A burn is a tissue injury resulting from excessive exposure to thermal, chemical, electrical, or radioactive agents.

1. Epidermis serves as a barrier to fluid and heat loss and barrier to infection.

2. Dermis: provides the overall structural integrity of the skin and maintains the epidermis.

A. It is essential to distinguish between second-degree and third-degree injuries of the dermis, as the latter require operative intervention.

1. Superficial (first degree) burns involve epidermis only.

a. Erythema; blanch when touched; do not blister.

2. Partial (second degree) burns.

a. Involve epidermis and part of dermis. Divided into superficial and deep.

b. Superficial—blistering, weeping, pink, and painful skin; will reepithelialize.

c. Deep—paler; do not blanch; some sensation remains; take longer to reepithelialize.

3. Full-thickness epidermis, dermis, and even subcutaneous fat, muscle, bone:

a. Pale, leathery, and insensate skin.

4. Injury can progress over time, and partial-thickness burns can convert to full thickness.

A. Risk factors.

1. Infants and elderly are more frequently affected.

2. Cognitive impairment.

a. Behavioral disorders.

b. Impairment from alcohol or drug effects.

B. Prognosis markedly improved in the last 25 years.

1. Lethal dose 50 (LD50) for young adults is a 90% total body surface area (TBSA) burn, and the LD50 for the elderly is a 40% TBSA burn.

2. Shift toward, “early” (within 5 days), operative excision as it was realized that burned tissue drives burn shock.

3. Diminution of burn wound sepsis and advances in critical care borrowed from all disciplines have contributed to improved outcomes for young patients and in the elderly.

4. Clinical data points predicting mortality (mortality rates of 90% when all three are present and 33% when two factors are present):

a. Age older than 60 years.

b. TBSA burned ≥40%.

c. Inhalational injury.

A. Burn shock.

1. Occurs in ≥20% TBSA burns.

2. Due to elements of distributive and hypovolemic shock:

a. Massive insensible evaporative fluid loss from burn wounds.

b. Intravascular volume depletion from interstitial edema in both burned and unburned tissue.

c. Forces central shunting of blood to improve core perfusion, but deprives the burn wound.

B. Massive edema.

1. Occurs in burn wound and nonburned tissue.

a. Results from increased vascular permeability driven by vasoactive mediators, including kinins, serotonin, histamine, prostaglandins, and oxygen radicals.

b. Decreased oncotic pressure.

C. Cardiovascular response.

1. Decreased preload.

2. First 48 hours, decreased cardiac output (myocardial depressant factors likely gut derived).

a. Decreased compliance and contractility, particularly after inhalational injury.

3. After first 48 hours develop hyperdynamic cardiac state that may last for weeks.

D. Infection—increased susceptibility.

1. Lungs.

a. Pneumonia.

b. Tracheobronchitis.

2. Burn wounds:

a. Staphylococcus aureus and Streptococcus first week, followed by Pseudomonas, Klebsiella, and Acinetobacter; Late: Fungus.

3. Central line sites.

4. Urinary tract.

5. Gut.

a. If not fed, may be source of translocation of bacteria and source of sepsis.

b. Enteral feedings can prevent gut atrophy and immunoenhancing nutritional regimens; especially those with glutamine further resist atrophy and may afford better outcomes.

A. History.

1. The heat source and circumstances of the injury.

2. When the burn injury occurs coincidentally with blunt trauma.

a. Life-threatening injuries take precedence in early management.

b. Burn skin management is secondary.

3. If burn occurs in closed space—expect inhalation injury.

B. Electrical injuries.

1. High voltage.

a. May present with little injury to the skin, but significant injuries to the muscle, vasculature, and bone.

b. Cardiac standstill/arrhythmias in first 24 hours.

2. Low voltage.

a. Present as thermal burns, with injuries to the tissue from the outside to inside.

b. Ventricular fibrillation.

A. Multiples of the number 9 (“the rule of nines”) to assess surface area of partial- and full-thickness burns.

B. Lund-Browder scale (Fig. 114-1).

C. For noncontiguous injuries, the palmar surface of the patient’s hand can be used to estimate 1% TBSA.

A. Airway management.

1. Consider early intubation for

a. Inhalational injury (stridor, hoarseness).

b. TBSA > 40% as massive soft tissue edema can occur during resuscitation.

B. Burn shock.

1. Ideal resuscitation perfuses the partial-thickness injury and optimizes organ function.

2. Underperfusion deprives the wound of nutrient delivery and gas exchange, leading to full-thickness conversion.

3. Excessive resuscitation leads to tissue edema, pulmonary edema, abdominal compartment syndrome, and extremity compartment syndrome.

4. Central venous access is generally necessary and preferably placed through uninvolved tissue.

5. Resuscitative regimens.

a. TBSA burned and weight-guide fluid management.

b. No evidence-based level-one data for resuscitative fluids use.