Silverstein and Hopper Chapter 130: Thermal Burn Injury

What are the two major parameters used to assess burn wounds?

Depth of the injury

Percentage of body surface area involved

First Degree Burn Depth

Superficial (epidermis only)

Superficial (Epidermis Only) Burn Appearance

Erythematous

Painful to touch

Superficial (Epidermis Only) Burn Healing

Healing is rapid; reepithelializes in 1 week with topical wound management

No systemic effects

Second Degree Burn Depth

Epidermis and superficial part of dermis

or

Epidermis and deeper part of dermis

Epidermis and Superficial Part of Dermis Burn Appearance

Epidermis will be charred and sloughs; plasma leakage occurs

Hair follicles spared

Painful to touch

Epidermis and Superficial Part of Dermis Burn Healing

Healing by epithelialization from the wound margin with minimal scar in 10-21 days

May have systemic effects

Epidermis and Deeper Part of Dermis Burn Appearance

Skin appears black or yellow-white

Hair follicles destroyed

Decreased pain sensation

Epidermis and Deeper Part of Dermis Burn Healing

Healing by contraction and epithelialization but scarring is significant without surgical intervention

Significant systemic effects expected

Third Degree Burn Depth

Full thickness (entire epidermis and dermis)

Full Thickness (Entire Epidermis and Dermis) Burn Appearance

Skin is black, leathery; eschar insensitive to touch

Full Thickness (Entire Epidermis and Dermis) Burn Healing

Healing often requires extensive surgical intervention, possible skin grafts and flaps

May have life-threatening systemic effects

Fourth Degree Burn Depth

Full thickness (with extension to muscle, tendon, and bone)

Full Thickness (with Extension to Muscle, Tendon, and Bone) Burn Appearance

Skin is black, leathery; eschar insensitive to touch

Full Thickness (with Extension to Muscle, Tendon, and Bone) Burn Healing

Skin grafts and flaps usually required to prevent scarring that could restrict joint movements

How many days can it take a burn to “declare” itself?

• It can take up to 3 days or more for the burn to "declare" itself and during that time thermal injury and circulatory compromise from thrombosed vessels can continue

Patients with burning involving what % of their total body surface area can have serious cardiovascular, pulmonary, and metabolic derangements?

More than 20%

Patients with what % of their total body surface area have a poor prognosis and euthanasia should be discussed?

More than 50%

Rule of Nines

Total body surface area can be estimated in animals using percentages allotted to the body area using the rule of nines

Within how many days does skin form an eschar if severely burned?

Within 7-10 days

Eschar

• Deep cutaneous slough of tissue composed of full-thickness degenerated skin

  • Appears as a black, firm, thick movable crust that separates from the surrounding skin

  • Purulent exudates often lie beneath the eschar

Metabolic Derangements from Burns

• If more than 20% of a patient's TBSA is burned or if the wounds are classified as second or third-degree, hypovolemic shock often occurs

• As a result of capillary thrombosis and plasma leakage, massive amounts of fluid are retained in the wound, often leading to burn wound edema

  • Results in loss of fluid and electrolytes, with the most dramatic losses occurring within the first 12 hours

• By 48 hours after injury, plasma volume is mostly restored so patients are at high risk for generalized edema and fluid overload from the high initial demands for fluid replacement

What should a burn patient be assessed for from days 2-6?

Anemia, DIC, immune dysfunction, SIRS, and early burn wound infection

What should a burn patient be assessed for from day 7 on?

Hyperthermia or fever, hypoxemia, pneumonia, sepsis, and wound demarcation

After initial shock resuscitation, what should total fluid delivery rate during the first 24 hours be for a burn patient?

1-4 ml/kg body weight x %TBSA burned

Antimicrobial Therapy for Burns

• Sepsis is one of the greatest threats to burn patients with extensive TBSA involvement because bacteria can colonize and proliferate in wounds that have lost the protective skin barrier

• Prevent local and systemic skin infection by protecting the wound from contamination in the hospital environment and removal all necrotic tissue and purulent exudates from the wound surface as aggressively as possible through serial debridement

• Systemic antimicrobials are not indicated unless the patient is immunocompromised, has pneumonia or pulmonary injury, or sepsis is suspected

• Topical antibiotics are the antimicrobial treatment of choice

  • Most invasive burn wound infections are caused by Pseudomonas or other gram negative organs, antimicrobials against these bacteria are used until culture results are available

What can you do if a patient presents within 2 hours of the burn injury?

• If the patient presents within 2 hours of the burn injury, cold water lavage for 30 minutes will often help to release heat from the skin and limit the depth of the injury or can submerge the affected area in a cold water bath

  • If large areas are affected must prevent iatrogenic hypothermia

Treatment in Patients with Superficial or Superficial Partial-Thickness Burns

Can use daily lavage and topical agents alone until the extent and depth of the wound is determined

Treatment for Deep Partial-Thickness and Full-Thickness Burns

• Require debridement which can be done conservatively or surgically

  • Conservative often used for the first 3-7 days until the wound declares itself and the patient stabilizes

What should you use to lavage a burn wound?

• When lavaging the wound use a 35 ml syringe and a 19 gauge needle to create a pressure of 8 psi

  • Higher pressures may induce tissue trauma and cause deeper seeding of bacteria into the burn

Treatment for Deep Partial-Thickness and Full-Thickness Burn Wounds

• Aggressive surgical excision of an entire burn wound is indicated in deep partial-thickness and full-thickness burn wounds

  • Ideally close primarily, otherwise allow to heal by second intention and a flap or skin graft can be performed

What are the most common topical agents used for burns?

Aloe vera and SSD

Aloe Vera for Burns

• Aloe vera cream has antithromboxane effects that prevent vasoconstriction and thromboembolic seeding of the dermal vasculature

  • Ideally using it within the first 24 hours can help prevent progression of superficial partial-thickness burns

SSD for Burns

• Apply SSD after the first 24 hours

  • Has a wide spectrum of bactericidal activity against G+ and G- bacteria and Candida

Benefits of Medicinal Honey for Wounds

• Benefits include antibacterial, antiinflammatory, antiedematous, and antioxidant effects

Healing Time for Superficial and Partial-Thickness Burn Wounds

• Superficial and partial-thickness burn wounds have a favorable outcome with no surgical intervention

  • Reepithelialize quickly and can heal within 1-3 weeks

Healing Time for Deeper Burns Involving the Hair Follicles

Heal more slowly (3 weeks or longer)

Healing and Closure for Deep Dermal Partial-Thickness and Full-Thickness Burns

• Deep dermal partial-thickness and full-thickness burns heal by contraction and epithelialization once a healthy granulation bed has been created

  • Can eventually be closed primarily

• Full-thickness burns covering large areas of the body or on the limbs may require skin grafts or flaps for complete closure

Complications of Burns

• Scarring and wound contracture are the biggest complications in patients with burn wounds left to heal by second intention