Burn management can be broken down to the 5R principles to guide the most suitable therapy for each individual patient. These are as follows: 1. Resuscitation refers to the initial process to stabilize a patient following injury and includes keeping them warm, well perfused, and comfortable. The usual Advanced Trauma Life Support (ATLS) approaches apply with some specific adaptations pertinent to burn injury. Fluid resuscitation is required for most larger burn injury patients as such injuries are associated with fluid loss. Those with total body surface area (TBSA) burns over 10% should be formally resuscitated with one of the preferred formulae such as the modified Brooke or Parkland. In children with larger burns, additional maintenance fluids may also be warranted. In patients with smaller burns, oral fluid resuscitation alone can be sufficient. 2. Resurfacing involves firstly removing burn tissue with either tangential or suprafascial excision, followed by coverage with either temporary dressings, biologic matrices, xenograft, allograft, autograft, or vascularized tissues. 3. Reconstruction refers to the restoration of form and function following burn injury and can be divided in to acute, intermediate, and late reconstruction. 4. Rehabilitation involves early mobilization, splinting, scar management, sensory re-education, strengthening, and conditioning. 5. Recovery involves the return of self-esteem and self-worth, coupled with the confidence to move toward independence, enabling patients to return to school, work, and social functions.1,2
2. Hultman CS, Neumeister MW. Burn care: rehabilitation, reconstruction, and recovery. Clin Plast Surg 2017;44(4):A1–A6, 695–948 The Baux score is a predictor of mortality after a burn injury. It takes into account the patient’s age, the % total body surface area (TBSA) burn, and the presence or absence of inhalation injury. A Baux score is calculated by adding age and % TBSA burn. A score greater than 100 in the presence of an inhalation injury or 110 without an inhalation injury is associated with a 50% mortality. The other factors are also relevant to the prognosis—in particular the patient’s preinjury status, the burn subtype, and burn depth, but do not form part of the Baux scoring system (Fig. 21.1).1–3
3. Advanced Burn Life Support Advisory Committee. Advanced Burn Life Support Course: Provider Manuel. Chicago, IL: American Burn Association; 2007. Available at http://ameriburn.org/ABLSProviderManual 20101018.pdf A characteristic finding in most second-degree burns is that blistering is present. Burn depth is classified as first degree, second degree, or third degree. First-degree burns involve the epidermis only, and third-degree burns involve the entire dermis and adnexal structures. Second-degree burns can be superficial or deep, involving variable amounts of dermis and both types usually have blistering. Deeper second-degree and third-degree burns can be insensate, but superficial second-degree burns are characteristically painful. The clinical relevance of the adnexal structures being preserved in partial-thickness burns is that the ability for re-epithelialization is maintained as these epithelial-lined structures are able to provide a source of keratinocytes in the center of the wound. Burn appearance can guide clinical estimation of injury depth. More superficial second-degree burns will be pink and blanch with pressure. Deep second-degree burns may display fixed staining or pallor similar to a full-thickness injury. Sometimes it is not easy to determine the precise burn depth in a mixed partial-thickness burn. Such burns are referred to as indeterminate depth. In these circumstances serial clinical assessments over several days following injury may be required to determine potential treatment. In such cases laser Doppler imaging may be helpful.1–4 Fig. 21.1 Nomogram for the revised Baux score for mortality following burns. (Reproduced with permission from Williams DJ and Walker JD. A nomogram for calculation of the Revised Baux Score. Burns 41(1), 2015.) Age (years) TBSA (%) Inhalation Injury Inhalation Injury Mortality (%) Revised Baux Score Nomogram Predicted Mortality (%) : Inhalation injury: = NO Inhalation injury: = e-8.8163 + (0.0775 * (Age + TBSA + 17)) 1 + e-8.8163 + (0.0775 * (Age + TBSA + 17)) e-8.8163 + (0.0775 * (Age + TBSA)) 1 + e-8.8163 + (0.0775 * (Age + TBSA)) Instructions: Draw a straight line connecting Age and TBSA Use the appropriate TBSA scale for inhalation injury present/absent Intersection of line with Mortality axis indicates predicted mortality after: Osler T et. al., l Trauma. 2010; 68: 690-7
4. Gill P. The critical evaluation of laser Doppler imaging in determining burn depth. Int J Burns Trauma 2013;3(2):72–77 The model for burn histology involves three areas. The central zone of coagulation is sometimes called the zone of necrosis and is nonviable. This is treated by excision and grafting. The surrounding zone of stasis is initially viable. High-quality, timely treatment can prevent necrosis in this zone and avoid the need for excision and grafting. The zone of hyperemia is sometimes called the zone of inflammation and is viable. No zone of infiltration is present.1
First-degree burns involve the epidermis only and display erythema without blistering. They are commonly a result of sunburn. It is unusual to have to admit or refer a patient with a first-degree burn to the hospital or burn center, even at 15% total body surface area (TBSA) unless pain control is not being achieved. This may be more likely in the pediatric population. Criteria for transfer of patients to a burn center include partial-thickness burns greater than 10% TBSA, third-degree burns, and burns involving the hands, feet, genitalia, perineum, or major joints. Additional criteria include electrical burns, inhalation injury, burns in the context of associated trauma, burn-injured patients with significant preexisting medical disorders, and children, when the hospital does not have the facilities to care for them. Patients with chemical burns should also be referred to a burn center and in particular hydrofluoric acid burns even as small as 1% can be life threatening and hence require immediate referral. Lastly, patients who will require special social, emotional, or rehabilitative intervention who do not meet any of the above physical criteria may be better served by transfer to a burn center.1–3
Hydrogen cyanide (CN) is the gaseous form of cyanide and is generated by the combustion of nitrogen and carbon containing substances, such as wool, silk, cotton, and paper. Therefore, it is likely to occur in subjects exposed to house fires. The cytotoxicity is due to its reversible (not irreversible) inhibition of cytochrome c oxidase, which suppresses cellular respiration and causes tissue anoxia and metabolic acidosis. Elevated CN concentrations are directly related to the probability of death as it causes severe central nervous system (CNS), respiratory, and cardiovascular dysfunction. Toxicity occurs at a level of just 0.1 µg/mL (not 2.0 µg/mL) and by 2.0 µg/mL, death would likely have already occurred. Early administration of hydroxocobalamin 5–10 g intravenously for adults or 70 mg/kg for children is indicated if clinical suspicion of cyanide poisoning is high. This is sold as a preprepared medication (Cyanokit™). An alternative is sodium thiosulfate with sodium nitrite (Nithiodote™). The overall goal of therapy following inhalation injury is to maintain oxygenation while facilitating adequate ventilation. The use of high-flow oxygen is also important; however, 100% oxygen is most indicated in carbon monoxide (CO) poisoning to dissociate CO from hemoglobin (Hb) with which it binds. Other strategies for management of inhalation injury include prevention of barotrauma with low tidal volumes, permissive hypercapnia, high frequency percussive ventilation, and extracorporeal membranous oxygenation (ECMO).1–3
In this case the patient shows signs of myoglobinuria secondary to extensive muscle damage, but not renal dysfunction. This must be carefully treated with fluid therapy to ensure that urine output is maintained between 75 and 100 mL per hour. This aims to minimize myoglobin precipitation and subsequent renal damage. Bicarbonate and mannitol are not contraindicated and, in fact, may be useful in cases of myoglobinuria. The involved limb is at risk of compartment syndrome and a painful, tense limb in the setting of a high-voltage electrical injury should be considered for early fasciotomy. The threshold for fasciotomy is usually an intracompartmental pressure greater than 30 mm Hg, but a decision to operate is made on clinical factors and would be warranted in this case given the clinical presentation. Following a high-voltage injury, there is a significant risk of cardiac arrhythmia and in spite of a normal admission electrocardiogram (EKG), continued cardiac monitoring is required in the acute phase.1–5
In general, chemical burns should initially be managed with copious irrigation. Some chemicals such as phenol require specific treatments such as topical application of polyethylene glycol. Phenol burns have severe local and systemic toxic effects that can result in death with relatively small volumes. Hydrofluoric acid burns release fluoride ions that bind with calcium, leading to profound hypocalcemia. These burns should be treated with calcium gluconate to chelate the fluoride ions. Alkalis should be treated with copious water irrigation, but neutralization with weak acids should be avoided as this can cause an exothermic reaction. Phosphorus should be stained with 0.5% copper sulfate solution or detected with ultraviolet (UV) light and surgically removed. Acid, alkali, and ammonia burns should each generally be irrigated copiously with water only for 15–20 minutes.1–3
burn occurred 4 hours ago. BOX 21.1 THE MODIFIED PARKLAND FORMULA 4 mL/kg/%TBSA burn = Total fluid volume for the first 24 hours from the time of injury. Half of this volume is given in the first 8 hours, and the rest is given over the last 16 hours. 4 mL × 95 (kg) × 42 (%TBSA) = (15,960 mL) or 16 L total fluid volume. Therefore, 8 L is given in the first 8 hours, and 8 L is given over the next 16 hours. The burn occurred 4 hours ago and 3 L was already given. Therefore, the remaining fluid requirement in the next 4 hours is 5 L (1250 mL/hour), followed by 500 mL/hour for 16 hours.1–5
Following burn injury, fluid loss occurs and in more significant injuries, the use of a formal fluid resuscitation process is advocated. The cut off for a resuscitation burn is usually over 10% total body surface area (TBSA) in children and 15% TBSA in adults. Burn shock is typically seen in adults where TBSA is greater than 20% and this will require formal resuscitation. There are a number of different formulae for fluid resuscitation and these include the Parkland formula, the Modified Parkland formula, the Brooke formula, the modified Brooke formula, and the Evans formula. Both the modified Parkland and modified Brooke use crystalloid for the initial 24 hour resuscitation process and are both commenced as soon as possible after the burn injury. The key difference is that the modified Brooke uses less total fluid in the formula calculation and hence reduces the potential for over resuscitation. The Brooke formula is 2 mL/kg/%TBSA, compared with the Parkland, which is 4 mL/kg/%TBSA. For each a total fluid volume is calculated and then this volume is delivered intravenously over the first 24 hours from the time of injury. Half is delivered in the first 8 hours following injury and the remaining half is delivered in the second 16 hours following injury. This means that if a patient arrives in hospital 7 hours after injury without resuscitation, half the total calculated volume would, in theory, need to be delivered in the first hour.1–5
Assessment of burn extent is commonly performed using Lund and Browder charts1 or the rule of nines (Fig. 21.2). The approximate areas are as follows: • Head and neck: 9% • Anterior and posterior trunk: 18% (each) • Lower limbs: 18% (each) • Upper limbs: 9% (each) • Perineum: 1% Alternative ways to assess burn extent include the 1% rule and serial halving. The 1% rule is based on the assumption that the palm and fingers represent 1% of the total body surface area (TBSA). For smaller burns this is a useful approach. Serial halving is useful for a rapid estimation of a large burn and involves making repeated assessments of the burn area stating whether more than half or less than half is involved.2 Fig. 21.2 “Rule of 9” for adults. Anterior Right Upper Extremity 4.5 Palms Anterior Right Lower Extremity Anterior Left or Posterior Left Upper Extremity 4.5 Anterior Left or Posterior Left Upper Extremity Posterior Right Lower Extremity Anterior Chest Posterior Thorax Abdomen Buttocks Face/ Scalp 4.5 Back of Head 4.5 Anterior Posterior
Blood loss during burn excision can be estimated at 0.5 mL loss for each cm2 burn injury debrided. Potential blood loss and the amount of blood available for transfusion both need to be considered when deciding how much excision can be performed in one sitting. The volume of excision achievable will also, however, depend on many other factors and the amount of blood available is only one component. For example, the patient’s premorbid status, the area and depth of burn, the timing in relation to the burn injury, the stability of the patient in the operating room (OR), and the tissue availability to cover the wound. A benefit of fascial excision with respect to bleeding is that blood loss is reduced. However, it does leave a more severe contour deformity and may result in unnecessary removal of healthy tissue. Tangential excision provides a better contour and depth control as tissue is excised until bleeding tissue is identified. However, blood loss is more difficult to control. When excising large burn areas, it is vital to keep the patient warm and resuscitated from a cardiovascular perspective. Systematic staged excision of individual areas can help to minimize heat and fluid loss intraoperatively. The benchmark for grafting is to use the patient’s own skin (autograft) rather than use a cadaver (allograft). This is because cadaveric grafts are only temporary and the graft is rejected 3–4 weeks after reconstruction. Autograft split-thickness skin graft (STSG) is then required at this stage. Other options for temporary burn cover include semisynthetic and synthetic materials such as Biobrane™, Transcyte™, and Integra™.1–6
After a major burn injury, nutritional support is vital to help wound healing. Due to the catabolic state, a caloric to nitrogen ratio of 100:1 is recommended. A patient’s metabolic demands significantly increase after a major burn, but only by 120 to 150%, not by 300%. Enteral feeding is preferred over total parenteral feeds, and prophylactic proton pump inhibitors are recommended to protect the gut which is at risk of stress ulcer formation. Total parenteral feeding may be indicated if there is a sustained period of ileus or some other reason for absorption to be impaired. The Curreri formula is one method of calculating daily caloric needs, but it does not have to be used. Systemic antibiotics are required in the presence of active infection and their selection should be guided by culture sensitivities from wounds, sputum, blood, tissue, or urine. Prophylactic antibiotics are not routinely required. Early debridement and topical antimicrobials are probably more appropriate. Minimizing antibiotics where possible is best in order to avoid bacterial resistance.1–4
The Curreri formula is one method of calculating the required caloric intake after a major burn injury.1,2 The differs slightly for more elderly patients (over 60 years of age), and is reduced to 20 kcal per kg per day + 65 kcal per % total body surface area (TBSA) per day. Although formulas like this are useful tools to guide treatment, care should be taken when they are used because overestimation of caloric requirements is possible. The nutritional plan following burn injury is generally made on an individual patient basis, taking advice from dieticians and nutritionists.
Mafenide acetate is available in 5 and 8.5% forms and has a large amount of data to support its use as an effective topical antibacterial agent. It is particularly useful for treating wounds that are infected with Pseudomonas. Mafenide is a potent carbonic anhydrase inhibitor that can cause hyperchloremic metabolic acidosis and compensatory hyperventilation. In some cases, this can be fatal. Other caveats are that prolonged use of mafenide can promote growth of candida in the wound and it is painful for the patient on application. Silver-containing agents are popular in burn dressings as they have a broad spectrum of cover for both gram- positive and gram-negative organisms. They include silver nitrate and silver sulfadiazine. Sodium hypochlorite also has a broad spectrum of cover, and at concentrations of 0.025% is bactericidal without inhibiting fibroblasts. Manuka honey is popular as a topical antibacterial agent in many wounds including burns. The antibacterial qualities derive in part from generation of bactericidal hydrogen peroxide. Honey has a low pH, creating an environment that also limits bacterial growth and its high sugar content interferes with bacterial cell division and the development of biofilms. Low toxicity of human keratinocytes and dermal fibroblasts has been demonstrated.1–3
Patients with large burns are at high risk of developing sepsis and it is key to identify this early so that appropriate treatment can be instigated. The key signs include hyperventilation, hypothermia or hyperthermia, hyperglycemia, obtundation, ileus, hypotension, and oliguria. Core temperature should normally be around 37° C but can vary according to activity level, site of measurement, and time of day. The normal range for respiratory rate in an adult is 12–16 breaths per minute. A normal random blood glucose should be between 80 and 110 mg/dL (4.3 to 6.1 mmol/L). A systolic blood pressure of 90 mm Hg is normal in many young females, but this is patient specific and can represent a sign of sepsis in many patients. A urine output of approximately 0.5 mL per hour would be normal in this patient. A retrospective review of more than 5000 pediatric patients with a burn injury showed that of the 144 patients who died and underwent autopsy, 47% had sepsis confirmed as the primary cause of death. A further 29% had respiratory compromise as the primary cause of death. Many patients subsequently developed multiorgan system failure as a result. This highlights the importance of recognizing and treating sepsis early following a burn injury.1