Introduction

The incidence of burn injuries has declined steadily over the past two decades. Approximately 1.25 million people are burned in the United States every year, of which one-third are children;¹ 60 000–80 000 patients sustain severe enough burns to require hospital admission;² 30 000 children require hospital admission for treatment of their burn injuries.¹ About 4000 burn patients die each year,² and approximately 1000 of them are children.³

House fires injure or kill over 10 000 people per year. House fires are among the leading causes of burn-related deaths in children. Children between 0 and 5 years of age are at a greater risk, as a disproportionate number of fire deaths occur in homes. Deaths among preschool children are at a rate of more that twice the national average (29.6 deaths/million children), or an average of 20% of the total percentage of all home fire deaths.

Scalds are common in children less than 3 years old. Scald injuries may be due to household accidents or deliberate abuse. These may include spilling hot coffee or water, children reaching up to countertops, pulling pot handles or cords attached to cooking appliances and spilling the contents onto themselves, unknowingly putting body parts under a hot water faucet or climbing into a hot tub, and intentionally or unintentionally being placed into or brought in contact with a hot substance by another individual.

Improvements have been made in the reduction of morbidity and mortality related to burns over the past few decades. Advances in fluid resuscitation, early surgical excision and grafting of the burn wound, infection control, treatment of inhalation injury, nutritional support, and support of hypermetabolic response to burns have contributed to a 50% decline in burn-related deaths and hospital admissions in the United States.² This overall improvement in mortality is most perceptible in children. In 1949, Bull and Fisher reported the expected 50% mortality rate for 49% total body surface area (TBSA) burn in children aged 0–14.⁴ This has improved to 50% expected mortality in 98% TBSA burn in the same population group.⁵

In a review of 103 children with >80% TBSA burns over a 15-year period, it was found that 69 patients survived, with an overall mortality of 33%. Mortality was greatest in children under 2 years of age and in burns >95% TBSA (Figs 35.1 and 35.2).⁶ Another major predictor of mortality was the length of delay to intravenous (IV) access (Fig. 35.3). Patients that received resuscitation fluids within the first hour had a significantly higher chance of survival.⁶ The mortality rate also increased significantly with inhalation injury, sepsis and multiorgan failure. In no pediatric patient, no matter how large the burn, how young, or with what type of inhalation injury, could it be accurately predicted at the time of admission whether they would live or die.⁶

Figure 35.1 Mortality in burns >80% total body surface area for various ages.

Figure 35.2 Mortality for increasing burn size.

Figure 35.3 Time to intravenous access in survivors and non-survivors. Mortality increases with delays in starting an intravenous line and instituting volume resuscitation.

The burn injury produces overwhelming physiological and psychological challenges to a child. The unique anatomical and physiological attributes of the child require the attention of physicians who are trained not only in burn care but also in the specifics of pediatric care. The most obvious differences between adults and children are size and body proportions. Shorter lengths, tighter angles, and smaller diameters of various anatomical structures and spaces make certain manipulations more difficult. These differences require the provision of special equipment and supplies, which reflect the configurations of pediatric anatomy. In addition to anatomical differences there are also many physiological differences between children and adults, which must be considered and will be discussed concerning the treatment of the pediatric burn patient.

Initial evaluation

A patient must be immediately removed from the source of burn, and clothing and jewelry removed immediately as these items can prolong the burning process. Pouring cool water onto the burn can cause hypothermia in large burns and should be avoided. After the burning process is stopped, the patient should be kept warm by covering with a sterile (if available) or clean sheet or blanket. If the burn is chemical, the patient should be removed from the chemical immediately and the burn wound should be irrigated with copious amount of water for at least 30 minutes. If chemical is powder, it should be brushed off first prior to irrigation.

Burn patients should be treated as a trauma patient and any potential life-threatening injuries should be identified and treated. The airway should be assessed first. Oxygen 100% should be administered and oxygen saturation monitored using pulse oximetry. If inhalation injury is suspected, arterial blood gas and carboxyhemoglobin levels should be obtained, as pulse oximetry readings will be falsely normal in patients with elevated carboxyhemoglobin levels, as carboxyhemoglobin is read as oxyhemoglobin by the pulse oximeter.

Tachypnea, stridor, and hoarseness indicate an impending airway problem due to inhalation injury or edema, and immediate intubation should be considered. A full-thickness circumferential chest burn can interfere with ventilation. Chest expansion should be observed to ensure adequate air movement. If the patient is on a ventilator, airway pressure and Pco₂ should be monitored. If ventilation is compromised, escharotomy of the chest should be performed to improve ventilation.

A blood pressure measurement may be difficult in patients with burned extremities. These patients may need an arterial line to monitor their blood pressure, especially if they require a long transfer to a burn center. A radial arterial line may not be reliable in pediatric patients with extremity burns and may be difficult to secure. A femoral arterial line may be more reliable and easier to secure.

A bladder drainage catheter is placed to monitor urine output as a measure of successful resuscitation. A nasogastric tube is placed in all patients with major burns, as they can develop gastric distension or ileus.

Persistent tachycardia should alert a clinician to a missed injury or under-resuscitation. Accurate and rapid determination of burn size and depth is vital to the proper management of burn injury.

Resuscitation

There is a systemic capillary leak after a large burn, which increases with burn size. Capillary usually regains competence 18–24 hours after burn injury. IV access should be established immediately for the administration of resuscitative fluid. Increased delays to commencement of resuscitation of burned patients result in worse outcomes and should be avoided.⁶ Therefore it is crucial that IV access be obtained as early as possible, even though such access may be difficult to obtain. Owing to the small circulating volume in children, delays in resuscitation for periods as short as 30 minutes can result in profound shock. Peripheral IV access is preferred, and it may go through burned skin if necessary. IV access should be well secured. When peripheral IV is not available because of severe extremity burns, a central venous line may be placed. Children with large burns should have two large-bore IV lines for fluid administration. The presence of two IV lines also provides a safety margin if one infiltrates, to allow continued resuscitation while another line is re-established. Either internal jugular, subclavian or femoral lines can be obtained, but femoral venous access may be easier to obtain in edematous patients.

When vascular access is unobtainable the intraosseous route is a viable option. Fluid volumes in excess of 100 mL/h can be administered directly into the bone marrow.⁷ Intramedullary access can be utilized in the proximal tibia until IV access is accomplished. A 16–18 gauge bone marrow aspiration needle, spinal needle, or commercially available intraosseous needle can be used to cannulate the bone marrow compartment. Although previously advocated only for children younger than 3 years of age, intraosseous fluid administration can be safely performed in all pediatric age groups.⁸ The anterior tibial plateau, medial malleolus, anterior iliac crest, and distal femur are preferred sites for intraosseous infusion. The needle should be introduced into the bone, avoiding the epiphysis, either perpendicular to the bone or at a 60° angle, with the bevel facing the greater length of bone (Fig. 35.4). The needle has been properly inserted when bone marrow can be freely aspirated. The needle should be well secured to prevent inadvertent removal. Fluid should be allowed to infuse by gravity drip. The use of pumps should be discouraged in case the needle is dislodged from the marrow compartment.

Figure 35.4 Intraosseous line placement in the proximal tibia (a) and distal femur (b).

(Redrawn with permission from Fleisher G, Ludwig S, eds. Textbook of pediatric emergency medicine, 2nd ed. Baltimore: Williams & Wilkins; 1988: 268.)

Fluid losses are proportionally greater in children owing to their small body weight to body surface area ratio. Normal blood volume in children is approximately 80 mL/kg body weight and in neonates 85–90 mL/kg, compared to an adult whose normal blood volume is 70 mL/kg. Evaporative water losses in a 20% TBSA burn in a 10 kg child are 475 mL or 59% of the circulating volume, whereas the same size burn in a 70 kg adult causes the loss of 1100 mL or only 22% of blood volume. The commonly used ‘rule of nines’, useful in adults and adequate in adolescents, does not accurately reflect the burned body surface area of children under 15 years of age (Fig. 35.5). The standard relationships between body surface area and weight in adults do not hold true in children, as infants possess a larger cranial surface area and a smaller area in the extremities than adults. Most routinely used resuscitation formulas were developed using adult patients and are almost exclusively weight-based. Since the linear relationship between weight and body surface area does not exist in children, use of these formulas in children results in under- or over-resuscitation (Table 35.1).

Figure 35.5 The ‘rule of nines’ altered for the anthropomorphic differences of infancy and childhood.

Table 35.1 Resuscitation by the Parkland formula only compared to maintenance fluid requirements alone

Pediatric burn patients should therefore be resuscitated using formulas based on body surface area, which can be calculated from height and weight using a standard nomogram (Fig. 35.6) or formulas (Table 35.2). The most commonly used resuscitation formula in pediatric patients calls for the administration of 5000 mL/m² TBSA burned plus 2000 mL/m² TBSA for maintenance fluid given over the first 24 hours after burn, with half the volume administered during the initial 8 hours and the second half given over the following 16 hours.⁹ The subsequent 24 hours, and for the rest of the time their burn wound is open, require 3750 mL/m² TBSA burned or remaining open area plus 1500 mL/m² TBSA for maintenance requirements. The fluid requirement decreases as a patient achieves more wound coverage and healing. As in the adult patient, resuscitation formulas offer a guide for the amount of fluid necessary for replacing lost volume in children, and the amount of fluid should be titrated according to the patient’s response.

Figure 35.6 Standard nomogram for the determination of body surface area based on height and weight. The example depicted is for a child of 100 cm in height and 23 kg in weight.

(Reprinted with permission from Eichelberger MR, ed. Pediatric trauma: prevention, acute care and rehabilitation. St Louis: Mosby Year Book; 1993: 572.)

Table 35.2 Formulas for calculating body surface area (bsa)