Part 4: Burns, Rule of Nines, Frostbite, Pressure Injuries (Stages 1–4), Unstageable Injuries, Wound Healing, Debridement, Dressings, and Wound Therapies

What is a burn?

A traumatic injury to skin and underlying tissues caused by thermal, chemical, electrical, or radiation exposure.

How are burns classified?

By depth of tissue destruction and total body surface area (TBSA) affected.

What are the two major burn classifications discussed in this lecture?

Partial-thickness burns and full-thickness burns.

What is a superficial partial-thickness burn?

A burn involving superficial epidermal damage with hyperemia while tactile and pain sensation remain intact.

What are the clinical manifestations of a superficial partial-thickness burn?

Erythema, blanching with pressure, pain, mild swelling, and possible blistering after 24 hours.

What are common causes of superficial partial-thickness burns?

Sunburn and quick heat flashes.

Why are superficial partial-thickness burns painful?

Nerve endings remain intact.

What is a deeper partial-thickness burn?

A burn involving the epidermis and dermis to varying depths while retaining viable regenerative skin elements.

What are the manifestations of deeper partial-thickness burns?

Red, shiny, wet skin with ruptured or intact vesicles, severe pain, and mild-to-moderate edema.

Why are deeper partial-thickness burns extremely sensitive to touch?

Nerve injury and exposed dermal structures increase sensitivity.

What are common causes of partial-thickness burns?

Flame, flash burns, scalds, contact burns, chemicals, tar, and electrical current.

What structures remain viable in partial-thickness burns?

Skin elements responsible for epithelial regeneration.

What is a full-thickness burn?

A burn that destroys all skin elements and local nerve endings.

What are the clinical manifestations of full-thickness burns?

Dry, waxy-white, leathery, or hard skin with visible thrombosed vessels and loss of pain sensation.

Why are full-thickness burns often painless?

Nerve endings are destroyed.

What is coagulation necrosis?

Tissue death caused by protein denaturation following severe injury.

Why is surgical intervention often required in full-thickness burns?

The skin cannot regenerate adequately because all regenerative elements are destroyed.

What structures may be affected in severe full-thickness burns?

Muscles, tendons, ligaments, cartilage, and bone.

What are common causes of full-thickness burns?

Flame, scalds, chemicals, tar, and electrical injuries.

What is the Rule of Nines?

A method used to estimate the percentage of total body surface area (TBSA) affected by burns.

How much TBSA does one entire arm represent in the Rule of Nines?

9%.

How much TBSA does the anterior chest represent?

9%.

How much TBSA does the abdomen represent?

9%.

How much TBSA does the upper back represent?

9%.

How much TBSA does the lower back represent?

9%.

Why is estimating TBSA important?

It helps determine burn severity, fluid resuscitation requirements, and treatment priorities.

When is a burn considered severe in children under 10 years?

Greater than 10% TBSA.

When is a burn considered severe in adults?

Greater than 20% TBSA.

When is a burn considered severe in adults over age 50?

Greater than 10% TBSA.

What percentage of full-thickness burns constitutes a severe burn injury?

Greater than 5% TBSA.

What are the major systemic effects of burns?

Fluid shifts, hypovolemic shock, electrolyte imbalances, infection risk, respiratory injury, and organ dysfunction.

What fluid shift occurs after major burns?

Fluid moves from the intravascular space into the interstitial space.

Why do burn patients develop edema?

Capillary permeability increases, allowing fluid to leak into tissues.

What is hypovolemic shock?

A life-threatening condition resulting from severe fluid loss and reduced circulating blood volume.

Why are burn patients at risk for hypovolemic shock?

Massive capillary leak causes significant intravascular fluid loss.

What electrolyte imbalance commonly occurs early after burns?

Hyperkalemia.

Why does hyperkalemia occur after burns?

Damaged cells release intracellular potassium into the bloodstream.

What is myoglobinuria?

The presence of myoglobin in urine following muscle injury.

Why is myoglobinuria dangerous?

It can cause acute tubular necrosis and acute kidney injury.

What is acute tubular necrosis (ATN)?

Kidney injury caused by ischemia or nephrotoxic substances such as myoglobin.

What is acute kidney injury (AKI)?

A sudden decline in kidney function.

What are contractures?

Permanent shortening and tightening of muscles, tendons, or skin after healing.

Why do burn contractures develop?

Scar tissue formation restricts normal movement.

What is the stress response associated with burns?

A hypermetabolic state characterized by increased energy expenditure and catabolism.

Why are burn patients highly susceptible to infection?

Loss of skin integrity removes a major protective barrier.

What is sepsis?

A life-threatening systemic response to infection causing organ dysfunction.

Why are severe burn patients at risk for sepsis?

Open wounds provide portals of entry for microorganisms.

How can burns affect the respiratory system?

Through smoke inhalation and airway injury.

What is smoke inhalation injury?

Damage to respiratory tissues caused by inhaling heat, smoke, and toxic combustion products.

Describe the pathophysiologic sequence of severe burn injury.

Burn injury → capillary leak → edema → hypovolemia → tissue ischemia → anaerobic metabolism → acidosis → decreased cardiac output → multiorgan dysfunction.