An 18-year-old female suffers a 4% superficial partial-thickness burn to her right arm. At an outpatient burn clinic, she is treated with silver sulfadiazine and sent home. She presents to the emergency department 2 days later with increasing tenderness and erythema at the burn site. On examination, the wound appears dark brown and blood is present underneath the eschar. Viable tissue surrounding the eschar is biopsied, revealing >105 viable microorganisms per gram.
What is the most appropriate treatment for this patient?
Correct Answer: C
Aggressive surgical debridement and excision of infected tissues has substantially decreased the incidence of invasive burn wound infection and secondary sepsis. Burn wound infections are most often recognized based on the gross appearance of the burn and/or skin graft donor site and the rapid systemic changes (like signs of sepsis or new-onset enteral feeding intolerance). The presence of localized pain, erythema, color change, and premature separation of the burn eschar are all highly indicative of a burn wound infection.
The spectrum of microorganisms causing infections in burn patients varies with time and location. Immediately after thermal injury, primarily gram-positive bacteria from the patient’s endogenous flora or the external environment start to colonize the burn wound. The predominant grampositive organisms found in burn wound infections remain Staphylococcus aureus, followed by Enterococcus species. Endogenous gram-negative bacteria from the gastrointestinal flora also rapidly colonize the burn wound surface in the first few days after injury. Given their wide range of virulence factors and antimicrobial resistance traits, gram-negative bacteria have emerged as the most common etiologic agents of invasive infection. Pseudomonas aeruginosa remains the most frequent gram-negative microorganism isolated from burn wounds, followed by E. coli. Fungi (eg, Candida, Aspergillus, Fusarium, Mucor species) and multiresistant organisms (eg, methicillin-resistant Staphylococcus aureus [MRSA], vancomycin-resistant Enterococcus [VRE], Acinetobacter) appear late and typically occur after use of broad-spectrum antibiotics and/or a prolonged hospital stay. Candida sp. is the most common fungus isolated from burn wounds, and HSV-1 remains the most common viral organism.
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A 9-year-old male sustains 45% mixed superficial and deep partialthickness burns after falling into a campfire. During a prolonged ICU stay, he is persistently hyperglycemic, requiring regular insulin administration.
Which of the following correctly identifies two physiologic changes that are associated with the use of insulin within the burn population?
Correct Answer: B
In severely burned patients, insulin administered during acute hospitalization improves muscle protein synthesis, accelerates donor-site healing time, attenuates lean body mass loss and the acute phase response, and reduces infection and mortality rates. In addition to its anabolic actions, insulin exerts anti-inflammatory effects, potentially neutralizing the proinflammatory actions of glucose.
A 53-year-old female presents after being found unconscious in her house during a fire. Upon physical examination, you note that the patient has singed nasal hairs, carbonaceous sputum, and burns to her chin/forehead and is stridorous. You place her on 100% oxygen via a nonrebreather; however, her SpO2 remains in the low 80s, and she is tachypneic to 35. You are concerned for an inhalation injury.
What is the MOST sensitive test for diagnosing an inhalation injury?
Correct Answer: D
There are many reasons for intubating a burn patient, which includes concern for possible inhalation injury. Inhalation injury includes both direct, thermal injury to the airway as well as inflammation-induced injury to the parenchyma. Despite an overall decrease in burn mortality over the past couple of decades, inhalational injury remains one of the most critical injuries in this population with a mortality rate between 25% and 50%. The tenet of inhalation injury management is early diagnosis, which is critical to the survival of burn patients. Although singed nasal hairs, carbonaceous sputum, facial burns, and a history of closed space exposure can be found in patients with inhalation injury, they cannot be used alone to discriminate between patients with and those without inhalation injury. However, seeing these signs in addition to being found unconscious at the scene, stridor, and an overall high clinical suspicion should prompt the diagnosis of potential inhalation injury. The current accepted standard for diagnosis of inhalation injury is bronchoscopy. Endor and Gamelli created a grading system of inhalation injury based on bronchoscopic findings. These authors also demonstrated that survival was worse in those patients with higher grades of injury based on the bronchoscopic criteria in the figure that follows.
Grading of inhalation injury:
An 8-year-old male presented to your burn unit after sustaining 25% TBSA (total body surface area) superficial and deep partial-thickness scald burns to his torso and legs after a pot of boiling water fell onto him. After you complete your primary survey of the patient and adequate fluid resuscitation has begun, you evaluate the wound and note that the genitalia has been spared. You decide on silver nitrate soaks for your dressing as it is painless and readily available at your institution.
What side effect must you be worried about with this dressing?
Burn wounds are complicated, and their appropriate management is essential to the survival of the patient. If left untreated, the burn wound quickly becomes colonized by bacteria and fungi, which subsequently invade into the surrounding viable tissue and blood vessels, causing a systemic infection that will lead to death. Therefore, early treatment of these wounds is imperative to the health and survival of burn patients. The type of antimicrobial dressing is based on the characteristics of the wound.
Superficial (first-degree) burns result in minimal loss of the skin barrier; therefore, these wounds are usually treated with topical salves to help with pain and moisture control. Superficial partial-thickness (superficial second-degree) burns result in a higher loss of skin barrier than superficial burns. Despite this, the majority are able to be treated with dressing changes and do not require surgical excision. These wounds are treated with topical antibiotics and at least daily dressing changes. Sometimes, superficial partial-thickness burns can be treated with temporary biologic or synthetic dressings to help with burn wound healing. In cases of deep partial-thickness (deep second-degree) and full-thickness (third-degree) burns, surgical excision and grafting should be performed depending on the size and location of the wound. For these patients, the dressing regimen of choice should be based on helping to prevent infection until the burn can be excised.
Topical dressings can be divided into two broad groups: salves and soaks. Salves include 1% silver sulfadiazine (Silvadene), 11% mafenide acetate (Sulfamylon), polymyxin B, neomycin, bacitracin, mupirocin, and nystatin. Silvadene and bacitracin are the most commonly used given their broad antimicrobial coverage, as well as their easy applicability and high patient tolerance. The side effects of Silvadene include neutropenia and thrombocytopenia. Sulfamylon is also frequently used, as it is penetrates eschar (Silvadene does not), and is especially useful against Pseudomonas and Enterococcus species. Sulfamylon cream is primarily used in cartilaginous areas (such as the nose, ears), as well as areas where the tendons are exposed. A potential disadvantage of Sulfamylon is that sometimes patients complain of pain with application. Soaks include 0.5% silver nitrate solution, 5% mafenide acetate solution (Sulfamylon), and rarely 0.025% sodium hypochlorite solution (Dakin’s). Silver nitrate has complete antimicrobial effectiveness and is painless; however, this solution can cause staining of tissue. A potential complication of this product includes electrolyte leaching (as the solution is hypotonic). Methemoglobinemia is a very rare complication of silver nitrate. Sulfamylon is a carbonic anhydrase inhibitor; therefore, it can lead to metabolic acidosis.
A 47-year-old, 70 kg male presents as a transfer to the burn unit after sustaining a roughly 10% superficial burn, 30% superficial partialand deep-thickness burn, and a 20% full-thickness burn after being in a warehouse fire. There is no concern for inhalation injury. With the help of EMS and records from the outside hospital, you estimate that the time of injury was at 2 hours prior to arrival at your institution. En route to the outside hospital the patient receives 500 mL of lactated Ringer’s solution. At the outside facility and en route to your burn unit the patient receives an additional 1 L of lactated Ringer’s solution.
What would the additional 24-hour resuscitation requirements entail using the Parkland formula?
While institutions may have various different protocols for resuscitation (crystalloid, albumin) with differing end points (mean arterial pressure, urine output), fluid resuscitation remains the essential pillar of burn care. Children with >10% TBSA and adults with >15% TBSA require intravenous fluid resuscitation. The initial fluid used should be isotonic crystalloid, more specifically lactated Ringer’s. The use of albumin during fluid resuscitation has been debated.
The Parkland formula has become one of the most commonly used tools for guiding fluid resuscitation in a burn patient. In adult patients who have greater than 15% to 20% TBSA burns, initial 24-hour total fluid requirement is 4 mL/kg/%TBSA burned. Half of the total volume should be given within the first 8 hours post injury, with the remaining half given over the subsequent 16 hours (completing a 24-hour postinjury fluid resuscitation). It must be noted that superficial burns (previously known as first-degree burns) should not be used in the calculation of necessary fluid resuscitation when using these formulas. For children with greater than 10% TBSA burns, initial 24-hour total fluid requirement is 3 mL/kg/%TBSA burned. In addition, children usually require an additional maintenance rate based on their weight.
The American Burn Association recommends fluid resuscitation to begin at 2 to 4 mL/kg per TBSA burn percentage. A study performed by Chung et al. that was published in the Journal of Trauma and Acute Care Surgery in 2009 compared resuscitation of severely burned military casualties based on the modified Brooke formula (2 mL/kg) with the Parkland formula (4 mL/kg). Although the objective of the study was to evaluate the relationship between estimated volumes calculated and actual volumes received, the study found that patients who received resuscitation based on the modified Brooke formula received significantly less 24-hour fluid with similar morbidity and mortality. They suggested that patients who receive resuscitation based on the Parkland formula are at risk of excessive fluid and the implications that come with fluid overload.
With regard to the calculation for this question, the Parkland formula of 4 mL/kg per TBSA burn percentage is used. As mentioned previously, only partial- and full-thickness burns are included in the calculation of fluid resuscitation (30% for superficial partial- and deep-thickness burn, 20% for full-thickness burn, equaling 50% total in this patient’s case). The patient’s total fluid requirement for the first 24 hours post injury would be (4 mL) (70 kg) (50%) = 14,000 L. The patient must receive half of the resuscitation (7000 L) in the first 8 hours post injury. By the time the patient has presented to you, he is already 2 hours post injury. Therefore, he must receive the remainder of his resuscitation for this time period in 6 hours. In addition, he has already received a total of 1500 mL prior to his presentation to your hospital. For the remaining 6 hours post injury, he requires a rate of roughly 917 mL/h (7000 L − 1500 L = 5500 L); (5500 L/6 h = 917 mL/h). The remaining half of his total 24-hour postinjury resuscitation (7000 L) is given over the following 16 hours (7000 L/16 h = 438 mL/h).
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