Acute Burn Management and Rehabilitation

Fig. 15.1

These images depict the zones of injury in a burn wound: stasis, hyperemia and coagulation

Each zone exhibits specific characteristics. The zone of coagulation tends to be the central area, comprised of necrotic and nonviable tissue. The zone of stasis surrounds the zone of coagulation and is most vulnerable to ischemia. In this zone, initially blood flow is present. However, if the patient is not appropriately resuscitated, this zone can become ischemic and nonviable. Last is the zone of hyperemia, which surrounds the zone of stasis. This zone is viable. Intense resuscitation efforts are targeted to salvage the zone of stasis and convert it to viable tissue.

Factors predicting the prognosis of burn wounds include extent of the burn, its age, and depth. Depth is characterized as first degree or epidermal, second degree – divided into superficial partial thickness and deep partial thickness – and full thickness also known as third degree. Determining the correct depth is most consistently based on clinical experience, though adjuncts such as dyes, fluorescein, and Doppler flow-meter assist [4].

Burn depth is important not only in predicting mortality but also in terms of rehabilitating and function. The deeper the burn, the more dermis involved and the greater the functional and/or aesthetic deficit. First-degree burns are epidermal, healing with at hyperpigment change only, and are not included in determining the percent TBSA of a burn [4]. Superficial partial thickness burns tend to be limited to the papillary dermis and typically are minor. They will often re-epithelialize with appropriate therapy within 3 weeks. Deep partial thickness burns tend to include the reticular dermis and often do not spontaneously re-epithelialize within 3 weeks. These burns tend to form contractures and severe scars. Surgery is the mainstay of treatment for these deeper burns. Third-degree burns tend to be full thickness and extend into the fat, fascia, muscle, and/or bone. Early surgical management after appropriate resuscitation is the optimal treatment for this depth. The “rule of nines” is utilized in determining TBSA in second- and third-degree burn adult patients (Fig. 15.2).

Fig. 15.2

Rule of Nines:A representation of percent body surface burns by area

According to the American Burn Association [1], patients who fit the following criteria should be referred to a burn center:

1.

Second- and third-degree burns >10 % TBSA in patients under 10 or over 30 years of age
2.

Second- and third-degree burns >10 % TBSA in patients all other age groups
3.

Third-degree burn >5 % TBSA in any age group
4.

Second- and third-degree burns involving the face, hands, feet, genitalia, perineum, or major joints
5.

Electrical burns including lightening
6.

Chemical burns with serious threat to function or cosmetic impairment
7.

Inhalation injuries
8.

Lesser burns in patients with preexisting medical problems which may potentially complicate management
9.

Combined mechanical and thermal injury in which the burn wound poses a great risk

Care of the Acute Burn

As with all resuscitative efforts, burn resuscitation begins with the “ABC” of airway, breathing, and circulation. If suspicion for inhalation injury or inability of patient to secure the airway is high, prophylactic intubation is recommended. Fluid resuscitation is central to preventing burn shock and replacing sequestered fluid. The volume of fluid is most commonly determined by the Parkland formula: 4 ml/kg/% TBSA burn for the first 24 h. Lactated ringer is the fluid of choice and colloid is avoided the first 24 h secondary to protein leak. The best parameter of adequate resuscitation is urine output. Children have different body proportions than adults. For them, the Berkow formula is utilized to calculate TBSA. The Parkland formula should be modified to include maintenance fluid. Urine output of 1 ml/kg/h is the most reliable marker of adequate resuscitation [5].

Inhalational Injury

Inhalation injury affects about 10–20 % of all hospitalized burn patients and may potentially damage the respiratory tract at multiple levels from the oropharynx to the alveolus [6]. An intense inflammatory reaction resulting in significant respiratory edema and damage can lead to bronchopneumonia and pulmonary sepsis. Management includes having a low suspicion for inhalational injury, aggressive and proactive airway management, and bronchoscopy. Singed nasal hair and carbonaceous sputum are pathognomonic for inhalational injury. Laboratory values may reflect increased carboxyhemoglobin levels (>15 %) [6].

Infection

Infection is the most common cause of death in burn patients. Risk of infection increases with increasing TBSA, age (young than 16 and older than 60), environment (hot/moist), ischemia to wound, and medical comorbidities like diabetes, malnutrition, and cardiopulmonary insufficiency. Prior to the era of topical antimicrobials, partial- and full-thickness wounds often became infected and contributed to burn wound sepsis. Routine administration of prophylactic antibiotics is not indicated in burn wounds as it selects for more resistant organisms. Skin biopsy showing greater than 10⁵ organisms per gram of tissue is the standard for determining if a wound is infected. Lower counts may be simple colonization not requiring treatment. The advent of silver nitrate, mafenide, and silver sulfadiazine were instrumental in controlling burn wound sepsis [6].

Burn Surgery

Escharotomy and Fasciotomy

Escharotomy and fasciotomy are performed in the acute burn setting often in patients with larger TBSA burns which are either prohibitive causing respiratory distress or compartment syndrome of an extremity. Any circumferentially burned body area is at risk of ischemia, given the fluid shifts and limitation of lung compliance. One should have a low threshold for fasciotomy if the mechanism is suggestive, i.e., electrical injury, and/or signs of numbness and tingling are present. In the upper extremity, pain on passive range of motion of the digits or increasing peak airway pressures in a circumferential chest burn may suggest impending ischemia or hypoxia and necessitate an emergent decompressive intervention [7]. In the upper extremity specifically, if evidence of an intrinsic minus hand is evident, decompression is indicated. This involves making two radial incisions in the dorsum of the hand. In the lower extremity, medial and lateral incisions are necessary. In a chest escharotomy, an “H” incision is made at the mid-axillary line [7].

Excision and Grafting

The principles of burn surgery are early excision to prevent functionally limiting contracture, prevention of infection, preservation of viable tissue, and maintenance of function. The goal of early excision is to prevent contracture that may lead to tension, resulting in hypertrophic scar formation and, depending on location, limitation of function. Earlier studies demonstrate that early excision may decrease overall mortality but does not change morbidity pattern or cause of death [8].

There is benefit to temporarily covering the wound to avoid infection and for pain relief [8]. If there is not sufficient autograft, cadaver allograft may be utilized. There are numerous physiologic dressings, including cadaver allograft and xenograft. Other dressings include amion and biobrane. Advantages of allograft include its ability to vascularize and its effectiveness in closing the wound. Allograft is, however, cost prohibitive. Examples of xenograft include porcine derivatives. Xenograft is often available in large sizes and can be rapidly applied. Its biggest limitation is lack of incorporation into the wound. Products such as amion and biobrane are not currently widely utilized. Amion is inexpensive and widely available but due to fluid fluxes must be changed every 2–4 days. Biobrane is a synthetic comprised of nylon and silicon that is variably adherent. Autografts such as cultured epidermal cells are autografts which are harvested from the patient and expanded in vitro and are often very expensive and unstable [8].

Principles of Burn Surgery

Although significant variability exists in burn injuries, post-burn deformities have similar components, allowing for a systematic rehabilitative approach. The founding principles of burn surgery are [9]:

1.

Analyze the deformity, making note of distorted and deficient tissue; identify potential donor skin sites early and protect for future use.
2.

Long-term goals, including both functional and aesthetic.
3.

If possible, postpone reconstruction until scars and grafts have matured (usually the 1 year point). Incorporate splints and elastic garments and compression to limit hypertrophic scarring.
4.

Match donor skin to color, thickness, and texture to minimize contracture.
5.

Follow relaxed skin tension lines to orient scars and regional aesthetic units to avoid scars between territories.

Burn Reconstructive Ladder

Burn reconstructive options vary from a simple excision and closure to complex flaps. Although the concept of the reconstructive ladder is fundamental to plastic surgery, it is ultimately the surgeon’s discretion to customize and choose the most appropriate modality.

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