Burns

What are the 5 different causal categories for burns?

1. Flame: damage from superheated, oxidized air

2. Scald: damage from contact with hot liquids

3. Contact: damage from contact with hot or cold solid materials

4. Chemical: contact with noxious chemicals

5. Electrical: conduction of electrical current through tissues

What is a 1st-degree burn?

• Injury localized to the epidermis

What is a superficial 2nd-degree burn?

• Injury to the epidermis and superficial dermis

What is a deep 2nd-degree burn?

• Injury through the epidermis and into the deep dermis

What is a 3rd-degree burn?

• Full-thickness injury through the epidermis and dermis into the subcutaneous fat

What is a 4th-degree burn?

• Injury through the skin and subcutaneous fat into underlying muscle or bone

Identify the depth of the burn:

• A painful, erythematous burn with an intact epidermal barrier that blanches to the touch?

• 1st degree

• Painful burn with blebs and blisters; hair follicles intact; blanches to the touch?

• Superficial 2nd degree

• Sensation decreased; loss of hair follicles?

• Deep 2nd degree

• Leathery feeling, no sensation?

• 3rd degree

What are the 3 zones of injury from a burn?

• Zone of coagulation, zone of stasis, zone of hyperemia

Define the zone of coagulation:

• Irreversibly damaged necrotic area of a burn where cells have been disrupted

Define the zone of stasis:

• Area associated with vascular damage and leakage that is immediately adjacent to the necrotic zone with a moderate degree of insult and decreased tissue perfusion that can either survive or progress to coagulative necrosis

Zone of hyperemia:

• Area of vasodilation from inflammation surrounding the burn with viable tissue where the healing process begins

How can you differentiate a superficial 2nd-degree from a deep 2nd-degree burn?

• Superficial 2nd-degree burn will blanch to the touch, whereas deep 2nd-degree burn will not

Where does a superficial 2nd-degree burn re-epithelialize from?

• Rete ridges; hair follicles; sweat glands (7–14 days)

Where does a deep 2nd-degree burn re-epithelialize from?

• Hair follicles; sweat gland keratinocytes (14–35 days)

Where does a 3rd-degree burn re-epithelialize from?

• Wound edges

According to the rules of nines, what percentage of total body surface area (TBSA) do these regions represent in an adult?

• Each upper extremity?

• 9% TBSA

• Head and neck?

• 9% TBSA

• Each lower extremity?

• 18% TBSA

• Anterior torso?

• 18% TBSA

• Posterior torso?

• 18% TBSA

• Perineum and genitalia?

• 1% TBSA

What percentage of TBSA does the open hand (palm with fingers extended) of the patient account for?

• 1%; this area can be visually transposed onto the burn for an estimation of size.

What percentage do the head and neck account for in the TBSA of an infant?

• 21%

What percentage does each leg account for in the TBSA of an infant?

• 13%

What formula estimates the amount of fluid needed for the resuscitation of a burn patient?

• Parkland Formula: give 4 mL/kg × % burn in first 24 hours

• Give ½ in first 8 hours, the rest in next 16 hours

• Use for burns ≥20%

• Use lactated Ringer solution

What is the best measure of adequate resuscitation?

• Urine output

• Adults: 0.5 to 1.0 mL/kg/h

• Children <6 months: 2 to 4 mL/kg/h

How do you calculate the Galveston formula for maintenance fluid in the first 24 hours for a pediatric burn patient?

• 5000 mL/TBSA burned (in m²) + 1500 mL/m² total area

What is the treatment for a 1st-degree burn?

• Topical soothing salves; oral nonsteroidal anti-inflammatory agents

What is the treatment for a superficial 2nd-degree burn?

• Clean wound with antiseptic soap to remove dead skin and foreign material

• Unroof blisters

• Apply topical antibiotic and dress wound

What is the treatment for a deep 2nd- and 3rd-degree burns?

• Initially treat like superficial 2nd-degree burns

• Follow with early excision and grafting (within 72 hours)

• Lower mortality rate

• Can mobilize early (improved joint function and short hospitalization)

What is an autograft?

• Skin graft from the patient

What is an allograft?

• Skin graft from same species (cadaver); allows for temporary wound coverage until autograft can be done

What is a homograft?

• Same as allograft

What is a xenograft?

• Skin graft from a different species (porcine)

What antimicrobial soak can cause methemoglobinemia?

• 0.5% Silver nitrate

What antimicrobial soak can cause metabolic acidosis?

• 5% Mafenide acetate inhibits carbonic anhydrase.

What topical antibiotic can cause a transient leukopenia?

• 1% Silver sulfadiazine (aka Silvadene)

What topical antibiotic can penetrate eschar?

• 11% Mafenide acetate (aka Sulfamylon)

• Other characteristics: pain when applied to skin, allergic rash, carbonic anhydrase inhibition

What antimicrobial soak can stain surface a gray or black color when dry?

• 0.5% Silver nitrate solution

What causes most of the damage with inhalation injury?

• Inhaled toxins

What is an abnormal carboxyhemoglobin?

• >10% in nonsmokers

• >20% in smokers

What is the treatment for carbon monoxide poisoning?

• 100% oxygen; possibly hyperbaric oxygen

What is the substance in Hurricane spray that causes methemoglobinemia?

• Nitrites

What is the treatment of methemoglobinemia?

• Methylene blue

What are the 3 stages of the clinical course for patients with inhalation injury?

• Acute pulmonary insufficiency

• Hypoxia and development of diffuse lobar infiltrates (72–96 hours after injury)

• Clinical bronchopneumonia with expectoration of large mucous casts formed in the tracheobronchial tree (3–10 days after injury)

What is the dose and schedule for nebulized heparin given for inhalation injury?

• 5000 to 10,000 U with 3 mL normal saline every 4 hours

What is the dose and schedule for nebulized acetyl cysteine given for inhalation injury?

• 3 mL of a 20% solution every 4 hours

What is the formula to calculate the daily nutritional needs of a burn patient?

• Curreri formula: 25 kcal/kg/d + 40 kcal/%TBSA

What is the major tissue through which electrical current flows, thus sustaining the most damage?

• Muscle

As a good rule of thumb, how many liters of tap water should be used to lavage a chemical burn?

• 15 to 20 L

What 3 factors are involved in the mechanism of alkali burns?

• Saponification of fat

• Massive extraction of water from cells

• Alkali dissolves and combines with proteins to form alkaline proteinates

• Contains hydroxide ions, which induce further chemical reactions

What is the strongest inorganic acid?

• Hydrofluoric acid

What is the treatment of hydrofluoric acid burn?

• Copiously irrigate with water

• Apply 2.5% calcium gluconate gel, changing the gel at 15-minute intervals until pain subsides

• If pain persists or symptoms recur, give intradermal injection of 10% calcium gluconate (0.5 mL/cm² affected) or give intraarterial injection of calcium gluconate into the affected extremity

How does calcium gluconate work in treating hydrofluoric acid burn?

• Fluoride ion complexes with bivalent cations (calcium, magnesium) to form insoluble salts; systemic absorption of the fluoride ion results in hypocalcemia from intravascular calcium chelation causing life-threatening arrhythmias.