mentioned above, if early evidence of upper airway edema is present, early intubation is required because the upper airway edema normally increases over 9 to 12h. Prophylactic intubation without good indication however should not be performed.

Advances in ventilator technology and treatment of inhalation injury have resulted in some improvement in mortality. A multi-center, randomized trial in patients with acute lung injury and acute respiratory distress syndrome showed that mechanical ventilation with a lower tidal volume than traditionally utilized, resulted in decreased mortality and increased the number of days without ventilator use [39]. Pruitt’s group showed that since the advent of high-frequency ventilation, mortality has decreased to 29% from 41% reported in an earlier study [40]. Management of inhalation injury consists of ventilatory support, aggressive pulmonary toilet, bronchoscopic removal of casts, and nebulization therapy [11]. Nebulization therapy can consist of heparin,-mimetics, or polymyxin B and is applied between 2–6 times a day. Pressure-control ventilation with permissive hypercapnia is a useful strategy in the management of these patients and P CO2 levels of as much as 60 mm Hg can be well tolerated if arrived at gradually. Prophylactic antibiotics are not indicated, but imperative with documented lung infections. Clinical diagnosis of pneumonia includes two of the following [32]: Chest x-ray revealing a new and persistent infiltrate, consolidation, or cavitation; sepsis (as defined in Table 3) and/or a recent change in sputum or purulence in the sputum, as well as quan-

titative culture. Clinical diagnosis can be modified after utilizing microbiologic data three categories according to the “American Burn Association Consensus Conference to Define Sepsis and Infection in Burns” [32]. Empiric choices for the treatment of pneumonia prior to culture results, should include coverage of methicillin-resistant Staphylococcus aureus and gram-negative organisms such as Pseudomonas and Klebsiella [41].

Burn wound excision

Methods for handling burn wounds have changed in recent decades and are similar in adults and children. Early excision and closure of the burn wound has been probably the single greatest advancement in the treating patients with severe thermal injuries during the last twenty years; leading to substantially reduced resting energy requirements, subsequent improvement of mortality rates and substantially lower costs in this particular patient population [11, 42–45]. Early wound closure has been furthermore found to be associated with decreased severity of hypertrophic scarring, joint contractures and stiffness, and promotes quicker rehabilitation [11, 42].

Techniques of burn-wound excision have envolved substantially over the past decade. In general most areas are excised with a hand skin graft knife or powered dermatome. Sharp excision with a knife or electrocautery is reserved for areas of functional cosmetic importance such as hand and face. In partial

thickness wounds an attempt is being made to preserve viable dermis, where as in full thickness injury all necrotic and infected tissue must be removed leaving a viable wound bed of either fascia, fat or muscle [46]. The following techniques are mainly utilized:

Tangential excision. This technique first described Janzekovic in the 1970s requires repeated shaving of deep dermal partial thickness burns using a Braithwaite, Watson or Goulian or dermatome set at depth 5–10/1,000 inch until a viable dermal bed is reached, which is manifested clinically by punctuate bleeding from the dermal wound bed [46].

Full thickness excision. A hand knife such as the Watsonorpowereddermatomeissetatat15–30/1,000 inch and serial passes are made excising the full thickness wound. Excision is aided by traction on the excised eschar as it passes through the knife or dermatome. Adequate excision is signaled by a viable bleeding wound bed, which is usually fat [46].

Fascial excisison. This technique is reserved for burn extending down to through the fat into muscle, where the patient presents late with large infected wounds and inpatients with life-threatening invasive

fungal infections. It involves surgical excision of the full thickness of the integument including the subcutaneous fat down to the fascia using Goulian knives and number 11 blades. Unfortunately, fascial excision is mutilating and leaves a permanent contour defect, which is near impossible to reconstruct. Lymphatic channels are excised in this technique and peripheral lymphyedema may develop [46].

Most patients can be managed with layered excisions that optimize later appearance and function. Published estimates of the amount of bleeding associated with these operations range within 3.5 to 5 % of the blood volume for every 1 % of the body surface excised [47, 48]. The control of blood loss is one of the main determinants for outcome [49]. Therefore several techniques should be applied to control blood loss. Local application of fibrin or thrombin spray, topical application of epinephrine 1:10 000–1:20 000, epinephrine soaked lab-pads (1: 40 000), and immediate electrocautery of the blood vessel can control blood loss [50]. The use of a sterilized tourniquet can also limit blood loss [51]. Lastly, pre-excisional tumescence with epinephrine

saline can be used on trunk, back, extremities, but not fingers.

Burn wound coverage

Various biological and synthetic substrates have been employed to replace the injured skin post-burn. Autografts from uninjured skin remains the mainstay of treatment for many patients. Since early wound closure using autograft may be difficult when full-thickness burns exceed 40% total body surface area (TBSA), allografts (cadaver skin) frequently serve as skin substitute in severely burned patients. While this approach is still commonly used in burn centers throughout the world, it bears considerable risks, including antigenicity, cross-infection as well as limited availability [52]. Xenografts have been used for hundreds of years as temporary replacement for skin loss. Even though these grafts provide a biologically active dermal matrix, the immunologic disparities prevent engraftment and predetermine rejection over time [53]. However, both xenografts and allografts are only a mean of temporary burn wound cover. True closure can only be achieved with living autografts or isografts. But the widespread use of cultured autografts is frequently hampered by poor long term clinical results, exorbitant costs and fragility and difficult handling of these grafts [53–55]. Alternatively, dermal analogs have been made available for clinical use in recent years. Integra was approved by the United States Food and Drug administration for use in life-threatening burns and has been successfully utilized in immediate and delayed closure of full-thickness burns, leading to reduction in length of hospital stay, favorable cosmetics, and improved functional outcome in a prospective and controlled clinical study [56–59]. Our group recently conducted a randomized clinical trial utilizing IntegraTM in the management of severe full-thickness burns of ≥ 50% TBSA in a pediatric patient population comparing it to standard autograft-allograft technique, and found Integra to be associated with attenuated hepatic dysfunction, improved resting energy expenditure and improved aesthetic outcome post-burn [60]. AllodermTM, an acellular human dermal allograft, has been advocated for the management of acute burns. Small clinical series and case

reports suggest that AllodermTM may be useful in the treatment of acute burns [61–64]. Tissue engineering technology is advancing rapidly. Fetal constructs have recently been successfully trialed by Hohlfeld et al. [65] and the bilaminar skin substitute of Boyce [66] is now routine in clinical use and promise spectacular results [50]. Advances in stem cell culture technology are expected to deliver full cosmetic restoration for burn patients [67].

Metabolic response and nutritional support

The response to burn injury, known as hypermetabolism, occurs most dramatically following severe burn its modulation constitute an ongoing challenge for successful burn treatment [68]. Increases in oxygen consumption, metabolic rate, urinary nitrogen excretion, lipolysis and weight loss are directly proportional to the size of the burn [69]. Metabolic rates of burned children can dramatically exceed those of other critical care or trauma patients and cause marked wasting of lean body mass within days after injury [10]. Failure to circumvent the subsequent large energy and protein requirements may result in impaired wound healing, organ dysfunction, susceptibility to infection and death [70]. Thus, adequate nutrition is imperative for the treatment of severely burned patients. Due to the significant increase in energy expenditure post-burn, high-calorie nutritional support was thought to decrease muscle metabolism [71]. However, a randomized, double blinded, prospective study performed by our group found that aggressive high-calorie feeding with a combination of enteral and parenteral nutrition was associated with increased mortality [72]. Most authors therefore recommend adequate calorie intake via early enteral feeding and avoidance of overfeeding to attenuate the catabolic response after injury [10, 11]. Different formulations have been developed to address the specific energy requirements of burned adult and pediatric patients [73–75]. In children, formulas based on body surface area are more appropriate because of the greater body surface area per kilogram. The formulas change with age based on the body surface area alterations that occur with growth (Table 3).