Abstract
Field hospitals are usually deployed to locations where, in response to adverse circumstances, normal health care is challenged. It is known that the prevalence of burn wounds in such situations is raised and it is highly likely that a field hospital will need to provide burn care. Many of the features of modern high-quality burn care are not deliverable in a field hospital and it is unlikely the best outcomes can be achieved. Burn care draws heavily on resources. Burns over about 30% total body surface area may cause significant physiological derangement requiring sophisticated critical care. If definitive surgical care of the wound is to be undertaken it is probably better to delay wound excision for about two weeks to allow superficial burns to heal spontaneously. Surgery should ideally be performed in repeated short sessions rather than a single large procedure.
Introduction
Field hospitals must expect to have to deal with burn injury[1]. An increased prevalence of injury from burns is a feature of situations where there is disruption to the functioning of society. In addition to the direct effects of burn injury as a result of weapon wounding, there is the enduring added risk of sustaining burns following alterations in behavior patterns, which remove normal safe working habits[2]. Children are disproportionally more likely to be injured[3].
Over several decades, the management of burn injury in developed health-care systems has improved significantly with survival and good quality of outcome being considered normal even following very large burns[4]. The improvement has been most marked where care is delivered by services incorporating:
organized burn care networks
highly resourced centers of excellence
large multidisciplinary teams
standardized care pathways
use of very early aggressive surgery
sophisticated critical care
rigorous infection prevention and control measures
long-term follow-up with specialized rehabilitation
Provision of this level of complex integrated care is beyond the scope of most field hospitals. That said, even when lacking ideal resources, individual burn care specialists can significantly improve outcomes by making sure basic principles of burn care are applied. Field hospitals may temporarily bring a level of expertise that exceeds the background capability of the indigenous health-care system to provide long-term support for burn survivors.
An implication of the complexity of burn care is the disproportionately high demand it places on resources. In a single field hospital during a short phase in a war fighting scenario, 3% of casualties had burn injuries, but these accounted for 27% of critical care bed usage[5].
This discrepancy between what is realistically deliverable in a field hospital and what would be considered normal outcomes by both the donor and host nations means a great deal of thought must go into understanding the situation in which the facility finds itself. Agreed approaches to clinical pathways for burns, including thresholds of care, are best made in advance. These must be consistent and integrated across the command area of responsibility rather than be idiosyncratic to individual facilities.
If there are several facilities under a unified organizational structure, rationalizing burn care resources should be considered. It would be prudent to ensure there is a degree of additional training to prepare individuals to deliver appropriate initial management. In a complex scenario, centralizing burns expertise to a single identified facility and transferring all burn casualties there is an option.
Pathophysiology
Burn injury has three potential elements:
the cutaneous burn
a systemic physiological response to the burn
inhalation injury
Heat above about 43°C alters protein structure and causes damage to cellular function. A relationship between temperature, duration of exposure and the body’s limited ability to self cool will dictate when tissue exposed to heat will undergo necrosis or sustain recoverable injury. Tissues damaged but not killed by heat will exhibit a marked inflammatory response. For smaller burns this will be limited to the local tissues around the area of burn necrosis, but above a certain threshold a more generalized inflammatory response is initiated. The volume of tissue directly injured by heat can be equated to the area of skin burned, normally expressed as a percentage of the total body surface area (% TBSA).
The inflamed tissues will exhibit marked capillary leakage and fluid will be lost from the intravascular space. Above a certain size of burn, compensatory mechanisms for this fluid loss can be exceeded, leading to physiologically significant hypovolemia, and the clinical manifestations are called burn shock. Burns over about 30% TBSA can trigger a systemic inflammatory response syndrome. The fluid loss occurs over several hours after the injury, and burn shock may not be seen immediately. As the fluid loss is predictable it can be corrected in part by the prophylactic administration of intravenous fluids and the effects of burn shock reduced[6]. It is established practice to use a cut-off of 15% TBSA burn (10% in children), above which additional intravenous fluids should be administered. There is no clear evidence that supports this value. There is growing acceptance that it is safe to give additional fluids orally in burns up to 20% TBSA and this is helpful when resources are scarce[7].
The depth of burn has little impact on the management of burn shock, but alters burn wound treatment. Superficial partial thickness burns should heal spontaneously if managed correctly. Deeper burns will normally require surgical excision and healing by skin grafting.
Inhalation injury is a combination of factors[8]. True heat damage to the upper airways causes a burn injury and airway obstruction secondary to swelling is the concern. Damage to the lower airways is rarely a heat phenomenon; it is normally a chemical injury caused by the inhaled noxious products of combustion. The deleterious effects on pulmonary function of this chemical injury can be delayed and the clinical manifestations may not be evident for hours. Systemic intoxication can occur if these chemicals are absorbed into the circulation.
Initial Management
No assumptions should be made about the adequacy of prehospital interventions. It is important to be certain that the burning process has been stopped and the burn wound has been cooled by using water for about 30 minutes[9]. The water does not have to be sterile. All clothing and jewelry should be removed. Burns are painful and distressing; adequate analgesia should be given as soon as possible. Nonsteroidal antiinflammatory agents should be avoided in the first 48 hours due to the potential renal sequelae.
It is essential that patients with burns undergo a full trauma assessment as for any other type of trauma, and that standard procedures are followed until other injuries are treated or excluded. The systemic effects of a burn may take a while to become apparent and it is important to have a high level of suspicion for other injuries in patients who have signs of hypovolemia or reduced levels of consciousness soon after sustaining a burn. This is particularly important following combat-related burn injury. If there is early hypovolemic shock, this should be treated according to normal measures for hemorrhagic shock irrespective of the burn size.
Burn-injured patients are particularly susceptible to becoming hypothermic. Every effort should be made to keep the patient warm.
An assessment must be made as to the likelihood of inhalation injury by ascertaining the following:
there is a history of:
being in an enclosed space with smoke or flame
reduced level of consciousness at any stage
there are symptoms of:
coughing
difficulty in breathing
There are signs of:
peri- or intraoral burns with soot in the mouth or sputum
stridor
If performed soon after injury, blood gas analysis and chest X-ray can initially be normal even in the presence of significant inhalation injury. If available, carboxyhemoglobin levels can be measured.
Venous access should be secured peripherally or, if necessary, centrally or via an interosseous needle. While it is preferable to avoid cannulating through burned skin, it is acceptable to do so if there is no other option. Blood samples should be analyzed for a full blood count and urea and electrolytes.
A rapid assessment of the size of the burn should be made. This can be done using either the Wallace rule of nines (Figure 19.1) or serial halving[10].
Figure 19.1 Rule of nines
It is difficult to establish an accurate assessment prior to a thorough wash of the burn and it must be accepted that this will be a rough estimate. Initially, therefore, precise calculation of a fluid regimen is unnecessary. Using the “rule of tens”[11]: 10 ml of crystalloid per hour for every estimated % burned (e.g., 40% TBSA = 400 ml per hour) is an acceptable initial administration rate until a more formal assessment is made. If it is not feasible to even make a rough estimate of burn size 500 ml of crystalloid an hour will be safe for a short period. These amounts should be adjusted for small children.
For burns likely to be over 20% TBSA, a urinary catheter and a nasogastric tube should be passed.
It is not normal practice to give prophylactic antibiotics in civilian burn injuries, but combat burn injuries should be assumed to be contaminated. The normal antibiotic prophylaxis for combat casualties should be given for burns sustained in the combat environment. Appropriate measures should be taken to ensure the patient has tetanus immunity.
Further Care
Having assessed for other injuries, the likelihood of inhalation injury, and an estimate of the size of the burn, it is important to decide what further interventions are appropriate. Examples of differing situations that may influence decision-making are:
the patient is part of an overseas military force and needs to be stabilized in preparation for long-haul aeromedical evacuation to receive definitive care in their home country
the patient has a large burn and can be transferred without delay to a burn center a couple of hours away
the patient is a local police officer with an inhalation injury in a country where there is no accessible critical care capability and your facility is only resourced for damage control surgery
the patient is a child who has presented late with a large unhealed burn that exceeds the upper limit acceptable to the host nation’s burn service
The likely clinical pathway and impact on resources over the following hours and days needs to be thought through before committing to a given treatment plan. Decisions may not be solely clinical and command elements should be involved.
Ongoing care, if deemed appropriate, requires multidisciplinary input and involves various aspects of the following.
Inhalation Injury
The initial concern is upper airway swelling, which is more likely to get worse in the first 24 hours. If any degree of upper airway obstruction is present, endotracheal intubation should be performed. Remember, the swelling is likely to be increasing. The majority of patients will be conscious and intubation will be impossible without first anesthetizing the patient. There is a significant impact from having a surgical airway and in difficult cases it should be considered an intervention of last resort.
In cases where there is a high suspicion of inhalation injury, but without evidence of upper airway obstruction, judgment is required to assess if it is considered safe to observe a casualty with a possible inhalation injury unintubated. If so, they should be nursed sitting up in an area where very regular observations can be made.
The pulmonary manifestations of burn injuries rarely occur early. If the airway is clear, the only likely effect of a burn that will cause compromise of respiration in the first few hours is a restriction of chest excursion by a deep circumferential torso burn. This is an indication for emergency chest escharotomy, described below.
Accurate Assessment of the Burn Wound Size
This requires total exposure of the whole body and a thorough wash. This is best performed in a warm, clean, and well-lit operating theater under general anesthesia. This also allows for any necessary surgical interventions to be performed and subsequent dressings. The process of induction of anesthesia can unmask burn-related hypovolemia and appropriate measures should be taken to avoid precipitous hypotension.
Warm antiseptic solution should be used, in large volumes if possible, with vigorous rubbing to remove dirt, carbonaceous residue, residual burned clothing, loose skin, and blisters. Some of the contamination found after explosions and in the battlefield environment contains oily-based products, and a soapy solution should be used. There is no role for delicate dabbing in a misguided attempt to be gentle on the wounds: this process requires aggressive cleaning. Leaving behind dead tissue and contamination will be more harmful.
With the burn fully exposed and cleaned, it is now possible to calculate its size and describe it in terms of % TBSA. Skin which has simple erythema alone is not considered burned. The best aid to this is the Lund and Browder chart (Figure 19.2), although some electronic mapping tools are becoming more available[12].
Related posts:
Chapter 6 – Training and Accreditation
Chapter 3 – Definitions, Needs, Scenarios, Functional Concept, and Modes of Deployment
Chapter 11 – Auxiliary Medical Services in a Field Hospital
Chapter 7 – Personnel
Chapter 18 – Orthopedics in a Field Hospital
Chapter 25 – Infectious Diseases and Public Health in a Field Hospital
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