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Clinical Hub,References,Burn Basics

Burn Assessment

Burn Assessment - Clinical Hub, References, Burn Basics



Skin, the largest organ of the body, has many functions including temperature regulation, prevention of fluid loss, transmission of sensation and a barrier to infection. The epidermis is the outermost layer of skin. The epidermis extends into the dermis by way of the skin appendages: hair follicles, sebaceous glands and apocrine and eccrine sweat glands, some of which extend all the way into the fat. It is composed of keratinocytes that can rapidly proliferate and differentiate when wounded if the epithelial stem cell population present in the skin appendages remain intact. Skin varies in thickness from 0.02 mm in the eyelids to several millimeters in calluses on the foot. When the epidermis is destroyed, as in all burns greater than first degree, the epidermis begins to regenerate from intact epidermal stem cells around the margin of the wound and from remaining skin appendages. These cells bridge the wound first, manufacturing a basement membrane as they go, before differentiating upward. The ultimate fate of keratinocytes in the epidermis is to die and form the cornified layer of the epidermis which provides the barrier function of the skin.

Epidermal cells can sometimes be seen as “pearls” or “skin buds” on the wound as they migrate out of the appendages (usually apparent at one to two weeks after a partial thickness burn) and are a sign of healing. Epithelial cells migrate under a variety of stimuli (loss of contact inhibition, etc.) and can migrate up to a millimeter a day; however, the total distance they can spread from an intact site is limited to about one centimeter without disordered healing leading to excessive scarring

The dermis is the stromal tissue that supports the epidermis and provides durability and elasticity to the skin. It is made up primarily of an interwoven collagen and elastin matrix supplemented by GAG’s and populated by fibroblasts, capillaries, nerves, and wandering immune cells. The dermis has no regenerative capacity and heals by scar formation. Dermal thickness varies from less than 0.5 mm in the eyelid to 3-4 mm on the back.

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A scar is formed by disorganized deposition of collagen and ground substance/glycosaminoglycans(GAGs), elastin is not replaced. Vascular ingrowth accompanies this process as well. Clinically, scars become raised, red and pruritic, and have a tendency to contract, usually reaching a peak at 3-4 months after injury and slowly resolving over the next 9-20 months. A scar without redness is considered mature and unlikely to change further with time. While a scar is immature (red and raised) it can be manipulated by frequent stretching to maintain range of motion, and by pressure with compression garments, topical silicone and scar massage to limit hypertrophy. Pressure is thought to work by altering blood flow to hypertrophic tissue and encouraging the collagen to reform more normally.

Pressure flattens the tissue and makes the long-term result more acceptable. Pressure also tends to compensate for the hydrostatic distention of local capillaries in burn wounds that causes discomfort. Patients may have improvements in pain and pruritis with the use of pressure garments.

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First-degree Burns

A first-degree burn extends only into the epidermis but not extending to the basal layer. No blisters are seen. Erythema is visible and the dry epidermis eventually sloughs off leaving a dry, intact epidermal layer behind. Sunburn is a good example. These burns can be painful, but as the barrier function of the skin remains intact, there is no increased risk of infection or fluid imbalance. First-degree burns are treated with soothing lotions such as aloe vera and analgesics. These burns do not need admission to the burn unit but these wounds should be verified with the burn attending because it is sometimes difficult to determine early on if it is 1st or superficial partial thickness (2nd degree burns).

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Second-degree Burns (Partial Thickness Burns)

Also known as partial thickness burns, the damage in second degree burns extends beyond the basal layer of the epidermis into the dermis. These burns are clinically divided into superficial partial thickness and deep partial thickness. Superficial partial thickness burns are limited to the upper, papillary portion of the dermis and will heal within two weeks with minimal to no scarring. Initially these burns appear blistered or moist, pink, painful and blanch when depressed. Deep partial thickness burns extend into the lower, reticular dermis and take longer than three weeks to heal, allowing activation of a significant scarring response. These appear dry, pale or cherry red and do not blanch with pressure. Deep partial thickness burns have better functional and cosmetic results if autografted.

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Third-degree Burns (Full Thickness Burns)

Also known as full thickness burns, the damage in third degree burns extends completely through the dermis and into the subcutaneous areolar tissue. These burns appear white (or charred), dry and are leathery to the touch. All third-degree burns require surgery unless they are very small and can heal acceptably from the margins. Additionally, in the elderly population or poor wound healing patients (thin skin, fragile diabetics, chronic steroid use), we may consider allowing a prolonged course of watchful waiting to assess wound healing capacity if the patient is able to tolerate wound care and even potentially allow for discharge rather than creating another wound (donor site) that may be difficult to heal.

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Indeterminate (Deep Partial Thickness Burns)

Sometimes on presentation it is difficult to differentiate between a second- and third-degree burn (e.g., a dry wound that is pink and blanches). This determination becomes easier over time, but may need to be initially categorized as indeterminate until a later date.

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Fourth-degree Burns

Fourth-degree burns extend into the deep structures under the investing fascia, such as tendons, muscle and bone. Electrical burns, molten metal burns, flame burns where the victim is trapped or unconscious, and sometimes immersion scald burns are examples of fourth degree burns.

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Estimating Total Body Surface Area Burn Injury

The body can be fairly accurately divided into known percentage areas of the total body surface. These are represented on a hospital form known as the burn diagram. Every patient admitted to the burn center with a burn requires a burn diagram in the problem oriented charting and notes. It is a found in the smart-text box in HealthLink under Burn Lund-Browder Burn Chart Adult – see below). An initial burn diagram should be filled out at the time of admission. The total burn size (first, second and third-degree) is calculated for hospital charging and coding purposes. The burn size used for Parkland formula and other calculations is the combination of second and third degree burns.

In order to estimate the patient’s energy needs and fluid losses post-operatively, unhealed donor sites are counted as open wounds. However, we do not document donor sites in the Lund Browder chart. You must fill out a final burn diagram at the time of discharge including areas grafted as 3rd degree, and areas of burn that have healed or are healing as 2nd degree.

Lund - Browder Burn Calculation

Age: Adult



1st deg

2nd deg

3rd deg











Ant trunk





Post trunk





R buttock





L buttock










R upper arm





L upper arm





R lower arm





L lower arm





R hand





L hand





R thigh





L thigh





R leg





L leg





R foot





L foot





Total 2nd & 3rd degree burns 



TBSA % burned (2nd + 3rd) 



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When denatured by heat, skin becomes eschar and loses all elastic properties, The eschar limits expansion of the underlying tissue as edema forms in circumferential extremity burns. This process will eventually lead to ischemia and escharotomies may be necessary to allow expansion. In most instances escharotomies can be performed at the bedside. Escharotomies are not limited to only dry leathery third degree burns. There are times when deep partial thickness circumferential burns also require eshcarotomies. If there is concern at all that compartment syndrome is an issue, escharotomies should be performed. This most often is necessary on the extremities, but can also be necessary on the chest and abdomen if abdominal or chest compartment syndrome occur.  The images below depicts the typical location of the escharotomies. The incisions must go through the entire burned area to avoid a tourniquet effect from a small band remaining circumferentially. The incisions should be carried through the eschar to the fat.



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‌Reviewed by Burn Director, May 2016