35 BURNS
Paulus C. Bauling MBChB, M.Med., FACS

1. Why is it essential to have sound clinical knowledge of urgent and emergent burn care?

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The events of September 11, 2001, have vividly underlined the fact that wars, plane crashes, nuclear and industrial accidents, and many other potential disasters can produce large numbers of burn-injured victims in an instant

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2. How prevalent are burn injuries and deaths from burns?

Roughly, 1.5 million burn injuries occur annually in the United States. Approximately 75,000 of these patients are hospitalized annually. About one half of those hospitalized need the skills of specialized burn centers.
In 1998, 146,941 trauma-related deaths occurred in the United States (population of 270,248,524). This equates to 54.4 deaths per 100,000 people. Of the quoted trauma deaths recorded in 1998, 3813 were burn deaths, representing 1.4 burn deaths per 100,000 people per year. Thus, based on 1998 data, more than 10 people die per day in the United States because of a burn injury.

3. Where do burn injuries occur?

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Eighty percent of burn-related injuries occur in the home, mostly in low-income, multifamily dwellings.

4. Who is at risk of suffering burns?

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The male-to-female ratio for burn injuries is roughly 2:1. The combined annualized death rate for children younger than 5 years and adults age 65 or older is five to six times higher than for the rest of the population.
Work-related burn injuries account for most of the male/female disparity, with accidents in the petrochemical and transportation industries responsible for a significant proportion. Alcohol abuse and illicit drug activity also increase the risk of burn injury and death.
The incidence of burn injuries and deaths in the United States is substantially higher than that of the rest of the industrialized world. Data published in 1995 reveal that New York City (population, 7 million) had more deaths than all of Japan (population, 120 million). The U.S. city of Baltimore, roughly the same size as Amsterdam in the Netherlands, recorded a 13 times higher fire death rate than Amsterdam’s in 1990.

5. Who should provide care for patients with burn injuries?

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This is determined by the severity of the injury and the ability of the provider. All level I, II, and III trauma centers should have well-defined protocols and well-established affiliations with specialized burn centers. A list of these burn centers can be found on the Internet at the American Burn Association’s Web site (www.ameriburn.org) and the American College of Surgeon’s Web site (www.facs.org/dept/trauma).

6. What are the outcomes of the victims of burn injuries?

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Of the roughly 75,000 burn victims hospitalized annually in the United States, approximately 3800 died in 1998, equating to a mortality risk of 7.6%. Pediatric burn centers record mortalities between 2% and 3%. Mortality for those older than 50 years is more than three times higher than the national mean. Above 70 years of age, mortality exceeds one in three victims.

7. Which factors influence burn outcomes most profoundly?

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Using logistic regression analysis on 1665 burn injuries treated in single specialty burn centers, three risk factors were identified with essentially equal weight in predicting mortality. The three factors were burn size of > 40% total body surface area (TBSA), patient age older than 60 years, and presence of inhalation injury to the lungs. The cumulative probability of death when one or more of these factors is presented in Table 35-1.
Table 35-1. MORTALITY RATES ASSOCIATED WITH BURN INJURY

8. Do any other variables influence survival?

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Ethanol abuse and illicit drug abuse can be added to the three factors listed above, increasing the risk of death by a factor of two to four times.

9. As a single mode of injury, why do burns pose such a devastating challenge and threat to victims?

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* Extensive damage to the skin (considered the largest single organ in the body and consuming almost 20% of the cardiac output) sets the stage for bacterial invasion.
* Because humans are almost 70% water, enclosed by a complex integumentary system, serious derangements in fluid homeostasis occur when the skin envelope is destroyed.
* Heat-induced denaturation of integumentary proteins enter the circulation. Systemic infection or sepsis remains the dominant precipitant of organ failure and death; this points to a burn injury-related immune dysfunction or failure.

10. What happens to the body of a burn victim?

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The pathophysiologic damage is both local and systemic.

11. What happens locally?

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The injury site may be divided into three zones by standard light microscopy: an inner zone of necrosis, a middle zone of stasis, and an outer zone of hyperemia. In the zone of necrosis, all proteins are denatured; all microvascular and macrovascular structure and function are destroyed. Surrounding this central zone is a zone of stasis. Here, cellular morphology is intact but cells are swollen with microstructural changes with extravasation of leukocytes and red blood cells into the interstitial space, increased interstitial fluid, and capillary stasis. A third zone of hyperemia then gently transitions into the adjacent normal tissues where no abnormalities are seen.

12. What changes occur systemically?

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Systemic events become clinically significant beyond an injury size of 10% TBSA. Two important abnormalities occur: (1) a trend to fluid retention with generalized edema, caused by an increased systemic microvascular permeability of very rapid onset (minutes to hours) and (2) a definite and reproducible decrease in cardiac output that gradually resolves over 12-36 hours to evolve into an ensuing cardiovascular hyperdynamism at 36 hours postinjury. To summarize, the pump is failing, and the microvasculature is leaking.
KEY POINTS: FACTORS STRONGLY ASSOCIATED WITH MORTALITY AFTER BURN INJURY

1. Burn size > 40% TBSA
2. Patient age > 60 years
3. Presence of inhalation injury
4. One risk factor: 3% mortality rate; all three risk factors: 90% mortality rate

13. How can burn victims be managed in a rational way from the time of injury?

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Five phases of care can be identified:

1. Burn first aid
2. Prehospital care
3. Emergency department
4. Transport to burn unit
5. Stabilization in burn unit or patient room

14. What can first responders do when witnessing a burn injury?

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First, do no harm. No ice, butter, dry ice, or any other substance should be applied to the wound after extinguishing the fire. Instead, focus on caring for the patient’s needs. If the burn is minor (< 10% TBSA), running tepid tap water over the burn with a hand-held shower for 20 minutes is beneficial. The time and effort required to apply wet soaks with towels appears to provide no benefit and may provoke hypothermia. If stranded in a remote area, encourage oral fluid intake and cover the wound with clean towels. Aspirin or ibuprofen may benefit the patient and the wound. Elevate any burned extremities and encourage full range of motion of all joints.

15. What actions are needed from prehospital providers (i.e., after the prehospital crew arrives, what are their priorities)?

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The American College of Surgeons’ Committee on Trauma (ACS-COT) advises that all ambulance crews follow “scoop and run” procedure guidelines for all burn victims within 60 minutes of an appropriate hospital (level I or II trauma center or burn facility). Attempt to place an intravenous (IV) line en route, but this is not essential if the travel time is < 60 minutes. Lines may be placed through burned skin, preferably in antecubital veins.
16. How does the hospital-based emergency department contribute to the care of the patients with major burns? Show answer
Urgency in caring for the victim, not the wound, is pivotal for the ultimate survival of the victim:

A Airway-Look for soot in the pharynx and for extensive facial burns.
B Breathing-Identify hoarseness, or stridor. Listen for breath sounds on both sides.
C Circulation-Place two peripheral IV lines, start fluids as lactated Ringer's solution; calculate the Parkland formula = 4 mL × kg body weight × % body burn [half of volume in first 8 hours; other half over 16 hours].
D Neurologic deficit-Examine central nervous system (CNS) and cranial nerves; assess the neurologic status of burned extremities.
E Expose and examine the skin, log roll and meticulously determine burn size on the posterior body, and then cover and preserve body heat. The patient's environment should be heated to 90°F.
F Fluid therapy should be assessed for effect as demonstrated by 1 mL of urine output per kilogram of body weight every hour.

Pain management and psychoemotional support are also vitally important. Avoid overdosing with narcotics.

17. What initial yardstick determines the severity of a burn injury?

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Burn wound size, which is expressed as a percentage of the total body surface, determines the severity. Remember that the Parkland formula for fluid resuscitation uses the burn wound size to calculate the volume of resuscitation. Therefore, overestimation of burn size leads to overestimation of fluid requirements, which may lead to excessive edema (including such unwanted outcomes as abdominal compartment syndrome). Underestimation of burn size may lead to persistent shock.
Contrary to popular belief, the depth of a burn injury has much less impact on the severity of the injury. The depth of injury also remains an area in which accurate clinical diagnosis, even by experts, is lacking. Burn depth, however, does determine whether a wound will heal on its own or whether skin grafting has to be done.
18. How are burns sized? Show answer
This determination is done clinically, with the aid of three important clinical tools:

1. The volar surface of the victim’s opened hand (including fingers) = 0.8-1.0% of TBSA; most useful for the sizing of small, scattered wound areas
2. Rule of nines: most commonly used; easy to memorize; not very accurate; usually overestimates
* Adult head = 9%
* Total upper extremity = 9%
* Total lower extremity = 2 × 9%
* Anterior torso = 2 × 9%
* Posterior torso including buttocks = 2 × 9%
* Genitals = 1%
Note that adults and children differ significantly by the difference in the relative size of the head (9% in adults, 15% in infants). By contrast, a thigh in an infant is much smaller than in adults (6% versus 10%).
3. Lund and Browder chart: more accurate; time consuming; requires practice; not easy to memorize

19. Besides the actual skin injury, what other associated injuries may occur?

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Inhalation injury is diagnosed in ± 10% of all hospitalized burn victims. Other physical trauma is frequently associated with explosions or merely the attempts to escape the fire. Awareness of associated trauma justifies the importance of a careful Advanced Trauma Life Support (ATLS)-guided trauma evaluation.

20. How is inhalation injury defined?

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In contrast to the visible and somewhat quantifiable external burn injury to the skin, the inhalation of heat, carbon monoxide (CO), cyanide, and other toxic or noxious vapors is less visible and less quantifiable, yet very dangerous. Four separate mechanisms of injury to the airways are sometimes incorrectly grouped as inhalation injury:

1. CO intoxication: CO is a product of incomplete combustion of organic or synthetic materials. CO has a 250 times greater affinity for hemoglobin than does oxygen, causing a decrease in blood oxygen content with possible hypoxic neurologic, cardiac, and kidney damage. Levels around 5% are routinely found in cigarette smokers, burn victims become symptomatic around 15-20%, and life is threatened around 30%. Management is by administration of 100% oxygen, which reduces the half-life of carboxyhemoglobin from 200 to 40 minutes.
2. Heat damage to upper airways: Although building fires can reach temperatures of 1000°F, the countercurrent mechanism of blood flow in upper air passages that normally helps us warm very cold air in the winter is equally capable of cooling down the air to temperatures > 100°F. However, prolonged breathing of superheated air or steam provokes damage to the naso-, oro-, and laryngopharynx and, most critically, the vocal folds. Even minimal vocal-fold edema presents as altered phonation or hoarseness and may rapidly progress to stridor, acute laryngeal edema, asphyxia, and death. Therefore, patients with altered phonation (see question 21) need immediate endotracheal intubation. Intubation is then usually necessary for 2-3 days or until airway edema has subsided.
3. Inhalation of toxic smoke components that are produced by the combustion of modern synthetic materials used in the interior decoration of houses, buildings, and cars. Examples include plastics, vinyl, paints, carpets, synthetic fabrics, and floor tiling. The overall mortality from this kind of injury (for which the term parenchymal inhalation lung injury could be more descriptive and appropriate) approaches 50%. The ultimate effect of the inhaled toxins is direct damage to airway mucosa, necrosis of mucociliary brush border, and death of surfactant-producing type 2 alveolar pneumocytes, leading to pulmonary failure.
4. Cyanide poisoning: The combustion of many synthetic materials also produces cyanide gas, which binds to the cytochrome enzyme system and inhibits mitochondrial function and cellular respiration. Blood cyanide levels should be assessed in all patients with CO levels > 10%. A toxicology center should be contacted. Sodium nitrite is usually administered intravenously, followed by IV sodium thiosulfate.

21. How is inhalation injury diagnosed and managed?

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It is diagnosed and managed with the following five entities:

1. Obvious hoarseness or stridor
2. Substantial head and neck or facial burns
3. Entrapment in enclosed space or direct proximity to an explosion
4. Extensive total body burns (> 50% in young adults; less in elderly individuals)
5. Event history of superheated steam

In the absence of these findings, immediate airway intervention (intubation) is not warranted, because endotracheal intubation immediately sets the stage for other respiratory complications, including pneumonia. Laryngoscopy or dynamic pulmonary function testing (flow-loop) may be helpful but are not essential or of definitive value. Repeated clinical assessment (e.g., respiratory rate, progressive hoarseness, use of accessory muscles) is more helpful than special tests. Sit the patient up as soon as possible, when stabilized, to help limit edema in head and neck and airway.
The diagnosis and management of CO poisoning rests on the blood level of CO, but all victims of dwelling fires should receive 100% oxygen through a non-rebreathing mask until the CO level is documented < 10%. Levels > 15% justify endotracheal intubation with 100% oxygen. The diagnosis of smoke inhalation is determined by the event history (e.g., when the victim has been trapped in an enclosed space for a significant period of time). The presence of soot in the mouth or in expectorated sputum is not diagnostic in itself. Significant smoke inhalation mandates endotracheal intubation. CO levels are critical, as well as a cyanide level, if the CO level is > 10%.

22. What treatment has most influenced the outcome of burn victims over the past 100 years?

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Adequate and timely fluid resuscitation.

23. Why should fluid be resuscitated, and by what route?

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All patients with burns > 10% TBSA should receive fluid. Fluid resuscitation through the gastrointestinal tract with an orogastric tube is used quite often in pediatric burn centers. In adults, the IV route is mandatory.

24. How is fluid therapy managed?

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The fluid management plan has two components. First, determine the burn wound size and the patient’s weight in kilograms, calculate the hourly fluid rate by the Parkland formula, and administer lactated Ringer’s solution at the hourly rate calculated.
The second component of the plan is just as important. Monitor the effectiveness of your fluid therapy plan and adjust it promptly when indicated. Our goals are a hemodynamically normalized individual, with a urine output of 0.5-1.0 mL of urine per kilogram body weight per hour. Avoid bolus therapy. Simply adjust your hourly rate. Be aggressive when you have to increase the hourly rate and very cautious when you decrease it in response to excessive urine flow.

25. What should be done if this treatment algorithm fails to achieve clinical improvement and patient stabilization?

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Failure to respond to the Parkland formula is indicative of a poor prognosis. However, some additional measures may be beneficial but are not currently considered as part of the standard of care. These include the use of hypertonic saline solutions in massive burns, early use of colloids in massive burns, and the early use of inotropes (dopamine is preferred in most burn texts). Finally, at least two prospective studies have failed to show benefit of invasive cardiac monitoring in the absence of preinjury cardiac disease.

26. How are fluid requirements calculated when there has been a delay in the initiation of therapy?

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Sometimes delay is unavoidable. In an attempt to address a perceived backlog of fluid resuscitation, current teaching is to proportionally increase the fluid volume in an attempt to get the desired total volume for 8 hours into the patient before the 8-hour period elapses. This remedy does require some common sense-one should not apply this guideline if the patient arrives at the resuscitation site later than 3 hours after the injury. Instead, administer fluids based on blood pressure, pulse, and urine output.

27. What is the best way to care for burn wounds initially?

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Early on, these wounds need simple coverage with a surgically clean or, if available, sterile sheet or surgical drape. The ACS-COT burn and trauma guidelines state that definitive wound care need not occur up to 24 hours postinjury. No ointment or specific antibacterial treatment is initially required. The patient should be kept warm because exposure precipitates systemic hypothermia.
For definitive wound care, the entire patient is washed or showered, and residual debris and damaged epidermis are removed. Then the extent of the injury is mapped, usually on a Lund and Browder chart, along with very preliminary attempts to determine the depth of the injury. A burn wound is usually a mosaic of different areas injured to varying degrees (depths). All burn wounds deepen to some extent over the first 48-96 hours, so a better prediction of which areas require grafting will come with time.
If appropriate wound care is applied, healing should occur within 14-18 days in areas where germinal cells are present in sufficient numbers. Wherever an area of burn injury is identified as a full-thickness injury, healing will never occur; these areas require skin grafting.

28. Why and how is the depth of a burn injury graded?

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This depends on the presence of skin appendages (hair follicle and sweat gland) that carry the germinal layer deep into the dermis, from which re-epithelialization can occur. On the day of injury, the visual ability to differentiate burn wound that will heal from that which will not is poor (50% accurate). Over time (next 3-7 days), the accuracy of clinical prediction will improve somewhat (≤ 90%). The following table helps to elucidate these aspects. (See Table 35-2.)
Fourth-degree burns involve damage to structures deeper than the dermis (e.g., fat, muscle, bone, tendon, nerve, joint capsule). Burns are designated as fifth degree when tissue is lost, blown off, or vaporized by the burn or blast.

Table 35-2. DEPTH OF INJURY WITH CLINICAL SIGNS AND PROBABLE OUTCOME

29. When should surgical excision of the burn wound begin?

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It should start as soon as possible, but it should be blended with common sense and pragmatism, which implies a hemodynamically “normalized” patient with no signs of sepsis or other contraindication to major surgery. This can be as soon as 24 hours after injury in small to moderate size burns (≤ 30% depending on age) but may take up to 4-10 days in unstable, septic, or frail patients. The overall goal remains to remove the infected or necrotic burned tissue as soon as possible without unduly stressing the patient. It is better for the patient to have a large surgically created wound than a wound containing large amounts of burn-damaged tissue exuding proinflammatory cytokines. Excisional strategies include staged excisions in several sessions, not exceeding 2 hours of operating time. Some authorities stop excising tissue as soon as 75% of the patient’s blood volume has been transfused. Burn wound excision can be a huge physiological stress, but is vastly safer than any alternative.

30. How is the excised area managed?

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A significant advance in burn management occurred in the early 1970s when Janzekovic demonstrated that excised wounds should be immediately grafted with skin. This remains the goal. If donor sites are insufficient, cadaver skin, pigskin, or biosynthetic products (e.g., Integra, Biobrane, or Transcyte) can be used for wound coverage. These areas require autografting subsequently. Cultured autologous keratinocytes are an attractive theoretical alternative, but they still lack consistent high-percentage engraftment when used on large areas.

31. What is the impact of a severe burn injury on the body?

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A big burn is on the top of the list of diseases or injuries that are best avoided. The metabolic response peaks at 2.5 times the basal metabolic rate (BMR) in all burns > 50% TBSA. This maximal acceleration of the body’s metabolism by burn injury leads to rapid and severe catabolism, further aggravated by periods of septicemia as well as heat loss through increased evaporation. Recent evidence suggests that growth hormone (HGH) therapy may have benefits in massively burned patients, but problems with glucose control are substantial during HGH-therapy. Several recent studies have also demonstrated the benefit of using beta-adrenergic receptor blockade (metoprolol) early in burns, with substantial benefits toward ameliorating the hypermetabolism.

32. How can we best supply fuel to the metabolic furnace of the body?

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Nutritional support of the burn victim is paramount. However, the total reliance on the gut as the primary route of nutritional support (as opposed to IV nutrition) has been slow to achieve acceptance. Total enteral nutrition may have the added benefit of maintaining the intestinal barrier function, which is purported to reduce septic events by preventing bacterial translocation. Currently, the concept of immuno-nutrition is in vogue, but it is fraught with intense controversy surrounding the role of glutamine and, more especially, arginine.

33. What major life-threatening complications may occur during the healing period?

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Septicemia, sepsis or septic shock, pneumonia, multiple organ dysfunction, and multiple organ failure.

34. What is the role of antibiotics in burn care?

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Antibiotics are never administered prophylactically for burn injuries. Fewer than 10% of all burn injuries require systemic antibiotics during the entire course of treatment. However, early and appropriate antibiotic therapy is a critically important and life-saving tool in the management of established infections in burn patients. The key to appropriate antibiotic therapy is the early diagnosis of an infective or septic event and wise selection of the appropriate drug or drugs based on the unique infectious profile of the burn victim. The antibiotic selected must be adjusted after culture and sensitivity information becomes available.
One real dilemma of burn care, however, is that a raised core body temperature does not always indicate infection or sepsis. It is important to view abnormal temperature readings in conjunction with other aberrations in clinical, biochemical (C-reactive protein; procalcitonin), and microbiologic data. Such warning signs include sudden changes in hemodynamic parameters, mental status, general appearance of the patient (he or she suddenly looks ill or is unwilling to cooperate), arterial blood gas changes, sudden intolerance of enteric feeding, thrombocytopenia, glucose intolerance, and oliguria.
35. How are chemical burn injuries approached? Show answer
Brush off all chemicals that remain in powdered form on the victim. Thereafter, immediate and prolonged irrigation (30 minutes) of the contaminated skin should be done with running tap water; in the case of alkali burns, irrigate for 60 minutes. Some chemicals may be absorbed; therefore, immediate contact with a toxicology center is indicated.

36. How are patients with electrical burns managed?

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An injury caused by electricity may either be an electrical flash burn or contact or conduction injury. In electrical flash injury, the air or atmosphere is ionized by the electrical discharge, without conduction of current through the body. Thus, the injury is only cutaneous. A true electrical flash burn most frequently heals without much grafting. Airway compromise is rare. In electrical conduction injury, however, tissue is damaged through the actual transfer of electrical energy through the patient from entry point to exit. Thermal energy is generated within the tissues because of the relative resistance to the conduction of current, with resultant protein denaturation and cell death. Different structures (e.g., bone, skin, muscle, nerve, tendon, lung) exhibit different electrical conductivity, resulting in unpredictable conduction pathways. Thus, the skin is often only minimally involved at the entry and exit sites, with extensive muscle, nerve, tendon, and even bone necrosis in erratic patterns. Neurologic injury, compartment syndrome, and myoglobinuria are frequent complications. Rapid tissue decompression (i.e., fasciotomy) is essential with early and repeated reexploration to remove necrotic tissue. The goal of fluid therapy should be to achieve high urine volumes (> 1.0-1.5 mL/kg/h). Alkalinization of the urine is also beneficial.

37. After burn injuries have healed, what important issues remain to be addressed in the rehabilitation period?

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The rehabilitation of a burn victim must begin on the day of admission and is a total team effort that involves physiatrists, plastic surgeons, occupational therapists, physical therapists, nutritionists, psychologists, social workers, pulmonologists, microbiologists, pharmacists, speech therapists, and nurses. Rehabilitation of the mind and body must occur in concert.

38. Are burnt children just small adults with burn injuries?

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No. Children really are different, so a pediatrician should be consulted.

39. Does this chapter provide a complete review of contemporary burn care?

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No, this is just an overview. Please review the bibliography below. Injury by lightning, ionizing radiation, and cold also warrant special attention.

References
WEB SITE
http://www.ameriburn.org/

BIBLIOGRAPHY
1. Demling RL: Burn care in the immediate resuscitation period. In American College of Surgeons: Surgery: Principles and Practice. Chicago, American College of Surgeons, 2002.
2. Gibbons J: Prevention. In Gibbons J (ed): Fire! 38 Lifesaving Tips for You and Your Family. Seattle, Ballard Publishing, 1995, pp 15-64.
3. Heyland DK, Novak F, Drover JW, et al: Should immuno nutrition become routine in critically ill patients? JAMA 29:944-953, 2001.
4. McDonald-Smith GP, Saffle JR, Edelman L, et al: National Burn Repository 2002 Report. Chicago, American Burn Association, 2002.
5. McGill V, Kahn S, Gamelli RL, et al: The impact of substance use on mortality and morbidity from thermal injury. J Trauma 38:931-934, 1995. Medline Similar articles Full article
6. Pruitt BA, Goodwin CW, Mason AD Jr: Epidemiological, demographic and outcome characteristics of burn injury. In Herndon DN (ed): Total Burn Care, 2nd ed. London, W.B. Saunders, 2002, pp 16-33. Full article
7. Ryan CM, Sheridan RL, Tompkins RG, et al: Objective estimates of the probability of death from burn injuries. N Engl J Med 338:362-368, 1998. Medline Similar articles Full article