Introduction

A contemporary understanding of burn injuries is essential for all out-of-hospital providers. Burn injuries carry high morbidity and mortality, resulting in severe pain, scarring, and permanent disability. Additionally, specialized resources such as burn centers are required for care and recovery.

Deaths from fires and burns are the third leading cause of fatal home injury. The US burn mortality rate ranks eighth among the 25 developed countries [1]. According to the American Burn Association National Burn Repository 2012 statistics, over 450,000 victims received medical treatment for burns in the US in the last decade [1]. The majority of these burns result from fire and/or flame injuries and contact with hot objects. Chemical burns account for approximately 3% of burns and 7% of burn admissions annually. Approximately 3,400 deaths occurred (most from smoke inhalation), including 2,550 deaths from residential fires (most from cooking), 300 from vehicle crash fires, and 550 from other sources (approximately 150 deaths from flame burns or smoke inhalation in non-residential fires, 400 from contact with electricity, scalding liquids, or hot objects). Although the number of fatalities and injuries from residential fires has declined gradually, many residential fire-related deaths remain preventable and pose a significant public health problem. Over 60% of US acute burn hospitalizations were admitted to 127 burn centers [1]. Such centers each average over 200 annual admissions for burn injury and skin disorders requiring similar treatment. The other 4,500 US acute care hospitals average fewer than three burn admissions each per year [1–4]. Fire and burn injuries represent 1% of the incidence of injuries and 2% of the total costs of injuries, or $7.5 billion each year [5]. Risk factors for burn injuries include extreme age groups (<4 years and >65 years), poverty, African and Native American descent, and rural area dwellers.

Pathophysiology

Most adults have sustained burns during their lives. The skin is the largest organ in the body and serves as a barrier to outside insults and injuries. The skin protects against water loss, entrance of undesirable substances (microorganisms, toxins), mechanical shock and forces, extreme environmental temperatures, and ultraviolet light damage to keratin and melanin. Furthermore, the skin is involved in sensory perception, temperature regulation, and biochemical activities (e.g. vitamin D synthesis).

The skin is made up of three basic layers. The outer layer, the epidermis, is the thin outer layer of the skin which consists of the stratum corneum containing fully mature keratinocytes which produce fibrous proteins (keratins) that are continuously shed (prevents the entry of most foreign substances as well as the loss of fluid from the body), the keratinocyte layer containing living keratinocytes (squamous cells), and the basal layer, the deepest layer of the epidermis, containing basal cells (continually dividing and forming new keratinocytes). The middle layer of the skin, the dermis, contains blood vessels, lymph vessels, hair follicles, sweat glands, fibroblasts, and nerves. The dermis is held together by collagen, made by fibroblasts, and gives skin flexibility and strength. The dermis also contains pain and touch receptors. The subcutis is the deepest layer of skin and consists of a network of collagen and fat cells that aid in conserving the body’s heat and protect the body from injury by acting as a “shock absorber.”

Severity

Accurate assessment of the burn patient and appropriate institution of early care are critical to optimal outcomes. Although burn size and depth are obvious factors in determining burn severity, the location (body part) of the burn, age of the patient, preexisting disease, and presence of trauma, including inhalation injury, may complicate treatment. Specific anatomical locations of burns often result in significant morbidity and mortality disproportionate to burn size (i.e. head, neck, hands, feet, perineum, and genitalia).

Furthermore, patients <2 years or >50 years old are at higher risk of complications and death than the remaining population [1]. In infants, thin skin, limited reserves, and high surface area-to-mass ratios contribute to this risk, whereas thinning skin and medical problems commonly associated with aging are major factors in older individuals. Young children are also at risk for burns caused by abuse. These injuries are most often scald burns from tap water, are deeper than those seen in the general pediatric burn population, and commonly involve the lower extremities, buttocks, and genitalia. Pediatric and elderly burns may often be an initial presentation of abuse and should be considered in the differential diagnosis.

There are several ways to classify burns (depth, severity, and surface area).