1348 SECTION XII Pediatric Critical Care Environmental Injury and Trauma Scald Burn Scald is a frequent mechanism of burn An analysis of 127,016 patients who were hospitalized in US burn centers showe[.]
1348 S E C T I O N X I I Pediatric Critical Care: Environmental Injury and Trauma Scald Burn Scald is a frequent mechanism of burn An analysis of 127,016 patients who were hospitalized in US burn centers showed that approximately 30% were due to scald burns.1 The majority of scald injuries result from domestic accidents and are potentially preventable (e.g., spilling or splashing hot water).22 Infants and toddlers have a higher incidence of scald burns compared with older children.1,23 In low-income countries, this is mainly due to unsafe and open cooking.24 Scald injuries are commonly associated with the preparation or consumption of food.25,26 Accidental hot liquid spills account for many of these injuries; a thorough history of the patient at admission should include the type and consistency of the causative liquid Compared with water and thin liquids, oil and thick soups have a higher heat capacity and are more viscous This may translate into longer contact time and higher temperatures, causing greater skin and soft tissue damage In general, water heated to a temperature of 60°C (140°F) will cause a deep burn after seconds of contact; water heated to 68°C (155°F) will cause the same burn after second of contact.27 Scald burns are more likely to be associated with child abuse than other types of burn injuries.28 Classic scald patterns consistent with child abuse include glove-like or stocking-like burns to the hands or feet and/or symmetric burns to the buttocks, legs, or perineum Concomitant injuries (including bruising, fractures, and retinal hemorrhages) and delays in seeking treatment and/or inconsistencies in the patient history should trigger concern These scenarios must prompt a full evaluation by social services with a referral to the appropriate state or government agencies regardless of the depth or extent of the burn Electrical Burn Electrical injuries accounted for less than 5% of all admission to US burn centers in 2016.1 The prevalence in low-income countries is up to 20% of all burns.29–31 Electrical burns are accompanied by a higher overall morbidity and mortality than flame or scald burns.29,32 The majority of injuries involve electrical cords and outlets, with rare cases from lightning Most homes in the United States use alternating current (AC) Although more efficient than direct current (DC), AC is more dangerous.33 Tissue damage typically results from heat generated by tissue resistance to current flow Thus, the determinants of injury are voltage, tissue resistance, and time of contact to the body.34 Young males are affected more often than their female counterparts (80%), and electrical injuries often occur at work (.90% in adults).35 Also, children are generally more susceptible to electrical injuries owing to their propensity to chew on cords or insert objects into outlets Many of those burns are so-called “balcony injuries” that mainly occur owing to poor safety standards in low-income countries.36 Wet or moist skin, including the mucous membranes around the mouth, has low resistance and permits electrical current entry These injuries often result in considerable soft tissue trauma Nerves, blood vessels, and muscles exhibit the least resistance as compared with bone, fat, and tendons Higher-resistance tissues tend to heat and cause damage nearby, especially when no adjacent lower-resistance pathway is available (wrists and ankles).37 The lack of overt skin damage may mask more significant underlying soft tissue damage This leads to a significantly higher rate of major amputations compared with nonelectrical burns.38 Patients with electrical injuries are more prone to complications, such as neurologic symptoms or compartment syndrome.39 Cardiac arrhythmias occasionally are seen after burn injury, usually atrial tachycardia or atrial fibrillation In some cases, the electrical injury may unmask an accessory pathway, resulting in a postelectrical injury reentry tachycardia.37 Cataracts are an additional complication of some electrical burn injuries; these may be noted prior to discharge on dilated eye examination or within 24 months of the electrical injury.40 Chemical Burn Chemical burns are less common, representing only 3% of admissions to burn centers in the United States.1,41 These result from contact with acid, alkali, or organic compounds, with acids being the most frequent agents.42 In 2017, the National Poison Data System reported more than 2.6 million poison exposures in the United States Children younger than years were involved in 35.5% of poison exposures, and children younger than years accounted for approximately half of all exposures to poison (48.0%).43 Household cleaning substances account for one of the top five common exposures in children years or younger This includes alkali drain cleaners, which are composed of sodium hydroxide; they can cause significant tissue injury from interaction with cutaneous lipids in the skin Other common exposures in this age group were cosmetic/personal care products, analgesics, foreign bodies/toys and topical preparations.43 The severity of injury is determined by not only the type and concentration of the chemical but also the duration of exposure.44 The appropriate treatment of chemical burns does not involve neutralization of the acid or base since the resultant exothermic reaction would worsen tissue injury Instead, the initial treatment of chemical burns includes copious irrigation with tepid water for at least 15 minutes Hydrofluoric (HF) acid burns represent a distinct clinical scenario.45 Stuke et al reported that 17% of 35 patients admitted to their burn unit in a 15-year interval were exposed to HF acid.46 In addition to being a corrosive agent, fluoride causes severe, deep liquefaction necrosis.47 Copious irrigation will attenuate the initial chemical burn, but neutralization with calcium or magnesium is occasionally necessary to halt further necrosis Current HF acid treatment recommendations include topical calcium and close monitoring of serum calcium levels (with supplementation as needed).48 Cardiac arrhythmias resulting from calcium sequestration are common with significant HF acid exposures and are typically treated with parenteral calcium.49 Normal Skin Anatomy In addition to being the major barrier of protection from fluid loss, mechanical damage, and entrance of infectious agents, the skin is the biggest human organ and plays an important role in thermoregulation Skin contact also provides important information about the environment through touch, and skin appearance is one of the major determinants of identity and body image.50,51 Divided into five distinct layers (stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum), the epidermis consists of keratinocytes, melanocytes, and Langerhans cells, all with barrier function (Fig 116.1).52 The dermis consists of structural proteins and cells responsible for tensile strength.47 Additional appendages—including blood vessels, hair follicles, and sweat glands—are rooted in the dermis CHAPTER 116 Burn and Inhalation Injury Epidermis 1st degree Dermis 2nd degree 1349 Subcutaneous 3rd degree layer Muscle 4th degree • Fig 116.1 Cross-sectional representation of normal layers of skin and subcutaneous tissue (left) and representative degrees of burn injury based on depth of burn (right) (From Shiland B Mastering Health Care Terminology 2nd ed St Louis: Elsevier; 2006.) and are responsible for the regeneration of epidermal cells after superficial injury.18 Assessment of burn depth is vital since deeper burns destroy these dermal appendages Without skin grafting, deep burn wounds heal from the margins of injury, resulting in prolonged open areas, wound infection, and debilitating scars and contractures dermal-epidermal junction After debridement, the underlying dermis is erythematous, appears wet, is painful, and blanches with pressure As the deeper dermis is left undamaged, wounds heal within weeks without the need for skin grafting, typically without hypertrophic scarring (although there may be long-term pigment changes).18 Depth and Size of Burn Deep Partial-Thickness Burns Burns can affect one or both layers of the skin and may also extend to subcutaneous fat, muscle and/or bones.53 Various modalities— such as photometry, thermography, pulse-echo ultrasound, or serial tissue biopsies—have been investigated in order to find a more accurate method for measuring burn depth Both superficial and deep partial-thickness burns have traditionally been classified as second-degree burns These two categories merit distinction as deep partial-thickness burns behave clinically similarly to third-degree burns Deep partial-thickness burns blister, but as tissue damage extends deep into the dermis, the blister base may appear to have a mottled pink and white appearance The blood vessels of the dermis are partially damaged, giving rise to variance in discoloration of the wound base These wounds are less painful than superficial burns owing to nerve injury and because the capillaries refill slowly when pressure is applied Treatment of these wounds customarily requires excision and grafting when not expected to heal within weeks Decisions on the actual burn depth can usually be made when the dynamic process of burn evolution peaks at days after injury.51 Some burn surgeons advocate initial monitoring for up to 14 days to allow for demarcation Serial clinical examinations for partial thickness scald burns for 14 days have been shown to either reduce the excision area or avoid surgery altogether.54 Rarely, these wounds will heal without surgical intervention but will remain at risk for developing hypertrophic burn scars and/or contractures.18 Superficial Burns Traditionally, depth has been categorized as either first-, second-, third-, or fourth-degree burn First-degree (superficial burns) are erythematous and usually very painful but not form blisters Traditionally, most sunburns can be classified as superficial burns Damage is isolated to part of the epidermis only, sparing the dermis and dermal structures These burns blanch easily on examination and heal within to days after the damaged epidermis desquamates and is replaced by regenerating keratinocytes The wounds usually heal without scarring, and surgical treatment is not needed.18 Superficial burns are neither included in calculations of the burn size nor in estimates for the need of fluid demands Superficial Partial-Thickness Burns Superficial partial-thickness burn wounds differ from first-degree burns in that the entire epidermis and superficial dermis is injured These burns typically form fluid-containing blisters at the Full-Thickness Burns Full-thickness burns are synonymous with third-degree injuries and involve all skin layers These wounds need definitive surgical 1350 S E C T I O N X I I Pediatric Critical Care: Environmental Injury and Trauma treatment in order to heal On examination, these wounds are white, cherry red, brown, or black in color and not blanch with pressure The burned areas are dry, charred, and often leathery compared with unburned skin Wounds are typically insensate because of the superficial nerve injury In some cases, fullthickness burns may appear translucent, with clotted vessels shining through them Early excision and grafting are needed to reduce rates of infection and hypertrophic scarring Immersion scald burns that have full-thickness depth can sometimes be confused with partial-thickness burns owing to their red color Fourth-degree burns are full-thickness injuries involving the underlying subcutaneous fat, muscle, and tendons These injuries are more commonly associated with limb loss and/ or need for extensive reconstruction in addition to grafting.18 Zones of Injury Burn wounds continue to evolve for days after the initial injury; the subsequent inflammatory process may last for several months.55,56 The wound is divided into three zones of injury: zone of coagulation, zone of stasis, and zone of hyperemia The zone of coagulation is easily identified, as it comprises the necrotic tissues closest to the injury site The zone of hyperemia consists of normal, uninjured skin with a physiologic increase of blood flow in response to local tissue injury The zone of stasis is located between the zones of coagulation and hyperemia, representing an area of ongoing injury.18 Poor perfusion of this zone can result in the progression of initially viable tissue, which furthers necrosis and deepens wounds Tobalem et al.57 used a rat burn model to demonstrate that early erythropoietin administration prevented burn progression, mainly by improving vascular perfusion Although this is not currently used for the treatment of pediatric burns, current research is targeting new methods to salvage these zones of intermediate injury.58 Estimating the Extent of the Burn An accurate assessment of both the extent and depth of the burn is necessary to guide initial care The percent of TBSA burned is an independent risk factor that correlates with length of hospital stay and mortality in pediatric burns.19 However, the extent of burn injuries may be overestimated up to 75% by the initial care provider.59 This results in over-resuscitation with potentially devastating complications and poor use of limited resources (e.g., inappropriate transfer to burn centers).60 Future methods to accurately calculate TBSA burn include using computerized imaging, two- and three-dimensional graphics, and body contour reproductions.61 Current methods of calculating combined second- and thirddegree burn size in adults include burn diagrams, the “rule of nines,” and a general estimate that the palm and fingers of one hand account for 1% of the normal BSA.62 Palaski and Tennison developed the rule of nines, which is a rough estimation of adult BSA divided into multiples of 9%.61 This calculation rarely underestimates TBSA but often overestimates it, especially in children.61 BSA is distributed differently in children and infants owing to proportionally larger heads and smaller extremities This supports the need for age-specific surface area charts, such as the Lund-Browder diagram, to better estimate the extent of burns in children (Fig 116.2) Additionally, the rule of nines, which is currently the most commonly used method, may not be accurate in overweight patients Williams and Wohlgemuth suggest the “rule of sevens,” which includes a higher trunk proportion.63 There is also growing interest in the application of the software BurnCase 3D (RISC Software) in burn centers, which considers the body mass index (BMI).64 Prehospital and Early Management Burn care by first responders can broadly influence the outcome of severely burned patients The aim of prehospital management should be to minimize the effects of the injury and to prevent the severity of secondary injuries Successful management of the severely burned patient begins at the scene of injury and continues in the emergency department with a thorough Advanced Trauma Life Support (ATLS) trauma assessment as well as the American Burn Association’s Advanced Burn Life Support (ABLS) assessment.65,66 Prior to specific treatment, patients must be removed from the thermal source of injury in order to stop the burning process, and burns should be washed with tepid water Excessive cooling can lead to a significant drop in body temperature.66,67 Ice or iced water has been shown in animal studies to increase tissue damage and mortality Also, it should not be used given the added risk of hypothermia in patients with more extensive burns.68,69 Prehospital care of wounds is simple, focusing on protection from the environment by applying clean/sterile dressings Lau et al reported that the prompt removal of clothes following scald burns significantly reduced mortality and morbidity.70 Chemical burns from liquid chemicals should be flushed copiously with water to remove the inciting agent and to prevent further tissue damage Dry chemicals should be brushed off before any irrigation Approximately 10% of all burn patients present with additional traumatic injuries The primary caregiver should not be distracted by the obvious external burn injury when performing the rapid trauma evaluation.18 Patients with severe burn shock or trauma are at risk for loss of airway due to altered mental status or to supraglottic obstruction from edema.71 Initiation of resuscitation is reserved for infants and children with 10% or greater TBSA burns, for teenagers with 15% or greater TBSA burns, and for industrial and high-voltage electrical burns Electrical injuries require specific evaluation (e.g., repeated electrocardiography and continuous clinical monitoring) given the propensity for compartment syndromes and multiorgan system involvement Cardiac dysrhythmias and direct muscle necrosis can develop with high-voltage electrical burns, requiring intervention or prolonged cardiac monitoring.37 Seizures and spinal cord transection-like injuries are possible with electrical burns, as is respiratory arrest secondary to injury of the brainstem or to tetany of the respiratory musculature.37 After complete primary and secondary surveys, attention should turn to evaluation and management of the burn injury Using appropriate tools such as the Lund-Browder chart, the depth and extent of burn should be assessed and used to guide further care Approximately 60% to 70% of burns seen in emergency departments involve less than 10% TBSA.72 The majority of these burns can be treated safely with minor debridement, oral hydration, topical wound care, and outpatient follow-up Those patients requiring supplemental nutrition or hydration, or those who not respond outpatient treatment, may need continued care in an inpatient setting In adults with more than 20% TBSA involvement, in infants with more than 10% TBSA involvement, or in cases with a suspicion of inhalation injury, inpatient treatment with intravenous (IV) resuscitation and potential transfer to a burn center should be strongly considered CHAPTER 116 Burn and Inhalation Injury 1351 Burn Estimate and Diagram Age vs Area Areas treated at SHC Cause of injury: Chemical Contact Electrical Flame Inhalation Scald Other: Initial burn diagram Color code Red-3° Blue-2° Grafted Temporary wound coverage Final burn diagram Color code Red-3° Blue-2° Date of burn: Time of burn: Height (cm): Weight (kg): Signature Date Signature Area Birth yr 1–4 yrs 5–9 yrs 10–14 yrs 15 yrs Adult Head Neck Ant trunk Post trunk R Buttock L Buttock Genitalia R.U arm L.U arm R.L arm L.L arm R hand L hand R thigh L thigh R leg L leg R foot L foot 19 13 13 2.5 2.5 4 3 2.5 2.5 5.5 5.5 5 3.5 3.5 17 13 13 2.5 2.5 4 3 2.5 2.5 6.5 6.5 5 3.5 3.5 13 13 13 2.5 2.5 4 3 2.5 2.5 8 5.5 5.5 3.5 3.5 11 13 13 2.5 2.5 4 3 2.5 2.5 8.5 8.5 6 3.5 3.5 13 13 2.5 2.5 4 3 2.5 2.5 9 6.5 6.5 3.5 3.5 13 13 2.5 2.5 4 3 2.5 2.5 9.5 9.5 7 3.5 3.5 Initial TBSA 2° 3° Total Date Potential Donor site Final TBSA 2° 3° Total Graft size Total: • Fig 116.2 Shriners Hospitals for Children diagram used for estimation of burn depth and extent in pediatric burned patients Transfer to Burn Centers The optimal treatment and management of large or complicated burn injuries is in a high-volume burn center with a multidisciplinary team, including burn surgeons and nurses, physical and occupational therapists, dietitians, psychiatrists, respiratory therapists, and social service support staff.73 Rapid, uncontrolled transport of burn patients is not the highest priority if no other life-threatening injuries are present Current American Burn Association guidelines recommend the transfer of patients with severe injuries or those meeting specific criteria to dedicated burn centers74 (Box 116.1) Before transfer, airway assessment and protection, initiation of resuscitation, and evaluation for coexisting injuries should be performed.65 Inhalation injury may go unrecognized at the initial assessment Clinical signs of potential inhalation injury include facial burns, singed nasal hairs, carbonaceous sputum, hypoxia, and history of entrapment in an enclosed space The presence of airway injury, signs of airway obstruction, and the presence of preexisting airway abnormality should be assessed as soon as the patient arrives at the burn center.65 Subsequently, the burn wounds should be covered with clean, dry material or with nonadherent gauze.75 The use of wet dressings should be avoided to prevent development of hypothermia and subsequent complications in patients with large burn wounds.73 Keeping the patient warm and dry is crucial for severely burned patients since the protective role of skin is impaired Tetanus prophylaxis should be administered along with appropriate pain control before transport In patients with extensive burns, a Foley catheter should be inserted to help guide fluid management It was reported that increased ambient room temperature can help to prevent hypothermia and reduce the burn patient’s stress response.76 1352 S E C T I O N X I I Pediatric Critical Care: Environmental Injury and Trauma • BOX 116.1 American Burn Association Criteria for Burn Center Referral • Partial- and full-thickness burns 10% of total burn surface area in patients ,10 years or 50 years • Partial- and full-thickness burns 20% of total burn surface area in patients in other age groups • Partial- and full-thickness burns involving face, hands, feet, genitalia, perineum, or major joints • Electrical burns • Chemical burns • Inhalation injury • Burn injury in patients with preexisting medical disorders (e.g., coronary artery disease or lung disease) that could complicate management, prolong recovery, or increase mortality rate • Any burn with concomitant trauma in which the burn injury poses the greatest risk • Burn injury in children admitted to hospitals without qualified personnel or equipment for pediatric care • Burn injury in patients requiring special social, emotional, or rehabilitative support, including cases of child abuse Data from American Burn Association Burn Center Referral Criteria http://ameriburn.org/wp-content/ uploads/2017/05/burncenterreferralcriteria.pdf Pain Management The severity of the burn determines the degree of pain experienced by burn patients In general, medications for pain relief should not be given intramuscularly (IM) or subcutaneously (SQ) Mild pain can be treated with acetaminophen 650 mg orally every to hours Severe pain usually requires morphine (1–4 mg IV every 2–4 hours), but meperidine (Demerol, 10–40 mg IV every 2–4 hours) can also be given.77 Tetanus prophylaxis needs to be administered based on the patient’s immunization status A 0.5-mL boost of tetanus toxoid should be given to all burn patients If prior immunization is absent or unclear, or if the last booster was more than 10 years ago, 250 U of tetanus immunoglobulin is also indicated.77 Resuscitation Sufficient resuscitation is an immense challenge in the initial phase following severe burn.78 The first 48 hours of treating pediatric burn patients are the most critical owing to their risk of burn-induced hypovolemic shock.66 The ability to effectively resuscitate is critical to outcome, because sufficient reconstitution of intravascular volume and maintenance of end-organ perfusion is needed.79,80 Delayed initiation of resuscitation of more than hours after admission has been shown to significantly increase mortality following severe burn injury in children.19 In patients with burn greater than 10% TBSA, adequate IV access should be obtained via peripheral and/or central lines In severe burn injuries (greater than 40% TBSA), if central or peripheral IV access cannot be obtained in a timely manner, intraosseous (IO) cannulation should be considered Infusion of a balanced crystalloid solution should be started as soon as IV access is obtained (if possible, already by the first responders), with the infusion rate titrated after full assessment of burn injury Initial resuscitation guidelines have historically followed one of two formulas: the Parkland formula81 or the modified Brooke formula.82 These formulas serve only as guidelines Resuscitation must be tailored to each individual patient with the goal of restoring and maintaining perfusion without inducing fluid overload The Parkland formula was developed in 1968 by Baxter and Shires, originating from 30% to 50% TBSA flame burn experiments in dogs.81 They found that resuscitating with a higher volume in the first hours improved cardiac output, which could be maintained over the next 16 hours with lower fluid rates On the basis of these studies, recommendations for resuscitation of large burns using the Parkland formula were extrapolated.83 This formula recommends the total administration of mL/kg per % TBSA burn over the first 24 hours postinjury One-half of this volume is administered during the first hours, with the remaining volume delivered during the next 16 hours The Parkland formula also provides for colloid administration via 25% albumin on the second day postburn Although the Parkland formula is the most widely used resuscitation formula, it is closely followed by the modified Brooke formula On the basis of the work done at the Brooke Army Medical Center, Pruitt altered the original Brooke formula,84 which recommended 1.5 mL/kg per % TBSA burn of crystalloid and 0.5 mL/kg per % TBSA burn of colloid This group demonstrated that a lower volume of fluid could achieve the same end points of resuscitation as the Parkland formula.83 The modified Brooke formula calls for mL/kg per % TBSA burn of balanced salt solution over the first 24 hours after injury and no colloids Although both formulas call for the titration of fluid rates, in a comparative analysis, the Parkland formula more often resulted in over-resuscitation, proving to be an independent risk factor for mortality.85 A separate comparative study found no clinical differences in outcomes between patients resuscitated using these two formulas.86 Consensus fluid resuscitation by standardized formula has not been reached.83 However, efforts are being made to develop tools for accurate real-time monitoring of hemodynamic parameters and fluid resuscitation.87 In burn children, resuscitation strategies should include the administration of estimated basal fluid requirements in addition to the replacement of extensive fluid losses secondary to burn injury Pruitt initially coined the term “fluid creep” to describe the insidious increase in the volume of fluid that burn centers administer in the first 24 to 48 hours postburn in a well-meaning effort to avoid the onset of early acute kidney injury Several case series have been published, but the incidence remains unknown.88 Salinas et al reported on a fluid response– based model that is based on fluid infusion rates and urinary output.89 These data were implemented in a computerized openloop algorithm and computer decision support system Patients in the implementation of this system had improved fluid management during the ICU stay.89 In a porcine burn model, colonic fluid resuscitation was shown to be feasible to restore hemodynamic stability However, this approach was not yet been shown in humans.90 In children, the Cincinnati91 or Galveston92 formulas are the most commonly used (Table 116.1) All formulas rely on the accurate assessment of extent and depth of burn in order to provide appropriate resuscitation Fluid requirements should be titrated for clinical end points, including urine output of 0.5 to 1.0 mL/kg per hour in children85 and restoration of appropriate hemodynamic parameters (such as cardiac and urine output).83 Swords et al demonstrated that 50% of burns, in addition to nearly 20% of children who arrived at a burn center without a TBSA burn estimation, were overestimated by at least 5%.93 To avoid the complications of excessive or inadequate resuscitation (burn size is often overestimated), current ... partial-thickness burns have traditionally been classified as second-degree burns These two categories merit distinction as deep partial-thickness burns behave clinically similarly to third-degree... injured These burns typically form fluid-containing blisters at the Full-Thickness Burns Full-thickness burns are synonymous with third-degree injuries and involve all skin layers These wounds need... Immersion scald burns that have full-thickness depth can sometimes be confused with partial-thickness burns owing to their red color Fourth-degree burns are full-thickness injuries involving the