonia
(B)Inflammatory interstitial edema
(C)Inhalation injury
(D)Pulmonary embolism
(E)Severe chronic obstructive pulmonary disease

Answer 99

(B)Inflammatory interstitial edema

His normal breathing and oxygen saturation on admission rule out a severe underlying pulmonary process. Inhalation injury is common in fires but not scald injury.

Question 100

A 25-year-old firefighter is transferred to the burn unit for management of burns to the hands 10 days after he sustained burns to 85% of the total body surfacearea (TBSA). His condition is stable, and vital signs are within normal limits. He has undergone multiple excision and grafting procedures. Current physical examination shows large areas of exposed tendon over the dorsum of both hands after excision of the burned skin. Partial-thickness burns of adjacent tissue are noted. Because of the extent of this patient’s TBSA burns, regional and free tissue flaps are precluded. The most appropriate intervention for wound coverage is application of which of the following?
(A)Allograft skin graft
(B)Dermal regeneration template (Integra)
(C)Expansion of adjacent tissue
(D)Porcine xenografts
(E)Temporary biosynthetic skin substitute (Biobrane)

Answer 100

(B)Dermal regeneration template (Integra)

The patient described requires wound coverage with dermal regeneration template (Integra). Exposure of the extensor tendons precludes the use of skin grafts and no local flaps are available in this patient’s burned hands because of adjacent scarring. Allograft skin would have similar problems of adherence to the exposed tendons and would require overly epidermal autografts. Regional and free flaps are also unavailable.

The use of tissue expansion to increase the size of full-thickness grafts and to improve the availability of local flaps while decreasing donor site morbidity has been suggested. The patient described is not a candidate for this procedure because of the local partial-thickness burns. Even if the local tissue was uninjured and could be expanded, the presence of exposed tendons does not allow for the protracted time associated with expander reconstruction. Expanders in the upper extremity have also been associated with a high rate of complications such as infection and extrusion.

Question 101

Expanders and upper extremity tendon exposure

Answer 101

Not enough time for expansion - need faster tendon coverage.

Expanders in the upper extremity are also associated with a high rate of complications such as infection and extrusion.

Question 102

Biobrane and porcine xenograft - use in burn wounds

Answer 102

Both Biobrane and porcine xenograft may be used for coverage of partial-thickness burns. Both allow wound re-epithelialization, at which point the Biobrane or allograft can be peeled off.

Question 103

Bilaminate skin substitutes emulate what in burn wounds?

Answer 103

Bilaminate skin substitutes such as Integra (collagen-glycosaminoglycan dermis/Silastic epidermis) and Alloderm regenerative tissue matrix (autologous-allogeneic dermis) plus a split-thickness skin graft emulate the desirable properties of dermis and epidermis, particularly with respect to pore size. The outer membrane requiresa small pore size to act as a barrier to microorganisms while allowing water vapor permeability. The inner layer requires a larger pore size to permit ingrowth of granulation tissue from the wound bed.

Question 104

Bilaminate skin substitutes such as Integra (collagen-glycosaminoglycan dermis/Silastic epidermis) and Alloderm regenerative tissue matrix (autologous-allogeneic dermis) plus a split-thickness skin graft can be used for what type of burn wounds?

Answer 104

Partial thickness burns

Question 105

Alloderm vs Integra for skin grafting

Answer 105

Both require thin epidermal grafts for coverage, though only Alloderm is able to support immediate skin grafting.

Question 106

A 43-year-old man who works as an electrical lineman is brought to the emergency department one hour after he sustained a high-voltage electrical injury. Physical examination shows a 1.5 x 2-cm area of eschar on the palmar aspect of the right hand and an area of charred tissue on the right foot that is presumed to be the exit wound. Pulses in all extremities are within normal limits. Evaluation of the hand shows absence of sensation and muscle weakness. Which of the following diagnostic studies is most appropriate to evaluate the extent of muscle damage in the patient’s hand?
(A)Angiography
(B)CT
(C)Electromyography
(D)MRI
(E)Technetium-99m scanning

Answer 106

(D)MRI

High-voltage electrical injuries (greater than 1000 volts) to the extremities present a difficult diagnostic dilemma. Often, the injury is significantly more extensive than indicated by the cutaneous examination.

MRI is the most appropriate choice because it is the most sensitive of the tests listed. MR images do not demonstrate tissue edema

Question 107

How many volts is a high voltage electrical injury?

Answer 107

Greater than 1000 volts

Question 108

Sensation in electrical burns

Answer 108

In electrical burns, sensation often cannot be used as an adequate judge because paresthesia is common because of the low resistance of the nerve to electric current.

Question 109

A 25-year-old woman who sustained burns to 85% of the total body surface area in a house fire undergoes staged excision of the wound but has limited donor sites for skin grafting. Cultured epidermal autografts are applied for resurfacing. Which of the following is the most significant advantage of this procedure?
(A) Cost effectiveness
(B) Expansion of donor keratinocytes
(C) Immediate availability of autogenous materials
(D) Short cultivation period
(E) Stable coverage of grafted wounds

Answer 109

(B) Expansion of donor keratinocytes

Cultured epidermal autografts (CEAs), also known as cultured keratinocytes, are theoretically attractive to help resurface large wounds, such as in the massively burned patient with limited donor sites. Within three weeks, keratinocytes can be expanded 10,000-fold and are ready for grafting. CEAs, however, must be grown with murine fibroblasts and fetal calf serum, both of which contain xenogeneic proteins, which survive to transplantation and may account for rejection of these autografts. Furthermore, CEAs lack a dermal component and are extremely fragile, susceptible even to mild sheer forces. Finally, CEAs are very expensive, costing as much as $13,000 for every 1% total body surface area ultimately covered.

Question 110

A 26-year-old man is brought to the burn unit after sustaining severe thermal burns and inhalation injury. Increase in which of the following elements on peripheral blood smear is most predictive of a fatal outcome in this patient?
(A) C-reactive protein
(B) Erythroblasts 
(C) Erythrocyte sedimentation rate
(D) Hemoglobin
(E) Leukocyte count

Answer 110

(B) Erythroblasts

A recent study from Germany studied the prognostic significance of erythroblasts in peripheral blood and their correlation with a fatal outcome from a burn injury. Erythroblasts are not normally present in peripheral blood, except in the fetus and the newborn.

Question 111

Erythroblasts are present normally in the peripheral blood when?

Answer 111

Fetus and newborn peripheral blood

Question 112

Erythroblasts are present in the peripheral blood in what type of injury?

Answer 112

A recent study from Germany studied the prognostic significance of erythroblasts in peripheral blood and their correlation with a fatal outcome from a burn injury.

(May also be associated with cancer, infection, severe hematopoietic diseases.)

Question 113

A 26-year-old man who works at a glass factory comes to the emergency department 30 minutes after both hands and forearms were exposed to hydrofluoric acid in a chemical accident. Immediately after the injury, the hands were wrapped in gauze. Examination of the hands and upper extremities shows erythema and severe pain. Which of the following is the most appropriate next step in management?
(A) Application of topical polyethylene glycol solution to the burned areas
(B) Lavage of the burned areas with sodium bicarbonate solution
(C) Subcutaneous injection of calcium gluconate into the burned areas
(D) Intravenous infusion of sodium bicarbonate
(E) Excision of burned tissue to the level of the subcutaneous fascia

Answer 113

(C) Subcutaneous injection of calcium gluconate into the burned areas

The best treatment for this patient with hydrofluoric acid topical burns is calcium gluconate injection. Hydrofluoric acid, which is commonly used in industrial occupations, produces burn when it comes into contact with skin. Initial treatment of lavagewith copious amounts of water reduces the amount of acid in the skin

Question 114

Initial treatment of hydrofluoric acid burn

Answer 114

Copious amounts of water

Question 115

What happens to hydrofluoric acid after it is on the skin?

Answer 115

Hydrofluoric acid exposure causes soluble fluoride ions to traverse the skin into the subcutaneous tissue,where it results in tissue liquefaction necrosis. Fluoride ions also bind magnesium and calcium, resulting in hypomagnesemia and hypocalcemia.

Question 116

What electrolyte abnormalities occur with hydrofluoric acid exposure?

Answer 116

The fluoride ions leech calcium and magnesium from the bones, causing cellular death and producing severe pain that may not develop until several hours after initial exposure. In addition, the cellular death leads to the release of potassium, resulting in hypocalcemia, hypomagnesemia, and hyperkalemia.

Question 117

Appropriate treatment of hydrofluoric acid burn

Answer 117

Appropriate treatment would consist of subcutaneous or arterial infiltration (into the burned site) of calcium or magnesium gluconate to inactivate the fluoride ions.

Question 118

Indication of appropriate therapeutic levels when treating hydrofluoric acid injury

Answer 118

Application of calcium or magnesium gluconate inactivates fluoride ions from hydrofluoric acid burns. This binding of fluoride ions immediately reduces pain in the site and can be used as an indication of appropriate therapeutic levels.

Question 119

A 35-year-old man is brought to the emergency department two hours after he sustained second-and third-degree burns to the entire anterior abdomen, chest, and lower extremities. Weight is 65 kg (143 lb). Which of the following is the most appropriate hourly volume of fluid resuscitation over the next six hours?
(A) 400 ml
(B) 800 ml
(C) 1200 ml
(D) 1600 ml
(E) 2000 ml

Answer 119

(C) 1200 ml

In this case, the TBSA is 18% for the anterior thorax + (18% _ 2) for both lower extremities, for a total of 54%.

Question 120

What burns are counted for the Parkland formula?

Answer 120

2nd and 3rd degree

Question 121

Parkland formula

Answer 121

Parkland formula:
4 cc x Kg x % TBSA
1st half in 8 hrs, rest in 16 hrs.

*time from initial insult

Question 122

Rule of 9’s

Answer 122

In an adult, TBSA is determined by the ―Rule of Nines, as follows:
Head = 9%
Each upper extremity = 9%
Anterior thorax (chest + abdomen) = 18%
Posterior thorax (chest + abdomen) = 18%
Each lower extremity = 18%
Groin = 1%

Question 123

A 35-year-old man is brought to the emergency department because of deep burn injury to the dorsum of the index, middle, and ring fingers of the dominant left hand (shown) resulting from direct contact with a hot motorcycle engine during a motor vehicle collision. On tangential excision, tendons are exposed in each finger and loss of the paratenon is noted. Which of the following is the most appropriate surgical management? 
(A) Split-thickness skin grafting
(B) Dorsal metacarpal artery flaps
(C) Cross-finger flaps 
(D) Reverse radial forearm flap
(E) Groin flap

Answer 123

(D) Reverse radial forearm flap

Because the paratenon has been removed, immediate split-thickness skin grafting will result in areas of graft loss. Dressing changes could beperformed followed by grafting on a granulated bed. This method of treatment risks tendon desiccation while awaiting granulation tissue.

A reverse radial forearm flap would be the best choice for resurfacing the dorsal hand and fingers because it is soft, thin, and compliant. This may be most safely accomplished in stages with syndactylization performed at a second stage. This flap, however, has been longitudinally split to simultaneously resurface two areas of the hand. The two main disadvantages of this flap include the sacrifice of a major artery and an unaesthetic and potentially unstable grafted donor site.

Question 124

Disadvantage of the reverse radial forearm flap

Answer 124

The two main disadvantages of this flap include the sacrifice of a major artery and an unaesthetic and potentially unstable grafted donor site.

Question 125

The groin flap is based on:

Answer 125

Either the superficial circumflex iliac artery or the superficial inferior epigastric artery

Question 126

Cross finger flaps

Answer 126

Cross-finger flaps use dorsal skin of adjacent fingers to resurface palmar defects.

Question 127

Variation of cross-finger flap for dorsal defects

Answer 127

A variation of the cross-finger flap can be used to resurface a dorsal defect. This requires de-epithelialization of the flap and then skin grafting of the deeper surface of the flap.

Question 128

Dorsal metacarpal artery flaps

Answer 128

Dorsal metacarpal artery flaps can be useful in reconstructing dorsal hand and proximal finger defects. To repair a dorsal finger defect more distally, a reverse dorsal metacarpal artery flap could be used.

Question 129

A 10-year-old girl who sustained an electrical burn to the right upper extremity 10 days ago has undergone multiple debridements of the distal volar forearm since that time. The residual volar forearm wound is clean and measures 4 x 8 cm. Full-thickness skin loss is noted, as well as segmental loss of the flexor carpi ulnaris tendon. The ulnar nerve is exposed but appears in continuity. The patient has sensory loss in the ulnar nerve distribution and no ulnar intrinsic hand function. Which of the following is the most appropriate management?
(A) Daily whirlpool therapy and dressing changes
(B) Full-thickness skin grafting
(C) Resection of the exposed ulnar nerve and sural nerve grafting
(D) Flap coverage
(E) Tendon transfers and flap coverage of the wound

Answer 129

(D) Flap coverage

This child’s wound requires flap coverage. Vascularized tissue in the form of local or distant flaps is recommended for coverage of exposed vital structures suchas nerves, blood vessels, tendons, and bone. Therefore, wound care regimens alone and skin grafting are inadequate treatment options.

Early repair or grafting of the ulnar nerve is not indicated due to the inability to predict the amount of recovery at this early stage. Children also heal significantly better than adults, particularly in cases of nerve injury. For the same reason, tendon transfer is not indicated at this early juncture. However, appropriate splinting and therapy should be used while awaiting recovery of the nerve to prevent the claw deformity associated with low ulnar nerve palsy.

Question 130

A 25-year-old man who works as an electrician is brought to the emergency department by ambulance one hour after he fell from a ladder and grabbed a high-tension power line carrying approximately 50 kV with his right hand. Pulse rate is 120/min and blood pressure is 120/70 mmHg. Physical examination shows a burn mark over the right palm and a burn wound over the right scapula. No distal pulses are palpable. Which of the following is the most appropriate initial management of the wound to the upper extremity?
(A) Splinting of the hand and wrist in a position of function and elevation
(B) Topical application of mafenide and an occlusive dressing
(C) Escharotomy
(D) Fasciotomy
(E) Arterial grafting to the radial artery segment

Answer 130

(D) Fasciotomy

In the presence of such a significant injury, fasciotomy should be performed because continued muscle necrosis and swelling will certainly result in compartment syndrome. Decompression of the median nerve at the wrist should be ensured at the time of forearm fasciotomy. Other mainstays of treatment of electrical injuries to the upper extremity are repeated debridements of necrotic muscle and early flap coverage to decrease the incidence of amputation,infection, and renal failure.

Escharotomy is the treatment for full-thickness thermal burns to the hand and arm.

Question 131

Sulfamylon is efficacious in burns where penetration of ________ is required.

Answer 131

Mafenide acetate solution (Sulfamylon) would have efficacy for thermal burns in which penetration of cartilage is required.

Question 132

According to the American Burn Association guidelines, which of the following patients has a major burn injury requiring triage to a specialized burn center?
(A) 4-year-old boy with partial-thickness burn on the dorsal aspect of the forearm
(B) 16-year-old girl with partial-thickness burn over the shoulders and upper back
(C) 40-year-old man with type 1 diabetes mellitus and full-thickness perineal burn
(D) 55-year-old woman with full-thickness burns of the volar aspect of the right arm

Answer 132

(C) 40-year-old man with type 1 diabetes mellitus and full-thickness perineal burn

Question 133

Criteria for transfer to a major burn center: Patients 50 yo

Answer 133

2nd or 3rd degree over 10% of TBSA

Question 134

Criteria for transfer to a major burn center: All ages (other than 50 yo)

Answer 134

2nd or 3rd degree over 20% TBSA

Question 135

Criteria for transfer to a major burn center: Location on the body

Answer 135

Hands, face, feet, genitalia, perineum, over major joints

Question 136

Criteria for transfer to a major burn center: Amount of 3rd degree burn

Answer 136

3rd degree burn >5% TBSA at any age

Question 137

Criteria for transfer to a major burn center: Type of injury

Answer 137

Concomitant inhalation injury, significant electrical or chemical injury

Question 138

Criteria for transfer to a major burn center: Type of patients

Answer 138

Patients with significant preexisting medical disorder that complicates management, such as diabetes mellitus or heart disease;
Patients who might have special social or emotional needs or require long-term support, as in a child who has been abused or neglected

Question 139

A 24-year-old man has a mentosternal contracture (shown above) one year after sustaining burns over 90% of the total body surface area. Which of the following reconstructive interventions is the most appropriate management of the contracture?
(A) Scar release and coverage with a dorsal scapular island flap
(B) Scar release and coverage with a free scapular flap
(C) Scar release and skin graft coverage with a thin split-thickness skin graft harvested from the scalp
(D) Scar release and use of the dermal regeneration template (Integra)

Answer 139

(D) Scar release and use of the dermal regeneration template (Integra)

A mentosternal contracture usually requires a wide scar release and extensive tissue coverage. However, this patient who has burns over nearly the total body surface area has limited donor sites. Therefore, the dermal regeneration template should be used with thin split-thickness grafting. This reconstructive intervention provides an acceptably low rate of long-term recurrence of contracture and it uses available donor sites.

STSG has an unacceptable rate of contracture recurrence.

Scar release and coverage with a free scapular flap or dorsal scapular island flap are ideal options for reconstruction.

Question 140

Ideal treatment of a mentosternal contracture associated with burn injury

Answer 140

Scar release and coverage with a free scapular flap or dorsal scapular island flap are ideal options for reconstruction.

If unburned skin is unavailable, use of a dermal regeneration template is a possibility.

Question 141

Topical silver sulfadiazine may produce which of the following sequelae?
(A) Carbonic anhydrase inhibition
(B) Granulocyte reduction
(C) Methemoglobinemia
(D) Staining of the skin on contact

Answer 141

(B) Granulocyte reduction

Silver sulfadiazine (Silvadene) is a commonly used topical burn agent. It may result in granulocyte reduction (neutropenia and thrombocytopenia).

Question 142

Side effect associated w/ Silvadene

Answer 142

Silver sulfadiazine (Silvadene) is a commonly used topical burn agent. It may result in granulocyte reduction (neutropenia and thrombocytopenia).

Question 143

Side effect associated w/ Sulfamylon

Answer 143

Carbonic anhydrase inhibition may occur with mafenide acetate (Sulfamylon), resulting in metabolic acidosis.

Question 144

Side effect associated w/ silver nitrate

Answer 144

Silver nitrate is an excellent topical agent and has no gram-negative resistance; however, brown staining of skin and equipment is common and methemoglobinemia may rarely occur.

Question 145

A 30-year-old man sustains burns over 42% of the total body surface area and is resuscitated using the Parkland (Baxter) burn formula. Five percent albumin is added to the resuscitation fluid 24 hours after the injury to achieve which of the following?
(A) Maintenance of intravascular volume 
(B) Normalization of intravascular pH
(C) Nutritional support
(D) Provision of coagulation cofactors

Answer 145

(A) Maintenance of intravascular volume

Acute burn resuscitation using the Parkland (Baxter) formula is based on the patient’s physiologic response to injury. Burns cause a leak in the capillary endothelium, which results in excessive protein loss. By 24 hours after the burn injury, the capillary leak is largely resolved. At that time, 5% albumin is added to the resuscitation fluid to help maintain intravascular volume.

Question 146

Capillaries vs burn injury

Answer 146

Burns cause a leak in the capillary endothelium, which results in excessive protein loss. By 24 hours after the burn injury, the capillary leak is largely resolved.

Question 147

An 87-year-old man sustained a third-degree scald injury to the proximal forearm one hour ago. Early excision of the wound is performed, and the resultant 15 H 15-cm defect is covered using the dermal regeneration template (Integra). On which postoperative day should removal of the top silicone layer and placement of an autograft be performed?
(A) 1
(B) 7
(C) 14
(D) 21

Answer 147

(D) 21

Integra consists of a collagen-glycosaminoglycan layer covered by a silicone occlusive layer and can be used as a dermal substitute until it is replaced by the host’s own fibroblasts and endothelial cells. After the collagen-glycosaminoglycan layer is fully revascularized, the silicone layer can be removed and an autograft can be used for epidermal closure. This typically occurs at three weeks (on postoperative day 21) but may be done later, when full revascularization is eviden

Question 148

When can the silicone layer be removed from Integra, and why?

Answer 148

After the collagen-glycosaminoglycan layer is fully revascularized, the silicone layer can be removed and an autograft can be used for epidermal closure. This typically occurs at three weeks (on postoperative day 21) but may be done later, when full revascularization is evident.

Question 149

A 45-year-old farmer has worsening ulceration of the right cornea two days after anhydrous ammonia was splashed in his eyes. Immediately after this accident, the patient’s eyes were washed with saline for 45 minutes. Which of the following is the most appropriate explanation for the worsening of this patient's condition?
(A) Bacterial infection
(B) Heat from the examining light
(C) Liquefaction necrosis
(D) Scar tissue

Answer 149

(C) Liquefaction necrosis

Liquefaction necrosis is the most likely cause of the worsening eye injury. Because anhydrous ammonia is an alkaline solution, it can denature and dissolve proteins and lyse cell membranes. This increases the penetration of the alkaline solution into the eye, furthering the damage.

Question 150

Anhydrous ammonia vs the eye

Answer 150

Because anhydrous ammonia is an alkaline solution, it can denature and dissolve proteins and lyse cell membranes. This increases the penetration of the alkaline solution into the eye, furthering the damage.

Question 151

A 35-year-old man is brought to the emergency department after sustaining burns covering 40% of the total body surface area (TBSA). Physical examination shows burns to the face and chest, facial edema, and singed nasal hairs. He has stridor; respirations are 24/min. With the patient receiving 100% oxygen, pulse oximetry is 98%; arterial blood gas analysis shows a carbon monoxide level of 30%. Which of the following is the most appropriate next step in management?
(A) Bronchoscopy
(B) Cricothyroidotomy
(C) Escharotomy of the chest
(D) Hyperbaric oxygen therapy
(E) Intubation

Answer 151

(E) Intubation

Question 152

Differentiating between oxyhemoglobin and carboxyhemoglobin

Answer 152

Because pulse oximetry cannot differentiate between oxyhemoglobin and carboxyhemoglobin, artificially high readings are often obtained even in patients with carbon monoxide toxicity.

Question 153

Half life of carboxyhemoglobin

Answer 153

The half-life of carboxyhemoglobin at an inspired oxygen fraction (FIO2) of 0.21 is 240 minutes, but at an FIO2 of 1.0, the half-life improves to 30 minutes

Question 154

Signs of potential carbon monoxide poisoning

Answer 154

Smoke inhalation and potential carbon monoxide poisoning should be suspected in any patient who has sustained facial burns and has carbon deposits within the oropharynx, singeing of facial hair, or carbonaceous sputum. O2 readings can be falsely high.

Question 155

Initial management of potential carbon monoxide poisoning

Answer 155

Administration of 100% O2 w/a nonrebreather mask; this decreases the half life of carboxyhemoglobin.

Question 156

When to intubate a patient with carbon monoxide poisoning:

Answer 156

Any patient who has a carbon monoxide level of 30% or higher on arrival in the emergency department: Intubation should be performed immediately because coma and respiratory depression may occur with levels of 40% to 50%, and death can occur at levels of 50% or higher. Patients who have dyspnea, stridor, tachypnea, and/or swelling of the tongue or oropharynx, or who are using accessory respiratory muscles, should also undergo immediate intubation. If progressive swelling of the airway is a concern during fluid resuscitation, intubation should be considered.

Question 157

In a patient who sustained burns over 35% of the total body surface area four hours ago, which of the following is the most important factor in development of shock?
(A) Dilation of the peripheral vasculature
(B) Hypovolemia
(C) Myocardial depression
(D) Paralytic ileus
(E) Renal failure

Answer 157

(B) Hypovolemia

In an untreated major thermal burn, the most important factor in the initial development of shock is hypovolemia. Thermal injury disrupts capillary endothelial integrity and alters membranes. In a major burn, these actions occur even in unburned tissue because of circulatory and microcirculatory dysfunction. They lead to plasma leakage from the circulation, which results in decreased plasma volume, cardiac output, and urine output and increased systemic vascular resistance.

Dilation of the peripheral vasculature can cause shock later if sepsis occurs but is not a factor in the initial development of shock. Myocardial depression can develop later in shock if a systemic inflammatory response, severe hypovolemia, or sepsis occurs. However, it is not a factor initially.

Question 158

In an untreated major thermal burn, the most important factor in the initial development of shock is:

Answer 158

Hypovolemia.

Question 159

A 55-year-old man who weighs 90 kg (198 lb) is brought to the emergency department eight hours after sustaining first-degree burns to the head and neck and second-and third-degree burns to the entire anterior trunk and both lower extremities. According to the Parkland formula, the most appropriate management is fluid resuscitation with administration of lactated Ringer’s solution for the next eight hours at a rate of how many milliliters per hour?
(A) 607 mL/hr
(B) 709 mL/hr
(C) 1215 mL/hr
(D) 1823 mL/hr
(E) 2127 mL/hr

Answer 159

(D) 1823 mL/hr

In this patient, the burn of the anterior trunk is assigned a value of 18%, and each lower extremity burn is 18%, for a TBSA burn of 54%. First-degree burns, such as those of the head and neck, are not included in the TBSA calculation.

A 90-kg patient who has burns involving 54% TBSA will require 19,440 mL of fluid during the first 24 hours: 9720 mL during the first eight hours and 4860 mL in both the second and third eight-hour periods. Because he received no fluid during the first eight hours immediately after injury, 14,580 mL of lactated Ringer’s solution (9720 mL + 4860 mL) should be administered over the next eight hours to adequately resuscitate this patient. Divided into eight-hour totals, the solution is infused at a rate of 1823 mL/hr.

Question 160

A 38-year-old man sustained frostbite of the right hand four days ago. Examination shows necrosis distal to the metacarpophalangeal (MP) joints. Three-phase bone scanning shows viability of the proximal phalanx of each finger. Which of the following is the most appropriate management?
(A) Amputation at the level of the distal interphalangeal joints and primary closure
(B) Amputation at the level of the MP joints and primary closure
(C) Amputation at the level of the MP joints and radial forearm flap reconstruction
(D) Amputation at the level of the proximal interphalangeal (PIP) joints and groin flap reconstruction
(E) Amputation at the level of the PIP joints and second metacarpal artery flap reconstruction

Answer 160

(D) Amputation at the level of the proximal interphalangeal (PIP) joints and groin flap reconstruction

The level of skin loss does not always correlate with the level of bone viability. A three-phase bone scan can be used to determine at which level the bone is viable. Amputation of nonviable bone is performed along with amputation of the nonviable soft tissue. To salvage the bone, well-vascularized coverage is required, with either a pedicle flap or a free flap.

Amputation at the level of the PIP joints and second metacarpal artery flap reconstruction is inappropriate because a second metacarpal artery flap would be of insufficient length to cover the open area.

Question 161

Which of the following is a physiologic manifestation of shock following acute burn injury?
(A) Decreased cardiac output
(B) Decreased systemic vascular resistance
(C) Increased peripheral blood flow
(D) Increased plasma volume
(E) Increased urine output

Answer 161

(E) Increased urine output

Decreased urine output is caused by inadequate fluid resuscitation and occurs as a response to decreased tissue perfusion and increased systemic vascular resistance. Aggressive volume replacementis required during the first 24 to 48 hours after injury to restore intravascular fluid.

Question 162

A 26-year-old man who weighs 80 kg (176 lb) is brought to the emergency department three hours after sustaining superficial burns involving 20% total body surface area (TBSA), partial-thickness burns involving 15% TBSA, and full-thickness burns involving 25% TBSA. According to the Parkland formula, which of the following is the most appropriate method of fluid resuscitation for this patient?
(A) Administration of lactated Ringer’s solution 800 mL/hr for the next eight hours
(B) Administration of lactated Ringer’s solution 1300 mL/hr for the next five hours
(C) Administration of hypertonic saline solution 1000 mL/hr for thenext 12 hours
(D) Administration of hypertonic saline solution 1500 mL/hr for the next five hours
(E) Administration of hypertonic saline solution 600 mL/hr for the next eight hours

Answer 162

(B) Administration of lactated Ringer’s solution 1300 mL/hr for the next five hours

An 80-kg patient who has burns involving 40% TBSA (second-degree burns involving 15% TBSA and third-degree burns involving 25% TBSA) will require 12,800 mL of fluid during the first 24 hours: 6400 mL during the first eight hours and 3200 mL in both the second and third eight-hour periods. Because he received no fluid during the first three hours immediately following injury, 6400 mL of lactated Ringer’s solution, or 1280 mL/hr, should be administered over the next five hours in order to adequately resuscitate the patient.

Question 163

Silver sulfadiazine is administered topically to a patient with severe burns of the trunk and upper extremities. Which of the following is the most likely adverse effect?
(A) Hyponatremia
(B) Metabolic acidosis
(C) Metabolic alkalosis
(D) Neutropenia
(E) Pain with application

Answer 163

(D) Neutropenia

The most likely adverse effect of treatment of severe burns with topical application of silver sulfadiazine (Silvadene) is neutropenia, a self-limiting condition that is not thought to increase mortality in burn patients. Silver sulfadiazine is an effective treatment because it has a broad spectrum of activity and a low incidence of development of resistant organisms. Application is painless, and wound dressings are not required.

Question 164

A 24-year-old woman has been hospitalized for the past week because she has toxic epidermal necrolysis syndrome involving 90% of total body surface area (TBSA) with sparing of the lower legs and feet. She has been mechanically ventilated, and her hands have been splinted in a functional position except during passive occupational therapy. Following discontinuation of the ventilation, this patient’s hands should be splinted for how long to prevent contractures?
(A) 6 weeks
(B) 3 months
(C) 6 months
(D) 1 year
(E) No additional splinting is required

Answer 164

(E) No additional splinting is required

Patients with toxic epidermal necrolysis syndrome have sloughing of the skin at the dermal-epidermal junction. However, because injury occurs only to the level of the superficial dermis, theskin will heal without contracture. Therefore, no additional splinting is required following discontinuation of ventilation. Long-term sequelae of this condition include complications involving the eyes and fingernails and changes in skin pigmentation.

Question 165

Contractures from toxic epidermal necrolysis syndrome

Answer 165

Patients with toxic epidermal necrolysis syndrome have sloughing of the skin at the dermal-epidermal junction. However, because injury occurs only to the level of the superficial dermis, theskin will heal without contracture. Therefore, no additional splinting is required following discontinuation of ventilation.

Question 166

Etiology of toxic epidermal necrolysis syndrome

Answer 166

Although it is thought to be caused by an adverse reaction to an antibiotic, anti-inflammatory agent, or anticonvulsant, other factors, including viral, bacterial, and fungal infections and neoplasms, have also been implicated.

Question 167

An otherwise healthy 25-year-old man sustains second-and third-degree burns over 60% of total body surface area (TBSA). Which of the following immunologic responses is LEAST likely in this patient?
(A) Activation of helper T lymphocytes
(B) Increased circulating immunoglobulin G (IgG) level
(C) Increased interleukin-7 (IL-7) level
(D) Redistribution of T lymphocytes in the peripheral blood
(E) Suppression of circulating T lymphocytes

Answer 167

(B) Increased circulating immunoglobulin G (IgG) level

One immunologic response anticipated in this 25-year-old man who has sustained a 60% TBSA burn is impairment of cell-mediated immunity resulting from impairment of T-lymphocyte function. This manifests in burn patients as a delay in allograft rejection, suppression of the graft-versus-host response, and development of skin hypersensitivity reactions. Alterations in T-lymphocyte function include overall suppression of circulating T lymphocytes and a redistribution of T lymphocytes within peripheral blood and tissue compartments.

Question 168

Manifestation of impaired T-lymphocyte function in burn patients

Answer 168

Impairment of T-lymphocyte function in burn patients manifests as a delay in allograft rejection, suppression of the graft-versus-host response, and development of skin hypersensitivity reactions.

Question 169

Changes in T-lymphocyte function associated with burn injury

Answer 169

Alterations in T-lymphocyte function include overall suppression of circulating T lymphocytes and a redistribution of T lymphocytes within peripheral blood and tissue compartments.

Question 170

Immunoglobulins and burn injuries

Answer 170

Although all classes of immunoglobulins are decreased, immunoglobulin G (IgG) levels exhibit the greatest decrease. This decrease can be attributed to plasma leakage, increased protein turnover, and decreased synthesis of IgG by B lymphocytes.

Question 171

Interleukin-7 and burn injury

Answer 171

Interleukin-7 levels are increased during the first week after injury; this results in a decrease in the proliferative capacity of B lymphocytes.

Question 172

A 26-year-old man is brought to the emergency department with significant pain in the forearms 90 minutes after spilling hydrofluoric acid on his forearms at work. Immediately after the accident, the affected areas were copiously irrigated with water.The most appropriate initial management is topical administration of which of the following agents?
(A) Calcium gluconate gel
(B) Mineral oil
(C) Polyethylene glycol
(D) Silver nitrate
(E) Silver sulfadiazine

Answer 172

(A) Calcium gluconate gel

The most appropriate initial management is copious irrigation of the involved areas with water or saline followed by administration of calcium gluconate.This agent, which neutralizes the hydrofluoric acid by binding to the affected fluoride ions, can be applied topically as a gel, infused intra-arterially, or infiltrated beneath the burn eschar. Because relief of pain is a primary goal of treatment, analgesic and anesthetic agents should not be administered, as the patient will be unable to judge the pain-relieving effect of the calcium gluconate

Question 173

Pain relief and hydrofluoric acid injury

Answer 173

Because relief of pain is a primary goal of treatment, analgesic and anesthetic agents should not be administered, as the patient will be unable to judge the pain-relieving effect of the calcium gluconate.

Question 174

Cause of pain in hydrofluoric acid injury

Answer 174

The fluoride ions leech calcium and magnesium from the bones, causing cellular death and producing severe pain that may not develop until several hours after initial exposure. In addition, the cellular death leads to the release of potassium, resulting in hypocalcemia, hypomagnesemia, and hyperkalemia.

Question 175

Application of mineral oil is appropriate for patients with ______ burns.

Answer 175

Application of mineral oil is appropriate for patients with phenol burns. Irrigation with water is contraindicated in these patients because it can dilute the phenol, resulting in deeper penetration and increased tissue damage.

Question 176

Treatment of creosol burns

Answer 176

Creosol burns should be treated with topical application of polyethylene glycol.

Question 177

A 30-year-old man is brought to the emergency department after sustaining second-degree burns of the trunk involving 10% total body surface area (TBSA). The burns are cleansed, and several blisters are debrided. In order to provide antimicrobial activity, which of the following dressings should be applied to the wounds?
(A) Fibronectin-coated skin substitute (Transcyte)
(B) Porous collagen-glycosaminoglycan membrane (Integra)
(C) Silicone membrane-nylon fabric composite (Biobrane)
(D) Silver-coated wound dressing (Acticoat)

Answer 177

(D) Silver-coated wound dressing (Acticoat)

Treatment of partial-thickness burns can be accomplished through cleansing of the burn and application of either an antimicrobial or occlusive dressing. Most patients are treated with silver sulfadiazine (Silvadene); however, if a sulfa allergy is present, bacitracin, polymyxin/bacitracin (Polysporin), or mupirocin (Bactroban) can be used. Acticoat is a dressing material coated with a thin soluble layer of silver ion; it reportedly provides antimicrobial activity for as long as five days. The greatest advantage is a decrease in the number of dressing changes, with a subsequent decrease in pain, as well as decreased cost.

Biobrane and Transcyte are occlusive dressings that can be used for management of clean second-degree burns as long as they are applied within the first 24 hours. These dressings do not provide antimicrobial activity.

Question 178

Treatment of partial thickness burns: dressing

Answer 178

Treatment of partial-thickness burns can be accomplished through cleansing of the burn and application of either an antimicrobial or occlusive dressing. Most patients are treated with silver sulfadiazine (Silvadene); however, if a sulfa allergy is present, bacitracin, polymyxin/bacitracin (Polysporin), or mupirocin (Bactroban) can be used.

Question 179

Acticoat

Answer 179

Acticoat is a dressing material coated with a thin soluble layer of silver ion; it reportedly provides antimicrobial activity for as long as five days. The greatest advantage is a decrease in the number of dressing changes, with a subsequent decrease in pain, as well as decreased cost.

Question 180

Biobrane

Answer 180

Biobrane consists of a nylon fabric containing chemically bound collagen that is partially imbedded in a silicone film. As blood and serum clot within the nylon fabric, it adheres to the wound until epithelialization occurs, and then it sloughs.

Question 181

Transcyte

Answer 181

Transcyte consists of cultured human dermal fibroblasts on a semipermeable membrane bonded to nylon mesh. The mesh allows for growth of the dermal tissue, and the membrane forms a synthetic epidermis.

Question 182

Administration of anti-inflammatory agents to patients who have sustained frostbite is most likely to result in which of the following beneficial effects?
(A) Decreased production of prostaglandin I2
(B) Decreased production of thromboxane B2
(C) Increased production of prostaglandin F2a
(D) Increased production of prostaglandin I2

Answer 182

(B) Decreased production of thromboxane B2

The prostaglandins thromboxane B2 and prostaglandin F2a are thought to induce microvascular thrombosis because they cause plateletaggregation and vasoconstriction. In contrast, the prostaglandins I2 and E2 have antiplatelet activity, resulting in vasodilation. It is thought that the frostbite injury increases production of thromboxane B2 and decreases production of prostaglandin I2,resulting in an imbalance in favor of microvascular thrombosis.

Question 183

Thromboxane B2

Answer 183

Thought to induce microvascular thrombosis because it causes platelet aggregation and vasoconstriction.

Question 184

Prostaglandin F2a

Answer 184

Thought to induce microvascular thrombosis because it causes platelet aggregation and vasoconstriction.

Question 185

Prostaglandin I2

Answer 185

Antiplatelet activity, resulting in vasodilation

Question 186

Prostaglandin E2

Answer 186

Antiplatelet activity, resulting in vasodilation

Question 187

It is thought that frostbite injury does what to prostaglandins, to create an imbalance in favor of microvascular thrombosis?

Answer 187

It is thought that the frostbite injury increases production of thromboxane B2 and decreases production of prostaglandin I2, resulting in an imbalance in favor of microvascular thrombosis.

Question 188

Pros/cons of COX inhibitors for frostbite

Answer 188

Pros: Administration of these agents will decrease production of thromboxane B2 and prostaglandin F2a and thus block their harmful effects.

Cons: An adverse effect of these agents is their inhibition of prostaglandin I2 and prostaglandin E2 production, which limits their protective effect

Question 189

Monoclonal antibodies have been shown to limit the depth of burn injury by inhibiting neutrophil adhesion in which of the following zones?
(A) Zone of adherence
(B) Zone of coagulation
(C) Zone of hyperemia
(D) Zone of stasis

Answer 189

(D) Zone of stasis

Question 190

Burn injury: Zone of coagulation

Answer 190

The zone of coagulation is that area of the skin that is exposed to the highest temperature, resulting in irreversible, uniform necrosis of cells. This zone involves the burn eschar and extends downward.

Question 191

Burn injury: Zone of stasis

Answer 191

The zone of stasis surrounds the zone of coagulation; in this area, the cells sustain less direct injury initially. Instead, progressive injury occurs following the development of ischemia and subsequent impairment of blood flow. This zone is characterized by the formation of microthrombi within platelets, endothelial swelling, neutrophil adherence, deposition of fibrin, and vasoconstriction, leading to eventual cell death.

This zone is potentially reversible

Question 192

Burn injury: Zone of hyperemia

Answer 192

In the zone of hyperemia, there is vasodilation and increased blood flow caused by vasoactive mediators. Cellular injury in this zone is minimal and is completely reversible.

Question 193

The zone of adherence: clinical significance in lipectomy

Answer 193

The zone of adherence describes anatomic regions within the body in which skin and subcutaneous tissue are connected to the underlying fascia. It is important for the surgeon to recognize these zones when planning and performing suction lipectomy, as excessive suctioning may result in contour deformities.

Question 194

Reversibility of burn injury zones

Answer 194

Zone of coagulation: Irreversible
Zone of stasis: Potentially reversible
Zone of hyperemia: Completely reversible

Question 195

A 40-year-old man sustains deep partial-thickness and full-thickness burns over 45% total body surface area (TBSA). Following fluid resuscitation for 24 hours, his temperature is 38.9%C (102.1%F), pulse rate is 120 bpm, respirations are 24/min, and blood pressure is 105/60 mmHg. Serum leukocyte count is 18,000/mm3 and urine output is 70 mL/hr. Which of the following is the most likely cause of these findings?
(A) Bronchopneumonia
(B) Burn wound sepsis
(C) Inadequate fluid resuscitation
(D) Inadequate pain control
(E) Systemic inflammatory response

Answer 195

(E) Systemic inflammatory response

Bronchopneumonia would be unlikely in a patient who sustained burn injuries only 24 hours ago and more often occurs in the second week following injury. Burn wound sepsis occurs when proliferating microorganisms exceed 105 per gram of tissue and can be characterized by fever, tachycardia, and leukocytosis, but again this would not appear within the first 24 hours after injury. Inadequate fluid resuscitation is unlikely in a patient with adequate urinary output. Inadequate pain control would cause tachypnea and tachycardia, but not fever or leukocytosis

Question 196

SIRS can be caused by:

Answer 196

Soft-tissue trauma, bacteremia, sepsis, ischemia, or pancreatitis

Question 197

SIRS typically occurs in patients who have burns of what percent TBSA?

Answer 197

SIRS typically occurs in patients who have burns of more than 30% total body surface area (TBSA); the cell damage caused by the burn often incites the inflammatory reaction.

Question 198

The diagnosis of SIRS can be made in any patient with:

Answer 198

2 of:

1. T 38.5C
2. HR >90
3. RR >20/min or pCO2 12,000 or >10% bands

Question 199

38.5 C = F

Answer 199

101.5 F

Question 200

Burn wound sepsis occurs when proliferating microorganisms exceed _____ per gram of tissue a

Answer 200

Burn wound sepsis occurs when proliferating microorganisms exceed 10^5 per gram of tissue

Question 201

To minimize the risk for hypertrophic scar formation and subsequent skin contractures in a patient who has sustained partial-thickness burns of the neck, attempts at healing by second intention should be limited to a maximum of how many weeks?
(A) 1
(B) 2
(C) 3
(D) 4
(E) 6

Answer 201

(C) 3

To minimize the risk for development of hypertrophic scars and subsequent skin contractures in a patient who has sustained partial-thickness burns of the neck, the wound should not remain open for more than three weeks.

Question 202

To minimize the risk for development of hypertrophic scars and subsequent skin contractures in a patient who has sustained partial-thickness burns of the neck, the wound should not remain open for more than:

Answer 202

To minimize the risk for development of hypertrophic scars and subsequent skin contractures in a patient who has sustained partial-thickness burns of the neck, the wound should not remain open for more than three weeks.

Question 203

A 25-year-old laborer sustains a burn of the dorsal aspect of the dominant right hand in a fire. Physical examination shows a deep partial-thickness burn that involves the entire dorsal aspect of the hand. Which of the following is the most appropriate management?
(A) Early excision of the burn wound and split-thickness skin grafting
(B) Coverage of the burn wound with a silicone membrane-nylon fabric composite (Biobrane)
(C) Aggressive topical wound care and occupational therapy
(D) Excision of the burn wound and coverage with a groin flap
(E) Excision of the burn wound and delayed split-thickness skin grafting

Answer 203

(A) Early excision of the burn wound and split-thickness skin grafting

In this patient who has sustained a deep partial-thickness burn of the hand, the most appropriate management is early excision of the burn eschar followed by split-thickness skin grafting over the excised portions.

Coverage with a groin flap is an excessive, unnecessary procedure in this patient. Skin grafting should be delayed only if the depth and extent of the patient’s burn injuries are unknown. In these situations, a waiting period of seven days may be beneficial.

Question 204

A 47-year-old man sustains a high-voltage electrical burn injury to the left upper extremity; a photograph is shown above. Physical examination shows swelling and tenseness of the forearm; there is no circumferential eschar. An exit wound is noted on the left foot. Adequate fluid resuscitation has been performed, and the patient is stable. Which of the following is the most appropriate immediate management of the right forearm and hand?
(A) Observation
(B) Splinting
(C) Escharotomy
(D) Fasciotomy
(E) Amputation

Answer 204

(D) Fasciotomy

Fasciotomies of the hand and forearm should be performed immediately for tissue salvage; the surgeon should continue to assess the viability of the tissue in the hand and forearm following fasciotomy.
Observation is obviously inadequate and even dangerous in a burn patient with compartment syndrome.

Question 205

A 2-year-old child has the findings shown in the photograph above six days after sustaining a full-thickness burn injury to the left hand when the hand was immersed in boiling water. Silver sulfadiazine dressings have been applied since the time of injury. Which of the following is the most appropriate next step in management?
(A) Continued use of silver sulfadiazine dressings for three weeks
(B) Tangential excision and coverage with split-thickness skin grafts
(C) Tangential excision and coverage with full-thickness skin grafts
(D) Fascial excision and coverage with full-thickness skin grafts
(E) Coverage with cryopreserved acellular dermal homograft and epidermal grafts

Answer 205

(B) Tangential excision and coverage with split-thickness skin grafts

In this 2-year-old child who has a full-thickness burn, the most appropriate management is tangential excision to a level at which punctate bleeding occurs, followed by split-thickness skin grafting. The depth of the burn can be determined by serial examination; in this case, after six days, the wound is not vascularized and has not become epithelized. Because burns that have not healed 21 days after initial injury are associated with a significant risk for hypertrophic scarring and contracture, this child’s burn should be excised tangentially to the level of punctate bleeding. In addition, early skin grafting decreases the risk for scarring and permanent stiffness in patients with burns of the hand and increases the rehabilitation potential.

Any available full-thickness skin for grafting would most likely not be sufficient for coverage of this full-thickness burn involving most of the hand and forearm.

Question 206

Burns that have not healed _____ days after initial injury are associated with significant risk of:

Answer 206

Burns that have not healed 21 days after initial injury are associated with a significant risk for hypertrophic scarring and contracture.

Question 207

Inadequate fluid resuscitation in a burn patient is most likely to result in which of the following conversion mechanisms?
(A) Zone of coagulation to zone of hyperemia
(B) Zone of coagulation to zone of stasis
(C) Zone of stasis to zone of coagulation
(D) Zone of stasis to zone of hyperemia

Answer 207

(C) Zone of stasis to zone of coagulation

The zone of coagulation lies in the center of the wound and is characterized by irreversible tissue destruction. It is immediately surrounded by the zone of stasis, an area of decreased perfusion with demonstrated damage to the microvasculature. The surrounding zone of hyperemia sustains the least amount of damage.

Question 208

Zones of injury in burns vs timing of resuscitation

Answer 208

During the first 48 hours following burn injury, patients who are not properly resuscitated are at increased risk for conversion of the zone of stasis to a zone of coagulation. In contrast, if appropriate resuscitation is begun immediately, the zone of stasis can be reversed, potentially preventingthe development of necrosis.

Question 209

A 33-year-old man who weighs 80 kg is brought to the emergency department eight hours after sustaining deep partial-thickness burns involving 25% total body surface area (TBSA) and full-thickness burns involving 15% TBSA. According to the Parkland formula, how many milliliters (mL) of crystalloid should be administered for initial fluid resuscitation over the next eight hours?
(A) 3200
(B) 6400
(C) 9600
(D) 12,800
(E) 16,000

Answer 209

(C) 9600

An 80-kg patient who has burns involving 40% TBSA will require 12,800 mL of fluid during the first 24 hours: 6400 mL during the first eight hours and the remaining 3200 mL in both the second and third eight-hour periods. Because he received no fluid during the first eight hours immediately following injury, 9600 mL of crystalloid should be administered over the next eight hours in order to adequately resuscitate the patient.

Question 210

In a patient who sustained third-degree burns one hour ago, which of the following mechanisms associated with the initial inflammatory response is most likely to result in progressive tissue destruction?
(A) Downregulation of integrins
(B) Increased chemotaxis
(C) Inhibition of neutrophil degranulation
(D) Inhibition of tumor necrosis factor-alpha and interleukins 1 and 8
(E) Replacement of neutrophils with macrophages

Answer 210

(B) Increased chemotaxis

During the initial response to injury, neutrophils migrating into the wound adhere to the capillary endothelium and degranulate, resulting in the release of proteases and toxic oxygen-free radicals, leading to further tissue destruction.

Question 211

A 32-year-old man has severe pain and swelling of both hands after being exposed to hydrofluoric acid while working with a rust remover. On examination, there is significant edema, mottling, and exquisite tenderness of the index, long, and ring fingers of both hands. Digital pulses are present on Doppler ultrasonography. Following copious irrigation of the hands with water, which of the following is the most appropriate next step in management?
(A) Irrigation with 1% copper sulfate
(B) Topical application of phenol
(C) Application of a calcium sulfate splint
(D) Local injection of 10% calcium gluconate
(E) Debridement of the wounds and coverage with split-thickness skin grafts

Answer 211

(D) Local injection of 10% calcium gluconate

Following copious irrigation of the burn site with water to remove as much of the hydrogen ion as possible, 10% calcium gluconate should be injected locally in multiple small doses to prevent vascular compromise.

A topical calcium gluconate paste can be applied in patients who have less severe burns, and intra-arterial injection is advocated for patients with more severe burns.

Question 212

Copper sulfate is used for:

Answer 212

Copper sulfate is used for irrigation in patients with phosphorus burns to identify buried particles of phosphorus.

Question 213

A 2-year-old boy is brought to the emergency department after sustaining a burn to the corner of the mouth when he bit on an electric cord. The most appropriate management is splinting of the oral commissure for a minimum of what period of time?
(A) Six weeks
(B) Two to three months
(C) Six months
(D) One year

Answer 213

(C) Six months

In this child who has sustained a burn to the oral commissure, the oral commissure should be splinted for a period of at least six months. Approximately 90% of all burns of the oral commissure occur in children younger than age 4 years, and boys are twice as likely to be injured; most of these injuries occur when a child places a live electric cord into the mouth.

Question 214

In what patient population do most burns to the oral commissure occur?

Answer 214

Approximately 90% of all burns of the oral commissure occur in children younger than age 4 years, and boys are twice as likely to be injured; most of these injuries occur when a child places a live electric cord into the mouth.

Question 215

Conservative treatment after electrical injury to the oral commissure

Answer 215

Because long-term splinting has been shown to prevent microstomia and preserve function in patients who have injuries confined to the oral commissure, a custom-made device (either fixed or removable) should be applied to compress the commissure. It should be worn continuously for a minimum of six months and then at night only for several more months.

Question 216

Bleeding following electrical injury to the oral commissure

Answer 216

In these children, there is a 10% incidence of bleeding from the labial artery following injury. The child’s parent should be instructed to place the thumb and finger on the artery to control the bleeding if this does occur.

Question 217

Severe injuries following electrical injury to the oral commissure

Answer 217

In children who have more severe injuries or for whom splinting is not practical, early surgical intervention or delayed reconstruction following scar maturation is recommended. If the injury extends beyond the oral commissure, functional lip reconstruction should be performed.

Question 218

Eight months after sustaining a deep second-degree burn of the dorsal aspect of the right hand, a 45-year-old woman has hyperextension of the metacarpophalangeal joint of the little finger resulting from a progressively worsening scar contracture. Intensive occupational therapy has not improved this patient’s condition. Following release of the scar contracture, which of the following is the most appropriate operative management?
(A) Thin split-thickness skin grafting
(B) Full-thickness skin grafting
(C) Cultured epithelial autografting
(D) Coverage with a free lateral arm flap
(E) Coverage with a radial forearm flap

Answer 218

(B) Full-thickness skin grafting

This patient has a significant scar contracture after sustaining a deep second-degree burn, which by nature is defined as a partial-thickness burn. This type of burn is often associated with hyperextension scarring and preservation of the underlying extensor tendon mechanism. Following release of the scar contracture, this patient should undergo full-thickness skin grafting of the hand. The paratenon of the extensor mechanism will readily accept a full-thickness skin graft, which will maximize long-term mobility of the metacarpophalangeal joint.

Because full-thickness skin grafting will provide the best thin coverage of the burn wound, more difficult and sophisticated procedures, such as autografting or coverage with free or pedicled flaps, are unnecessary.

Question 219

Partial thickness burn over the extensors of the hand

Answer 219

This patient has a significant scar contracture after sustaining a deep second-degree burn, which by nature is defined as a partial-thickness burn. This type of burn is often associated with hyperextension scarring and preservation of the underlying extensor tendon mechanism.

Question 220

Which of the following immunologic responses is most likely to be seen in a 50-year-old woman who has sustained a 50% total body surface area (TBSA) burn in a house fire?
(A) Augmented B lymphocyte function
(B) Decreased fibronectin levels
(C) Decreased quantity of suppressor T lymphocytes
(D) Increased complement activation
(E) Increased production of IgG and IgM antibodies

Answer 220

(B) Decreased fibronectin levels

Immunologic responses anticipated in this 50-year-old woman who has sustained a 50% TBSA burn include decreased levels of fibronectin, diminished complement activation, and decreased production of immunoglobulin antibodies. Patients who sustain burn injuries enter into an immunocompromised state, in which the ability to perform the functions of phagocytosis and pathogen elimination are severely limited, resulting in an inability to produce fibronectin. In addition, there is a generalized depression of the cellular immune response, including a decrease in the quantity and function of both B and T lymphocytes; however, the number of suppressor T lymphocytes is actually increased following acute thermal injury.

Question 221

Suppressor T-lymphocytes after acute thermal injury

Answer 221

Increased

Question 222

Fibronectin after acute burn injury

Answer 222

Decreased: the ability to perform the functions of phagocytosis and pathogen elimination are severely limited, resulting in an inability to produce fibronectin.

Question 223

Patients who sustain burn injuries enter into an immuno__________ state:

Answer 223

Patients who sustain burn injuries enter into an immunocompromised state, in which the ability to perform the functions of phagocytosis and pathogen elimination are severely limited, resulting in an inability to produce fibronectin. In addition, there is a generalized depression of the cellular immune response, including a decrease in the quantity and function of both B and T lymphocytes;

Question 224

Cellular immune response after acute burn injury

Answer 224

There is a generalized depression of the cellular immune response, including a decrease in the quantity and function of both B and T lymphocytes.

Question 225

Which of the following physiologic mechanisms is increased during the first 24 hours following thermal burn injury?
(A) Cardiac output
(B) Central venous pressure
(C) Circulating erythrocyte volume
(D) Circulating glucose concentration
(E) Plasma volume

Answer 225

(D) Circulating glucose concentration

The circulating glucose concentration is increased during the first 24 hours following thermal burn injury. The affected patient develops glucose intolerance due to the release of catecholamines from the burn site. Because of this, glucose should not added to the fluids given intravenously for acute resuscitation.

Question 226

Glucose in IVF for burn resuscitation

Answer 226

The circulating glucose concentration is increased during the first 24 hours following thermal burn injury. The affected patient develops glucose intolerance due to the release of catecholamines from the burn site. Because of this, glucose should not added to the fluids given intravenously for acute resuscitation.

Question 227

Circulating levels of glucose after thermal burn injury:

Why?

Answer 227

The circulating glucose concentration is increased during the first 24 hours following thermal burn injury. The affected patient develops glucose intolerance due to the release of catecholamines from the burn site. Because of this, glucose should not added to the fluids given intravenously for acute resuscitation.

Question 228

Cardiac output after burn injury

Answer 228

Cardiac output is decreased to 40% to 60% of normal as a result of decreased plasma volume and increased systemic vascular resistance.

Question 229

Plasma volume in burn injury

Answer 229

Decreased because of capillary leak (in part)

Question 230

Circulating erythrocyte volume in acute burn injury

Answer 230

Decreased because of direct destruction of erythrocytes by the injured tissue (in part)

Question 231

In a patient who has an acute deep partial-thickness burn of the ear, which of the following is the most appropriate immediate management?
(A) Application of silver nitrate soaks
(B) Application of mafenide acetate dressings
(C) Application of silver sulfadiazine dressings
(D) Debridement of the wound and splinting
(E) Excision of the burn eschar and grafting

Answer 231

(B) Application of mafenide acetate dressings

Question 232

mafenide acetate cream is also known as

Answer 232

Sulfamylon

Question 233

Preventing suppurative chondritis after burn injury to the ear

Answer 233

In a patient who has an acute deep partial-thickness burn of the ear, the most appropriate management is application of mafenide acetate dressings every 12 hours to help prevent suppurative chondritis.

Question 234

Suppurative chondrites after burn injury to the ear

Answer 234

Topical antimicrobial therapy will prevent the development of suppurative chondritis, a painful condition that develops within the auricular cartilage in patients with this type of burn. It is first seen three to five weeks after initial injury and isextremely difficult to treat once it is acquired.

Question 235

A 25-year-old man has burn alopecia after sustaining a burn wound involving 35% of the hair-bearing scalp. Which of the following is the most appropriate method of reconstruction in this patient?
(A) Free flap reconstruction
(B) Micrografting
(C) Minigrafting
(D) Strip grafting
(E) Tissue expansion

Answer 235

(E) Tissue expansion

In patients with burn alopecia, the hair-bearing area of the scalp is amenable to tissue expansion; therefore, it is most appropriate for reconstruction in this patient. With this technique, large areas of the scalp can be resurfaced with similar tissue, resulting in reliable, consistent hair growth.

Question 236

Grafting techniques vs treatment of hair loss from burns

Answer 236

Grafting techniques, such as the use of micrografts, minigrafts, or strip grafts, are appropriate for management of male pattern alopecia but are unreliable in a patient with a compromised recipient site, such as a burn wound.

Question 237

Hair transplantation vs burn-related alopecia

Answer 237

Although hair transplantation is an option in patients with burn-related alopecia, it is not be the treatment of choice in the face of diminished vascularity and severe scarring.

Question 238

An otherwise healthy 25-year-old chef comes to the office 2 hours after sustaining scald burns when she accidentally spilled a large pot of soup. She says she washed the area immediately and dressed the burns with silver sulfadiazine. She is alert and her condition is stable. Physical examination shows partial-thickness burns on the lower abdomen, perineum, external genitalia, and anterior thighs involving approximately 15% of the total body surface area. Which of the following is the most appropriate next step in management?
A) Administration of oral antibiotics
B) Outpatient care with silver sulfadiazine
C) Parkland formula fluid resuscitation
D) Referral to the inpatient burn center
E) Split-thickness autografting

Answer 238

D) Referral to the inpatient burn center

The patient described with a partial-thickness burn greater than 10% of the total body surface area (TBSA) and a burn to the perineum meets the criteria for referral to the burn center. Other criteria for burn center referral, as advised by the American Burn Association, include burns that involve the face, hands, feet, genitalia, perineum, or major joints in both young or old patients (younger than age 5 years or older than age 60 years); third-degree burns in any age group; inhalation injury; electrical and lightning burns; chemical burns (especially hydrofluoric acid burns); and any patients with preexisting medical or social conditions that could adversely affect outcomes. Also, children admitted to a hospital without pediatric specialty care should be transferred, if possible.

Studies suggest that outcomes of complex burns improve at high-volume care centers. Most types of small burns can be managed well as outpatient cases, especially by motivated, healthy patients. Others may be eligible for home care to help with dressings if needed. High-volume fluid resuscitations, such as the Parkland formula, are employed for burns greater than 20% TBSA, as the inflammatory response mechanisms that necessitate high-volume resuscitations rarely occur with burns under 20% TBSA. Usually, oral fluids and/or modest intravenous supplementation are sufficient. Autografting should be reserved for deep or function-impeding burns that fail to respond to initial optimal burn wound care.

Question 239

A 25-year-old woman is brought to the emergency department after sustaining deep partial-thickness and full-thickness burns to the face, neck, chest, back, and bilateral upper extremities in a grease fire. The patient is intubated and resuscitated, and the wounds are managed surgically. Which of the following is the most appropriate position to splint the burned areas?
A) Elbow extended at 180 degrees
B) Hands in intrinsic minus position
C) Neck flexed at 45 degrees
D) Shoulder abducted at 60 degrees
E) Wrist flexed at 10 degrees

Answer 239

A) Elbow extended at 180 degrees

The most appropriate position to splint the different burned areas is neck in slight extension, shoulder fully abducted to about 90 degrees, elbow fully extended at 180 degrees, wrist in neutral or slightly extended, and hands in intrinsic plus position or position of function. This is done to prevent contractures that would pull these joints into positions that would lead to functional deficits.

Question 240

A 27-year-old man is brought to the regional burn center 4 hours after he got lost in a snowstorm while he was hiking. Physical examination shows severe frostbite of the feet, purple coloring of the toes, heavy blistering, and marked edema. On Doppler examination, pulses are absent bilaterally. He sustained no other injuries and is otherwise healthy. In addition to warming and pain control, which of the following is the most appropriate next step in the treatment of this patient?
A) Angiography
B) Fasciotomy
C) Hyperbaric oxygen therapy
D) Intravenous administration of heparin
E) Technetium-99 triple-phase scanning

Answer 240

A) Angiography

Frostbite is a common injury to the homeless and outdoor adventurers. Direct injury is caused by extracellular freezing of tissues with significant changes of the osmotic gradient of cells which can cause significant electrolyte imbalances. Many inflammatory mediators, including thromboxanes, prostaglandins, histamine, and bradykinin are released which lead to significant edema, endothelial injury, and tissue damage.

The mainstay of frostbite injuries, regardless of severity, includes rewarming, pain control, administration of tetanus prophylaxis, and frequent dressing changes and wound care. In cases of severe frostbite injuries with absent pulses, emergent angiography and infusion of tissue plasminogen activator (tPA) have been shown to significantly decrease the rate of amputation if administered within 24 hours of the onset of frostbite.

Although fasciotomy might be necessary after reperfusion, it is not indicated as a first-line therapy for frostbite. Likewise, heparin and hyperbaric oxygen have not been shown to improve the outcomes in frostbite injuries.

Technetium-99 triple-phase scanning can accurately estimate the level of eventual amputation required if performed in the first several days, but it is not a therapeutic modality and would delay the angiography and administration of tPA if indicated.

Question 241

A 165-lb (75-kg), 40-year-old man is brought to the emergency department 3 hours after sustaining first-degree burns to the hands and second- and third-degree burns to the entire anterior thorax and both anterior and posterior lower extremities. According to the Parkland formula, administration of which of the following is the most appropriate method of initial fluid resuscitation in this patient?
A) Hypertonic saline solution 253 mL/hr for 5 hours
B) Hypertonic saline solution 1181 mL/hr for 8 hours
C) Ringer’s lactate 506 mL/hr for 24 hours
D) Ringer’s lactate 1013 mL/hr for 8 hours
E) Ringer’s lactate 1620 mL/hr for 5 hours

Answer 241

E) Ringer’s lactate 1620 mL/hr for 5 hours

Massive injury and burns result in a systemic inflammatory response with resultant leakage of fluid into the interstitial space. Large fluid shifts can decrease perfusion to vital organs and inadequate resuscitation will result in acidosis, oliguria, and relative polycythemia. Fluid replacement is based on the observation that intravascular fluid loss into the interstitium is relatively constant during the first post-injury day. All fluid, therefore, is administered at a constant rate to avoid excessive interstitial edema. Patients are monitored for an adequate clinical response by measurement of hourly urine output (0.5–1 mL/kg/hr for adults) with adjustments as needed. Invasive monitoring may be necessary in elderly patients, patients with cardiac dysfunction, or patients with severe pulmonary injury.

A variety of fluid resuscitation formulas are available to guide the initial management of fluid replacement. The Parkland formula and its variations have become the standard methods for resuscitation. Isotonic crystalloid, Ringer’s lactate in particular (sodium concentration of 130 mEq/L) is the fluid of choice. The Parkland formula directs the resuscitation as follows: 4 mL of fluid × patient weight in kilograms × total body surface area (TBSA) percentage of second- and third-degree burns. Half of this total volume is delivered in the first 8 hours and the second half over the ensuing 16 hours. In a delayed presentation (3 hours in this clinical example), half of the total volume must be delivered within the 8-hour window (remaining 5 hours in this example).

The TBSA is calculated using the “Rule of Nines,” as follows:

Head/Neck = 9%
Each upper extremity = 9%
Anterior thorax = 18%
Posterior thorax = 18%
Each lower extremity = 18%
Groin = 1%
In this patient example, the TBSA of burn is 54%: Anterior thorax (18%) + each lower extremity (18% + 18%). The Parkland formula considers only second- and third-degree burns for calculation of resuscitation volume; therefore, the first-degree burns in this case are ignored.

In this clinical example, 4 mL × 75 kg × 54% TBSA = 16,200 mL total fluid over 24 hours. The patient will require 8100 mL in the first 8 hours and 8100 mL over the ensuing 16 hours. Because the patient presented 3 hours post burn, he will require 8100 mL over the next 5 hours which gives an hourly rate of 1620 mL/hr.

Question 242

An otherwise healthy 35-year-old man is exposed to subzero temperatures for 24 hours. After initial management of hypothermia and rapid rewarming of the hands, bilateral upper extremity frostbite is evaluated. Physical examination shows severe frostbite of the hands and up to the wrists bilaterally. Which of the following is the most appropriate next step in management?
A) Corticosteroid therapy
B) Heparin therapy
C) Surgical debridement
D) Systemic antibiotic therapy
E) Thrombolytic therapy

Answer 242

E) Thrombolytic therapy

The most appropriate next step in management is to consider intra-arterial thrombolytic therapy. The treatment of frostbite has remained essentially unchanged for the past 25 years. Classic management of frostbite injury includes resuscitation, rewarming, and watchful waiting. The outcome is either tissue recovery or progressive gangrene leading to eventual amputation. A variety of maneuvers aimed at advancing the care of patients with frostbite have been attempted, including hyperbaric oxygen, surgical and medical sympathectomy, pharmaceutical agents, and anticoagulation. None of these have resulted in alterations in the management of this disorder. Recent reports have described the use of thrombolytic therapy using urokinase or tissue plasminogen activator (tPA) as a potential therapy for frostbite.

The rationale for this therapy is based on the understanding that tissue injury in frostbite occurs from two distinct components. Initially, tissue freezing and crystal formation occur and then are improved with tissue rewarming. The more significant cause of tissue injury occurs after thawing, and it is the robust local tissue inflammation and coagulation that stimulate microvascular thrombosis and progressive cell death. By reversing local microvascular thrombosis, tPA has been postulated to restore perfusion before irreversible ischemia and necrosis.

Systemic corticosteroids or antibiotics are not indicated at this time. Systemic heparinization is usually employed as an adjunct after intra-arterial thrombolytics have been initiated. However, it is delivered intravenously. Surgical debridement is done in a delayed fashion after the area of frostbite has demarcated, sometimes weeks to months later.

Question 243

A 35-year-old man is admitted to the burn unit after sustaining superficial partial-thickness burns involving 25% of the total body surface area. Medical history includes an allergy to sulfonamide. The burns are cleaned, and silver nitrate–soaked dressings are applied. Which of the following is most likely in this patient?
A) Hyponatremia
B) Metabolic acidosis
C) Neutropenia
D) Painful application
E) Thrombocytopenia

Answer 243

A) Hyponatremia

Because of the skin’s important function as a microbial barrier, prevention of infection after burn injury is still one of the most difficult challenges in caring for burn patients. The development of effective topical antimicrobial agents has markedly reduced the incidence of invasive burn wound infection and sepsis. Topical therapy should be started after the initial wound debridement. The three most common topical antimicrobial agents are silver sulfadiazine (Silvadene), silver nitrate, and mafenide acetate (Sulfamylon).

Silver nitrate is typically delivered as a 0.5% solution as a wet dressing. Silver nitrate has excellent antibacterial properties and is effective for most Staphylococcus species and most gram-negative aerobes, including Pseudomonas. This agent is typically used when there is a history of sulfonamide allergy or when sensitivity to the other agents has developed. A common use of silver nitrate is in the setting of toxic epidermal necrolysis. Application is painless, but tissue penetration is poor. Concentrations above 5% are cytotoxic to healthy tissues. Because leaching of sodium, potassium, and calcium is common, this effect should be anticipated and replaced appropriately.

Painful application is associated with mafenide acetate (Sulfamylon). Mafenide acetate is delivered as suspension in a water-soluble base. As a result of its solubility, it has excellent tissue penetration and is often used in heavily contaminated wounds with thick eschar. Because of excellent cartilage penetration, it is also the agent of choice with ear burns. Mafenide acetate is highly effective against gram-negative organisms. Adverse effects include hypersensitivity reactions (7% of patients) and inhibition of carbonic anhydrase with a resultant hyperchloremic metabolic acidosis.

Silver sulfadiazine is the most common topical antimicrobial agent used. It has intermediate tissue penetration secondary to its limited water solubility. This agent has a good antibacterial spectrum, a low incidence of development of resistant organisms, and is applied painlessly. Transient leukopenia is a common adverse effect of silver sulfadiazine. This condition is self-limited and does not appear to increase mortality in burn patients. Switching to a different topical agent for a few days will allow the white blood cell count to return to normal.

Thrombocytopenia is not associated with silver nitrate.

Question 244

An 18-year-old woman who sustained a flame burn involving 50% of the total body surface area is resuscitated to a stable cardiovascular and respiratory status. Four days after injury, she undergoes tangential excision and xenografting of all burned areas. Following surgery, the patient returns to the ICU intubated and ventilated. She has thick pulmonary secretions. She received 2 units of packed red blood cells during surgery. Vital signs are as follows:
Temperature 99.5°F (37.5°C)
Heart Rate 130 bpm
Respiratory Rate 22/min
Blood Pressure 80/50 mmHg
Oxygen saturation is 96% on 40% FIo2. Cardiac output is 6 L/min, and urine output is 0.1 mL/kg/h. Which of the following is the most likely explanation for these abnormal findings?

A) Acute respiratory distress syndrome
B) Hypovolemic shock
C) Pneumonia
D) Pulmonary embolism
E) Sepsis

Answer 244

B) Hypovolemic shock

The most likely explanation for this patient’s abnormal physiology is hypovolemic shock. The patient just underwent tangential excision of a 50% total body surface area burn, and marked blood loss is to be expected. She received 2 units of packed red blood cells, but this is unlikely to be adequate for such a large burn excision. In addition, her vital signs are typical for hypovolemic shock. Sepsis and acute respiratory distress syndrome (ARDS) are often seen in patients with large burns, but they are usually seen later in the hospital course. Sepsis is associated with fever and a high cardiac output. ARDS is associated with previous large-volume transfusions and lung injury, and should not cause hypotension in isolation. It is also associated with more severe hypoxia. Pneumonia and pulmonary embolism are also associated with a more profound hypoxia than this patient exhibits and are usually seen later in a burn patient’s hospital course.

Question 245

An otherwise healthy 35-year-old woman is brought to the burn unit because of severe scalding injury to 50% of the total body surface area. Physical examination shows circumferential full-thickness burns to the right upper extremity, and absent distal pulses. Capillary refill time in the fingers is more than 3 seconds. Appropriate airway control and fluid resuscitation are initiated. Emergent right upper extremity escharotomies are performed. Despite surgical intervention, the blood flow to the distal extremity remains poor based on capillary refill time and Doppler flows. Which of the following is the most appropriate next step in management?
A) Additional escharotomies
B) Administration of an intravenous fluid bolus
C) Angiography
D) Elevation of the extremity and reexamination in 45 minutes
E) Fasciotomy of the upper extremity

Answer 245

E) Fasciotomy of the upper extremity

The most appropriate next step in management is to proceed with urgent fasciotomies of the upper extremity. Indications for emergency extremity escharotomy are the presence of a circumferential eschar with impending or established vascular compromise of the extremities or digits. Progressive flow reduction by Doppler ultrasound is the primary indication for escharotomy. When evaluating upper extremities, it is advised to Doppler ultrasound the palmar arch, not the wrist, so as to evaluate distal blood flow. Other indications include decreased capillary refill time (more than 2 seconds), cyanosis, and/or relentless deep pain progressing to numbness (in awake patients). Neurovascular integrity should be monitored frequently and in a scheduled manner. Capillary refill time, Doppler signals, pulse oximetry, and sensation distal to the burned area should be checked hourly. After the escharotomy, any continued increase in capillary refill time, decrease in Doppler signal, or change in sensation should lead to immediate further decompression via fasciotomy. A carpal tunnel release is vital during the fasciotomy.

Escharotomies typically are performed at bedside under sterile conditions with intravenous sedation using electrocautery. The aim is to make surgical incisions through burned eschar to allow expansion of underlying tissues. In extremity escharotomies, full-thickness incisions along medial and lateral mid-axial lines should be made. Escharotomies should be carried to just beyond the area of the full-thickness burn. Digital escharotomies are performed along the mid-axial line between neurovascular bundle and extensor apparatus. The ideal side to perform escharotomy allows for preservation of pinch: thumb requires radial incision only, and the index finger, long finger, ring finger, and little finger require ulnar incisions only.

In the scenario described, further fluid boluses, escharotomies beyond the standard releases, and management would not be appropriate next steps, and would increase the risk of local complications like further ischemia, tissue necrosis/gangrene, or systemic complications like hyperkalemia, metabolic acidosis, and renal failure.

Question 246

A 27-year-old man is brought to the emergency department after sustaining second- and third-degree burns to most of the anterior torso and the upper extremities. Which of the following describes the appropriate amount of Ringer’s lactate, according to the Parkland formula, for fluid management of this patient’s condition?
A) 1 mL/% TBSA/kg given over the first 6 hours
B) 2 mL/% TBSA/kg given over the first 8 hours
C) 2 mL/% TBSA/kg, half given over the first 8 hours
D) 4 mL/% TBSA/kg given over the first 6 hours
E) 4 mL/% TBSA/kg given over the first 8 hours

Answer 246

B) 2 mL/% TBSA/kg given over the first 8 hours

The amount of Ringer’s lactate (mL) needed for initial resuscitation is formulated by the Parkland formula of 4 mL/kg/% the total body surface area (TBSA) burned, with half this volume infused over the first 8 hours from the time of injury. In other words, for the first 8 hours, the patient should receive 2 mL/% TBSA/kg. All other options are not accurate based on the Parkland formula and this patient’s TBSA.

One easy way to determine the hourly rate for the first 8 hours is to multiply the % TBSA and kg, and divide by 4. Because the Parkland formula is 4 mL/% TBSA/kg, with half given over the first 8 hours, the 4 in the Parkland formula can be divided by 16 (2 × 8) to give a denominator of 4.

It is absolutely critical to perform accurate estimation of the burn size and weight, because overzealous fluid administration can lead to fluid creep, compartment syndromes, and pulmonary complications.

Question 247

A 26-year-old lineman is brought to emergency department after accidentally grabbing a high-voltage power line. The most severe injury is seen at which of the following anatomical locations?
A) Chest wall
B) Neck
C) Shoulder
D) Upper arm
E) Wrist

Answer 247

E) Wrist

Severity of injury is proportional to the cross-sectional area of tissue able to carry current. Thus, the most severe injuries are seen at the wrists and ankles, with decreasing severity proximally. The extremities are the most frequently injured body parts, with the upper extremity predominating.

Most high-voltage injuries occur in workers on the job, so the voltage is known. Temperature increase parallels changes in amperage with tissue temperature being a critical factor in the magnitude of tissue damage. Tissue resistance from lowest to highest is nerve, blood vessels, muscle, skin, tendon, fat, and bone. Deep tissue seems to retain heat so that periosseous tissues, especially between two bones, often sustain a more severe injury than more superficial tissue. The associated macro- and microscopic vascular injury seems to occur nearly immediately and is not reversible. Alternating current (AC) causes tetanic muscle contraction, which may either throw victims away from contact or draw them into continued contact with the electrical source, the latter being more common, given our propensity to grasp at objects and the greater strength in our forearm flexors relative to extensors. This effect is often described as the “no-let-go” phenomenon. Altered levels of consciousness are reported in about half of high-voltage injuries. The tissue injury in electrical burns seems to be a combination of thermal and nonthermal mechanisms. If enough heat is generated, the tissue heats to supraphysiologic temperatures causing denaturation of macromolecules, which is usually irreversible. Electroporation refers to the formation of aqueous pores in lipid bilayers exposed to a supraphysiologic electric field. The applied electric field alters the transmembrane potential, with muscle fibers and nerves being the most susceptible. Subsequent pore formation likely allows calcium influx into the cytoplasm, thereby triggering apoptosis and cell death. Electroporation can therefore induce cell necrosis in the absence of heating.

Transmembrane protein molecules contain polar amino acid residues that can change orientation in an electric field. This effect, known as electroconformational protein degradation, may be irreversible and form yet another mechanism of nonthermal injury.

Question 248

An otherwise healthy 22-year-old man is brought to the emergency department after sustaining full-thickness skin loss to the hands. Two-stage reconstruction is planned using a bilaminate neodermis (Integra), followed by skin grafting and simple gauze dressings. Which of the following is the average time for maturation (time from application to removal of silicone layer) of Integra with simple gauze dressings only?

A) 1 week
B) 3 weeks
C) 6 weeks
D) 9 weeks
E) 12 weeks

Answer 248

B) 3 weeks

Integra is a bilaminar skin substitute, composed of a silicone outer layer (mimicking the epidermis) and a biologic scaffold for the inner, dermal layer. Typical maturation (time from application to removal of silicone layer) is 21 days. This process can be accelerated with the use of negative-pressure dressings, but that is not described in this scenario.

Question 249

A 72-year-old man with advanced congestive heart failure who recently received a left ventricular assist device (LVAD) comes to the office with an ulcerated mass in the mid-parietal region. Punch biopsies reveal squamous cell carcinoma of the skin. The patient has a history of bilateral temporal and midline craniotomies for resection of symptomatic meningiomas. Wide local excision of the tumor creates a scalp defect measuring 8 cm in diameter, with calvarial bone denuded of periosteum at its base. Which of the following is most appropriate for coverage of this patient’s defect?
A) Dermal regeneration template, followed by skin autograft
B) Fasciocutaneous free tissue transfer
C) Full-thickness skin autograft
D) Interpolated scalp flaps, with skin autograft to cover the secondary defect
E) Pericranial flap, covered with skin autograft

Answer 249

A) Dermal regeneration template, followed by skin autograft

The most appropriate coverage of the oncologic defect in this patient is with a dermal regeneration template, such as Integra, followed by skin autograft.

Integra is a synthetic bilaminate neodermis composed of a collagen lattice covered with a thin silastic sheet. A single-layer version (collagen only) is also available, allowing stacking of the product for increased soft-tissue thickness. Vascularization of the collagen layer usually occurs in 3 to 4 weeks, at which point the silastic sheet is removed and a thin split-thickness skin autograft is applied. In the absence of pericranium, burring of the exposed calvarium down to healthy bleeding bone is recommended.

A skin autograft applied directly to calvarial bone denuded of periosteal coverage is unlikely to “take.” Interpolated scalp flaps, most likely requiring grafting of a secondary defect (donor site), would be appropriately indicated for coverage of a midparietal 8-cm defect. These are large flaps, based on the major blood vessels supplying the scalp, with an area of undermining that frequently involves the entire scalp. Unfortunately for this patient with multiple previous craniotomies, the resulting scars impose an unacceptably high risk for flap ischemia.

Similarly, a scar-free, well-vascularized pericranial flap large enough to cover the described defect is unlikely to be found in this patient. The safety and success of free tissue transfer in patients depending on LVADs for hemodynamic stability is still to be determined.