Burns associated with wars and disasters

Jonathan B. Lundy, Leopoldo C. Cancio

US Army Institute of Surgical Research, Fort Sam Houston, TX, USA

Note: The opinions or assertions contained herein are the private views of the authors, and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.

Introduction

Military operations and civilian mass casualty disasters provide among the most difficult scenarios in burn-patient management. At the same time, they historically have also led to changes in care. The purpose of this chapter is to review experience with burn care during current combat operations in Iraq and Afghanistan, and to highlight the lessons learned from a century of major peacetime fire disasters.

Wartime burns

The historical incidence of thermal injury during conventional (non-nuclear) warfare ranges from 5 to 20% [1, 2]. As with casualties from fire disasters, approximately 20% of thermally injured combat casualties have burns of 20% of the total body surface area (TBSA) or greater [3]. Burns have been responsible for 4% of overall combat mortality since World War II [4]. During current operations, common causes of thermal injury in military personnel include incendiary devices, improvised explosive devices, or ignition of combustible material in armored personnel carriers or aboard ship [5]. Military personnel are also at risk of non-combat-related burns due to mishandling of munitions or carelessness during burning of waste material [6].

Marc G. Jeschke et al. (eds.), Handbook of Burns

Unlike civilian care, military burn care uniquely requires transport of patients along multiple medical treatment facilities termed “echelons” or “roles”; the capabilities of these facilities increase as the casualty moves further from the battlefield (Table 1). During current operations, U. S. military casualties receive rapid initial care at the point of injury from non-medical personnel who receive additional firstaid training (Combat Lifesavers) and/or from combat medics (U. S. Army Healthcare Specialists, U. S Navy Hospital Corpsmen). These interventions include movement away from the source of thermal/ chemical injury, intravenous (IV) or intraosseous line placement, initiation of fluid infusion, and pain management [7, 8]. This emergency, prehospital echelon is referred to as Role I care.

The American Burn Association (ABA) and the American College of Surgeons Committee on Trauma have established criteria for referral of burn patients to a burn center. In general, these criteria should be applied to combat casualties as well, but on the battlefield this may not be immediately possible. Thus, initial burn care to include fluid resuscitation, emergency procedures, and surgical management of concomitant traumatic injuries is currently performed in the Combat Zone by small, austere, highly mobile teams termed Role II-b facilities (U. S. Army Forward Surgical Team, U. S. Navy Forward Resuscitative Surgical System). From there, casualties go to Role III facilities (U. S. Army Combat

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J. B. Lundy, L. C. Cancio

Table 1. USTRANSCOM guidelines for burn flight team transport of patients during conflict in Iraq and Afghanistan

Burns involving 20% or more of the total body surface area

Inhalation injury requiring intubation

Burn and/or inhalation injury with PaO2-to-FiO2 ratio less than 200

High voltage electrical injury

Burns with concomitant traumatic injuries

Burn patients with injury/illness severity warranting Burn Flight Team assistance as determined by the attending, validating, or receiving surgeon

Support Hospital, U. S. Air Force Theater Hospital, U. S. Navy Fleet Hospital or Hospital Ship). This is the first echelon at which definitive surgical care, to include some surgical specialties, is available. Alternatively, many will bypass Role II-b, going directly to Role III facilities. Long-term management of ther- mally-injured U. S.combat casualties requires evacuation, via a Role IV hospital in Germany, to the continental United States (CONUS). There, most thermally injured casualties are cared for at the U. S. Army Burn Center (U. S. Army Institute of Surgical Research, USAISR), Fort Sam Houston, TX. This Role V center, established in 1949, is the only burn center serving the U. S. Department of Defense [9].

The purpose of this section is to review recent US military experience with care of thermally injured combat casualties, from point of injury to definitive care at the USAISR. Topics pertinent to combat burn care include epidemiology, fluid resuscitation, evacuation, lessons learned from the current major theaters of combat operations (Iraq and Afghanistan), definitive care at the USAISR, and the care of host-nation burn patients.

Epidemiology of burns sustained during combat operations

Between 2001 and 2008, during Operations Iraqi and Enduring Freedom, a total of 9.3% of all casualties sustained thermal injury, alone or in combination with other injuries of varying severity (Ms. Susan West, Joint Theater Trauma Registry, personal communication, 27 August 2010). A distinguishing feature of these conflicts has been the large number of

injuries suffered as a result of improvised explosive devices (IEDs) [6]. These devices can be constructed from almost any material that can house an explosive charge. Kauvar et al. found that of 273 thermally injured U. S. military personnel injured in Iraq and Afghanistan and admitted to the U. S. Army Burn Center between March 2003 and May 2005, 62% were wounded as a direct result of hostile activity [5]. Of these, 52% sustained thermal injury as a result of the ignition of an explosive device. Over 70% of these explosive devices were IEDs or vehicle-borne IEDs. The remaining explosion-related burns were the result of landmines, mortars, or rocket-propelled grenades.

Explosions may cause thermal injury by one of two mechanisms: as a result of contact with the heat generated by the explosion itself (also known as “quaternary blast injury”), or as a result of the ignition of fuel or other combustible materials in close proximity to the explosion. The larger body surface area burns typically include burns to the lower extremities and trunk, and are seen more commonly in casualties confined to a burning vehicle [5, 10]. The smaller burns localized to the face and hands are seen more commonly in casualties injured by the explosion itself [5].

Burns to the hands and face comprise a significant portion of burned casualties. In Kauvar’s study, the hands were burned in 80% of patients; the head (predominantly the face) was burned in 77%. Only 15% of casualties had burns isolated to the hands and head; 6% to the hands only. Burns to the hands and face require extensive treatment typically out of proportion to the TBSA burned, which impacts the return to duty rate [5].

Noncombat burns are also common during military operations, accounting for over half of the burns seen during the Vietnam War [10]. Of 102 noncombat burns sustained in the current theaters of operations by May 2005, burning waste (24.5%), ammunition and gunpowder mishaps (20.2%), mishandling of gasoline (17.3%), electrical injuries (8.2%), and scald burns (6.4%) were the leading causes [6]. As demonstrated by Kauvar, combat burns have significantly higher injury severity scores, a higher incidence of other injuries, and a higher incidence of inhalation injury [6]. Despite lower severity, noncombat burns still lead to evacuation of personnel from the theater of operations and a reduction in military readiness. Kauvar

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noted over 30% of noncombat burned patients and over 40% of combat burned patients were unable to return to full military duty.

Preventive measures may be effective on the battlefield. For example, the use of fire-retardant gloves by tank crew members during the 1982 Israeli war in Lebanon decreased the incidence of hand burns from 75 to 7% in the personnel who sustained burns [11]. Fire-retardant flight suits have been reported to decrease both the incidence and severity of thermal injury suffered after military helicopter accidents [12].

Fluid resuscitation and initial burn care in theater

Thermal injury results in fluid shifts from the intravascular space into the interstitium in both burned and (in larger burns) unburned tissue. The goal of burn resuscitation is to replace these intravascular volume losses and to prevent end-organ hypoperfusion and damage, at the lowest possible physiologic cost. Fluid resuscitation of burned soldiers may be complicated by problems which are less frequently present in the civilian setting. Inhalation injury increases fluid resuscitation requirements and is present more frequently in combat casualties (up to 15%) [3]. In addition, the burned combat casualty may have multiple traumatic injuries in addition to burns, increasing the volume and complexity of fluid resuscitation. Meanwhile, lack of burn-specific experience on the part of many deployed providers; relatively austere field hospitals; and the diminution in care which necessarily occurs when casualties are placed aboard evacuation aircraft all compound the difficulty of initial resuscitation [3].

Early experience during current combat operations revealed a trend towards over-resuscitation of thermally injured casualties [3, 13]. Over-resuscita- tion may cause abdominal compartment syndrome, extremity compartment syndrome, pulmonary edema, airway obstruction, and/or progression of wound depth [3, 13, 14]. Together, these complications have been termed “resuscitation morbidity” [15]. As a result, a burn resuscitation guideline was developed and disseminated to all U. S. medical treatment facilities in theater [13]. The guidelines included a 24-hour burn resuscitation flow sheet (Fig. 1), as well as recommendations for the man-

agement of casualties with difficult burn resuscitations. After the implementation of the guideline, US casualties experienced a significant decrease in the combined endpoint of abdominal compartment syndrome and mortality [13].

Other steps taken by the USAISR to improve care of the burned casualty on the battlefield include predeployment training of providers in wartime burn care, the deployment of a burn surgeon to augment the busiest Combat Support Hospital in theater, and a weekly theater-wide video teleconference to communicate patient outcomes and provide feedback [3, 16]. A burn Clinical Practice Guideline was published on the Internet and includes instructions on the management of the difficult resuscitation, indications for and technique of escharotomy, initial wound care, and USAISR contact information.

The USAISR pioneered the modified Brooke formula for fluid resuscitation, which predicts the fluid requirements for the first 24 hours postburn as lactated Ringer’s solution, 2 ml/kg/percent TBSA burned, with half of this volume programmed for delivery over the first 8 hours and half over the following 16 hours. Chung et al., in an attempt to simplify fluid resuscitation rate calculations for adults, developed the ISR Rule of 10s [17]. This rule initiates fluid resuscitation at a rate in ml/hr equal to TBSA X 10 for patients weighing 40 to 80 kg. For every 10 kg above 80, the intial fluid rate is increased by 100 ml/hr. Regardless of how the initial fluid infusion rate is determined, it must be adjusted during the first 48 hours postburn based on the patient’s physiologic response. The primary index of the adequacy of fluid resuscitation is a target urine output of 30–50 ml/hr in adults. The lactated Ringer’s rate is adjusted up or down by roughly 25% increments every hour or two to achieve this target.

Children weighing less than 40 kg cannot be resuscitated using the Rule of Tens. Rather, a weightbased formula such as the modified Brooke formula must be used. The target urine output for children is approximately 1– 2 ml/kg/hr, and the lactated Ringer’s infusion rate is adjusted up or down in order to achieve this target. To prevent hypoglycemia, additional glucose-containing fluids (such as D5W in ½ normal saline) must be given to children at a constant, maintenance rate which is not adjusted.

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Fig. 1. Flow sheet used in theater for documentation of burn resuscitation

Initial burn wound care in the combat zone includes debridement and dressing of burn wounds in the operating room under sterile conditions. This is typically carried out at a level III facility. US military level II and III facilities have wound-care materials to include mafenide acetate, silver sulfadiazine, and silver-impregnated dressings [18]. Classically, burn wounds are treated at the USAISR by alternating mafenide acetate cream in the morning, with silver sulfadiazine cream in the evening. During transport, silver-impregnated dressings offer the advantage of less frequent wound care, but this supposes that the wounds are clean and that burned extremities are well perfused, thus decreasing the need for frequent dressing changes and wound inspection.

Escharotomies are performed during initial wound debridement, or later during resuscitation when indicated. The usual indication for escharoto-

my of an extremity is the loss or progressive diminution of arterial pulsatile flow as determined by Doppler flowmetry. In the deployed setting, it may be prudent to perform escharotomies in patients with large burn size and circumferential (or nearly so) full-thickness burns of an extremity, since monitoring in flight is nearly impossible. This concern should be balanced by the need to obtain good hemostasis before flight, and the potential for escharotomy sites to bleed in flight.

Evacuation of thermally-injured combat casualties

During the Vietnam war, thermally injured military personnel were evacuated to Camp Zama, Japan and remained at that facility for variable amounts of time (up to several weeks) before evacuation to the U. S. [19–22]. Injuries sustained during current op-

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erations have been evacuated more rapidly. Due to the urban environment in Iraq, evacuation times to a Role III Combat Support Hospital are typically less than 60 minutes. In Afghanistan, due to rural operations and difficult terrain, casualties may not arrive at a Combat Support Hospital for up to 4 hours after injury. Evacuation out of the theater of operations to a Role IV hospital takes about 8 hours, and is carried out by a US Air Force Air Evacuation (AE) crew for stable patients, or by an AE crew augmented by a US Air Force Critical Care Air Transport Team (CCATT) for critically ill patients. Landstuhl Regional Medical Center (LRMC) is the Role IV hospital in Germany which supports casualties arriving from both Iraq and Afghanistan. The flight from LRMC to CONUS requires an AE crew, often augmented by a CCATT or by the USAISR Burn Flight Team. The flight from LRMC to the USAISR is over 5,300 miles (8,600 km) and takes approximately 12 to 13 hours [23]. In sum, it is now feasible for a severely burned casualty to arrive at the Army Burn Center within 3–4 days of injury on the battlefield.

The USAISR Burn Flight Team pioneered the air evacuation/transportation of critically ill burn patients in 1951 [21, 22]. The guidelines for Burn Flight Team utilization are listed in Table 1 [23]. The highly specialized BFT crews are equipped and experienced in the management of severely burned, critically-ill casualties and are ideally suited to evacuate multiple casualties during a single mission (Fig. 2). Flights staffed by Burn Flight Teams have carried as many as 13 burned casualties on a single mission during the current conflicts [23]. Burn Flight Teams bring specialized equipment to perform emergency procedures en route such as fiberoptic bronchoscopy, escharotomy, fasciotomy, resuscitation, management of septic shock, decompressive laparotomy, emergency airway procedures, and tube thoracostomy.

Renz et al. conducted a retrospective analysis of the evacuation of war-related burn casualties that were treated at the USAISR [23]. The study encompassed a four-year period from March 2003 to February 2007 and included 540 burned US military casualties. The mean TBSA involved was 16.7% (range 0.1 to 95%) and 342 (63.3%) of casualties were burned as a result of an explosion. During the flight from LRMC to the USAISR, 160 (29.6%) burned casualties required only AE crews; CCATT augmented AE crews

Fig. 2. U.S. Army Burn Flight Team members providing en route critical care to multiple thermally injured casualties

in the care of 174 (32.2%); and the Burn Flight Team cared for 206 (38.1%). Mean transit time for stable patients evacuated by AE crews was 7 days, and transit time for casualties evacuated by CCATT and Burn Flight Teams was less than 4 days [23].

Such rapid evacuation of patients with severe thermal injury carries both risks and benefits. The most notable risk is the inevitable degradation in care that occurs aboard the aircraft, despite the presence of CCATT or Burn Flight Teams. This is particularly important during the first 24 hours postburn, during which rapidly evolving burn shock may make fluid resuscitation difficult even in a U. S. burn center. The most notable benefits are the ability to complete excision and grafting of the burn wound within days of injury, and to place the patient in the burn center before complications such as pneumonia make transport more hazardous. Consideration of these risks and benefits argues in favor of a rather small “window” between hours 24 and 48, during which burn patient evacuation off the battlefield is ideally accomplished.

Definitive management of burned casualties at USAISR

The management of thermally injured combat casualties follows standard principles of burn care. When possible, early burn wound excision (within the first 5 –7 days of injury) with application of

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