Chapter Four

Evaluation and Classification

of Burn Severity

Chapter Four

Evaluation and Classification of Burn Severity 

Section I. Clinical Assessment of Burn Area

In 1961, Wellace advanced the generally accepted “rule of nines” which, while simple and practical, is not very accurate. The “hand method”, which uses the patient’s hand as a standard for measurement (i.e. the surface area covered by the patient’s hand with fingers closed being roughly 1 % of the whole body surface) is very useful for measurement of small or multiple scattered areas.

The head and neck is 9 % of the area of the whole body, two upper limbs is 18% (2´9), two lower limbs (including buttock) is 46% (5´9+1), the front and the back of the trunk (including perineum) is 27 % (3´9). This proportion may be different according to the patient’s age and gender. Therefore, some more accurate methods have been put forward. In 1970, “Chinese rule of nines” was named, this is based on the actual proportion of body surface area of Chinese people, and is now popularly applied (Table 1). In China, there is another rule named the “rule of tens” which considers the head and the neck area as 10 %, upper limbs 2´10 %, trunk (including perineum and buttock) 3´10 % and lower limbs 4´10 %. This method is also very simple and easy to apply.

Table 4-1. The “Chinese rule of nines” for determination of burn area

  * For adult females, buttocks and feet account for 6 %

Section II. Clinical Evaluation on Depth of the Burns Wound

Since burns wounds are conventionally treated with dry-exposed therapy or bandaging method, the resultant obscuring of the wound by scar or dressing prevents inspection of the wound the next day. People can only see the crust and the dressings, thus it becomes very difficult to estimate wound depth accurately. Though some instruments have been invented for diagnosis of burn depth, their accuracy typically proves to be less than visual estimates by experienced doctors. One advantage of burns regenerative medicine and therapy (MEBT/MEBO) is that burns wounds can be inspected in the whole treatment process by the naked eye. This allows doctors to accurately observe the changes in the wound over time, thus allowing for simple determination of wound depth. At this point, thanks to accurate observation of the pathological changes in the burn area, the clinical characteristics of burns wounds and the clinical diagnosis of burn depth can be summarized as follows. 

1. First-degree burn

Diagnosis of first-degree burns is the same as the conventional surgical standard. The burns wound is erythematous in appearance, has no blister, may be painful and have slight swellings. These wounds typically heal spontaneously by 3 days postburn with varying degrees of epithelial exfoliation. The injured area should not be included when estimating the total extent of the burn since, pathologically speaking, skin was only thermally irritated and not burned, as there was no structure injury to epidermal basal layer and no formation of zone of stasis. MEBO can accelerate the recovery of first-degree burn with resolution of erythematous skin within 24 h and immediate cessation of pain. The injured epithelia in the superficial layer of epidermis can be exfoliated and removed together with the MEBO and no systemic reaction occurs.

2. Second-degree burn

Worldwide, the incidence of second-degree burns is clinically the highest. The pathological changes of second-degree burn are very complicated and, until now, quite difficult to manage. Second-degree burn is often painful and sensitive to pin-pick. The microcirculation in the injured tissue is damaged. Congestion and exudation occur, and the zone of stasis may exist in dermis. When progressive necrosis of the dermal tissue occurs due to microthrombosis formation, this worsen the clinical picture. Second-degree burns destroy the skin barrier and result in a serial systemic reaction and infection. Without application of BRT, as epithelial tissue is seriously injured, the wounds healed with disfiguring and painful scar formation dooming the patient to a lifetime of suffering.

The diagnosis of second-degree burns is not difficult. However, with conventional burns treatments, it is difficult to differentiate between superficial and deep second-degree burns because the wounds can not be inspected directly and clearly. Therefore, the diagnosis is based only on doctor’s conception of the process and not on direct experience. However, when burn regenerative medicime and therapy (MEBT) is applied, there is direct and adequate evidence for establishing the correct diagnosis. 

(1). Superficial II-degree burn

· Scald wound: Within 2 h post-scald, obvious color change occurs in the dermis and blisters of different size appear. After blister exfoliation, the skin tissue looks moist, slightly red with exudation and has good elasticity. Fine hair stands straight and is sensitive to pain when pulled out. The wound is smooth. Two hours later, wound exudate increases with bright red color, and wound swelling (especially wounds in the face). 48 h later, swelling subsides and exudate decreases gradually. Four days later, epidermis of the wound thickens and the wound heals in about 6 days. 

· Burns wound: The wounds may appear different appearances according to different causes, e.g. epidermal layer of the wound burned by a gas fire flame has a dark color. Compared with scald wound, wound surface caused by flame is drier and after removal of the blisters, the wound looks dark red, because flame results in serious dehydration. Pathological changes in burns wounds caused by flame are the same as in scald wounds.

(2). Deep second-degree burns

Deep second-degree burns may be further differentiated into two subtypes: 1) superficial subtype of deep second-degree burn with thermal injuries reaching the dermal papilla layer; 2) deep subtype of deep second-degree burn with injuries reaching dermal reticular layer. The key points to distinguishing the deep second-degree burn from superficial second-degree burn at the early stage are that in the former, the necrotic layer and the zone of stasis do exist in the dermis of the wound, while in the latter, (superficial second-degree burn), there is no formation of either the necrotic layer or the zone of stasis. Therefore, in the treating procedure, superficial second-degree burns wounds do not have liquefied products of necrotic tissue, while deep second-degree burns wounds produce copious amounts of liquefied products from necrotic tissue before the wound healing. 

· The superficial subtype of deep second-degree burns wounds. The appearance of this type of wound is similar to superficial second-degree burns wounds. Scald wounds have blisters of different size and after blister exfoliation, the dermal tissue looks light red or pale with much exudate. The wound has good elasticity. 24 h later, numerous red pin-spots appear in the pale wound while the superficial layer of the dermis becomes semi-transparent, sensitive to pain, and gives a positive reaction when the hair is pulled out. After the exudation stage, the wound looks red, superficial layer of the dermis begins to liquefy, the base of the wound is in a position lower than skin surface. In about 10 days, liquefaction products decrease, the wound grows up to the skin surface. Healing occurs within about 15 days without scar formation. Hyperpigmentation may appear tempora