Chapter 216: Thermal Burns

EPIDEMIOLOGY

An estimated 450,000 individuals in the United States receive medical treatment each year for burn injuries. Although 40,000 patients require hospitalization and more than 60% of those are treated at one of 127 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. Seventy-seven percent of all injuries are accounted for by fire or scalding; 43% of scald injuries occur in children less than 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 disproportionately higher death rate.^4,5,6 The risk of death from a major burn increases with larger burn size, older age, the presence of inhalation injury, and female sex.⁶

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.⁷

Care of the acute burn–injured patient has improved significantly over the last 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. Only approximately 4% of those treated in specialized burn treatment centers die from their injuries or associated complications.^4,10

PATHOPHYSIOLOGY

Skin consists of two layers: the epidermis and the dermis (Figure 216-1). 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 varies 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 homeostatic disorders that contribute to burn shock (Table 216-1). These include disruption of normal cell membrane function, hormonal alterations, acid-base disturbance, hemodynamic changes, and hematologic derangement.