Burn

A 58-year-old woman develops full-thickness dermal necrosis in a 4 × 4 × 2-cm area of her lower breast following reduction mammaplasty. After debridement to healthy tissue, she starts daily wound packing with a calcium alginate fiber dressing. The main advantage of calcium alginate versus saline gauze dressings is a decrease in which of the following? A) Dressing change frequency B) Healing time C) Keloid scarring D) Treatment cost E) Wound infection rate

A An effective dressing should aid in surface debridement, absorb wound exudate, and maintain a moist healing environment. Normal saline wet-to-dry gauze dressings have been a mainstay of wound management for generations because they are easy to perform, widely available, and inexpensive. They are best changed 2 to 3 times daily to remove exudative material because they can quickly become saturated. Some of the wound healing byproducts, such as metalloproteinases and elastase, can slow down wound healing and result in chronic wounds. By wicking away these potentially harmful agents, more absorptive wound dressings can help simplify care. Alternatives to conventional saline wet-to-dry gauze dressing materials include hydrogels, hydrocolloids, foams, alginates, and negative pressure dressings. They are more expensive than traditional saline-gauze dressings but are typically far more absorptive, allowing for less frequent dressing changes. Daily dressing changes versus two to three times a day are far more convenient for patients and may ultimately save total treatment costs by allowing for fewer nursing visits or allowing for outpatient care. Many studies show no difference in healing times, though some studies suggest a mild benefit in diabetic foot ulcers. Current recommendations call for additional studies, as evidence of faster healing times is lacking. No studies show lower infection or scarring. Calcium alginates are fibers made of brown seaweed fibers, and they can hold more than ten times their weight in fluid. Some manufacturers claim that they are able to deactivate metalloproteinases and stimulate healing, although in vitro data are lacking. They are a comfortable and effective alternative to saline wet-to-dry dressings, albeit at a higher product cost.

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

A 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.

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

A 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.

A 25-year-old right-hand-dominant woman sustains a full-thickness circumferential burn to the right upper extremity from the shoulder to the wrist. She undergoes early excision and grafting. Six months after treatment, she undergoes operative release of a severe flexion contracture of the elbow (greater than 50% loss of joint motion), resulting in a large defect. Which of the following is the most appropriate option for reconstruction of the defect? A) Free fasciocutaneous flap B) Full-thickness skin grafting C) Local perforator flap D) Split-thickness skin grafting E) Z-plasty

A In severe burn scar contractures, adjacent tissue transfer (Z-plasty, VY-plasty) and skin grafts are not indicated. Perforator-based local flaps have low recurrence rates but one limitation of this technique is the availability of local normal skin. In this specific case, no normal skin is available. Free tissue transfer is the best option. Perforator vessels are normally protected and can serve as recipient vessels for the free flap transfer.

A 45-year-old African American woman who underwent cardiac surgery 6 months ago seeks cosmesis of the surgical scar. Physical examination shows a raised, thick keloid scar that is pruritic. Which of the following nonsurgical treatments is likely to produce the most rapid improvement in the scar with the fewest adverse effects? A) Intralesional 5-fluorouracil B) Intralesional triamcinolone C) Radiation therapy D) Silicone sheeting E) Topical triamcinolone

A Injection of 5-fluorouracil demonstrates similar efficacy to intralesional corticosteroid therapy (triamcinolone) and has the advantage of a lower risk of hypopigmentation. Silicone sheeting is effective for hypertrophic scars but requires serial application and is slower in visible effect. Topical corticosteroids are not as effective as intralesional treatment. Radiation carries the risk of adjacent tissue toxicity and also includes the risk of skin pigmentation changes.

A 50-year-old man with a history of organ transplantation is scheduled to undergo resection of a squamous cell carcinoma of the scalp followed by reconstruction with a flap. This patient is most likely to avoid postoperative wound-healing complications if he is currently undergoing which of the following immunosuppressive therapies? A ) Antilymphocyte antibody (basiliximab) B ) Antimetabolite (azathioprine) C ) Calcineurin inhibitor (cyclosporine) D ) Glucocorticosteroid (prednisone)

A Many immunosuppressive agents used in organ transplantation have been shown to impair wound healing. Thus, free tissue transfer or major reconstructive surgery has been associated with higher complication rates. Immunosuppressive agents can be categorized as antilymphocytes (lymphocyte immune globulin [Atgam], thymoglobulin, basiliximab), antimetabolites (azathioprine, mycophenolate mofetil), calcineurin inhibitors (cyclosporine, FK-506), and glucocorticosteroids. Only antilymphocyte therapy has been shown not to impair wound repair.

An otherwise healthy 25-year-old woman is scheduled to undergo resection of a 3 × 5-cm atypical nevus of the right thigh. Medical history includes systemic lupus erythematosus. She has been receiving oral corticosteroid therapy for more than 5 years. She is well nourished. Perioperatively, administration of which of the following vitamins is most likely to improve this patient's wound healing? A) A B) B complex C) C D) D E) E

A Perioperative administration of vitamin A is most likely to improve wound healing in this well-nourished patient receiving chronic corticosteroid therapy. Corticosteroids have been shown to negatively affect all major steps of the wound healing process. Several mechanisms have been proposed, including a stabilizing effect in the lysosomal membrane of cells. Vitamin A was known to cause the opposite (destabilizing) effect in lysosomal membranes in vivo, which led to the first studies on the interaction between these two classes of drugs in wound healing in the 1960s. Since then, supplementation of vitamin A in patients receiving corticosteroids has been shown to counteract most of the deleterious effects of corticosteroids in wound healing, with the exception of wound contraction and infection. There is no consensus in dose and duration of treatment. Most proposed regimens include oral administration of 10,000 to 25,000 international units (IU) per day for 5 to 14 days. Various topical regimens have also been proposed, with doses around 200,000 IU every 8 hours. Administration of vitamins B, C, D, or E has not been shown to significantly improve wound healing in well-nourished patients. Vitamin C deficiency impairs collagen synthesis, which may lead to poor wound healing and scurvy.

An 87-year-old woman with a history of squamous cell carcinoma on the left lower extremity comes for evaluation because of the ulcer shown in the photograph. When the tumor did not resolve 9 months ago, she underwent radiation therapy for 4 weeks followed by excision. All margins were negative. Coverage of the wound with a split-thickness skin graft 6 months ago was not successful. Physical examination shows an ulcerated area over the anterior compartment. There is moderate fibrinous debris within the ulcer. Which of the following is the most likely underlying cause of the impeded wound healing? A) Decreased vascularity B) Elevated oxygen tension C) Enhanced angiogenesis D) Fibroblast hyperplasia E) Peripheral margin hypokeratosis

A Radiation therapy produces many changes in the skin, whether it is directed at the skin, such as for skin cancer, or directed at deeper structures. Direct damage to blood vessels in the wound bed (obliterative endarteritis) produces decreased oxygen tension. Unlike nonirradiated wounds, radiated wounds do not respond with increased angiogenesis. Decreased breaking strength of radiated wounds is caused by both edema of collagen bundles and direct injury to the fibroblasts that would otherwise repair them. Radiated wounds have hyperkeratotic edges, which impair both contraction and keratinocyte migration.

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

A 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.

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

A 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.

A 33-year-old African American woman has a large recurrent keloid of the left earlobe. Reexcision with postoperative radiation therapy is planned. Which of the following is the most likely long-term complication of this therapeutic plan? A) Altered pigmentation B) Desquamation C) Itching D) Skin cancer E) Telangiectasia

A The patient described has a recurrent keloid after previous excision. Surgery alone has recurrence rates of over 50%, and combination therapies including injection of a corticosteroid, pressure earrings, and surgery can have marked recurrence rates. For recurrent keloids, post-excision radiation therapy, usually given in one to three fractions, has efficacy rates between 6 and 98%. The most common long-term complications of radiation therapy include hypo- or hyperpigmentation (62%) and telangiectasias (27%). Skin desquamation is an acute reaction to radiation therapy and occurs in 24% of patients. Secondary malignancies after radiation therapy for keloids are very rare. Itching from keloids is usually improved with treatment.

A 10-year-old boy underwent removal of a pigmented nevus from his scalp 2 weeks ago with suture closure. The tensile strength of the incision line today is most likely which of the following percentages of its final strength? A) 10% B) 20% C) 40% D) 60% E) 80%

A The tensile strength of a skin incision 2 weeks following repair is approximately 10%. Classic studies by Madden and Peacock showed that a cutaneous wound achieves 5% of its ultimate strength after 1 week, 10% after 2 weeks, 20% after 3 weeks, 40% after 4 weeks, and 80% after 6 weeks. The scar has its full strength 12 weeks after repair.

A morbidly obese woman is brought to the emergency department after being found unconscious at home. Her family reports that both of the patient's arms were pinned beneath her body when emergency medical service responders arrived. Physical examination shows tense swelling of the upper extremities. The now conscious patient reports severe pain to passive extension of the digits. In addition to appropriate urgent operative management, the surgeon should anticipate which of the following? A) Decreased glomerular filtration rate B) Hypercalcemia C) Hyperglycemia D) Hypokalemia E) ST-segment elevation

A This patient has bilateral upper extremity compartment syndrome. The emergency department examination of concern for a long-standing period of upper extremity ischemia. The surgeon should anticipate rhabdomyolysis and its consequent renal and metabolic disorders. Supportive treatment should be undertaken. Hyperkalemia is common in rhabdomyolysis manifesting as peaked T waves on ECG as serum potassium concentrations rise. Glucose D50W, 50 mL intravenously, plus regular insulin (5 to 10 units) move potassium from the extracellular fluid to the intracellular fluid. Intravenous mannitol increases renal blood flow (GFR), attracts fluid from the interstitium (thereby counterbalancing hypovolemia), increases urinary flow (prevents myoglobin cast obstruction), and functions as a free radical scavenger. Allopurinol may be helpful in reducing the production of uric acid. It also acts as a free radical scavenger. Hypocalcemia is commonplace in the initial phase of rhabdomyolysis; however, it does not usually require correction because this would increase the risk of intramuscular calcium deposition. Indication for correcting hypocalcemia would be impending seizures.

A 66-year-old, 132-lb (60-kg) woman presents to the emergency department with a deep second-degree, 20% total body surface area burn, with a small area of surrounding first-degree burn. This happened in an open space when she fell backwards onto a fire pit. Her burns are isolated to her buttock and back. She reports no hoarseness or difficulty breathing. She receives 9600 mL of Ringer's lactate within the first 24 hours. Based on her fluid resuscitation, she is at highest risk for which of the following? A) Abdominal compartment syndrome B) Conversion of the burn to full-thickness C) Deep venous thrombosis D) Digit ischemia E) Poor engraftment of autologous skin grafts

A This was based on previous literature suggesting that under-resuscitation was associated with significant end organ damage secondary to ischemic injury. Inadequate resuscitation was similarly associated with the potential for hemodynamic collapse, resulting in death. Weight-based resuscitation programs and establishment of urine output guidelines have largely limited under-resuscitation at burn centers. However, burn patients now suffer from the consequences of over-resuscitation, in which patients receive even more fluid than recommended by the Parkland formula. These patients suffer from increased rate of burn infections, the development of acute respiratory distress syndrome, and abdominal compartment syndrome. In the clinical case presented, the Parkland formula would suggest that the patient receive approximately 4800 mL of resuscitation (4 × TBSA burn [20] × weight in kilograms [60]) within the first 24 hours. This patient received approximately double the amount. Regarding engraftment, there is no evidence that over-resuscitation worsens autologous skin graft engraftment. Conversion of burn injuries to deeper injuries is usually associated with under-resuscitation, as is end organ or digit ischemia. Deep venous thrombosis does not have any reported correlation with burn resuscitation.

A patient presents with an 8-cm linear laceration to the forearm from a bicycle accident. Compared with typical suturing techniques, which of the following outcomes is more likely with a cyanoacrylate glue-only closure? A) Dehiscence B) Hyperpigmentation C) Infection D) Keloid scarring E) Pain

A While cyanoacrylate glue closures such as Dermabond and Indermil offer the advantages of speed, ease-of-use, and comfort in the closure process, some studies show that the outcomes are unpredictable, especially for longer lacerations. One pediatric groin hernia incision closure showed a 24% dehiscence rate, while a porcine study of 10-cm lacerations showed a 15% dehiscence rate. Glue closures do have a role in smaller, tension-free lacerations, particularly in children or others who may not easily tolerate traditional closure. This simplicity of closure does come with the cost of a higher dehiscence rate, so glue closures may be inappropriate for longer, more complex wounds. When used as an adjunct to a comprehensive subdermal interrupted closure, it appears that the dehiscence rate normalizes. Data are less convincing on long-term scar results, but it does not appear likely that glue closures improve or worsen scarring to any appreciable extent for wounds that achieve primary healing without disruption.

A 65-year-old woman is evaluated because of nonhealing sores on her lower extremities. She has a history of alcoholism and is homeless. She appears cachectic, pale, and severely malnourished. She has lost most of her teeth; the gums are purplish and spongy in appearance. Skin examination shows numerous petechiae. Large, superficial, nongranular sores are noted on the legs. Scurvy is suspected. Which of the following processes is most likely to be adversely affected by this patient's nutritional deficiency? A ) Collagen cross-linking B ) DNA synthesis C ) Epithelialization D ) Fibroblast proliferation E ) Immune modulation

A collagen cross-linking via the hydroxylation of proline and lysine to hydroxyproline and hydroxylysine, respectively. The lack of cross-linking results in impaired collagen synthesis and a decrease in collagen tensile strength. Collagen-containing tissues, such as skin, dentition, bone, and blood vessels, are therefore affected, leading to the development of scurvy. The hallmark signs of scurvy are hemorrhaging in any organ (ie, petechiae, swollen gums), loss of dentition, and a lack of osteoid formation. Deficiency of vitamin C is rare in the United States; however, it can be seen in patients who are severely malnourished; have a history of alcoholism; or have restrictive diets for medical, social, or economic reasons. Other nutrients also play a major role in healing. Folate and vitamin B6 (pyridoxine) are integral in DNA synthesis and cellular proliferation. Vitamin A is an essential factor in epithelialization and fibroblast proliferation. Vitamin E is a strong antioxidant and immune modulator. Zinc is one of the most important micronutrients, as it acts as a cofactor for numerous metalloenzymes and proteins. It is essential for proper protein (like collagen) and nucleic acid synthesis.

Which of the following is the primary role of adipose-derived stem cells (ADSC) in wound healing? A) Assist in chemotaxis of platelets and granulocytes B) Differentiate directly into fibroblasts and keratinocytes C) Induce development of hair and sweat follicles D) Provide a scaffold for deposition of granulation tissues E) Register and organize pro-collagen fibrils

B Adipose-derived stems cells (ADSC) have had extensive study in vitro and in vivo because there are ready sources of them from adult patients, which bypasses many ethical and regulatory issues of embryonic stem cells. ADSC have both direct structural and paracrine roles in wound healing. They can directly differentiate into keratinocytes, endothelial cells, and dermal fibroblasts. ADSCs, through paracrine phenomena, are modulators of the inflammatory environment of the wound healing milieu but are not involved in the immediate chemotaxis during the inflammatory period nor do they function as a scaffold during the proliferative phase. Lysyl oxidase is the extracellular enzyme responsible for final alignment of collagen fibrils. Presence of skin adnexa such as hair follicles and sweat glands are hallmarks of scarless, fetal healing. Hair follicle formation typically only occurs during embryonic development and involves interaction of ectodermal and mesenchymal cells influenced by signaling pathways including Wnt/b-catenin and BMPl but not ADSCs.

A 40-year-old man with a history of seizure disorder presents with jaw pain and malocclusion 12 hours after he was punched in the face during a brawl. X-ray studies show a displaced left angle fracture and right parasymphyseal fracture. He smokes one pack of cigarettes daily. Open reduction and internal fixation of the fractures is planned. Which of the following factors in this patient's clinical presentation places him at greatest risk for postoperative wound infection? A) History of seizures B) History of tobacco use C) Patient age D) Patient gender E) Surgery delayed until 5 days after injury

B Although early treatment of mandible fractures would help relieve pain, delay of treatment in multiple series has not been directly correlated with an increased wound infection rate. In a recent review, tobacco use has been associated with a sixfold increase in wound infection compared with nonsmokers. Although the incidence of complications after mandible fractures is lower in children, in the adult population, patient age and gender do correlate with an increased complication rate. Factors that have correlated with a higher complication rate include the number of mandible fractures present and incision location, intraoral and combined intraoral, and combined intraoral and extraoral incisions were associated with higher infection rates than only extraoral incisions.

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

B 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. AlloDerm is a human cryopreserved, acellular, cadaveric, de-epidermalized dermis. The complex is immunologically inert and becomes repopulated with host fibroblasts and endothelial cells. Biobrane contains Type I porcine collagen peptides in a bilaminate of silicone film and nylon fabric. Integra is a temporary bilaminate composed of silicone and a matrix of cross-linked bovine tendon collagen and shark-derived glycosaminoglycans. 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.

Which of these situations is best suited for the use of a topical skin adhesive (polymerizing cyanoacrylate) for closure? A) Burst laceration along the eyebrow B) Over an intradermal repair of a vertical forehead laceration C) Over a suture repaired dog bite of the ear D) Straight line laceration on the cheek with 4 mm of separation E) Well apposed lip laceration crossing the vermilion cutaneous border

B Cyanoacrylate skin adhesives are sold as monomers that polymerize by an exothermic reaction on contact with air and fluids. They can be used in conjunction with other skin closure mechanisms such as sutures or as a primary skin closure device. There is evidence across multiple surgical specialties and situations that skin glues can save time in the operating room. When used correctly, the cosmesis is similar or better than external suturing. There are in vitro studies suggesting inhibition of Gram-positive cocci and clinical anecdotal evidence of decreased infection. There is evidence that when wounds are closed with skin glue as the only closure device that dehiscence rates are increased. If the adhesive leaks below the skin when applied, it can hold the edges open and delay or prevent healing with increased scarring or poorer cosmesis. Adhesives should be applied to well apposed skin edges only. The U.S. Food & Drug Administration-approved package insert for a major brand of skin adhesive (eg, Johnson & Johnson, Ethicon Dermabond) specifically indicates use on mucosa and over dirty wounds such as dog bites to be contraindicated. A burst laceration along the eyebrow and a straight line laceration on the cheek with 4 mm of separation would be contraindicated because of the lack of excellent epithelial continuity. Adhesive over a suture-repaired dog bite of the ear and a well-opposed lip laceration crossing the vermilion cutaneous border are specifically contraindicated on the package insert. Studies across multiple surgical specialties are supportive of cyanoacrylate skin adhesives over an intradermal repair of a vertical forehead laceration.

A 23-year-old woman comes to the office for evaluation of bilateral ear keloids. She reports that the keloids developed after she had her ears pierced 5 years ago. She has not had previous surgery for this problem. Which of the following is the most likely recurrence rate after surgical excision with injection of a corticosteroid? A) 5% B) 15% C) 35% D) 50% E) 75%

B Earlobe keloid formation after piercing is reported to affect approximately 2.5% of the population. Various adjuvant therapeutic modalities, including radiation therapy, intralesional corticosteroids, interferon, 5-fluorouracil, topical silicone, and pressure devices, are used to decrease recurrence rate after surgical excision. A recent meta-analysis looked at the recurrence rate of keloid formation after surgical excision with the use of radiation therapy and intralesional corticosteroids. Recurrence rate after excision with radiation therapy was found to be 14%. The recurrence rate after excision with intralesional corticosteroids was 15.4%. Although radiation therapy had an overall reduced recurrence rate, it was associated with higher cost and more significant potential complications. Five cases of carcinogenesis after radiation therapy have been reported. The main disadvantage of corticosteroid injections was found in most studies to be the pain of injection. Adjuvant corticosteroid injections in conjunction with surgery were performed preoperatively, intraoperatively, or postoperatively in various studies.

An otherwise healthy, 76-year-old woman sustains a deep partial-thickness facial burn following scald injury. No acute intervention is performed and the patient follows up in the clinic 6 weeks after the incident. She complains of pain in the right eye as well as frequent tearing. Physical examination of the eye shows 4 mm of lagophthalmos, conjunctival injection, and hypertrophic scarring on the upper lid with restrained motion. The surrounding skin on the cheek and forehead appears erythematous and indurated. Which of the following is the most appropriate treatment for this patient? A) Contracture release and forehead flap B) Contracture release and full-thickness skin grafting C) Contracture release and placement of allograft D) Contracture release and split-thickness skin grafting E) Scar massage and eyelid taping

B Facial burn injuries in the periorbital area must be quickly treated to support patient comfort and protect vision. Continued lagophthalmos and patient complaints warrant intervention, particularly with the degree of symptoms that the patient is expressing. The need for earlier intervention is specifically discussed in Klifto, et al. There is no indication for allograft placement following contracture release in this case, as a surface to graft upon should be present following contracture release in the eyelid. Of note, the contracture release usually occurs superficial to the orbicularis oculi and superior to the tarsal plate. Following contracture release, full-thickness skin grafts, but not split-thickness skin grafts, will minimize contracture after placement. Forehead flap reconstruction of the upper eyelid is a reasonable intervention and may be the most successful in preventing contracture recurrence, but it is not a treatment choice if the donor skin may be involved with the burn injury, as in the case of this patient.

A 36-year-old man with traumatic injuries, who is intubated and sedated in the intensive care unit, is noted to have extravasation of concentrated calcium solution from a peripheral access intravenous line. The consult is made immediately after extravasation. Which of the following is the most appropriate management of this injury? A) Intravenous administration of dexrazoxane B) Local injection of hyaluronidase C) Phentolamine infiltration D) Topical application of dimethyl sulfoxide E) Topical application of heat

B Hyaluronidase is an enzyme that breaks down hyaluronic acid, a mucopolysaccharide that is a normal component of the interstitial fluid barrier. It has been shown to increase the rate of absorption of an injected substance by facilitating diffusion of the substance over a large area. When injected locally within 1 hour of extravasation, it breaks down hyaluronic acid and decreases the viscosity of the extracellular matrix, and facilitates absorption and dispersal of the extravasated chemical. The ischemic effects of extravasated vasoconstrictive agents such as norepinephrine and dopamine may be reversed with local infiltration of phentolamine, which is an alpha-blocking agent. Topical heat application has been recommended in vinca alkaloid extravasation to promote local circulation and speed up clearance of the extravasated agent. Topical cooling in animal models has been demonstrated to increase ulcer formation. Dexrazoxane has been shown to antagonize the effects of several topoisomerase II poisons such as anthracycline agents, including doxorubicin. Recent clinical trials in Europe have demonstrated its efficacy in minimizing tissue damage from anthracycline extravasation if administered intravenously within 6 hours of extravasation. It is now the recommended initial treatment of anthracycline extravasation, especially in light of its FDA approval in 2007. Dimethyl sulfoxide (DMSO) is a free radical scavenger and an effective solvent. It may also have antibacterial, anti-inflammatory, and vasodilatory properties. Its topical application is effective in preventing ulcerations caused by doxorubicin extravasation.

Hyperbaric oxygen therapy (HBOT) is most appropriate for a patient with which of the following conditions? A) Acute osteomyelitis of the tibia B) Anaerobic necrotizing soft-tissue infection C) Chemical burn because of lye exposure D) Stevens-Johnson syndrome E) Wagner grade 2 diabetic foot ulcer

B Hyperbaric oxygen therapy (HBOT) is an accepted adjunct to surgical debridement, appropriate antibiotic therapy, and indicated critical care measures for necrotizing soft-tissue infections such as necrotizing fasciitis and Fournier gangrene. The increased oxygen delivery of HBOT improves leukocyte function and can enhance penetration of certain antibiotics such as aminoglycosides. The clinical effects include slowing of the progress of the infection and decreased risk of both amputation and mortality. There is not adequate evidence to justify HBOT in diabetic foot ulcers (DFUs) with Wagner grade 2 (extension to bone, tendon, or capsule) or less. However, there is moderate evidence to suggest benefit in DFUs with Wagner grade 3 (deep ulcer with osteomyelitis or abscess) or greater. HBOT may be indicated in the treatment of chronic osteomyelitis but not in the acute setting. It plays no role in the treatment of Stevens Johnson syndrome, and may be beneficial in acute thermal burns but is not indicated for chemical burns. The complete list of approved indications for HBOT, as determined by the Undersea and Hyperbaric Medical Society and the U.S. Food and Drug Administration, includes the following: Air or gas embolism Carbon monoxide poisoning Clostridial myositis and myonecrosis (gas gangrene) Crush injury, compartment syndrome, and other acute traumatic ischemias Decompression sickness Arterial insufficiency Severe anemia Intracranial abscess Necrotizing soft-tissue infections Refractory osteomyelitis Delayed radiation injury (soft tissue and bony necrosis) Compromised grafts and flaps Acute thermal burn injury Idiopathic sudden sensorineural hearing loss

A 45-year-old man sustains a facial laceration and develops a keloid scar. Compared with a hypertrophic scar, this patient's scar is most likely to have which of the following characteristics? A) Decreased fibroblast density B) Increased fibroblast proliferation rates C) Increased ratio of type III to type I collagen D) Regression of the scar over time E) Smaller and thinner collagen fibers

B Hypertrophic scars generally arise during the first few weeks following the initial scar, grow rapidly, and then regress. On the other hand, keloid scars appear later following the initial scar, and then gradually proliferate, often indefinitely. Both keloid and hypertrophic scars demonstrate increased fibroblast density. Keloid scars demonstrate increased fibroblast proliferation rates compared with hypertrophic scars. Keloid scars demonstrate a decreased ratio of type III to type I collagen. This is not observed in hypertrophic scars. Keloid scars demonstrate thicker, larger, and more randomly oriented collagen fibers compared with hypertrophic scars.

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

B 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 to delineate viable tissue early on and obviate prolonged demarcation. Cycles of freezing and thawing lead to greater inflammatory mediator release and, in the long run, greater tissue injury. Rapid warming decreases further tissue damage by halting both direct injury and continued release of secondary mediators. This occurs by submersion of the injured part in 104 °F (40 °C) water for 15 to 30 minutes. Use of radiant heat sources in frostbite can lead to iatrogenic injury because of uneven thawing and secondary thermal burn to insensate tissue.

A 38-year-old unconscious and intoxicated woman is brought to the emergency department after being struck by a motor vehicle. She sustained multiple injuries, including a wound on the right thigh, which measures 12 × 18 cm with areas of exposed fat and muscle. There is dirt and gravel in the wound. Which of the following is the most appropriate next step in management? A) Broad-spectrum antibiotic therapy B) Injection of tetanus toxoid C) Negative pressure wound therapy D) Split-thickness skin grafting E) Wound irrigation and debridement

B In a patient with a grossly dirty wound, it is appropriate to administer a tetanus shot. Tetanus (also known as lockjaw) is characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by Clostridium tetani, a gram-positive, rod-shaped, obligate anaerobe. Infection generally occurs through wound contamination and often involves a cut or deep puncture wound. In the acute period before definitive wound closure can be achieved, it is critical to debride all devitalized tissue such that there is a healthy, viable wound bed. The administration of broad-spectrum intravenous antibiotics has not been shown to decrease the risk of wound infection, and may, in fact, lead to the development of selecting out for resistant pathogens. The mainstay of treatment is performing repeat surgical debridement as often as necessary until the wound is clean. Debridement and cleansing of the wound are ideally performed in the operating room under controlled conditions; however, depending upon the condition of the patient, concomitant injuries, and the ability of the patient to tolerate the procedure, it may be necessary to perform a limited, conservative wound washout at the bedside or in the emergency department. Over the course of the initial hospital stay, debridement should continue until healthy tissue is encountered, which can be identified by visual inspection and the presence of punctate bleeding. The surgeon must consider several things when deciding between closure with a flap or a graft. The defect in this patient is too large to achieve primary closure. The use of negative pressure wound therapy for such a large wound may be helpful as a temporary measure, but, as a method of definitive wound closure, would result in healing by secondary intention, scarring, and prolonged wound care. If there were exposed bone, tendon, nerves, blood vessels, or significant dead space, this would make a stronger argument for a flap-over-skin graft. Although not provided as an option in this question, the use of biosynthetic materials or dermal matrix tissues has been reported in the literature as an intermediate step to skin grafting, but it is important to consider the necessity of these materials in effecting outcomes in light of the significant cost of using them. Split-thickness skin grafts can provide wound coverage over a large area. A mechanical dermatome is often used. Typical thicknesses may range from 8/1000th of an inch to 14/1000th of an inch. The graft can be meshed in various ratios such as 1:1.5, 1:2, and 1:3 to allow for a larger area of coverage per unit of harvested skin. It is important that the underlying wound bed be viable and free of necrotic tissue or infection to allow for healing of the skin graft ("skin graft take"). Adequate immobilization of a skin graft is important for "take" of the graft, and can be achieved with negative pressure wound therapy, or tie-over bolster dressing. The thigh has an abundant amount of soft tissue and muscle, which is why skin grafts are often sufficient for wound coverage rather than flaps.

Which of the following characteristics best distinguishes keloid scar tissue from hypertrophic scar tissue? A ) Collagen fibers parallel to the direction of wounding B ) Extension beyond original scar C ) Improved by surgical excision alone D ) Increased fibroblast density E ) Location on flexor surfaces and areas of motion

B Keloid scars differ from hypertrophic scars in that they can extend beyond the original scar, whereas hypertrophic scars are confined to the original boundary. Collagen fibers are wavier in keloids and more parallel in hypertrophic scars. Light and electron microscopic studies demonstrate that collagen in keloids is disorganized compared with normal skin. The collagen bundles are thicker and wavier, and the keloids contain hallmark ?collagen nodules? at the microstructural level. Surgical excision alone has a high rate of recurrence for keloids. Increased fibroblast density occurs in both hypertrophic scars and keloid scars and cannot be used to differentiate between the two. Keloids have increased fibroblast proliferation rates. Hypertrophic scars commonly occur on flexor surfaces and joints. Keloids have a high predilection for the sternum and earlobe.

Compared with standard wound dressings, postoperative negative pressure wound therapy is most likely to produce which of the following outcomes? A) Better delayed primary fascial closure rates for salvage laparotomy B) Better split-thickness skin graft incorporation C) Increased inflammatory response D) Increased postoperative dressing changes E) Increased risk of infection

B Multiple studies have shown the benefits of negative pressure wound therapy (NPWT) when used in conjunction with skin grafts, both as a bolster over a skin graft as well as wound bed preparation. NPWT has been shown to decrease the risk of infection in complex and traumatic wounds in some studies, while others have shown no difference in infection rates in complex wounds when the patient has multiple comorbidities or when used to cover uncomplicated incisions for elective orthopedic operations. However, there is no evidence to suggest NPWT increases infection risk compared with standard wound dressings. NPWT reduces both inflammatory response and edema formation. When used for damage control laparotomy and abdominal compartment syndrome, studies have failed to show any benefit of NPWT over standard dressings. Furthermore, at least one study has suggested an increased rate of enteric fistula formation is associated with NPWT. NPWT has been shown to decrease both the number of postoperative dressing changes and the number of additional operative interventions in complicated diabetic wounds.

Use of negative pressure wound therapy with a sponge dressing is likely to result in an adverse outcome in which of the following clinical scenarios? A) A hand wound with exposed tendons B) A lower extremity wound with exposed femoral vessels C) A Stage IV sacral pressure sore D) As a bolster over a split thickness skin graft on the arm E) Over a closed surgical incision after hernia repair

B Negative pressure wound therapy (NPWT) has dramatically improved our ability to manage complicated and complex wounds. Advantages of NPWT include decreased healing time, simplified wound care with less frequent dressing changes, and promotion of healthy granulation tissue. However, there are several contraindications to the use of NPWT. The presence of exposed vessels is an absolute contraindication to its use; arterial rupture has been reported with multiple fatalities. In addition to placement over exposed vessels, significant bleeding has also been noted with use of NPWT in groin and sternal wounds, in patients on blood-thinning medications, and during removal of well-integrated foam pieces. Other complications include infections due to retained pieces of foam. In addition to exposed vessels, NPWT should not be used in the setting of active, uncontrolled infection, malignant wounds, wounds with unexplored and/or nonenteric fistulas, and poorly debrided wounds. Although NPWT may not be the definitive wound management in the other scenarios listed, there is no contraindication for its use.

A 154-lb (70-kg), 45-year-old man undergoes excision and skin grafting after sustaining total body surface area burns to over 40% of his body. Using the Curreri formula, which of the following is this patient's total daily caloric need? A) 2250 kCal/day B) 3350 kCal/day C) 4450 kCal/day D) 5550 kCal/day E) 6650 kCal/day

B The Curreri formula is used to calculate caloric needs: 25 kCal/kg/day + 40 kCal/%TBSA/day. So 25 × 70 + 40 × 40 = 3350 kCal/day.

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

B 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.

An otherwise healthy, 32-year-old woman with a history of burns on 20% of the total body surface area of the left upper extremity and chest, returns 1 year after her injury for evaluation of a nonhealing wound over the dorsal elbow and limited range of motion at the joint. X-ray studies show soft-tissue lamellar calcification. Which of the following is the most likely diagnosis? A) Chronic osteomyelitis B) Heterotopic ossification C) Hypertrophic scar D) Marjolin ulcer E) Retained foreign body

B The most likely diagnosis is heterotopic ossification (HO). An important complication of massive burn injury (greater than 20 % BSA) is heterotopic ossification, with the elbow region being the most common site of occurrence. This may result in wound issues, stiffness, and nerve injury. HO can occur in 0.2 to 4 % of cases. Prevention of this condition includes radiation therapy and nonsteroidal anti-inflammatory drugs. Surgical excision is the procedure of choice for restoration of range of motion. Hypertrophic scars present as raised thickened scars following burn injury but do not show ossification within the scar. The most common scenario for development of a Marjolin's ulcer is malignant degeneration of a previous scar, usually squamous cell carcinoma. The latency period for development of this type of malignancy is usually 10 years after the original injury at the earliest. Chronic osteomyelitis would show radiolucency and changes within the bone not the soft tissue. The x-ray finding is not consistent with a retained foreign body.

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

B 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.

A 10-year-old girl is referred to the office because of a large, full-thickness cranial defect after sustaining a traumatic injury. Reconstruction with a split cranial bone graft is performed. Which of the following is the most likely mechanism by which the bone graft heals? A) Dural ossification B) Osteoconduction C) Osteogenesis D) Osteoinduction E) Vasculogenesis

B The most likely mechanism of split cranial bone graft healing is osteoconduction. The split cranial bone graft is primarily cortical. After it is separated from its blood supply, it serves as a nonviable scaffold for the ingrowth of blood vessels and osteoprogenitor cells from the recipient site. This process of osteoconduction, or ?creeping substitution,? eventually leads to resorption and replacement of most of the graft with new bone. The graft becomes fully osseointegrated with the recipient site. Spontaneous dural ossification can heal full-thickness cranial defects in infancy. After 12 to 18 months of age, the dura will not spontaneously ossify. Osteogenesis is the primary mechanism of bone graft healing for cancellous or vascularized bone grafts. Because these grafts are revascularized rapidly, osteoblasts survive the transplantation and produce new bone at the recipient site. Osteoinduction involves the stimulation of mesenchymal cells at the recipient site to differentiate into bone-producing cells. Demineralized bone and bone morphogenetic protein produce new bone primarily by osteoinduction. Vasculogenesis, the de novo formation of blood vessels from precursor cells, occurs during embryogenesis. Revascularization of split cranial bone graft occurs by angiogenesis, the production of new vessels from preexisting vasculature.

A 56-year-old man who works at a fertilizer production plant presents to the emergency department with 10% hydrofluoric acid burns to the palmar surface of both hands. He is in exquisite pain. Physical examination shows no other injuries. Which of the following is the most appropriate management of this burn injury? A) Application of a dilute alkali to neutralize the acid B) Copious surface irrigation and application of calcium gluconate gel C) Frequent electrolyte and renal lab analyses due to systemic toxicity D) Mafenide acetate (Sulfamylon) dressings E) Pain control and maintenance intravenous fluids

B The patient has sustained a hydrofluoric acid burn, an agent used in many industrial and domestic applications. Hydrofluoric acid is a unique acidic chemical agent because it can behave as a strong acid at higher concentrations and can also cause liquefactive necrosis, as alkalis do by the dissociation of fluoride ions into subcutaneous tissues. Fluoride ions combine with calcium resulting in local hyperkalemia, which is believed to be the cause for the "pain out of proportion" examination finding associated with hydrofluoric acid burns. Application of a dilute alkali is not recommended for the treatment of acidic burns because the resulting reaction can be exothermic, resulting in additional injury as the acid is being neutralized. For patients with greater than 5% total body surface area (TBSA) exposure to hydrofluoric acid or injury with less than 50% concentration of hydrofluoric acid, systemic toxicity can result, causing electrolyte disturbances and organ dysfunction. This patient's injury resulted from a low-concentration hydrofluoric acid exposure to a small surface area, making serial laboratory assessment less of a priority during presentation. Due to the intense pain that hydrofluoric acid burns can cause, pain control will be required for management, but maintenance fluid and pain control alone will not treat the burn injury. The hallmark of hydrofluoric acid chemical burn injury treatment is skin surface irrigation with copious amounts of water at lower pressure, followed by topical calcium gluconate to bind the fluoride ions before they penetrate into the soft tissues. This will neutralize the burn reaction, bind the fluoride ions, and help with pain control. Mafenide acetate is an appropriate topical antiseptic for non-chemical burns, but will not neutralize hydrofluoric acid.

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

B Theoretically, cultured epidermal autografts (CEAs), also known as cultured 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 ,000 for every 1% of the total body surface area that is ultimately covered.

A 30-year-old man who sustained burns on 35% of the total body surface area 24 hours ago is being treated in the burn unit. The patient was resuscitated according to the Parkland formula and is maintaining adequate urine output. Gastric feeding access was established on initial presentation, and the patient is being fed according to his initial body weight. Which of the following clinical indices is most suggestive of the need to decrease his feeding to trophic feeds? A) Early operative excision with planned start time in 8 hours B) Hypotension requiring vasopressin support C) Mild abdominal distension that is soft to palpation D) Nasogastric output of 100 mL for the past 24 hours E) Need for escharotomy

B There is no doubt that nutritional support for burn patients is integral. A multidisciplinary approach to nutritional assessment and support is ideal, and general knowledge of the indications of when to delay or decrease enteral feeding is essential. Since the patient has gastric and not post pyloric feeding access, nil per os (NPO) for eight hours allowing adequate gastric emptying to decrease risk of aspiration is necessary. Gut mucosal integrity is important during the stress of large trauma including burn, and enteral feeding is the preferred modality of access. However, during times of extreme stress, decreased splanchnic flow can cause poor intestinal perfusion, and there is the possibility of gut ischemia due to increased metabolic demand of the gut. Decreasing the gastric feeds to trophic feeds is recommended to decrease the risk of inducing gut ischemia. Clinical indications for threatened intestinal perfusion include firm, obvious abdominal distension and gastric output greater than 200 mL per day; the patient doesn't exhibit any of these clinical signs. Hypotension requiring vasopressor support indicated decreased perfusion, which can lead to possible mismatch of gut perfusion with required metabolic demand. Trophic feeds are recommended for patients who exhibit signs of significant decreased perfusion requiring vasopressor support. Escharotomy will increase fluid losses, but will not change caloric needs.

A 19-year-old man is undergoing open reduction and internal fixation of multiple facial fractures when the nasal endotracheal tube is accidentally disconnected from the breathing circuit. The surgeon, who is performing electrocauterization, witnesses an unexpected flash in the operative field. The surgeon immediately stops the procedure and alerts the anesthesiologist. Smoke and a burning odor coming out of the patient's airway are noted. Which of the following is the most appropriate next step in management? A) Decrease the flow of airway gases by half B) Immediately remove the endotracheal tube C) Pack the oral and nasal cavities with sponges D) Perform emergency bronchoscopy E) Reconnect the endotracheal tube

B This surgical team is confronted with a fire in the operating room, involving the airway. The most appropriate next step is immediate removal of the endotracheal tube, without waiting. The incidence of operating room fires in the United States is estimated to be around 600 cases per year. Fire requires the presence of three components: fuel, an oxidizer, and an ignition source. Common fuels in the operating room include alcohol-containing prepping agents, drapes and bandages, gowns and other personal protection equipment, petroleum jelly, etc. Ignition sources include the electrocauterization lasers, fiberoptic light sources, and defibrillators. The two most common oxidizing agents in the operating room are oxygen and nitrous oxide. Early warning signs of fire include unexpected flash, flame, smoke or heat, unusual sounds (e.g., a "pop," "snap," or "foomp") or odors, unexpected movement of drapes, discoloration of drapes or breathing circuit, and unexpected patient movement or complaint. The surgical procedure should be immediately halted so the team can evaluate whether fire is indeed present. In cases of airway fire, the ASA practice advisory recommends immediate (without waiting) removal of the tracheal tube, interruption of flow of all airway gases, removal of all sponges or any other flammable materials from airway, and pouring of saline into the airway. Once the fire is extinguished, subsequent steps consist of re-establishing ventilation, avoiding oxidizer-enriched atmosphere if clinically appropriate, examining of the endotracheal tube for possible fragments left behind in the patient's airway, and considering bronchoscopy.

A 45-year-old woman undergoes breast reconstruction with a transverse rectus abdominis musculocutaneous (TRAM) flap. During donor site closure, a size-0 absorbable suture that maintains the greatest strength over time is desired for closure of Scarpa fascia. Which of the following sutures is most appropriate? A) Chromic gut B) Poliglecaprone (Monocryl) C) Polydioxanone (PDS) D) Polyglactin (Vicryl) E) Polypropylene (Prolene)

C Chromic gut is an absorbable natural monofilament suture whose strength decreases to 50% in approximately 14 days, with near complete loss of strength at approximately 3 weeks. Polyglactin (Vicryl) is an absorbable synthetic polyfilament suture whose strength decreases to 50% in approximately 2 to 3 weeks, with near complete loss of strength at approximately 1 month. Poliglecaprone (Monocryl) is an absorbable synthetic monofilament suture whose strength decreases to 50% in approximately 7 to 10 days, with near complete loss of strength at approximately 3 weeks. Polydioxanone (PDS) is an absorbable synthetic monofilament suture whose strength decreases to 50% in approximately 4 weeks, with near complete loss of strength at approximately 6 weeks. Polypropylene is a a nonabsorbable synthetic monofilament suture.

A 7-year-old boy presents with a chief complaint of multiple wide and thin scars from skin lesion excisions. The patient's mother reports a history of late walking, hypermobile joints, and easy bruising. On the basis of these complaints, which of the following is the most likely diagnosis? A) Capillary fragility syndrome B) Cutis laxa C) Ehlers-Danlos syndrome D) Marfan syndrome E) Osteogenesis imperfecta

C Ehlers-Danlos syndrome (EDS) is the only diagnosis listed which encompasses all of the mentioned patient complaints. EDS encompasses a range of connective tissue disorders that share joint hypermobility, skin hyperextensibility, and tissue fragility. The different types of EDS have varying modes of inheritance and a variety of identified genetic mutations in collagen formation. Classical EDS is caused by an autosomal dominant mutation involving the COL5A1 or COL5A2 genes, which are involved in collagen type V synthesis. Common symptoms include skin hyperextensibility, widened atrophic "cigarette paper" scars, generalized joint hypermobility involving three or more joints, and easy bruising. Vascular EDS carries major risks, including arterial (aortic) dissection, rupture, or aneurysm. Cutis laxa is not associated with easy bruising. Capillary fragility syndrome typically does not present with late walking. Osteogenesis imperfecta and Marfan Syndrome are not associated with atrophic scarring.

A 24-year-old woman comes to the office because of painful nodules in both buttocks. She underwent buttock augmentation with injections of liquid silicone by an unlicensed practitioner 4 years ago. Excision of the affected area is performed. Histology of a specimen obtained from the excised tissue is most likely to show which of the following? A) Acellularity B) Calcification C) Granuloma D) Necrosis E) Thrombosis

C Free silicone liquid has a long history of use for soft-tissue augmentation. Little regulation of the practice and variable degrees of purity of the silicone have resulted in many disastrous complications, often occurring years after the initial injections. Potential adverse sequelae following silicone injection include migration, chronic induration and pigmentary changes, painful subcutaneous nodules, chronic infection, and ulceration. Many of the treated areas require radical resection and reconstruction. Histologic study of postsilicone injection nodules typically shows granulomas which develop after initial inflammation and fibrosis. Histologic evaluation of typical capsule formation around solid alloplastic prostheses, including breast prostheses, shows acellularity and organized layers of collagen. In the breast, free silicone injection may result in ductal obstruction, which may appear as calcification on mammography. Necrosis may be noted in ulcerative-type complications seen in intradermal injection. Intravascular injection can result in thrombosis and, rarely, embolism, resulting in death.

An 82-year-old man is referred for reconstruction of the scalp after Mohs micrographic surgery for an aggressive squamous cell carcinoma. He is scheduled to undergo radiation therapy as soon as possible after reconstruction. The patient has pulmonary fibrosis and is receiving oxygen via nasal cannula. Physical examination shows a vertex scalp defect of 4 × 4 cm with calvarium exposed throughout. Which of the following is the most appropriate management? A) Bilaminate neodermis B) Delayed reconstruction C) Local tissue rearrangement D) Radial forearm free flap E) Split-thickness skin graft

C In any reconstruction, many factors (local, regional, and systemic) have to be considered before deciding on a proper treatment option. Indeed, there may very well be multiple options. The patient described is an elderly man who is an extremely poor candidate for anesthesia (example of systemic consideration). Additionally, he will need radiation therapy to the scalp as soon as possible. Therefore, the reconstruction option needs to have excellent blood supply to heal in the first place, heal quickly, and withstand the effects of radiation. Additionally, coverage of the exposed calvarium is necessary, as periosteum has been removed by the Mohs surgeon. Out of the options given, local scalp flap coverage best accomplishes this goal. Delay of treatment is not recommended because it only creates a greater problem after radiation therapy, because all local options as well as the calvarium will be irradiated, which severely hampers the surgeon's ability to provide a low-morbidity procedure and avoid a substantial operation. Dermal matrices (any form) are not appropriate options here for many reasons. They are not the definitive treatment option in a patient who is about to undergo radiation. Once the matrices become incorporated, they will usually need a skin graft to complete reconstruction or they will need a prolonged period of dressing changes, neither of which is optimal in this patient (a second surgery or a prolonged healing phase). Also, they need to be placed on a well-vascularized bed in order for them to "take" and heal more effectively. An exposed calvarium (without additional burring of bone) is not an optimal bed for a dermal matrix. Skin grafts (of any variety) lack blood supply after harvest. They also need to be placed on a well-vascularized bed in order for them to "take" and heal more effectively. An exposed calvarium (without additional burring of bone) is not an optimal bed for a skin graft. Also, a thin skin graft may not be the best form of reconstruction in a patient who is about to undergo radiation therapy, if other options exist. Radial forearm free flap is too complex an operation for this patient with many comorbidities and a relatively small defect.

A 25-year-old man presents with partial-thickness burns involving 15% of the total body surface area that he sustained during a house fire. The patient is stabilized and resuscitated. Topical 1% silver sulfadiazine cream is applied to the burns. Which of the following properties is most characteristic of this antimicrobial agent? A) Greatly enhanced efficacy when compounded with thiol chelators B) Metabolic acidosis C) Poor capacity for wound bed penetration D) Poor efficacy against Candida albicans E) Potential for transient leukocytosis

C In the United States, silver is the most commonly used topical antimicrobial. It is available as a liquid solution of AgNO3 or ointments such as silver sulfadiazine (Silvadene). Despite its many advantages, its capacity to penetrate into the wound bed is limited to the surface epithelium, particularly in the presence of eschar because of the binding of silver ions to surface proteins. In this setting, different modalities should be used for optimal effects. Silver sulfadiazine is not only effective against Pseudomonas species and enteric bacteria, but it also provides coverage against fungi, including Candida albicans, with antimicrobial effects lasting up to 24 hours. Enhanced efficacy when compounded with thiol chelators is consistent with bismuth compounds, not silver. Bismuth is another heavy metal with antimicrobial properties. The most commonly used formulation of bismuth for wound care is bismuth subgalactate, found in xeroform (Covidien) gauze. This heavy metal disrupts biofilm formation by inhibiting polysaccharide capsule production in bacteria. Bismuth's antibacterial activity is enhanced when compounded with thiol chelators. Regarding the potential for transient leukocytosis, silver sulfadiazine has been shown to cause reversible neutropenia, which usually improves within a few days after discontinuation of the agent. Metabolic acidosis is associated with mafenide acetate use.

A 43-year-old woman comes to the emergency department 2 hours after sustaining deep second-degree burns to the right elbow from a campfire. The wound measures 8 x 20 cm. After surgical excision, placement of autografts, and coverage with petrolatum gauze, which of the following dressings is most likely to promote graft survival? A) Cotton balls and tie-over bolster dressing B) Dry gauze and compressive wrap C) Negative pressure wound therapy D) Occlusive dressing E) No additional dressing

C In the patient described, the most effective way to fixate autografts is negative pressure wound therapy (NPWT). Several studies in burn patients have demonstrated the superiority of NPWT over the other conventional dressings listed. Whether staples or sutures are used has little effect on graft survival, although sutures may offer more precise graft placement. Most dressings for graft fixation use petrolatum gauze of some form, followed by some type of dressing that offers compression to fixate grafts. Dry gauze and a compressive wrap is the simplest option. Cotton balls with a tie-over bolster dressing are also effective, especially for small grafts. Larger surface areas are more difficult to secure with this method. A simple occlusive dressing, while acceptable for a donor site, will not effectively fixate autografts. NPWT offers good graft fixation, exudate removal, and promotion of local perfusion, which may explain the improved graft survival observed.

A 32-year-old man is brought to the emergency department with a full-thickness thermal burn injury to the left ear. Which of the following therapeutic agents allows for the most effective preservation of involved cartilage? A) Acetic acid B) Honey C) Mafenide acetate D) Nanocrystalline silver dressings E) Silver sulfadiazine

C Mafenide acetate effectively penetrates burn eschar as well as cartilage and decreases the risk of suppurative chondritis in the setting of burns of the auricle. Twice-daily application is recommended. Care must be taken to monitor for metabolic acidosis, as mafenide acetate is metabolized to sulfamoylbenzoic acid, a carbonic anhydrase inhibitor. Silver sulfadiazine, nanocrystalline silver dressings, honey, and acetic acid have not demonstrated similar efficacy in preventing burn-associated chondritis.

A 46-year-old woman undergoes a fleur-de-lis abdominoplasty following successful gastric bypass surgery. She has a 94-lb (43-kg) weight loss and current BMI is 28 kg/m2. To ensure the best outcome for wound healing, which of the following is the recommended postoperative daily intake of protein for this patient? A) 20 to 30 g/day B) 40 to 50 g/day C) 60 to 70 g/day D) 80 to 90 g/day E) More than 100 g/day

C Nutritional status in postbariatric subjects is essential in achieving successful healing of surgical wounds. Anatomical changes to the gastrointestinal tract following bariatric surgery can exacerbate nutritional deficiencies and inadequacies. Reduced protein intake has been associated with significantly lower healing rates in massive weight loss patients. It is recommended that postbariatric patients consume 60 to 70 g/day of protein 2 to 4 weeks prior to surgery and for 1 to 2 months postoperatively.

A 63-year-old man underwent resection of a chest wall sarcoma that was covered with an anterolateral thigh flap. He now undergoes external beam radiation therapy, and there is erythema, edema, and dry desquamation of the surgical sites. Which of the following is the most appropriate treatment? A) Diphenhydramine B) Hyaluronic acid C) Hydrocortisone D) Salicylate E) Vitamin E

C Radiation dermatitis is one of the most common side effects of radiotherapy for cancer and can occur any time, from hours to weeks after radiation exposure. Acute radiation-induced skin changes depend on the radiation dose and include erythema, edema, pigment changes, epilation, and dry or moist desquamation. They can also be accompanied by pain and pruritis. For the lower grade changes described for this patient, topical corticosteroids with low to medium potency, such as hydrocortisone 1% cream, are recommended. This is in addition to a skin-washing protocol to keep skin clean and dry before treatments. All of the other topical agents listed - antihistamines, salicylate analgesics, vitamin E, and hyaluronic acid - have all been previously studied and shown to have no added benefit. More severe skin changes such as moist desquamation, skin necrosis, or intractable pain may require radiation to be stopped, resulting in inadequate disease treatment.

A 48-year-old woman undergoes excision of a 3-cm recurrent keloid of the presternal chest. Immediate reconstruction with a collagen-glycosaminoglycan scaffold dermal regeneration template is performed, followed by thin (0.008-in) epidermal autografting 21 days later. After it has healed completely, punch biopsy is performed. The absence of which of the following histologic features is most likely to indicate regenerated skin in this patient? A) Capillary loops at the dermal-epidermal junction B) Elastic fibers C) Hair follicles D) Neovascularization E) Rete ridges

C Regenerated skin is clearly quite different histologically from scar and, in fact, shares many characteristics with normal physiologic skin. Regenerated skin shows mechanical competence, vascularization, and heat and cold sensitivity. Furthermore, the dermal-epidermal junction shows formation of rete ridges and capillary loops. Regenerated skin displays elastic fibers and increased collagen fiber density in the reticular dermis, and it often exhibits nerve fiber regeneration as well. Regenerated skin, even when resurfaced with a split-thickness skin graft, however, does not have the dermal appendages such as hair follicles and sweat glands, that are present throughout normal skin.

Which of the following mechanisms is most likely to inhibit normal wound healing in a patient who smokes cigarettes? A) DNA strand breaks and helical cross-linking B) Increased cosubstrate for enzymes involved in collagen production C) Increased platelet aggregation D) Increased tissue oxygen delivery E) Nicotine-induced vasodilation

C The detrimental effects of smoking on wound healing are due primarily to nicotine, carbon monoxide, and hydrogen cyanide. One of the effects of nicotine is increased platelet aggregation due to enhanced adhesiveness of the platelets themselves. This leads to thrombus formation and decreased oxygen delivery. Nicotine does not produce vasodilation, but rather vasoconstriction. Both of these effects can lead to local tissue ischemia, which inhibits the normal wound healing process. One of the major mechanisms by which ionizing radiation inhibits wound healing is production of DNA strand breaks and helical cross-linking, but smoking is not significantly involved. Vitamin C is the vitamin which plays the greatest role in wound healing. It is required as a cosubstrate for hydroxylase enzymes, which are involved in the production of collagen. Vitamin C deficiency has long been known to inhibit wound healing (scurvy). However, supplemental vitamin C in the nondeficient patient has not been shown conclusively to produce any beneficial wound-healing effects.

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

C 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. Of the antibiotics listed, only vancomycin covers MRSA. Piperacillin-tazobactam is the most appropriate choice for pseudomonal coverage. Antifungal coverage with fluconazole or amphotericin is not necessary and is not supported by the literature. Antifungal prophylaxis remains controversial.

A 38-year-old electrician suffers an electrical burn to the right hand. Which of the following types of tissue has the lowest inherent resistance? A) Bone B) Fat C) Muscle D) Skin E) Tendon

C The tissue with the least resistance from the choices provided is muscle. The amount of electrical current that is conducted through tissue is proportional to the voltage and inversely proportional to the tissue's resistance, as is dictated by Ohm's Law, V=IR. Therefore, more current will flow through tissue with lower resistance, given all other variables being equal. Other variables that effect current flow include tissue volume and the amount of moisture. The body tissue with the highest inherent resistance is cortical bone, followed by cancellous bone, fat, tendon, skin, muscle, vessel, then nerve. So, in the setting of a high-voltage electrical burn, it is not uncommon to have more underlying structural and organ damage than the visible soft tissue damage may indicate. An EKG, cardiac monitoring, CBC, cardiac enzymes, and urinalysis for myoglobin may, therefore, be necessary for workup.

A 24-year-old man presents to the emergency department after sustaining burns from a workplace fire in a kitchen. He has a suspected inhalation injury. Physical examination shows partial-thickness burns on the forearms and thighs, as well as on one ear. The plan is to use mafenide acetate as a topical antimicrobial dressing. Because of the suspected lung injury, mafenide should be used with caution because it places him at increased risk for which of the following? A) Gray discoloration of skin B) Hyperosmolality C) Metabolic acidosis D) Methemoglobinemia E) Pruritis

C The topical use of mafenide acetate, a carbonic anhydrase inhibitor, can prevent the conversion of hydrogen ions in the body to carbonic acid, leading to metabolic acidosis. In patients with an inhalation injury and respiratory acidosis, the use of mafenide acetate over large surface areas can be fatal. The use of mafenide is common in areas with cartilage, such as the ear. It is also useful for eschar penetration. Common adverse effects include pain with application. Silver sulfadiazine is associated with leukopenia and hyperosmolality. Silver nitrate can also be used, but it causes gray-to-black staining of the wound and can also be associated with electrolyte imbalances. Methemoglobinemia has also been reported with silver nitrate use.

Negative pressure wound therapy with a sponge dressing is CONTRAINDICATED in which of the following clinical scenarios? A) An abdominal wound with an enteric fistula B) A dorsal hand wound with an exposed tendon C) A lower extremity wound with acute osteomyelitis D) Over a closed surgical incision E) A radiated scalp wound with exposed bone

C The use of negative pressure therapy (NPT) is contraindicated in wounds with active infection including osteomyelitis. Negative pressure dressings in these wounds convert an open, draining wound into a closed wound, which could potentially lead to abscess formation and/or sepsis. NPT has become an integral part of wound management over the past decade and a half. It is a commonly used wound dressing and/or chronic wound management tool. It is instrumental in acute wounds as well (e.g., lower extremity trauma, abdominal wall trauma), and as a skin graft bolster dressing. The major contraindications for its use include wounds with active infection such as untreated osteomyelitis, malignant wounds, wounds with exposed major vessels and/or organs, and wounds with unexplored and/or nonenteric fistulas. Apart from the infected wound, all the wounds mentioned in the option set may benefit from the use of NPT. It may not be the definitive management for those wounds, but it could be used as a temporary measure prior to the definitive treatment. Recently, studies have shown that the use of NPT over closed incisions may reduce the risk for dehiscence and infections.

An 8-year-old girl presents with burns on 60% of the total body surface area. Physical examination shows second- and third-degree burns involving her face, neck, and torso. After initial resuscitation, wound care, burn debridement, and skin grafting are performed, rehabilitation protocol is initiated. Administration of which of the following agents is most appropriate for improving bone mineral content (BMC) in this patient? A) Ascorbic acid B) Glutamine C) Insulin D) Oxandrolone E) Testosterone

D A randomized clinical trial of safety and efficacy of 1-year oxandrolone administration to severely burned children (over 30% total body surface area burns) demonstrated significant benefits of this medication. Improvements were noted in height, bone mineral content (BMC), cardiac work, and muscle strength, and were statistically higher compared to the control group. Mechanism of action is not totally clear but increase in insulin-like growth factor-1 secretion during the first year after burn injury, and, in combination with exercise, considerable increase in lean body mass and muscle strength has been demonstrated. The maximal effect of oxandrolone was found in children aged 7 to 18 years. No deleterious side effects were attributed to long-term administration. Oxandrolone, a synthetic oral nonaromatizable testosterone derivative, has only 5% of the virilizing activity and low hepatotoxicity when compared with testosterone administration. Oxandrolone reaches peak serum concentrations within 1 hour and is excreted through the urine. Oxandrolone binds to androgen receptors in the skeletal muscle to initiate protein synthesis and anabolism. Because oxandrolone cannot be aromatized to estrogen, the likelihood of estrogen-dependent bone-age advancement is reduced, making oxandrolone a safe therapeutic approach for growing children. Testosterone is not currently approved for treatment of burned children due to increased risks of virilization in female patients and aromatization effects among other health risks. Glutamine and ascorbic acid supplementation can aid in burn recovery; however, it has not shown to have similar effects on bone density as oxandrolone. Several studies support the use of enteral glutamine supplements in the adult burn population. Research has also shown that glutamine supplementation is favorable as it has the potential to decrease length of stay and associated costs through improving wound healing and decreasing rates of infection and mortality. Antioxidant therapies including: ascorbic acid; glutathione; N-acetyl-L-cysteine; vitamins A, C, and E; alone or in combination have been previously shown to protect microvascular circulation, mitigate changes in cellular energetics, decrease tissue lipid peroxidation, and decrease the volume of fluid required for resuscitation. Insulin is used to treat hyperglycemia and primarily used in diabetic patients. It may have limited use in burn care patients but has not shown to increase bone mineral density.

A 30-year-old man presents with a large open wound to the right thigh. The proposed treatment plan after debridement and establishing a clean wound is to use negative pressure wound therapy (NPWT). Which of the following is the main direct mechanism for wound healing by this method? A) Improvement in tissue auto-debridement B) Increase in collagen synthesis C) Reduction in wound bacterial load D) Removal of interstitial fluid leading to increased blood flow

D Based on the original studies by Moryk, it was hypothesized that the beneficial wound-healing effects of negative pressure wound therapy (NPWT) was a combination of a fluid-based mechanism and a mechanical stress mechanism. The fluid-based mechanism involves the removal of excess interstitial fluid from the wound bed by the vacuum, which results in the interstitial pressure decreasing below the capillary filling pressures, thus allowing "re-opening" of these wound bed capillaries. This leads to improved blood flow within the wound, allowing for granulation tissue formation. The mechanical strain mechanism is created by micro-strain forces created by the vacuum on the cells within the wound. Cellular deformation leads to numerous molecular changes, including activation of the vascular endothelial cell growth factor (VEGF) pathway, which enhance angiogenesis.Collagen synthesis is not directly affected by NPWT. There is equivocal evidence for whether there is a positive or negative effect of NPWT on wound bacterial loads. NPWT does not auto-debride wounds. It is important when using NPWT to ensure adequate mechanical debridement of nonviable tissues from the wound bed prior to initiating NPWT.

E-cigarettes are similar to traditional cigarettes in that the negative effect of nicotine on wound healing is primarily due to which of the following? A) Endothelial cell injury B) Increased inflammatory response C) Increased prostacyclin production D) Peripheral microvascular vasoconstriction E) Platelet aggregation

D Cigarette smoke contains thousands of different chemical substances including chemical toxins and carcinogens in addition to nicotine. While e-cigarettes are believed to have fewer health risks because tar and many other harmful chemicals have been removed, they do deliver vaporized nicotine. Nicotine-induced vasoconstriction in the periphery leads to relative skin ischemia and poor wound healing. Platelet aggregation is incorrect. Nicotine does not have a direct effect on platelets. In some studies, platelet aggregation appears to be reduced with long-term administration of nicotine. Increased prostacyclin production is incorrect. Prostacyclin is a local vasodilator with effects that minimize platelet aggregation. Nicotine has been shown to inhibit synthesis of prostacyclin. Increased inflammatory response is incorrect. Nicotine causes a diminished inflammatory response by a weakened chemotaxis, reduced migration, impaired bacterial killing by inflammatory cells and a subnormal release of proteolytic enzymes and inhibitors. Endothelial cell injury is incorrect. While nicotine can alter the structural and functional characteristics of vascular smooth muscle and endothelial cells, it does not cause cell injury. Several studies show increased number of endothelial cells in venous blood after nicotine administration in cigarette smokers, but not in non-cigarette smokers, suggesting that other harmful chemicals found in tobacco may contribute to cell injury.

A 41-year-old man undergoes an elective transplantation of the right hand 2 years after traumatic amputation in a machine accident. Postoperatively, the patient takes immunosuppressive medications to minimize the chance of rejection. To monitor for cellular rejection, observation and biopsy of which of the following tissue types in the postoperative period is most appropriate? A ) Blood vessel B ) Bone C ) Muscle D ) Skin E ) Tendon

D Composite tissue allotransplantation (CTA) has been performed on a host of tissues, though more recently in plastic surgery; this has largely been in the field of hand or upper extremity and facial transplantation. This requires immunosuppressive regimens which have had varying degrees of success, as well as issues with patient compliance, especially as these medications are expensive and, at least at this time, necessary for the rest of the patient's life. Skin is thought to be the most antigenic and immunoreactive tissue in CTA. Experience from China in hand transplantation demonstrated that cellular rejection in these patients was largely limited to the skin, with relative sparing of the underlying blood vessels, bone, muscle, nerve, and tendon. However, as the skin is an easily monitored tissue (versus solid organs), it is the most sensitive indicator of acute rejection in that it is clearly visible and can be easily evaluated by both patient and physician. Therefore, this tissue type is most appropriate to be monitored and biopsied.

Epithelial cell migration across an acute skin laceration is initiated by which of the following mechanisms? A ) Contraction of myofibroblasts B ) Deposition of collagen into the wound C ) Formation of a fibrin-fibronectin plug D ) Loss of contact inhibition E ) Secretion of anti-inflammatory products

D Epithelial cell migration is initiated by loss of contact inhibition and occurs from the periphery of the wound and adnexal structures. Cell division occurs in 48 to 72 hours, resulting in a thin epithelial cell bridge across the wound. A key role is played by epidermal growth factors. Myofibroblasts are involved in wound contraction and play no role in epithelialization. Collagen deposition is seen in the remodeling phase of wound healing. Fibronectin produced by fibroblasts serves as an adhesion molecule anchoring cells to collagen or proteoglycan substrates. Release of cytokines from platelets plays an important role in the initiation of the hemostatic initial phase.

In a patient with burns covering more than 30% of the total body surface area, which of the following parameters is most likely to increase in the first few hours of the pre-resuscitation phase? A) Cardiac output B) Peripheral blood flow C) Plasma volume D) Systemic vascular resistance E) Urine output

D Extensive burn injuries are characterized by the hemodynamic changes seen in hypovolemia, including decreased cardiac output, decreased peripheral blood flow, and decreased urine output. Decreased plasma volume is seen secondary to extravasation of plasma into the burn wound and surrounding tissues. Increased systemic vascular resistance is found in hypovolemia.

A 30-year-old man is evaluated one year after undergoing vascularized allograft transplantation at the midforearm level. Surveillance angiogram and duplex ultrasound show 60% closure of the ulnar artery and complete occlusion of the radial artery. The patient is adherent to the prescribed immunosuppressive therapy. Clinical evidence of chronic ischemia is suspected. Which of the following underlying processes is most likely in this patient? A) Deposition of preformed immune complex and complement activation B) IgA-mediated response C) IgM and IgG antigen-mediated response D) T-cell-modulated immune response

D Hypersensitivity reactions are divided into four different responses. Type 1 (allergy) refers to immediate release of IgE, mediated release of histamine, and other vasoactive mediators resulting in manifestation within minutes. Examples include asthma or anaphylaxis. Type 2 (cytotoxic-antibody dependent) refers to binding of IgM or IgG to the target cell, which in this case is a host cell. This results in the membrane attack complex (MAC) destruction of the targeted cell. Examples include thrombocytopenia, Goodpasture, and membranous nephropathy. Type 3 (immune complex-mediated reaction) refers to IgG binding to circulating antigen resulting in formation of an immune complex. These complexes can end up collecting in the vasculature, joints, and kidneys resulting in local destruction. Examples include rheumatoid arthritis, systemic lupus erythematosus, and serum sickness. Type 4 (delayed type hypersensitivity) refers to the activation of TH1 helper T cells by an antigen-presenting cell. This establishes an immune response memory and when activated again, the TH1 cells activate a macrophage-mediated response resulting in cellular damage. Examples include chronic transplant rejection, contact dermatitis, and multiple sclerosis.

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 × 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

D In high-voltage injuries, the electrical current often travels deep into the skin, causing internal damage that may not be readily visible. The current causes tissue damage at the entry point in the skin and along its path through the muscle, nerves, and bone. As electrical current is conducted through the body, heat is generated in direct proportion to the tissue resistance. 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. Immediate treatment is aimed at resuscitation of the patient, followed by salvage of the affected limb. The key to the acute management of electrical injuries to the upper extremity is to have a high index of suspicion for potential damage to deeper tissues, even at a distance from the point of contact. The optimal management of electrical injuries to the upper extremity includes initial exploration, decompression (fasciotomy), and aggressive repeated debridement, followed by reconstruction. Fasciotomy serves a dual role as both a therapeutic and diagnostic tool in the treatment of electrical injuries.

A 23-year-old African-American man presents with a raised thickened scar on his anterior chest that he complains is pruritic and unattractive. It was removed by another provider 4 years earlier and has slowly recurred over the past year. On examination, the lesion extends beyond the initial borders of the scar and is firm and hyper-pigmented. On review of his prior pathology report, which of the following histologic characteristics is most likely? A) Greater ratio of type III to type I collagen B) Multitude of myofibroblasts and smooth muscle actin C) Parallel collagen bundles D) Thick, wavy, and randomly oriented collagen fibers

D In patients with abnormal or excessive scar tissue formation, treatment and prognosis will be driven by the correct diagnosis of a keloid versus a hypertrophic scar. This patient presents with a recurrent keloid of the chest. His clinical history supports this diagnosis by recurrence after resection, growth extending beyond the original border of the lesion, late recurrence after several years, and continued growth over several years without regression or improvement. Hypertrophic scars are less likely to recur, contained within the original boundaries of the lesion, often regress somewhat within a year, and recur earlier in the postoperative period if they are to recur. Both hypertrophic scars and keloid scars can be pruritic. Pathologic analysis of keloids reveals more type I collagen than type III collagen, similar to normal skin. Hypertrophic scars will exhibit increased type III collagen and pro-fibrotic collagen cross-linking. Keloid growth is thought to be impacted by cell-signaling between keratinocytes and fibroblasts, but hypertrophic scar production requires an abundance of myofibroblasts expressing smooth muscle actin. While hypertrophic scars have parallel collagen fibrils and bundles, keloids are characterized histologically by thick, randomly oriented collagen fibrils that are not organized into bundles.

A 52-year-old man presents with a chronic ulcer of the lower extremity. Current medications include prednisone for management of rheumatoid arthritis. In addition to standard local wound care, which of the following treatments is most appropriate? A) Folate B) Hyperbaric oxygen therapy (HBOT) C) Long-acting insulin D) Vitamin A E) Vitamin C

D Malnutrition is a well-established risk factor for the development of chronic wounds. Vitamin A has been shown in multiple studies to offset the detrimental effects of corticosteroids on wound healing. Appropriate glucose management is critical to the treatment of diabetic ulcers, but insulin would not be indicated in the absence of uncontrolled diabetes mellitus. Vitamin C is required as a cosubstrate for enzymes involved in collagen production, and its supplementation is recommended for the nutritionally deficient. However, vitamin C has not been shown to be of any benefit to wound healing in the setting of chronic corticosteroid therapy per se. Hyperbaric oxygen therapy delivers oxygen to tissues by both hemoglobin-dependent transport and vastly increased dissolved oxygen content in blood when a patient breathes 100% oxygen at pressures well above atmospheric level. This improves wound healing by multiple cellular mechanisms in select wounds. However, benefits in treatment of chronic corticosteroid use have not been demonstrated. Elevated serum homocysteine has been associated in multiple studies with impaired wound healing and increased risk of coronary and cerebrovascular disease due to its enhancement of clotting pathways. Folate supplementation is often used to treat hyperhomocysteinemia, but conclusive benefit in chronic wounds is not as well-established.

Which of the following is associated with the use of pressure garments in the management of burn scars? A) Decreased scar strength B) Increased synthesis of tissue proteinases C) Larger and less densely packed collagen fibers D) Reduced differentiation of fibroblasts to myofibroblasts

D Significant differences in scar contraction were observed between scars receiving pressure garment therapy and control burns that received no pressure. Pressure garments exert compressive forces perpendicular and parallel to the surface of the scar. These forces oppose the direction of contracture. One hypothesis is that wound tension acts upon integrins by stretching them, which leads to phosphorylation of focal adhesion kinase and upregulation of smooth muscle actin and collagen production. When compression is applied to incisional wounds perpendicular to the wound tension, scarring is minimized. This suggests that the mechanical forces applied to the scar can assist in reducing differentiation of fibroblasts to myofibroblasts, decreasing scar contraction and collagen deposition. Scar strength was improved with pressure garment therapy compared with controls, with a 34% increase in ultimate tensile strength. Pressure garment therapy scars were also found to be composed of smaller, more densely packed collagen fibers. Increased synthesis of tissue proteinases is a mechanism of corticosteroids.

A 23-year-old woman comes to the office because of a hypertrophic scar after undergoing abdominoplasty 3 months ago. A multimodal approach to improving the appearance of the scar is planned. Which of the following therapies is supported by the highest quality evidence in this patient? A) Allium cepa extract B) Fat injection C) Microneedling D) Silicone gel E) Vitamin E

D Silicone gel has demonstrated efficacy in improving hypertrophic scars in a number of studies and is supported by level I evidence. Vitamin E, fat injection, allium cepa extract and microneedling are supported by lesser quality studies in a recent comprehensive review of the literature.

The use of routine systemic antibiotic prophylaxis is indicated in which of the following procedures? A) Abdominoplasty B) Carpal tunnel release C) Excision of squamous cell carcinoma of the skin D) Reduction mammaplasty E) Rhytidectomy

D Systemic antibiotic prophylaxis is recommended in clean breast surgery. Studies have shown that the use of antibiotic prophylaxis in patients undergoing breast surgery (with or without implant) significantly reduces the risk of surgical site infections. The benefit from routine antibiotic prophylaxis is greater in individuals receiving tissue expanders or breast implants for reconstruction, but patients undergoing breast augmentation or reduction mammaplasty also benefit from antibiotic prophylaxis. With the exception of cosmetic breast surgery, clean operations have not been shown to benefit from routine antibiotic prophylaxis. Therefore, the use of routine antibiotic prophylaxis is not indicated in clean surgical cases of the hand (carpal tunnel release), skin (squamous cell carcinoma of the skin), head and neck, or abdominoplasty. It is indicated in contaminated surgery of the hand or face.

A 154-lb (70-kg) man is evaluated 1 hour after sustaining deep partial-thickness burns to 50% of his total body surface area when attempting to light a gas grill. Paramedics administered 2 L of intravenous fluid during ground transport. Using the Parkland formula, which of the following is the starting rate for fluid resuscitation in this patient? A) 375 mL/hr B) 437 mL/hr C) 583 mL/hr D) 714 mL/hr E) 875 mL/hr

D The Parkland formula estimates the amount of crystalloid fluid needed for resuscitation of the burn patient, over the first 24 hours after injury. Volume needed = 4 mL × mass (kg) × % TBSA × 100. This patient would require 4 × 70 × 50% × 100 = 14,000 mL over the first 24 hours. Half of this, or 7 L, is given in the first 8 hours after injury. Because the patient received 2 L prior to arrival, during the first hour he would still need 5 L over the next 7 hours, or 714 mL/hr. Eight hours after injury, he would receive the other half, over 16 hours, or 437 mL/hr. It should be stressed that the Parkland formula serves as an initial guide to fluid resuscitation, and that actual volumes are titrated up or down, depending on urine output.

A 25-year-old man sustains a high-voltage electrical injury of the right upper extremity with an entrance wound over the volar aspect of the wrist. If increased compartment pressures are not adequately relieved in time, which of the following muscles is most likely to develop an ischemic contracture? A) Brachioradialis B) Extensor carpi radialis brevis C) Flexor carpi radialis D) Flexor digitorum profundus E) Palmaris longus

D The above patient did not undergo forearm compartment release and has flexion contractures of the interphalangeal joints of the fingers and thumb due to ischemic necrosis of the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL). Volkmann ischemic contracture is the end result of untreated compartment syndrome. The deeper muscles in the forearm sustain higher pressure sooner and for longer, causing them to be the most affected by compartment syndrome. The FDP to the middle and ring fingers lies against the ulnar and interosseous membrane in the deep compartment of the forearm. These two muscle segments, in addition to the remaining segments of the FDP to the index and small fingers and the FPL, are the most likely to develop contracture. All other muscles listed are more superficial. While brachioradialis, palmaris longus, extensor carpi radialis brevis, and flexor carpi radialis can all become necrotic in untreated compartment syndrome, FDP and FPL are the most likely to do so due to their depth in the forearm.

A 30-year-old man sustained a third-degree burn to his right arm from a flame while cooking over a grill. The burn is 5% total body surface area (TBSA). Two days after the injury, he undergoes debridement of the dorsal wrist and forearm. The paratenon is not present after the debridement. A bilaminate neodermis (Integra) graft is selected and placed on the wound. Use of this graft is associated with which of the following? A) Decreased cost to the hospital B) Decreased number of hospital stays C) Decreased number of surgeries D) Decreased risk for hypertophic scar E) Increased skin sensation after reconstruction

D The literature states that there is a decrease in hypertrophic scarring associated with the use of bilaminate neodermis (Integra) with burn reconstruction. The cost of the product is high. Use of the product requires a second surgery for the skin graft. There has not been any literature supporting improved sensation following use of the graft. The downside to the graft is that it can result in longer hospital stays for the patient in order to get the second surgery completed.

A 19-year-old man reports severe, worsening arm pain and finger swelling accompanied by distal numbness. He sustained a circumferential burn to the arm 12 hours ago. The area of burned skin itself is noted to be leathery and insensate. Examination demonstrates loss of distal pulses. Which of the following is the most appropriate next step? A) Angiography B) CT scanning C) Duplex ultrasonography D) Escharotomy E) Fasciotomy

D The most appropriate next step is escharotomy. The patient exhibits signs of vascular compromise due to tight restrictive burn eschar arising from a circumferential full-thickness burn. Edema following a burn due to inflammation and fluid resuscitation can cause increased swelling of the tissues, and the presence of tight circumferential eschar can give rise to vascular compromise. Release of the burn eschar (escharotomy) is indicated to relieve pressure on the tissues and allow for restoration of blood flow. Burns are classified into partial thickness and full thickness, and into different degrees based on the depth of injury. In the case of full-thickness (third-degree or fourth-degree) burns, the area of burned skin is insensate and may appear charred or leathery. Eschar formation in circumferential burns can lead to a tourniquet effect, with impaired circulation. In some cases, circumferential burns of the torso may even give rise to respiratory compromise or abdominal compartment syndrome. Escharotomy differs from fasciotomy in that the incision is made more superficially, to open the thick burn eschar, and does not need to extend deep to the fascia. Angiography would be useful in evaluating vasculature and blood flow, but would not be needed in this situation and would delay treatment. CT scanning can provide detailed imaging, but it would not be indicated in this situation and would delay treatment. Duplex ultrasonography can evaluate the presence of deep vein thrombosis, which could cause pain and swelling. However, in this case, the clinical scenario suggests that circulatory restriction is due to the circumferential burn scar. Fasciotomy is recommended in the case of increased compartment pressures, which may also present with pain, paresthesia, and loss of pulses, although in this instance the presence of a circumferential burn would indicate escharotomy as the treatment. Fasciotomy is advised if compartment pressure exceeds 30 mmHg, or if the difference between intracompartmental pressure and diastolic blood pressure is less than 30 mmHg.

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

D 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.

A 45-year-old man is brought to the burn unit after sustaining injuries during a house fire. Heart rate is 112 bpm, respiratory rate is 10/min, blood pressure is 113/63 mmHg, and oxygen saturation on room air is 98%. Physical examination shows charring of the face, singed eyebrows, and coarse breath sounds on inspiration. Which of the following is the most appropriate first step in management? A) Application of a face mask at 40% oxygen B) Bilevel positive airway pressure C) Hyperbaric oxygen therapy D) Intubation with 100% oxygen delivery E) Oxygenation with 6 L nasal cannula

D The patient is at risk for carbon monoxide (CO) toxicity and impending airway collapse. This patient was involved in a house fire and he has signs of lung injury. He should be intubated for airway protection because of his high potential for respiratory collapse. The patient's normal-appearing oxygen saturation is a result of CO poisoning leading to carboxyhemoglobin being mistaken for oxyhemoglobin. Getting a carboxyhemoglobin level will assist in the diagnosis. The treatment for CO toxicity is 100% inhaled oxygen, which will lead to dissociation of the CO molecule from hemoglobin. Hyperbaric oxygen treatment has been proposed as a potential treatment for CO toxicity, but the data are controversial, and treatment may be inappropriate in a burn patient undergoing resuscitation. Even though the patient has an oxygen saturation of 98%, it is falsely elevated in CO poisoning. This patient has stridor and is at risk for airway edema and should be immediately intubated. Bilevel positive airway pressure does not protect the airway.

During which of the following phases of wound healing is collagen deposition the greatest? A) Collagen deposition occurs equally during all phases of wound healing B) Collagen deposition does not occur during wound healing C) Inflammatory D) Proliferative E) Remodeling

D The proliferative phase of wound healing occurs in two phases. Fibrin and fibronectin are formed during the initial proliferative period. Around day 3 of wound healing, fibroblasts appear and begin production of collagen. The proliferative phase ends between 2 to 4 weeks of wound healing when collagen accumulation reaches a maximum and collagen remodeling begins, marking the beginning of the remodeling phase of wound healing. Inflammatory phase is dominated by white blood cells. There is an influx of polymorphonuclear leukocytes (PMNs), macrophages, and lymphocytes. PMNs are not essential to wound healing, but macrophages are essential. Sterile incisions normally heal without PMNs. Type III collagen is converted to type I in the remodeling phase. In this phase there are increased collagen cross-linking and increased tensile strength. Collagen deposition does not occur during wound healing is incorrect. It occurs during all phases of wound healing. Collagen deposition occurs equally during all phases of wounding healing is incorrect because collagen deposition is heaviest during the proliferative phase. Fibroblasts differentiate from resting mesenchymal cells in connective tissue. They are chemoattracted to the site, divide and produce components of ECM and their primary function is to synthesize collagen during that phase.

A 4-year-old boy is brought to a small community hospital by his grandmother, who reports that he fell into a bathtub filled with hot water while under the care of his stepfather. Physical examination shows deep partial-thickness burns on the lower extremities, including the feet, with a clear line of demarcation on the upper ankles; there are no splash marks. Multiple bruises scattered across the chest and periorbital ecchymoses are noted. Child abuse is suspected. Which of the following is the most appropriate next step? A) Admit the patient to the community hospital for a full skeletal survey B) Admit the patient to the community hospital for local wound care C) Notify local police to apprehend the stepfather D) Transfer the patient to a burn center by emergency medical services E) Transfer the patient to a burn center by private vehicle

D This child meets several criteria for transfer to a burn center: suspected child abuse, significant burns to the hands or feet, and a history that does not match the physical examination. While local police and the department of social services should be notified about this case, the role of the burn care provider is to make sure that the patient receives appropriate treatment and is transferred or discharged to a safe environment. The child will require assessment of the household by a social worker, as well as a pediatric consult to help look for other occult injuries, such as acute or healing long-bone fractures. Transfer to a burn center by private vehicle, despite the wishes of the family, would be placing the child at excessive risk for further injury. Transfer must be coordinated and performed by emergency medical services.

A 56-year-old woman who has been undergoing treatment for breast cancer has pain around the port site 6 hours after the extravasation of paclitaxel from a subcutaneous tunneled subclavian vein catheter. The patient is hemodynamically stable and breathing comfortably. Moderate swelling and tenderness are observed between the port and clavicle. Which of the following is the most effective management? A) Application of calcium gluconate gel B) Application of topical collagenase C) Line change over a wire D) Line removal and observation E) Operative debridement

D This patient has paclitaxel extravasation due to a malpositioned or leaking catheter with minimal symptoms; therefore, removal of the line and observation is warranted. Calcium gluconate gel is indicated after generously washing areas exposed to hydrofluoric acid as it neutralizes the fluoride ion. Topical collagenase is indicated in wounds with limited tissue necrosis and thus has no role in this patient. Changing this patient's line over a wire is contraindicated as the catheter is either malpositioned or broken. Although operative debridement is sometimes indicated in extravasation injuries, it is unusual, and expectant management is the norm. As this patient has no acute signs of compartment syndrome or tissue necrosis, line removal and observation are indicated. The incidence of extravasation is 0.01 to 6%. Chemotherapeutic agents that cause reactions are classified as irritants or vesicants. Irritants cause immediate and typically limited local reactions such as erythema, warmth, and tenderness. Common irritants are: bleomycin, carboplatin, carmustine, cisplatin, dacarbazine, etoposide, ifosfamide, and thiotepa. Vesicants can cause erythema, blistering, and skin necrosis. Itching in the absence of pain is common. In addition, vesicants can cause delayed ulceration that is self-perpetuated when the vesicant is rereleased upon lysis of affected cells. Common vesicants are: dactinomycin, daunorubicin, epirubicin, idarubicin, mechlorethamine, mitomycin, mitoxantrone, paclitaxel, vinblastine, vincristine. Paclitaxel is derived from the bark of the Pacific yew tree and induces microtubular assembly and stabilization, which leads to cell death. It is a vesicant, and if extravasation occurs, symptoms can range from localized pain, swelling, and erythema to severe skin necrosis and ulceration requiring surgical debridement. The vast majority of extravasations are managed non-operatively.

A 63-year-old man undergoes microdermabrasion for scar irregularity following treatment of facial skin cancer. Which of the following intraoperative findings signals the endpoint of treatment? A) Cobblestoned, yellow adiposity B) Confluent patches of bleeding lakes on a yellowish background C) Minimal dermis with visible subdermal plexus D) Pinpoint, punctate bleeding on a white background E) Thinned but present epidermis

D When performing microdermabrasion, the most appropriate endpoint is removal of soft tissue into the papillary dermis. The appropriate level in the papillary dermis is visualized as pinpoint bleeding in a white dermal background. Epithelial removal would be insufficient. Removal of tissue into the reticular dermis, either superficial or deep, increases the risk for scarring. The superficial reticular dermis demonstrates a yellowish white coloration and would reinforce the need to discontinue treatment before deeper injury occurs. Furthermore, dermal excisional depth would manifest as confluent red bleeding in a yellowish background of dermis or nearly complete dermal removal with a visible subdermal vascular plexus. If a full-thickness skin removal is performed (into the subcutaneous adipose layer), significant deformity could result. Preservation of adnexal structures to allow reepithelialization is a key tenet in determining the appropriate depth of treatment. Posttreatment changes include thickened epidermis and increased elastin and collagen.

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

E 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. Mortality for patients with TENS is 30%. The proposed mechanism is an acute autoimmune response to the basement membrane of epithelial structures, induced by drug exposure. Incidence is one case per million. 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. 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.

A 27-year-old man is evaluated in the intensive care unit for polytrauma 12 hours after sustaining burns on 10% of the total body surface area over the bilateral lower extremities during an industrial accident. The patient is sedated, intubated, and is being resuscitated appropriately. Examination shows the wounds are waxy and thick, but not circumferential. He has a nondisplaced fracture of the left tibia; physical examination of the left lower extremity shows that the toes are cool and cyanotic, which is markedly different from the right foot. Left lower extremity pulses are intact, but the left calf is much larger and firmer. Which of the following is the most appropriate next step in management of the left lower extremity? A) Ankle brachial index B) CT angiography C) Elevation D) Escharatomy E) Fasciotomy

E Compartment syndrome consists of increased pressure within enclosed compartments, resulting in decreased blood flow. For extremities, the concern is for muscle ischemia, as decreased perfusion is unable to supply the metabolic demand. The five P's of compartment syndrome (pain, pallor, paresthesia, pulselessness, and paralysis) are a good guideline, but are not entirely helpful in this case. As the patient is intubated, pain, paresthesia, and paralysis are unable to be assessed. Skin pallor is confused by the burn eschar, and pulselessness is an extremely late finding. Compartment syndrome needs to be diagnosed early for intervention to be effective. High clinical suspicion is mandatory for this patient because of his clinical condition and trauma. Although measurement of intracompartmental pressures can be done, his ongoing fluid resuscitation and current clinical examination would prompt an emergent surgical intervention. Elevation is not adequate treatment for compartment syndrome. Escharotomy would be inadequate as all four fascial compartments will need to be released. Although a circumferential eschar can cause compartment syndrome, this patient does not have circumferential eschar and has a tibial fracture, which points to requiring fascial release. CT angiography and ankle brachial index are good evaluations of flow and perfusion; however, they are not appropriate in the time sequence of this patient.

A 29-year-old man comes to the office because of scarring 12 weeks after he sustained extensive chemical burns to 30% of the total body surface area. Examination shows thick hypertrophic scarring of the upper extremities and anterior torso. Which of the following is the most appropriate management? A) Injection of a corticosteroid B) Scar band revision C) Serial casting D) Topical application of vitamin E E) Use of pressure garments

E Compression decreases blood flow to active scars, leading to decreased production of collagen fibers. This results in a balance of collagen synthesis and lysis that produces a flatter, softer, less vascularized scar. Clinically, burn scar hypertrophy is managed by use of pressure garments and inserts that must be worn almost 24 hours per day. They should be initiated as soon as all burn wounds have closed enough to tolerate wear and continued until the burn scar has matured. Initially, the pressure applied is low (15 to 17 mmHg). Then, as the scar progresses in maturation, custom-made pressure garments that provide 24 to 28 mmHg of pressure may be fabricated for the patient. The prompt institution of splinting techniques after the acute phase of burn injury can limit the development of long-term deformities. Splinting can combat edema, protect exposed structures and balance soft-tissue lengths to prevent contracture formation and compensate for functional deficits. Later, during the remodeling phase, serial casting can be a great adjunct to a therapeutic exercise program to restore normal range of motion. Surgical lengthening and scar band revision are options that are evaluated if hypertrophic scarring and contractures still develop after appropriate rehabilitation and management. Although the depth and distribution of the injury factor into the development of scars, the patient's own genetic predisposition also plays a role in scar formation and maturation. Injection of a corticosteroid can improve hypertrophic scars, but its use is limited to small, focused areas. Metabolic effects can be considerable. Due to the extent of scarring in this patient, corticosteroids are not an appropriate option. Although other topically applied therapies, such as creams containing vitamin E, have been widely used with the intent to improve wound healing, there is not substantial evidence to support regular use. Thirty-three percent delayed hypersensitivity reaction can be seen with topical vitamin E.

A 22-lb (10-kg), 18-month-old male infant is brought to the emergency department because of second- and third-degree thermal burns on the torso and lower extremities. Examination shows burns on 30% of the total body surface area. Administration of which of the following solutions is most appropriate for initial resuscitation of this patient? A) Hypertonic saline B) Normal saline C) Normal saline with 5% dextrose D) Ringer's lactate E) Ringer's lactate with 5% dextrose

E Fluid resuscitation is critical to combat the inflammatory response that occurs after a large burn and prevent the patient from going into shock. Burn injury leads to a combination of hypovolemic and distributive shock resulting from generalized microvascular injury and interstitial third spacing. The goal of fluid resuscitation is to ensure end-organ perfusion while avoiding intracompartmental edema. Ringer's lactate solution is a relatively isotonic solution that has been advocated as the key component for almost all resuscitation strategies during the first 24 to 48 hours. It is preferable to isotonic normal saline in large-volume resuscitation because its lower sodium concentration (130 mEq/L vs 154 mEq/L) and higher pH concentration (6.5 vs 5.0) are closer to physiologic levels. Ringer's lactate also has the potential added benefit of the buffering effect of metabolized lactate on the associated metabolic acidosis. Toddlers in particular are susceptible to inadequate fluid resuscitation and should be monitored closely to ensure adequate urine output of at least 1 mg/kg/hr. In children with burns greater than 15% total body surface area, weighing less than 20 kg and younger than 2 years of age, 5% dextrose should be added to the resuscitation fluid to prevent life-threatening hypoglycemia. These younger patients have lower hepatic glycogen reserves that can be quickly depleted after such significant injuries. Hypertonic saline and colloid solutions have been advocated and successfully used by some in large-volume resuscitation, but their use still remains controversial and not universally accepted in initial resuscitation.

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

E 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. The other options are helpful but not sufficient.

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

E 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.

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 interleukins 1 and 8 C) Increased B-lymphocyte function D) Increased levels of circulating immunoglobulins E) Increased T-suppressor lymphocyte function

E 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. TNF-a and IL-1 and IL-8 increase neutrophil chemotaxis into the wound as well as the upregulation of cell surface integrin receptors. These migrating neutrophils can degranulate, releasing proteases and oxygen-free radical species, leading to further tissue damage. Experimental studies using monoclonal antibodies directed against cell surface receptors have shown diminished tissue necrosis and a subsequent decrease in the surface area of burn. Diminished phagocytosis and reduced activation of complement result in diminished antibody-presenting complexes and membrane-attacking complexes. Along with diminished T-helper lymphocyte function, this results in decreased B-lymphocyte numbers, lymphocyte function, and levels of circulating immunoglobulins, especially immunoglobulin G. In addition to decreased production, circulating antibodies are also lost due to increased protein turnover and plasma leakage resulting from increased capillary permeability. Serum immunoglobulin levels gradually return to normal during the ensuing 2 to 4 weeks as the patient recovers. Impairment of cell-mediated immunity resulting from alterations in T-lymphocyte function is evidenced by a decrease in T-cell function and number, reduced T-helper and natural killer cell activity, and increased T-suppressor function and number. Impairment in T-cell mediated immunity is demonstrated by delayed rejection of allograft skin, suppression of graft-versus-host response, and skin hypersensitivity reactions. Better understanding of altered T-helper lymphocyte activity and the associated cytokine profiles may allow for immune-directed therapies that may decrease morbidity and mortality.

A 77-year-old man undergoes wide local excision of a melanoma on the posterior shoulder. Concomitant sentinel lymph node biopsy is positive for metastasis. Completion axillary lymph node dissection and adjuvant radiation therapy to the axilla are performed. Metastatic workup shows no abnormalities. Postoperatively, the patient develops chronically draining seroma and open wound to the axilla. He is referred for management of the radiation wound after it fails to improve with conservative local wound care. Physical examination shows a 2-cm open wound to the axilla, which tunnels 5 cm into the apex and is surrounded by extensive fibrosis and erythema. Which of the following interventions is most likely to result in a definitive closure? A) Administration of 30 hyperbaric oxygen treatments at 2.4 ATA B) Application of negative pressure wound therapy C) Excision of the wound cavity and full-thickness skin graft reconstruction D) Excision of the wound edges and application of acellular dermal matrix E) Wide excision of the irradiated soft-tissues and repair with a thoracodorsal artery perforator flap

E Radiation damage produces a hypoxic, hypovascular, and hypocellular environment that can lead to delayed healing and even ulcer formation. Principles of management once a chronic radiation wound has developed include aggressive surgical removal of the entire zone of injury, which is sometimes larger than initially anticipated, and repair with well-vascularized tissue. A thoracodorsal artery perforator flap will provide sufficient healthy and supple soft tissue to cover the entire axilla. The thoracodorsal pedicle should be intact as it is not regularly divided during axillary lymph node dissection. Negative pressure wound therapy would be contraindicated in this wound because of the potential for exposure of blood vessels in the axilla as well as for sponge retention in the tunneled wound and is, therefore, incorrect. Excision of the wound edges only may be inadequate treatment of the zone of injury, and it is not the best choice. Furthermore, acellular dermal allograft plays no role, aside from possibly a temporizing measure, in the treatment of radiation ulcers. Hyperbaric oxygen therapy is indicated for soft tissue radionecrosis. This delivers increased levels of oxygen to the hypoxic, irradiated wound and establishes a steeper oxygen gradient between the wound and surrounding tissues. The cellular response to this gradient stimulates neovascularization and can improve or even heal some wounds. However, with this large, cavitary wound, hyperbaric oxygen therapy, as a single-line treatment, would be unlikely to heal the wound completely. Excision of the wound cavity and full-thickness skin graft reconstruction is not the best option for two reasons. First, the excision may lead to exposure of neurovascular structures that should not be covered with a skin graft. Second, risk of partial or total loss of a full-thickness skin graft may be unacceptably high in an irradiated wound bed.

An 80-year-old woman undergoes excision and direct closure of a nasal sidewall carcinoma. The wound is closed with cuticular nylon suture and dressed with a temporary sterile gauze bandage in an uncomplicated office procedure with immediate discharge home. How long after surgery should this patient be advised to refrain from wetting the suture line with tap water rinses? A) 48 Hours after surgery B) 48 Hours after suture removal C) Until suture removal D) Until wound edge epithelization is complete E) No restriction

E Several studies have compared wet, moist, and dry wound healing following skin surgery without demonstrating an increase in infection rate when washing the wound with tap water at any point postoperatively as opposed to keeping the site dry for various lengths of time. This includes a rigorous randomized control trial in which patients with defects following skin lesion removal were divided into groups with tap water wound washing within 12 hours of surgery versus those asked to keep wound dry for 48 hours, where the incidence of surgical site infection in the wash group was not inferior to the dry group. On the other hand, unrestricted wound washing improves patient comfort, and multiple studies have demonstrated that wet or moist wounds promote reepithelialization and result in reduced scar formation with less inflammatory reaction compared to dry wounds.

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

E 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.

A 67-year-old woman comes to the office for follow-up examination 6 months after debridement of a chronic nondiabetic wound to the lower leg. Following the procedure, the patient was treated with moist dressings. Physical examination shows that the wound is healing less than 15% weekly. Persistent bacteria are suspected. Application of which of the following is the most appropriate nonsurgical management at this time? A) Alginate dressings B) Collagenase C) Film or transparent dressings D) Hydrogel dressings E) Silver ion-impregnated dressings

E Silver ions kill a broad spectrum of bacteria. No resistant organisms have been identified, and it is nontoxic to human cells. Alginates absorb up to 20 times their weight and are used to exudate wounds. Films and transparent dressings are waterproof and would be impermeable to bacterial contamination. Hydrogels are generally waterproof and would prevent bacterial contamination.

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)

E 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). Frostbite involves the formation of extracellular ice crystals that produce cellular damage. Rapid rewarming is the primary treatment for frostbite and has not changed in nearly three decades. 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. Addition of an antibacterial soap solution to the water bath is often recommended. The affected body part should then be splinted and elevated. It may take weeks or months for tissues to fully declare themselves. Delayed amputation is often required in severe frostbite injuries. Debridement and negative pressure wound therapy have not been shown to be an effective initial step in management compared with rapid rewarming, but they may have a role in secondary wound management. Hyperbaric oxygen (HBO) therapy has been reported as an adjunctive treatment to frostbite, but mostly as case reports. HBO may have a role in limiting the progressive tissue necrosis that follows the acute injury, but the lack of a prospective randomized controlled study has prevented it from achieving wide acceptance. Heparin and other anticoagulants and thrombolytics have been tried with some variable success, but they should be instituted only after rapid rewarming measures have been applied. There is experimental and clinical evidence to suggest that one of the mechanisms of tissue injury is thrombosis of the microvasculature that occurs from direct tissue injury and is mediated through free radicals. Primary amputation would not be appropriate as an initial step in management, as this would commit the patient to a morbid operation with significant disability. Gradual rewarming should not be used, as this has been associated with greater tissue injury.

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

E 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.

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

E 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.

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

E The patient described has a circumferential electrical injury to the forearm consistent with compartment syndrome. Fasciotomy is indicated. 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. Anticoagulation and embolectomy do not address the underlying problem, which is increased compartment pressure in a confined space. Burn excision is a method of removing devitalized burned tissue, usually in a tangential fashion down to the fascia, followed by split-thickness skin grafting. This is not a treatment for compartment syndrome. When there is circumferential injury of an extremity or in deep burns to the chest wall, escharotomy, or creating incisions through the burn eschar, is important in releasing constriction and allowing circulation to the extremity or airflow to the chest. Incisions must extend beyond the zone of the burn injury to assure complete release of the constriction to restore circulation. Escharotomy is performed within the first 24 hours of admission.

A 12-year-old boy is brought to the emergency department with a soft-tissue injury to the left knee after falling while playing football. Which of the following types of cells is most likely to appear first at the wound site? A ) Fibroblast B ) Lymphocyte C ) Macrophage D ) Neutrophil E ) Platelet

E The process of wound healing occurs as a sequence of overlapping processes. The appearance of cell types in an acute wound occurs in the following order: platelets, neutrophils, macrophages, lymphocytes, and fibroblasts, during the inflammatory phase. Tissue injury causes injured vessels to constrict rapidly, with primary hemostasis being a platelet-mediated process. Platelets trapped in the clot contain growth factors that initiate the coagulation and wound-healing cascade. The ensuing phases of wound healing consist of inflammation, collagen synthesis, angiogenesis, epithelialization, and remodeling. During the inflammatory phase, after platelet aggregation and degranulation, chemoattractants, activation factors, and vasoconstrictors are released. An efflux of neutrophils occurs at the wound site to primarily sterilize the wound. Within 2 to 3 days, the inflammatory cell population shifts to monocytes that differentiate into macrophages, which orchestrate the repair process. Collagen synthesis occurs as circulating bone marrow-derived cells migrate into the wound and develop a fibroblastic cell function. These cells and local, activated fibroblasts synthesize and secrete the replacement collagen scar. Fibroblasts become the predominant cell type by 3 to 5 days in clean, noninfected wounds. As fibroplasia progresses, granulation tissue forms as a consequence of neoangiogenesis and the directed growth of vascular endothelial cells stimulated by platelet and activated macrophage and fibroblast products. Wound reepithelialization occurs as keratinocytes at the wound margins migrate and proliferate once epidermal continuity is reestablished. Remodeling of the resultant scar is a dynamic process that occurs slowly over months to years. Collagen deposition and degradation occur to yield a mature scar; however, maximum tensile strength of a wound reaches only approximately 80% of noninjured skin.

Which of the following technical factors has the greatest favorable impact on the final appearance of a surgical scar? A) Closing the wound in a single layer B) Use of an absorbable suture C) Use of topical cyanoacrylate D) Retention suture E) Wound-edge eversion

E The two technical factors that increase the likelihood of a "good" scar are placement of sutures that will not leave permanent suture marks and wound-edge eversion. In wounds where the skin is brought precisely together, there is a tendency for the scar to widen. In wounds where the edges are everted or hypereverted in an exaggerated fashion, this tendency is minimized possibly by reducing the tension on the closure. While the most common method of closing a wound is with sutures, there is nothing necessarily superior about sutures or a specific type of suture. Staples, skin tapes, or wound adhesives are also useful in certain situations. Regardless of the method of closure or type of suture used, precise approximation of skin edges without tension is essential to ensure healing with minimal scarring. Simple interrupted suture is the gold standard for suturing wounds closed and everting the skin edges. Retention sutures tend to leave the most obvious and unsightly cross-hatching if they are not removed early. Wounds deeper than the skin are closed in layers. The key is to eliminate the dead space and provide a strong closure to prevent dehiscence and reduce tension. However, not all layers necessarily require separate closure.

A 42-year-old lineman is evaluated after sustaining a high-voltage electrical injury while working on a transformer. Physical examination shows entrance wounds on the volar aspect of the right distal forearm. He reports numbness and tingling of the little finger and weakness of the grip of the right hand. Which of the following is the most appropriate next step in management? A) Elevation of the forearm and observation B) Escharotomy and carpal tunnel release C) Escharotomy and excision of the burned tissue D) Fasciotomy of the forearm E) Fasciotomy and release of Guyon canal

E This lineman has developed compartment syndrome involving at least the ulnar nerve and has signs of motor and sensory impairment. Escharotomy is not an adequate release in electrical injuries, which often involve deeper structures, such as the pronator quadratus. Therefore, fasciotomy is required. While a carpal tunnel release should be performed in this case, release of Guyon's canal and decompression of the ulnar nerve in the forearm, wrist, and hand must be performed.

A 17-year-old boy undergoes excision of a congenital nevus of the scalp. Prior to excision, he underwent placement of a subgaleal tissue expander. Which of the following growth factors is most likely to be upregulated during ischemia in this patient? A) Epidermal B) Keratinocyte C) Platelet-derived D) Transforming E) Vascular endothelial

E Vascular endothelial growth factor (VEGF) is an important mediator of wound healing and is necessary for angiogenesis. It was originally discovered as a protein secreted by tumor cells to increase the permeability of local blood vessels to circulating macromolecules. It has been shown to increase endothelial growth and migration and enhance glucose transport in the endothelial cell, which is needed to match the increased energy required during angiogenesis. Hypoxia has been shown to be a potent stimulus for the expression of VEGF, and current research has been directed at utilizing VEGF to augment healing and viability in situations of tissue ischemia. The remaining growth factors are all important in the wound-healing process, relating primarily to reepithelialization and wound contraction, but are not directly involved in angiogenesis.

A 55-year-old woman who is wheelchair-bound has a stage IV ischial pressure ulcer. She has a history of systemic lupus erythematosus and multiple sclerosis. Medications include prednisone and gabapentin. BMI is 21 kg/m2 and has been stable for the past year. White blood cell count is 10.5 × 109/L, hematocrit is 30%, and serum albumin concentration is 3.6 mg/dL. After debridement of nonviable tissue, wound care is instituted. Supplementation with which of the following is most likely to promote wound healing? A) Echinacea B) Ferrous gluconate C) Glutamine D) Lipid emulsion E) Vitamin A

E Vitamin A is essential because it promotes epithelialization in collagen synthesis for wound healing, and supplementation is advocated in patients on chronic corticosteroid immunosuppressive medications such as prednisone. A 20,000-IU daily dosage can be useful for wound healing in immunosuppressed or irradiated patients and appears to reverse the wound healing-suppressive effects of the medication. Patients with chronic wounds frequently have some form of malnutrition that can impede the wound-healing process. In this case, the patient has a serum albumin concentration within the reference ranges, and a stable BMI, signifying adequate protein. In protein-deprived patients, supplementing amino acids that serve as the building blocks of protein synthesis is vital. L-arginine, in particular, has been shown to augment wound healing and collagen production. One study in elderly human subjects found that daily supplementation of 30 g of arginine aspartate for 14 days resulted in markedly enhanced collagen production and total protein. Ferrous gluconate is a useful supplement in iron deficiency anemia. This patient has borderline anemia, though not of a severity likely to be the central impediment to wound healing. Echinacea is a common herbal supplement used as an immunostimulant but has also been shown to have immunosuppressive effects. Lipid emulsion would be useful in a severely malnourished patient, though in this case, the patient's BMI is stable in the normal range. Of note, omega-3 fatty acids appear to inhibit the quality of collagen strength, and avoiding this common supplement during healing may be advisable.

A 50-year-old woman with a history of hypertension is brought to the hospital 1.5 hours after sustaining burn injuries in a house fire. Initial examination shows deep, second-degree burns (partial-thickness) to 35% of the trunk, non-circumferential third-degree burns (full-thickness) to 5% of the left forearm, and first-degree burns to 2% of the head. In addition to time from injury, which of the following common aspects of the burn evaluation should be used in both the Parkland formula and Brooke formula for determining fluid resuscitation in this patient? A) Total body surface area (TBSA) (determined by first-, second-, and third-degree burns), gender, weight B) TBSA (determined by first-, second-, and third-degree burns), weight C) TBSA (determined by second- and third-degree burns), age, weight D) TBSA (determined by second- and third-degree burns), gender, weight E) TBSA (determined by second- and third-degree burns), weight

E While there are different resuscitation formulas for initial burn resuscitation, such as the Brooke formula or the Parkland formula, they rely on giving a certain amount of fluid multiplied by total body surface area (as determined by partial- and full-thickness burns) and weight in kilograms of the patient. The fluid is then given initially as determined from time of injury, and divided into half given in the first 8 hours of injury and then half in the next 16 hours. This is a guideline only and resuscitation can be altered based on physiologic response, such as urine output. Gender and age are not a consideration and first-degree burns are not used in the calculation of total body surface area.

A 51-year-old farmer is brought to the emergency department after sustaining extensive burns in a fertilizer explosion. Examination shows white phosphorus embedded in his burn wounds. In addition to burn resuscitation and examination of the wounds under ultraviolet light, application of which of the following is the most appropriate next step in management? A) Calcium gluconate B) Mafenide (Sulfamylon) C) Mineral oil D) Polyethylene glycol E) Saline irrigation

E White phosphorus is sustained in both military and civilian circumstances. It is commonly found in fireworks, fertilizers, and pesticide. It is extremely volatile and can ignite spontaneously upon exposure to air. Additionally, phosphoric acids form during combustion and further injure tissues. Treatment mainstays include: Immediate debridement of visible debris Copious irrigation Keep the area wet and covered with saline-soaked gauze Cardiac monitoring and electrolyte evaluation. Profound hypocalcemia, hyperphosphatemia, and sudden death have been associated with this injury. Calcium gluconate gel is used in the management of hydrofluoric acid burns. Polyethylene glycol is used in the management of phenol and cresol burns. Mineral oil is used to isolate potassium, sodium, and magnesium from water, with which they react explosively. Mafenide (Sulfamylon) has no role in the immediate management of white phosphorus burns.

A 32-year-old man with a history of self-inflicted gunshot wound is evaluated because of significant facial deformity despite multiple complex reconstructive procedures. Composite tissue allotransplantation is performed. One episode of rejection is successfully treated 4 weeks postoperatively. Three months postoperatively, the patient develops recurrent swelling and hyperemia of the facial skin. Which of the following is the most likely cause of this condition? A) ABO incompatibility B) Acute rejection C) Antibody incompatibility D) Chronic rejection E) Hyperacute rejection

The most likely diagnosis is acute rejection, because this patient is still in the early postoperative period when acute rejection is most likely to occur (0 to 3 months). ABO incompatibility and antibody incompatibility would result in hyperacute rejection, which is mediated by the humoral immune system and occurs within minutes of transplantation. Chronic rejection occurs after years and is characterized by vasculopathy and fibrosis.

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 surface area 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

e Routine vital signs, such as blood pressure and heart rate, can be very difficult to interpret in patients with large burns. Catecholamine release during the hours after the burn can support cardiac output despite the extensive intravascular depletion that exists. 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. Tachycardia, normally a clue to hypovolemia, can be secondary to pain and is also almost universally present from the adrenergic state. Moreover, placement of a central line to measure the cardiac output in a morbidly obese patient may pose risks and should be avoided unless the burns involve the upper part of the body, which will lead to edema in the later stages of resuscitation. Blood pressure is not an accurate measure of tissue perfusion. 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]). 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. Several complicating factors exist with monitoring urine output as a guide for volume status and end-organ perfusion. 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.