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Burns

Last updated: March 16, 2021

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Burns are injuries to tissue caused by heat, chemicals, and/or radiation. The two factors that influence the severity of a burn are its depth and the surface area involved. Accordingly, burns are classified into four grades based on the depth of tissue involvement. Lund-Browder charts are used to calculate the surface area involved. Massive tissue necrosis, which occurs with severe burns, results in sepsis, shock, and sequential organ failure (see SOFA score for details). In the case of severe burns, patients should be intubated, given supplemental oxygen, and resuscitated with IV fluids. Different formulas exist to calculate initial fluid requirement, but fluids should be adjusted to maintain clinical stability and appropriate urine output. Pulse oximetry, blood gas analysis, and measurement of electrolyte and creatinine levels are important diagnostic procedures for patients with severe burns. In the case of circumferential burns around limbs, peripheral pulses and capillary refill can be used to detect perfusion. Escharotomy should be performed in order to treat compartment syndrome and prevent acute limb ischemia. First and second-degree burns can be treated with antiseptic ointment and dressings. Treatment of third and fourth-degree burns involves debridement of necrotic tissue followed by skin graft or a tissue transfer via flap. Burn wounds tend to become infected and large, severe burns tend to be fatal injuries. The most common causes of death following burns are shock, sepsis, and respiratory failure.

  • Thermal injury (e.g., scalding, contact with a hot surface, fires)
  • Non-thermal injury: radiation, chemical burns, electrical burns

Although most cases of burns are the result of accidental injury, non-accidental injury must always be suspected in vulnerable populations, including children and the elderly!

Local effects

  • Local changes at the burn site (Jackson model of the burn wound) [1]
    • Zone of coagulation: a central zone of irreversible, coagulative necrosis
    • Zone of stasis: surrounds the central zone of coagulation and is comprised of damaged but viable tissue with decreased perfusion
    • Zone of hyperemia: surrounds the zone of stasis and is characterized by inflammation and increased blood flow

A burn wound is a dynamic wound. If resuscitation and/or wound care are not adequate, the zone of stasis becomes irreversibly damaged and the depth of the burn increases!

Systemic effects [2]

Large (> 30% of the body surface area) and/or deep burns causing extensive tissue damage can lead to systemic effects.

Depth of a burn

Classification of burns

Degree of burns

Depth of tissue damage

Symptoms [3]

Healing process

1st-degree burn (superficial burn)

  • Localized features
  • The burn wound blanches on applying pressure and refills rapidly
  • Features resemble those of sunburn
  • Healing within 3–6 days without scarring

2nd-degree burn

2a (superficial partial-thickness burn)
  • Pain: especially with the movement of air or changes in temperature in the area surrounding the wound
  • Erythema
  • Swelling
  • Local rise of temperature
  • Vesicles/bullae
  • The burn wound blanches on applying pressure and refills slowly.
2b (deep partial-thickness burn)
  • Minimal pain: pain may be felt on applying pressure.
  • Mottled skin with red and/or white patches
  • Vesicles/bullae: fragile (rupture easily)
  • The burn wound only sluggishly blanches on applying pressure.
  • Healing takes 3 weeks or longer and results in scar formation

3rd-degree burn (full thickness burn)

  • No pain (perception of deep pressure is intact)
  • Tissue necrosis with black, waxy-white, or gray leather-like skin (eschar)
  • Dried out, inelastic appearance
  • No vesicles/bullae
  • The burn wound does not blanch on applying pressure.
  • The burn does not heal by itself.

4th-degree burn (deeper injury burn)

  • No pain (minimal perception of deep pressure)
  • Dried out, inelastic appearance
  • Tissue necrosis with black, white, or gray leather-like skin (eschar)
  • The burn wound does not blanch on applying pressure.

In cases of severe, deep burns, pain may be absent as a result of damage to sensory nerve endings!

Extent of burns (surface area involved) [3]

  • Lund-Browder chart
    • Age-specific charts are used to calculate the surface area covered by a burn.
    • Most accurate method for both adults and children
  • Wallace's rule of nines
    • A quick but reliable method for estimating the surface area covered by burns in the case of adults.
    • The rule of nines is unreliable among children.
Body surface area estimation
Segment Adult Small child Infant
Head 9% 16% 18%
Trunk 36% (4 x 9%)
Arms 18% (2 x 9%)
Thighs 18% (2 x 9%) 14.5% 13.5%
Lower legs and feet 18% (2 x 9%) 14.5% 13.5%
Genital region 1%
  • Palm rule
    • The palm accounts for 1% of the total body area.
    • It is the least reliable method.

In the case of adults, shock sets in when burns involve > 15% of the body surface. Burns that involve 50–70% of the body surface are usually lethal. In children, signs of shock appear with > 10% involvement of the body surface and 60–80% body surface involvement is lethal!

Burn severity is based upon clinical history and physical examination, but further testing is conducted to monitor for complications and guide therapy.

Immediate measures in case of severe burns

  • Airway management: intubation and high flow oxygen therapy is indicated if an inhalation injury is suspected or if burns involve more than 30–40% of the body surface. Do not delay intubation if needed, as fluid resuscitation can increase laryngeal swelling, which will complicate intubation
  • Begin initial fluid resuscitation with crystalloids, usually lactated Ringer's solution (RL)
    • In adults and children ≥ age 14
      • Parkland formula was traditionally used to guide initial fluid therapy: the volume of lactated Ringer's solution to be administered within a period of 24 h = 4 mL x % of total body surface involved in 2nd and 3rd-degree burns x body weight (in kg)
      • Current recommendations by the ATLS and the American Burn Association: volume of lactated Ringer's solution to be administered within a period of 24 h = 2 mL x % of body surface involved in 2nd and 3rd-degree burns x body weight (in kg)
      • Half of this volume should be administered within the first 8 hours and the remaining half within the next 16 hours
    • In children < age 14
    • Note that this is an INITIAL estimate for fluid requirements: fluid therapy should be modified to achieve a urine output of 0.5 mL/kg/h in adults and 1 mL/kg/h in children (< 30 kg).
  • Manage the burn area
    • Remove any burnt clothing
    • Cool the burnt area with cool running water or saline-soaked gauzes. Cover the wound with a sterile dressing.
      • Core body temperature should be monitored for hypothermia; if body temperature < 35°C, warm IV fluids can be given
      • Cool with caution or not at all in patients with burns involving >10% BSA as they are particularly vulnerable to hypothermia.

Because of studies demonstrating serious complications from over-resuscitation (e.g., pleural effusions and compartment syndrome), the ATLS and American Burn Association now recommend only giving half of the fluid resuscitation volume that is calculated by the Parkland formula in adults; i.e., 2 mL x %TBSA x weight (kg) instead of 4 mL). The volume is still given over 24 hours, with one half given in the first 8 hours and the remaining half over the next 16 hours.

Patients with burns who cannot take fluids orally also require maintenance fluids. Parkland formula does not include the daily maintenance fluid requirement!

Because fluid resuscitation can worsen laryngeal edema, intubation should be performed before fluid resuscitation!

Do NOT use ice or ice water!

Additional measures

Management based on degree

Burn eschars: specific measures

Small superficial and superficial partial-thickness burns may be treated on an outpatient basis with paraffin gauze, antiseptic ointment, and analgesics.

Chemical burns: specific measures

  • Immediate, copious irrigation of all areas of exposure with water, prior to or on the way to the hospital.
    • Once in the hospital, irrigation should be continued until the pH normalizes

References:[6][7][8]

Postburn hypermetabolism [9][10]

We list the most important complications. The selection is not exhaustive.

  1. Hettiaratchy S, Papini R. Initial management of a major burn: II—assessment and resuscitation. BMJ. 2004; 329 (7457): p.101-103. doi: 10.1136/bmj.329.7457.101 . | Open in Read by QxMD
  2. Hettiaratchy S, Dziewulski P. Pathophysiology and types of burns. BMJ. 2004; 328 (7453): p.1427-1429. doi: 10.1136/bmj.328.7453.1427 . | Open in Read by QxMD
  3. Kumar V, Abbas AK, Aster JC. Robbins & Cotran Pathologic Basis of Disease. Elsevier Saunders ; 2014
  4. Ramos CG. Management of fluid and electrolyte disturbances in the burn patient. Annals of Burns and Fire Disasters. 2000; 13 (4).
  5. Schraga ED. Emergent Management of Thermal Burns . In: Alcock J, Emergent Management of Thermal Burns . New York, NY: WebMD. http://emedicine.medscape.com/article/769193-overview#showall. Updated: May 19, 2016. Accessed: December 12, 2016.
  6. American College of Surgeons and the Committee on Trauma. ATLS Advanced Trauma Life Support. American College of Surgeons ; 2018
  7. Brunicardi F, Andersen D, Billiar T, et al.. Schwartz's Principles of Surgery. McGraw-Hill Education ; 2014
  8. Rice PL, Orgill DP. Emergency care of moderate and severe thermal burns in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/emergency-care-of-moderate-and-severe-thermal-burns-in-adults?source=machineLearning&search=diagnostic%20tests%20for%20burns&selectedTitle=4~150§ionRank=2&anchor=H3#H3.Last updated: April 3, 2015. Accessed: December 12, 2012.
  9. Tenenhaus M, Rennekampff H-O. UpToDate. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/local-treatment-of-burns-topical-antimicrobial-agents-and-dressings?source=see_link§ionName=Burn%20blisters&anchor=H611021630#H611021630.Last updated: July 11, 2016. Accessed: December 12, 2016.
  10. Jeschke MG. Postburn Hypermetabolism: : past, present and future. Journal of Burn Care & Research. 2016; 37 (2): p.86-96. doi: 10.1097/bcr.0000000000000265 . | Open in Read by QxMD
  11. Williams FN, Herndon DN, Jeschke MG. The Hypermetabolic Response to Burn Injury and Interventions to Modify this Response. Clin Plast Surg. 2009; 36 (4): p.583-596. doi: 10.1016/j.cps.2009.05.001 . | Open in Read by QxMD
  12. Pal N. Emergency Escharotomy. In: Schraga ED, Emergency Escharotomy. New York, NY: WebMD. http://emedicine.medscape.com/article/80583-overview#a2. Updated: May 4, 2015. Accessed: December 12, 2016.