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1384 SECTION 16: Environmental Injuries Thermal Burns E. Paul DeKoning EPIDEMIOLOGY More than 450,000 individuals in the United States receive medical treatment each year for burn injuries, with 486,000 receiving treatment in 2016 alone. 1 Although 40,000 patients require hospitalization and >60% of those are treated at one of 128 specialized burn centers,1 the vast majority of burn patients are treated in the acute setting by emergency physicians and discharged with outpatient follow-up. 2,3 Nearly 70% of burn victims are male, 1 and risk is highest between the ages of 18 and 35 years. Seventy-seven percent of all injuries are accounted for by fire or scalding; 43% of scald injuries occur in children <5 years of age. 4 Although overall survival exceeds 96%, fire, burn, and smoke inhalation still account for approximately 3400 deaths each year in the United States. 1 Elderly patients understandably have a dispro portionately higher death rate. 4-6 The risk of death from a major burn increases with larger burn size, older age, the presence of inhalation injury, and female sex. The Centers for Disease Control and Prevention lists the following groups as being at increased risk of fire-related injuries and death: children ≤4 years of age, adults ≥65 years of age, African Americans and Native Americans, persons living in rural areas, persons living in manufactured homes or substandard housing, and persons living in poverty. Care of the acute burn–injured patient has improved significantly over the past several decades. 8,9 The rate of hospital admissions has decreased owing to improvements in both the acute care provided in the ED and outpatient care at specialized burn centers. Indeed, over the past 50 years, dramatic improvements in survival after burn injury have been seen, in large part due to specialized burn care. 10 Only approximately 4% of those treated in specialized burn treatment centers die from their injuries or associated complications. 4,11 Additionally, survivors of high total body surface area (>20%) burns tend to have better 5-year survival than those with <20% total body surface area burns, because burn center survivors tend to be younger with fewer comorbidities. PATHOPHYSIOLOGY Skin consists of two layers: the epidermis and the dermis (Figure 217-1). Skin thickness varies both by age and anatomic location: It is relatively thinner at extremes of age, whereas it is thicker on the palms, soles, and upper back. Thus, the depth and severity of thermal injury vary by both the age of the victim and the anatomic location exposed. Skin functions as a semipermeable barrier to evaporative water loss, protects against environmental assault, and aids in the control of body temperature, sensation, and excretion. Partial-thickness thermal injury disrupts these barrier functions and contributes to free water deficits. This effect may be significant with moderate to large burns. Thermal injury results in a spectrum of local and systemic homeo static disorders that contribute to burn shock ( Table 217-1). These include disruption of normal cell membrane function, hormonal alterations, acid-base disturbance, hemodynamic changes, and hematologic derangement. The fluid and electrolyte abnormalities seen in burn shock are largely the result of alterations of cell membrane potential causing intracellular influx of water and sodium and extracellular migration of potassium, secondary to dysfunction of the sodium pump.
sturbance, hemodynamic changes, and hematologic derangement. The fluid and electrolyte abnormalities seen in burn shock are largely the result of alterations of cell membrane potential causing intracellular influx of water and sodium and extracellular migration of potassium, secondary to dysfunction of the sodium pump. In patients with burns >60% of total body surface area, depression of cardiac output results in a lack of response to aggressive volume resuscitation. Although disputed by others, Baxter and Shires 13 have explained this phenomenon to be due to circulating myocardial depressants. Systemic vascular resistance is increased. A significant metabolic acidosis may be present even in the early stages of a large burn injury. Massive thermal injury results in an CHAPTER Epidermis Dermis Subcutaneous layer Papillary layer Reticular layer FIGURE 217-1. Layers of the skin. Tintinalli_Sec16_p1333-1418.indd 1384 8/2/19 8:23 PM
esistance is increased. A significant metabolic acidosis may be present even in the early stages of a large burn injury. Massive thermal injury results in an CHAPTER Epidermis Dermis Subcutaneous layer Papillary layer Reticular layer FIGURE 217-1. Layers of the skin. Tintinalli_Sec16_p1333-1418.indd 1384 8/2/19 8:23 PM CHAPTER 217: Thermal Burns 1385 18% front 18% back 9% 9% 1% 18% FIGURE 217-2. Rule of Nines diagram for estimation of adult burn size. B B Relative percentages of areas affected by growth (age in years) Second-degreea nd Third-degree = Total percent burned 015 10 15 Adult C CC C 2 1 2 1 1 3 1 3 8 1 9 1 6 1 5 1 4 1 3 1 2 3 3 1 44 1 4 1 4 3 2 1 A: half of head B: half of thigh C: half of leg 2 2 2 3 33 1 3 1 1 3 FIGURE 217-3. Lund-Browder diagram for estimation of burn size. TABLE 217-1 Physiologic Effects of Thermal Injury • Disruption of sodium pump • Intracellular influx of sodium and water • Extracellular efflux of potassium • Depression of myocardial contractility (>60% of body surface area burned) • Increased systemic vascular resistance • Metabolic acidosis • Increase in hematocrit and increased blood viscosity • Secondary anemia from erythrocyte extravasation and destruction • Local tissue injury • Release of histamines, kinins, serotonins, arachidonic acids, and free oxygen radicals increase in hematocrit with increased blood viscosity during the early phase, followed by anemia from erythrocyte extravasation and destruc tion. Surprisingly, however, transfusion is seldom required for patients with isolated burn injury, and aggressive transfusion has been associated with increased morbidity and mortality. 14-16 Thermal injury is progressive. Local effects of thermal injury include the liberation of vasoactive substances, disruption of cellular function, and formation of edema. The subsequent systemic response alters the neurohormonal axis and further extends the injury. Impli cated in these events are histamine, kinin, serotonin, arachidonic acid metabolites, and free oxygen radicals. These substances exert their primary effects at the local level and cause progression of the burn wound. Although many factors may influence prognosis, the sever ity of the burn, the presence of inhalation injury, associated inju ries, the patient’s age, comorbid conditions, and acute organ system failure are most important. 5,6 Cell damage occurs at temperatures of >45°C (113°F) owing to denaturation of cellular protein. The size and depth of the resulting burn are functions of the burning agent, its temperature, and the duration of exposure. Burn wounds are described as having three zones: the zone of coagulation, in which tissue is irre versibly destroyed with thrombosis of blood vessels; the zone of stasis, in which there is stagnation of the microcirculation; and the zone of hyperemia, in which there is increased blood flow. The zone of stasis can become progressively more hypoxemic and ischemic if resuscita tion is not adequate. In the zone of hyperemia, there is minimal dam age to the cells and spontaneous recovery is likely. CLINICAL FEATURES BURN SIZE Burn size determines fluid resuscitation needs and the majority of decisions for hospital transfer. Burn injury size is quantified as the per centage of body surface area involved. 9 The Rule of Nines is a simple and commonly used method to calculate burn size ( Figure 217-2), It divides the body into segments that are approximately 9% or multiples of 9%, with the perineum forming the remaining 1%. Because of the proportionately larger heads and smaller legs of infants and children, this method must be modified in pediatric burn injury. A second method assumes that the area of the back of the patient’s hand is approximately 1% of their total body surface area .
s of 9%, with the perineum forming the remaining 1%. Because of the proportionately larger heads and smaller legs of infants and children, this method must be modified in pediatric burn injury. A second method assumes that the area of the back of the patient’s hand is approximately 1% of their total body surface area . The number of “hands” that equal the area of the burn can approximate the percentage of body surface area burned. A third and more precise method uses the Lund-Browder burn diagram (Figure 217-3). This allows an accurate age-adjusted determination of burn size for a given depth, allowing for the anatomical differences of children. BURN DEPTH The depth of a burn has historically been described in degrees: first, second, third, and fourth ( Table 217-2). However, a classification of burn depth according to the need for surgical intervention has become the accepted approach in burn treatment centers: superficial partial-thickness, deep partial-thickness, and full-thickness burns Tintinalli_Sec16_p1333-1418.indd 1385 8/2/19 8:23 PM
cond, third, and fourth ( Table 217-2). However, a classification of burn depth according to the need for surgical intervention has become the accepted approach in burn treatment centers: superficial partial-thickness, deep partial-thickness, and full-thickness burns Tintinalli_Sec16_p1333-1418.indd 1385 8/2/19 8:23 PM 1386 SECTION 16: Environmental Injuries TABLE 217-2 Burn Depth Features Classified by Degree of Burn Burn Depth Histology/Anatomy Example Healing Superficial (first degree) Epidermis Sunburn 7 d No blisters, painful Superficial partial-thickness (superficial second degree) Epidermis and superficial dermis Hot water scald 14–21 d, no scar Blisters, very painful Deep partial-thickness (deep second degree) Epidermis and deep dermis, sweat glands, and hair follicles Hot liquid, steam, grease, flame 3–8 wk, permanent scar Blisters, very painful Full-thickness (third degree) Entire epidermis and dermis charred, pale, leathery; no pain Flame Months, severe scarring, skin grafts necessary Fourth degree Entire epidermis and dermis, as well as bone, fat, and/or muscle Flame Months, multiple surgeries usually required TABLE 217-3 Burn Depth Features: American Burn Association Burn Classification Burn Classification Burn Characteristics Disposition Major burn Partial-thickness >25% BSA, age 10–50 y Partial-thickness >20% BSA, age <10 y or >50 y Full-thickness >10% BSA in anyone Burns involving hands, face, feet, or perineum Burns crossing major joints Circumferential burns of an extremity Burns complicated by inhalation injury Electrical burns Burns complicated by fracture or other trauma Burns in high-risk patients Burn center treatment Moderate burn Partial-thickness 15%–25% BSA, age 10–50 y Partial-thickness 10%–20% BSA, age <10 y or >50 y Full-thickness burns ≤10% BSA in anyone No major burn characteristics present Hospitalization Minor burn Partial-thickness <15% BSA, age 10–50 y Partial-thickness <10% BSA, age <10 y or >50 y Full-thickness <2% in anyone No major burn characteristics present Outpatient treatment Abbreviation: BSA = body surface area. (Table 217-3). Determination of burn depth requires clinician judg ment using commonly observed wound features. There is no objec tive method of measuring burn depth, and burn wound biopsy is not routine practice. A superficial burn involves only the epidermal layer of skin. Sunburn is frequently given as an example, even though it is caused by ultraviolet light instead of thermal injury. 18 The burned skin is red, painful, and tender without blister formation. Superficial burns usually heal in about 7 days without scarring and require only symptomatic treatment (Figure 217-4). Partial-thickness burns extend into the dermis and are subdivided into superficial partial-thickness (Figure 217-5) and deep partialthickness burns (Figure 217-6). In superficial partial-thickness burns, the epidermis and the superfi cial dermis (papillary layer) are injured, while the deeper layers of the FIGURE 217-4. Superficial burn. dermis, hair follicles, and sweat and sebaceous glands are spared. Superficial partial-thickness burns are often caused by hot water scalding. The skin is blistered, and the exposed dermis is red and moist. These wounds are exceedingly painful to touch. The dermis is well-perfused with intact capillary refill. Healing typically occurs in 14 to 21 days, scarring is usually minimal, and there is full return of function. Deep partial-thickness burns extend into the deep dermis (reticular layer) (Figure 217-6). Hair follicles and sweat and sebaceous glands are damaged, but their deeper portions usually survive. Hot liquids (e.g., oil or grease), steam, or flame usually cause this type of injury. The skin may be blistered, and the exposed dermis is pale white to yellow in color.
he deep dermis (reticular layer) (Figure 217-6). Hair follicles and sweat and sebaceous glands are damaged, but their deeper portions usually survive. Hot liquids (e.g., oil or grease), steam, or flame usually cause this type of injury. The skin may be blistered, and the exposed dermis is pale white to yellow in color. The burned area does not blanch; it has absent capillary refill and absent pain sensation. Deep partial-thickness burns may be dif ficult to distinguish from full-thickness burns. Healing takes 3 weeks to 2 months; scarring is common and related to the depth of the dermal injury. Surgical debridement and skin grafting may be necessary to obtain maximum function. Tintinalli_Sec16_p1333-1418.indd 1386 8/2/19 8:23 PM
artial-thickness burns may be dif ficult to distinguish from full-thickness burns. Healing takes 3 weeks to 2 months; scarring is common and related to the depth of the dermal injury. Surgical debridement and skin grafting may be necessary to obtain maximum function. Tintinalli_Sec16_p1333-1418.indd 1386 8/2/19 8:23 PM CHAPTER 217: Thermal Burns 1387 FIGURE 217-5. Superficial partial-thickness burn. FIGURE 217-6. Deep partial-thickness burn. FIGURE 217-7. Full-thickness burn. TABLE 217-4 American Burn Association Burn Unit Referral Criteria • Full-thickness/third-degree burns in any age group • Partial thickness burns >10% total body surface area • Burns involving the face, hands, feet, genitalia, perineum, or major joints • Electrical burns, including lightning injury • Chemical burns • Inhalation injury • Burn injury in patients with preexisting medical disorders that could complicate management, prolong recovery, or affect mortality • Burn injury in any patients with concomitant trauma (e.g., fractures) in whom the burn injury poses the greatest risk of morbidity or mortality • Burn injury in children in hospitals without qualified personnel or equipment to care for children • Burn injury in patients who will require special social, emotional, or long-term rehabilitative intervention • Burn injury in children <10 y and adults >50 y of age Because all dermal elements are destroyed, these injuries do not heal spontaneously. Surgical repair and skin grafting are necessary; sig nificant scarring is the norm. Fourth-degree burns are those that extend through the skin to the subcutaneous fat, muscle, and even bone. These are devastating, life-threatening injuries. Amputation or extensive reconstruction is sometimes required. BURN CENTER TRANSFER The American Burn Association provides guidelines for referral to a burn center, in addition to indications based on burn depth ( Table 217-4). 9,19 Children <10 years of age and adults >50 years are considered high-risk patients. Patients with significant comorbidities, such as heart dis ease, diabetes, or chronic pulmonary disease, are also likely to require Full-thickness burns involve the entire thickness of the skin (Figure 217-7). All epidermal and dermal structures are destroyed. These injuries are typically caused by flame, hot oil, steam, or contact with hot objects. The skin is charred, pale, painless, and leathery. Tintinalli_Sec16_p1333-1418.indd 1387 8/2/19 8:23 PM
l-thickness burns involve the entire thickness of the skin (Figure 217-7). All epidermal and dermal structures are destroyed. These injuries are typically caused by flame, hot oil, steam, or contact with hot objects. The skin is charred, pale, painless, and leathery. Tintinalli_Sec16_p1333-1418.indd 1387 8/2/19 8:23 PM 1388 SECTION 16: Environmental Injuries prolonged care and should be considered for transfer to a burn unit. Burn severity, underlying medical and social conditions, and the capa bilities of the institution initially receiving the patient must all be considered in the decision to transfer the patient to a burn unit. INHALATION INJURY As treatment of burn shock and sepsis has improved, inhalation injury has become the main cause of mortality in burn patients. Most fire-related deaths are due to smoke inhalation. 5,6,11 Inhalation injury is associated with closed-space fires and conditions that decrease mentation, such as overdose, alcohol intoxication, drug abuse, and head injury. Exposure to smoke includes exposure to heat, particulate matter, and toxic gases. Direct thermal injury is usually limited to the upper airway; thermal injuries below the level of the vocal cords can occur in cases of steam inhalation. Smoke contains particulate matter, usually <0.5 µm in size, which is formed from incomplete combustion of organic material. Small particles may reach the terminal bronchioles, where they can initiate an inflammatory reaction that leads to bronchospasm and edema. Toxic inhalants are divided into three large groups: tissue asphyxiants, pulmonary irri tants, and systemic toxins. 20 The two major tissue asphyxiants are carbon monoxide and hydrogen cyanide. Carbon monoxide poisoning is a well-known consequence of smoke inhalation injury. Severe carbon monoxide poisoning produces brain hypoxia and coma. Comatose patients lose airway protective mecha nisms, which may result in aspiration and further pulmonary injury. All patients with suspected carbon monoxide exposure should receive 100% oxygen by non-rebreather mask and should be evaluated for hyperbaric oxygen therapy (see Chapter 222, “Carbon Monoxide”). Hydrogen cyanide is formed by the combustion of nitrogen-containing polymers such as wool, silk, polyurethane, and vinyl. Cyanide binds to and uncouples mitochondrial oxidative phosphorylation, which leads to profound tissue hypoxia. Specific treatment for cyanide toxicity may be required (see Chapter 204, “Industrial Toxins”). Inhalation injury damages endothelial cells, produces mucosal edema of the small airways, and decreases alveolar surfactant activity, resulting in bronchospasm, airflow obstruction, and atelectasis. Although lower airway edema may not be clinically evident for up to 24 hours, upper airway edema can occur rapidly. Over time, tracheal and bronchial epithelial sloughing occurs. Approximately half of intubated burn patients admitted to burn centers develop acute respiratory distress syndrome. 21 The most recent international guidelines for the management of burn injuries suggest lung-protective strate gies including using low tidal volumes in patients with acute respira tory distress syndrome. Specifically, maintaining plateau pressures below 31 cm H 2O and tidal volumes below 7 mL/kg is indicated. Prophylactic antibiotics and corticosteroids are not recommended in inhalation injury. 10 Therefore, when inhalation injury is present, careful fluid resuscitation guided by hemodynamic monitoring can help avoid pulmonary edema and acute respiratory distress syndrome.
H 2O and tidal volumes below 7 mL/kg is indicated. Prophylactic antibiotics and corticosteroids are not recommended in inhalation injury. 10 Therefore, when inhalation injury is present, careful fluid resuscitation guided by hemodynamic monitoring can help avoid pulmonary edema and acute respiratory distress syndrome. The initial diagnosis of smoke inhalation is made from a history of exposure to fire in an enclosed space and physical signs that include facial burns, singed nasal hair, soot in the mouth or nose, hoarseness, carbonaceous sputum, and expiratory wheezing. No single method for diagnosing the extent of inhalation injury exists. Measurement of arterial carboxyhemoglobin is used to document prolonged exposure to products of incomplete combustion. The chest radiograph may be normal initially. Bronchoscopy and radionuclide scanning may also be helpful in evaluating the full extent of injury. Treat suspected inhalation injury prior to definitive diagnosis. Provide humidified oxygen (100%) by facemask. Obtain arterial blood gas con centrations, including carboxyhemoglobin levels. Control of the upper airway is achieved by prompt endotracheal intubation. Indications for intubation include (1) full-thickness burns of the face or perioral region, (2) circumferential neck burns, (3) acute respiratory distress, (4) progressive hoarseness or air hunger, (5) respiratory depression or altered mental status, and (6) supraglottic edema and inflammation on bronchoscopy. Additionally, consider the patient’s anticipated clinical course. BURN TREATMENT The management of patients with moderate to major burns can be divided into three phases: (1) prehospital care, (2) ED resuscitation and stabilization, and (3) admission or transfer to a specialized burn center. PREHOSPITAL CARE The basis of prehospital care of the burn-injured patient consists of the following: (1) stop the burning process; (2) assess and, if necessary, secure the airway; (3) initiate fluid resuscitation; (4) relieve pain; (5) protect the burn wound; and (6) transport the patient to an appropriate facility. On-site assessment of a burned patient is divided into primary and secondary surveys. In the primary survey, identify and treat immediately life-threatening conditions. Initial management of the burn-injured patient is similar to that of any other trauma patient: airway, breathing, circulation, and cervical spine immobilization where appropriate. Dur ing the secondary survey, perform a thorough head-to-toe evaluation. The patient must be extricated from the burning environment, and burning clothing must be immediately removed. The remainder of the clothing should be removed after the airway, breathing, and circulation are secured. Remove rings, watches, jewelry, and belts because they retain heat and produce a tourniquet-like effect on the extremity, caus ing ischemia. Give oxygen by facemask. Pay close attention to the air way: rapid deterioration may occur even when the initial assessment judges the airway to be acceptable. Consider prophylactic intubation in patients with perioral burns sustained in a closed-space fire. Give IV isotonic crystalloid. Cover the patient with clean sheets to protect the wound. While early cooling can reduce the depth of burn and reduce pain, uncontrolled cooling may result in hypothermia. Provide analgesia according to protocol or with direction of the online medical control physician. Transport the patient to the nearest ED capable of caring for a burn-injured patient or, if none is available, to the nearest ED for stabilization and subsequent transfer.
, uncontrolled cooling may result in hypothermia. Provide analgesia according to protocol or with direction of the online medical control physician. Transport the patient to the nearest ED capable of caring for a burn-injured patient or, if none is available, to the nearest ED for stabilization and subsequent transfer. ED MANAGEMENT INITIAL ASSESSMENT Obtain a directed history from the patient and EMS personnel to deter mine the burning agent(s), involvement of chemicals, the duration of exposure, and if the injury was sustained in an open or enclosed space. Assess for loss of consciousness, risk of blast injury from explosion, contact with electricity, or other trauma. Assess the adequacy of, or need for, cervical immobilization. Obtain the general history, including past medical and surgical illnesses, chronic disease, allergies, medications, and tetanus immunization status. Quickly assess the patient’s respiration and circulation and initiate stabilization (Table 217-5). Examine the patient for signs of inhalation injury, as evidenced by respiratory distress, facial burns, carbo naceous sputum, singed nasal hair, and soot in the mouth. If there is any evidence of airway compromise with swelling of the neck, burns inside the mouth, or wheezing, perform early endotracheal intubation. Assess the adequacy of circulation by noting the blood pressure, pulse rate, capillary refill time, mental status, and urinary output, keeping in mind that due to the catecholamine response associated with burn injury, a heart rate of 100 to 120 beats/min is considered within normal limits for adults. 10 Insert IV lines in unburned areas, but when this is not possible, a burned area can be used and resuscitation started according to a burn fluid resuscitation formula. During the secondary examination, perform a head-to-toe assess ment, including examination of the eye for corneal burns. Estimate and record the size and depth of the burn injury. In patients with partialthickness burns of >20% of body surface area, nasogastric tube inser tion is routinely required due to frequent development of ileus. Insert a urinary catheter to measure urinary output and to prevent urinary retention in patients with perineal burns. Tintinalli_Sec16_p1333-1418.indd 1388 8/2/19 8:23 PM
nts with partialthickness burns of >20% of body surface area, nasogastric tube inser tion is routinely required due to frequent development of ileus. Insert a urinary catheter to measure urinary output and to prevent urinary retention in patients with perineal burns. Tintinalli_Sec16_p1333-1418.indd 1388 8/2/19 8:23 PM CHAPTER 217: Thermal Burns 1389 TABLE 217-6 Parkland Formula for Fluid Resuscitation Adults • LR 4 mL × weight (kg) × % BSA burned* over initial 24 h • Half over the first 8 h from the time of burn • Other half over the subsequent 16 h • Example: 70-kg adult with 40% second- and third-degree burns: 4 mL × 70 kg × 40 = 11,200 mL over 24 h Children • LR 3 mL × weight (kg) × % BSA burned* over initial 24 h plus maintenance • Half over the first 8 h from the time of burn • Other half over the subsequent 16 h Abbreviations: BSA = body surface area; LR = lactated Ringer’s solution. *Partial- and full-thickness burns only. TABLE 217-5 ED Care of Patients With Major Burns Airway Breathing Circulation Adjuncts Reevaluation of airway Continuous pulse oximetry with supplemental oxygen Establishment of two large-bore peripheral IV lines in unburned skin Placement of Foley catheter Early intubation for any sign of breathing difficulty, airway burn, swelling, or suspected inhalation injury Insertion of nasogastric tube Determination of carboxyhemoglobin level IV administration of lactated Ringer’s solution using Parkland or other burn resuscitation formula Administration of tetanus booster Bronchoscopy if inhalation injury is a concern Cardiac monitoring Assessment for other trauma using Advanced Trauma Life Support guidelines Mechanical ventilation as needed Pain control Routine laboratory tests, including a CBC and measurement of elec trolyte, BUN, creatinine, and glucose levels, should be performed. In patients with moderate or severe burns or suspected inhalation injury, obtain an arterial blood gas analysis, carboxyhemoglobin level, serum creatine kinase, urinalysis for myoglobin, chest radiograph, and ECG. Fiberoptic bronchoscopy is indicated in suspected inhalation injury and in intubated patients for both diagnostic and therapeutic purposes. Additional radiographs should be taken as indicated for other suspected trauma. Treat suspected inhalation injury with humidified 100% oxygen, intubation and ventilation, bronchodilators, lung-protective vent settings, and aggressive pulmonary toilet; hyperbaric oxygen may be necessary for severe carbon monoxide poisoning. Burn injury in the pregnant woman is associated with significant morbidity to mother and child. The outcome of the pregnancy is deter mined by the extent of injury to the mother. Spontaneous termination of pregnancy is common in large–body surface area burns. Resuscitation requirements may exceed those estimated using common guidelines. Fetal monitoring and early consultation with the obstetrician and burn specialist are recommended. FLUID RESUSCITATION Although the importance of early fluid resuscitation is supported by clinical experience, 22,23 no consensus exists on the appropriate assessment of resuscitation and its effect on outcome. 22 Additionally, overresuscitation is not without consequence. In general, resuscitation should be guided by monitoring cardiorespiratory status and urine output rather than strict adherence to a formula. The following formulas are a guide for fluid resuscitation of the burn-injured patient. Monitor and adjust according to individual patient response. The Baxter or Parkland formula is likely the most widely used thermal injury resuscitation regimen in North America.
rine output rather than strict adherence to a formula. The following formulas are a guide for fluid resuscitation of the burn-injured patient. Monitor and adjust according to individual patient response. The Baxter or Parkland formula is likely the most widely used thermal injury resuscitation regimen in North America. 8,9 This formula calls for 4 mL of lactated Ringer’s solution multiplied by the percentage of body surface area burned (partial- and full-thickness burns only) multiplied by patient body weight in kilograms. Half of the total is administered in the first 8 hours after injury and the remainder during the following 16 hours (Table 217-6). Volumes may be large, and hemodynamic monitoring techniques should be used to protect against inadvertent volume overload. Patients with thermal injury and concomitant multisystem trauma and those with inhalation injuries generally require fluid resuscitation in excess of calculated needs. Burn patients with preexisting cardiac or pulmonary disease require much greater attention to fluid management. Monitor fluid resuscitation closely by frequent assessment of vital signs, cerebral and skin perfusion, pulmonary status, and urinary output, as well as hemodynamic monitoring. Urine output should be 0.5 to 1.0 mL/kg/h. Because the ED is primarily responsible for initial fluid resuscitation, early discussion with burn specialists may be helpful in avoiding underor overresuscitation. Patients with major burns can quickly receive excessive IV fluid during the prehospital and ED phases, particularly if two large-bore peripheral catheters are in place with fluid infusing at a wide-open rate. Document total fluid infused and titrate infusion to the patient’s response. Clear documentation of fluid resuscitation should accompany all patients transferred to burn centers. There are several methods of calculating fluid resuscitation for infants and children. The Parkland formula can be modified to maintain a uri nary output of 1 mL/kg/h. Alternatively, a pediatric maintenance rate for 24 hours can be calculated, and an additional 2 to 4 mL/kg multiplied by percentage of body surface area burned is then added to the total. The entire amount is infused over the first 24 hours. In children weighing <25 kg, a goal urine output of 1.0 mL/kg/h is necessary. Add 5% dextrose to maintenance fluids for children weighing <20 kg due to smaller glycogen stores. Two additions or modifications to isotonic crystalloid resuscitation have been studied: adjuvant colloid and hypertonic saline. However, neither improves patient outcome. Adjuvant colloid given along with isotonic crystalloid resuscitation is not beneficial and is associated with decreased glomerular filtration rate. 24 Discussion of the use of adjuvant colloid continues, but it is used very little in North America and the United Kingdom, 25 although Israeli investigators have reported favor able results with the addition of colloid to their burn formulas. 26 Use of hypertonic saline has been associated with an increased rate of renal failure and death. 27 In an effort to decrease burn edema, protein loss, and abdominal compartment syndrome, investigators have also studied the efficacy of permissive hypovolemia in reducing burn edema and the multiple organ dysfunction that follows. 28 This practice necessitates invasive monitoring and is of interest, but it is not standard of care and should not be used in ED resuscitation at this time. Electrical injuries, incineration burns, and associated crush injuries may produce rhabdomyolysis and myoglobinuria, leading to renal failure. Acute renal failure occurs in approximately 15% of patients admitted to burn centers and is associated with severe burns (mean body surface area involvement of 48%).
this time. Electrical injuries, incineration burns, and associated crush injuries may produce rhabdomyolysis and myoglobinuria, leading to renal failure. Acute renal failure occurs in approximately 15% of patients admitted to burn centers and is associated with severe burns (mean body surface area involvement of 48%). 29 Therapy to limit renal dam age from myoglobinuria should be initiated as outlined in Chapter 89, “Rhabdomyolysis. ” WOUND CARE After evaluation and resuscitation of the patient, attend to burn wounds. 2 Initially, wounds are best covered with a clean, dry sheet. Later, small burns can be covered with a moist saline-soaked dressing while the patient is awaiting admission or transfer. The soothing effect of cooling on burns is most likely due to local vasoconstriction. Cooling stabilizes mast cells and reduces histamine release, kinin formation, and thromboxane B 2 production. For large burns, sterile drapes are Tintinalli_Sec16_p1333-1418.indd 1389 8/2/19 8:23 PM
is awaiting admission or transfer. The soothing effect of cooling on burns is most likely due to local vasoconstriction. Cooling stabilizes mast cells and reduces histamine release, kinin formation, and thromboxane B 2 production. For large burns, sterile drapes are Tintinalli_Sec16_p1333-1418.indd 1389 8/2/19 8:23 PM 1390 SECTION 16: Environmental Injuries FIGURE 217-8. Escharotomy of the hand. FIGURE 217-9. Escharotomy of the chest wall. TABLE 217-7 ED Care of Minor Burns • Provide appropriate analgesics before burn care and for outpatient use • Cleanse burn with mild soap and water or dilute antiseptic solution • Debride wound as needed • *Apply topical antimicrobial agent or dressing: • Bacitracin ointment • Triple-antibiotic ointment (neomycin, polymyxin B, bacitracin zinc) • Consider use of synthetic, solid, or biological dressings • Provide detailed burn care instructions with follow-up in 24–48 h *Consider contacting the director of the local or regional burn center to identify the center's preferred topical antimicrobial agent and/or synthetic occlusive dressing to integrate local and tertiary burn care. preferred, because application of saline-soaked dressings to a large area can cause hypothermia. Consult the admitting service or burn center early. Avoid the use of antiseptic dressings in the ED, because the admitting service will need to assess the wound. Wound care for transferred patients should be discussed with the accepting burn center. Do not delay transfer for wound debridement. For transferred patients, the referring facility should follow the accepting regional burn center’s treatment protocol if available. Escharotomy Patients with circumferential deep burns of the limbs may develop compromise of the distal circulation, particularly after initiation of resuscitation. The distal vascular status of such patients must be monitored closely, including pulses, capillary refill, pulse oximetry, and skin temperature. Doppler flow testing may likewise be useful. If vascular compromise is evident, escharotomy is indicated. The eschar is incised with a scalpel to the level of the fat on the mid-lateral portion of the limb, using care to avoid incising the fascia (i.e., fasciotomy). Elevated compartment pressures can be clinically evident. The incision may be extended to the hand and fingers ( Figure 217-8). Escharotomy may provoke substantial soft tissue bleeding. Consider consultation by phone with a burn surgeon. If there are circumferential burns of the chest and neck, eschar may restrict ventilation. An escharotomy of the chest wall should be per formed to allow adequate ventilation. Incisions are made at the anterior axillary line from the level of the second rib to the level of the twelfth rib. These two incisions should be joined transversely so the chest wall can expand (Figure 217-9). PAIN CONTROL Burn injuries are exceedingly painful, and superficial partial-thickness burns are the most painful. Burn injury not only makes an otherwise already injured area and surrounding tissue more painful, but also causes hyperalgesia, chiefly mediated by A fibers. Local cooling may be soothing but does not provide pain control and can cause hypothermia; additional pain management should be provided. During the acute phase, the preferred route for most medication is IV . Opioids (e.g., morphine, fentanyl, hydromorphone) are the mainstay of treatment, and relatively large dosages may be required. Anxiolytic agents may also be given. Ensure adequate analgesia for patients being discharged. Achieving adequate pain control is required for patients being considered for discharge. CARE OF MINOR BURNS Minor burns typically qualify for ambulatory care.
instay of treatment, and relatively large dosages may be required. Anxiolytic agents may also be given. Ensure adequate analgesia for patients being discharged. Achieving adequate pain control is required for patients being considered for discharge. CARE OF MINOR BURNS Minor burns typically qualify for ambulatory care. Minor burns should be isolated, should not cross joints or be circumferential, and should not meet criteria for burn center care. Treatment of minor burns is provided in Table 217-7. Even in patients with burn injury <10% of body surface area, patients at the extremes of age and/or patients with significant comorbidities, challenging social situations, or inadequate pain control may require inpatient care and possibly transfer to a burn center. Care of minor burns in discharged patients requires appropriate wound care instructions, adequate pain control, and coordination between the ED and the physician who will see the patient in follow-up. Because burns are painful, appropriate analgesia is required. After appropriate analgesia, clean the burn wound with mild soap and water or dilute antiseptic solution. Debride ruptured blisters. Also debride large intact blisters or those over very mobile joints. Small blisters on nonmobile areas should be left intact. Tetanus immunization status should be assessed, and tetanus toxoid and/or immunoglobulin should be administered as needed. Topical antimicrobials (antiseptics or antibiotics) play an important role in reducing bacterial colonization and enhancing the rate of healing in burns. 8,9 A wide variety of topical agents and specialized dressings are commonly used for minor burns. A mainstay of treatment has traditionally been 1% silver sulfadiazine due to its easy application and minimal toxicity. However, three meta-analyses found delayed healing in burns treated with silver sulfadiazine compared to newer dressings. 32-34 Newer dressings require less frequent dressing changes and are associated with reduced pain. 32 Do not use silver sulfadiazine on the face because it can stain the skin gray. Silver sulfadiazine should not be used in infants less than 2 months of age. For the face or other small minor burns, recommended topical agents include bacitracin and triple-antibiotic (neomycin, polymyxin B, and bacitracin zinc) ointments. 31 Although 8.5% mafenide acetate cream and 0.2% nitrofurazone ointment are available for topical application, these are not good choices for treatment of large burns in an outpatient setting. Mafenide penetrates the eschar well and is useful in treating patients with invasive infections, but it is a carbonic anhydrase inhibi tor and can cause metabolic acidosis. Nitrofurazone is supplied in a polyethylene glycol vehicle that can be toxic if absorbed in patients with Tintinalli_Sec16_p1333-1418.indd 1390 8/2/19 8:23 PM