Burns

*Increasingly, early colloid infusion (generally 5% albumin) is being used in patients with very large burns, particularly if they are young or resuscitation is not going smoothly. It is the routine practice of this author to substitute 100% of a calculated maintenance rate and provide this as 5% albumin, subtracting this from the formula’s predicted crystalloid need in patients with burns exceeding 30% of the body surface. This maneuver seems to minimize morbidity related to edema.






Late Post-Injury Physiologic Alterations


Wounds are not physiologically static. Clinically impor­tant changes occur as a result of microvascular thrombosis, colonization, and infection. These changes can be favorably influenced by effective resuscitation and wound management.


Late local wound issues are particularly important in patients with extensive soft tissue damage, such as those with burns or extensive crush injury, as infection of large volumes of devitalized tissue can quickly overwhelm the body’s innate ability to contain sepsis. Wounds are initially clean but are rapidly colonized by endogenous bacteria. As these bacteria multiply in necrotic tissue over the succeeding days, proteases liquefy the eschar and the necrotic material separates, leaving a bed of granulation tissue. In healthy patients with smaller burns (<20% of the body surface), this septic process is usually tolerated. When injuries are larger, systemic infection results, explaining the rare survival of patients with burns in excess of 40% of the body surface managed without early wound excision.


Patients with large burns initially demonstrate a decrease in cardiac output and metabolic rate, which usually responds to fluid resuscitation. In those successfully resuscitated, a hypermetabolic response follows, with a near doubling of cardiac output and resting energy expenditure over the next 24 to 48 hours. The magnitude of the response increases with burn size, peaking as high as twice the normal basal metabolic rate in otherwise healthy patients with burns involving 60% or more of the body surface at area. The hypermetabolic response is characterized by enhanced gluconeogenesis, insulin resistance, and increased protein catabolism.13 The etiology of these physiologic changes is not well understood but is thought to involve a change in hypothalamic function with coincident increases in glucagon, cortisol and catecholamine secretion, bacterial contamination of wounds with systemic release of bacterial products, and gastrointestinal barrier dysfunction with translocation of bacteria and their byproducts. These changes have major practical implications for the support of seriously burned patients, most notably through provision of adequate nutrition.


Safe and reliable modification of adverse components of the hypermetabolic response, particularly protein catabolism, has remained an elusive goal.14 Several tactics have been tested, and some are now employed, but none has been universally adopted as a standard of care. Notable interventions have included antipyretics, β-adrenergic antagonists and agonists, nonsteroidal anti-inflammatory agents, recombinant growth hormone, insulin-like growth factor-1, and anabolic steroids. Available data seem inadequate to support the routine use of such therapies. Prompt and effective control of the wound remains, by far, the most reliable intervention to control this physiology.


As tissue hypoxia and wound contamination drive the response, the most effective interventions deal with these issues directly. Resuscitation and decompression will minimize early tissue ischemia. Beginning in the 1970s, the advantages of early excision and closure of small burn wounds were reported to include truncated hospital stays and enhanced functional outcomes. In the decades that followed, this strategy was then applied in the treatment of patients with large burns, resulting in shorter hospital stays and enhanced survival. Early excision of necrotic or ischemic tissue will minimize the incidence of wound contamination and systemic sepsis and inflammation.




Practical Considerations in the Care of the Burn Patient


Injured patients at the extremes of age bring with them a number of important anatomic, physiologic, and psychosocial issues that directly impact their care. These issues are listed in Box 37.3. Anticipation of these differences facilitates optimizing patient outcomes.15


 



Box 37.3


Anatomic, Physiologic, and Psychosocial Considerations at the Extremes of Age



Pediatric Considerations



The much smaller pediatric upper airway is rapidly occluded by progressive edema.


The trachea of the young child is short, making mainstem intubation common.


Bronchospasm is commonly a problem for young children after inhalation injury.


Young children have less mature renal concentrating ability.


Young children are easily fluid loaded.


Young children are particularly susceptible to hyponatremia and secondary cerebral edema.


Young children have higher energy needs per unit body weight.


Children tolerate long periods of inadequate nutrition poorly.


The large surface area to mass ratio makes temperature control more difficult.


Children’s skin is thinner skin than that of adults.


Burns are relatively deeper, and donor sites more unforgiving.


Children have smaller vessels compared with adults.


Children grow and will predictably outgrow good surgical results.


Children seem to form hypertrophic scar with greater intensity.


Pain and anxiety are more difficult to access.


School age children have schooling needs.


A dysfunctional family environment may compromise children’s recovery.



Geriatric Considerations



Injury mechanisms more often involve compromised mobility or dexterity.


Injuries may reflect an inability to safely live alone.


Injuries occur during syncopal episodes.


Resuscitation should be carefully considered if burns are very large, particularly in the presence of inhalation injury.


Patients may have advanced directives, interested families, or health care proxies who should be consulted as early as possible in their care.


Older adults often do not have the physiologic reserve of the young.


Pulmonary function may be compromised by years of smoking.


Occult or overt coronary artery or peripheral vascular disease may exist.


Muscle strength, including respiratory muscles, may be reduced.


Renal function may be reduced with resulting greater sensitivity to nephrotoxic drugs or hypotensive insults.


Nutritional needs of older adults are poorly predicted by standard predictive equations.


The skin of the older person is thin and therefore sustains full-thickness injury more readily and tolerates repeated donor harvest less well.


Older adults may live alone or have a spouse who cannot reasonably meet post-discharge needs.


Discharge planning may be very complex and therefore must be started early.


A constant early concern in management of burn patients is the missed injury. In the chaos of initial care of those who are seriously injured, important associated injuries can be missed, resulting in significant morbidity. Burn programs are unique because of the long duration of multidisciplinary follow-up care generally provided to patients. Taking a long-term perspective on the course of injury from the outset greatly facilitates setting realistic goals and expectations with the team, the patient, and the family.



Prehospital Care and Interhospital Transport


Field and transport priorities begin with control of the airway, securing venous access, placement of bladder and nasogastric catheters, maintenance of body temperature, fluid administration if transport time will be more than 1 hour, documentation of the events of the injury from personnel who will not be available to the receiving facility, efforts to notify family members and to define the legal custodian of children, and clear documentation of all interventions. Hypothermia is a particular problem in burn patients because of evaporative heat losses. Transport vehicles and emergency receiving areas should be heated before the patient’s arrival. Initial burn dressing should be dry, clean sheets, rather than wetted dressings. Immediate cooling of a wound involving less than 10% of the body surface may help limit burn depth without causing systemic hypothermia. However, by the time emergency response personnel have arrived at the scene of injury, this window of opportunity has usually passed.



Phase One – Initial Evaluation and Resuscitation


A relatively rigid organized approach to initial evaluation of burn patients is useful and is described by the Advanced Burn Life Support Course of the American Burn Association.16 The primary survey is an initial pass at the patient looking for major aberrations in airway, circulatory, or neurologic status that justify urgent intervention. Intubations are done, if indicated. Clinically obvious pneumothoraces are decompressed. Emergent vascular access is obtained. A very brief neurologic assessment is made. The patient’s body is exposed for complete examination.


The secondary survey includes a detailed head-to-toe physical examination following hemodynamic normalization of the patient. Limited laboratory studies and directed imaging are done. The fundamental goal is to consider carefully the injury mechanism and to exclude all potential occult injuries before doing a detailed assessment of the burn. Computed tomography (CT) of the head, chest, abdomen, and pelvis is justified if the mechanism of injury is consistent with head or abdominal trauma. High-energy injuries such as those caused by electrical burns, motor vehicle crashes, and blasts are notorious for generating significant injuries missed during the initial evaluation.


The tertiary survey is a planned repeat physical examination 1 to 2 days after admission. Focused imaging is often a part of this process. The goal is to exclude subtle injuries that might have been overlooked initially.


An essential component of initial burn care is to find and rectify compartment syndromes before irreversible tissue ischemia occurs. Inelastic near-circumferential burns or the normal fascial envelopes of muscle groups can result in high soft tissue pressure if underlying tissues become edematous by direct injury or secondary capillary leak and edema. Extremities should be assessed for temperature, pliability, voluntary motion, pain with passive motion, named vessel pulsations, and low-pressure flow by using capillary refill and Doppler signals in the digital vessels and digital pulp. Serial compartment pressures may be valuable in selected patients, but serial clinical examination suffices to determine the need for escharotomy or fasciotomy in most situations. These extremities should be promptly decompressed via escharotomy and/or fasciotomy before the development of irreversible tissue necrosis (Fig. 37.1). Infrequently, abdominal pressures become elevated with resultant increasing airway pressures, oliguria, and hypotension. This should be promptly rectified by abdominal decompression, which can be done in the intensive care unit. Although rare, retrobulbar hypertension should be suspected in the presence of deep facial burns and responds well to lateral canthotomy, which is discussed in the following section.


image

Figure 37.1 When subeschar edema results in dangerously high soft tissue pressures, escharotomy and/or fasciotomy should be done before the development of irreversible tissue necrosis. In this patient, both have been done through the same incision. 

Fluid resuscitation of burn patients has evolved substantially in recent years, in part as a result of lessons learned in Southwest Asia by military providers. During the first 18 to 24 hours after a serious burn, patients with larger burns manifest a diffuse capillary leak that increases with injury size, delay in initiation of resuscitation, and the presence of inhalation injury. The clinical objective is to administer adequate, but not excessive, fluid while ensuring that soft tissues are not rendered ischemic beneath inelastic eschar or tight fascial envelopes. While weight-based and burn size–based formulas have been developed over the years, none is reliably accurate in individual patients. A consensus approach is described in Box 37.2. Close physiologic monitoring with titration of infusions to meet resuscitation endpoints such as urine output, base deficit, and vital signs is required to achieve accurate, individualized resuscitation.


Capillary integrity generally normalizes at 18 to 24 hours, and fluid needs then approach approximately 150% of maintenance in most patients. Overadministration of fluid should be avoided at this phase of resuscitation.



Phase Two – Initial Excision and Biologic Closure


Phase Two focuses on identification and excision of full-thickness burns. This maneuver minimizes the occurrence of wound and systemic sepsis and should be completed before wound infection develops, generally within 5 to 7 days of injury. This phase of care often requires critical care that is generally directed by the burn team. The concept of early wound excision is important to the care of patients with significant burns and crush or other soft tissue injury that generates a burden on necrotic tissue. Excisional surgery for deep burns historically was associated with significant blood loss, but by using thoughtful technique, blood loss can be minimized and well tolerated.


Extensive burns can incite a hypercoagulable state, and burn shock is associated with splanchnic ischemia. Consequently, seriously burned patients are prone to deep venous thrombosis and pulmonary embolism. Selected use of pharmacologic and mechanical prophylaxis measures is common among burn units, although specifics will vary.



Phase Three – Definitive Wound Closure


Phase Three involves definitive wound closure; replacing temporary membranes, such as human allograft, with permanent autografts; and closing small but complex wounds such as those on hands and face. The duration of this phase varies according to injury severity but is usually complete at the time of acute hospital discharge. During this phase of care, rehabilitation efforts intensify and the patient is generally weaned from the need for intensive care.



Phase Four – Rehabilitation and Reintegration


Phase Four describes the process of reconstruction, rehabilitation, and reintegration. This phase of care frequently bridges the transition to the outpatient environment and can be lengthy, involving multiple readmissions for staged functional and aesthetic reconstruction, depending on injury pattern and severity. Continuous engagement of the burn team is ideal from the inpatient to the outpatient phases of care. Burn physical and occupational therapy is an essential component of recovery for burn patients.17 This begins with daily ranging, splinting, and antideformity positioning and progresses through active motion, strengthening, and mastery of activities of daily living. The family environment is an important therapeutic consideration.18 Family engagement and support through the process of recovery is ideal.



Burns of the Head and Neck, Face, and Ocular Adnexa


Acute Evaluation and Management of Head and Neck Burns


The head and neck have functional and aesthetic importance out of proportion to their surface area. A cautious conservative approach to wounds of the scalp, face, ears, ocular adnexa, and neck is commonly adopted by most experienced surgeons. At all times, a long-range view should be taken with the objective of optimizing ultimate function and appearance, even if it delays wound closure or results in increased donor site morbidity because of the desirability of thicker grafts.



Burns of the Scalp


The scalp is large, representing more than 10% of the body surface in a small child. The density of deep hair follicles often results in spontaneous resurfacing of mid-dermal and deep dermal burns. This anatomy supports initial conservative treatment of most scalp burns and the use of the scalp for split-thickness donor harvest. Shaving a burned scalp will facilitate cleansing and topical wound care.



Burns of the Face


Early management of facial burns can have a major influence on ultimate facial function, appearance, and reconstructive options. The face represents only 4% of the body surface, which is nearly insignificant physiologically, opening up the option to take an initial conservative approach to all but the deepest of facial burns (Fig. 37.2). It is rare for infected facial burn wounds to be the source of overwhelming systemic sepsis. The central face is rich in sweat and sebaceous glands and when these burns are managed without acute excision, resurfacing can produce pleasing results.19 This is especially true in the bearded area of adult males.


image

Figure 37.2 The face represents only 4% of the body surface, and overwhelming facial wound sepsis is quite uncommon. This opens up the option to take an initial conservative approach to all but the deepest of facial burns. The central face is rich in sweat and sebaceous glands, so even skin with deep second-degree burns will often resurface with quite pleasing results when these burns are managed without acute excision. It would be expected that burns such as these will heal well with a topical care program and no grafting, although follow-up scar management might be required. 

Many topical care plans are appropriate for the treatment of facial burns. The face is richly vascular, so partial-thickness burns will quite often heal as long as desiccation and infection are avoided. A large variety of topical medications and membranes are appropriate, and none is unequivocally superior to another.20 Clearly superficial burns are often treated with hygiene using bland soap and water and open application of antibiotic ointments, refreshing them every 6 to 12 hours. Deeper burns are often treated with topical silver sulfadiazine–impregnated gauze, which is cleaned and changed daily. Increasingly, membrane dressings that release silver are applied to second-degree burns, as they require less frequent changes, although this is difficult to do well on the face in many cases. Periodic gentle removal of necrotic debris and prevention of desiccation are common requirements in all successful management plans. Burns around the eyes can be dressed with topical ophthalmic antibiotic ointments. In the presence of facial burns, devices to secure oral or nasal endotracheal and enteral tubes should not place pressure on the burned nasal septum or ears (Fig. 37.3).


image

Figure 37.3 In the presence of facial burns, devices to secure oral or nasal endotracheal and enteral tubes should not place pressure on the burned nasal septum or ears. This should be monitored regularly. 

In all but the deepest of facial burns, it is common and prudent practice to treat the wounds topically and delay any excision and grafting until the full-thickness components are unequivocally clear.20 There has been some debate over the years about grafting the face in cosmetic units. This is appropriate if it does not require the sacrifice of significant areas of healed burn or unburned skin. Areas of the face that need to be grafted are ideally resurfaced with thick split-thickness grafts of optimal color match. Optimal facial donor sites are best identified early in the course of the patient’s condition so that they can be preserved for this purpose. Facial burn excisions are done in a careful, layered fashion. Subeschar clysis with dilute epinephrine should be used liberally to minimize bleeding.21 The head of the operating table should be kept elevated. A critical component of the operation is to craft a dressing that absolutely protects against graft shear (Fig. 37.4). After the grafts have vascularized, massage and pressure therapy should begin. Patients with deep facial burns can have very pleasing functional and aesthetic outcomes, but it is important that they stay engaged with the burn team over time to achieve these results. The impact of small tension-relieving operations and laser-based interventions may improve results while decreasing morbidity.22 In very rare circumstances, facial transplantation may be considered.23,24 With careful, staged reconstruction, the large majority of patients with even very destructive facial burn injuries can achieve quite acceptable long-term functional and aesthetic results (Fig. 37.5).


image

Figure 37.4 An essential part of grafting facial burns is crafting a dressing that will reliably prevent shearing at the graft–wound interface. 

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

May 14, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Burns

Full access? Get Clinical Tree

Get Clinical Tree app for offline access