Inservice Exam - 2005
Burns

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

The correct response is Option C.

The major burn criteria of the American Burn Association identify individuals, such as those with diabetes mellitus, who need specialized treatment because they are at high risk for postburn morbidity and mortality. The criteria for triage to a specialized burn center include:

$ second- or third-degree burn over more than 10% of the total body surface area (BSA) in a patient younger than 10 years or older than 50 years
$ second- or third-degree burn over more than 20% of the total BSA in a patient of any other age
$ significant burn of the face, hands, feet, genitalia, perineum, or skin over major joints
$ third-degree burn over more than 5% of the total BSA in a patient of any age
$ burn with concomitant inhalation injury, significant electrical injury including lightning strike, or significant chemical injury
$ burn with a significant preexisting medical disorder that complicates management, such as diabetes mellitus or heart disease
$ burn with concomitant trauma
$ burn in a patient who might have special social or emotional needs or require long-term support, as in a child who has been abused or neglected

References:
1. Minanov OP, Peterson P. Burn injury. In: Georgiade GS, Riefkohl R, Levin LS, eds. Georgiade Plastic, Maxillofacial, and Reconstructive Surgery. 3rd ed. Baltimore: Williams & Wilkins; 1997:198.
2. Pruitt B, Goodwin C, Mason A. Epidemiological, demographic and outcome characteristics of burn injury. In: Herndon D, ed. Total Burn Care. 2nd ed. Philadelphia: WB Saunders; 2001.



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)


The correct response is Option D.


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.

Scar release and coverage with a thin split-thickness skin graft have an unacceptable rate of recurrence of contracture. Scar release and coverage with a free scapular flap or dorsal scapular island flap are ideal options for reconstruction. However, unburned scapular skin is not likely to be available in a patient with burns over 90% of the total body surface area.

References:
1. Frame JD, Still J, Lakhel-LeCoadou A, et al. Use of dermal regeneration template in contracture release procedures: a multicenter evaluation. Plast Reconstr Surg. 2004;113(5):1330-1338.
2. Angrigiani C, Grilli D, Karanas YL, et al. The dorsal scapular island flap: an alternative for head, neck, and chest reconstruction. Plast Reconstr Surg. 2003;111(1):67-78.



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


The correct response is Option B.


Silver sulfadiazine (Silvadene) is a commonly used topical burn agent. It may result in granulocyte reduction (neutropenia and thrombocytopenia). Carbonic anhydrase inhibition may occur with mafenide acetate (Sulfamylon), resulting in metabolic acidosis. 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.



References:
1. Heggers J, Hawkins H, Edgar P, et al. Treatment of infections in burns. In: Herndon D, ed. Total Burn Care. 2nd ed. Philadelphia: WB Saunders; 2001.
2. Moncrief JA, Lindberg RB, Switzer WE, et al. The use of a topical sulfonamide in the control of burn wound sepsis. J Trauma. 1966;6(3):407-414.




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

The correct response is Option A.

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.

References:
1. Baxer CR. Fluid volume and electrolyte changes in early postburn period. Clin Plast Surg. 1974;1:693.
2. Kao CC, Garner WL. Acute burns. Plast Reconstr Surg. 2000;105(7):2482-2492.




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
The correct response is Option D.


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 evident.


Before postoperative day 21, revascularization is not adequate. In fact, the Moiemen, Staiano, and Ojeh study found that full revascularization was more likely to occur at four weeks.


References:
1. Moiemen NS, Staiano JJ, Ojeh NO, et al. Reconstructive surgery with a dermal regeneration template: clinical and histologic study. Plast Reconstr Surg. 2001;108(1):93-103.
2. Dantzer E, Braye FM. Reconstructive surgery using an artificial dermis (Integra): results with 39 grafts. Br J Plast Surg. 2001;54(8):659-664.




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


The correct response is Option C.


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.


If a bacterial infection occurs, it usually begins more than two days after the injury. Examination of the eyes with a light is unlikely to cause further damage. Scar tissue is unlikely to develop within two days.


References:
1. Sanford AP, Herndon DN. Chemical burns. In: Herndon D, ed. Total Burn Care. 2nd ed. Philadelphia: WB Saunders; 2001:475-480.
2. Wright KW. Ocular trauma. In: Wright KW, ed. Textbook of Ophthalmology. Baltimore: Williams & Wilkins; 1997:889-897.





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


The correct response is Option E.


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. If these findings are present, 100% oxygen should be administered immediately using a non-rebreather mask. Because pulse oximetry cannot differentiate between oxyhemoglobin and carboxyhemoglobin, artificially high readings are often obtained even in patients with carbon monoxide toxicity. 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.


Any patient who has a carbon monoxide level of 30% or higher on arrival in the emergency department, even after receiving supplemental oxygen, has suffered severe toxicity. 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.


Hyperbaric oxygen may be administered to patients with severe carbon monoxide poisoning, but, in emergency cases, this time-consuming process is not advocated.


Bronchoscopy or ventilation scanning should be performed to confirm smoke inhalation, but is less urgent than management of the airway in this patient.


Cricothyroidotomy is indicated only in patients with severe swelling of the airway when intubation is not possible.


Chest escharotomy is indicated in patients with respiratory compromise and circumferential chest burns, but should not be performed before breathing has improved.


References:
1. Kao CC, Garner WL. Acute burns. Plast Reconst Surg. 2000;105:2482-2492.
2. Yowler CJ, Fratianne RB. Current status of burn resuscitation. Clin Plast Surg. 2000;27:1-10.




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

The correct response is Option B.

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. Local and systemic inflammatory mediators may play a role in these processes.

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. Paralytic ileus is a systemic result of a major burn but is not a factor in the initial development of shock. Renal shutdown is an effect of initial shock, not a factor in its development, but can occur from sustained hypovolemia.

References:
1. Kramer GC, Lund T, Herndon DN. Pathophysiology of burn shock and burn edema. In: Herndon D, ed. Total Burn Care. 2nd ed. Philadelphia: WB Saunders; 2001:78-87.
2. Press B. Thermal, electrical and chemical injuries. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 1997:161-190.




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

The correct response is Option D.


In a patient who has a second- and/or third-degree burn injury that covers more than 20% of the total body surface area (TBSA), acute fluid resuscitation should be performed with administration of lactated Ringer’s solution during the initial 24 hours after injury. The Parkland formula is used to estimate the amount of fluid required. According to this formula, lactated Ringer’s solution (4 mL/kg/% TBSA burned) should be administered during the first 24 hours. A total of 50% of the solution should be administered during the first eight-hour period and the remaining 50% over the next 16 hours.


The TBSA involved in a burn can be calculated using the “rule of nines.” According to this rule, the anterior trunk, the posterior trunk, and each lower extremity are assigned values of 18%. Each upper extremity and the head have values of 9%, and the neck has a value of 1%. 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.

References:
1. Salisbury RE. Thermal burns. In: McCarthy JG, May JW, Littler JW, eds. Plastic Surgery. Vol 1. Philadelphia: WB Saunders; 1990:791-795.
2. Warden GD. Fluid resuscitation and early management. In: Herndon D, ed. Total Burn Care. 2nd ed. Philadelphia: WB Saunders; 2001:90-91.




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


The correct response is Option D.
Because frostbite injuries can cause devastating loss of tissue, aggressive management is often needed to salvage and provide vascularized coverage over viable bone. 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 distal interphalangeal joints and primary closure would leave the middle phalanx nonvascularized. Amputating at the MP joint would sacrifice viable bone. Amputation at the level of the MP joints and radial forearm flap reconstruction would sacrifice viable bone, and the radial forearm flap would not be needed for coverage. 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.

References:
1. Leonard LG, Daane SP, Sellers DS, et al. Salvage of avascular bone from frostbite with free tissue transfer. Ann Plast Surg. 2001;46(4):431-433.
2. Greenwald D, Cooper B, Gottlieb L. An algorithm for early aggressive treatment of frostbite with limb salvage directed by triple-phase scanning. Plast Reconstr Surg. 1998;102(4):1069-1074.